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Kenji Nakamura

Section

Graduate School of Engineering

Job title

Professor

Degree

博士（工学）（東北大学）
修士（工学）（東北大学）

researchmap

https://researchmap.jp/read0065505

J-GLOBAL ID

200901039261652066

Researcher ID

AAO-9854-2021

Research History 5

2016/04 - Present

Graduate School of Engineering, Tohoku University　Professor
2014/12 - Present

Research Center for Rare Metal and Green Innovation, Tohoku University
2007/08 - 2016/03

Graduate School of Engineering, Tohoku University　Associate Professor
2007/04 - 2007/07

Graduate School of Engineering, Tohoku University　Assistant Professor
2000/04 - 2007/03

Graduate School of Engineering, Tohoku University　Research Associate

Education 2

Tohoku University　Graduate School, Division of Engineering　Electrical and Communication Engineering

- 2000/03/24
Tohoku University　Faculty of Engineering　電気工学科

- 1998/03/25

Committee Memberships 25

日本磁気学会　特任理事

2023/06 - Present
電気学会モータのLife Cycle Assessment 調査専門委員会　委員

2023/04 - Present
電気学会回転機技術委員会　1号委員

2023/04 - Present
電気学会カーボンニュートラルに向けたエネルギー変換システムの磁気応用技術調査専門委員会　幹事

2021/10 - Present
東北電気保安協会　評議員選定委員

2020/06 - Present
電気学会論文委員会（D3グループ）　幹事

2018/04 - Present
電気学会論文委員会（A2グループ）　委員

2006/04 - Present
電気学会回転機技術委員会　幹事

2014/04 - 2023/03
Member

2020/01 - 2022/12
電気学会高密度エネルギー変換システムのための磁気応用技術調査専門委員会　幹事

2018/04 - 2021/03
電気学会エネルギー変換システムの高効率・高機能化のための磁気応用技術調査専門委員会　幹事

2015/04 - 2018/03
電気学会論文委員会（D3グループ）　委員

2008/06 - 2018/03
電気学会新材料パワー半導体の変換器応用に関する技術協同研究委員会　委員

2015/02 - 2017/01
IEEE Magnetics Society Technical Committee　委員

2012/01 - 2015/12
電気学会高効率エネルギー変換のための磁気応用技術調査専門委員会　幹事

2012/04 - 2015/03
電気学会回転機技術委員会　幹事補佐

2011/02 - 2014/03
電気学会特殊同期機の現状と将来動向調査専門委員会　委員

2011/07 - 2013/06
日本応用磁気学会論文賞・学術奨励賞選考委員会　委員

2011/04 - 2013/03
日本磁気学会企画委員会　委員

2009/04 - 2013/03
電気学会電力用磁気デバイスの高機能化技術調査専門委員会　幹事

2009/04 - 2012/03
電気学会東北支部　総務企画幹事

2009/04 - 2012/03
電気学会磁気応用におけるシミュレーションツール活用技術調査専門委員会　幹事補佐

2006/04 - 2009/03
電気学会永久磁石同期機の特性算定技術調査専門委員会　委員

2006/04 - 2009/03
日本応用磁気学会論文賞・学術奨励賞選考委員会　委員

2006/04 - 2008/03
電気学会電力変換・制御システムにおける磁気応用技術調査専門委員会　幹事補佐

2003/04 - 2006/03

Show all ︎Show first 5

Professional Memberships 5

The Institute of Electrical and Electronics Engineers
The Institute of Electrical Engineers of Japan
The Japan Society of Applied Electromagnetics and Mechanics
Society of Automotive Engineers of Japan, Inc.
The Magnetics Society of Japan

Research Interests 5

Magnetic Circuit Analysis
Variable Inductor
Magnetic gear & Magnetic-geared motor
Permanent Magnet Motor
Switched Reluctance Motor

Research Areas 1

Manufacturing technology (mechanical, electrical/electronic, chemical engineering) / Electrical power engineering /

Awards 16

永守賞

2024/09　永守財団　非接触磁気ギヤおよび磁気ギヤード機の高性能化に関する研究開発
学会活動貢献賞

2023/09　日本磁気学会　INTERMAG2023 組織委員会
論文賞

2023/09　日本磁気学会　Reluctance Network Model of IPM Motor Representing Dynamic Hysteresis Characteristics for High-Accuracy Iron Loss Calculation Considering Carrier Harmonics
論文賞

2022/09　日本磁気学会　Performance Improvement of Spoke- shaped Interior Permanent Magnet Magnetic Gear
出版賞

2021/08　日本磁気学会　パワーマグネティクスのための応用電磁気学
出版賞「磁気回路法によるモータの解析技術（科学情報出版）」

2019/09　日本磁気学会
2014 AUMS Young Researcher AWARD

2014/10/30　The Asian Union of Magnetics Societies (AUMS)　Innovative works on variable inductors and application to reactive power compensators in electric power systems
日本磁気学会論文賞

2008/09/14　日本磁気学会　3相一体構造可変インダクタの基礎特性
電気学会優秀論文発表賞

2008/03/20　電気学会　2-149 固定子極間に永久磁石を有するSRモータの特性
電気学会優秀論文発表賞

2008/03/20　電気学会　固定子極間に永久磁石を挿入したスイッチトリラクタンスモータの開発
電気学会優秀論文発表賞

2006/03/16　電気学会　2-145 Reluctance Network AnalysisによるPM発電機の特性算定
応用磁気学会優秀講演賞

2005/11/18　日本応用磁気学会　田形磁心のRNAモデルにおける渦電流のモデリング手法
応用磁気学会学術奨励賞

2004/09/22　日本応用磁気学会　磁気飽和を考慮したSRMの簡易磁気回路モデル
電気学会優秀論文発表賞

2003/03/31　電気学会　MAG-02-173 簡易磁気回路モデルを用いた埋込磁石モータの動特性解析
応用磁気学会優秀講演賞

2002/11/06　日本応用磁気学会　RNAによるギャップレス線形可変インダクタの特性算定
電気学会論文発表賞B

2000/04/01　電気学会　直交磁心形３相可変インダクタの制御側巻線結線法に関する考察

Show all ︎Show 5

Papers 252

Measuring the Operating Condition of Induction Motor Using High-Sensitivity Magnetic Sensor

Akane Kobayashi, Kenji Nakamura, Takahito Ono

Sensors　2025/07/18

DOI： 10.3390/s25144471 　
Experimental Improvement of Speed-Torque Characteristics in Magnetic-Geared Switched Reluctance Motor

Keigo Iwaki, Kenji Nakamura

IEEE Transactions on Magnetics　2025

DOI： 10.1109/TMAG.2025.3548307 　
Eddy Current Loss Reduction in Flux-Modulated-type Magnetic Gears by Unequal Division of Magnets

Emiri Asahina, Yuichi Tachiya, Kenji Nakamura

IEEE Transactions on Magnetics　2025

DOI： 10.1109/TMAG.2025.3546988 　
Prototype Verification of Flux Reversal Motor With Cross-Pole Shape Stator

Yue Yu, Kenji Nakamura

IEEE Transactions on Magnetics　2024/09

DOI： 10.1109/TMAG.2024.3430941 　
Investigation of Torque Dependence of Losses in Flux-Modulated-type Magnetic Gear

Asahina E., Nakamura K.

Transaction of the Magnetics Society of Japan Special Issues　8　(1)　57-61　2024/05/01
Publisher: The Magnetics Society of Japan
DOI： 10.20819/msjtmsj.24tr814 　

eISSN： 2432-0471

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In recent years, there has been a strong demand for electric motors to be reduced in size and weight and increased their output power density by increasing the rotational speed over tens of thousands of rpm. However, it is challenging to realize mechanical gears that can operate at such ultra-high speed due to mechanical contact. Magnetic gears have been getting attention recently because they can change speed and torque without mechanical contact. Thus, they have low vibration, noise, wear, and friction heating. These features are desirable for ultra-high-speed applications. In particular, a flux-modulated-type magnetic gear is expected to be put into practical use because it has a higher torque density than other kinds of magnetic gears. However, the torque dependence of losses is not fully clarified yet. In this paper, the torque dependence of losses in the prototype magnetic gear is clarified by experiment and finite element method (FEM), and the influence of pole-pairs, an important parameter in determining the gear ratio of magnetic gears, is discussed.
Reluctance Network Model of V-Type IPMSM for Accurate and Practical Design

Yoshiki Hane, Kenji Nakamura

IEEE Transactions on Magnetics　2024

DOI： 10.1109/TMAG.2024.3425611 　
Experimental Verification of Torque Density Improvement by Magnetic Interaction in 500 N·m IPM-Type Magnetic-Geared Motor

Keigo Iwaki, Koki Ito, Kenji Nakamura

IEEE Transactions on Magnetics　2023/11

DOI： 10.1109/TMAG.2023.3291372 　
A Novel Transverse-Flux-Type Switched Reluctance Motor With Reverse Bias Permanent Magnets Peer-reviewed

Ayumi Nagai, Kazuhide Mitsuya, Kenji Nakamura

IEEE Transactions on Industry Applications　1-9　2023/05
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
DOI： 10.1109/TIA.2023.3245580 　

ISSN： 0093-9994

eISSN： 1939-9367
Flux Barrier Shape for Reluctance Torque Improvement of Distributed-Winding Interior Permanent Magnet Motor

田村一樹, 中村健二, 成瀬賢哉, 萱野雅浩

日本磁気学会学術講演概要集　47th　(1)　40-44　2023
Publisher: The Magnetics Society of Japan
DOI： 10.20819/msjtmsj.24tr808 　

ISSN： 1882-2959

eISSN： 2432-0471

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As electrification progresses in various fields, permanent magnet (PM) machines have been attracting attention because of their compactness, high power, and high efficiency. Among them, interior permanent magnet (IPM) machines with a rotor core in which permanent magnets are embedded can achieve higher power and efficiency than conventional PM machines since they can utilize both magnetic and reluctance torque. This paper focuses on distributed-winding IPM machines, assuming the use of bonded magnets, and investigates various flux barrier shapes that can improve reluctance torque using the finite element method (FEM).
Measurement of Air Gap Flux Density Waveforms of Flux-Modulated-type Magnetic Gear

岡崎晃洋, 角貴則, 中村健二, 進士智一, 武田啓司

電気学会研究会資料(Web)　8　(MAG-23-021-030)　35-39　2023
Publisher: The Magnetics Society of Japan
DOI： 10.20819/msjtmsj.24tr803 　

eISSN： 2432-0471

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Magnetic gears, which can transmit power without any mechanical contact, offer lower vibration and acoustic noise compared with conventional mechanical gears. They also have an advantage in terms of maintenance. Among the various types of magnetic gears, the flux-modulated-type magnetic gear has recently garnered attention because of its higher torque density and efficiency. This gear consists of concentric inner and outer rotors and pole pieces placed between two rotors and works as a gear based on flux modulation theory. Therefore, measurement and analysis of the modulated fluxes in the air gaps are essential since these fluxes directly contribute to torque and efficiency. This paper presents a system for measuring flux density waveforms in the air gap of the flux-modulated-type magnetic gear. The measured waveforms are compared with those calculated using a finite element method (FEM).
Drive Range Expansion of Axial-Flux SR Motor for Compact EV

西海悠介, 中澤貫太, 中村健二

電気学会研究会資料(Web)　47th　(MAG-23-021-030)　45-51　2023
Publisher: The Magnetics Society of Japan
DOI： 10.20819/msjtmsj.24tr804 　

ISSN： 1882-2959

eISSN： 2432-0471

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In previous papers, axial-flux switched reluctance motors (AFSRMs) for compact electric vehicles (EVs) were prototyped, and EV driving tests were successfully conducted. However, it was clear that the conventional control method, called instantaneous phase torque distribution control (IPTDC), has a narrow torque-speed range. This paper presents an improved control method that can expand the torque-speed range, especially in high-speed regions. Moreover, it proposes an average torque control method that can maintain a large torque for even higher speed regions.
Experimental Consideration on Influence of Magnetic After Effect on Gap Magnetic Field and Applicability of Conventional Hysteresis Models for Particle Accelerator Electromagnets Peer-reviewed

羽根吉紀, 菅原賢悟, 中村健二, 石禎浩

IEEJ Transactions on Electrical and Electronic Engineering　18　500-505　2022/12

DOI： 10.1002/tee.23749 　

ISSN： 1931-4973

eISSN： 1931-4981
Cogging Torque Reduction of Integer Gear Ratio Axial-Flux Magnetic Gear for Wind-Power Generation Application by Using Two New Types of Pole Pieces

Boqun Dai, Kenji Nakamura, Yuma Suzuki, Yuichi Tachiya, Kingo Kuritani

IEEE Transactions on Magnetics　58　(8)　1-5　2022/08
Publisher: Institute of Electrical and Electronics Engineers ({IEEE})
DOI： 10.1109/TMAG.2022.3159002 　
Cogging Torque Reduction of Axial-flux Magnetic Gear with Integer Gear Ratio by Unequal-width Pole-pieces

Dai B., Nakamura K., Suzuki Y., Tachiya Y., Kuritani K.

Transaction of the Magnetics Society of Japan Special Issues　6　(1)　58-62　2022/05/01
Publisher: The Magnetics Society of Japan
DOI： 10.20819/msjtmsj.22tr510 　

eISSN： 2432-0471

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In some cases, magnetic gears are required to have an integer gear ratio based on the design requirements of the entire system, which results in a larger cogging torque in a high-speed rotor that causes vibration, noise, and startup error. The conventional skew rotor structure is a well-known countermeasure for cogging torque. However, it is complicated and difficult to assemble, especially in an axial-flux magnetic gear. To solve this problem, this paper presents a new type of pole-pieces called the unequal-width type. The validity of the proposed pole-pieces is proved both with the three-dimensional finite element method (3D-FEM) and in an experiment.
Principle Verification and Transmission Characteristics Improvement of Induction/Synchronous Magnetic Gears

Mizuana Y., Nakamura K., Suzuki Y., Tachiya Y., Kuritani K.

Transaction of the Magnetics Society of Japan Special Issues　6　(1)　63-68　2022/05/01
Publisher: The Magnetics Society of Japan
DOI： 10.20819/msjtmsj.22tr511 　

eISSN： 2432-0471

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Magnetic gears can transmit torque and change speed without any mechanical contacts. Therefore, vibration and acoustic noise are very low, and maintainability is high. Various kinds of magnetic gears have been proposed. Among them, the flux-modulated-type magnetic gear has a higher torque density and efficiency compared to conventional magnetic gears. Magnetic gears have a torque limiter function that allows them to step out and shut off power when overloaded. However, after stepping out, they cannot transmit power again unless the load torque is removed to some extent. This paper presents a novel induction/synchronous magnetic gear with a cage rotor bar. In addition, the prototype induction/synchronous magnetic gears are tested.
Orthogonal-Core-Type Variable Inductor Consisting of Cut Core and Laminated Core

Sato T., Nakamura K., Ohinata T., Arimatsu K.

Transaction of the Magnetics Society of Japan Special Issues　6　(1)　53-57　2022/05/01
Publisher: The Magnetics Society of Japan
DOI： 10.20819/msjtmsj.22tr518 　

eISSN： 2432-0471

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Variable inductors, which consist of magnetic cores and a primary dc and secondary ac winding, can control the effective inductance of the secondary ac winding continuously with the primary dc current due to the magnetic saturation effect. Therefore, they can be applied as reactive power compensators in electric power systems. Variable inductors have desirable features such as a simple and robust structure, low cost, and high reliability. This paper presents a novel orthogonal-core-type variable inductor composed of two types of cores: a cut core and a laminated core. By combining them, the lamination stacking of both cores can be aligned with each other, thereby preventing short circuits between laminations. In this paper, the basic characteristics of the proposed variable inductor are investigated by both simulation and experiment.
Prototype Evaluation of Inset PM Motor made of NANOMET^® Laminated Core

Yu Y., Hiramoto S., Nakamura K.

Transaction of the Magnetics Society of Japan Special Issues　6　(1)　49-52　2022/05/01
Publisher: The Magnetics Society of Japan
DOI： 10.20819/msjtmsj.22tr517 　

eISSN： 2432-0471

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Non-oriented silicon steel, which is commonly used as motor cores, is less expensive and has high flux density, while large iron loss under high-frequency region is a problem for high-speed applications. In contrast, NANOMET^®, one of the nanocrystalline soft magnetic alloys, is expected to be a next-generation motor core material since it has high flux density as almost the same as the conventional non-oriented silicon steel and lower iron loss. In a previous paper, prototype tests of a switched reluctance (SR) motor made of NANOMET^® laminated core were conducted, and it was clear that the iron loss is significantly reduced and the efficiency is improved. This paper presents the prototype tests results of an inset permanent magnet (InPM) motor made of NANOMET® laminated core.
Outer-Rotor-type High-Speed PM motor with Segmented-shaped Rotor

Sakurai S., Uchiyama Y., Nakamura K.

Transaction of the Magnetics Society of Japan Special Issues　6　(1)　69-73　2022/05/01
Publisher: The Magnetics Society of Japan
DOI： 10.20819/msjtmsj.22tr504 　

eISSN： 2432-0471

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Cooling fans are widely used in communication base station servers since they have a good balance between performance and cost. Cooling fan motors generally have an outer rotor structure because the fan can be directly mounted on the rotor. However, the outer-rotor-type motor has a low degree of freedom in design since the rotor core is thin. Therefore, most of the cooling fan motors have a surface permanent magnet (SPM) structure, and thus, it has ferrite magnets to prevent eddy current losses in magnets and cannot use a reluctance torque. This paper presents a novel outer-rotor-type high-speed PM motor with a segmented-shaped rotor. It can efficiently use reluctance torque in addition to magnet torque, and reduce eddy current loss in magnets even though the rotor has sintered Nd-Fe-B magnets. The usefulness of the proposed motor is proved by comparing it with an inset PM motor using a three-dimensional finite element method (3D-FEM) and prototype tests.
Investigating Characteristics of SMC-based SR Motor Manufactured by using Wire Electric Discharge Machining

Mitsuya K., Nakamura K.

Transaction of the Magnetics Society of Japan Special Issues　6　(1)　34-38　2022/05/01
Publisher: The Magnetics Society of Japan
DOI： 10.20819/msjtmsj.22tr501 　

eISSN： 2432-0471

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Soft magnetic composite (SMC) is expected to be a next-generation motor cores since it has three-dimensional magnetic isotropy and excellent high-frequency characteristics. However, a metal die is required to manufacture an SMC-based motor core, which results in high costs. In particular, in the prototype evaluation stage, the high costs prevent the use of various cut-and-try procedures. This paper investigates the characteristics of an SMC-based SR motor manufactured by using wire electric discharge machining from an SMC bulk body.
Experimental Study on Losses of Axial-Flux-Type Switched Reluctance Motor for Compact EV

Sato K., Nakamura K.

Transaction of the Magnetics Society of Japan Special Issues　6　(1)　39-43　2022/05/01
Publisher: The Magnetics Society of Japan
DOI： 10.20819/msjtmsj.22tr502 　

eISSN： 2432-0471

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A switched reluctance motor (SRM) has a simple and robust structure since it consists of only stator cores, rotor cores and windings wounded around the stator poles. In previous papers, axial-flux-type switched reluctance motors (AFSRMs) were prototyped and installed into the rear wheels of a compact electric vehicle (EV). Driving tests were conducted with success. However, there was a difference between the losses calculated by electromagnetic field analysis and those measured from the prototype AFSRM. In this paper, the causes of the difference are investigated in experiments.
Basic Characteristics of Transverse-Flux-Type Switched Reluctance Motor with Permanent Magnets Applying Reverse Bias Magnetic Field

Nagai A., Mitsuya K., Nakamura K.

Transaction of the Magnetics Society of Japan Special Issues　6　(1)　44-48　2022/05/01
Publisher: The Magnetics Society of Japan
DOI： 10.20819/msjtmsj.22tr503 　

ISSN： 2432-0471

eISSN： 2432-0471

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Switched reluctance motors (SRMs), which consist of only iron cores and windings, are attracting attention as simple, robust, and inexpensive variable-speed motors. This paper presents a novel transverse-flux-type switched reluctance motor (TFSRM), that has permanent magnets in the rotor cores for applying a reverse bias magnetic field. The proposed TFSRM can expand the operating point from the 1st quadrant into the 3rd quadrant on B-H characteristic by the reverse bias magnetic field, which increases both torque and efficiency. The advantages of the proposed TFSRM is proved by using a three-dimensional finite element method (3D-FEM).
Dynamic Hysteresis Modeling Taking Skin Effect Into Account for Magnetic Circuit Analysis and Validation for Various Core Materials

Yoshiki Hane, Kenji Nakamura

IEEE Transactions on Magnetics　58　(4)　1-12　2022/04
Publisher: Institute of Electrical and Electronics Engineers ({IEEE})
DOI： 10.1109/TMAG.2022.3145101 　
Design and Prototype Tests of Ultra High Speed Magnetic Gear

三ツ谷和秀, 立谷雄一, 鈴木雄真, 操谷欽吾, 中村健二

電気学会研究会資料(Web)　46th　(MAG-22-029-036)　85-91　2022
Publisher: The Magnetics Society of Japan
DOI： 10.20819/msjtmsj.23tr516 　

ISSN： 1882-2959

eISSN： 2432-0471

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In recent years, there has been strong demand for high-speed motors over 50,000 rpm has been strongly required to be reduced in size and weight and have an increased the output power density. Magnetic gears can change speed and torque without mechanical contact. Thus, they have low vibration, noise, wear, and friction heating. These features are desirable for high-speed applications. Flux-modulated type magnetic gears are expected to be put into practical use because they have a higher torque density than other kinds of magnetic gears. This paper describes the design of an ultra-high-speed magnetic gear whose maximum input speed is 80,000 rpm and presents the prototype test results. First, the dimensions of the magnetic gear are optimized by using two-dimensional finite element analysis (2D-FEM). Next, the optimized magnetic gear is evaluated by using 3D-FEM. The result of prototype tests shows that the maximum efficiency of the magnetic gear is 94.9% at low speed, and it is kept over 80% at 80,000 rpm.
Basic Examination of SR Motor with Aluminum Coils

朝雛えみり, 中村健二, 柳沢恭平, 古屋勇太

日本磁気学会学術講演概要集　46th　(1)　45-48　2022
Publisher: The Magnetics Society of Japan
DOI： 10.20819/msjtmsj.23tr504 　

ISSN： 1882-2959

eISSN： 2432-0471

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In recent years, the development of air mobility and drones has been active. For these applications, permanent magnet (PM) motors are widely used due to their high power and efficiency. However, their cooling systems are limited to a simple air-cooling type because of size and weight limitations. Since air mobility and drones require an ultra-high power density, such insufficient cooling systems may cause irreversible demagnetization in magnets. Switched reluctance (SR) motors have no permanent magnets, consisting of only iron cores and windings, they are attracting attention as a simple, robust, and inexpensive variable-speed motor. The torque density of conventional SR motors is generally lower than those of PM motors. Hence, this paper focuses on aluminum coils, which have a higher degree of freedom of shape and are lighter than conventional copper coils. The basic characteristics of the proposed SR motor were calculated by using a three-dimensional finite element method (3D-FEM). The calculation results show that the aluminum coils are superior to the conventional copper ones in terms of torque and efficiency when the winding space factor of the aluminum coils exceeds 70%. Furthermore, the power density, which is a key indicator for air mobility, was over 1 kW/kg.
Orthogonal-Core-type Variable Inductor with Permanent Magnets

会津翔太, 中村健二, 大日向敬, 有松健司

日本磁気学会学術講演概要集　46th　(1)　67-72　2022
Publisher: The Magnetics Society of Japan
DOI： 10.20819/msjtmsj.23tr508 　

ISSN： 1882-2959

eISSN： 2432-0471

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Variable inductors consist of a magnetic core, a primary DC winding, and a secondary AC winding. Due to the magnetic saturation effect, they can control the effective inductance of the secondary AC winding with the primary DC current. Therefore, they can be used as reactive power compensators in electric power systems. This paper presents a novel orthogonal-core-type variable inductor in which permanent magnets are inserted in the magnetic path of the primary DC flux. The proposed variable inductor can generate a certain reactive power when the primary DC current is zero, and it can control the reactive power from lead to lag by changing the primary DC current from positive to negative.
Various Examinations on Calculation Accuracy of DC Hysteresis Loops by LLG Equation

渡部樹, 羽根吉紀, 中村健二

電気学会研究会資料(Web)　2022　(SA-22-001-004.006-017/RM-22-001-004.006-017)　150-157　2022
Publisher: The Institute of Electrical Engineers of Japan
DOI： 10.1541/ieejfms.143.150 　

ISSN： 0385-4205

eISSN： 1347-5533

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Quantitative analysis of iron loss taking magnetic hysteresis behavior into account is essential to loss reduction in electric machines. In the previous research, a novel magnetic circuit model, which incorporates a play model and a Cauer circuit, was proposed. Besides, the play model can be derived from dc hysteresis loops calculated by a simplified Landau-Lifshitz-Gilbert (LLG) equation. However, this method cannot necessarily calculate dc hysteresis loops with high accuracy in all cases so that there is potential for further improvement in its calculation accuracy. Therefore, in this paper, the calculation accuracy of the simplified LLG equation is examined in detail under various conditions.
A Study on Simple Waveform Control Method in Magnetic-Properties Measurement System for Ring Core Using myRIO

川口正隆, 羽根吉紀, 中村健二

日本磁気学会学術講演概要集　46th　(1)　49-54　2022
Publisher: The Magnetics Society of Japan
DOI： 10.20819/msjtmsj.23tr505 　

ISSN： 1882-2959

eISSN： 2432-0471

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The sinusoidal magnetic flux waveform control is necessary in the measurement of magnetic-properties of soft magnetic materials. Although various control methods were proposed in the previous studies, most of them have the practical problem of requiring some special equipment. Therefore, this paper presents the simple and affordable measurement system by using the myRIO, which is a general-purpose controller used in many universities, for the waveform control. The proposed method is validated by measuring the dc and ac magnetic-properties of a ring core made of a non-oriented silicon steel.
Efficiency Improvement of Outer-Rotor-type High-Speed PM motor with Segmented-shaped Rotor

櫻井将, 中村健二

日本磁気学会学術講演概要集　46th　(1)　61-66　2022
Publisher: The Magnetics Society of Japan
DOI： 10.20819/msjtmsj.23tr507 　

ISSN： 1882-2959

eISSN： 2432-0471

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Cooling fans are widely used in communication base station servers because they have a good balance between cooling performance and cost. Nowadays, cooling fans are required to be improved their cooling performance. Thus, the output power and efficiency of the fan motors should be improved. In a previous paper, a novel segment PM motor was proposed, which has segmented cores and permanent magnets in the rotor. The proposed PM motor has large torque and less eddy current loss in magnets. The prototype tests clarified that the proposed PM motor has higher power and efficiency than a conventional fan motor. However, the measured mechanical loss was larger than the expected one. This paper presents a simple method for estimating the mechanical loss of the proposed PM motor. Furthermore, the mechanical loss improvement by the lightweight of the rotor core and case is discussed.
Improvement of Current Unbalance of Transverse-Flux-type SR Motor

永井歩美, 中村健二

日本磁気学会学術講演概要集　46th　(1)　92-96　2022
Publisher: The Magnetics Society of Japan
DOI： 10.20819/msjtmsj.23tr517 　

ISSN： 1882-2959

eISSN： 2432-0471

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Transverse-flux-type switched reluctance motors (TFSRMs) have a three-dimensional structure and are expected to exhibit a larger torque than conventional SRMs due to their high winding -space factor. However, a trial three-phase TFSRM was found to have an unbalanced current and torque, which causes vibration and acoustic noise. The mechanism of this unbalanced current has not been clarified yet. This paper investigates the cause of the unbalanced current by using a three-dimensional finite element method (3D-FEM). Furthermore, it presents a two-phase TFSRM that improves the unbalanced current.
Proposal of Magnetic-Geared SR Motor for In-wheel Drive type Compact EV Peer-reviewed

伊藤亘輝, 中村健二

日本磁気学会学術講演概要集　46th　(1)　55-60　2022
Publisher: The Magnetics Society of Japan
DOI： 10.20819/msjtmsj.23tr506 　

ISSN： 1882-2959

eISSN： 2432-0471

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Magnetic-geared motors and direct-drive permanent magnet motors have attracted attention as in-wheel motors for electric vehicles (EVs) since they have the advantage of high torque density. However, these motors have the problem that it is difficult to achieve the wide speed-torque characteristics required for EVs. This paper proposes a novel magnetic-geared motor that consists of a flux-modulated type magnetic gear and a switched reluctance (SR) motor, which has the wide speed-torque characteristics in nature.
Basic Examination of Cross-pole-type Flux-Reversal Motor

YU Y., 中村健二

日本磁気学会学術講演概要集　46th　(1)　97-101　2022
Publisher: The Magnetics Society of Japan
DOI： 10.20819/msjtmsj.23tr518 　

ISSN： 1882-2959

eISSN： 2432-0471

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In recent years, electrification has been promoted as part of the measures toward global warming, and demand for power-saving and high-efficiency motors is increasing. Among the various types of motors, permanent magnet synchronous motors (PMSMs) are used in various fields, such as electric vehicles and home appliances. However, PMSMs have issues with mechanical strength and cost. In comparison, flux reversal motors (FRMs) have a simple reluctance rotor, and a stator with armature windings and permanent magnets. Due to the high torque density of FRMs the same as PMSMs, they are expected to be used in multiple applications such as for electric vehicles and wind power generations. However, the conventional FRM has a problem with large eddy current loss in magnets. This paper presents a novel FRM with a cross-shaped stator pole that reduces the eddy current loss. The usefulness of the proposed FRM is proved by a three-dimensional finite element method (3D-FEM).
A Novel Magnetic-Geared Motor integrating Magnetic Gear and SR Motor

伊藤亘輝, 中村健二

電気学会研究会資料(Web)　(MAG-22-102-120/MD-22-120-138/LD-22-073-091)　2022

DOI： 10.1109/TMAG.2023.3276873 　
Prototype Tests of Induction/Synchronous Magnetic Gears

Y. Mizuana, K. Nakamura, Y. Suzuki, Y. Tachiya, K. Kuritani

2022 International Power Electronics Conference, IPEC-Himeji 2022-ECCE Asia　1261-1265　2022

DOI： 10.23919/IPEC-Himeji2022-ECCE53331.2022.9807137 　
Hysteresis Analysis under DC-Bias by using Magnetic Circuit Model Combined with Play Model Peer-reviewed

Hosono Y., Hane Y., Nakamura K.

Transaction of the Magnetics Society of Japan Special Issues　5　(1)　27-31　2021/05/01
Publisher: The Magnetics Society of Japan
DOI： 10.20819/msjtmsj.21tr301 　

eISSN： 2432-0471

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Quantitative analysis of iron loss taking magnetic hysteresis behavior into account is essential to development of high-efficiency electric machines. In a previous paper, a novel magnetic circuit model combined with a play model which is one of the phenomenological models of magnetic hysteresis, was proposed. It was clear that the proposed model can calculate the hysteresis loop of the magnetic reactor in high speed and high accuracy. However, the calculation accuracy of dc-biased magnetic reactor has not been investigated. This paper discusses the calculation accuracy of dc-biased hysteresis loops by comparing with experimental results.
Prototype Evaluation of High-Speed SR Motor Made of NANOMET® Laminated Core Peer-reviewed

Nagai A., Mitsuya K., Hiramoto S., Nakamura K.

Transaction of the Magnetics Society of Japan Special Issues　5　(1)　22-26　2021/05/01
Publisher: The Magnetics Society of Japan
DOI： 10.20819/msjtmsj.21tr303 　

ISSN： 2432-0471

eISSN： 2432-0471

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A switched reluctance (SR) motor has a simple and robust structure, is low in cost, and operates maintenance-free. Therefore, the SR motor is expected to be used in various fields, especially for high-speed applications. This paper focuses on a novel soft magnetic material, called NANOMET®, that contains nanocrystalline Fe–Si–B–P–Cu quinary alloys. It has almost the same saturation flux density as conventional non-oriented Si steel and remarkably low core loss. In this paper, a 12/8-pole SR motor made of NANOMET® laminated core is prototyped and compared with a conventional one made of non-oriented Si steel. As a result, the torque characteristics of both SR motors were almost the same. It was also found that the iron loss of the SR motor made of NANOMET® was significantly reduced, which lead to an efficiency improvement of 10% in comparison with the conventional one made of non-oriented Si steel.
Prototype Tests of Outer-Rotor-type High-Speed PM Motor Peer-reviewed

S. Sakurai, K. Nakamura

Journal of the Magnetics Society of Japan　45　(3)　70-74　2021/05/01
Publisher: The Magnetics Society of Japan
DOI： 10.3379/msjmag.2105r012 　

ISSN： 1882-2924

eISSN： 1882-2932
A Consideration of Magnetostriction Force Calculation for Transformer Core by Using Reluctance Network Analysis Peer-reviewed

Y. Hane, K. Nakamura, N. Kurita

Journal of the Magnetics Society of Japan　45　(3)　56-60　2021/05/01
Publisher: The Magnetics Society of Japan
DOI： 10.3379/msjmag.2105r009 　

ISSN： 1882-2924

eISSN： 1882-2932
Performance Improvement of Spoke-shaped Interior Permanent Magnet Magnetic Gear Peer-reviewed

Y. Mizuana, K. Nakamura, Y. Suzuki, Y. Oishi, Y. Tachiya, K. Kuritani

Journal of the Magnetics Society of Japan　45　(3)　50-55　2021/05/01
Publisher: The Magnetics Society of Japan
DOI： 10.3379/msjmag.2105r008 　

ISSN： 1882-2924

eISSN： 1882-2932
Investigation of Magnetic Interaction of IPM-Type Magnetic-Geared Motor Peer-reviewed

Koki Ito, Kenji Nakamura

IEEE Transactions on Magnetics　57　(2)　1-5　2021/02
Publisher: Institute of Electrical and Electronics Engineers ({IEEE})
DOI： 10.1109/TMAG.2020.3020121 　

ISSN： 0018-9464

eISSN： 1941-0069
磁気ヒステリシスが加速器用電磁石のギャップ磁場に与える影響に関する基礎検討

菅原賢悟, 石禎浩, 中村健二, 羽根吉紀

電気学会研究会報告　SA21004　9-12　2021
Reluctance network model of interior permanent magnet motor with polar anisotropic magnet

Y. Hane, Y. Uchiyama, K. Nakamura

Journal of the Magnetics Society of Japan　45　(5)　125-130　2021
Publisher: Magnetics Society of Japan
DOI： 10.3379/msjmag.2109R002 　

ISSN： 1882-2932 0285-0192
A novel reluctance network model applicable for open magnetic circuits Peer-reviewed

Y. Hane, K. Sugahara, K. Nakamura

Journal of the Magnetics Society of Japan　45　(4)　112-117　2021

DOI： 10.3379/msjmag.2107R006 　

ISSN： 0285-0192

eISSN： 1882-2932
A Novel Control Method for In In-wheel SR Motor to Implement Torque Vectoring Control for Compact EV Peer-reviewed

Naoki Tashiro, Kenji Nakamura

IEEJ Journal of Industry Applications　2021
Publisher: Institute of Electrical Engineers of Japan (IEE Japan)
DOI： 10.1541/ieejjia.21001098 　

ISSN： 2187-1094

eISSN： 2187-1108
A Novel Control Method for In-wheel SR Motor to Implement Torque Vectoring Control for Compact EV Peer-reviewed

Naoki Tashiro, Shota Sawasato, Kenji Nakamura

2020 23rd International Conference on Electrical Machines and Systems (ICEMS)　2041-2045　2020/11/24
Publisher: IEEE
DOI： 10.23919/icems50442.2020.9291002 　
Comparison of Two Different Interior Permanent Magnet Type Low-speed Rotor Structures of Axial-Flux Magnetic Gear Peer-reviewed

B. Dai, K. Nakamura, Y. Suzuki, Y. Oishi, Y. Tachiya, K. Kuritani

2020 23rd International Conference on Electrical Machines and Systems (ICEMS)　1748-1751　2020/11/24
Publisher: IEEE
DOI： 10.23919/icems50442.2020.9290886 　
Proposed and Verification of Torque Equation of IPM-type Magnetic-Geared Peer-reviewed

Koki Ito, Kenji Nakamura

2020 23rd International Conference on Electrical Machines and Systems (ICEMS)　898-901　2020/11/24
Publisher: IEEE
DOI： 10.23919/icems50442.2020.9291018 　
Dynamic Hysteresis Modeling for Magnetic Circuit Analysis by Incorporating Play Model and Cauer’s Equivalent Circuit Theory Peer-reviewed

Yoshiki Hane, Kenji Nakamura

IEEE Transactions on Magnetics　56　(8)　1-6　2020/08

DOI： 10.1109/TMAG.2020.3004355 　

ISSN： 0018-9464

eISSN： 1941-0069
High-Speed SR Motor Made of Soft Magnetic Composite for Electric Power Tools Peer-reviewed

永井歩美, 中村健二, 佐藤重典, 牧野彰宏

日本磁気学会論文特集号(Web)　4　(1)　91-95　2020/05

DOI： 10.20819/msjtmsj.20TR410 　

ISSN： 2432-0471
磁気ギヤードモータの電流位相角が脱調トルクに及ぼす影響 Peer-reviewed

伊藤亘輝, 中村健二

日本磁気学会論文特集号　4　(1)　86-90　2020/05

DOI： 10.20819/msjtmsj.20TR423 　
1層毎交互巻高周波アモルファストランスを有する直流連系用DC-DCコンバータの特性 Peer-reviewed

大津諭史, 中村健二

日本磁気学会論文特集号　4　(1)　81-85　2020/05

DOI： 10.20819/msjtmsj.20TR422 　
アウターロータ型高速PMモータの高効率化に関する検討 Peer-reviewed

櫻井将, 中村健二

日本磁気学会論文特集号　4　(1)　72-76　2020/05

DOI： 10.20819/msjtmsj.20TR404 　
インセット型高速PMモータの試作試験 Peer-reviewed

内山裕太郎, 中村健二, 一ノ倉理, 後藤博樹, 郭海蛟

日本磁気学会論文特集号　4　(1)　67-71　2020/05

DOI： 10.20819/msjtmsj.20TR421 　
アキシャルギャップ型SRモータの解析精度改善と性能向上に関する検討 Peer-reviewed

相澤拓毅, 中村健二

日本磁気学会論文特集号　4　(1)　62-66　2020/05

DOI： 10.20819/msjtmsj.20TR420 　
Prediction Accuracy Improvement of Magnetic Properties of Heavy Rolled Silicon Steel Sheet by using LLG Equation Peer-reviewed

Hane Y., Nakamura K., Kawase T., Hosokawa N., Kurimoto N.

Transaction of the Magnetics Society of Japan Special Issues　4　(1)　57-61　2020/05
Publisher: The Magnetics Society of Japan
DOI： 10.20819/msjtmsj.20TR403 　

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 A prediction method for taking deterioration of silicon steel sheet due to machining process is essential to improve the performance of electric machines. In a previous paper, it was demonstrated that simplified Landau-Lifshitz-Gilbert (LLG) equation can predict magnetic properties of silicon steel sheet rolled with different thickness reductions. However, further improvement of calculation accuracy of magnetic properties of heavy rolled silicon steel sheet is required. This paper presents the improved method using the simplified LLG equation for predicting magnetic properties of heavy rolled silicon steel sheet. The validity of the proposed method is proved by comparing with measured values.
Characteristics of Interior Permanent Magnet Magnetic Gear made of Amorphous Alloy Peer-reviewed

Mizuana Y., Nakamura K., Suzuki Y., Oishi Y., Tachiya Y., Kuritani K.

Transaction of the Magnetics Society of Japan Special Issues　4　(1)　52-56　2020/05
Publisher: The Magnetics Society of Japan
DOI： 10.20819/msjtmsj.20TR402 　

eISSN： 2432-0471

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Magnetic gears can transmit torque without any mechanical contacts. Hence, vibration and acoustic noise caused thereby are very low, and maintainability is high. Various types of magnetic gears have been proposed. Among them, a flux-modulated type magnetic gear has higher torque density in comparison with conventional magnetic gears. In a previous paper, an interior permanent magnet (IPM) flux-modulated type magnetic gear was proposed in order to reduce eddy current loss in the magnets. However, reduction of iron loss is also important to further improve the efficiency. This paper discusses characteristics of the IPM magnetic gear made of amorphous alloy by using finite element method (FEM). In addition, the prototyped gear is tested. The results reveal that amorphous alloy contributes to improve both efficiency and torque.
高周波で励磁される高効率鉄心に適した磁気回路モデル Peer-reviewed

畠山智行, 中村健二

日本磁気学会論文特集号　4　(1)　46-51　2020/05

DOI： 10.20819/msjtmsj.20TR401 　
Loss reduction of outer-rotor type high-speed interior permanent magnet motors Peer-reviewed

S. Sakurai, K. Nakamura

International Journal of Applied Electromagnetics and Mechanics　1-1　2020

DOI： 10.3233/JAE-209399 　
Development of spoke-type IPM magnetic gear Peer-reviewed

Y. Mizuana, K. Nakamura, Y. Suzuki, Y. Oishi, Y. Tachiya, K. Kuritani

International Journal of Applied Electromagnetics and Mechanics　64　(1-4)　1-1　2020

DOI： 10.3233/JAE-209389 　

ISSN： 1383-5416

eISSN： 1875-8800
Development of in-wheel magnetic-geared motor for walking support machines Peer-reviewed

K. Ito, T. Kadomatsu, K. Obana, K. Nakamura

International Journal of Applied Electromagnetics and Mechanics　1-1　2020

DOI： 10.3233/JAE-209318 　
500 kVA medium-frequency core-type amorphous transformers with alternately wound sheet winding for offshore DC grid Peer-reviewed

Kurita, N., Hatakeyama, T., Kimura, M., Nakamura, K., Ichinokura, O.

IEEJ Journal of Industry Applications　8　(5)　756-766　2019/09/01
Publisher: Institute of Electrical Engineers of Japan (IEE Japan)
DOI： 10.1541/ieejjia.8.756 　

ISSN： 2187-1094

eISSN： 2187-1108
Reluctance Network Model of Three-Phase-Laminated-Core Variable Inductor Considering Magnetic Hysteresis Behavior Peer-reviewed

Hane, Y., Nakamura, K., Ohinata, T., Arimatsu, K.

IEEE Transactions on Magnetics　55　(7)　8401306　2019/07

DOI： 10.1109/TMAG.2019.2900527 　

ISSN： 0018-9464

eISSN： 1941-0069
Efficiency Improvement of In-Wheel Magnetic Geared Motor and Feasibility Study for Walking Support Machines Peer-reviewed

Koki Ito, Takahisa Kadomatsu, Kenji Nakamura

2019 IEEE International Electric Machines & Drives Conference (IEMDC)　2019/05
Publisher: IEEE
DOI： 10.1109/iemdc.2019.8785161 　
Prediction Method of Magnetic Properties in Magnetic Core due to Machining Process by Using LLG Equation Peer-reviewed

Y. Hane, K. Nakamura, T. Yoshioka, T. Kawase, T. Ishikawa

Transaction of the Magnetics Society of Japan Special Issues　3　(1)　90-94　2019/05
Publisher: The Magnetics Society of Japan
DOI： 10.20819/msjtmsj.19TR318 　

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 An analytical method taking deterioration of magnetic core due to machining process into consideration and finding the optimum processing method are essential to development of high-efficiency electric machines. In a previous paper, simplified Landau-Lifshitz-Gilbert (LLG) equation, which expresses the behavior of magnetizations inside the magnetic core, was used for calculating magnetic properties of the electromagnetic steel sheet. It was demonstrated that the proposed method can express the dynamic behavior of the magnetic core including manor loops. This paper presents a novel prediction method of magnetic properties in the machined magnetic core by using the simplified LLG equation.
Torque and Efficiency Improvement of High-Speed Cooling-Fan Motor Peer-reviewed

K. Kawamura, K. Nakamura, O. Ichinokura, H. Goto, H. J. Guo

Transaction of the Magnetics Society of Japan Special Issues　3　(1)　85-89　2019/05

DOI： 10.20819/msjtmsj.19TR317 　
Performance Improvement of Interior Permanent Magnet Magnetic Gear Peer-reviewed

Y. Mizuana, K. Nakamura, Y. Suzuki, Y. Oishi, Y. Tachiya, K. Kuritani

Transaction of the Magnetics Society of Japan Special Issues　3　(1)　74-78　2019/05
Publisher: The Magnetics Society of Japan
DOI： 10.20819/msjtmsj.19TR315 　

eISSN： 2432-0471

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Magnetic gears can change the speed and torque without any mechanical contacts. Therefore, it has a low vibration and acoustic noise, and maintenance-free operation. Several kinds of magnetic gears were proposed. Among them, a flux-modulated type magnetic gear has higher torque density than other kinds of magnetic gears. In a previous paper, an interior permanent magnet (IPM) structure was presented. It was demonstrated by finite element analysis (FEM) that eddy current loss in the magnets can be reduced remarkably. This paper describes the comparison of the IPM structure with surface permanent magnet (SPM) structure in experiment and discusses a performance improvement of the IPM gear from the view point of the rotor structure.
Efficiency Improvement of In-Wheel Magnetic-Geared Motor for Walking Support Machines Peer-reviewed

K. Ito, T. Kadomatsu, K. Nakamura

Transaction of the Magnetics Society of Japan Special Issues　3　(1)　69-73　2019/05
Publisher: IEEE
DOI： 10.20819/msjtmsj.19TR314 　
Calculation of Eddy Current Loss on Rotor Surface of Field-Winding type Claw-Pole Motor based on Reluctance Network Analysis Peer-reviewed

Y. Ichikawa, K. Nakamura

Transaction of the Magnetics Society of Japan Special Issues　3　(1)　64-68　2019/05

DOI： 10.20819/msjtmsj.19TR313 　
Prototype Tests of Transverse-Flux-Type SR Motor and Characteristics Improvement Peer-reviewed

T. Komoriya, Y. Ito, K. Nakamura

Transaction of the Magnetics Society of Japan Special Issues　3　(1)　58-63　2019/05

DOI： 10.20819/msjtmsj.19TR312 　
Recent topics of loss analysis of power magnetics devices based on equivalent circuit method,等価回路法に基づく電力用磁気デバイスの損失解析の研究動向 Peer-reviewed

Nakamura, K., Morita, T., Yoshida, Y.

IEEJ Transactions on Fundamentals and Materials　138　(12)　585-591　2018/12

DOI： 10.1541/ieejfms.138.585 　
Recent topics of applied magnetic technologies in power generation system,発電システムにおける磁気応用技術の研究動向 Peer-reviewed

Ueno, T., Nakamura, K.

IEEJ Transactions on Fundamentals and Materials　138　(12)　599-604　2018/12

DOI： 10.1541/ieejfms.138.599 　
Efficiency improvement of magnetic-geared motor by open-slot and interior permanent magnet structure

K. Nakamura, T. Kadomatsu, Y. Hane

2018 IEEE International Magnetic Conference, INTERMAG 2018　2018/10/24
Publisher: Institute of Electrical and Electronics Engineers Inc.
DOI： 10.1109/INTMAG.2018.8508790 　
Reluctance Network Model of Permanent Magnet Synchronous Motor Considering Magnetic Hysteresis Behavior Peer-reviewed

Y. Hane, K. Nakamura

Proceedings of 2018 IEEE International Magnetics Conference (INTERMAG 2018),　1800038　2018/10

DOI： 10.1109/INTMAG.2018.8508115 　
Basic Examination of Electromagnetic and Thermal Coupled Analysis for Permanent Magnet Motor based on Reluctance Network Analysis Peer-reviewed

K. Nakamura, K. Kawamura

Transaction of the Magnetics Society of Japan Special Issues　2　(1)　33-36　2018/05

DOI： 10.20819/msjtmsj.18TR208 　
Performance Calculation of Field-Winding type Claw-Pole Motor based on Reluctance Network Analysis Peer-reviewed

Y. Ichikawa, K. Nakamura, J. Sukhwa, N. Kurimoto

Transaction of the Magnetics Society of Japan Special Issues　2　(1)　29-32　2018/05

DOI： 10.20819/msjtmsj.18TR207 　
Hysteresis Modeling for Reluctance Network Analysis Peer-reviewed

Y. Hane, H. Tanaka, K. Nakamura

Transaction of the Magnetics Society of Japan Special Issues　2　(1)　25-28　2018/05
Publisher: The Magnetics Society of Japan
DOI： 10.20819/msjtmsj.18TR206 　

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 Quantitative estimation of iron loss taking magnetic hysteresis behavior into account is essential to development of high-efficient electrical machines. In our previous papers, we proposed and examined a magnetic circuit model incorporating a play model derived by LLG (Landau-Lifshitz-Gilbert) equation. In this model, dc hysteresis is expressed by the play model which was preliminary obtained from the LLG equation, while ac hysteresis is expressed by magnetic circuit elements. It was proved that the proposed magnetic circuit model can calculate both major and minor hysteresis loops of a ring-core with high accuracy in a short time. In this paper, in order to apply the proposed method for more complicated machines such as electric motors and generators, a novel reluctance network analysis (RNA) model incorporating the play model is presented.
Hysteresis Modeling of Magnetic Devices Based on Reluctance Network Analysis

Y. Hane, K. Nakamura

IPEC-Niigata 2018　23D2-1-2429　2018/05

DOI： 10.23919/IPEC.2018.8507646 　

ISSN： 2150-6078
A Novel 3-D Concentric-Winding-Type Three-Phase Variable Inductor for Reactive Power Compensation in Electric Power Systems Peer-reviewed

Nakamura, K., Yamada, Y., Nono, R., Ohinata, T., Arimatsu, K., Ichinokura, O.

IEEE Transactions on Magnetics　53　(11)　2600204　2017/11

DOI： 10.1109/TMAG.2017.2717479 　

ISSN： 0018-9464

eISSN： 1941-0069
A novel three-dimensional concentric-winding type three-phase variable inductor for reactive power compensation in electric power systems Peer-reviewed

K. Nakamura, Y. Yamada, R. Nono, T. Ohinata, K. Arimatsu, O. Ichinokura

2017 IEEE International Magnetics Conference, INTERMAG 2017　2017/08/10
Publisher: Institute of Electrical and Electronics Engineers Inc.
DOI： 10.1109/INTMAG.2017.8007682 　
Analysis of Dynamic Characteristics of Full-Pitch-Winding Switched Reluctance Motor Based on Reluctance Network Analysis Peer-reviewed

Ishikawa, T., Ikebuchi, K., Nakamura, K., Ichinokura, O., Kurimoto, N., Nishijima, Y.

SAE Technical Papers　2017-March　(March)　2017-01-1250　2017/03/28
Publisher: SAE International
DOI： 10.4271/2017-01-1250 　

ISSN： 0148-7191
Unified Calculation Method for Motor Torque in Reluctance Network Analysis Peer-reviewed

Nakamura, K., Ichinokura, O.

Electrical Engineering in Japan (English translation of Denki Gakkai Ronbunshi)　198　(1)　25-33　2017/01

DOI： 10.1002/eej.22877 　

ISSN： 0424-7760

eISSN： 1520-6416
Design and Prototyping of 100 kVA Concentric-Winding type Three-Phase Variable Inductor based on Reluctance Network Analysis Peer-reviewed

K. Nakamura, Y. Yamada, T. Ohinata, K. Arimatsu, M. Yamada, M. Takiguchi, T. Kojima, O. Ichinokura

Transaction of the Magnetics Society of Japan Special Issues　1　(1)　40-43　2017/01
Publisher: The Magnetics Society of Japan
DOI： 10.20819/msjtmsj.17TR109 　

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 Variable inductors consist of a magnetic core and primary dc and secondary ac windings. The effective inductance of the secondary ac winding can be controlled quickly and continuously by the primary dc current due to a magnetic saturation effect. Thus, the variable inductors can be applied as a reactive power compensator in electric power systems. The variable inductors have several desirable features including a simple and robust structure, low cost, and high reliability. In a previous paper, a concentric-winding type three-phase variable inductor was proposed, and it was demonstrated that the proposed variable inductor had good controllability and a low distortion current. This paper describes the design of a 6.6 kV-100 kVA concentric-winding type three-phase variable inductor based on reluctance network analysis (RNA) and reports the results of prototype testing.
Eddy Current Loss Analysis for Soft Magnetic Composite Considering Magnetic Particles Peer-reviewed

I. Masui, K. Nakamura, O. Ichinokura

Transaction of the Magnetics Society of Japan Special Issues　1　(1)　53-56　2017/01
Publisher: The Magnetics Society of Japan
DOI： 10.20819/msjtmsj.17TR111 　

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 Soft magnetic composite (SMC) is an artificial aggregate of magnetic particles that are electrically isolated by resin coating on the particles. This isolation enables it to suppress eddy current flowing inter-particles, and thereby its iron loss at high frequency is very low compared with that of conventional silicon steel. This paper presents an analysis model of the SMC including the magnetic particles in order to accurately predict the SMC performance. Experimental results show that the calculation accuracy of the iron loss of the SMC is improved by considering the magnetic particles with its isolated coating. Moreover, the proposed model clarifies that the inter-particle eddy current loss becomes dominant when the particle size is gradually decreased; that is, the effect of reducing iron loss by finer particle size is basically limited.
Development of High-Speed Switched Reluctance Motor for Electric Power Tools Peer-reviewed

Kenji Nakamura, Yuya Kumasaka, Osamu Ichinokura

8TH JOINT EUROPEAN MAGNETIC SYMPOSIA (JEMS2016)　903　012040　2017

DOI： 10.1088/1742-6596/903/1/012040 　

ISSN： 1742-6588
Accuracy Improvement of Magnetic Hysteresis Calculated by LLG Equation Peer-reviewed

H. Tanaka, K. Nakamura, O. Ichinokura

8TH JOINT EUROPEAN MAGNETIC SYMPOSIA (JEMS2016)　903　012048　2017

DOI： 10.1088/1742-6596/903/1/012048 　

ISSN： 1742-6588
Magnetic Circuit Model combined with Play Model Obtained from Landau-Lifshitz-Gilbert Equation Peer-reviewed

H. Tanaka, K. Nakamura, O. Ichinokura

8TH JOINT EUROPEAN MAGNETIC SYMPOSIA (JEMS2016)　903　012047　2017

DOI： 10.1088/1742-6596/903/1/012047 　

ISSN： 1742-6588
Iron Loss Calculation for Concentric-Winding Type Three-Phase Variable Inductor based on Reluctance Network Analysis Peer-reviewed

K. Nakamura, Y. Yamada, T. Ohinata, K. Arimatsu, T. Kojima, M. Yamada, R. Matsumoto, M. Takiguchi, O. Ichinokura

Journal of the Magnetics Society of Japan　40　(3)　67-70　2016/05
Publisher: The Magnetics Society of Japan
DOI： 10.3379/msjmag.1603R003 　

ISSN： 1882-2924

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A variable inductor consisting of just a magnetic core and primary dc and secondary ac windings, is able to control effective inductance of the secondary ac winding linearly and continuously by the primary dc current due to magnetic saturation effect. Therefore, it can be applied as a var compensator in electric power systems. The variable inductor has desirable features such as simple and robust structure, low cost, and high reliability. In a previous paper, a novel concentric-winding type three-phase variable inductor was proposed. It was demonstrated in experiments that the proposed variable inductor has good controllability and low distortion current. This paper presents a method for calculating iron loss of the proposed variable inductor based on reluctance network analysis (RNA). The validity of the proposed method is demonstrated through a comparison with measured values.
洋上風力発電用直流送電システムに関する基礎検討

藤井孝紀, 中村健二, 一ノ倉理, 岡本達希

電気関係学会東北支部連合大会講演論文集　2016　83-83　2016
Publisher: 電気関係学会東北支部連合大会実行委員会
DOI： 10.11528/tsjc.2016.0_83 　
埋込磁石型磁気ギヤードモータに関する基礎検討

門松孝尚, 中村健二, 一ノ倉理

電気関係学会東北支部連合大会講演論文集　2016　246-246　2016
Publisher: 電気関係学会東北支部連合大会実行委員会
DOI： 10.11528/tsjc.2016.0_246 　
リラクタンスネットワーク解析による全節巻SRモータの動解析

池淵耕平, 中村健二, 一ノ倉理, 石川智一

電気関係学会東北支部連合大会講演論文集　2016　247-247　2016
Publisher: 電気関係学会東北支部連合大会実行委員会
DOI： 10.11528/tsjc.2016.0_247 　
Development of Concentric-Winding Type Three-Phase Variable Inductor Peer-reviewed

Kenji Nakamura, Koya Honma, Takashi Ohinata, Kenji Arimatsu, Takehiko Kojima, Makoto Yamada, Ryohei Matsumoto, Masaya Takiguchi, Osamu Ichinokura

IEEE TRANSACTIONS ON MAGNETICS　51　(11)　2015/11

DOI： 10.1109/TMAG.2015.2441556 　

ISSN： 0018-9464

eISSN： 1941-0069
Unified calculation method for motor Torque in reluctance network analysis Peer-reviewed

Kenji Nakamura, Osamu Ichinokura

IEEJ Transactions on Industry Applications　135　(11)　1063-1069　2015/11/01
Publisher: Institute of Electrical Engineers of Japan
DOI： 10.1541/ieejias.135.1063 　

ISSN： 1348-8163 0913-6339
Operation principle and basic characteristics of VR magnetic gear Peer-reviewed

Hidenori Kato, Tatsuya Tonari, Michinari Fukuoka, Kenji Nakamura

IEEJ Transactions on Industry Applications　135　(11)　1100-1106　2015/11/01
Publisher: Institute of Electrical Engineers of Japan
DOI： 10.1541/ieejias.135.1100 　

ISSN： 1348-8163 0913-6339
Magnetic Circuit Model Considering Magnetic Hysteresis Peer-reviewed

Hideaki Tanaka, Kenji Nakamura, Osamu Ichinokura

ELECTRICAL ENGINEERING IN JAPAN　192　(3)　11-18　2015/08

DOI： 10.1002/eej.22733 　

ISSN： 0424-7760

eISSN： 1520-6416
Design for size and weight reduction of lap-winding type three-phase variable inductor Peer-reviewed

Nakamura, K., Honma, K., Ohinata, T., Arimatsu, K., Ichinokura, O.

Journal of Applied Physics　117　(17)　17D523　2015/05

DOI： 10.1063/1.4919118 　

ISSN： 0021-8979

eISSN： 1089-7550
Calculation of Iron Loss in Soft Ferromagnetic Materials using Magnetic Circuit Model Taking Magnetic Hysteresis into Consideration Peer-reviewed

H. Tanaka, K. Nakamura, O. Ichinokura

Journal of the Magnetics Society of Japan　39　(2)　65-70　2015/03
Publisher: The Magnetics Society of Japan
DOI： 10.3379/msjmag.1501R001 　

ISSN： 1882-2924

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The establishment of a simple and practical method of calculating iron loss, including magnetic hysteresis behavior, in electric machines has recently been required in order to develop highly efficient machines quickly and at low cost. A novel and practical method of calculating hysteresis behavior based on a magnetic circuit model incorporated with the Landau-Lifshitz-Gilbert (LLG) equation was proposed in a previous paper. The proposed method enabled highly accurate calculation of the hysteresis loops of conventional non-oriented Si steel under sinusoidal and pulse width modulation (PWM) wave excitations. In this paper, we prove the usefulness and versatility of the proposed method by reporting our recent calculations of the hysteresis loops of two other types of soft ferromagnetic materials (low-loss Si steel with thickness of 0.2 mm and an amorphous core). The calculated results were compared with those obtained from an experiment.
大容量洋上風力発電システムの動作シミュレーションに関する基礎検討

高橋拓暉, 中村健二, 一ノ倉理

電気関係学会東北支部連合大会講演論文集　2015　149-149　2015
Publisher: 電気関係学会東北支部連合大会実行委員会
DOI： 10.11528/tsjc.2015.0_149 　
熱抵抗回路網による表面磁石モータの温度解析

菅井悠史, 中村健二, 一ノ倉理

電気関係学会東北支部連合大会講演論文集　2015　56-56　2015
Publisher: 電気関係学会東北支部連合大会実行委員会
DOI： 10.11528/tsjc.2015.0_56 　
Development of Concentric-Winding Type Three-Phase Variable Inductor Peer-reviewed

Nakamura, K., Honma, K., Ohinata, T., Arimatsu, K., Kojima, T., Yamada, M., Matsumoto, R., Takiguchi, M., Ichinokura, O.

IEEE Transactions on Magnetics　51　(11)　8402104　2015

DOI： 10.1109/TMAG.2015.2441556 　
Basic Consideration of Winding Arrangement of Amorphous Transformers for MW-class DC-DC converters Peer-reviewed

H. Tanaka, K. Nakamura, O. Ichinokura

2015 IEEE MAGNETICS CONFERENCE (INTERMAG)　40　(2)　35-38　2015

DOI： 10.3379/msjmag.1602R004 　
Basic Characteristics of In-Wheel Magnetic-geared Motors Peer-reviewed

K. Nakamura, K. Akimoto, T. Takemae, O. Ichinokura

Journal of the Magnetics Society of Japan　39　(1)　29-32　2015/01
Publisher: The Magnetics Society of Japan
DOI： 10.3379/msjmag.1412R006 　

ISSN： 1882-2924

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This paper presents a feasibility study of an in-wheel magnetic-geared motor for walking support machines. The proposed magnetic-geared motor consists of an axial-gap permanent magnet (PM) motor and a magnetic gear. Axial-gap PM motors generally have larger torque than conventional radial-gap motors when their structures are flat like those in in-wheel motors. Moreover, the axial-gap PM motor was combined with magnetic gears since the in-wheel motor requires further large torque at low speed. The characteristics and usefulness of the proposed magnetic-geared motor are demonstrated through experiments and analysis conducted using finite element method (FEM).
A Novel Flux-Modulated Type Dual-Axis Motor for Hybrid Electric Vehicles Peer-reviewed

Michinari Fukuoka, Kenji Nakamura, Hidenori Kato, Osamu Ichinokura

IEEE TRANSACTIONS ON MAGNETICS　50　(11)　8202804　2014/11

DOI： 10.1109/TMAG.2014.2327646 　

ISSN： 0018-9464

eISSN： 1941-0069
A Consideration of High-Speed SR Motor for Electric Power Tools Peer-reviewed

K. Isobe, K. Nakamura, O. Ichinokura

Journal of the Magnetics Society of Japan　38　(5)　194-198　2014/09
Publisher: The Magnetics Society of Japan
DOI： 10.3379/msjmag.1409R001 　

ISSN： 1882-2924

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A switched reluctance (SR) motor consists of only laminated-core and windings. The concentrated windings are coiled around each stator pole. The rotor is only made of laminated-core, while it has neither permanent magnets nor windings. Hence, the SR motor has simple and robust structure, low cost, and maintenance-free operation. It is expected to be put into various fields, especially to high-speed application. This paper presents the SR motor which is suitable for electric power tools. First, an SR motor which has the same specifications as a permanent magnet (PM) motor used in a present electric power tool is designed and compared. Next, an improved SR motor which has the optimum shape and size, and winding specifications is presented. It is proved that the performance of the improved SR motor is almost comparable to the present PM motor.
Basic Characteristics of Lap-Winding type Three-Phase Laminated-Core Variable Inductor Peer-reviewed

K. Nakamura, K. Honma, T. Ohinata, K. Arimatsu, T. Shirasaki, O. Ichinokura

Journal of the Magnetics Society of Japan　38　(4)　174-177　2014/07
Publisher: The Magnetics Society of Japan
DOI： 10.3379/msjmag.1407R003 　

ISSN： 1882-2924

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Variable inductors, which are composed of only a magnetic core and primary dc and secondary ac windings, can control the effective inductance of the secondary ac winding linearly and continuously by primary dc current due to the magnetic saturation effect. The variable inductors have simple and robust structures, and are highly reliable. Therefore, they are suitable for application as Var compensators in electric power systems. We previously proposed a three-phase laminated-core variable inductor specialized for electric power systems. It had only one laminated-core in which the three-phase secondary ac windings were installed together, in order to reduce the size and weight in comparison with conventional single-phase variable inductors. We propose here a lap-winding type three-phase laminated-core variable inductor that achieves further reduction in size and weight. Basic characteristics of the proposed variable inductor were calculated using finite element method (FEM) and reluctance network analysis (RNA).
Performance improvement of magnetic gear and efficiency comparison with conventional mechanical gear Peer-reviewed

Kenji Nakamura, Michinari Fukuoka, Osamu Ichinokura

JOURNAL OF APPLIED PHYSICS　115　(17)　17A314　2014/05

DOI： 10.1063/1.4863809 　

ISSN： 0021-8979

eISSN： 1089-7550
Experimental Evaluation of Characteristics of SR Motor Made of Permendur Peer-reviewed

Yu Hasegawa, Kenji Nakamura, Osamu Ichinokura

ELECTRICAL ENGINEERING IN JAPAN　187　(1)　51-57　2014/04

DOI： 10.1002/eej.22431 　

ISSN： 0424-7760

eISSN： 1520-6416
Evaluation of influence of carrier harmonics of SPM motor based on reluctance network analysis Peer-reviewed

Yukihiro Yoshida, Kenji Nakamura, Osamu Ichinokura

IEEJ Journal of Industry Applications　3　(4)　304-309　2014
Publisher: Institute of Electrical Engineers of Japan
DOI： 10.1541/ieejjia.3.304 　

ISSN： 2187-1108 2187-1094
Improvements to Efficiency and Reduced Torque Ripple in Axial-Gap PM Motors Peer-reviewed

T. Takemae, K. Nakamura, O. Ichinokura

Journal of the Magnetics Society of Japan　38　(1)　15-19　2014/01
Publisher: The Magnetics Society of Japan
DOI： 10.3379/msjmag.1312R004 　

ISSN： 1882-2924

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Axial-gap permanent magnet (PM) motors have an air gap in the axial direction and produce more torque than conventional radial-gap motors, especially with flat structures. However, eddy-current loss in the magnets cannot be disregarded since axial-gap PM motors generally have a surface permanent magnet (SPM) rotor and an open slot structure. Furthermore, the open slot structure causes large amounts of torque ripple. We report here a method for decreasing the eddy-current loss by mounting a soft magnetic composite (SMC) onto the magnets. We also propose a method for reducing the torque ripple by adjusting both the pole arc angle of the magnets and the spatial phase difference between the two rotors.
Magnetic circuit model considering magnetic hysteresis Peer-reviewed

Hideaki Tanaka, Kenji Nakamura, Osamu Ichinokura

IEEJ Transactions on Fundamentals and Materials　134　(4)　243-249　2014
Publisher: Institute of Electrical Engineers of Japan
DOI： 10.1541/ieejfms.134.243 　

ISSN： 1347-5533 0385-4205
Influence of pole-pieces on characteristics in planetary type magnetic gear Peer-reviewed

Michinari Fukuoka, Kenji Nakamura, Osamu Ichinokura

IEEJ Transactions on Fundamentals and Materials　134　(6)　6-421　2014
Publisher: Institute of Electrical Engineers of Japan
DOI： 10.1541/ieejfms.134.416 　

ISSN： 1347-5533 0385-4205
Efficiency optimization of SPM motor considering carrier harmonics based on electric and magnetic networks Peer-reviewed

Yukihiro Yoshida, Kenji Nakamura, Osamu Ichinokura, Katsubumi Tajima

IEEJ Journal of Industry Applications　3　(6)　422-427　2014
Publisher: Institute of Electrical Engineers of Japan
DOI： 10.1541/ieejjia.3.422 　

ISSN： 2187-1108 2187-1094
Development of 72/96-pole rare-earth free permanent magnet reluctance generator for small-scale renewable power generation Peer-reviewed

Kenji Nakamura, Erkan Sunan, Osamu Ichinokura

IEEJ Journal of Industry Applications　3　(1)　41-46　2014
Publisher: Institute of Electrical Engineers of Japan
DOI： 10.1541/ieejjia.3.41 　

ISSN： 2187-1108 2187-1094
Magnetic-Circuit-Based Iron Loss Estimation Under Square Wave Excitation With Various Duty Ratios Peer-reviewed

Kenji Nakamura, Kentaro Fujita, Osamu Ichinokura

IEEE TRANSACTIONS ON MAGNETICS　49　(7)　3997-4000　2013/07

DOI： 10.1109/TMAG.2013.2240267 　

ISSN： 0018-9464

eISSN： 1941-0069
RNA-Based Optimum Design method for SPM type Magnetic Gears Peer-reviewed

M. Fukuoka, K. Nakamura, O. Ichinokura

Journal of the Magnetics Society of Japan　37　(3-2)　264-267　2013/05
Publisher:
DOI： 10.3379/msjmag.1212R001 　

ISSN： 1882-2924
Eddy Current Loss Calculation in Permanent Magnet of SPM Motor Including Carrier Harmonics Based on Reluctance Network Analysis Peer-reviewed

Y. Yoshida, K. Nakamura, O. Ichinokura

Journal of the Magnetics Society of Japan　37　(3-2)　278-281　2013/05
Publisher:
DOI： 10.3379/msjmag.1301R009 　

ISSN： 1882-2924
Basic Characteristics of Three-dimensional Three-phase Variable Inductor Peer-reviewed

K. Nakamura, M. Nagao, T. Ohinata, T. Shirasaki, O. Ichinokura

Journal of the Magnetics Society of Japan　37　(2)　35-38　2013/03/01
Publisher: The Magnetics Society of Japan
DOI： 10.3379/msjmag.1303R001 　

ISSN： 1882-2924

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Variable inductors, which consist of magnetic core and primary dc and secondary ac windings, can continuously control effective inductance of secondary ac winding by using primary dc current due to the magnetic saturation effect. Variable inductors have advantageous features such as their simple and robust structures, and they are extremely reliable. Therefore, they are suitable in applications as reactive power compensators in electric power systems. A three-phase laminated-core variable inductor was proposed in a previous paper that reduced size and weight more than those in conventional single-phase variable inductors. A novel three-dimensional three-phase variable inductor designed to further reduce size and weight and to improve manufacturing capabilities is presented here. The basic characteristics of the proposed variable inductor were calculated through reluctance network analysis (RNA) and the finite element method (FEM).
Consideration of Magnetic Circuit Model Incorporating LLG Equation Peer-reviewed

H. Tanaka, K. Nakamura, O. Ichinokura

Journal of the Magnetics Society of Japan　37　(2)　39-43　2013/03/01
Publisher: The Magnetics Society of Japan
DOI： 10.3379/msjmag.1303R003 　

ISSN： 1882-2924

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The development of highly-efficient machines has recently been urgently required from the viewpoint of conserving energy and protecting the environment. Therefore, a method of quantitative analysis that can be used to calculate core loss with a high degree of high accuracy is necessary. This paper presents a novel model for a magnetic circuit that incorporates the Landau-Lifshitz-Gilbert (LLG) equation. The model consists of two elements. The first is a dc hysteresis element given by the LLG equation, and the second is an inductance element that denotes eddy current loss in iron steel sheets. The proposed model can be used to estimate the dynamic behavior of voltage, current, and flux by coupling it with an external model of an electric circuit. The validity of the proposed method was proved by comparing it with cataloged values.
Consideration of Anomalous Eddy Current Loss in Magnetic Circuit Peer-reviewed

K. Fujita, K. Nakamura, O. Ichinokura

Journal of the Magnetics Society of Japan　37　(2)　44-47　2013/03/01
Publisher: The Magnetics Society of Japan
DOI： 10.3379/msjmag.1303R002 　

ISSN： 1882-2924

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In recent years, a quantitative analysis method for electric machines is strongly required, especially iron loss calculation with high accuracy is very important to develop the high-efficiency machines. This paper presents a method for calculating iron loss of electric machines based on magnetic circuit method. The proposed magnetic circuit consists of three elements as follows: a dependent source which expresses dc hysteresis of core material, an inductance which denotes eddy current loss, and a dependent source which represents anomalous eddy current loss. These elements can be simply obtained from dc hysteresis loops and core loss curves of core material. The validity of the proposed method is proved by comparing with measured values.
Characteristics of the SR Motor with Auxiliary Windings and Permanent Magnets in Generating Mode Peer-reviewed

Y. Hasegawa, K. Nakamura, O. Ichinokura

Journal of the Magnetics Society of Japan　37　(1)　12-15　2013/01/01
Publisher:
DOI： 10.3379/msjmag.1211R002 　

ISSN： 1882-2924
Calculation of eddy current loss in permanent magnet motor caused by carrier harmonics based on reluctance network analysis

Yukihiro Yoshida, Kenji Nakamura, Osamu Ichinokura

2013 15th European Conference on Power Electronics and Applications, EPE 2013　170　2013

DOI： 10.1109/EPE.2013.6631849 　
Iron loss calculation by incorporating LLG equation into magnetic circuit model

Hideaki Tanaka, Kenji Nakamura, Osamu Ichinokura

2013 15th European Conference on Power Electronics and Applications, EPE 2013　190　2013

DOI： 10.1109/EPE.2013.6631860 　
Loss analysis and performance improvement of trial SPM type magnetic gear

Michinari Fukuoka, Kenji Nakamura, Osamu Ichinokura

2013 15th European Conference on Power Electronics and Applications, EPE 2013　554　2013

DOI： 10.1109/EPE.2013.6634388 　
Development of high torque density axial-gap switched reluctance motor for in-wheel direct-drive EV

Hiroki Goto, Toru Shibamoto, Kenji Nakamura, Osamu Ichinokura

2013 15th European Conference on Power Electronics and Applications, EPE 2013　589　2013

DOI： 10.1109/EPE.2013.6634413 　
Super-Multipolar Permanent Magnet Reluctance Generator Designed for Small-Scale Wind-Turbine Generation Peer-reviewed

Kenji Nakamura, Osamu Ichinokura

IEEE TRANSACTIONS ON MAGNETICS　48　(11)　3311-3314　2012/11

DOI： 10.1109/TMAG.2012.2198441 　

ISSN： 0018-9464
Consideration of Eddy Current Loss Estimation in SPM Motor Based on Electric and Magnetic Networks Peer-reviewed

Yukihiro Yoshida, Kenji Nakamura, Osamu Ichinokura

IEEE TRANSACTIONS ON MAGNETICS　48　(11)　3108-3111　2012/11

DOI： 10.1109/TMAG.2012.2200236 　

ISSN： 0018-9464
A Novel Switched Reluctance Motor With the Auxiliary Windings and Permanent Magnets Peer-reviewed

Yu Hasegawa, Kenji Nakamura, Osamu Ichinokura

IEEE TRANSACTIONS ON MAGNETICS　48　(11)　3855-3858　2012/11

DOI： 10.1109/TMAG.2012.2197734 　

ISSN： 0018-9464
SR Motor having Permanent Magnets and Windings in the Stator Yoke Peer-reviewed

Y. Hasegawa, K. Nakamura, O. Ichinokura

Journal of the Magnetics Society of Japan　36　(3)　245-248　2012/05/01
Publisher: The Magnetics Society of Japan
DOI： 10.3379/msjmag.1203R005 　

ISSN： 1882-2924

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The switched reluctance (SR) motor is low cost, extremely robust, and has a wide range of variable speeds. However, its power density is generally inferior in comparison with conventional permanent magnet (PM) motors. This paper presents a novel SR motor that has auxiliary windings and permanent magnets in the stator yoke. It operates similarly to a conventional SR motor in the motoring mode. On the contrary, it operates as a permanent magnet reluctance generator (PMRG) in the generating mode. The basic characteristics of the proposed SR apparatus operating as a motor and generator were calculated by using the finite element method (FEM), and compared with those of conventional reluctance machines.
Basic Characteristics of 18-leg Three-Phase Laminated-Core Variable Inductor Peer-reviewed

M. Nagao, K. Nakamura, O. Ichinokura

Journal of the Magnetics Society of Japan　36　(3)　253-257　2012/05/01
Publisher: The Magnetics Society of Japan
DOI： 10.3379/msjmag.1205R015 　

ISSN： 1882-2924

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Variable inductors, which are composed of only a magnetic core and primary dc and secondary ac windings, can control the effective inductance of the secondary ac winding linearly and continuously by the primary dc current due to the effect of magnetic saturation. Variable inductors have advantageous features such as having a simple, and robust structure, and high reliability. Therefore, they can be applied as var compensators in electric power systems. A 6-leg three-phase laminated-core variable inductor was proposed in a previous paper. It had only one laminated-core in which three-phase secondary ac windings were installed, to reduce its size and weight in comparison with conventional single-phase variable inductors. A 18-leg three-phase-laminated-core variable inductor is proposed in this paper to further reduce size and weight. The basic characteristics of the proposed variable inductor were calculated based on reluctance network analysis (RNA).
Examination of Magnetic Gear using Polar Anisotropic Bonded Magnet Peer-reviewed

M. Fukuoka, K. Nakamura, O. Ichinokura

Journal of the Magnetics Society of Japan　36　(2)　123-126　2012/03/01
Publisher: The Magnetics Society of Japan
DOI： 10.3379/msjmag.1204R001 　

ISSN： 1882-2924

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Magnetic gears can transmit torque without mechanical contact. They therefore have low vibration and acoustic noise, and are low maintenance in comparison with conventional mechanical gears. Various types of magnetic gears have been introduced. A planetary type magnetic gear has attracted interest recently because of its higher transmission torque compared to other types, and it is expected to be put into practical use. However, it is necessary to reduce the eddy current loss caused by harmonic fluxes in the air gap. This paper presents a magnetic gear using polar anisotropic Nd-Fe-B bonded magnets in which the eddy current is rarely induced.
A Method for Calculating Eddy Current Loss Distribution Considering Magnetic Reaction Field Based on Reluctance Network Analysis Peer-reviewed

Y. Yoshida, K. Nakamura, O. Ichinokura

Journal of the Magnetics Society of Japan　36　(2)　127-130　2012/03/01
Publisher: The Magnetics Society of Japan
DOI： 10.3379/msjmag.1204R002 　

ISSN： 1882-2924

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A reluctance network analysis (RNA) model of a permanent magnet (PM) motor was presented in a previous paper and the iron loss of the stator core of the PM motor was accurately calculated by using this model. However, loss of eddy current in permanent magnets caused by carrier harmonics and slot harmonics was not discussed. This paper presents a method of calculating eddy current loss based on RNA by taking into consideration the magnetic reaction field caused by the eddy current. First, an electric network model for calculating eddy current is described. Next, the RNA model is presented by taking into account the magnetic reaction field by using magnetic inductance is presented. The validity of the proposed model is proved by comparing it with the finite element method (FEM) and an experiment.
Experimental evaluation of characteristics of SR motor made of permendur Peer-reviewed

Yu Hasegawa, Kenji Nakamura, Osamu Ichinokura

IEEJ Transactions on Industry Applications　132　(4)　1-463　2012

DOI： 10.1541/ieejias.132.458 　

ISSN： 0913-6339 1348-8163
Basic Examination of Eddy Current loss Estimation in SPM Motor Based on Electric and Magnetic Networks

Y. Yoshida, K. Nakamura, O. Ichinokura

2012 XXTH INTERNATIONAL CONFERENCE ON ELECTRICAL MACHINES (ICEM)　1586-1591　2012

DOI： 10.1109/ICElMach.2012.6350090 　
A Design of Axial-gap Switched Reluctance Motor for In-Wheel Direct-Drive EV

Tohru Shibamoto, Kenji Nakamura, Hiroki Goto, Osamu Ichinokura

2012 XXTH INTERNATIONAL CONFERENCE ON ELECTRICAL MACHINES (ICEM)　1160-1165　2012

DOI： 10.1109/ICElMach.2012.6350022 　
Basic Consideration of Switched Reluctance Motor with Auxiliary Windings and Permanent Magnets

Y. Hasegawa, K. Nakamura, O. Ichinokura

2012 XXTH INTERNATIONAL CONFERENCE ON ELECTRICAL MACHINES (ICEM)　92-97　2012

DOI： 10.1109/ICElMach.2012.6349846 　
A Method for Optimizing the Design of SPM Type Magnetic Gear Based on Reluctance Network Analysis

M. Fukuoka, K. Nakamura, O. Ichinokura

2012 XXTH INTERNATIONAL CONFERENCE ON ELECTRICAL MACHINES (ICEM)　30-35　2012

DOI： 10.1109/ICElMach.2012.6349834 　
Super-Multipolar Permanent Magnet Reluctance Generator Designed for Small-Scale Renewable Energy Generation

K. Nakamura, O. Ichinokura

2012 XXTH INTERNATIONAL CONFERENCE ON ELECTRICAL MACHINES (ICEM)　489-494　2012

DOI： 10.1109/ICElMach.2012.6351842 　
A Consideration of Electric and Magnetic Networks for Calculating Eddy Current Loss in SPM Motor

Yukihiro Yoshida, Kenji Nakamura, Osamu Ichinokura

2012 15TH INTERNATIONAL CONFERENCE ON ELECTRICAL MACHINES AND SYSTEMS (ICEMS 2012)　LS3C-5　2012
Experimental tests of Surface Permanent Magnet Magnetic Gear

Michinari Fukuoka, Kenji Nakamura, Osamu Ichinokura

2012 15TH INTERNATIONAL CONFERENCE ON ELECTRICAL MACHINES AND SYSTEMS (ICEMS 2012)　LS4A-4　2012
Characteristics of Novel Flux Barrier Type Outer Rotor IPM Motor with Rare-earth and Ferrite Magnets

Soichi Ishii, Yu Hasegawa, Kenji Nakamura, Osamu Ichinokura

INTERNATIONAL CONFERENCE ON RENEWABLE ENERGY RESEARCH AND APPLICATIONS (ICRERA)　2012

DOI： 10.1109/ICRERA.2012.6477448 　

ISSN： 2377-6897
Basic Examination of Magnetic Circuit Model Incorporating Micromagnetic Simulation

Hideaki Tanaka, Kenji Nakamura, Osamu Ichinokura

INTERNATIONAL CONFERENCE ON RENEWABLE ENERGY RESEARCH AND APPLICATIONS (ICRERA)　2012

DOI： 10.1109/ICRERA.2012.6477450 　

ISSN： 2377-6897
Characteristics of Novel Flux Barrier Type Outer Rotor IPM Motor with Rare-earth and Ferrite Magnets Peer-reviewed

Soichi Ishii, Yu Hasegawa, Kenji Nakamura, Osamu Ichinokura

INTERNATIONAL CONFERENCE ON RENEWABLE ENERGY RESEARCH AND APPLICATIONS (ICRERA)　37　(3-2)　259-263　2012

DOI： 10.3379/msjmag.1305R004 　

ISSN： 2377-6897
Experimental tests of Surface Permanent Magnet Magnetic Gear Peer-reviewed

Michinari Fukuoka, Kenji Nakamura, Osamu Ichinokura

2012 15TH INTERNATIONAL CONFERENCE ON ELECTRICAL MACHINES AND SYSTEMS (ICEMS 2012)　3　(1)　62-67　2012

DOI： 10.1541/ieejjia.3.62 　
Dynamic Analysis of Planetary-Type Magnetic Gear Based on Reluctance Network Analysis Peer-reviewed

Michinari Fukuoka, Kenji Nakamura, Osamu Ichinokura

IEEE TRANSACTIONS ON MAGNETICS　47　(10)　2414-2417　2011/10

DOI： 10.1109/TMAG.2011.2157100 　

ISSN： 0018-9464
A Method for Calculating Eddy Current Loss Distribution Based on Reluctance Network Analysis Peer-reviewed

Yukihiro Yoshida, Kenji Nakamura, Osamu Ichinokura

IEEE TRANSACTIONS ON MAGNETICS　47　(10)　4155-4158　2011/10

DOI： 10.1109/TMAG.2011.2156397 　

ISSN： 0018-9464
Calculation of Characteristics of Three-phase Laminated-core Variable Inductor using MATLAB/Simulink Peer-reviewed

Y. Abe, H. Goto, K. Nakamura, T. Ohinata, K. Arimatsu, K. Sakamoto, O. Ichinokura

Journal of the Magnetics Society of Japan　35　(4)　394-398　2011/07
Publisher: The Magnetics Society of Japan
DOI： 10.3379/msjmag.1106R014 　

ISSN： 1882-2924

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Variable inductors, which consist of a magnetic core and primary dc and secondary ac winding, can control the effective inductance of the secondary ac winding with primary dc current. Hence, they can be applied to electric power systems to compensate for reactive power. We proposed a three-phase laminated-core variable inductor in a previous paper, and demonstrated that its weight was reduced by more than 30% as compared with the conventional one. However, simulation including a control system is required to apply a variable inductor as a reactive power compensator. We therefore propose a method of calculating the characteristics of a three-phase laminated-core variable inductor using MATLAB/Simulink, which is suitable for the designing and analyzing the control system. We also evaluated a method of controlling the variable inductor with an asymmetric half-bridge converter.
A Method for Calculating an Eddy Current for Reluctance Network Analysis Peer-reviewed

Y. Yoshida, K. Nakamura, O. Ichinokura

Journal of the Magnetics Society of Japan　35　(4)　399-403　2011/07
Publisher: The Magnetics Society of Japan
DOI： 10.3379/msjmag.1106R015 　

ISSN： 1882-2924

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In recent years, designing and analyzing of permanent magnet (PM) motors taking into consideration magnetic nonlinearity and eddy current loss in rare-earth magnets has increased in importance since the PM motors are driven by a three-phase PWM inverter and the working flux density is very high. In previous papers, we proposed a method for calculating the characteristics of PM motors based on reluctance network analysis (RNA). The proposed RNA model of the PM motors can be coupled with the inverter and mechanical system. Using the proposed model, we accurately calculated the iron loss in the stator core of the PM motor. However, the eddy current loss in the permanent magnets caused by carrier harmonics and slot harmonics was not discussed. We present here a method for calculating the eddy current loss based on an electric network that can be coupled with the RNA model. To verify the validity of the proposed method, the estimated values are compared with those obtained using a finite element method (FEM) and an experiment.
RNA Model of IPM Motor Using Variable Magnetomotive Forces and Variable Reluctances Peer-reviewed

K. Suzuki, K. Nakamura, O. Ichinokura

Journal of the Magnetics Society of Japan　35　(3)　281-284　2011/05
Publisher: The Magnetics Society of Japan
DOI： 10.3379/msjmag.10R032zG 　

ISSN： 1882-2924

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Interior permanent magnet (IPM) motors have large amounts of torque and are much more efficient than other motors since they can utilize both magnetic torque and reluctance torque together. However, the current vector needs to be controlled to utilize both torques effectively. Hence, it is necessary to design and analyze motor drive circuits in addition to motor structures. We propose a method of calculating the characteristics of an IPM motor based on reluctance network analysis (RNA). The proposed RNA model of the IPM motor consists of multiple nonlinear reluctances and magnetomotive forces, which periodically change with the rotor position so that the rotary motion of the rotor can be simulated. The RNA model can easily be coupled with an electric circuit and mechanical system. Therefore, it is suitable for designing and analyzing the IPM motor-drive system. The validity of the proposed method is proved by comparing its results with those obtained from the finite element method (FEM).
Basic Examination of Configuration of Axial-gap SR Motor Peer-reviewed

Y. Ono, K. Nakamura, O. Ichinokura

Journal of the Magnetics Society of Japan　35　(2)　106-111　2011/03
Publisher: The Magnetics Society of Japan
DOI： 10.3379/msjmag.10R038zG 　

ISSN： 1882-2924

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Switched reluctance (SR) motors have a doubly salient pole structure and concentrated individual winding on each stator pole, while the rotor has no winding or magnet. Hence, SR motors have several advantages such as a simple and robust structure, low manufacturing cost, and excellent reliability under high temperature. Such advantages make SR motors suitable for the in-wheel direct drive motors used in electric vehicles (EVs). However, higher torque density is required since the volume of the motors is limited by the wheel space. We designed three kinds of axial-gap SR motors, i.e., a single stator, a double stator, and three-stator, two-rotor motors. The basic characteristics of these motors were calculated with the finite element method (FEM). As a result, we demonstrated that the axial-gap SR motor had higher torque density than a conventional radial-gap SR motor.
Magnetic Circuit Analysis of a Permanent Magnet Motor Including Its Control System Peer-reviewed

Y. Kawano, K. Nakamura, O. Ichinokura

Journal of the Magnetics Society of Japan　35　(2)　112-117　2011/03
Publisher: The Magnetics Society of Japan
DOI： 10.3379/msjmag.10R039zG 　

ISSN： 1882-2924

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The recent importance of designing and analyzing permanent magnet (PM) motors taking into consideration magnetic nonlinearity, torque ripple due to slot harmonics, and the eddy current loss of rare-earth magnets is increasing following an increase in the power density of PM motors. In addition, both their drive circuits and controllers should be taken into account together since powerful and efficient motor drives are not achieved without current vector control. The finite element method (FEM) is widely used for designing and analyzing motors, but it is difficult to take current vector control into account. The magnetic circuit method has a simple analytical model and it is relatively accurate for calculations. Furthermore, electric-magnetic-mechanical coupled analysis can easily be carried out. We propose here a method of calculating a magnetic circuit for a PM motor with MATLAB/Simulink, and discuss a demonstration simulated using current vector control.
Development of a new two-dimensional position-sensitive detection based on resistive charge division and using CdTe detectors for a high-resolution semiconductor-based PET scanning

Ishii, K., Kikuchi, Y., Takahashi, K., Nakamura, K., Matsuyama, S., Terakawa, A., Yamazaki, H., Hitomi, K.

Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment　631　(1)　2011

DOI： 10.1016/j.nima.2010.11.115 　
18脚形三相一体構造可変インダクタの特性について

長尾真理子, 中村健二, 大日向敬, 有松健司, 坂本邦夫, 一ノ倉理

電気関係学会東北支部連合大会講演論文集　2011　33-33　2011
Publisher: 電気関係学会東北支部連合大会実行委員会
DOI： 10.11528/tsjc.2011.0_33 　
Sm-Fe-N ボンド磁石を用いたSPMモータの基礎特性

石井聡一, 中村健二, 一ノ倉理

電気関係学会東北支部連合大会講演論文集　2011　36-36　2011
Publisher: 電気関係学会東北支部連合大会実行委員会
DOI： 10.11528/tsjc.2011.0_36 　
極異方性ボンド磁石を用いた磁気ギアに関する一考察

福岡道成, 中村健二, 一ノ倉理

電気関係学会東北支部連合大会講演論文集　2011　35-35　2011
Publisher: 電気関係学会東北支部連合大会実行委員会
DOI： 10.11528/tsjc.2011.0_35 　
固定子ヨークに永久磁石と巻線を有するSRモータの特性

長谷川祐, 中村健二, 一ノ倉理

電気関係学会東北支部連合大会講演論文集　2011　44-44　2011
Publisher: 電気関係学会東北支部連合大会実行委員会
DOI： 10.11528/tsjc.2011.0_44 　
直流ヒステリシスを考慮した磁気回路モデルに関する一考察

藤田健太郎, 中村健二, 一ノ倉理

電気関係学会東北支部連合大会講演論文集　2011　34-34　2011
Publisher: 電気関係学会東北支部連合大会実行委員会
DOI： 10.11528/tsjc.2011.0_34 　
ダブルロータ型アキシャルギャップSRモータの基礎特性

柴本亨, 中村健二, 一ノ倉理

電気関係学会東北支部連合大会講演論文集　2011　45-45　2011
Publisher: 電気関係学会東北支部連合大会実行委員会
DOI： 10.11528/tsjc.2011.0_45 　
A Consideration of Eddy Current Loss Estimation Based on RNA

Tohoku-Section Joint Convention Record of Institutes of Electrical and Information Engineers, Japan　2011　17-17　2011
Publisher: Organizing Committee of Tohoku-Section Joint Convention of Institutes of Electrical and Information Engineers, Japan
DOI： 10.11528/tsjc.2011.0_17 　
Development of a Switched Reluctance Motor made of Permendur Peer-reviewed

Y. Hasegawa, K. Nakamura, O. Ichinokura

2ND INTERNATIONAL SYMPOSIUM ON ADVANCED MAGNETIC MATERIALS AND APPLICATIONS (ISAMMA 2010)　266　012067　2011

DOI： 10.1088/1742-6596/266/1/012067 　

ISSN： 1742-6588
A Method for Controlling Three-Phase-Laminated-Core Variable Inductor Applied to Reactive Power Compensator by Voltage Reversible Chopper

Yoshiaki Abe, Kenji Nakamura, Hiroki Goto, Takashi Ohinata, Kenji Arimatsu, Kunio Sakamoto, Osamu Ichinokura

PROCEEDINGS OF THE 2011-14TH EUROPEAN CONFERENCE ON POWER ELECTRONICS AND APPLICATIONS (EPE 2011)　481　2011

ISSN： 2325-0313
A Novel Switched Reluctance Machine with Windings and Permanent Magnets in the Stator Yoke

Yu Hasegawa, Kenji Nakamura, Osamu Ichinokura

PROCEEDINGS OF THE 2011-14TH EUROPEAN CONFERENCE ON POWER ELECTRONICS AND APPLICATIONS (EPE 2011)　482　2011

ISSN： 2325-0313
Dynamic Simulation of Planetary type Magnetic Gear based on Reluctance Network Analysis

Michinari Fukuoka, Kenji Nakamura, Osamu Ichinokura

PROCEEDINGS OF THE 2011-14TH EUROPEAN CONFERENCE ON POWER ELECTRONICS AND APPLICATIONS (EPE 2011)　505　2011

ISSN： 2325-0313
Basic Examination of Eddy Current Estimation based on Reluctance Network Analysis

Yukihiro Yoshida, Kenji Nakamura, Osamu Ichinokura

PROCEEDINGS OF THE 2011-14TH EUROPEAN CONFERENCE ON POWER ELECTRONICS AND APPLICATIONS (EPE 2011)　522　2011

ISSN： 2325-0313
Optimization of a Switched Reluctance Motor Made of Permendur Peer-reviewed

Yu Hasegawa, Kenji Nakamura, Osamu Ichinokura

IEEE TRANSACTIONS ON MAGNETICS　46　(6)　1311-1314　2010/06

DOI： 10.1109/TMAG.2010.2041903 　

ISSN： 0018-9464
Characteristics Calculation of Axial-Gap Motor with Skew Based on Three-dimensional Reluctance Network Analysis Peer-reviewed

Yuki Ono, Kenji Nakamura, Osamu Ichinokura

Journal of the Magnetics Society of Japan　34　(3)　362-366　2010/05
Publisher: The Magnetics Society of Japan
DOI： 10.3379/msjmag.1003R059 　

ISSN： 1882-2924

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Axial-gap motors have higher torque density than those with conventional radial gaps because they are able to reduce the thickness of the motor and increase the number of poles with a relatively smaller radius. Therefore, axial-gap motors are expected to be applied to various fields such as home electrical appliances and the in-wheel motors for electric vehicles. The establishment of an optimal method of design for axial-gap motors is required, but it generally takes a long time to calculate the characteristics of these motors since it is necessary to analyze the three-dimensional electromagnetic field. To overcome this problem, this paper presents a method of calculating the characteristics of axial-gap motors with skew based on reluctance network analysis (RNA). The validity of the proposed method is tested and proved by comparing the measurements with the results from finite element method (FEM) analysis.
Consideration of Rotor Structure in Permanent-Magnet Magnetic Gears Peer-reviewed

Tetsuya Ikeda, Kenji Nakamura, Osamu Ichinokura

Journal of the Magnetics Society of Japan　34　(3)　380-384　2010/05

DOI： 10.3379/msjmag.1003R057 　
Experimental verification of performance of a switched reluctance motor made of permendur

Y. Hasegawa, K. Nakamura, O. Ichinokura

19th International Conference on Electrical Machines, ICEM 2010　RF-002801　2010

DOI： 10.1109/ICELMACH.2010.5607918 　
Outer-Rotor type Permanent Magnet Reluctance Generator with High Power and Low Toque Ripple

Kenji Nakamura, Jun Yoshida, Osamu Ichinokura

IECON 2010 - 36TH ANNUAL CONFERENCE ON IEEE INDUSTRIAL ELECTRONICS SOCIETY　2242-2245　2010

DOI： 10.1109/IECON.2010.5674933 　

ISSN： 1553-572X
Stator-permanent-magnet reluctance generator using ferrite magnet for small-scale renewable energy generation Peer-reviewed

Kenji Nakamura, Jun Yoshida, Osamu Ichinokura

EPE Journal (European Power Electronics and Drives Journal)　20　(4)　31-36　2010
Publisher: EPE Association
DOI： 10.1080/09398368.2010.11463775 　

ISSN： 0939-8368
Iron Loss Calculation in a Three-Phase-Laminated-Core Variable Inductor Based on Reluctance Network Analysis Peer-reviewed

Kenji Nakamura, Shuhei Hisada, Kenji Arimatsu, Takashi Ohinata, Kunio Sakamoto, Osamu Ichinokura

IEEE TRANSACTIONS ON MAGNETICS　45　(10)　4781-4784　2009/10

DOI： 10.1109/TMAG.2009.2023247 　

ISSN： 0018-9464
Design and Development of a Three-Stacked 12/8 Permanent-Magnet-Type Reluctance Generator Peer-reviewed

Jun Yoshida, Kenji Nakamura, Osamu Ichinokura

Journal of the Magnetics Society of Japan　33　(3)　303-306　2009/05
Publisher: The Magnetics Society of Japan
DOI： 10.3379/msjmag.0903RG8011 　

ISSN： 1882-2924

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A permanent-magnet-type reluctance generator (PMRG) has a doubly salient pole structure. The permanent magnets are embedded in the stator yoke, and the concentrated windings are arranged individually around each stator pole. On the other hand, since the rotor has neither permanent magnets nor windings, the PMRG has a simple and robust structure, low cost, and high efficiency. Thus, it is suitable for wind-turbine generation and small-scale hydroelectric power generation. Although it has large torque ripple due to the salient pole structure, we have proposed a multi-stacked PMRG to reduce the torque ripple. This paper describes the design of a three-stacked 12/8 PMRG of 400 W by the finite element method (FEM). In addition, experimental results obtained with a trial generator are presented.
Analysis of Interior Permanent Magnet Synchronous Motors (IPMSMs) Using Reluctance Network Analysis (RNA) Peer-reviewed

Tatsuya Hasegawa, Hiroki Goto, Kenji Nakamura, Osamu Ichinokura

Journal of the Magnetics Society of Japan　33　(3)　311-314　2009/05
Publisher: The Magnetics Society of Japan
DOI： 10.3379/msjmag.0903RG8023 　

ISSN： 1882-2924

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Interior permanent magnet synchronous motors (IPMSMs) are highly efficient and have high torque density because they utilize magnetic torque and reluctance torque, which the driving method has an effect on. They have been used in various fields such as consumer electronics and electric vehicles in recent years and are expected to become increasingly popular. It is important to design IPMSMs optimally by taking control into consideration. This paper presents a method of calculating the characteristics of IPMSMs based on Reluctance Network Analysis (RNA). First, we constructed on RNA model of an IPMSM. Next, the RNA model was evaluated with its driving circuit and motion equation on "Simplorer". We successfully analysed an IPMSM.
Experimental Verification of a Three-Phase-Laminated-Core Variable Inductor Peer-reviewed

Shuhei Hisada, Kenji Nakamura, Kenji Arimatsu, Takashi Ohinata, Kunio Sakamoto, Osamu Ichinokura

Journal of the Magnetics Society of Japan　33　(2)　126-129　2009/03
Publisher: The Magnetics Society of Japan (MSJ)
DOI： 10.3379/msjmag.0901RG8001 　

ISSN： 1882-2924

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A variable inductor, which consists of only a magnetic core and primary dc and secondary ac windings, can regulate the secondary winding inductance continuously by dc excitation from the primary winding. The variable inductor is expected to be applied to reactive power compensation in electric power systems, because it has a simple and robust structure that is extremely reliable. In a previous paper, a three-phase-laminated-core variable inductor was proposed, which has three-phase secondary ac windings installed in one laminated core to reduce the size and weight in comparison with those of a single-phase variable inductor. This paper presents an experimental verification of the proposed three-phase-laminated-core variable inductor at various ac voltages. The copper and iron losses and the efficiency of the variable inductor are also shown.
A Way to Improve Efficiency of Permanent-Magnet Magnetic Gears Peer-reviewed

Tetsuya Ikeda, Kenji Nakamura, Osamu Ichinokura

Journal of the Magnetics Society of Japan　33　(2)　130-134　2009/03
Publisher: The Magnetics Society of Japan (MSJ)
DOI： 10.3379/msjmag.0901RG8016 　

ISSN： 1882-2924

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Magnetic gears have advantages such as having low acoustic noise and being maintenance-free in comparison with widely-used mechanical gears. This paper deals with a magnetic planetary gear which has inner and outer surface permanent-magnet rotors, and has ferromagnetic-stator pole pieces arranged between both rotors. The magnetic planetary gear has higher transmission torque than other types of magnetic gears since all rotor magnets continuously contribute to generating torque. However, it has not been put into practical use yet. To achieve future practical use, this paper describes a method of improving the efficiency of magnetic planetary gears.
Investigation into Characteristics of Switched Reluctance Motors Peer-reviewed

Yu Hasegawa, Kenji Nakamura, Osamu Ichinokura

Journal of the Magnetics Society of Japan　33　(2)　135-139　2009/03
Publisher: The Magnetics Society of Japan (MSJ)
DOI： 10.3379/msjmag.0901RG8017 　

ISSN： 1882-2924

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A switched reluctance (SR) motor has salient stator and rotor poles. Concentrated windings individually turn around all stator poles, while the rotor pole has no windings or magnets. Therefore, the SR motor has the following features: a simple and robust structure, large thermal resistance, faster rotation, and low-cost construction. To improve the output power and efficiency of rotating machines, investigations into various materials have recently been conducted to replace conventional non-oriented silicon steel such as grain-oriented silicon steel and soft magnetic composites (SMCs). This paper investigates the possibility of utilizing SR motors made of permendur. We estimated the torque-current characteristics, iron-loss characteristics, and the efficiency of an SR motor using the finite element method (FEM). Furthermore, a suitable structure for SR motors made of permendur is proposed.
Simulation of IPM motor with current vector control drive and DTC drive by nonlinear magnetic circuit model Peer-reviewed

Hiroki Goto, Kensuke Kimura, Kenji Nakamura, Osamu Ichinokura

ICEM: 2008 INTERNATIONAL CONFERENCE ON ELECTRICAL MACHINES, VOLS 1- 4　2158-2162　2009
A Novel High Power Permanent Magnet Reluctance Generator using Ferrite Magnet

Kenji Nakamura, Jun Yoshida, Osamu Ichinokura

EPE: 2009 13TH EUROPEAN CONFERENCE ON POWER ELECTRONICS AND APPLICATIONS, VOLS 1-9　697-704　2009
Feasibility Study of Switched Reluctance Motors Made of Permendur

Yu Hasegawa, Kenji Nakamura, Osamu Ichinokura

EPE: 2009 13TH EUROPEAN CONFERENCE ON POWER ELECTRONICS AND APPLICATIONS, VOLS 1-9　5198-5204　2009
A description of a design method of a claw teeth motor on the basis of three-dimensional reluctance network analysis Peer-reviewed

Takahiro Mizuguchi, Kenji Nakamura, Takayuki Koyama, Osamu Ichinokura

IEEJ Transactions on Industry Applications　129　(11)　5-1053　2009

DOI： 10.1541/ieejias.129.1048 　

ISSN： 0913-6339 1348-8163
Development of a Novel Three-Phase Laminated-Core Variable Inductor for Var Compensation Peer-reviewed

Kenji Nakamura, Shuhei Hisada, Kenji Arimatsu, Takashi Ohinata, Kunio Sakamoto, Osamu Ichinokura

IEEE TRANSACTIONS ON MAGNETICS　44　(11)　4107-4110　2008/11

DOI： 10.1109/TMAG.2008.2002861 　

ISSN： 0018-9464
Three-dimensional Reluctance Network Analysis of an EIE-Core Variable Inductor and Application to Reactive Power Compensation in a Distribution System Peer-reviewed

Kenji Nakamura, Takashi Ohinata, Kenji Arimatsu, Kunio Sakamoto, Osamu Ichinokura

IEEJ Transactions on Fundamentals and Materials　128　(8)　511-516　2008/08
Publisher: The Institute of Electrical Engineers of Japan
DOI： 10.1541/ieejfms.128.511 　

ISSN： 0385-4205

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This paper describes a three-dimensional reluctance network analysis (RNA) of an EIE-core variable inductor, which can be applied as a reactive power compensator in electric power systems. First, a three-dimensional RNA model of an EIE-core considering the magnetic saturation and iron loss is presented. Using the proposed RNA model with external electric circuits, operating characteristics of the variable inductor including the iron loss are calculated accurately. Next, high performance of a 6.6 kV-300 kVA reactive power compensator using the EIE-core variable inductor is demonstrated in a distribution system.
Reluctance Network Analysis of Wind Power Systems Using Permanent-Magnet Reluctance Generator Peer-reviewed

Osamu Ichinokura, Masayuki Kubota, Hiroki Goto, Kenji Nakamura

Journal of the Magnetics Society of Japan　32　(3)　392-395　2008/05
Publisher: The Magnetics Society of Japan (MSJ)
DOI： 10.3379/msjmag.32.392 　

ISSN： 1882-2924

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Wind power generators are well known as renewable sources of energy and permanent-magnetic reluctance generators are expected to be used for these. Although they can generally be simulated using the finite element method, this is not suitable for complex systems such as wind power generators. We simulated wind power generation using a permanent-magnetic reluctance generator with a DC micro grid system. The results revealed the possibility of implementing a wind power generation system.
Basic Characteristics of Three-phase Variable Inductor Peer-reviewed

Kenji Nakamura, Shuhei Hisada, Takashi Ohinata, Kenji Arimatsu, Yoshihiko Sato, Osamu Ichinokura

Journal of the Magnetics Society of Japan　32　(3)　415-418　2008/05
Publisher: The Magnetics Society of Japan (MSJ)
DOI： 10.3379/msjmag.32.415 　

ISSN： 1882-2924

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A variable inductor consists of magnetic cores and primary and secondary windings. It can regulate the effective inductance of the secondary winding by dc excitation from the primary winding. Variable inductors are expected to be applied to reactive power compensation in electric power systems, because they have a simple robust structure that is extremely reliable. This paper proposes a novel three-phase variable inductor to reduce size and weight. First, the operating principles of the proposed variable inductor are explained. Next, basic characteristics of the proposed variable inductor we calculated by reluctance network analysis (RNA) and the finite element method (FEM) are presented, which we compare with those of a conventional EIE-core variable inductor.
Calculation of the Dynamic Characteristics of a Magnetic Gear Based on Reluctance Network Analysis Peer-reviewed

Kenji Nakamura, Toshiaki Tashiro, Osamu Ichinokura

Journal of the Magnetics Society of Japan　32　(2-1)　78-81　2008/03
Publisher: The Magnetics Society of Japan (MSJ)
DOI： 10.3379/msjmag.32.78 　

ISSN： 1882-2924

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This paper presents a method for calculating the characteristics of a magnetic gear on the basis of reluctance network analysis (RNA). The magnetic gear has inner and outer permanent magnet rotors, and has ferromagnetic stator pole-pieces arranged between the two rotors. The inner and outer rotors rotate in opposite directions with a certain gear ratio determined by the number of pole-pairs of the rotors. This magnetic gear has a higher performance than others because all the rotor magnets always contribute to the transmission of torque. The steady-state characteristics of the magnetic gear are calculated by RNA, and are then compared to the results obtained by the finite element method (FEM). Finally, the dynamic behavior of the magnetic gear is simulated by RNA.
Consideration of Reduction in Eddy Current Loss in EIE-Core Variable Inductors Peer-reviewed

Kenji Nakamura, Takeshi Tomonaga, Shuhei Hisada, Kenji Arimatsu, Takashi Ohinata, Yoshihiko Sato, Osamu Ichinokura

Journal of the Magnetics Society of Japan　32　(2-1)　82-85　2008/03
Publisher: The Magnetics Society of Japan (MSJ)
DOI： 10.3379/msjmag.32.82 　

ISSN： 1882-2924

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EIE-core variable inductors have useful features in that they are easy to scale up because they are made from a laminated silicon steel sheet, and their output current is almost sinusoidal without an air gap or a low pass filter. Hence, practical applications of EIE-core variable inductors as voltage regulators in electric power systems are expected. A highly accurate numerical calculation based on reluctance network analysis (RNA) was introduced in previous papers. Various characteristics including eddy current loss on the laminated silicon steel can be estimated using RNA. This paper proposes a method of reducing eddy current loss in variable inductors. The cutting plane of the EIE-core due to the reduced eddy current loss is determined based on the flux distribution calculated by RNA. An over 10% reduction in iron loss is demonstrated to be possible based on the proposed method.
Reluctance network based dynamic analysis in power magnetics

Kenji Nakamura, Osamu Ichinokura

IEEJ Transactions on Fundamentals and Materials　128　(8)　506-510　2008
Publisher: IEEJ
DOI： 10.1541/ieejfms.128.506 　

ISSN： 0385-4205 1347-5533
Dynamic Simulation of PM Motor Drive System based on Reluctance Network Analysis

Kenji Nakamura, Osamu Ichnokura

2008 13TH INTERNATIONAL POWER ELECTRONICS AND MOTION CONTROL CONFERENCE, VOLS 1-5　758-762　2008

DOI： 10.1109/EPEPEMC.2008.4635358 　
Calculation of dynamic characteristics of electrical machinery based on reluctance network analysis

K. Nakamura, O. Ichinokura

APCOM'07-EPMESC XI　MS43-1-4　2007/12
A Consideration of Main-Winding Configuration for an EIE Core Variable Inductor Peer-reviewed

Kenji Nakamura, Takeshi Tomonaga, Kenji Arimatsu, Shigeaki Akatsuka, Takashi Ohinata, Yoshihiko Sato, Osamu Ichinokura

Journal of the Magnetics Society of Japan　31　(3)　241-245　2007/05
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.31.241 　

ISSN： 0285-0192

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An EIE core can be used as a variable inductor with a simple structure and good controllability. It is suitable for larger-capacity machines since it is with a laminated iron core. In addition, it has no gaps for harmonic current reduction. Therefore, it is expected that the EIE core variable inductor will be used as an automatic voltage regulator (AVR) for electric power systems. However, some aspects of the core operation have not been clarified. One of them is the main winding configuration. The EIE core has two main windings, which are wound around the top and bottom center-legs and connected so that the fluxes generated by the winding currents are in opposite directions. On the other hand, if the main windings are connected so that the fluxes are not in opposite directions, the control characteristic becomes worse, although the core structure remains the same. In this paper, the influence of the main winding configuration is investigated by using reluctance network analysis (RNA) and the finite element method (FEM).
A Novel Switched Reluctance Motor with Permanent Magnets between the Stator Poles Peer-reviewed

Kenji Nakamura, Kohei Murota, Osamu Ichinokura

Journal of the Magnetics Society of Japan　31　(2)　123-126　2007/03
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.31.123 　

ISSN： 0285-0192

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A switched reluctance (SR) motor has a doubly salient pole structure. It has some merits in comparison with other motors: simple structure, robustness, low cost, and capability for high-speed rotation. However, there are problems of torque ripple and acoustic noise. In addition, the power-to-weight ratio and efficiency need to be improved. Recent advances in power electronics technology allow meticulous current control to reduce the ripple and noise. On the other hand, the core material and motor structure must be further examined to improve the power-to-weight ratio and efficiency. This paper presents a novel SR motor with permanent magnets between the stator poles. The characteristics of the proposed motor are calculated by using a finite element method (FEM) and compared with those of conventional SR motors. The availability of the proposed SR motor is then clarified experimentally.
Dynamic Analysis of VR Stepping Motor based on Reluctance Network Peer-reviewed

Tomoaki Miyashita, Kenji Nakamura, Osamu Ichinokura

Journal of the Magnetics Society of Japan　31　(2)　127-130　2007/03
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.31.127 　

ISSN： 0285-0192

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Stepping motors are widely used in office automation (OA) and facility automation (FA) because they are simple and easy to control. However, it is difficult to calculate their dynamic characteristics because their rotational motion is discontinuous. This paper presents electromagnetic and motion coupled analysis of a variable reluctance (VR) stepping motor. First, a reluctance network analysis (RNA) model of the VR stepping motor is presented. Next, measured Coulomb and viscous friction of the motor are discussed to take the influence of friction in the coupled analysis into account. The RNA model is combined with the motor's drive circuit and motion-calculation circuits in SPICE. The dynamic characteristics of the VR stepping motor could be accurately calculated using the proposed coupled analysis model.
Characteristics of a novel switched reluctance motor having permanent magnets between the stator pole-tips

Kenji Nakamura, Kohei Murota, Osamu Ichinokura

2007 EUROPEAN CONFERENCE ON POWER ELECTRONICS AND APPLICATIONS, VOLS 1-10　1958-1962　2007

DOI： 10.1109/EPE.2007.4417298 　
A method for calculating iron loss of an SR motor based on reluctance network analysis and comparison of symmetric and asymmetric excitation Peer-reviewed

Kenji Nakamura, Shinya Fujio, Osamu Ichinokura

IEEE TRANSACTIONS ON MAGNETICS　42　(10)　3440-3442　2006/10

DOI： 10.1109/TMAG.2006.879079 　

ISSN： 0018-9464
Characteristics of 8/6 switched reluctance generator excited by suppression resistor converter Peer-reviewed

A. Takahashi, H. Goto, K. Nakamura, T. Watanabe, O. Ichinokura

IEEE TRANSACTIONS ON MAGNETICS　42　(10)　3458-3460　2006/10

DOI： 10.1109/TMAG.2006.880388 　

ISSN： 0018-9464
Reluctance Network Analysis of an SR motor Considering Iron loss characteristics and the Optimum Direction of Excitation

K. Nakamura, S. Fujio, O. Ichinokura

ICEM2006　PTA2-7　2006/09
Three-dimensional Reluctance Network Analysis of an EIE-Core Variable Inductor and Application to 300 kVA Automatic Voltage Regulator

K. Nakamura, T. Tomonaga, S. Akatsuka, T. Ohinata, Y. Sato, O. Ichinokura

ICEM2006　PTM3-20　2006/09
Reluctance Network Analysis Model of a Permanent Magnet Generator Considering an Overhang Structure and Iron loss

K. Nakamura, M. Ishihara, O. Ichinokura

ICEM2006　PSA1-16　2006/09
A Method for Dynamic Analysis of an Interior Permanent Magnet Motor Based on Nonlinear Magnetic Circuit

K. Nakamura, M. Ishihara, O. Ichinokura

ICEM2006　PSA1-2　2006/09
Calculation of Characteristics of an SR Motor with Divided Stator Core made of Grain-Oriented Silicon Steel

K. Murota, K. Nakamura, O. Ichinokura

ICEM2006　OTA2-2　2006/09
Multipolar Reluctance Generator Using Stator Core with Permanent Magnet

O. Ichinokura, T. Ono, T. Tashiro, A. Takahashi, K. Nakamura

ICEM2006　PSA1-17　2006/09
Three-Phase Reluctance Generator Using Stator Core with Permanent Magnet Peer-reviewed

Osamu Ichinokura, Tomoya Ono, Kenji Nakamura, Tadaaki Watanabe

Journal of the Magnetics Society of Japan　30　(3)　408-412　2006/05
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.30.408 　

ISSN： 0285-0192

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A switched reluctance generator (SRG) has desirable features including simple construction, high reliability, and low cost. Furthermore, it is suitable for use as an ultra-high-speed generator because its rotor is made of iron steel without any windings or permanent magnets. However, the SRG system is complicated, because it requires detection of the rotor position angle and excitation power for the excitation circuit of the stator winding. For this reason, it has not been used in practical applications. We previously proposed a new reluctance generator (RG) that has permanent magnets in the stator yoke. The experimental results obtained with a trial single-phase RG show that the proposed RG has very simple construction and high performance. However, the single-phase RG has the disadvantages of large leakage flux and cogging torque. In this paper, we evaluate a three-phase RG with permanent magnets buried in the stator core by simulation and experiments.
Design of outer-rotor-type multipolar switched reluctance motor for electric vehicle Peer-reviewed

S Fujishiro, K Ishikawa, S Kikuchi, K Nakamura, O Ichinokura

JOURNAL OF APPLIED PHYSICS　99　(8)　08R324　2006/04

DOI： 10.1063/1.2172180 　

ISSN： 0021-8979
A Method for Modeling the Eddy Current in an RNA Model of an EIE Core Peer-reviewed

Kenji Nakamura, Takeshi Tomonaga, Shigeaki Akatsuka, Takashi Ohinata, Kazuo Minazawa, Osamu Ichinokura

Journal of the Magnetics Society of Japan　30　(2)　273-276　2006/03
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.30.273 　

ISSN： 0285-0192

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Variable inductors can control the inductance of ac winding by dc excitation from a control circuit. For a large-capacity variable inductor, an EIE core is suitable because it is made of laminated iron and has no gaps for harmonic current reduction. EIE cores are expected to have practical applications to power control apparatuses in electric power systems. For optimum design of an EIE core, we previously proposed a reluctance network analysis (RNA). However, it is necessary to improve the accuracy of the iron loss calculation. This paper presents a method for modeling the eddy current caused by leakage flux in the laminated direction. We predict the paths of the eddy current, and express them in an electric circuit model. The eddy current circuit model is combined with the RNA model of an EIE core. We calculate the iron loss characteristics of the EIE core variable inductor, and evaluate the validity of the proposed method by comparing the calculated results with measured values.
Iron Loss Calculation Using a Reluctance Network Analysis Model of a Permanent Magnet Generator Peer-reviewed

Kenji Nakamura, Masahiro Ishihara, Osamu Ichinokura

Journal of the Magnetics Society of Japan　30　(2)　268-272　2006/03
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.30.268 　

ISSN： 0285-0192

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In a previous paper, we proposed a reluctance network analysis (RNA) model of a permanent magnet (PM) generator with a distributed winding and an overhang structure in which the permanent magnet is longer than the stator's stack in the axial direction. Using the RNA model, the basic characteristics of the PM generator were calculated accurately. A method for calculating the iron loss of the generator, however, was not discussed. In this paper, we estimate the iron loss on the basis of flux density waveforms calculated by using the RNA model. To verify the validity of the proposed method, the estimated values are compared with those given by a finite element method (FEM). In addition, we examine the accuracy of the flux and iron loss distribution obtained from the RNA model.
Operation Analysis for Electrical Machinery Based on Reluctance Network Peer-reviewed

Kenji Nakamura, Osamu Ichinokura

T. IEE Japan　126-A　(3)　150-156　2006/03
Publisher: The Institute of Electrical Engineers of Japan
DOI： 10.1541/ieejfms.126.150 　

ISSN： 0385-4205

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In this paper, we describe the basis of a magnetic circuit method and introduce a reluctance network analysis (RNA) proposed by authors. The RNA, which is based on the magnetic circuit method, has some suitable merits for simulating electrical machineries such as a simple analytical model, ease of coupled analysis with electrical circuits, motion, and thermal fields. In addition to these merits, a general-purpose circuit simulator like “SPICE" can be utilized as a solver. We present some applications of the RNA to operation analysis for an orthogonal-core, a switched reluctance motor, and a permanent magnet generator.
Electromechanical coupling factors of single-domain 0.67Pb (Mg <inf>1/3</inf> Nb <inf>2/3</inf> )O <inf>3</inf> -0.33 PbTiO <inf>3</inf> single-crystal thin films

Wasa, K., Ito, S., Nakamura, K., Matsunaga, T., Kanno, I., Suzuki, T., Okino, H., Yamamoto, T., Seo, S.H., Noh, D.Y.

Applied Physics Letters　88　(12)　2006

DOI： 10.1063/1.2188588
Calculation of characteristics of an SR motor with divided stator cores considering the influence of micro air gaps Peer-reviewed

K. Murota, K. Nakamura, O. Ichinokura

INTERMAG 2006 - IEEE International Magnetics Conference　772　2006

DOI： 10.1109/INTMAG.2006.376496 　
Reluctance Network Analysis Model of a Switched Reluctance Motor Taking Account of Iron Loss Peer-reviewed

Shinya Fujio, Kenji Nakamura, Osamu Ichinokura

Journal of the Magnetics Society of Japan　30　(1)　55-59　2006/01
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.30.55 　

ISSN： 0285-0192

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This paper presents a method for calculating the iron loss characteristics of a switched reluctance (SR) motor based on reluctance network analysis (RNA). The RNA model of the SR motor consists of a multiple number of nonlinear reluctances and magnetomotive forces (MMFs) exerted by a winding current. In addition to these elements, magnetic inductances that express the magnetic hysteresis are incorporated into the model. The RNA model of the SR motor is combined with its drive circuit and motion calculation circuits in SPICE, which is a general-purpose circuit simulator. Using the electromagnetic and motion-coupled models, we can calculate dynamic characteristics, including iron loss, quickly and accurately. We evaluate the validity of the proposed method by comparing the result with measured values.
A method for calculating iron loss of a switched reluctance motor based on reluctance network analysis

Kenji Nakamura, Shinya Fujio, Osamu Ichinokura

2006 12TH INTERNATIONAL POWER ELECTRONICS AND MOTION CONTROL CONFERENCE, VOLS 1-4　1491-+　2006

DOI： 10.1109/EPEPEMC.2006.283295 　
Characteristics of 8/6 SR generator with a suppression resistor converter

Atsushi Takahashi, Hiroki Goto, Kenji Nakamura, Tada-aki Watanabe, Osamu Ichinokura

2006 12TH INTERNATIONAL POWER ELECTRONICS AND MOTION CONTROL CONFERENCE, VOLS 1-4　1507-+　2006

DOI： 10.1109/EPEPEMC.2006.283298 　
Three-phase reluctance generator with permanent magnets buried in stator core

Osamu Ichinokura, Tomoya Ono, Atsushi Takahashi, Kenji Nakamura, Tadaaki Watanabe

2006 12TH INTERNATIONAL POWER ELECTRONICS AND MOTION CONTROL CONFERENCE, VOLS 1-4　1502-+　2006

DOI： 10.1109/EPEPEMC.2006.283297 　
A novel switched reluctance motor with wound-cores put on stator and rotor poles Peer-reviewed

K Nakamura, T Ono, H Goto, O Ichinokura

IEEE TRANSACTIONS ON MAGNETICS　41　(10)　3919-3921　2005/10

DOI： 10.1109/TMAG.2005.854965 　

ISSN： 0018-9464
Three-dimensional reluctance network analysis considering an iron loss characteristic for an EIE-core variable inductor Peer-reviewed

K Nakamura, S Hayakawa, S Akatsuka, T Ohinata, K Minazawa, O Ichinokura

IEEE TRANSACTIONS ON MAGNETICS　41　(10)　4033-4035　2005/10

DOI： 10.1109/TMAG.2005.854990 　

ISSN： 0018-9464
Development of a Variable Inductor for an Electric Power System

Osamu Ichinokura, Kenji Nakamura

Transactions of the Magnetics Society of Japan　5　(2)　49-56　2005/05/01
Publisher: The Magnetic Society of Japan
DOI： 10.3379/tmjpn2001.5.49 　

ISSN： 1346-7948

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This paper describes a variable inductor and its application to a power controller for use in an electric power system. First, we present an orthogonal-core-type variable inductor and a three-phase 6.6 kV-100 kVA reactive power compensator using orthogonal cores. In addition, applications to power apparatuses such as a series compensator and a phase shifter are described. Next, we introduce a novel EIE-core-type variable inductor designed for a larger capacity. The operating characteristics of a trial 6.6 kV-300 kVA reactive power compensator are presented. Finally, we present a method of calculating the operating characteristics of the variable inductors based on a method of three-dimensional nonlinear reluctance network analysis (RNA) proposed by the authors.
Basic Characteristics of a Reluctance Generator with Permanent Magnets Burried in the Stator Yoke Peer-reviewed

Osamu Ichinokura, Jun Shida, Kenji Nakamura, Tadaaki Watanabe

Journal of the Magnetics Society of Japan　29　(5)　571-576　2005/05
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.29.571 　

ISSN： 0285-0192

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A reluctance generator (RG) has various desirable features, including simple construction, high reliability, and low cost. Furthermore, it is suitable for an ultra-high-speed generator because the rotor of the RG is made of iron steel. However, the RG system is complicated, because it needs to detect the rotor position angle and requires a dc power supply for the driving circuit of the stator winding. For this reason, the RG has not been used in practical applications. In this paper, we propose a new RG with a permanent magnet in the stator yoke. The linkage flux of the stator winding from the permanent magnet changes with the salient-pole rotor. The experimental results obtained with a trial RG indicate that it has a very simple construction and high performance.
Calculation of the Characteristics of an Outer-Rotor-Type Multipolar SR Motor for Application to Electric Vehicles Peer-reviewed

Kenji Nakamura, Yosuke Suzuki, Hiroki Goto, Osamu Ichinokura

Transactions of the Magnetics Society of Japan　5　(2)　113-116　2005/05
Publisher: The Magnetics Society of Japan
DOI： 10.3379/tmjpn2001.5.113 　

ISSN： 1346-7948

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In this paper, we design and analyze an outer-rotor-type multipolar switched reluctance (SR) motor, and examine the possibility of realizing an electric vehicle (EV) with an SR motor inside each of its two rear wheels, that is, an EV with a gear-less and in-wheel layout. We used a method for calculating the operating characteristics proposedpreviously by authors for designing the SR motor, andevaluated the optimum exciting phase. Furthermore, we improved the proposed method so that the basiccharacteristics of the EV with SR motors can be calculated, and we investigated the initial and steady-state currents and the maximum speed of the vehicle.
Electromagnetic and motion-coupled analysis for switched reluctance motor based on reluctance network analysis Peer-reviewed

K Nakamura, K Kimura, O Ichinokura

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　290　1309-1312　2005/04

DOI： 10.1016/j.jmmm.2004.11.425 　

ISSN： 0304-8853
A new nonlinear magnetic circuit model for dynamic analysis of interior permanent magnet synchronous motor Peer-reviewed

K Nakamura, K Saito, T Watanabe, O Ichinokura

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　290　1313-1317　2005/04

DOI： 10.1016/j.jmmm.2004.11.426 　

ISSN： 0304-8853
Design of outer-rotor type multipolar SR motor for electric vehicle Peer-reviewed

K Nakamura, Y Suzuki, H Goto, O Ichinokura

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　290　1334-1337　2005/04

DOI： 10.1016/j.jmmm.2004.11.431 　

ISSN： 0304-8853
A multipolar SR motor and its application in EV Peer-reviewed

H Goto, Y Suzuki, K Nakamura, T Watanabe, HJ Guo, O Ichinokura

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　290　1338-1342　2005/04

DOI： 10.1016/j.jmmm.2004.11.432 　

ISSN： 0304-8853
Consideration of Optimal Construction of EIE-Core Peer-reviewed

Shuichi Hayakawa, Kenji Nakamura, Shigeaki Akatsuka, Mineo Kawakami, Takashi Ohinata, Kazuo Minazawa, Osamu Ichinokura

Journal of the Magnetics Society of Japan　29　(4)　494-497　2005/04
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.29.494 　

ISSN： 0285-0192

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Since an EIE-core variable inductor is constructed from cores and windings, it has desirable features for an electric power apparatus, such as simple construction and high reliability. The variable inductor does not need any gaps for harmonic current reduction and has a suitable structure for a larger capacity. It is expected that the EIE-core variable inductor is applied as an automatic voltage regulator to an electric power system. It is important to clarify the optimal construction of the EIE-core. In this paper, we compare basic characteristics of several EIE-cores which have different shape and size using reluctance network analysis (RNA) suggested by the authors. RNA is the improved calculation method based on magnetic circuit analysis.
Calculation of the Characteristics of a Permanent Magnet Generator Using Reluctance Network Peer-reviewed

Kenji Nakamura, Hu Li, Osamu Ichinokura

Journal of the Magnetics Society of Japan　29　(2)　165-169　2005/02
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.29.165 　

ISSN： 0285-0192

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This paper presents a method for calculating the operating characteristics of permanent magnet (PM) generators based on the reluctance network analysis (RNA) method proposed by the authors. The PM generator used in the discussion has a distributed winding and an overhang structure in which the permanent magnet is longer than the stator's stack in the axial direction. In the analysis, the stator and rotor, gap, and the permanent magnet including the overhang are expressed as a simplified three-dimensional RNA model. The RNA model of the PM generator is combined with an external electric circuit and motion calculation blocks on a general-purpose circuit simulator called "SPICE." We can readily calculate the characteristics of the PM generator using the combined model, including its transient state. The calculated values agree well with the measured ones.
Dynamic Operation Analysis of Electromagnetic Machine Based on Reluctance Network Analysis

Kenji Nakamura, Osamu Ichinokura

Journal of the Magnetic Society of Japan　28　(11)　1089-1095　2004/11/01
Publisher: The Magnetic Society of Japan
ISSN： 0285-0192

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The importance of high-precision analysis in design of electromagnetic machines, such as transformers, motors, and generators, is increasing day by day because of reductions in cycle time and cost for product development. Advantages of the magnetic circuit method include simplify of the analytical model and ease of calculation. This paper describes the basis of the magnetic circuit method and introduces Reluc tance Network Analysis (RNA) as proposed by the authors. RNA, based on the magnetic circuit method, was developed for high-precision analyses of the dynamic characteristics of electromagnetic machines. Applications of RNA to analysis of an orthogonal-core variable inductor, SR motor, and IPM motor are presented in this paper.
Electromagnetic and Motion Coupled Analysis for Switched Reluctance Motor Using a Nonlinear Magnetic Circuit Model

K. Nakamura, K. Kimura, O. Ichinokura

EPE-PEMC2004　A52267　2004/09
Design and Analysis of an Outer-Rotor Type Multipolar SR Motor for Application to the EV

Y. Suzuki, K. Nakamura, O. Ichinokura

EPE-PEMC2004　A52270　2004/09
Electromagnetic and thermal coupled analysis of ferrite orthogonal-core based on three-dimensional reluctance and thermal-resistance network model Peer-reviewed

K Nakamura, H Yoshida, O Ichinokura

IEEE TRANSACTIONS ON MAGNETICS　40　(4)　2050-2052　2004/07

DOI： 10.1109/TMAG.2004.832497 　

ISSN： 0018-9464
Simple Magnetic Circuit Model of Switched Reluctance Motor Considering Magnetic Saturation Peer-reviewed

Kenji Nakamura, Koshiro Kimura, Osamu Ichinokura

Journal of the Magnetics Society of Japan　28　(4)　602-606　2004/04
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.28.602 　

ISSN： 0285-0192

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A switched reluctance motor (SRM) has such desirable features as simple construction, high reliability, and low cost. The SRM has not, however, been put into wide application because of large torque ripple and acoustic noise. In addition, quantitative analysis and optimum design of the SRM have not been fully charified. In a previous paper, we proposed a simple magnetic circuit model of an SRM based on its configuration. We calculated such dynamic characteristics of the SRM as excitation voltage, winding current, and flux in each part of the motor. In this model, however, reluctance of the stator and rotor cores are approximated by a linear function. In order to improve the calculation accuracy, we have to consider nonlinear characteristics of the core material. Furthermore, local saturation occurring at stator and rotor pole-tips and leakage fluxes from the stator pole must be considered. In this paper, we examine a nonlinear magnetic circuit model of the SRM considering the local saturation at the pole-tips and the leakage fluxes.
Method for Expressing Magnetic Hysteresis in the Nonlinear Reluctance for SPICE Peer-reviewed

Koshiro Kimura, Kenji Nakamura, Osamu Ichinokura

Journal of the Magnetics Society of Japan　28　(4)　611-614　2004/04
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.28.611 　

ISSN： 0285-0192

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Magnetic circuit methods make it possible to analyze characteristics of various magnetic devices by simple calculations. Furthermore, we can use general-purpose tools, such as a SPICE circuit simulator, for calculation. In a previous paper, we proposed a method for calculating iron loss characteristics based on a magnetic circuit model considering iron loss. However, since this method treats hysteresis loss and eddy-current loss collectively, it is necessary to vary the parameters of the magnetic circuit model when frequency is varied. In this paper, we propose a method for calculating iron loss for each frequency without varying the parameters of the magnetic circuit.
Dynamic Analysis of Interior Permanent Magnet Synchronous Motor Based on Magnetic Circuit Method Peer-reviewed

Kenichi Saito, Kenji Nakamura, Osamu Ichinokura

Journal of the Magnetics Society of Japan　28　(4)　615-619　2004/04
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.28.615 　

ISSN： 0285-0192

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An interior permanent magnet synchronous motor (IPMSM) has high efficiency and torque because the motor utilizes both magnetic torque and reluctance torque, because of the locations of permanent magnets in the rotor. The IPMSM has many applications, such as in electrical household appliances, in office automations and in electrical vehicles. Establishment of the optimum design for an IPMSM is thus important. Here, we present one calculation method for the dynamic characteristics of an IPMSM with concentrated winding based on the magnetic circuit model. In this model, the magnetic circuit of the IPMSM is expressed by variable reluctance and permanent magnet magnetomotive forces (MMFs) changing with rotor angle. In order to obtain the reluctances and permanent magnet MMFs, we calculate fluxes passing through a stator pole using the finite element method (FFM). Using the proposed model, we can easily calculate dynamic characteristics of the IPMSM.
Excitation Methods for SRM Based on Electric- and Magnetic-Coupled Analysis Peer-reviewed

Hiroki Goto, Jun Shida, Kenji Nakamura, Hai Jiao Guo, Osamu Ichinokura

Journal of the Magnetics Society of Japan　28　(4)　627-631　2004/04
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.28.627 　

ISSN： 0285-0192

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Switched reluctance motors (SRMs) have such desirable features as simple construction, high reliability, and low cost. Characteristics of the SRM differ with the excitation timing or period even if the SRM is operated at the same source voltage, because motor torque depends on gap reluctance, which changes timing of SRMs have been reported in many papers. On the other hand, no examination of excitation direction has been reported. Furthermore, combinations of excitation direction in each phase also have not been investigated. In this paper, based on a finite element analysis, we examine the effects of an excitation direction on characteristics of the SRM.
Analysis of Operating Characteristics of EIE-Core Variable Inductor Based on Three-Dimensional Magnetic Circuit Peer-reviewed

Shuichi Hayakawa, Kenji Nakamura, Shigeaki Akatsuka, Tomoyuki Aoki, Mineo Kawakami, Takashi Ohinata, Kazuo Minazawa, Osamu Ichinokura

Journal of the Magnetic Society of Japan　28　(3)　425-428　2004/03
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.28.425 　

ISSN： 0285-0192

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Since an EIE-core variable inductor is constructed from cores and windings, it has good features for an electric power apparatus, such as simple construction and high reliability. The variable inductor does not need any gaps for harmonic current reduction and has a suitable structure for a larger capacity. For optimum design, a quantitative analysis method for the variable inductor is important. In a previous paper, we derived a two-dimensional nonlinear magnetic circuit model of the EIE-core and found operating characteristics of the variable inductor. Although the calculation value and actual measurement showed good coincidence, in the large domain of the control current, a tendency was shown to expand quantitive error, and further improvement in calculation accuracy became a subject. In this paper, we present a three-dimensional magnetic circuit to improve analysis accuracy, and compared calculated results with actual measurements.
Analysis of Operating Characteristics of Ferrite Orthogonal-Core Type Variable Inductor Based on Three-Dimensional Nonlinear Magnetic Circuit Considering the Iron Loss Peer-reviewed

Hirokazu Yoshida, Kenji Nakamura, Osamu Ichinokura

IEEJ Transactions on Industry Applications　123　(4)　386-391　2003/09/01

DOI： 10.1541/ieejias.123.386 　

ISSN： 1348-8163 0913-6339
Dynamic analysis of interior permanent magnet motor based on a magnetic circuit model Peer-reviewed

K Nakamura, K Saito, O Ichinokura

IEEE TRANSACTIONS ON MAGNETICS　39　(5)　3250-3252　2003/09

DOI： 10.1109/TMAG.2003.816738 　

ISSN： 0018-9464
Dynamic simulation model of switched reluctance generator Peer-reviewed

O Ichinokura, T Kikuchi, K Nakamura, T Watanabe, HJ Guo

IEEE TRANSACTIONS ON MAGNETICS　39　(5)　3253-3255　2003/09

DOI： 10.1109/TMAG.2003.816739 　

ISSN： 0018-9464
Calculation of Characteristics of Ferrite Pot-Core Noncontact Transformer by RNA Peer-reviewed

Minoru Ito, Kenji Nakamura, Osamu Ichinokura

Journal of the Magnetic Society of Japan　27　(4)　566-569　2003/04
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.27.566 　

ISSN： 0285-0192

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Analyses of a circuit constructed using magnetic and power electronic devices need to take into consideration nonlinear characteristics of the devices. Previous analysis and design methods for this circuit however, seem inadequate. In this paper, magnetization characteristics of a shared magnetic system are calculated using the reluctance network analysis (RNA) method. We manufactured a dc-dc converter, using pot cores as a noncontact electric power transmission unit, and examined many characteristics.
Consideration of Iron Loss and Temperature Analysis of Ferrite Orthogonal Core Peer-reviewed

Hirokazu Yoshida, Kenji Nakamura, Osamu Ichinokura

Journal of the Magnetic Society of Japan　27　(4)　561-565　2003/04
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.27.561 　

ISSN： 0285-0192

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An orthogonal core is a magnetic device which can continuously control the inductance of the secondary winding with the primary dc current. Recently orthogonal core variable inductors have been used in the high-frequency region. Analysis of this device for high-frequency applications is therefore necessary. We previously proposed an analysis method based on reluctance network analysis (RNA) for the silicon steel orthogonal core used in the commercial frequency region. In order to use the orthogonal core in a high-frequency region, we must consider the increase in the core temperature due to iron loss. In this paper, we calculate the iron loss of a ferrite orthogonal core variable inductor in the high-frequency region, based on RNA, and we estimate the core temperature on the basis of the thermal equivalent circuit.
Magneitc Circuit Model of a Distributed-Winding Brushless DC Motor for Use in SPICE Peer-reviewed

Satoshi Matsushita, Hiroki Nagao, Kenji Nakamura, Osamu Ichinokura

Journal of the Magnetic Society of Japan　27　(4)　538-542　2003/04
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.27.538 　

ISSN： 0285-0192

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This paper presents a method for calculation of the dynamic characteristics of a brushless dc motor (BLDCM) with a distributed winding. The calculation method is based on reluctance network analysis (RNA). In the analysis, the stator, rotor, and gap are expressed as a reluctance network circuit and controlled voltage sources for the magnetomotive force of the permanent, magnets of the rotor. By combining a driving inverter circuit and controlled system with a reluctance network circuit, we can readily calculate the dynamic characteristics of the BLDCM, including the distribution of flux density inside the BLDCM. The calculated results agree well with the experimental data. The calculation method proposed here is useful for optimum design of BLDCMs.
SPICE simulation of SRM considering nonlinear magnetization characteristics

T Tsukii, K Nakamura, O Ichinokura

ELECTRICAL ENGINEERING IN JAPAN　142　(1)　50-56　2003/01

DOI： 10.1002/eej.10092 　

ISSN： 0424-7760
Electric and magnetic simultaneous transient analysis method of switched reluctance motor for use on SPICE

K Nakamura, K Kimura, O Ichinokura

PEDS 2003 : FIFTH INTERNATIONAL CONFERENCE ON POWER ELECTRONICS AND DRIVE SYSTEMS, VOLS 1 AND 2, PROCEEDINGS　1614-1618　2003

DOI： 10.1109/PEDS.2003.1283232 　
SPICE Simulation of a SRM Considering the Nonlinear Magnetization Characteristics Peer-reviewed

Tomoyuki Tsukii, Kenji Nakamura, Osamu Ichinokura

IEEJ Transactions on Industry Applications　122　(1)　16-21　2002/09/01

DOI： 10.1541/ieejias.122.16 　

ISSN： 1348-8163 0913-6339
Calculation of Characteristics of Magnetic-Flux-Controlo Transformer Peer-reviewed

K. Nakamura, S. Akatsuka, T. Ohinata, T. Aoki, M. Maeda, H. Sato, O. Ichinokura

Journal of the Magnetics Society of Japan　26　(4)　572-575　2002/04
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.26.572 　

ISSN： 0285-0192

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We previously proposed a Magnetic-Flux-Control transformer (MFC transformer). The MFC transformer has simple construction and high reliability because it consists of only a core and its windings. The MFC transformer can control output voltage and net inductance easily and continuously. For wide application and practical use, it is necessary to establish a design method for the MFC transformer. In this paper, we present an analytical method for the MFC transformer using Reluctance Network Analysis (RNA) and examine the characteristics of an MFC transformer.
Analysis of Orthogonal Core SVC Using EMTP Peer-reviewed

S. Fujita, K. Nakamura, M. Maeda, H. Sato, O. Ichinokura

Journal of the Magnetics Society of Japan　26　(4)　576-579　2002/04
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.26.576 　

ISSN： 0285-0192

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We proposed a three-phase variable inductor for control equipment in an electric power system. The three-phase variable inductor is constructed with three orthogonal cores that have wedge gaps for reduction of harmonics. When the three-phase variable inductor is connected to a power line in parallel, a simple and reliable var compensator results. A trial three-phase, 100-kVA variable inductor was demonstrated in a 6.6-kV ac distribution system. In order to expand the application of the variable inductor, it is necessary to clear the operation of the variable inductor under various conditions in the electric power system. It is generally difficult, however in general to carry out field tests on an actual electric power system. Numerical simulation is an effective method for analysis of an electric power system. In particular, EMTP is one of the most widely used programs in the analysis of electric power systems. In this paper, we present an EMTP model of the orthogonal core variable inductor and apply the model to the analysis of an orthogonal core SVC.
Dynamic Analysis of Brushless DC Motor Based on Magnetic Circuit Model Peer-reviewed

G. Kimura, H. Nagao, K. Nakamura, O. Ichinokura

Journal of the Magnetics Society of Japan　26　(4)　633-636　2002/04
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.26.633 　

ISSN： 0285-0192

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In this paper, we propose a new analytical model for brushless dc motors that is based on the magnetic circuit. The magnetic circuit is constructed with magnetic reluctances of stator and rotor cores and magnetomotive force of the stator winding currents and permanent magnets. Combining the magnetic circuit, electrical circuit, electronic circuit, and control circuit, we can accurately analyze the dynamic characteristics of the brushless dc motor.
Analysis of No-load Charactristics of Linear Parametric Motor Based on RNA Method Peer-reviewed

Y. Yamanaka, S. Kikuchi, T. Watanabe, K. Nakamura, O. Ichinokura

Journal of the Magnetics Society of Japan　26　(4)　665-668　2002/04
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.26.665 　

ISSN： 0285-0192

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This paper describes the results of analyzing the operation of a linear parametric motor by using the SPICE simulator. We designed a model in which the common magnetic circuit is divided into three parts in the magnetic circuit of this motor. We also designed a magnetic circuit model in which the common magnetic circuit was divided into nine parts. In addition, to improve the calculation accuracy, a model was designed based on the RNA (Reluctance Network Analysis) method shown by a magnetic reluctance network.
Operating Characteristics of Orthogonal Core Phase Shifter Peer-reviewed

K. Nakamura, S. Akatsuka, T. Ohinata, M. Kawakami, M. Maeda, H. Sato, O. Ichinokura

Journal of the Magnetics Society of Japan　26　(3)　143-146　2002/03
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.26.143 　

ISSN： 0285-0192

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Rising demand for electric power has heightened the need for flow control in existing power systems. An orthogonal core has merit for a power controller, including simple construction and high reliability, because it consists of only a pair of cores and their windings. The orthogonal core can control net inductance of secondary windings easily and continuously. This paper presents an orthogonal core phase shifter for flow control in an electric power system. The phase shifter is constructed with the variable inductors and transformers. For reduction of harmonic currents, the orthogonal core utilizes wedge gaps and tertiary windings. In this paper, we examine the fundamental characteristics of the orthogonal core phase shifter.
Analysis of Operating Characteristics of Parallel-Laminated Core Type Variable Inductor Peer-reviewed

Kenji Nakamura, Shigeaki Akatsuka, Takashi Ohinata, Mineo Kawakami, Mitsuru Maeda, Hiromichi Sato, Osamu Ichinokura

T. IEE Japan　122-B　(2)　295-300　2002/02
Application of orthogonal-core transformer to series compensation for power system Peer-reviewed

K Nakamura, M Kawakami, M Maeda, H Sato, O Ichinokura

IEEE TRANSACTIONS ON MAGNETICS　37　(4)　2858-2861　2001/07

DOI： 10.1109/20.951328 　

ISSN： 0018-9464
Fundamental Operation of an Orthogonal-Core-Type Variable Inductor with a Third Winding Peer-reviewed

K. Nakamura, M. Kawakami, M. Maeda, H. Sato, O. Ichinokura

Journal of the Magnetics Society of Japan　25　(4-2)　999-1002　2001/04
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.25.999 　

ISSN： 0285-0192

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We previously proposed a three-phase variable inductor for control equipment in an electric power system. The three-phase variable inductor is constructed with three orthogonal cores that have wedge gaps for reduction of harmonics. When the three-phase variable inductor is connected to a power line in parallel, a simple, reliable var compensator will be realized. In order to reduce the 3rd harmonic of the output currents of the three-phase variable inductor, the secondary windings of the orthogonal cores are connected in a delta configuration. On the other hand, when the three-phase variable inductor is connected to the line in series, the variable inductor can control a power flow in a power system. However, the secondary windings cannot be connected in a delta configuration. In this paper, we present one method of reducing the 3rd harmonic by using the third windings of the orthogonal cores.
Shape Effect of Wedge Gaps in an Orthogonal-Core-Type Variable Inductor Peer-reviewed

K. Nakamura, M. Kawakami, M. Maeda, H. Sato, O. Ichinokura

Journal of the Magnetics Socirty of Japan　25　(4-2)　1003-1006　2001/04
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.25.1003 　

ISSN： 0285-0192

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By using an orthogonal-core-type variable inductor and capacitor, we will realize a simple, reliable, and high-quality voltage regulator. However, the nonlinear magnetization characteristic of the orthogonal core causes harmonics in the output current. To reduce the harmonic current of the orthogonal-core-type variable inductor, we previously proposed an orthogonal core with wedge gaps. A trial three-phase 100-kVA variable inductor demonstrates that the variable inductor can be put to practical use in a 6.6-kV ac distribution system. For wide application, it is necessary to examine the optimum size of the wedge gap and to establish a design method for the orthogonal core. In this paper, we present a method for quantitative analysis of the orthogonal core with wedge gaps, and examine the characteristics of the variable inductor for various dimensions of the wedge gap.
Development of a Magnetic-Flux-Control-Type Variable Inductor Peer-reviewed

S. Akatsuka, T. Ohinata, M. Kawakami, M. Maeda, H. Sato, K. Nakamura, O. Ichinokura

Journal of the Magnetics Society of Japan　25　(4-2)　1023-1026　2001/04
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.25.1023 　

ISSN： 0285-0192

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In a previous paper, we proposed a 3-phase variable inductor, which has a sinusoidal output current and good controllability. We developed a var compensator for a 6.6 kV ac distribution system using the 3-phase variable inductor, which is composed of three orthogonalcores that have wedge gaps for reducing the harmonics in the output current. To reduce the eddy current loss, the orthogonalcore needs a proper insulation film between the primary and the secondary core. When an apparatus is scaled up,
SPICE Model of Nonlinear Reluctance for Analysis of a Switched Reluctance Motor Peer-reviewed

T. Tsukii, K. Nakamura, O. Ichinokura

Journal of the Magnetics Society of Japan　25　(4-2)　1227-1230　2001/04
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.25.1227 　

ISSN： 0285-0192

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In a previous paper, the authors proposed a method for calculating the operating characteristics of a switched reluctance motor (SRM) on the basis of the general-purpose circuit simulation program "SPICE." The method was verified by experimental testing of a 4-phase 8/6 SRM. In the analysis, however, we neglected the effects of magnetic saturation. In this paper, we propose a SPICE model of the nonlinear reluctance of the SRM for analysis that takes into account of the magnetic saturation characteristics. The proposed model is verified by comparing the calculated magnetization curves obtained by using the model with those obtained by finite element analysis.
Analysis of orthogonal-core type linear variable inductor and application to VAR compensator Peer-reviewed

K Nakamura, O Ichinokura, M Maeda, S Akatsuka, K Takasugi, H Sato

IEEE TRANSACTIONS ON MAGNETICS　36　(5)　3565-3567　2000/09

DOI： 10.1109/20.908899 　

ISSN： 0018-9464
Connection Methods for Primary Windings of an Orthogonal-Core with Wedge Gap AVR Peer-reviewed

Kenji Nakamura, Mineo Kawakami, Shigeaki Akatsuka, Mitsuru Maeda, Hiromichi Sato, Osamu Ichinokura

Journal of the Magnetic Society of Japan　24　(4-2)　803-806　2000/04
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.24.803 　

ISSN： 0285-0192

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We explored connection of the primary windings of an orthogonal-core type three-phase variable inductor. The variable inductor can be applied to a var compensator for voltage regulation of the distribution system. In order to reduce third harmonic current in the output current, we connected the secondary windings of the orthogonal-cores in a delta configuration. The primary windings for dc control are connected in parallel because the harmonic distortion of the output currents increases when the primary windings are connected in series. The reason of the harmonic distortion had not been clarified, however. In this paper, we present the solution to the cause of harmonic distortion.
Calculation of the Characteristics of an Orthogonal-Core Type Variable Inductor with a Wedge Gap Peer-reviewed

Kenji Nakamura, Katsubumi Tajima, Mineo Kawakami, Mitsuru Maeda, Takayuki Ito, Osamu Ichinokura

Journal of the Magnetic Society of Japan　23　(4-2)　1497-1500　1999/04
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.23.1497 　

ISSN： 0285-0192

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By using an orthogonal-core-type variable inductor and capacitor, we will realize a simple, reliable, and high-quality voltage regulator. However, the nonlinear magnetization characteristic of the orthogonal core causes harmonics in the output current. Last year, in order to reduce the harmonic current of the variable inductor, we proposed an orthogonal core with wedge gaps. A trial three-phase 100 kVA variable inductor demonstrates that the variable inductor can be put to practical use in a 6.6-kV ac distribution system. For wide Appl.ication, it is necessary to establish a design method for the orthogonal core. This paper presents a method of calculating the characteristics an orthogonal core with wedge gaps.

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Misc. 187

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Enhancing Torque-to-Weight Ratio and Minimizing Permanent Magnet Usage in Large-Scale Magnetic Gears for Wind Power Generation

角貴則, 岡崎晃洋, 中村健二, 進士智一, 武田啓司

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Basic Examination of Reduction of Eddy Current Loss in Magnets of Flux-Modulated-type Magnetic Gears

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Torque Characteristics of Multipole Transverse-Flux-type SR motors

永井歩美, 永井歩美, 中村健二

電気学会研究会資料(Web)　(MAG-24-022-036)　2024
Electric-mechanical Conversion Technology Contributing to Carbon Neutrality-Higher Power and Efficiency Magnetic Gears and Magnetic Geared Motors-

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電気学会全国大会講演論文集(CD-ROM)　2023　2023
Reluctance Torque Improvement of Distributed-Winding Interior Permanent Magnet Motor

田村一樹, 中村健二, 成瀬賢哉, 萱野雅浩

電気学会研究会資料(Web)　(MAG-23-021-030)　2023
Development of High Power Density Motors for Electric Axles using Nd-Based Bonded Magnets

成瀬賢哉, KIM Choongsik, 萱野雅浩, 度會亜起, 御手洗浩成, 中村健二

電気学会研究会資料(Web)　(MD-23-118-137/RM-23-093-112)　2023
Basic Examination on Reluctance Network Model for V-Type IPM Motor

羽根吉紀, 中村健二, 齊藤徹, 粟津稔

電気学会産業応用部門大会(CD-ROM)　2023　2023
Design ana Analysis of 3kVA Orthogonal-Core-type Variable Inductor with Permanent Magnets

会津翔太, 中村健二, 大日向敬, 有松健司

日本磁気学会学術講演概要集　47th　2023

ISSN： 1882-2959
Magnet Arrangement of Concentrated-Winding Interior Permanent Magnet Motor with Nd-Fe-B and Ferrite Magnets

尾花輝哉, 中村健二

日本磁気学会学術講演概要集　47th　2023

ISSN： 1882-2959
Examination of Air Gap Flux Density Waveforms of Flux-Modulated-type Magnetic Gear

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日本磁気学会学術講演概要集　47th　2023

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Basic Examination of Instantaneous Torque Control for High-speed SR Motor

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Experimental Verification of Loss Dependence on Torque and Speed in Flux-modulated-type Magnetic Gear

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日本磁気学会学術講演概要集　47th　2023

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Magnetic-Properties Measurement Under DC-Biased Conditions Using Simple Waveform Control Method by myRIO

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電気学会基礎・材料・共通部門大会(Web)　2023　2023
Basic Examination on Magnetic Circuit Analysis for Variable Magnetized Magnet Considering Magnetic Hysteresis Behavior

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磁気ヒステリシスと磁気余効が加速器用電磁石の発生磁場に与える影響に対する実験的検討—Experimental Study on Influence of Magnetic Hysteresis and Magnetic After Effect Phenomena on Magnetic Field Generated by Particle Accelerator Electromagnets—静止器/回転機合同研究会・電磁界数値計算技術とその応用

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Experimental Study on Influence of Magnetic Hysteresis and Magnetic After Effect Phenomena on Magnetic Field Generated by Particle Accelerator Electromagnets

浦田知希, 恩知誼武, 菅原賢悟, 羽根吉紀, 中村健二, 石禎浩

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Various Examinations on Calculation Accuracy of DC Hysteresis Characteristics by LLG Equation

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Characteristics Calculation of Cross-Core-type Variable Inductor Based on Reluctance Network Analysis

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Applied Magnetics to Achieve Carbon Neutrality as Underlying Technologies

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電気学会研究会資料(Web)　(RM-22-112-120)　2022
Expanding the Operating Range of Axial-Flux type SR Motor for Compact EV

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電気学会研究会資料(Web)　(RM-22-112-120)　2022
Examination of Torque-to-Weight Ratio Improvement of over 10 MW class Magnetic Gear

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電気学会研究会資料(Web)　(MAG-22-102-120/MD-22-120-138/LD-22-073-091)　2022
Unbalanced Current Improvement of Transverse Flux type SR motors focusing on the Number of Phases

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電気学会研究会資料(Web)　(MAG-22-089-101/MD-22-107-119/LD-22-060-072)　2022
Reduction of Eddy Current Loss in Magnets of Flux Reversal Motor

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羽根吉紀, 三ツ谷和秀, 中村健二

電気学会研究会資料　(SA-21-001-014/RM-21-001-014)　2021
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羽根吉紀, 内山裕太郎, 中村健二

電気学会研究会資料(Web)　(SA-21-066-081/RM-21-087-102)　2021
Iron Loss Calculation of Interior Permanent Magnet Motor Considering Carrier Harmonics by Using Reluctance Network Model Representing Dynamic Hysteresis Characteristics

羽根吉紀, 内山祐太郎, 中村健二

電気学会研究会資料(Web)　(SA-21-066-081/RM-21-087-102)　2021
A Consideration on Calculation Accuracy of Simplified LLG Equation

渡部樹, 羽根吉紀, 中村健二

電気学会基礎・材料・共通部門大会(Web)　2021　2021
Development of Magnetic-Properties Measurement System Using Simple Waveform Control Technique

川口正隆, 羽根吉紀, 中村健二

電気学会基礎・材料・共通部門大会(Web)　2021　2021
Analysis of Various Core Materials by Using Magnetic Circuit Model Representing Dynamic Hysteresis Characteristics

羽根吉紀, 中村健二

電気学会基礎・材料・共通部門大会(Web)　2021　2021
A Novel Transverse-Flux type SR Motor with Permanent Magnets for applying Reverse Bias Magnetic Field on the Rotor

永井歩美, 中村健二

電気学会研究会資料　(MAG-21-043-053)　2021
Basic Characteristics of Transverse-Flux-type Switched Reluctance Motor with Permanent Magnets applying Reverse Bias Magnetic Field

永井歩美, 三ツ谷和秀, 中村健二

日本磁気学会学術講演概要集　45th　2021

ISSN： 1882-2959
A Novel Reluctance Network Analysis for Open Magnetic Circuits

2020　(55)　103-108　2020/09/03
Publisher: 電気学会
A Novel Reluctance Network Analysis for Open Magnetic Circuits

2020　(31)　103-108　2020/09/03
Publisher: 電気学会
Basic Study of Magnetostriction Force Calculation for Transformer Core based on Reluctance Network Analysis

羽根吉紀, 中村健二, 栗田直幸

電気学会研究会資料　(SA-20-001-015/RM-20-001-015)　2020
Analysis of DC-Biased Reactor Using Magnetic Circuit Model Combined with Play Model

細野雄也, 羽根吉紀, 中村健二

電気学会研究会資料　(SA-20-001-015/RM-20-001-015)　2020
Recent Advances in Iron Loss Calculation based on Magnetic Circuit Method

中村健二, 羽根吉紀

電気学会全国大会講演論文集(CD-ROM)　2020　2020
Hysteresis Analysis of Several Kinds of Core Materials based on Magnetic Circuit Method Incorporating Play Model and Cauer’s Equivalent Circuit Theory

羽根吉紀, 中村健二

電気学会研究会資料　(SA-20-031-050/RM-20-055-074)　2020
A Consideration of Magnetostriction Force Calculation for Transformer Core by Using Reluctance Network Analysis

羽根吉紀, 中村健二, 栗田直幸

日本磁気学会学術講演概要集　44th　2020

ISSN： 1882-2959
RNA Model combined with Play Model for Three-Phase-Laminated-Core Variable Inductor

羽根吉紀, 中村健二, 大日向敬, 有松健司

電気学会研究会資料　(MAG-19-001-008)　2019
Reluctance network analysis method incorporating play model

羽根吉紀, 中村健二

電気学会研究会資料　(SA-19-001-015/RM-19-001-015)　2019
プレイモデルとCauer回路を取り入れた磁気回路モデルを用いたマイナーループの算定精度向上に関する検討

羽根吉紀, 中村健二

電気学会基礎・材料・共通部門大会講演論文集(CD-ROM)　2019　2019
Magnetic Circuit Analysis by using Play Model and Cauer’s Equivalent Circuit Theory

羽根吉紀, 中村健二

電気学会研究会資料　(SA-19-055-072/RM-19-075-092)　2019
Improvement of Prediction Accuracy of Magnetic Properties of Iron Core in Heavy Rolling Process by using LLG Equation

羽根吉紀, 中村健二, 川瀬剛志, 細川徳一, 栗本直規

電気学会研究会資料　(SA-19-055-072/RM-19-075-092)　2019
磁気ヒステリシスを考慮可能な磁気回路モデルを用いた直流重畳リアクトルの解析

細野雄也, 羽根吉紀, 中村健二

電気関係学会東北支部連合大会講演論文集(CD-ROM)　2019　2019
Magnetic Circuit Model by using Play Model and Cauer’s Equivalent Circuit Theory

羽根吉紀, 中村健二

電気学会研究会資料　(MAG-19-170-181.183-196)　2019
LLG方程式を用いた磁気特性の加工による変化の予測精度向上に関する検討

羽根吉紀, 中村健二, 川瀬剛志, 細川徳一, 栗本直規

日本磁気学会学術講演概要集　43rd　2019

ISSN： 1882-2959
RNA Model combined with Play Model for Permanent Magnet Motor

羽根吉紀, 中村健二

電気学会研究会資料　(MAG-18-013-015.017-021)　2018
LLG方程式を利用した鉄心加工劣化予測手法に関する検討

羽根吉紀, 中村健二, 吉岡卓哉, 川瀬剛志, 石川智一

日本磁気学会学術講演概要集　42nd　2018

ISSN： 1882-2959
Prediction Method of Magnetic Properties in Motor Core due to Machining Process by using LLG Equation

羽根吉紀, 中村健二, 吉岡卓哉, 川瀬剛志, 石川智一

電気学会研究会資料　(RM-18-119-123.125-126.128.130-131.133-139)　2018
Experimental Verification of HVDC Transmission System for Offshore Wind Power Generation by using a Small-Scale Simulation Apparatus

2017　(134)　13-18　2017/10/19
Publisher: 電気学会
Basic Study for Applying Play Model to Reluctance Network Analysis

2017　(126)　1-5　2017/10/18
Publisher: 電気学会
Basic Characteristics of Three-Dimensional Concentric-Winding type Three-Phase Variable Inductor

2017　(14)　7-12　2017/02/24
Publisher: 電気学会
Development of a Magnetic Flux Control Type Variable Inductor and application for Voltage regulator

2017　(14)　1-6　2017/02/24
Publisher: 電気学会
Electromagnetic and Motion-coupled Analysis for Full-pitch Winding Switched Reluctance Motor Based on Reluctance Network Analysis

2017　(14)　53-58　2017/02/24
Publisher: 電気学会
Calculation of Characteristics of Field-Winding type Claw-Pole Motor based on Reluctance Network Analysis

2017　(14)　65-69　2017/02/24
Publisher: 電気学会
Magnetic Circuit Analysis under High Magnetic Flux Density Region by using Play Model obtained from LLG Equation

2017　(1)　37-42　2017/02/23
Publisher: 電気学会
Development of High-Speed SR Motor for Electric Power Tools

2017　(1)　1-6　2017/02/23
Publisher: 電気学会
Eddy Current Loss Analysis considering Magnetic Particle in Soft Magnetic Composite

2017　(1)　25-30　2017/02/23
Publisher: 電気学会
Prototype Evaluation of High-Speed SR Motor for Electric Power Tools

2015　(140)　35-39　2015/10/21
Publisher: 電気学会
Prototype Tests of In-wheel type Magnetic-Geared Motor

2014　(129)　91-95　2014/10/30
Publisher: 電気学会
Unified Calculation Method for Motor Torque in Reluctance Network Analysis

2014　(111)　43-48　2014/10/29
Publisher: 電気学会
Consideration of Axial-Gap-type Magnetic-Geared Motor

2013　(125)　89-94　2013/11/14
Publisher: 電気学会
A Consideration of the Optimum Configuration of Flux-Modulated type Dual-Axis Motor

2013　(125)　95-100　2013/11/14
Publisher: 電気学会
Efficiency optimization of SPM motor including carrier harmonics based on electric and magnetic networks

2013　(107)　15-20　2013/11/13
Publisher: 電気学会
Efficiency Improvement and Torque Ripple Reduction of Axial-Gap-type PM Motor

TAKEMAE Toshiaki, NAKAMURA Kenji, ICHINOKURA Osamu

2013　(15)　25-29　2013/03/28
Loss Analysis and Efficiency Improvement of Planetary type Magnetic Gear

FUKUOKA Michinari, NAKAMURA Kenji, ICHINOKURA Osamu

2013　(15)　13-18　2013/03/28
Basic Consideration of Magnetic Circuit Analysis Incorporating LLG Equation

TANAKA Hideaki, NAKAMURA Kenji, ICHINOKURA Osamu

2012　(102)　37-41　2012/10/29
Iron Loss Estimation under Square Wave Excitation Based on Magnetic Circuit Model Considering Anomalous Eddy Current Loss

FUJITA Kentaro, NAKAMURA Kenji, ICHINOKURA Osamu

2012　(102)　31-36　2012/10/29
Calculation of Characteristics of Three-dimensional Three-Phase Variable Inductor based on RNA

NAGAO Mariko, NAKAMURA Kenji, OHINATA Takashi, ARIMATSU Kenji, SHIRASAKI Takashi, ICHINOKURA Osamu

2012　(109)　7-12　2012/10/29
Development of Super-Multipolar Permanent Magnet Reluctance Generator designed for Small-Scale Wind-Turbine and Micro-Hydroelectric Power Generations

NAKAMURA Kenji, ICHINOKURA Osamu

2012　(54)　31-36　2012/10/04
Eddy Current Loss Calculation in Permanent Magnet Using a Reluctance Network Analysis Model of SPM motor

YOSHIDA Yukihiro, NAKAMURA Kenji, ICHINOKURA Osamu

2012　(23)　1-5　2012/03/29
Magnetic Circuit Model Considering Anomalous Eddy Current Loss

FUJITA Kentaro, NAKAMURA Kenji, ICHINOKURA Osamu

2012　(23)　49-53　2012/03/29
Basic Examination of Switched Reluctance Motor with Auxiliary Windings and Permanent Magnets

HASEGAWA Yu, NAKAMURA Kenji, ICHINOKURA Osamu

2012　(23)　13-18　2012/03/29
Basic Characteristics of the Switched Reluctance Motor with Auxiliary Windings and Permanent Magnets

HASEGAWA Yu, NAKAMURA Kenji, ICHINOKURA Osamu

2011　(94)　121-126　2011/10/26
Consideration of Optimal Design Method of Magnetic Gear based on Reluctance Network Analysis

FUKUOKA Michinari, NAKAMURA Kenji, ICHINOKURA Osamu

2011　(94)　31-36　2011/10/26
A Method for Calculating Eddy Current Loss in Permanent Magnet of PM Motor Based on Electric and Magnetic Networks

YOSHIDA Yukihiro, NAKAMURA Kenji, ICHINOKURA Osamu

2011　(94)　79-83　2011/10/26
Calculation of Characteristics of 18-legs type Three-Phase Laminated-Core Variable Inductor

NAGAO Mariko, NAKAMURA Kenji, ARIMATSU Kenji, OHINATA Takashi, SHIRASAKI Takashi, ICHINOKURA Osamu

2011　(62)　13-17　2011/10/24
Magnetic Circuit Model Considering DC Hysteresis

FUJITA Kentaro, NAKAMURA Kenji, ICHINOKURA Osamu

2011　(62)　1-5　2011/10/24
Design and Analysis of Super-Multi-Polar Permanent Magnet Reluctance Generator for Small-Scale Wind -Turbine Generation

NAKAMURA Kenji, ICHINOKURA Osamu

2011　(47)　19-23　2011/09/16
Examination of Performance Improvement of Magnetic Gear Using Polar Anisotropic Bonded Magnets

FUKUOKA Michinari, NAKAMURA Kenji, ICHINOKURA Osamu

2011　(47)　13-17　2011/09/16
A Method for Calculating Eddy Current Loss in Permanent Magnet of SPM Motor Based on Electric and Magnetic Networks

YOSHIDA Yukihiro, NAKAMURA Kenji, ICHINOKURA Osamu

2011　(47)　7-11　2011/09/16
A Method for Calculating Eddy Current Loss Distribution by RNA Considering the Magnetic Reaction Field

YOSHIDA Yukihiro, NAKAMURA Kenji, ICHINOKURA Osamu

2011　(8)　7-11　2011/03/28
Loss Analysis of an SR Motor made of Permendur based on Experiments

HASEGAWA Yu, NAKAMURA Kenji, ICHINOKURA Osamu

2011　(1)　1-6　2011/03/28
Calculation of Dynamic Characteristics of Surface Permanent Magnet Type Magnetic Gear by RNA and Trial Tests

FUKUOKA Michinari, NAKAMURA Kenji, ICHINOKURA Osamu

2011　(8)　13-18　2011/03/28
Experimental Verification of SR Motor Made of Fe-Co Alloy (Permendur)

HASEGAWA Yu, NAKAMURA Kenji, ICHINOKURA Osamu

2010　(142)　7-11　2010/11/25
Control System Analysis of Three-Phase Laminated-Core Variable Inductor using MATLAB/Simulink

ABE Yoshiaki, GOTO Hiroki, NAKAMURA Kenji, OHINATA Takashi, ARIMATSU Kenji, SAKAMOTO Kunio, ICHINOKURA Osamu

2010　(132)　41-45　2010/11/01
A Consideration of an Eddy Current Network Model for Reluctance Network Analysis

YOSHIDA Yukihiro, NAKAMURA Kenji, ICHINOKURA Osamu

2010　(132)　17-22　2010/11/01
Development of Outer-Rotor type Permanent Magnet Reluctance Generator using Ferrite Magnet

NAKAMURA Kenji, YOSHIDA Jun, ICHINOKURA Osamu

2010　(134)　37-42　2010/10/20
Characteristics Evaluation of an SR Motor Made of Permendur by Experiments

HASEGAWA Yu, NAKAMURA Kenji, ICHINOKURA Osamu

2010　(134)　31-35　2010/10/20
Magnetic Circuit Model of Permanent Magnet Motor Applicable for Controller Design

KAWANO Yosuke, GOTO Hiroki, NAKAMURA Kenji, ICHINOKURA Osamu

2010　(116)　41-46　2010/10/20
Iron Loss Calculation of IPM Motor based on RNA

SUZUKI Kuniaki, NAKAMURA Kenji, ICHINOKURA Osamu

2010　(58)　11-15　2010/03/29
Basic Characteristic of Axial-Gap type SR Motor

ONO Yuki, NAKAMURA Kenji, ICHINOKURA Osamu

2010　(58)　17-21　2010/03/29
Power Magnetics DevicesII Static Devices

Osamu Ichinokura, Kenji Nakamura

Magnetics Japan　5　(3)　142-149　2010/03
Publisher: The Magnetic Society of Japan
ISSN： 1880-7208
Power conditioner for a small hydropower generator (result of test in field)

2010　419-422　2010
Publisher: 日本太陽エネルギー学会
Examination of Core Material of Three-Phase Laminated-Core Variable Inductor

ABE Yoshiaki, NAKAMURA Kenji, OHINATA Takashi, ARIMATSU Kenji, SAKAMOTO Kunio, ICHINOKURA Osamu

2009　(129)　1-6　2009/10/29
Calculation of cogging and iron loss of PM motor based on simple magnetic circuit

KAWANO Yosuke, NAKAMURA Kenji, ICHINOKURA Osamu

2009　(129)　25-30　2009/10/29
RNA Model of 4/2 SR Motor for High Speed Application

YAMAUCHI Takahiro, GOTO Hiroki, NAKAMURA Kenji, ICHINOKURA Osamu

2009　(129)　49-54　2009/10/29
A Way to Reducing Magnet Loss of Permanent-Magnet Magnetic Gears

IKEDA Tetsuya, NAKAMURA Kenji, ICHINOKURA Osamu

2009　(32)　55-59　2009/05/15
Trend of Simulation Technique in Magnetic Applications

ICHINOKURA Osamu, TAJIMA Katsubumi, NAKAMURA Kenji

2009　(23)　1-6　2009/03/26
Design Optimization of SR Motor Made of Permendur Based on Design of Experiment

HASEGAWA Yu, NAKAMURA Kenji, ICHINOKURA Osamu

2009　(23)　13-18　2009/03/26
The construction of the analysis model of Interior Permanent Magnet Synchronous Motor (IPMSM) using Reluctance Network Analysis (RNA)

HASEGAWA Tatsuya, GOTO Hiroki, NAKAMURA Kenji, ICHINOKURA Osamu

2008　(108)　1-5　2008/11/13
A Consideration of Design method of a Claw Teeth Motor Based on Three-Dimensional Reluctance Network Analysis

MIZUGUCHI Takahiro, MIYASHITA Tomoaki, NAKAMURA Kenji, KOYAMA Takayuki, ICHINOKURA Osamu

2008　(108)　61-66　2008/11/13
Operating Simulation of Claw Teeth Motor based on Reluctance Network Analysis

MIYASHITA Tomoaki, MIZUGUCHI Takahiro, NAKAMURA Kenji, ICHINOKURA Osamu

2007　(123)　75-80　2007/10/18
Development of a Switched Reluctance Motor with Permanent Magnets between the Stator Pole-Tips

NAKAMURA Kenji, MUROTA Kohei, ICHINOKURA Osamu

2007　(123)　69-74　2007/10/18
Calculation of Characteristics of a Magnetic Gear by Reluctance Network Analysis

TASHIRO Toshiaki, NAKAMURA Kenji, ICHINOKURA Osamu

2007　(90)　19-23　2007/10/04
Simulation of DC Micro Grid System Using Permanent Magnetic Reluctance Generator by Magnetic Circuit

KUBOTA Masayuki, GOTO Hiroki, NAKAMURA Kenji, ICHINOKURA Osamu

2007　(90)　25-30　2007/10/04
A Consideration of the reduction in torque ripple by a stacked PMRG

YOSHIDA Jun, NAKAMURA Kenji, ICHINOKURA Osamu

2007　(90)　31-36　2007/10/04
Calculation of Characteristics of the Three-Phase Variable Inductor

NAKAMURA Kenji, HISADA Shuhei, ARIMATSU Kenji, OHINATA Takashi, SATO Yoshihiko, ICHINOKURA Osamu

2007　(16)　37-42　2007/03/29
A Consideration of Permanent Magnet type Multipolar Reluctance Generator based on Numerical Simulation

TASHIRO Toshiaki, NAKAMURA Kenji, ICHINOKURA Osamu

2006　(112)　1-6　2006/10/06
Calculation of Characteristics of a VR type Stepping Motor based on Reluctance Network Analysis

MIYASHITA Tomoaki, NAKAMURA Kenji, WATANABE Tadaaki, ICHINOKURA Osamu

2006　(103)　13-18　2006/10/05
Characteristics of a Three-Phase Reluctance Generator Using Stator Core with Permanent Magnet and Basic Considerations of a Multipolar Reluctance Generator

ICHINOKURA Osamu, ONO Tomoya, TASHIRO Toshiaki, NAKAMURA Kenji

2006　(11)　33-38　2006/03/07
Operating Simulation of a Stepping Motor Based on Reluctance Network Analysis

MIYASHITA Tomoaki, NAKAMURA Kenji, ICHINOKURA Osamu

2006　(11)　39-44　2006/03/07
Consideration of Analytical Domain for an RNA model of an EIE-core

TOMONAGA Takeshi, NAKAMURA Kenji, AKATSUKA Shigeaki, ARIMATSU Kenji, OHINATA Takashi, SATO Yoshihiko, ICHINOKURA Osamu

2006　(11)　21-26　2006/03/07
Development of an Outer-Rotor-Type Multipolar SR Motor and Its Application in an Electric Vehicle

Osamu Ichinokura, Hiroki Goto, Kenji Nakamura, Tadaaki Watanabe

Magnetics Japan　1　(1)　13-18　2006/01
Publisher: The Magnetic Society of Japan
ISSN： 1880-7208
Experiment and Consideration of Switched Reluctance Generators

ICHINOKURA Osamu, TAKAHASHI Atsushi, GOTO Hiroki, NAKAMURA Kenji, WATANABE Tadaaki

23　251-252　2005/08/01
A Novel Switched Reluctance Motor with C-Shaped Wound-Cores

ONO Tomoya, NAKAMURA Kenji, ICHINOKURA Osamu

2005　(24)　7-12　2005/06/08
An Examination of a Method for Calculating Iron loss of an SR Motor Based on Reluctance Network Analysis

FUJIO Shinya, NAKAMURA Kenji, ICHINOKURA Osamu

2005　(24)　19-24　2005/06/08
Exciting Circuit and Generation Characteristics of Switched Reluctance Generators

TAKAHASHI Atsushi, GOTO Hiroki, NAKAMURA Kenji, WATANABE Tadaaki, ICHINOKURA Osamu

2005　(24)　1-6　2005/06/08
SPICE Simulation of Interior Permanent Magnet Motor Considering Nonlinear Magnetization Characteristics

ISHIHARA Masahiro, NAKAMURA Kenji, ICHINOKURA Osamu

IEEJ Technical Meeting on Rotating Machinery　2004　(125)　43-48　2004/10/07
Calculation Method for Characteristics of Permanent Magnet Generator Based on Reluctance Network Analysis

NAKAMURA Kenji, LI Hu, ICHINOKURA Osamu

2004　(98)　31-36　2004/10/06
Basic Characteristics of Reluctance Generator with Permanent Magnets Buried in Stator Core

ICHINOKURA O., SHIDA J., NAKAMURA K., WATANABE T.

28　451-451　2004/09/21
Calculation of Characteristics of Outer-Rotor Type Multipolar SR Motor for Electric Vehicle

NAKAMURA K., SUZUKI Y., GOTO H., ICHINOKURA O.

28　455-455　2004/09/21
Calculation of Characteristics of Permanent Magnet Generator Using Reluctance Network Analysis

NAKAMURA K., LI H., ICHINOKURA O.

28　452-452　2004/09/21
Dynamic Characteristics Computation of Switched Reluctance Motor Based on Nonlinear Reluctance Network Analysis

NAKAMURA Kenji, KIMURA Koshiro, ICHINOKURA Osamu

2004　(47)　1-6　2004/06/17
Dynamic Characteristic Computation of Switched Reluctance Motor Based on Reluctance Network Analysis

NAKAMURA Kenji, KIMURA Koshiro, ICHINOKURA Osamu

2004　(57)　7-12　2004/03/16
A consideration on the application of Switched Reluctance Motor to Electric Tools

IWATA Kazutaka, NAKAMURA Kenji, ICHINOKURA Osamu

2004　(57)　29-34　2004/03/16
Dynamic Analysis of Interior Permanent Magnet Motor Considering Nonlinear Magnetization Characteristics

SAITO Kenichi, ISHIHARA Masahiro, NAKAMURA Kenji, ICHINOKURA Osamu

2004　(57)　19-24　2004/03/16
Magnetic Circuit Model of a Switched Reluctance Motor Considering a Magnetic Saturation

NAKAMURA Kenji, KIMURA Koshiro, ICHINOKURA Osamu

2003　(87)　7-12　2003/10/08
Considerations on the Multipolar Switched Reluctance Motors

SUZUKI Yosuke, NAKAMURA Kenji, ICHINOKURA Osamu

2003　(87)　1-6　2003/10/08
Dynamic Analysis of Interior Permanent Magnet Synchronous Motor Based on Magnetic Circuit Methods

SAITO K., NAKAMURA K., ICHINOKURA O.

27　143-143　2003/09/01

ISSN： 1340-8100
A Study on Exciting Methods of SRM Based on Electric Circuit-Magnetic Field Coupled Analysis

GOTO H., SHIDA J., NAKAMURA K., GUO H. J., ICHINOKURA O.

27　145-145　2003/09/01

ISSN： 1340-8100
Simple Magnetic Circuit Model of SRM Considering Magnetic Saturation

NAKAMURA K., KIMURA K., ICHINOKURA O.

27　140-140　2003/09/01

ISSN： 1340-8100
Electromagnetic and Thermal Coupled Analysis of Ferrite Orthogonal Core

NAKAMURA K., YOSHIDA H., ICHINOKURA O.

27　35-35　2003/09/01

ISSN： 1340-8100
Method for expressing the magnetic hysteresis in the nonlinear reluctance for SPICE

KIMURA K., NAKAMURA K., ICHINOKURA O.

27　40-40　2003/09/01

ISSN： 1340-8100
Operating Characteristics of EIE-Core type Variable Inductor Based on Three-Dimensional Magnetic Circuit

HAYAKAWA S., NAKAMURA K., AKATUKA S., AOKI T., KAWAKAMI M., OHINATA T., MINAZAWA K., ICHINOKURA O.

27　36-36　2003/09/01

ISSN： 1340-8100
Electromagnetic and Thermal Coupled Analysis of Ferrite Orthogonal Core for Switching Power Supplies

NAKAMURA Kenji, YOSIDA Hirokazu, ICHINOKURA Osamu

Technical report of IEICE. Energy engineering in electronics and communications　103　(200)　19-24　2003/07/18
Publisher: The Institute of Electronics, Information and Communication Engineers
ISSN： 0913-5685

More details Close

An orthogonal core can continuously control a net inductance of winding. Recently the orthogonal core variable inductor has been applied to a high-frequency switching power supply. An optimum design method of the variable inductor for high-frequency applications is therefore necessary. We previously proposed an analysis method based on Reluctance Network Analysis (RNA) for a silicon steel orthogonal core used in the commercial frequency region. In order to use the orthogonal core in the high-frequency region, we must consider a temperature rise of cores due to copper and iron losses. In this paper, we calculate the iron losses in a ferrite orthogonal core variable inductor for switching power supplies based on RNA, and estimate a core temperature on the basis of a thermal equivalent circuit.
Calculation of Fundamental Characteristics of Linear Variable Inductor using EIE-Core

NAKAMURA Kenji, KOBAYASHI Toshimi, AKATSUKA Shigeaki, AOKI Tomoyuki, KAWAKAMI Mineo, OHINATA Takashi, MINAZAWA Kazuo, ICHINOKURA Osamu

2002　(176)　27-32　2002/11/30
Examination of Iron Loss and Temperature Analysis Method of Ferrite Orthogonal-Core for High Frequency Region

YOSHIDA Hirokazu, NAKAMURA Kenji, ICHINOKURA Osamu

2002　(176)　11-16　2002/11/30
Dynamic Analysis of Interior Permanent Magnet Motor using a Magnetic Circuit Model

SAITO K., NAKAMURA K., ICHINOKURA O.

2002　(166)　39-44　2002/11/29
Consideration on Calculation Method for Iron loss Characteristics of SRM using Simple Magnetic Circuit Model

NAKAMURA Kenji, KIMURA Koshiro, ICHINOKURA Osamu

2002　(108)　11-16　2002/10/17
Considerations in distribution of flux density inside brushless DC motor using RNA (Reluctance Network Analysis)

MATSUSHITA Satoshi, NAKAMURA Kenji, ICHINOKURA Osamu

2002　(94)　29-34　2002/10/16
Magnetic circuit model of distributed winding type blushless DC motor for RNA

MATSUSHITA S., NAGAO H., NAKAMURA K., ICHINOKURA O.

26　317-317　2002/09/01

ISSN： 1340-8100
Iron loss calculation of SRM using simple magnetic circuit model

NAKAMURA K., KIMURA K., ICHINOKURA O.

26　319-319　2002/09/01

ISSN： 1340-8100
Calculation of characteristics of gapless linear variable inductor using RNA

NAKAMURA K., AKATSUKA S., AOKI T., KAWAKAMI M., OHINATA T., SATO H., ICHINOKURA O.

26　453-453　2002/09/01

ISSN： 1340-8100
Consideration of Iron Loss and Temperature Analysis of Ferrite Orthogonal-Core for High Frequency Region

YOSHIDA H., NAKAMURA K., ICHINOKURA O.

26　457-457　2002/09/01

ISSN： 1340-8100
Calculation of Characteristics of Ferrite Pot Core Type Non-Contact Transformer by RNA

ITO M., NAKAMURA K., ICHINOKURA O.

26　458-458　2002/09/01

ISSN： 1340-8100
Dynamic Analysis of Distribute Winding Brushless DC Motor using RNA Method

NAGAO Hiroki, KIMURA Gen, NAKAMURA Kenji, ICHINOKURA Osamu

2001　(107)　13-17　2001/10/24
Analysis of Operating Characteristics of Orthogonal-Core Type Phase Sifter

NAKAMURA K., AKATSUKA S., OHINATA T., KAWAKAMI M., MAEDA M., SATO H., ICHINOKURA O.

25　224-224　2001/09/01

ISSN： 1340-8100
Calculation of Characteristics of Magnetic Flux Control Type Transformer

NAKAMURA K., AKATSUKA S., OHINATA T., MAEDA M., SATO H., ICHINOKURA O.

25　227-227　2001/09/01

ISSN： 1340-8100
Core Temperature Analysis of Ferrite Orthogonal-Core for High Frequency Region Based on Thermal Resistance Circuit

NAKAMURA K., YOSHIDA H., YOSHIDA H., ICHINOKURA O.

25　225-225　2001/09/01

ISSN： 1340-8100
Analysis of Orthogonal-Core Type SVC Using EMTP

FUJITA S., NAKAMURA K., MAEDA M., SATO H., ICHINOKURA O.

25　226-226　2001/09/01

ISSN： 1340-8100
A Consideration on the Vibration of SRM Based on Magnetic and Structural Analyses

SUZUKI K., NAKAMURA K., ICHINOKURA O.

25　308-308　2001/09/01

ISSN： 1340-8100
Analysis of Performance Characteristics of Linear Parametric Motor Based on RNA Methed

YAMANAKA Y., KIKUCHI S., WATANABE T., NAKAMURA K., ICHINOKURA O.

25　304-304　2001/09/01

ISSN： 1340-8100
Dynamic Analysis of Blushless DC Motor Dynamics Using Magnetic Circuit

25　309-309　2001/09/01

ISSN： 1340-8100
Analysis of Blushless DC Motor Dynamics Using Magnetic Circuit

2001　(49)　65-70　2001/06/20
Basic Considerations on Vibration Analysis of 6/4 Switched Reluctance Motor

SUZUKI Koji, NAKAMURA Kenji, ICHINOKURA Osamu

2001　(49)　25-30　2001/06/20
SPICE Simulation of SRM Considered with Nonlinear Magnetization Characteristics

TSUKII Tomoyuki, NAKAMURA Kenji, WATANABE Tadaaki, ICHINOKURA Osamu

2000　(110)　115-120　2000/10/19
Calculation of Characteristics of Parallel Laminated Orthogonal-Core Type Variable Inductor

NAKAMURA Kenji, AKATSUKA Shigeaki, OHINATA Takashi, KAWAKAMI Mineo, MAEDA Mitsuru, SATO Hiromichi, ICHINOKURA Osamu

2000　(167)　61-66　2000/09/25
Development of Magnetic Flux Control Type Variable Inductor

AKATSUKA S., OHINATA T., KAWAKAMI M., MAEDA M., SATO H., NAKAMURA K., ICHINOKURA O.

24　464-464　2000/09/01

ISSN： 1340-8100
Shape Effect of Wedge Gap in Orthogonal-Core Type Variable Inductor

NAKAMURA K., KAWAKAMI M., MAEDA M., SATO H., ICHINOKURA O.

24　466-466　2000/09/01

ISSN： 1340-8100
Characteristics of Orthogonal-Core Type Variable Inductor in 200kHz〜550kHz

YOSHIDA Hiroshi, WATANABE Tadaaki, NAKAMURA Kenji, ICHINOKURA Osamu

24　467-467　2000/09/01

ISSN： 1340-8100
Fundamental Operation of Orthogonal-Core Type Variable Inductor with Third Winding

NAKAMURA K., KAWAKAMI M., MAEDA M., SATO H., ICHINOKURA O.

24　465-465　2000/09/01

ISSN： 1340-8100
SPICE Model of Non-Linear Reluctance for Analysis of Switched Reluctance Motor

NAKAMURA K., TSUKII T., ICHINOKURA O.

24　456-456　2000/09/01

ISSN： 1340-8100
Basic Consideration of Series Compensation Using The Orthogonal-Core

NAKAMURA Kenji, KAWAKAMI Mineo, AKATSUKA Shigeaki, MAEDA Mitsuru, SATO Hiromichi, ICHINOKURA Osamu

2000　(103)　19-24　2000/05/26
A Connection Methods of Primary Winding of The Orthogonal-Core with Wedge Gap of AVR.

NAKAMURA K., KAWAKAMI M., AKATSUKA S., MAEDA M., ICHINOKURA M.

23　344-344　1999/10/01
無効電力制御形AVR用直交磁心の解析

中村健二, 一ノ倉理, 前田満, 川上峰夫, 伊藤高之

電気設備学会全国大会講演論文集　16　105-106　1998/09/01
Calculation of Orthogonal-Core Type Variable Inductor with Wedge Gap

NAKAMURA K., TAJIMA K., KAWAKAMI M., MAEDA M., ITO T., ICHINOKURA O.

22　172-172　1998/09/01
Calculation of Orthogonal-Core with Wedge Gap

NAKAMURA Kenji, TAJIMA Katsubumi, MAEDA Mitsuru, KAWAKAMI Mineo, SATO Hiromichi, ITO Takayuki, SAITO Tsuyoshi, ICHINOKURA Osamu

1998　(118)　49-53　1998/08/27

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Books and Other Publications 8

磁気回路法によるモータの解析技術

一ノ倉理, 田島克文, 中村健二, 吉田征弘

科学情報出版　2016/12/30
パワーマグネティックスのための応用電磁気学

日本磁気学

共立出版　2015/11/25
特殊同期機の現状と将来動向

特殊同期機の現状と将来動向調査専門委員会

電気学会　2014/02
改訂磁気工学の基礎と応用

電気学会マグネティックス技術委員会

コロナ社　2013/10
電気工学ハンドブック第7版

電気学会

電気学会　2013/09

ISBN: 9784274213823
電力用磁気デバイスの最新動向

電力用磁気デバイスの高機能化技術調査専門委員会

電気学会　2013/01
磁気応用におけるシミュレーション技術

磁気応用におけるシミュレーションツール活用技術調査専門委員会

電気学会　2010/09
永久磁石同期機の定数決定法と特性算定技術

永久磁石同期機の特性算定技術調査専門委員会

電気学会　2010/04

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Presentations 42

Efficiency Improvement of Magnetic-Geared Motor by Open-Slot and Interior Permanent Magnet Structure International-presentation

NAKAMURA Kenji

2018/04/26
A Novel 3-D Concentric-Winding-Type Three-Phase Variable Inductor for Reactive Power Compensation in Electric Power Systems International-presentation

IEEE International Magnetic Conference (INTERMAG2017)　2017/04/25
Development of high-speed switched reluctance motor for electric power tools International-presentation

JEMS 2016　2016/08/21
High-Efficiency Magnetic Gear and Developing Magnetic-Geared Motor International-presentation

The 4th International Conference of Asian Union of Magnetics Societies (IcAUMS 2016)　2016/08/01
Design and Analysis of 6.6 kVA - 100 kVA Concentric- Winding type Three-Phase Variable Inductor based on Reluctance Network Analysis International-presentation

The 13th Joint MMM-Intermag Conference　2016/01/11
Development of High-Speed 12/8-pole Switched Reluctance Motor for Electric Power Tools International-presentation

The 13th Joint MMM-Intermag Conference　2016/01/11
Development of Concentric-Winding type Three-Phase Variable Inductor International-presentation

IEEE International Magnetic Conference (INTERMAG2015)　2015/05/11
Design Strategy of Lap-Winding type Three-Phase Variable Inductor International-presentation

The 59th Annual Magnetism and Magnetic Materials (MMM) Conference　2014/11/03
Novel Interior Permanent Magnet Motor with Rare-Earth and Ferrite Magnets in a Flux-Barrier type Outer Rotor International-presentation

IEEE International Magnetic Conference (INTERMAG2014)　2014/05/05
Performance Improvement of Magnetic Gear and Comparison with Conventional Mechanical Gear International-presentation

The 58th Annual Magnetism and Magnetic Materials (MMM) Conference　2013/11/04
Magnetic-Circuit-Based Iron Loss Estimation under Square Wave Excitation with Various Duty Ratios International-presentation

The 12th Joint MMM-Intermag Conference　2013/01/14
Performance Improvement of the Permanent Magnet Magnetic Gear International-presentation

International Conference of the Asian Union of Magnetics Societies (ICAUMS 2012)　2012/10/02
Super-Multipolar Permanent Magnet Reluctance Generator Designed for Small-Scale Renewable Energy Generation International-presentation

The 20th International Conference on Electrical Machines (ICEM 2012)　2012/09/02
Super-Multipolar Permanent Magnet Reluctance Generator Designed for Small-Scale Wind- Turbine Generation International-presentation

IEEE International Magnetic Conference (INTERMAG2012)　2012/05/07
A Method for Controlling Three-Phase-Laminated-Core Variable Inductor Applied to Reactive Power Compensator by Voltage Reversible Chopper International-presentation

14th European Conference on Power Electronics and Applications (EPE 2011)　2011/08/30
Dynamic Simulation of Three-Phase-Laminated-Core Variable Inductor based on Magnetic Circuit Analysis International-presentation

IEEE International Magnetic Conference (INTERMAG2011)　2011/04/25
Outer-Rotor type Permanent Magnet Reluctance Generator with High Power and Low Toque Ripple International-presentation

36th Annual Conference of the IEEE Industrial Electronics Society (IECON'10)　2010/11/07
Rare-Earth Free Permanent Magnet Reluctance Generator with High Power and Efficiency International-presentation

The 2nd International Symposium on Advanced Magnetic Materials and Applications (ISAMMA2010)　2010/07/12
A Novel High Power Permanent Magnet Reluctance Generator using Ferrite Magnet International-presentation

13th European Conference on Power Electronics and Applications (EPE 2009)　2009/09/08
Iron Loss Calculation in a Three-Phase-Laminated-Core Variable Inductor Based on Reluctance Network Analysis International-presentation

IEEE International Magnetic Conference (INTERMAG2009)　2009/05/04
Dynamic Simulation of PM Motor Drive System Based on Reluctance Network Analysis International-presentation

13th International Power Electronics and Motion Control Conference (EPE-PEMC 2008)　2008/09/01
Development of a Novel Three-Phase Laminated Core Variable Inductor International-presentation

IEEE International Magnetic Conference (INTERMAG2008)　2008/05/04
Calculation of dynamic characteristics of electrical machinery based on reluctance network analysis International-presentation

APCOM '07 - EPMESC XI　2007/12/03
Characteristics of a Novel Switched Reluctance Motor having Permanent Magnets between the Stator Pole-Tips International-presentation

12th European Conference on Power Electronics and Applications (EPE 2007)　2007/09/02
Reluctance Network Analysis of an SR motor Considering Iron loss characteristics and the Optimum Direction of Excitation International-presentation

International Conference on Electrical Machines (ICEM2006)　2006/09/02
Reluctance Network Analysis Model of a Permanent Magnet Generator Considering an Overhang Structure and Iron loss International-presentation

International Conference on Electrical Machines (ICEM2006)　2006/09/02
A Method for Dynamic Analysis of an Interior Permanent Magnet Motor Based on Nonlinear Magnetic Circuit International-presentation

International Conference on Electrical Machines (ICEM2006)　2006/09/02
A Method for Calculating Iron Loss of a Switched Reluctance Motor based on Reluctance Network Analysis International-presentation

International Power Electronics and Motion Control Conference (EPE-PEMC2006)　2006/08/30
A Method for Calculating Iron Loss of an SR Motor Based on Reluctance Network Analysis and Comparison of Symmetric and Asymmetric Excitation International-presentation

IEEE International Magnetic Conference (INTERMAG2006)　2006/05/08
A Novel Switched Reluctance Motor with Wound-cores Put on Stator and Rotor Poles International-presentation

IEEE International Magnetic Conference (INTERMAG2005)　2005/04/04
Three-dimensional Reluctance Network Analysis Considering an Iron Loss Characteristic for an EIE-core Variable Inductor International-presentation

IEEE International Magnetic Conference (INTERMAG2005)　2005/04/04
Design of Outer-Rotor Type Multipolar SR Motor for Electric Vehicle International-presentation

Joint European Magnetic Symposia (JEMS'04)　2004/09/05
A New Nonlinear Magnetic Circuit Model for Dynamic Analysis of IPMSM International-presentation

Joint European Magnetic Symposia (JEMS'04)　2004/09/05
Electromagnetic and Motion Coupled Analysis for Switched Reluctance Motor Based on Reluctance Network Analysis International-presentation

Joint European Magnetic Symposia (JEMS'04)　2004/09/05
Electromagnetic and Motion Coupled Analysis for Switched Reluctance Motor Using a Nonlinear Magnetic Circuit Model International-presentation

11th International Power Electronics and Motion Control Conference　2004/09/02
Design and Analysis of an Outer-Rotor Type Multipolar SR Motor for Application to the EV International-presentation

11th International Power Electronics and Motion Control Conference　2004/09/02
Nonlinear Magnetic Circuit Model of SRM for Calculating Dynamic Flux Distribution International-presentation

The 9th Joint MMM-Intermag Conference　2004/01/05
Electromagnetic and Thirmal Coupled Analysis of Ferrite Orthogonal Core Based on Three-dimensional Reluctance and Thermal-Resistance Network Model International-presentation

The 9th Joint MMM-Intermag Conference　2004/01/05
Electric and Magnetic Simultaneous Transient Analysis Method of Switched Reluctance Motor for Use on SPICE International-presentation

The fifth International Conference on Power Electronics and Drive Systems　2003/11/15
Dynamic Analysis of Interior Permanent Magnet Motor Based on a Magnetic Circuit Model International-presentation

IEEE International Magnetic Conference (INTERMAG2003)　2003/03/30
Application of Orthogonal-Core Transformer to Series Compensation for Power System International-presentation

The 8th joint MMM - Intermag Conference　2001/01/08
Analysis of Orthogonal-Core Type Linear Variable Inductor and Application to Var Compensator International-presentation

IEEE International Magnetic Conference (Intermag2000)　2000/04/09

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Industrial Property Rights 17

電力変換装置および風力発電システム

栗田直幸, 恩田謙一, 一ノ倉理, 中村健二

特許6470645

Property Type: Patent

Holder:
回転電機

中村健二, 鈴木雄真, 大石悠平, 操谷欽吾

Property Type: Patent
磁気歯車

中村健二, 鈴木雄真, 大石悠平, 瀧川眞喜人

Property Type: Patent
磁気歯車

中村健二, 鈴木雄真, 大石悠平, 瀧川眞喜人

Property Type: Patent
磁気ギア装置

鈴木雄真, 瀧川眞喜人, 操谷欽吾, 中村健二

Property Type: Patent
三相電磁機器

大日向敬, 有松健司, 一ノ倉理, 中村健二

Property Type: Patent
三相電磁機器

大日向敬, 有松健司, 中村健二, 一ノ倉理

特許第6025059号

Property Type: Patent
磁気歯車装置

清水暢夫, 笹田哲男, 一ノ倉理, 中村健二

Property Type: Patent
三相電磁機器

大日向敬, 有松健司, 一ノ倉理, 中村健二

特許第5946177号

Property Type: Patent
駆動装置およびプラント設備

清水暢夫, 笹田哲男, 一ノ倉理, 中村健二

Property Type: Patent
磁気歯車装置

清水暢夫, 笹田哲男, 一ノ倉理, 中村健二

Property Type: Patent
三相電磁機器

大日向敬, 有松健司, 中村健二, 一ノ倉理

特許第5896371号

Property Type: Patent
磁気歯車装置

清水暢夫, 笹田哲男, 中原明仁, 一ノ倉理, 中村健二

Property Type: Patent
磁気歯車装置

清水暢夫, 笹田哲男, 中原明仁, 一ノ倉理, 中村健二

Property Type: Patent
発電装置

中村健二, 一ノ倉理

特許第5413919号

Property Type: Patent
三相電磁機器

中村健二, 一ノ倉理, 大日向敬, 佐藤佳彦, 有松健司

特許第4646327号

Property Type: Patent
可変磁気抵抗型発電装置

一ノ倉理, 中村健二

Property Type: Patent

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Research Projects 27

Creation of an in-wheel motor integrating an SR motor and magnetic gear and its application to electric vehicles

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (A)

Institution: Tohoku University

2024/04/01 - 2029/03/31
磁気的相互作用を考慮した磁気ギヤードモータのトルク式導出と小型電気自動車への応用

中村健二

Offer Organization: 日本学術振興会

System: 科学研究費助成事業

Category: 基盤研究(B)

Institution: 東北大学

2021/04/01 - 2024/03/31

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本年度は、磁気的相互作用を考慮した磁気ギヤードモータのトルク式の導出と妥当性の検証を行うとともに、磁気的相互作用が諸特性に与える影響について検討を行った。まずトルク式の導出については、磁気ギヤードモータのギヤ部とモータ部の各種磁束を同一のd-q座標上にベクトルで表し、このベクトル図からギヤ部とモータ部の磁気的相互作用を考慮したトルクの理論式を導出した。次いで、このトルクの理論式の妥当性を明らかにするため、有限要素法（FEM）による電磁界解析を用いてトルクを計算し、理論式との比較・検討を行った。その結果、両者は良好に一致した。さらに、小型の磁気ギヤードモータを用いた検証実験とも比較を行った結果、実測値とトルク式による算定値は良好に一致したことから、トルク式の妥当性が明らかとなった。次いで、磁気的相互作用が磁気ギヤードモータの力率や効率に与える影響について評価を行った。2次元FEMによる検討では、埋込磁石型（IPM）の磁気ギヤードモータは、モータ部と磁気ギヤ部の間で磁気的相互作用が生じることを明らかにした。また、磁気的相互作用の影響について、電圧方程式およびベクトル図を用いて考察し、IPMは負荷が増加すると力率が変化することを明らかにした。続いて、考察の妥当性検証のため、3次元FEMを用いてIPMの力率および効率の算定を行った。その結果、IPMは磁気的相互作用の影響で負荷の増加によって力率が変化することが明らかとなり、考察の妥当性が示された。また、効率および力率の算定結果より、IPMを高効率・高力率運転するには進み電流位相で駆動するのが良いことが明らかとなった。最後に、IPMの試作機を用いて検証実験を行った結果、測定結果と算定結果が定性的に良く一致したことから、考察の妥当性が実証された。
Research on high-speed and high-precision control methods for accelerator electromagnets with quantified magnetic hysteresis.

Sugahara Kengo

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (C)

Institution: Kindai University

2020/04/01 - 2023/03/31

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In the operation of accelerator magnets, it is necessary to consider the effect of hysteresis. The finite element method is a method to evaluate the effect of hysteresis, but it is not suitable for the operation of accelerator magnets because of its long calculation time. Therefore, the use of "reluctance networks analysis," which have a relatively low computational cost, is being considered to support the operation of accelerator magnets. In this study, the concept of the Kelvin transformation is extended to be applicable to open magnetic circuits such as accelerator magnets. The results of this research have received a paper award from the Magnetics Society of Japan. Further experimental investigation revealed that in addition to DC hysteresis, it is necessary to model hysteresis coupled with magnetic aftereffects.
脱調時に優れた再始動性を有する埋込磁石型誘導同期磁気ギヤの開発 Competitive

Offer Organization: 国立研究開発法人科学技術振興機構

System: 研究成果展開事業（研究成果最適展開支援プログラム（A-STEP））

Category: 機能検証フェーズ

Institution: 東北大学

2019/11 - 2021/03

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非接触で増減速可能な磁気ギヤは、クリーンルームや食品工場などの発塵や潤滑油を嫌う分野、風力発電や潮力発電などのメンテナンスフリーが望まれる分野で実用化が期待されている。しかしながら、磁気ギヤは過負荷によって脱調した際に、その負荷をほぼ完全に取り除かない限り、再始動ができない。そこで本研究では、磁気ギヤの回転子にかご形導体を付加することで、脱調後に再始動可能な新しい誘導同期磁気ギヤを開発する。さらに、回転子やポールピースの形状・寸法、かご形導体の材質等を最適化することで、脱調後、50％負荷以上での再始動の達成を目指す。
高伝達特性・低コストを目指した、海中自立発電向け新型IPM式磁気ギアの研究開発 Competitive

Offer Organization: 経済産業省

System: 戦略的基盤技術高度化・連携支援事業

Category: 戦略的基盤技術高度化支援事業（サポイン事業）

Institution: 株式会社プロスパイン

2017/04 - 2020/03

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変速機とはモータなどの動力源の出力を、内部歯車の回転速度を増減させて出力することで、回転速度、トルクを変える装置であり、一般的に装置産業では機械式遊星歯車が用いられている。この機械式遊星歯車は歯車部が金属同士の接触の為、低伝達効率高磨耗性等の課題を持ちつつ広範囲に各方面で使われている。近年、動力装置業界では、ネオジム永久磁石を用いた非接触式のカップリング、歯車の需要が高くなっている。装置にクリーン度が求められている業種（半導体、液晶、化学薬品、食品機械等）の内部装置として注目が高まっている。カップリング同様に変速機にも非接触化の要望が高くなっている。磁石を用いてトルク変換をする一般的な方法は、径の異なる円盤磁石を使用することである。しかしこの方法は磁石の有効活用部分が少なく、変速比によっては円盤のサイズが大きくなり、入出力の軸がずれてしまう。そのため、伝達トルクも低く、装置が大型になり、普及するに至っていない。この欠点を補う方法として、磁束変調を利用した変速機の開発が進められている。しかし依然高コストでニーズが高い割りに普及していないのが実状である。本研究では高度化目標に従い、開発を進め従来の問題点の解消を図る。具体的には磁気ギアとして多くの可能性を有するＩＰＭ型磁気ギアを採用する。そのプロセスとして 1.垂直埋め込み構造の(ＩＰＭ方式）の開発磁場解析技術で体格・特性を決定し既存製品を凌駕出来る事を確認し、基本モデルを作製同時に評価設備（特性信頼性確認）の製作 2.特性達成に重要な最適磁性材料の探索 3.安価生産の肝となる構造材料の選定・製作技術の確立
Development of in-wheel magnetic-geared motor for walking support machines

NAKAMURA Kenji

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (B)

Institution: Tohoku University

2016/04/01 - 2019/03/31

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This study discussed efficiency improvement and feasibility study of in-wheel magnetic-geared motor for walking support machines. As a result, both torque increasing and loss decreasing were achieved by employing open-slot structure, low-loss core material, and interior permanent magnet rotor. Based on the results, the magnetic-geared motor was prototyped and tested. The test results demonstrated that desired torque can be obtained, and the maximum efficiency reached to 84.7%. Furthermore, it was proved that the prototype motor can be applied to walking support machines.
Development of a novel three-dimensional three-phase variable inductor and application to reactive power compensator in electric power systems

Nakamura Kenji

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Challenging Exploratory Research

Institution: Tohoku University

2016/04/01 - 2018/03/31

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A variable inductor can be applied as a reactive power compensator in electric power systems, and has desirable features such as a simple and robust structure, low cost. In a previous work, a concentric-winding type three-phase variable inductor with a two-dimensional structure was proposed. To further improved the performance, novel concentric-winding type three-phase variable inductor with a three-dimensional structure was proposed in this research. As a result, it was demonstrated that the leakage flux of the proposed three-dimensional variable inductor is reduced by more than 30%. Furthermore, a 6.6 kV-100 kVA three-dimensional variable inductor was designed and compared to its two-dimensional counterpart. It was proved that eddy current loss, which is induced within an oil-immersed self-cooled tank because of leakage flux, can be reduced to one-third of that of the two-dimensional variable inductor.
Development of Flux-Modulated type Magnetic-Geared Motor and Generator

Nakamura Kenji

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Challenging Exploratory Research

Institution: Tohoku University

2014/04/01 - 2016/03/31

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In this study, we conducted a feasibility study of a magnetic-geared motor and generator by both numerical analysis and experiment. First, we compared an axial-gap-type magnetic-geared motor to a radial-gap one. As a result, the radial-gap one is superior to the axial-gap one even if the machine structure becomes flat, because the radial-gap type can be utilize a dead-space inside the gear part, thus the space utility factor was improved in comparison with the axial-gap one. Next, prototype tests of the radial-gap-type magnetic-geared motor were conducted. As a result, torque of the prototype machine exceeded a required characteristic.
Study on Axial Gap Switched Reluctance Motor for Electric Vehicle Application

Ichinokura Osamu, NAKAMURA Kenji, GOTO Hiroki

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (B)

Institution: Tohoku University

2013/04/01 - 2016/03/31

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Rare earth materials such as neodymium and dysprosium are used in the motors for electric vehicles, that reduction is required for resource reasons. Switched reluctance(SR) motor is expected as rare earth material free motor. But it has less efficiency and output compared with conventional motor. Then, we focused on axial gap structure which magnetic flux flows to axial direction, and we applied the axial gap structure to SR motor. As a result, better performance of the proposed axial gap SR motor than that of is achieved than that of traditional rare earth motor. In addition, driving tests using small electric cars with two axial gap SR motors was done successfully.
Development of a magnetic-geared generator for a small-scale wind-turbine

NAKAMURA Kenji

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (B)

Institution: Tohoku University

2012/04/01 - 2015/03/31

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First, support materials and methods of pole-pieces of a flux-modulated type magnetic gear were investigated and shape and dimensions of the pole-pieces were optimized by a finite element method (FEM). As a result, torque of the magnetic gear was improved by over 40% and efficiency was reached to over 99%, which is better than conventional mechanical gears. Next, a magnetic-geared motor/generator, which is composed of a permanent magnet machine and a magnetic gear, was designed by FEM, and prototyped. As a result, the prototype machine demonstrated a good performance as designed. Next, a 1 kW small-scale wind-turbine generator is installed and a measurement system of voltage, current, and wind verbosity for a long-term was constructed.
Development of a large torque motor using a polar anisotropic Sm-Fe-N bonded magnet

NAKAMURA Kenji

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Challenging Exploratory Research

Institution: Tohoku University

2012/04/01 - 2014/03/31

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In 2012, we examined the optimum configuration of an outer rotor type surface permanent magnet (SPM) motor using a polar anisotropic Sm-Fe-N bonded magnet by using finite element method (FEM). As a result, it was clear that the proposed SPM motor exhibits the same torque as a conventional Nd-Fe-B sintered magnet motor when the number of pole-pairs is increased up to 40 while keeping a ratio of width and length per one magnet 2:1. In 2013, to further increase the torque, we investigated an interior permanent magnet (IPM) structure. As a result, it was clear that the proposed IPM motor demonstrates 1.2 times larger torque than a conventional Nd-Fe-B sintered magnet motor, when the IPM rotor has two-layer flux-barrier structure which has small amount of Nd-Fe-B sintered magnet in the first layer, while the large amount of ferrite magnet (it has less flux density than Sm-Fe-N bonded magnet) in the second layer.
IT融合による次世代自動車産業創出のための実証・評価及び研究開発拠点形成事業 Competitive

Offer Organization: 経済産業省

System: IT融合による新産業創出のための研究開発事業（産学官IT融合コンソーシアム拠点の整備）

Institution: 東北大学

2012/03 - 2013/03
A Study about Drive Circuit Integrated type In-Wheel SR Motor for Large-Size Trailer Vehicles

ICHINOKURA Osamu, NAKAMURA Kenji, GOTO Hiroki

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (A)

Institution: Tohoku University

2010 - 2012

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In the study, for the purpose of improvement of driving stability and fuel consumption of large trailer vehicles, we developed drive circuit integrated type in-wheel SR motors. First, an optimal design of the motor and control method are decided by simulations. Next, the designed motor and circuit are manufactured and tested. Finally, the running tests were succeeded. It was found usefulness of proposed drive circuit integrated type in-wheel SR motor.
鉄－窒素系化合物を活用した新規永久磁石材料の開発 Competitive

Offer Organization: (独)新エネルギー・産業技術総合開発機構(NEDO)

System: 希少金属代替材料開発プロジェクト（Nd-Fe-B系磁石を代替する新規永久磁石の開発）

Institution: 東北大学

2010/03 - 2011/03
Development of super-multipolar permanent magnet reluctance generator and its application to small-scale wind-turbine and hydroelectric power generation

NAKAMURA Kenji

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Young Scientists (A)

Institution: Tohoku University

2010 - 2011

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Both a super-multipolar permanent magnet reluctance generator (PMRG)and a PMRG with auxiliary windings and magnets are investigated respectively. In the super-multipolar PMRG, to apply for a small-scale wind-turbine generation, a 96/64-pole PMRG which can be driven without gearbox was designed. The diameter is 600 mm, and axial length is 52 mm. The rated power is 1. 0 kW (100 rpm). In the PMRG with auxiliary windings and magnets, it is clear that the output power can be controlled linearly by the auxiliary winding current.
Development of dual-rotor-type permanent magnet reluctance generator adapting for car

NAKAMURA Kenji

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Challenging Exploratory Research

Institution: Tohoku University

2010 - 2011

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In 2010, characteristics of a dual-rotor-type permanent magnet reluctance generator (PMRG)are examined by using finite element method (FEM). As a result, cogging torque is reduced to half since harmonic contents of torque of both rotors are canceled when inside and outside rotors have differential phase angle of 180 electrical degrees each other. However, output power was not improved. In 2011, to establish the compact and high power generation system comprising a combination of the PMRG and a magnetic gear, the high performance magnetic gear is designed. As a results, it was clear that the magnetic gear used a polar-anisotropic bonded magnet has desirable features.
小型風力発電用超多極永久磁石リラクタンスジェネレータの開発 Competitive

Offer Organization: 独立行政法人科学技術振興機構

System: 重点地域研究開発推進プログラム

Category: シーズ発掘試験

Institution: 東北大学

2009/04 - 2010/03

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小型風力発電では、数ｍ/ｓ程度の低風速が主な動作領域であり、発電機の回転数にすると数十～数百ｒｐｍと極めて低速になる。このような低速でも高効率な発電をする小型軽量でトルクリプルが少なくかつ低コストな発電機を実現する。永久磁石リラクタンスジェネレータ（ＰＭＲＧ）は、構造が簡素で、多極化も容易であるため、小型風力用発電機として有望である。本研究では、低風速でも高効率な発電が期待できる超多極ＰＭＲＧの開発と、極形状の工夫によるトルクリプルの低減を目標とする。
インホイール電気自動車用磁気ギア内臓モータの開発

一ノ倉理, 中村健二

Offer Organization: 日本学術振興会

System: 科学研究費助成事業

Category: 挑戦的萌芽研究

Institution: 東北大学

2009 - 2010

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昨年度、アウターロータ型の表面磁石モータを比較対象として、これに磁気ギアを内蔵したモータについて性能の評価を行ったところ、ギア比を2:33とすることで、従来の表面磁石モータに対して約2倍のトルクが得られることが明らかになった。ただし、単純にギア比で評価すると、トルクは16.5倍となることから、予想よりも得られるトルクは小さいことがわかった。本年度は、まずこの原因を突き止めるため、有限要素法(FEM)の電磁界解析により、ギャップの磁束分布を詳しく調べた。その結果、磁気ギアにおいて、トルクに寄与する磁束成分は基本波では無く、高調波成分となること、そのため、振幅は基本波成分よりも著しく小さくなることが明らかになった。今後、高調波磁束を大きくできるギア構成について検討する必要がある。次いで、永久磁石型磁気ギア単体の評価を行った。磁気ギアの性能に大きく寄与する、磁石長、ギャップ長、ポールピース長、極数の組み合わせについて、FEMを用いて種々設計パラメータを変更して比較を行ったところ、特に極数の組み合わせ(ギア比)を変えると、同体格であっても最大伝達トルクが大きく変化することが明らかになった。この結果をふまえて、今後はトルク密度を最大にする設計法の確立につなげる予定である。また上記の考察に基づき、ギア比約10:1の磁気ギアを試作して実験を行ったところ、ほぼ設計通りのトルクが伝達できることを確かめた。今後は、伝達効率の評価など、さらに詳細な検討を進める予定である。
新エネルギー用マイクロ発電システムの開発 Competitive

Offer Organization: 福島県ハイテクプラザ

System: 公募型新事業創出プロジェクト研究事業

Institution: 東北大学

2007/06 - 2009/02
Development of the three-phase-laminated-core variable inductor and its application to the voltage stabilizer in electric power systems

NAKAMURA Kenji

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Young Scientists (B)

Institution: Tohoku University

2007 - 2008
永久磁石アシスト式大トルク・高効率スイッチトリラクタンスモータの開発

一ノ倉理, 中村健二

Offer Organization: 日本学術振興会

System: 科学研究費助成事業

Category: 萌芽研究

Institution: 東北大学

2007 - 2008

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平成20年度においては、省・脱レアアースマグネットに対する社会の要求が急速に強まって来たことを踏まえて、昨年度開発した永久磁石アシスト式スイッチトリラクタンス(SR)モータの磁石レス化に取り組んだ。 SRモータの特性は、材料の磁気特性に大きく左右される。そこで、通常の無方向性ケイ素鋼板と比べて、2〜3割以上飽和磁束密度の高いパーメンダ(Fe-Co合金)に着目し、その適用可能性について有限要素法(FEM)を用いて検討を行った。その結果、同体格、同寸法のモータで比較すると、従来のSRモータに比べて、定格トルクが40%程度大きくなることが明らかになった。また、鉄損は約半減した。しかしながら一方で、軽負荷領域での優位性は認められなかった。この原因は、軽負荷領域では、SRモータの動作点は磁気特性の線形領域にあるため、性能が巻数とギャップ長で決まってしまうためである。すなわち、パーメンダを利用したメリットが最大限活かされていなかった。そこで、パーメンダの高い飽和磁束密度に着目し、従来よりも固定子極幅やヨーク幅を狭くし、その分巻数を増やす設計をしたところ、軽負荷領域でも2倍以上のトルクの向上が認められた。また、効率では全運転範囲において向上が認められ、最大で約5%の効率改善を実現した。なお、上記のパーメンダ適用SRモータの設計には、機器パラメータが性能に及ぼす影響を,統計的かつ効率的に評価できる設計手法である実験計画法を用いることで、モータ設計の効率化を図った。
Study on local energy utilization system using a permanent magnet type multi-polar RG

ICHINOKURA Osamu, NAKAMURA Kenji, GOTO Hiroki

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (B)

Institution: Tohoku University

2007 - 2008
分散型電源の系統連系点における電圧安定化を実現する三相一体構造可変インダクタの開発 Competitive

Offer Organization: (財)カシオ科学技術振興財団

System: 研究助成

Institution: 東北大学

2007/01 - 2007/12
電気自動車用インホイール多極スイッチトリラクタンスモータの開発 Competitive

Offer Organization: (財)服部報公会

System: 工学研究奨励援助

Institution: 東北大学

2004/09 - 2005/08
Study on Outer Rotor Type Multipolar SR Motor and its Application to Electric Vehicle

ICHINOKURA Osamu, HI-JIAO Guo, NAKAMURA Kenji

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (B)

Institution: Tohoku University

2004 - 2005

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Switched reluctance motor (SR motor) exhibits desirable features including high reliability, good efficiency and low cost because the SR motor has simple and solid structure without permanent magnets and rotor windings. Unfortunately, the SR motor has not been put into practical applications widely because of its large torque ripple and acoustic noise. However, recent motor technology, which includes an optimum design based on FEM and instantaneous current control using DSP or FPGA, overcomes gradually the defects of the SR motor. Some products such as fuel pump, washing machine and vacuum cleaner have been already presented in the practical applications of SR motor. In this research, we proposed an outer rotor type multi-polar SR motor as a new attempt, and developed a multi-polar SR motor to an small electric vehicle for two years. The obtained results are as follows : The results obtained in the year 2004 1. Establishment of dynamic analysis method for SR motor. 2. Design of the outer rotor type multi-polar SR motor for electric vehicle. 3. Manufacturing of the outer rotor type multi-polar SR motor for electric vehicle. 4. Manufacturing of the driving circuit and controller for the outer rotor type multi-polar SR motor. The results obtained in the year 2005 1. Manufacturing the electric vehicle with the developed multi-polar SR motor, the driving circuit and controller. 2. Improvement of the driving circuit and controller for the purpose of reliable operation. 3. Driving experiments. 4. Proposal of new control methods of the SR motor for improvement of the performance of the electric vehicle. 5. Establishment of the optimum design method of the SR motor. To conclude, we developed a new outer rotor type multi-polar SR motor and realized a direct driving electric vehicle using the developed SR motor in this research. The electric vehicle has good performance. Then the original target of this research has been accomplished.
直交磁心型移相器の開発と電力潮流制御への応用に関する研究

中村健二

Offer Organization: 日本学術振興会

System: 科学研究費助成事業

Category: 若手研究(B)

Institution: 東北大学

2003 - 2004

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平成16年度においては,まず前年度のシミュレーションによる検討により,動作確認を行った直交磁心型移相器システムの設計と製作を行った。1.5k VA級の直交磁心型三相可変インダクタについては,昨年度既に製作を行っている。本年度は,移相器システムを構成する上で重要な装置である,母線電圧に対して90度位相差を有する電圧を得るための調整変圧器と,機器設置点の線路電圧の位相を制御する直列変圧器の設計・製作を行った。設計製作を行った上記の直交磁心型可変インダクタ,変圧器,並びに制御用直流電源,三相交流電源を用いて直交磁心型移相器システムの構築を行った。次いで,構築した実験システムを用いて電力潮流制御実験を行った。動作原理上,潮流の向きを制御すること不可能であるが,本装置は潮流の大きさを線形かつ連続的に制御可能であることが明らかになった。なお,可制御範囲は50W〜800Wで有り,直交磁心型三相可変インダクタの容量1.5k VAの半分程度であった。今後は,システムの最適化について更に検討を進める必要がある。出力電流波形についてもほぼ正弦波の出力が得られた。今回実験を行った範囲では,全制御範囲で実効的な電流歪み率が3%以下になり,高調波フィルタ無しで系統との連系が可能であることが示された。以上により,直交磁心型移相器の開発と電力潮流制御に関する研究は,ほぼ所期の目的を達成できたものと考えられる。
直交磁心を用いた直列補償型潮流制御器に関する研究

中村健二

Offer Organization: 日本学術振興会

System: 科学研究費助成事業

Category: 若手研究(B)

Institution: 東北大学

2001 - 2002

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平成14年度においては,まず直列補償型潮流制御器の試作を行った。本研究で提案する直列補償型潮流制御器は直交磁心型可変インダクタとコンデンサを並列に接続して構成される。これを系統に直列に挿入し,直交磁心の実効的なインダクタンスを調整すれば,系統の線路インピーダンスが変化し,系統を流れる電力の大きさと向きを制御することができる。上記のシステムを構成し,実験を行ったところ直交磁心の実効的なインダクタンスを調整することで,容易に電力の大きさと向きを制御可能であることが確かめられた。一方,一般に直交磁心型三相可変インダクタを系統に適用する際には,非線形磁気特性に起因する第3調波電流を還流させるため主巻線は三相デルタ結線されるが,この潮流制御器では直交磁心の主巻線は系統に直列に接続されるため,三相デルタ結線することができず,そのため第3調波電流が系統に流れ込んでしまう問題が生じる。これに対して,筆者は直交磁心の制御電源用巻線に用いられている三次巻線を三相デルタ結線することで,第3調波電流の低減が可能であるか検討を行った。その結果,低減率は三次巻線の巻線抵抗と系統の線路のインピーダンスの比で決まること,一般に巻線抵抗は線路インピーダンスに比べて十分小さいことから第3調波電流は実用上問題の無いレベルまで低減可能であることを明らかにした。また,三次巻線に吸収された第3調波電流は整流され,制御巻線の直流励磁用電流として用いられるため,効率の低下もほとんど無いと考えられる。上記の考えに基づいた潮流制御器を構成し実験を行ったところ,出力電流波形がほぼ正弦波で,良好な制御特性を有することが明らかになった。以上により,直交磁心を用いた潮流制御器に関する研究はほぼ所期の目的を達成できたものと考えられる。

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Social Activities 38

寺子屋ＢＭ塾

磁気応用（回転機）/（静止器）/（解析技術）全3回

2021/05/28 - 2021/07/16
JMAG ユーザー会議 2008

2008/12/10 - 2008/12/11
第43回モータ技術シンポジウム

軟磁性材料から見たモータ特性改善への取り組み

2023/03/09 -
The 4th International Symposium on AI and Electronics

Contactless Magnetic Gears and Magnetic-Geared Motors

2023/02/13 -
第42回モータ技術シンポジウム

磁気ギヤ・磁気ギヤードモータの最新の研究紹介

2022/08/05 -
第30回磁気応用技術シンポジウム

磁気ヒステリシスを考慮した磁気回路法の基礎と応用

2022/07/20 -
第42回モータ技術シンポジウム

NANOMET積層コアを用いて製作したモータの実機評価

2022/07/20 -
第29回磁気応用技術シンポジウム

先端電磁界解析技術の現状と応用事例

2021/06/14 -
マグネティックスによるパワーエレクトロニクスの革新と協創

磁気回路法に基づくヒステリシスモデリング技術

2021/01/20 -
2020BM シンポジウム

磁性材料から見たモータの研究開発事例

2020/12/04 -
東北大学レアメタル・グリーンイノベーション研究開発センター第６回フォーラム

次世代移動体用インホイール磁気ギヤードモータの開発

2020/11/05 -
第38次モータ技術フォーラム

磁気回路法解析の基礎と応用事例

2019/09/24 -
第７回MaSC技術交流会

磁性材料から見たモータ開発事例紹介

2019/07/25 -
第27回磁気応用シンポジウム（Techno Frontier 2019）

磁気回路法による最新の損失算定技術

2019/04/17 -
産学交流の日

次世代移動体用磁気ギヤードモータの開発

2018/11/05 -
あきた産学官金総結集新産業創出事業

小水力・マイクロ水力発電用レアアースフリー高出力・高効率発電機

2018/10/12 -
第121回寺子屋仙台

非接触磁気ギヤの基礎と磁気ギヤードモータへの展開

2018/05/15 -
第26回磁気応用シンポジウム（Techno Frontier 2018）

磁気回路法による損失解析技術

2018/04/19 -
第37回モータ技術シンポジウム（Techno Frontier 2017）

2017/04/20 -
福島成蹊高等学校「理科講演会」

2016/05/27 -
第24回磁気応用技術シンポジウム（Techno Frontier 2016）

2016/04/20 -
長野県屋代高等学校進路系統別講演会「屋代ミニ大学」

2015/09/12 -
第35回モータ技術シンポジウム（Techno Frontier 2015）

2015/05/21 -
IDAJ CAE Solution Conference 2014

2014/11/13 -
長野県屋代高等学校進路系統別講演会「屋代ミニ大学」

2014/09/13 -
第22回磁気応用技術シンポジウム（Techno Frontier 2014）

2014/07/23 -
日本学術振興会第173委員会

2014/01/31 -
長野県屋代高等学校進路系統別講演会「屋代ミニ大学」

2013/09/14 -
長野県屋代高等学校東北サイエンス交流会

2013/08/02 -
長野県屋代高等学校進路系統別講演会「屋代ミニ大学」

2012/09/15 -
宮城県立泉高等学校「大学出張講義」

2012/06/27 -
第18回磁気応用技術シンポジウム（Techno Frontier 2010）

2010/07/22 -
エネルギー・環境技術の未来～低炭素社会へ向けた取り組みのために～

2009/12/04 -
第17回磁気応用技術シンポジウム（Techno Frontier 2009）

2009/04/15 -
エレクトロメカニカルパワエレセミナー

2008/07/28 -
第15回磁気応用技術シンポジウム（Techno Frontier 2007）

2007/04/19 -
JMAG ユーザー会議 2006

2006/11/02 -
EDA Solution Conference 2005

2005/12/14 -

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Media Coverage 4

東北大とTDK、「TDK×東北大学再生可能エネルギー変換デバイス・材料開発共創研究所」を設置

日本経済新聞

2022/10

Type: Newspaper, magazine
次世代車両向け駆動モータ用回転角度センサーを開発

日本経済新聞

2018/12

Type: Newspaper, magazine

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東北大学大学院工学研究科の中村健二教授と株式会社松尾製作所らの研究グループは、次世代車両向け駆動モータ用回転角度センサの開発を行いました。電磁鋼板一枚を曲げて薄肉形状にし、磁場の経路を成立させることで、材料の使用量の低減、重量、コストを削減させることに成功しました。本研究成果を車両に適用することで、車両の軽量化、及びそれに伴うエネルギー効率の向上に貢献することが期待されます。
レアアース不要のSRモータ磁石並みトルク密度

2012/12/05

Type: Newspaper, magazine
磁気回路法でモータ解析

日刊工業新聞

2009/02/16

Type: Newspaper, magazine

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東北大学の一ノ倉理教授、中村健二准教授らは、磁気回路法を基に新たなモーター解析技術を開発した。独自の発想で、鉄心の非線形磁気特性や磁石の着磁特性を考慮して、モーターの動的磁気回路モデルを構築した。汎用回路シミュレーター「ＳＰＩＣＥ」などを利用し、駆動回路や制御を含めたモーターシステムの総合的な動作特性を、従来の解析手法より短時間で高精度に算定できる。モーター機器の設計開発のコストや期間の低減につながる。

Academic Activities 20

ICEMS 2024 実行委員会委員, 論文委員会副委員長

2024/11/26 - 2024/11/29

Activity type: Academic society, research group, etc.
INTERMAG 2024 Program Committee Member

2024/05/06 - 2024/05/10

Activity type: Academic society, research group, etc.
INTERMAG 2023 Program Committee Co-Chair

2023/05/15 - 2023/05/19

Activity type: Academic society, research group, etc.
IPEC 2022 Track Chair

2022/05/15 - 2022/05/19

Activity type: Academic society, research group, etc.
15th Joint MMM/Intermag Conference Editor / ProCom Member

2022/01/10 - 2022/01/14

Activity type: Academic society, research group, etc.
INTERMAG 2021 Editor / ProCom Member

2021/04/26 - 2021/04/30

Activity type: Academic society, research group, etc.
ICEMS 2020 組織委員会委員, ゲストエディタ

2020/11/24 - 2020/11/27

Activity type: Academic society, research group, etc.
IPEC 2018 論文委員会委員

2018/05/20 - 2018/05/24

Activity type: Academic society, research group, etc.
ICEMS 2016 実行委員会委員

2016/11/13 - 2016/11/16

Activity type: Academic society, research group, etc.
電気学会全国大会現地実行委員会幹事

2016/03/16 - 2016/03/18

Activity type: Academic society, research group, etc.
13th Joint MMM/Intermag Conference ProCom Member

2016/01/11 - 2016/01/15

Activity type: Academic society, research group, etc.
INTERMAG 2015 ProCom Member

2015/05/11 - 2015/05/15

Activity type: Academic society, research group, etc.
IPEC 2014 論文委員会委員

2014/05/18 - 2014/05/21

Activity type: Academic society, research group, etc.
INTERMAG 2014 ProCom Member

2014/05/04 - 2014/05/08

Activity type: Academic society, research group, etc.
12th Joint MMM/Intermag Conference ProCom Member

2013/01/14 - 2013/01/18

Activity type: Academic society, research group, etc.
ICEMS 2012 論文委員会委員

2012/10/21 - 2012/10/24

Activity type: Academic society, research group, etc.
電気関係学会東北支部連合大会実行委員会幹事

2011/08/25 - 2011/08/26

Activity type: Academic society, research group, etc.
ISAMMA 2010 ProCom Member

2010/07/12 - 2010/07/16

Activity type: Academic society, research group, etc.
ICEMS 2009 論文委員会委員

2009/11/15 - 2009/11/18

Activity type: Academic society, research group, etc.
第32回日本磁気学会学術講演会実行委員会委員

2008/09/12 - 2008/09/15

Activity type: Academic society, research group, etc.

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