| FUJIWARA Koji |  |
| Faculty of Science and Engineering Department of Electrical Engineering | |
| Professor |
Last Updated :2024/04/25
Researcher Profile and Settings
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Research Areas
- Manufacturing technology (mechanical, electrical/electronic, chemical engineering) / Electrical power engineering
Education
- Okayama University, Graduate School of Engineering, Department of Electrical Engineering, 1982/04 - 1984/03
- Okayama University, Faculty of Engineering, Department of Electrical Engineering, 1978/04 - 1982/03
Published Papers
- Stray Loss Evaluation of Power Transformers Using Simplified Air-Core Model With Tank and Frame
Botao Liu; Yasuhito Takahashi; Koji Fujiwara; Satoshi Imamori
IEEE Transactions on Magnetics, 59(11), 01 Nov. 2023, Scientific journal - Model Order Reduction of Cage Induction Motor With Skewed Rotor Slots Using Multiport Cauer Ladder Network Method
Yasuhito Takahashi; Koji Fujiwara; Kengo Sugahara; Tetsuji Matsuo
IEEE Transactions on Magnetics, Institute of Electrical and Electronics Engineers (IEEE), 59(5) 1 - 4, May 2023, Scientific journal - Parallel-in-Space-and-Time Finite-Element Method for Time-Periodic Magnetic Field Problems with Hysteresis
Yasuhito Takahashi; Koji Fujiwara; Takeshi Iwashita
IEEE Transactions on Magnetics, 2023, Scientific journal - Modelling of <i>I-V</i> Characteristics for Crystalline Silicon Photovoltaic Modules based on a Simplified Equivalent Circuit and a Temperature Correction
Yuki Ohnishi; Yasuhito Takahashi; Koji Fujiwara; Kazuyuki Hidaka; Hiroshi Morita
IEEJ Transactions on Power and Energy, Institute of Electrical Engineers of Japan (IEE Japan), 142(9) 461 - 471, 01 Sep. 2022, Scientific journal - Parallel-in-space-and-time finite-element analysis of electric machines using time step overlapping in a massively parallel computing environment
Yasuhito Takahashi; Koji Fujiwara; Takeshi Iwashita
COMPEL-THE INTERNATIONAL JOURNAL FOR COMPUTATION AND MATHEMATICS IN ELECTRICAL AND ELECTRONIC ENGINEERING, EMERALD GROUP PUBLISHING LTD, Jul. 2022, Scientific journal - Enhanced Behavioral Modeling for Permanent Magnet Synchronous Motors Fed by Pulse-width Modulation Inverters Considering Harmonic Losses
Shotaro Tsujikawa; Yasuhito Takahashi; Koji Fujiwara
IEEJ Transactions on Industry Applications, Institute of Electrical Engineers of Japan (IEE Japan), 142(4) 299 - 308, 01 Apr. 2022, Scientific journal - Modelling of Magnetic Anisotropy Due to Compression Molding of Soft Magnetic Composite for Inductance Calculation
Yanhui Gao; Yuuji Gotoh; Kyoya Hamada; Shun Araki; Kazuhiro Muramatsu; Yukiha Takeuchi; Yasuhito Takahashi; Koji Fujiwara; Tetsuya Ogawa; Chio Ishihara; Kohei Aiba; Seira Otsuka
IEEE Transactions on Magnetics, 2022, Scientific journal - Comparison of Parallel-in-Space-and-Time Finite-Element Methods for Magnetic Field Analysis of Electric Machines
Yasuhito Takahashi; Koji Fujiwara; Takeshi Iwashita; Hiroshi Nakashima
IEEE TRANSACTIONS ON MAGNETICS, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 57(6), Jun. 2021, Scientific journal - The international round robin test of magnetostriction measurement of grain-oriented electrical steel by means of a single sheet tester and an optical sensor
Jumpei Kobori; Yasuhito Takahashi; Koji Fujiwara
Journal of Magnetism and Magnetic Materials, Elsevier BV, 513 166541 - 166541, Nov. 2020, Scientific journal - A measurement method of minor hysteresis loss of electrical steel sheet by means of a single sheet tester
Hidefumi Okama; Yasuhito Takahashi; Koji Fujiwara
Journal of Magnetism and Magnetic Materials, 505, 01 Jul. 2020, Scientific journal - Pinning field representation using play hysterons for stress-dependent domain-structure model
Tetsuji Matsuo; Yasuhito Takahashi; Koji Fujiwara
Journal of Magnetism and Magnetic Materials, 499, Apr. 2020, Scientific journal - Behavioral modeling of permanent magnet synchronous motor fed by PWM inverters considering iron losses due to carrier harmonics
Yusaku Shutta; Yasuhito Takahashi; Koji Fujiwara
Electrical Engineering in Japan (English translation of Denki Gakkai Ronbunshi), 2020, Scientific journal - Iron Loss Estimation for IPM Motors based on Eddy Current Loss Correction Factor Considering Plastic Deformation by Punching
Takuya Yoshioka; Yasuhito Takahashi; Koji Fujiwara
IEEJ Transactions on Power and Energy, Institute of Electrical Engineers of Japan (IEE Japan), 139(12) 767 - 775, 01 Dec. 2019, Scientific journal - Finite-element Analysis of Soft Magnetic Composites using Dynamic Hysteresis Modeling based on Cauer Circuit Representation of Eddy-current Fields
Naoya Watanabe; Yasuhito Takahashi; Koji Fujiwara
IEEJ Transactions on Power and Energy, Institute of Electrical Engineers of Japan (IEE Japan), 139(11) 643 - 649, 01 Nov. 2019, Scientific journal - Behavioral Modeling of Permanent Magnet Synchronous Motor Fed by PWM Inverters Considering Iron Losses Due to Carrier Harmonics
Yusaku Shutta; Yasuhito Takahashi; Koji Fujiwara
IEEJ Transactions on Industry Applications, Institute of Electrical Engineers of Japan (IEE Japan), 139(11) 939 - 946, 01 Nov. 2019, Scientific journal - Parallel finite-element method using domain decomposition and Parareal for transient motor starting analysis
Takahashi Yasuhito; Fujiwara Koji; Iwashita Takeshi; Nakashima Hiroshi
COMPEL-THE INTERNATIONAL JOURNAL FOR COMPUTATION AND MATHEMATICS IN ELECTRICAL AND ELECTRONIC ENGINEERING, 38(5) 1507 - 1520, 02 Sep. 2019 - Finite-element analysis of turbine generator using homogenization method taking account of magnetic anisotropy
Ryoko Minehisa; Yasuhito Takahashi; Koji Fujiwara; Norio Takahashi; Masafumi Fujita; Kazuma Tsujikawa; Ken Nagakura
COMPEL - The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, Emerald, 38(5) 1614 - 1626, Jul. 2019, Scientific journal - Parallel TP-EEC Method based on Polyphase Time-Periodic Condition for Magnetic Field Analysis of Induction Motors
Yasuhito Takahashi; Koji Fujiwara; Tadashi Tokumasu; Takeshi Iwashita; Hiroshi Nakashima
Proc. Intl. Conf. Computation on Electromagnetic Fields, Jul. 2019, International conference proceedings - Iron Loss Estimation Method for Silicon Steel Sheet Taking Account of DC-Biased Conditions
Takuya Yoshioka; Takuya Tsuge; Yasuhito Takahashi; Koji Fujiwara
IEEE Transactions on Magnetics, 55(6), Jun. 2019, Scientific journal - Iron Loss Analysis of Interior Permanent Magnet Synchronous Motors Using Dynamic Hysteresis Model Represented by Cauer Circuit
Naoki Minowa; Yasuhito Takahashi; Koji Fujiwara
IEEE Transactions on Magnetics, 55(6), Jun. 2019, Scientific journal - Frozen Permeability Method for Magnetic Field Analysis of Permanent Magnet Motors Considering Hysteretic Property
Daisuke Shuto; Yasuhito Takahashi; Koji Fujiwara
IEEE Transactions on Magnetics, 55(6), Jun. 2019, Scientific journal - Parallel Finite-Element Method Based on Space-Time Domain Decomposition for Magnetic Field Analysis of Electric Machines
Yasuhito Takahashi; Koji Fujiwara; Takeshi Iwashita; Hiroshi Nakashima
IEEE Trans. Magnetics, 55 1 - 4, Feb. 2019, Scientific journal - Dynamic hysteresis modeling of silicon steel sheet considering excess eddy-current loss
Minowa Naoki; Takahashi Yasuhito; Fujiwara Koji; Ahagon Akira; Matsuo Tetsuji
INTERNATIONAL JOURNAL OF APPLIED ELECTROMAGNETICS AND MECHANICS, 59(1) 217 - 226, 2019 - Efficient multiscale magnetic-domain analysis of iron-core material under mechanical stress
Atsushi Nishikubo; Shumpei Ito; Takeshi Mifune; Tetsuji Matsuo; Chikara Kaido; Yasuhito Takahashi; Koji Fujiwara
AIP Advances, American Institute of Physics Inc., 8(5), 01 May 2018, Scientific journal - Simulation of the stress dependence of hysteresis loss using an energy-based domain model
Shumpei Ito; Takeshi Mifune; Tetsuji Matsuo; Chikara Kaido; Yasuhito Takahashi; Koji Fujiwara
AIP Advances, American Institute of Physics Inc., 8(4), 01 Apr. 2018, Scientific journal - New Type of Second-Order Tetrahedral Edge Elements by Reducing Edge Variables for Quasi-Static Field Analysis
Akira Ahagon; Akihisa Kameari; Hassan Ebrahimi; Koji Fujiwara; Yasuhito Takahashi
IEEE Transactions on Magnetics, Institute of Electrical and Electronics Engineers Inc., 54(3), 01 Mar. 2018, Scientific journal - Input and Output Power in Finite-Element Analysis of Electric Machines Taking Account of Hysteretic Property
Junji Kitao; Yasuhito Takahashi; Koji Fujiwara; Akira Ahagon; Tetsuji Matsuo; Akihiro Daikoku
IEEE Transactions on Magnetics, Institute of Electrical and Electronics Engineers Inc., 54(3), 01 Mar. 2018, Scientific journal - Domain structure model including pinning effect based on the statistical density function
Shumpei Ito; Tetsuji Matsuo; Yasuhito Takahashi; Takeshi Mifune; Chikara Kaido; Koji Fujiwara
IEEJ Transactions on Fundamentals and Materials, Institute of Electrical Engineers of Japan, 138(3) 71 - 75, 2018, Scientific journal - Study of computation method of iron loss considering magnetic isotropic by processing residual stress
Satoshi Doi; Tetsuya Aoki; Keiichi Okazaki; Yasuhito Takahashi; Koji Fujiwara
IEEJ Transactions on Power and Energy, Institute of Electrical Engineers of Japan, 138(1) 36 - 44, 2018, Scientific journal - Hysteresis Loss Analysis of Laminated Iron Core by Using Homogenization Method Taking Account of Hysteretic Property
Junji Kitao; Yasuhito Takahashi; Koji Fujiwara; Akira Ahagon; Tetsuji Matsuo; Akihiro Daikoku
IEEE TRANSACTIONS ON MAGNETICS, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 53(6) 7203104 - 4, Jun. 2017, Scientific journal - Steady-State Analysis of Hysteretic Magnetic Field Problems Using a Parallel Time-Periodic Explicit-Error Correction Method
Yasuhito Takahashi; Junji Kitao; Koji Fujiwara; Akira Ahagon; Tetsuji Matsuo; Takeshi Iwashita; Hiroshi Nakashima
IEEE TRANSACTIONS ON MAGNETICS, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 53(6), Jun. 2017, Scientific journal - Basic investigation of deterioration on magnetic properties of laminated iron core after welding process
Kohei Kawaguchi; Yasuhito Takahashi; Koji Fujiwara; Makoto Matsushita; Norio Takahashi; Tadashi Tokumasu
INTERNATIONAL JOURNAL OF APPLIED ELECTROMAGNETICS AND MECHANICS, IOS PRESS, 55 S169 - S176, 2017, Scientific journal - Investigation of a measurement method of 2-D magnetic properties by means of 1-D single sheet tester
Yusuke Kimura; Yasuhito Takahashi; Koji Fujiwara
INTERNATIONAL JOURNAL OF APPLIED ELECTROMAGNETICS AND MECHANICS, IOS PRESS, 55 S97 - S104, 2017, Scientific journal - Magnetomechanically coupled domain model of electrical steel sheet for electric machine core
Shumpei Ito; Takeshi Mifune; Tetsuji Matsuo; Chikara Kaido; Yasuhito Takahashi; Koji Fujiwara
IEEJ Transactions on Power and Energy, Institute of Electrical Engineers of Japan, 137(12) 736 - 741, 2017, Scientific journal - A study on multiply connected domain processing methods in magnetostatic field analysis by boundary integral equations
Kengo Ryu; Shinji Wakao; Yasuhito Takahashi; Kazuhisa Ishibashi; Koji Fujiwara
IEEJ Transactions on Power and Energy, Institute of Electrical Engineers of Japan, 137(2) 132 - 137, 2017, Scientific journal - 等方性ベクトルプレイモデルにおける回転ヒステリシス損の算出精度向上に関する検討
北尾 純士; ?橋 康人; 藤原 耕二; 阿波根 明; 松尾 哲司; 大穀 晃裕
電気学会論文誌． Ｂ, 137(3) 216 - 222, Jan. 2017, Scientific journal - Study on Standard Measurement Method of Magnetic Property of Fe-Based Amorphous Strip-Round Robin Test Results
Ryu Watakabe; Masaya Tanaka; Yasuhito Takahashi; Koji Fujiwara; Yoshiyuki Ishihara; Daichi Azuma
IEEE TRANSACTIONS ON MAGNETICS, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 52(5) 6000204 , May 2016, Scientific journal - Magnetostatic Shield Analysis by Double-Layer Charge Formulation Using Difference Field Concept
K. Ryu; T. Yoshioka; S. Wakao; Y. Takahashi; K. Ishibashi; K. Fujiwara
IEEE TRANSACTIONS ON MAGNETICS, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 52(3), Mar. 2016, Scientific journal - Improvement of Convergence Characteristics of 1-D Dynamic Magnetic Field Analysis With Hysteresis for Iron Loss Estimation
Satoshi Doi; Tetsuya Aoki; Keiichi Okazaki; Yasuhito Takahashi; Koji Fujiwara
IEEE TRANSACTIONS ON MAGNETICS, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 52(3), Mar. 2016, Scientific journal - Simplified 3-D Modeling for Skewed Rotor Slots With End- Ring of Cage Induction Motors
Kazuki Yamada; Yasuhito Takahashi; Koji Fujiwara
IEEE TRANSACTIONS ON MAGNETICS, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 52(3) 8101604 , Mar. 2016, Scientific journal - Magnetic Field Analysis of Reactors for Power Conditioner System Taking Into Account Magnetic Hysteresis
Shoichi Kusakabe; Yasuhito Takahashi; Koji Fujiwara; Naohito Yamada
IEEE TRANSACTIONS ON MAGNETICS, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 52(3), Mar. 2016, Scientific journal - Parallel Finite-Element Analysis of Rotating Machines Based on Domain Decomposition Considering Nonconforming Mesh Connection
Yasuhito Takahashi; Koji Fujiwara; Takeshi Iwashita; Hiroshi Nakashima
IEEE TRANSACTIONS ON MAGNETICS, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 52(3) 7401604 , Mar. 2016, Scientific journal - Development of Local Expansion Edge Element for Magnetic Field Analysis
Yuki Wakayama; Yuichiro Hosobuchi; Ryunosuke Shimoyama; Shinji Wakao; Tadashi Tokumasu; Yasuhito Takahashi; Koji Fujiwara
2016 IEEE CONFERENCE ON ELECTROMAGNETIC FIELD COMPUTATION (CEFC), IEEE, 2016, International conference proceedings - Safety Performance Simulation for the Effect of a Photovoltaic Module Output Difference in Mega Solar Photovoltaic Systems
Naotaka Oka; Yasuhito Takahashi; Koji Fujiwara; Kazuyuki Hidaka; Hiroshi Morita
2016 IEEE REGION 10 HUMANITARIAN TECHNOLOGY CONFERENCE (R10-HTC), IEEE, 2016, International conference proceedings - Homogenization Method for Laminated Iron Core Taking Account of Hysteretic Property
Junji Kitao; Yasuhito Takahashi; Koji Fujiwara; Akira Ahagon; Tetsuji Matsuo; Akihiro Daikoku
2016 IEEE CONFERENCE ON ELECTROMAGNETIC FIELD COMPUTATION (CEFC), IEEE, 2016, International conference proceedings - The domain structure model including pinning effect based on the statistical distribution function
S. Ito; T. Mifune; T. Matsuo; C. Kaido; Y. Takahashi; K. Fujiwara
2016 IEEE CONFERENCE ON ELECTROMAGNETIC FIELD COMPUTATION (CEFC), IEEE, 2016, International conference proceedings - Complex-Valued Formulation of Nonlinear Time-Harmonic Magnetic Field Analysis and New Krylov-Like Solvers
Takeshi Mifune; Yasuhito Takahashi; Koji Fujiwara
2016 IEEE CONFERENCE ON ELECTROMAGNETIC FIELD COMPUTATION (CEFC), IEEE, 2016, International conference proceedings - Steady-State Analysis of Hysteretic Magnetic Field Problems Using Parallel TP-EEC Method
Y. Takahashi; J. Kitao; K. Fujiwara; A. Ahagon; T. Matsuo; T. Iwashita; H. Nakashima
2016 IEEE CONFERENCE ON ELECTROMAGNETIC FIELD COMPUTATION (CEFC), IEEE, 2016, International conference proceedings - Reverse Current Simulation in PV Array Composed of Different Modules for Interchangeability Evaluation of Thin Film PV Modules
Naotaka Oka; Takeshi Baba; Yasuhito Takahashi; Koji Fujiwara; Yoshiyuki Ishihara; Ei Ko; Shogo Nishikawa; Hiroshi Kato
2016 IEEE 43RD PHOTOVOLTAIC SPECIALISTS CONFERENCE (PVSC), IEEE, 3242 - 3246, 2016, International conference proceedings - Improvement of alternating magnetic characteristics represented by play model
Junji Kitao; Yasuhito Takahashi; Koji Fujiwara; Akira Ahagon; Tetsuji Matsuo; Akihiro Daikoku
INTERNATIONAL JOURNAL OF APPLIED ELECTROMAGNETICS AND MECHANICS, IOS PRESS, 52(3-4) 1425 - 1432, 2016, Scientific journal - A single sheet tester of Fe-based amorphous strip used for round robin test for IEC standardization
Masaya Tanaka; Hiroto Hagihara; Yasuhito Takahashi; Koji Fujiwara; Yoshiyuki Ishihara; Daichi Azuma
International Journal of Applied Electromagnetics and Mechanics, IOS Press, 48(2-3) 135 - 141, 30 Jun. 2015, Scientific journal - Equivalent circuit modeling of dynamic hysteretic property of silicon steel under pulse width modulation excitation
T. Miyazaki; T. Mifune; T. Matsuo; Y. Shindo; Y. Takahashi; K. Fujiwara
Journal of Applied Physics, American Institute of Physics Inc., 117(17) 17D110 , 07 May 2015, Scientific journal - Computational accuracy enhancement in magnetic field analysis by using orthogonalized infinite edge element method
Kenta Tsuzaki; Yoshihiro Tawada; Shinji Wakao; Akihisa Kameari; Tadashi Tokumasu; Yasuhito Takahashi; Hajime Igarashi; Koji Fujiwara; Yoshiyuki Ishihara
Electrical Engineering in Japan (English translation of Denki Gakkai Ronbunshi), John Wiley and Sons Inc., 191(1) 20 - 28, 01 Apr. 2015, Scientific journal - Parallel TP-EEC method based on phase conversion for time-periodic nonlinear magnetic field problems
Yasuhito Takahashi; Tadashi Tokumasu; Koji Fujiwara; Takeshi Iwashita; Hiroshi Nakashima
IEEE Transactions on Magnetics, Institute of Electrical and Electronics Engineers Inc., 51(3), 01 Mar. 2015, Scientific journal - Iron loss estimation method for rotating machines taking account of hysteretic property
Yoshimi Takeda; Yasuhito Takahashi; Koji Fujiwara; Akira Ahagon; Tetsuji Matsuo
IEEE Transactions on Magnetics, Institute of Electrical and Electronics Engineers Inc., 51(3) 7300504 , 01 Mar. 2015, Scientific journal - Analysis of induced electric field in human body by utility power frequency magnetic field using parallel fast multipole-accelerated boundary element method
Yasuhito Takahashi; Akira Ahagon; Koji Fujiwara; Takeshi Iwashita; Hiroshi Nakashima
IET Science, Measurement and Technology, Institution of Engineering and Technology, 9(2) 178 - 183, 01 Mar. 2015, Scientific journal - Fast nonlinear finite element analysis using Newton-Raphson method implemented by Krylov subspace method with relaxed convergence criterion
Yoshifumi Okamoto; Akihisa Kameari; Koji Fujiwara; Tomonori Tsuburaya; Shuji Sato
COMPEL-THE INTERNATIONAL JOURNAL FOR COMPUTATION AND MATHEMATICS IN ELECTRICAL AND ELECTRONIC ENGINEERING, EMERALD GROUP PUBLISHING LTD, 34(5) 1537 - 1552, 2015, Scientific journal - Modeling of Nonlinear Magnetizing Characteristics of Pole Transformer for Analyzing Islanding Prevention of Photovoltaic System
Yoshiaki Yoshida; Hirokazu Suzuki; Koji Fujiwara; Yoshiyuki Ishihara
ELECTRICAL ENGINEERING IN JAPAN, WILEY-BLACKWELL, 188(3) 46 - 55, Aug. 2014, Scientific journal - Estimation of Magnetizing Characteristics of Pole Transformers in Islanding Area
Yoshiaki Yoshid; Hirokazu Suzuki; Koji Fujiwara; Yoshiyuki Ishihara
ELECTRICAL ENGINEERING IN JAPAN, WILEY-BLACKWELL, 187(3) 47 - 59, May 2014, Scientific journal - Standard Measurement Method for Magnetic Properties of Fe-Based Amorphous Magnetic Materials
Hiroto Hagihara; Masaya Tanaka; Yasuhito Takahashi; Koji Fujiwara; Yoshiyuki Ishihara
IEEE TRANSACTIONS ON MAGNETICS, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 50(4) 6100604 , Apr. 2014, Scientific journal - Magnetic Properties Evaluation of Grain-Oriented Electrical Steel Sheets under Bending Stress
Hiroto Hagihara; Yasuhito Takahashi; Koji Fujiwara; Yoshiyuki Ishihara; Tsuyoshi Masuda
IEEE TRANSACTIONS ON MAGNETICS, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 50(4) 2002104 , Apr. 2014, Scientific journal - Performance of preconditioned linear solvers based on minimum residual for complex symmetric linear systems
Tomonori Tsuburaya; Yoshifumi Okamoto; Koji Fujiwara; Shuji Sato
IEEE Transactions on Magnetics, 50(2), Feb. 2014, Scientific journal - Comparison Between Modeling Methods of 2-D Magnetic Properties in Magnetic Field Analysis of Synchronous Machines
Shingo Higuchi; Yasuhito Takahashi; Tadashi Tokumasu; Koji Fujiwara
IEEE TRANSACTIONS ON MAGNETICS, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 50(2) 7009104 , Feb. 2014, Scientific journal - Improvement of Unified Boundary Integral Equation Method in Magnetostatic Shielding Analysis
Kazuhisa Ishibashi; Takuya Yoshioka; Shinji Wakao; Yasuhito Takahashi; Zoran Andjelic; Koji Fujiwara
IEEE TRANSACTIONS ON MAGNETICS, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 50(2), Feb. 2014, Scientific journal - Loss Calculation Method Considering Hysteretic Property With Play Model in Finite Element Magnetic Field Analysis
Junji Kitao; Yoshimi Takeda; Yasuhito Takahashi; Koji Fujiwara; Akira Ahagon; Tetsuji Matsuo
IEEE TRANSACTIONS ON MAGNETICS, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 50(2) 7009304 - 384, Feb. 2014, Scientific journal - Basic study on islanding detection method for pv systems by harmonic impedance detection in case of including induction motor in load system
Yoshiaki Yoshida; Hirokazu Suzuki; Koji Fujiwara; Yoshiyuki Ishihara
IEEJ Transactions on Power and Energy, Institute of Electrical Engineers of Japan, 134(5) 399 - 411, 2014, Scientific journal - Experimental verification in case of mixed connection in PV inverters using different active islanding detection methods
Yoshiaki Yoshida; Hirokazu Suzuki; Koji Fujiwara; Yoshiyuki Ishihara
IEEJ Transactions on Industry Applications, 134(2) 165 - 174, 2014, Scientific journal - Study on interrelationship of PV modules-simulation of reverse voltage taking account of MPPT control method in PCS-
Kosuke Horie; Yasuhito Takahashi; Koji Fujiwara; Yoshiyuki Ishihara; Katsuya Takahashi; Shogo Nishikawa; Hiroshi Kato
IEEJ Transactions on Power and Energy, Institute of Electrical Engineers of Japan, 134(8) 673 - 681, 2014, Scientific journal - On the practical implementation of ICCG method solving real symmetric linear equation arising in edge-based finite element analysis
Yoshifumi Okamoto; Yasuhito Takahashi; Koji Fujiwara; Akira Ahagon; Takeshi Mifune; Takeshi Iwashita
IEEJ Transactions on Power and Energy, Institute of Electrical Engineers of Japan, 134(9) 767 - 776, 2014, Scientific journal - Magnetic Field Analysis in Far-Field Region by Infinite Edge Element With Boundary Surface Integration
T. Yoshioka; Y. Tawada; K. Tsuzaki; S. Wakao; A. Kameari; T. Tokumasu; Y. Takahashi; H. Igarashi; K. Fujiwara
IEEE TRANSACTIONS ON MAGNETICS, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 49(5) 1681 - 1684, May 2013, Scientific journal - Development of islanding detection device for PV inverters by harmonic impedance detection and performance verification using resonant circuit
Yoshiaki Yoshida; Hirokazu Suzuki; Koji Fujiwara; Yoshiyuki Ishihara
IEEJ Transactions on Industry Applications, 133(10) 961 - 969, 2013, Scientific journal - Improvement of the preconditioned MRTR method with eisenstat's technique in real symmetric sparse matrices
Tomonori Tsuburaya; Yoshifumi Okamoto; Koji Fujiwara; Shuji Sato
IEEE Transactions on Magnetics, 49(5) 1641 - 1644, 2013, Scientific journal - Experimental study of islanding-prevention method by harmonic injection synchronized to exciting current harmonics of pole transformer
Yoshiaki Yoshida; Hirokazu Suzuki; Koji Fujiwara; Yoshiyuki Ishihara
IEEJ Transactions on Power and Energy, 133(1) 79 - 90, 2013, International conference proceedings - Modeling of nonlinear magnetizing characteristics of pole transformer for analyzing islanding-prevention of photovoltaic system
Yoshiaki Yoshida; Hirokazu Suzuki; Koji Fujiwara; Yoshiyuki Ishihara
IEEJ Transactions on Industry Applications, 133(1) 56 - 63, 2013, Scientific journal - Computational accuracy enhancement in magnetic field analysis by using orthogonalized infinite edge element method
Kenta Tsuzaki; Yoshihiro Tawada; Shinji Wakao; Akihisa Kameari; Tadashi Tokumasu; Yasuhito Takahashi; Hajime Igarashi; Koji Fujiwara; Yoshiyuki Ishihara
IEEJ Transactions on Power and Energy, 133(5) 8 - 472, 2013, Scientific journal - Nonlinear magnetostatic analysis by unified BIE utilizing potential gap due to loop currents
Kazuhisa Ishibashi; Zoran Andjelic; Yasuhito Takahashi; Yoshihiro Tawada; Takuya Yoshioka; Shinji Wakao; Koji Fujiwara; Yoshiyuki Ishihara
IEEE Transactions on Magnetics, 49(5) 1573 - 1576, 2013, Scientific journal - Time-domain parallel finite-element method for fast magnetic field analysis of induction motors
Yasuhito Takahashi; Tadashi Tokumasu; Masafumi Fujita; Takeshi Iwashita; Hiroshi Nakashima; Shinji Wakao; Koji Fujiwara
IEEE Transactions on Magnetics, 49(5) 2413 - 2416, 2013, Scientific journal - Automatic determination of acceleration factor based on residual and functional in shifted ICCG method for 3-D electromagnetic field analyses
Junji Kitao; Yasuhito Takahashi; Koji Fujiwara; Takeshi Mifune; Takeshi Iwashita
IEEE Transactions on Magnetics, 49(5) 1741 - 1744, 2013, Scientific journal - Orthogonalized Infinite Edge Element Method-Convergence Improvement by Orthogonalization of Hilbert Matrix in Infinite Edge Element Method
S. Tamitani; K. Tsuzaki; Shinji Wakao; T. Tokumasu; Y. Takahashi; A. Kameari; H. Igarashi; K. Fujiwara; Y. Ishihara
IEEE TRANSACTIONS ON MAGNETICS, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 48(2) 363 - 366, Feb. 2012, Scientific journal - Magnetic Field Evaluation at Vertex by Boundary Integral Equation Derived From Scalar Potential of Double Layer Charge
K. Ishibashi; Z. Andjelic; Y. Takahashi; T. Takamatsu; T. Fukuzumi; S. Wakao; K. Fujiwara; Y. Ishihara
IEEE TRANSACTIONS ON MAGNETICS, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 48(2) 459 - 462, Feb. 2012, Scientific journal - Some Treatments of Fictitious Volume Charges in Nonlinear Magnetostatic Analysis by BIE
K. Ishibashi; Z. Andjelic; Y. Takahashi; T. Takamatsu; K. Tsuzaki; S. Wakao; K. Fujiwara; Y. Ishihara
IEEE TRANSACTIONS ON MAGNETICS, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 48(2) 463 - 466, Feb. 2012, Scientific journal - Comparison between fast steady-state analysis methods for time-periodic nonlinear magnetic field problems
Yasuhito Takahashi; Tadashi Tokumasu; Masafumi Fujita; Shinji Wakao; Koji Fujiwara; Yoshiyuki Ishihara
IEEE Transactions on Magnetics, 48(2) 235 - 238, Feb. 2012, International conference proceedings - Parallel time-periodic finite-element method for steady-state analysis of rotating machines
Yasuhito Takahashi; Takeshi Iwashita; Hiroshi Nakashima; Tadashi Tokumasu; Masafumi Fujita; Shinji Wakao; Koji Fujiwara; Yoshiyuki Ishihara
IEEE Transactions on Magnetics, 48(2) 1019 - 1022, Feb. 2012, International conference proceedings - Performance verification of new active islanding detection methods for PV system by simulation
Yoshiaki Yoshida; Koji Fujiwara; Yoshiyuki Ishihara; Hirokazu Suzuki
2012 International Conference on Renewable Energy Research and Applications, ICRERA 2012, 2012, International conference proceedings - Estimation of magnetizing characteristics of pole transformer in islanding area
Yoshiaki Yoshida; Hirokazu Suzuki; Koji Fujiwara; Yoshiyuki Ishihara
IEEJ Transactions on Industry Applications, 132(8) 7 - 835, 2012, Scientific journal - Magnetostatic analysis by BEM with magnetic double layer as unknown utilizing volume magnetic charge
Kazuhisa Ishibashi; Zoran Andjelic; Yasuhito Takahashi; Tomoaki Takamatsu; Kenta Tsuzaki; Shinji Wakao; Koji Fujiwara; Yoshiyuki Ishihara
International Journal of Applied Electromagnetics and Mechanics, 39(1-4) 711 - 717, 2012, International conference proceedings - Magnetic field analysis of ring core taking account of hysteretic property using play model
Junji Kitao; Kazushige Hashimoto; Yasuhito Takahashi; Koji Fujiwara; Yoshiyuki Ishihara; Akira Ahagon; Tetsuji Matsuo
IEEE Transactions on Magnetics, 48(11) 3375 - 3378, 2012, Scientific journal - Micromagnetic Simulations of Perpendicular Recording Head Using the Parallel Fast Multipole Method Specialized for Uniform Brick Elements
Yasuhito Takahashi; Takeshi Iwashita; Hiroshi Nakashima; Shinji Wakao; Koji Fujiwara; Yoshiyuki Ishihara
IEEE TRANSACTIONS ON MAGNETICS, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 47(10) 3805 - 3808, Oct. 2011, Scientific journal - 誘導電動機の回転子スロット数が電磁力に与える影響
舘 洸史; 髙橋康人; 藤原耕二; 石原好之; 北川 亘; 井上敦司; 刀谷郁也
日本AEM学会誌, 19(2) 149 - 154, Jun. 2011 - Convergence Acceleration in Steady State Analysis of Synchronous Machines Using Time-Periodic Explicit Error Correction Method
Yasuhito Takahashi; Hiroyuki Kaimori; Akihisa Kameari; Tadashi Tokumasu; Masafumi Fujita; Shinji Wakao; Takeshi Iwashita; Koji Fujiwara; Yoshiyuki Ishihara
IEEE TRANSACTIONS ON MAGNETICS, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 47(5) 1422 - 1425, May 2011, Scientific journal - Performance Evaluation of a Parallel Fast Multipole Accelerated Boundary Integral Equation Method in Electrostatic Field Analysis
Yasuhito Takahashi; Takeshi Iwashita; Hiroshi Nakashima; Shinji Wakao; Koji Fujiwara; Yoshiyuki Ishihara
IEEE TRANSACTIONS ON MAGNETICS, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 47(5) 1174 - 1177, May 2011, Scientific journal - Large-scale analysis of magnetic particle dynamics taking into account contact force and magnetic interaction with the fast multipole method
Takuya Tatsuishi; Yasuhito Takahashi; Masahiko Miwa; Shinji Wakao; Koji Fujiwara; Yoshiyuki Ishihara
JOURNAL OF APPLIED PHYSICS, AMER INST PHYSICS, 109(7), Apr. 2011, Scientific journal - 双方向DC_DC コンバータにおけるスイッチング素子出力容量の回路動作への影響について
加藤 正幸; 高橋 康人; 藤原 耕二; 石原 好之; 小倉 正嗣; 蓑輪 義文; 栗尾 信広
パワーエレクトロニクス学会誌, The Japan Institute of Power Electronics, 36 191 - 191, 2011 - Effectiveness of Higher Order Time Integration in Time-Domain Finite-Element Analysis
Yoshifumi Okamoto; Koji Fujiwara; Yoshiyuki Ishihara
IEEE TRANSACTIONS ON MAGNETICS, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 46(8) 3321 - 3324, Aug. 2010, Scientific journal - Design of a reactor driven by inverter power supply to reduce the noise considering electromagnetism and magnetostriction
Yanhui Gao; Kazuhiro Muramatsu; Muhd Juzail Hatim; Koji Fujiwara; Yoshiyuki Ishihara; Shigemasa Fukuchi; Tetsumi Takahata
IEEE Transactions on Magnetics, 46(6) 2179 - 2182, Jun. 2010, International conference proceedings - Proposal for a benchmark model of a laminated iron core and a large-scale and highly accurate magnetic analysis
Yasuhito Takahashi; Shinji Wakao; Koji Fujiwara; Hiroyuki Kaimori; Akihisa Kameari
Electrical Engineering in Japan (English translation of Denki Gakkai Ronbunshi), 170(1) 26 - 35, 15 Jan. 2010, Scientific journal - Structure deformation analysis caused by magnetostriction of magnetic steel sheet using combination of electromagnetic and structure analysis
Wataru Kitagawa; Koji Fujiwara; Yoshiyuki Ishihara
19th International Conference on Electrical Machines, ICEM 2010, 2010, International conference proceedings - Fast magnetic field analysis by applying nonconforming mesh connection technique to an outer region
Yoshifumi Okamoto; Koji Fujiwara; Yoshiyuki Ishihara; Shuji Sato
Digests of the 2010 14th Biennial IEEE Conference on Electromagnetic Field Computation, CEFC 2010, 2010, International conference proceedings - Convergence acceleration in transient analysis of rotating machines using time-periodic explicit error correction method
Yasuhito Takahashi; Hiroyuki Kaimori; Akihisa Kameari; Tadashi Tokumasu; Masafumi Fujita; Shinji Wakao; Takeshi Iwashita; Koji Fujiwara; Yoshiyuki Ishihara
Digests of the 2010 14th Biennial IEEE Conference on Electromagnetic Field Computation, CEFC 2010, 2010, International conference proceedings - Coupled analysis of electromagnetic wave and heat conduction with rotational motion of heated target and temperature-dependent complex permittivity
Yoshifumi Okamoto; Ryutaro Himeno; Kiminori Ushida; Akira Ahagon; Koji Fujiwara
Electrical Engineering in Japan (English translation of Denki Gakkai Ronbunshi), 169(1) 902 - 910, Oct. 2009, Scientific journal - Study of control method under the 30-min balancing rule for a PV system
Motohiro Nishihata; Koji Fujiwara; Yoshiyuki Ishihara; Toshiyuki Todaka; Toshihisa Funabashi; Hironori Nakashima; Yoshimichi Okuno
Solar Energy Materials and Solar Cells, 93(6-7) 1158 - 1162, Jun. 2009, Scientific journal - Exact minimization of energy functional for nr method with line-search technique
Yoshifumi Okamoto; Koji Fujiwara; Ryutaro Himeno
IEEE Transactions on Magnetics, 45(3) 1288 - 1291, Mar. 2009, Scientific journal - Database design for magnetic properties oriented to electromagnetic field analysis
Wataru Kitagawa; Yosuke Hattori; Koji Fujiwara; Yoshiyuki Ishihara; Toshiyuki Todaka
IEEJ Transactions on Industry Applications, 129(11) 1 - 1021, 2009, Scientific journal - Analysis of structural deformation and vibration of electrical steel sheet by using magnetic property of magnetostriction
Wataru Kitagawa; Koji Fujiwara; Yoshiyuki Ishihara; Toshiyuki Todaka
Studies in Applied Electromagnetics and Mechanics, 30 47 - 50, 2008, International conference proceedings - 積層鉄芯ベンチマークモデルの提案とその高精度磁界解析
高橋康人; 若尾真治; 藤原耕二; 貝森弘行; 亀有昭久
電気学会論文誌B, The Institute of Electrical Engineers of Japan, 127-B(8) 894 - 901, Aug. 2007 - Large-scale magnetic field analysis of laminated core by using the hybrid finite element and boundary element method combined with the fast multipole method
Yasuhito Takahashi; Shinji Wakao; Koji Fujiwara; Seiji Fujino
IEEE Transactions on Magnetics, 43(6) 2971 - 2973, Jun. 2007, International conference proceedings - FEM computation of magnetic field and iron loss in laminated iron core using homogenization method
Hiroyuki Kaimori; Akihisa Kameari; Koji Fujiwara
IEEE TRANSACTIONS ON MAGNETICS, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 43(4) 1405 - 1408, Apr. 2007, Scientific journal - The coupled analysis of electromagnetic wave and heat conduction with rotational motion of heated target and temperature-dependent complex permittivity
Yoshifumi Okamoto; Ryutaro Himeno; Kiminori Ushida; Akira Ahagon; Koji Fujiwara
IEEJ Transactions on Power and Energy, 127(8), 2007, Scientific journal - Magnetic disturbance due to the hemispherical hole in the ground for a building at the magnetic test site
Keita Yamazaki; Yasutoshi Hyakusoku; Kazuhiro Muramatsu; Hideki Kitamura; Koji Fujiwara; Koichiro Kobayashi
IEEE Transactions on Magnetics, 42(10) 3530 - 3532, Oct. 2006, Scientific journal - Convergence acceleration of the Newton-Raphson method using successive quadratic function approximation of residual
Chang Seop Koh; Jae Seop Ryu; Koji Fujiwara
IEEE Transactions on Magnetics, 42(4) 611 - 614, Apr. 2006, International conference proceedings - Nondestructive evaluation of irradiation embrittlement of SQV2A steel by using magnetic method
Mitsuharu Shiwa; Cheng Weiying; Shigeo Nakahigashi; Ichiro Komura; Koji Fujiwara; Norio Takahashi
AIP Conference Proceedings, 820 1163 - 1170, 06 Mar. 2006, International conference proceedings - Speedup of nonlinear iterative scheme by utilizing convergence characteristics of Newton-Raphson method and ICCG method
Yoshifumi Okamoto; Koji Fujiwara; Akihisa Kameari
12th Biennial IEEE Conference on Electromagnetic Field Computation, CEFC 2006, 2006, International conference proceedings - Surface integration free combined finite element method with Biot-Savart law
Koji Fujiwara; Yoshifumi Okamoto; Akihisa Kameari
12th Biennial IEEE Conference on Electromagnetic Field Computation, CEFC 2006, 2006, International conference proceedings - FEM computation of magnetic fields in anisotropic magnetic materials
Akihisa Kameari; Koji Fujiwara
IEEJ Transactions on Power and Energy, 126(2) 141 - 146, 2006, Scientific journal - Magnetic field analysis of laminated core by using homogenization method
H. Muto; Y. Takahashi; S. Wakao; K. Fujiwara; A. Kameari
Journal of Applied Physics, 99(8) 08H907 , 2006, Scientific journal - Application of fine-grained doubly oriented electrical steel to IPM synchronous motor
Toshiro Tomida; Naoyuki Sano; Shigeharu Hinotani; Koji Fujiwara; Hidetoshi Kotera; Noriyoshi Nishiyama; Yasufumi Ikkai
IEEE Transactions on Magnetics, 41(10) 4063 - 4065, Oct. 2005, International conference proceedings - Incremental permeability of mu-metal in low magnetic fields for the design of multilayer-type magnetically shielded rooms
Keita Yamazaki; Kazuo Kato; Kazuhiro Muramatsu; Akira Haga; Koichiro Kobayashi; Kiyotaka Kamata; Koji Fujiwara; Takao Yamaguchi
IEEE Transactions on Magnetics, 41(10) 4087 - 4089, Oct. 2005, International conference proceedings - Development of 3-D read/write simulation system for higher areal recording density
Naoya Fujiwara; Kiminari Shinagawa; Kohei Ashiho; Koji Fujiwara; Norio Takahashi
IEEE Transactions on Magnetics, 40(2) 838 - 841, Mar. 2004, International conference proceedings - Recent Trend of Magnetic Field Analysis : What's Next after Well-Grown Technology for 3-D Magnetic Field Analysis?
Fujiwara Koji
The Reference Collection of Annual Meeting, The Japan Society of Mechanical Engineers, 3 223 - 224, 2003 - Shielding Effect of DC Magnetic Field of Magnetically Shielded Rooms
Keita Yamazaki; Koji Fujiwara; Kohei Ashiho; Norio Takahashi
IEEJ Transactions on Fundamentals and Materials, 123(10) 1058 - 1064, 2003, Scientific journal - New structured planar write head for 100 Gb/in2 and beyond
Yasushi Kanai; Ryo Matsubara; Koji Fujiwara; Norio Takahashi
IEEE Transactions on Magnetics, 38(5 I) 2210 - 2212, Sep. 2002, International conference proceedings - A proposal of finite-element analysis considering two-dimensional magnetic properties
Koji Fujiwara; Takayuki Adachi; Norio Takahashi
IEEE Transactions on Magnetics, 38(2 I) 889 - 892, Mar. 2002, International conference proceedings - Magnetic field fluctuations due to movement of objects composed of magnetic materials
Keita Yamazaki; Kohei Ashio; Koji Fujiwara; Norio Takahashi
INTERMAG Europe 2002 - IEEE International Magnetics Conference, Institute of Electrical and Electronics Engineers Inc., 2002, International conference proceedings - A database-oriented eddy current loss estimation for the reactor windings of HVDC filters
Shuichi Nogawa; Kazunari Kajimura; Minoru Kuwata; Norio Takahashi; Koji Fujiwara
IEEE Transactions on Magnetics, 37(4 I) 2779 - 2782, Jul. 2001, International conference proceedings - Characteristics and prediction of magnetic noise due to dc electric railcars for biomagnetic measurements
Keita Yamazaki; Kazuo Kato; Koichiro Kobayashi; Yoshinori Uchikawa; Yoji Kumagai; Akira Haga; Koji Fujiwara
IEEE Transactions on Magnetics, 37(4 I) 2884 - 2887, Jul. 2001, International conference proceedings - Thin film write head field analysis using a benchmark problem
Koji Fujiwara; Fumiaki Ikeda; Akihisa Kameari; Yasushi Kanai; Kimio Nakamura; Norio Takahashi; Koji Tani; Takashi Yamada
IEEE Transactions on Magnetics, IEEE, 36(4 I) 1784 - 1787, Jul. 2000, Scientific journal - Improvements of single sheet testers for measurement of 2-d magnetic properties up to high flux density
Masanori Nakano; Hidehiko Nishimoto; Koji Fujiwara; Norio Takahashi
IEEE Transactions on Magnetics, 35(5) 3965 - 3967, 1999, Scientific journal - Single sheet tester having open magnetic path for measurement of magnetostriction of electrical steel sheet
Tomoya Nakase; Masanori Nakano; Koji Fujiwara; Norio
IEEE Transactions on Magnetics, 35(5) 3956 - 3958, 1999, Scientific journal - Some important properties of edge shape functions
A Ahagon; K Fujiwara
IEEE TRANSACTIONS ON MAGNETICS, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 34(5) 3311 - 3314, Sep. 1998, Scientific journal - Measuring system for magnetostriction of silicon steel sheet under ac excitation using optical methods
Tomoya Nakase; Masanori Nakano; Koji Fujiwara; Norio Takahashi
IEEE Transactions on Magnetics, IEEE, 34(4) 2072 - 2074, Jul. 1998, Scientific journal - Shielding effect of superconducting magnetically shielded room
Keita Yamazaki; Ken-Ichi Unno; Hironori Matsuba; Tomonori Watanabe; Daiichi Irisawa; Koji Fujiwara
IEEE Transactions on Magnetics, 33(5) 3451 - 3453, 1997, Scientific journal - Comparison of various kinds of edge elements for electromagnetic field analysis
Akira Ahagon; Koji Fujiwara; Takayoshi Nakata
IEEE Transactions on Magnetics, 32(3) 898 - 901, 1996, Scientific journal - Improvement of convergence characteristic of iccg method for the a-0 method using edge elements
Koji Fujiwara; Takayoshi Nakata; Hiromitsu Ohashi
IEEE Transactions on Magnetics, 32(3) 804 - 806, 1996, Scientific journal - Linear ac steady-state eddy current analysis of high speed conductor using moving coordinate system
Kazuhiro Muramatsu; Takayoshi Nakata; Norio Takahashi; Koji Fujiwara
IEEE Transactions on Magnetics, 32(3) 749 - 752, 1996, Scientific journal - Acceleration technique of waveform control for single sheet tester
Kazunori Matsubara; Norio Takahashi; Koji Fujiwara; Takayoshi Nakata; Masanori Nakano; Hitoshi Aoki
IEEE Transactions on Magnetics, 31(6) 3400 - 3402, 1995, Scientific journal - Effects of impedances of primary winding and mutual inductor on distortion of flux waveform in single sheet tester
Kazunori Matsubara; Norio Takahashi; Takayoshi Nakata; Koji Fujiwara; Masanori Nakano; Akio Date
IEEE Transactions on Magnetics, 31(6) 3382 - 3384, 1995, Scientific journal - On the Continuity of the Magnetizing Current Density in 3-D Magnetic Field Analysis with Edge Element
Koji Fujiwara; Takayoshi Nakata; Norio Takahashi; Hiromitsu Ohashi
IEEE Transactions on Magnetics, 31(3) 1364 - 1367, 1995, Scientific journal - Nonlinear Transient Analysis of Electric Field Coupled with Temperature at the Joint of a Power Cable
Norio Takahashi; Koji Fujiwara; Takayoshi Nakata; Yoichi Ogura; Yoshio Mizutani; Ken Yatsuka
IEEE Transactions on Magnetics, 31(3) 1900 - 1903, 1995, Scientific journal - Practical Analysis of 3-D Dynamic Nonlinear Magnetic Field Using Time-Periodic Finite Element Method
Takayoshi Nakata; Norio Takahashi; Koji Fujiwara; Kazuhiro Muramatsu; Hiromitsu Ohashi; Hui Ling Zhu
IEEE Transactions on Magnetics, 31(3) 1416 - 1419, 1995, Scientific journal - Method for analyzing eddy currents in moving conductors
Kazuhiro Muramatsu; Takayoshi Nakata; Norio Takahashi; Koji Fujiwara
Electrical Engineering in Japan, 114(7) 102 - 114, 1994, Scientific journal - Fast Actuator Modeling by Finite Element Method
Keizo Takeuchi; Masaki Shimizu; Keiichi Okazaki; Norio Takahashi; Koji Fujiwara
IEEE Transactions on Magnetics, 30(6) 4284 - 4286, 1994, Scientific journal
MISC
- Comparison of Localized and Additive Schwarz Preconditioning in Parallel Finite-element Analysis of Electric Machines Using Domain Decomposition Method
高橋康人; 貝森弘行; 藤原耕二; 岩下武史
電気学会全国大会講演論文集(CD-ROM), 2023, 2023 - Magnetic Field Analysis of Electric Machines Taking Account of Hysteretic Property Using Parallel-in-Space-and-Time Finite-Element Method
高橋康人; 藤原耕二; 岩下武史
電気学会研究会資料(Web), (SA-23-018-032/RM-23-018-032), 2023 - Circuit Simulation of a FEM-parameterized Plant Model for a Permanent Magnet Synchronous Motor Based on Semi-implicit Time Integration Method
高橋康人; 阿波根明; 飛田美和; 松尾哲司; 藤原耕二
電気学会研究会資料(Web), (SA-23-069-080/RM-23-068-079), 2023 - Stray Loss Evaluation of a Ductile Cast Iron Frame in a Permanent Magnet Synchronous Motor
後藤峻平; 高橋康人; 藤原耕二; 松下真琴; 竹内活徳
電気学会研究会資料(Web), (MD-23-118-137/RM-23-093-112), 2023 - 平角線コイルベンチマークモデルの銅損評価に関する検討—Copper Loss Evaluation of Flat Wire Coil Benchmark Models—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
井口 達馬; 髙橋 康人; 藤原 耕二
電気学会研究会資料. SA / 電気学会静止器研究会 [編], 2022(18-32) 67 - 72, 08 Mar. 2022 - マルチポートCLN法を用いたスキューを有するかご形誘導電動機のモデル縮約に関する検討—Model Order Reduction of Cage Induction Motor with Skewed Rotor Slots Using Multi-port Cauer Ladder Network Method—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
安井 昌輝; 髙橋 康人; 藤原 耕二; 菅原 賢悟; 松尾 哲司
電気学会研究会資料. RM / 電気学会回転機研究会 [編], 2022(18-32) 61 - 66, 08 Mar. 2022 - マルチポートCLN法を用いたスキューを有するかご形誘導電動機のモデル縮約に関する検討—Model Order Reduction of Cage Induction Motor with Skewed Rotor Slots Using Multi-port Cauer Ladder Network Method—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
安井 昌輝; 髙橋 康人; 藤原 耕二; 菅原 賢悟; 松尾 哲司
電気学会研究会資料. SA / 電気学会静止器研究会 [編], 2022(18-32) 61 - 66, 08 Mar. 2022 - 直列共振を利用した電力変換回路用リアクトルの高周波損失測定法に関する検討—Loss Evaluation of High-Frequency Reactors for Power Conversion Circuit Using Series Resonance—モータドライブ/家電・民生合同研究会・モータドライブ一般/家電・民生一般
上川 浩輝; 光武 義雄; 岡田 健治; 髙橋 康人; 藤原 耕二
電気学会研究会資料. HCA / 家電・民生研究会 [編], 2022(1-20) 9 - 14, 01 Mar. 2022 - Performance Evaluation of Large-scale Magnetic Field Analysis Using Parallel-in-space-and-time Finite-element Method based on Domain Decomposition and Parallel TP-EEC Method in Massively Parallel Computing Environment
高橋康人; 藤原耕二; 岩下武史
電気学会研究会資料, (SA-21-001-014/RM-21-001-014), 2021 - Feature Extraction of Magnetic Circuits Using Convolutional Neural Networks (2): Multi-task learning of images for synchronous reluctance motor
田中眞之; 桂井麻里衣; 高橋康人; 藤原耕二
電気学会研究会資料, (SA-21-015-028/RM-21-015-028), 2021 - Transient Analysis of Cage Induction Motor Coupled with Control System Using Behavioral Modeling based on Multi-port Cauer Ladder Network Method
宇野賢; 高橋康人; 藤原耕二; 菅原賢悟; 松尾哲司
電気学会研究会資料, (SA-21-015-028/RM-21-015-028), 2021 - Verification of Validity of Behavioral Modeling for Permanent Magnet Synchronous Motor Considering Harmonic Losses and Stator End-winding Leakage Inductance in Overmodulation Region of PWM Inverters
辻川昌太朗; 高橋康人; 藤原耕二
電気学会研究会資料, (SA-21-015-028/RM-21-015-028), 2021 - Iron Loss Estimation of Soft Magnetic Materials for Power Transformers Considering Hysteretic Properties
武田真帆; 高橋康人; 藤原耕二; 今盛聡
電気学会論文誌 B, 141(8), 2021 - Application of a Multi-Port Cauer Ladder Network Method to Cage Induction Motors
宇野 賢; 髙橋 康人; 藤原 耕二; 菅原 賢悟; 松尾 哲司
電気学会研究会資料. RM, 電気学会, 2020(75) 109 - 114, 04 Sep. 2020 - Application of a Multi-Port Cauer Ladder Network Method to Cage Induction Motors
宇野 賢; 髙橋 康人; 藤原 耕二; 菅原 賢悟; 松尾 哲司
電気学会研究会資料. SA, 電気学会, 2020(51) 109 - 114, 04 Sep. 2020 - 非線形時間調和渦電流解析のためのヤコビ行列の対称性を利用したILU前処理—ILU Preconditioning Utilizing the Symmetricity of Jacobian Matrices for Nonlinear Time-Harmonic Eddy-Current Analysis—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
長嶺 英朗; 美舩 健; 松尾 哲司; 髙橋 康人; 藤原 耕二
電気学会研究会資料. SA / 電気学会静止器研究会 [編], 東京 : 電気学会, 2020(1-9・11-15) 35 - 38, 23 Jan. 2020 - Evaluation of Machine Performance of Fixed Outer Rotor Three-Phase Cage Induction Motor Using Finite-element Method
安井昌輝; 高橋康人; 藤原耕二; 貝森弘行
電気学会研究会資料, (SA-20-051-070/RM-20-075-094), 2020 - Estimation of Quasi-DC Hysteresis Property by Using LLG Equation
梶原千聖; 高橋康人; 藤原耕二
電気学会研究会資料, (SA-20-051-070/RM-20-075-094), 2020 - Feature Extraction of Magnetic Circuits Using Convolutional Neural Networks
田中眞之; 桂井麻里衣; 高橋康人; 藤原耕二
電気学会研究会資料, (SA-20-031-050/RM-20-055-074), 2020 - Iron Loss Estimation of Soft Magnetic Materials for Power Transformers Considering Hysteretic Properties
武田真帆; 高橋康人; 藤原耕二; 今盛聡
電気学会研究会資料, (SA-20-031-050/RM-20-055-074), 2020 - Investigation on International Standardization of Magnetostriction Measurement of Grain-oriented Electrical Steel Sheets
梶原千聖; 高橋康人; 藤原耕二
電気学会研究会資料, (SA-20-096-101), 2020 - Investigation on Iron Losses of Series Reactors for High Voltage Power Capacitors (Part 1)-Iron Loss Evaluation by Means of a Single Sheet Tester-
狩野秀明; 前地洋明; 桑田稔; 桑田稔; 高橋康人; 藤原耕二
電気学会研究会資料, (SA-20-096-101), 2020 - Simplified 3-D Modeling of Permanent Magnet Synchronous Motors for Efficient Evaluation of Magnet Eddy-current Losses
松田直也; 高橋康人; 藤原耕二
電気学会研究会資料, (SA-20-016-030/RM-20-016-030), 2020 - Power Generation and Safety Performance of Photovoltaic System when Mixing Photovoltaic Modules with Different Installation Angles
Mitsuhiko Suetsugu; Yasuhito Takahashi; Koji Fujiwara
2018 IEEE 7th World Conference on Photovoltaic Energy Conversion, WCPEC 2018 - A Joint Conference of 45th IEEE PVSC, 28th PVSEC and 34th EU PVSEC, 2351 - 2356, 26 Nov. 2018 - Large-scale Magnetic Field Analysis of Electric Machines Using Parallel Finite-element Method Based on Domain Decomposition and Parareal
髙橋 康人; 藤原 耕二; 徳増 正; 岩下 武史; 中島 浩
電気学会研究会資料. RM, 電気学会, 2018(72) 11 - 16, 21 Aug. 2018 - Study of Computation Method of Iron Loss Considering Magnetic Anisotropy by Processing Residual Stress
Satoshi Doi; Tetsuya Aoki; Keiichi Okazaki; Yasuhito Takahashi; Koji Fujiwara
Electrical Engineering in Japan (English translation of Denki Gakkai Ronbunshi), John Wiley and Sons Inc., 204(1) 29 - 39, 01 Jul. 2018 - Large-scale Magnetic Field Analysis of Electric Machines Using Parallel Finite-element Method Based on Space-time Domain Decomposition Method
髙橋 康人; 藤原 耕二; 岩下 武史; 中島 浩
電気学会研究会資料. SA, 電気学会, 2018(16) 5 - 10, 24 Jan. 2018 - Machine Performance of IEEJ Benchmark Model for Interior Permanent Magnet Synchronous Motor with Concentrated Winding(Pt. 2)
習田 祐作; 髙橋 康人; 藤原 耕二
電気学会研究会資料. RM, 電気学会, 2017(98) 59 - 64, 22 Sep. 2017 - Magnetic Field Analysis of Interior Permanent Magnet Synchronous Motor in Finite Element Method Considering Hysteretic Property(Pt. 2)
北尾 純士; 髙橋 康人; 藤原 耕二; 阿波根 明; 松尾 哲司; 大穀 晃裕
電気学会研究会資料. RM, 電気学会, 2017(98) 53 - 58, 22 Sep. 2017 - Magnetic Field Analysis of Cage Induction Motor Using Parallel TP-EEC Method Considering Polyphase Time-periodic Condition
髙橋 康人; 藤原 耕二; 徳増 正; 岩下 武史; 中島 浩
電気学会研究会資料. RM, 電気学会, 2017(98) 13 - 18, 22 Sep. 2017 - Modeling of Frequency-dependent Magnetic Properties of Soft Magnetic Composite Based on Cauer Circuit
渡邉 直也; 髙橋 康人; 藤原 耕二; 堺 香代; 島津 英一郎
電気学会研究会資料. RM, 電気学会, 2017(83) 73 - 78, 21 Sep. 2017 - Air-flux Compensation Method for Measurement of Saturation Magnetization of Magnetic Material Using Electromagnet
芝滝 拓哉; 髙橋 康人; 藤原 耕二
電気学会研究会資料. MAG = The papers of technical meeting on magnetics, IEE Japan, 電気学会, 2017(116) 7 - 12, 04 Aug. 2017 - Influence of Setting Position of H-coil on Measurement Accuracy of Magnetic Properties by Means of Single Sheet Tester
松原 稜; 髙橋 康人; 藤原 耕二; 石原 好之; 東 大地
電気学会研究会資料. MAG = The papers of technical meeting on magnetics, IEE Japan, 電気学会, 2017(116) 1 - 6, 04 Aug. 2017 - Investigation on Modeling Method of Magnetic Properties Considering Hysteresis and Excess Eddy Current Loss
蓑輪 直紀; 髙橋 康人; 藤原 耕二; 阿波根 明; 松尾 哲司
電気学会研究会資料. MAG = The papers of technical meeting on magnetics, IEE Japan, 電気学会, 2017(1) 43 - 48, 23 Feb. 2017 - Problems remained in high precision electromagnetic analyses(2)Investigation of improved simplified TP-EEC
徳増 正; 松下 真琴; 高橋 康人; 藤原 耕二; 若尾 真治
電気学会研究会資料. RM, 電気学会, 2017(16) 69 - 74, 19 Jan. 2017 - Effect of Steel Surface on Magnetic Properties of Electrical Steel Sheets and the Modeling
開道 力; 藤原 耕二; 高橋 康人; 松尾 哲司
電気学会研究会資料. RM, 電気学会, 2017(2) 7 - 12, 18 Jan. 2017 - Evaluation of Magnetic Properties of the Window-Shaped Core for Isotropic Vector Hysteresis Benchmarking
蓑輪 直紀; 髙橋 康人; 藤原 耕二
電気学会研究会資料. RM, 電気学会, 2017(2) 35 - 40, 18 Jan. 2017 - A Study of Power Balance for Electrical Machines in Magnetic Field Analysis
北尾 純士; 髙橋 康人; 藤原 耕二; 阿波根 明; 松尾 哲司; 大穀 晃裕
電気学会研究会資料. RM, 電気学会, 2017(2) 1 - 6, 18 Jan. 2017 - Time domain parallel finite-element method coupling with motion for transient motor starting analysis
Yasuhito Takahashi; Junji Kitao; Koji Fujiwara; Takeshi Iwashita; Hiroshi Nakashima
IEEJ Transactions on Power and Energy, Institute of Electrical Engineers of Japan, 137(3) 230 - 237, 2017 - Magnetic Behavior of Punched Edge of Non-Oriented Electrical Steel Sheets and the Modeling
開道 力; 藤原 耕二; 高橋 康人; 松尾 哲司; 宮田 健治; 田子 一農; 中野 智仁
電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 電子情報通信学会, 116(212) 1 - 6, 07 Sep. 2016 - Problems remained in high precision electromagnetic analyses : Review on convergence acceleration of time-periodic electromagnetic problems
徳増 正; 松下 真琴; 高橋 康人; 藤原 耕二; 若尾 真治
電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 電子情報通信学会, 116(212) 133 - 138, 07 Sep. 2016 - Fundamental Study on Magnetic Field Analysis by Using Local Expansion Edge Element Method
若山 裕綺; 内山 卓也; 若尾 真治; 徳増 正; 髙橋 康人; 藤原 耕二
電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 電子情報通信学会, 116(212) 121 - 125, 07 Sep. 2016 - Design of Window-shaped Core for Benchmark Model of Isotropic Vector Hysteresis
蓑輪 直紀; 髙橋 康人; 藤原 耕二
電気学会研究会資料. RM, 電気学会, 2016(103) 49 - 54, 07 Sep. 2016 - Magnetic Behavior of Punched Edge of Non-Oriented Electrical Steel Sheets and the Modeling
開道 力; 藤原 耕二; 高橋 康人; 松尾 哲司; 宮田 健治; 田子 一農; 中野 智仁
電気学会研究会資料. RM, 電気学会, 2016(103) 1 - 6, 07 Sep. 2016 - Fundamental Study on Magnetic Field Analysis by Using Local Expansion Edge Element Method
若山 裕綺; 内山 卓也; 若尾 真治; 徳増 正; 髙橋 康人; 藤原 耕二
電気学会研究会資料. RM, 電気学会, 2016(103) 121 - 125, 07 Sep. 2016 - Problems remained in high precision electromagnetic analyses : Review on convergence acceleration of time-periodic electromagnetic problems
徳増 正; 松下 真琴; 高橋 康人; 藤原 耕二; 若尾 真治
電気学会研究会資料. RM, 電気学会, 2016(103) 75 - 80, 07 Sep. 2016 - Magnetic Field Analysis of Interior Permanent Magnet Synchronous Motor in Finite Element Method Considering Hysteretic Property
北尾 純士; 髙橋 康人; 藤原 耕二; 阿波根 明; 松尾 哲司; 大穀 晃裕
電気学会研究会資料. RM, 電気学会, 2016(103) 37 - 42, 07 Sep. 2016 - Study on Correction Method of Magnetization Property for Magnetic Measurement of Ring Specimen
中井 紀裕; 中村 晃; 髙橋 康人; 藤原 耕二
電気学会研究会資料. RM, 電気学会, 2016(103) 31 - 36, 07 Sep. 2016 - Fundamental Investigation on Machine Performance of IEEJ Benchmark Model for Interior Permanent Magnet Synchronous Motor with Concentrated Winding
三和 大輝; 習田 祐作; 髙橋 康人; 藤原 耕二
電気学会研究会資料. RM, 電気学会, 2016(103) 253 - 258, 07 Sep. 2016 - Time Domain Parallel Finite-element Method Coupling with Motion for Transient Motor Starting Analysis
髙橋 康人; 北尾 純士; 藤原 耕二; 岩下 武史; 中島 浩
電気学会研究会資料. RM, 電気学会, 2016(103) 259 - 264, 07 Sep. 2016 - Problems remained in advanced design techniques using electromagnetic analyses(6)Basic Study on Improvement of convergence for coupled Electromagnetic and Circuit Problems
徳増 正; 長谷部 寿郎; 松下 真琴; 高橋 則雄; 髙橋 康人; 藤原 耕二
電気学会研究会資料. RM, 電気学会, 2016(18) 17 - 22, 21 Jan. 2016 - Convergence Acceleration of Time-Periodic Magnetic Field Analysis with Hysteresis Using Parallel TP-EEC Method
髙橋 康人; 北尾 純士; 藤原 耕二; 阿波根 明; 松尾 哲司
電気学会研究会資料. RM, 電気学会, 2016(1) 87 - 92, 20 Jan. 2016 - A study of representation of magnetization process of silicon steel sheets taking account of distribution of internal stress
伊藤 俊平; 美舩 健; 松尾 哲司; 開道 力; 高橋 康人; 藤原 耕二
電気学会研究会資料. RM, 電気学会, 2016(1) 13 - 17, 20 Jan. 2016 - Electrostatic Analysis by Boundary Integral Equation with True Charge Density and Double Layer Charge as Unknowns
笠 健悟; 若尾 真治; 髙橋 康人; 石橋 一久; Andjelic Zoran; 藤原 耕二
電気学会研究会資料. RM, 電気学会, 2016(1) 43 - 48, 20 Jan. 2016 - Validation of iron loss calculation methods for toroidal core
吉岡 卓哉; 柘植 竜也; 土井 智史; 藤原 耕二; 高橋 康人
電気学会研究会資料. RM, 電気学会, 2016(1) 31 - 36, 20 Jan. 2016 - Performance Evaluation of Mega Solar Photovoltaic Systems Connecting Photovoltaic Modules with Different Rated Value
岡 直孝; 髙橋 康人; 藤原 耕二
太陽/風力エネルギー講演論文集 = Proceedings of JSES/JWEA Joint Conference, 日本太陽エネルギー学会, 23 - 26, 2016 - A study on estimation method of magnetization distribution in a permanent magnet
中井 紀裕; 野田 和秀; 髙橋 康人; 藤原 耕二; 大橋 弘光
電気学会研究会資料. RM, 電気学会, 2015(126) 29 - 34, 29 Sep. 2015 - A Study on Application of Newton-Raphson Method to Time Harmonic Eddy-current Analysis Taking account of Nonlinear Magnetization Property
髙橋 康人; 美舩 健; 藤原 耕二
電気学会研究会資料. RM, 電気学会, 2015(126) 47 - 52, 29 Sep. 2015 - Problems remained in advanced design techniques using electromagnetic analyses(5)Basic Study on Parallel TP-EEC Method
徳増 正; 長谷部 寿郎; 松下 真琴; 高橋 則雄; 高橋 康人; 藤原 耕二
電気学会研究会資料. RM, 電気学会, 2015(114) 61 - 66, 28 Sep. 2015 - A study on Magnetostatic Shield Analysis by Double Layer Charge Formulation
笠 健悟; 吉岡 卓哉; 若尾 真治; 高橋 康人; 石橋 一久; 藤原 耕二
電気学会研究会資料. RM, 電気学会, 2015(25) 7 - 11, 06 Mar. 2015 - Simplified 3D Modeling for Skewed Rotor Slots with End-ring of Cage Induction Motor
山田 一輝; 髙橋 康人; 藤原 耕二
電気学会研究会資料. RM, 電気学会, 2015(25) 127 - 132, 06 Mar. 2015 - Parallel FEM Based on Domain Decomposition Method in Magnetic Field Analyses of Rotating Machines Using Nonconforming Mesh Connection Technique
髙橋 康人; 藤原 耕二; 岩下 武史; 中島 浩
電気学会研究会資料. RM, 電気学会, 2015(25) 93 - 98, 06 Mar. 2015 - Fundamental Investigation on Iron Loss Estimation Method for Hysteresis Loop with Minor Loops
竹田 よし美; 帶刀田 考弘; 髙橋 康人; 藤原 耕二
電気学会研究会資料. RM, 電気学会, 2015(1) 93 - 98, 05 Mar. 2015 - Improvement of Isotropic Vector Play Model under Rotational Flux Density Conditions
北尾 純士; 髙橋 康人; 藤原 耕二; 阿波根 明; 松尾 哲司; 大穀 晃裕
電気学会研究会資料. RM, 電気学会, 2015(1) 99 - 104, 05 Mar. 2015 - Problems remained in advanced design techniques using electromagnetic analyses(4)Basic Study on Parallel TP-EEC Method
徳増 正; 長谷部 寿郎; 松下 真琴; 高橋 則雄; 高橋 康人; 藤原 耕二
電気学会研究会資料. RM, 電気学会, 2015(1) 59 - 64, 05 Mar. 2015 - Study on Technology of Wireless Power Transfer to High Voltage Region with Data Transfer Function
ISHIZAKI Junki; KUBO Toshihiro; MATSUBARA Yoshio; TAKAHASHI Yasuhito; FUJIWARA Koji
Technical report of IEICE. Energy engineering in electronics and communications, The Institute of Electronics, Information and Communication Engineers, 114(429) 49 - 53, 29 Jan. 2015 - Problems remained in advanced design techniques using electromagnetic analyses(3)Study on Polyphase AC TP-EEC Method
徳増 正; 長谷部 寿郎; 松下 真琴; 高橋 則雄; 高橋 康人; 藤原 耕二
電気学会研究会資料. RM, 電気学会, 2014(96) 19 - 24, 26 Sep. 2014 - A Study on Modeling of Skewed Rotor Slots of Cage Induction Motors
髙橋 康人; 藤原 耕二
電気学会研究会資料. RM, 電気学会, 2014(96) 51 - 56, 26 Sep. 2014 - Parallelization of TP-EEC Method Based on Phase Conversion and Polyphase Time Periodic Condition
髙橋 康人; 徳増 正; 藤原 耕二; 岩下 武史; 中島 浩
電気学会研究会資料. RM, 電気学会, 2014(96) 13 - 18, 26 Sep. 2014 - Applying Boundary Element Methods to Multiply Connected Domains for Magnetostatic Field Problems
笠 健悟; 若尾 真治; 高橋 康人; 石橋 一久; 藤原 耕二
電気学会研究会資料. RM, 電気学会, 2014(80) 1 - 5, 25 Sep. 2014 - Fundamental Investigation for Improving Play Model
北尾 純士; 髙橋 康人; 藤原 耕二; 阿波根 明; 松尾 哲司; 大穀 晃裕
電気学会研究会資料. RM, 電気学会, 2014(80) 61 - 66, 25 Sep. 2014 - A study of Cauer Circuit Representations of AC Hysteretic Property of Silicon Steel Sheet Under PWM Excitation
宮崎 達也; 美舩 健; 松尾 哲司; 高橋 康人; 藤原 耕二; 進藤 裕司
電気学会研究会資料. RM, 電気学会, 2014(80) 79 - 83, 25 Sep. 2014 - Magnetic Field Analysis of Wound-Core Transformer Considering Deterioration of Magnetic Property in Corner Part
萩原 寛翔; 髙橋 康人; 藤原 耕二; 石原 好之; 増田 剛
電気学会研究会資料. RM, 電気学会, 2014(16) 27 - 32, 24 Jan. 2014 - Design of Magnetic Circuit for Downsizing, High Power and High Precision Electromagnetic Force Balance
住友 久人; 髙橋 康人; 藤原 耕二; 内藤 和文; 照沼 孝造; 池島 俊; 村井 大我
電気学会研究会資料. RM, 電気学会, 2014(16) 21 - 26, 24 Jan. 2014 - Problems remained in advanced design techniques using electromagnetic analyses(2)Study on simplified Poly-phase AC TP-EEC Method
徳増 正; 長谷部 寿郎; 松下 真琴; 高橋 則雄; 高橋 康人; 藤原 耕二
電気学会研究会資料. RM, 電気学会, 2014(1) 65 - 70, 23 Jan. 2014 - Analysis of DC-biased Characteristics of Reactor for Power Conditioner Considering Magnetic Hysteresis Property
樋口 真伍; 髙橋 康人; 藤原 耕二; 山田 直人; 西田 信博; 髙井 恭平
電気学会研究会資料. RM, 電気学会, 2014(1) 19 - 24, 23 Jan. 2014 - Accuracy Improvement of Boundary Element Methods for Magnetostatic Field Problems
吉岡 卓哉; 若尾 真治; 高橋 康人; Kielhorn Lars; 石橋 一久; 藤原 耕二
電気学会研究会資料. RM, 電気学会, 2014(1) 9 - 14, 23 Jan. 2014 - Effectiveness Evaluation of Degradation Factor Estimation Method for Crystalline Silicon PV Module Using Equivalent Circuit Analysis
木村 陽平; 髙橋 康人; 藤原 耕二
太陽/風力エネルギー講演論文集, 日本太陽エネルギー学会, 25 - 28, 2014 - Performance Evaluation of Time Domain Parallelized FEMs in Time-Periodic Nonlinear Magnetic Field Analyses of Electrical Machiens
Takahashi Yasuito; Tokumasu Tadashi; Fujiwara Koji; Iwashita Takeshi; Nakashima Hiroshi
The Proceedings of The Computational Mechanics Conference, The Japan Society of Mechanical Engineers, 2014(0) 114 - 116, 2014 - Calculation Method of Iron Loss Taking Account of Hysteretic Property
TAKEDA Yoshimi; TAKAHASHI Yasuhito; FUJIWARA Koji; AHAGON Akira; MATSUO Tetsuji
電気学会研究会資料. SA, 静止器研究会, 電気学会, 2013(75) 63 - 68, 26 Sep. 2013 - Problems remained in advanced design techniques using electromagnetic analyses -Advanced Techniques for Simlified TP-EEC Method-
TOKUMASU Tadashi; TAKAHASHI Yasuhito
電気学会研究会資料. SA, 静止器研究会, 電気学会, 2013(75) 19 - 24, 26 Sep. 2013 - Modeling of 2-D Magnetic Property Based on 1-D Measurements (Pt. 4)
HIGUCHI Shingo; TAKAHASHI Yasuhito; TOKUMASU Tadashi; FUJIWARA Koji
電気学会研究会資料. RM, 回転機研究会, 2013(1) 49 - 54, 24 Jan. 2013 - Three Dimensional Magnetic Field Analysis by Discontinuous Galerkin Method
FUCHINO Mizuki; MATSUBAYASHI Yu; WAKAO Shinji; TOKUMASU Tadashi; FUJITA Masashi; TAKAHASHI Yasuhito; FUJIWARA Koji
電気学会研究会資料. SA, 静止器研究会, 2013(1) 1 - 6, 24 Jan. 2013 - Study on Magnetic Field Analysis Taking Account of Hysteretic Property Using Play Model (Pt. 3)
KITAO Junji; TAKEDA Yoshimi; TAKAHASHI Yasuhito; FUJIWARA Koji; AHAGON Akira; MATSUO Tetsuji
電気学会研究会資料. SA, 静止器研究会, 2013(1) 43 - 48, 24 Jan. 2013 - Problems remained in advanced techniques of electromagnetic analyses (5)
TOKUMASU Tadashi; TAKAHASHI Yasuhito; FUJIWARA Koji
電気学会研究会資料. SA, 静止器研究会, 2013(1) 23 - 28, 24 Jan. 2013 - Development of High Efficiency Contactless Power Transfer System for Electric Vehicle
YOSHIKAWA Akitaka; TAKAHASHI Yasuhito; FUJIWARA Koji
IEICE technical report. Component parts and materials, The Institute of Electronics, Information and Communication Engineers, 112(397) 129 - 134, 24 Jan. 2013 - Study on Technology Suitable to Long Gap Wireless Power Transfer to High Voltage Region
GONDO Ryota; KUBO Toshihiro; MATSUBARA Yoshio; TAKAHASHI Yasuhito; FUJIWARA Koji
IEICE technical report. Component parts and materials, The Institute of Electronics, Information and Communication Engineers, 112(397) 123 - 128, 24 Jan. 2013 - Study on Interchangeability of Crystalline Silicon PV Modules : Influence of Connection of PV Modules with Different Rated Values on Output Power
堀江 康介; 髙橋 康人; 藤原 耕二
太陽/風力エネルギー講演論文集, 日本太陽エネルギー学会, 343 - 346, 2013 - Evaluation of Output Power Degradation Factor for Crystalline Silicon PV Cells by Using Image Diagnosis and Equivalent Circuit Model
木村 陽平; 髙橋 康人; 藤原 耕二
太陽/風力エネルギー講演論文集, 日本太陽エネルギー学会, 29 - 32, 2013 - Presumption of Lowering Factor of Power in Crystalline Silicon PV Modules Using Equivalent Circuit Model
林 健太郎; 髙橋 康人; 藤原 耕二
同志社大学理工学研究報告, 同志社大学理工学研究所, 53(4) 57 - 62, Jan. 2013 - Evaluation Method of Power Loss at Very Low Power Factor : Application to Inductor for Power Conditioner
HASHIMOTO Kazushige; TAKAHASHI Yasuhito; FUJIWARA Koji
電気学会研究会資料. MAG, マグネティックス研究会, 2012(146) 11 - 16, 06 Dec. 2012 - 710 Effectiveness of Play Model for Magnetic Hysteresis Phenomena
Kitao Junji; Hashimoto Kazushige; Takahashi Yasuhito; Fujiwara Koji
The Computational Mechanics Conference, The Japan Society of Mechanical Engineers, 2012(25) 333 - 334, 06 Oct. 2012 - Experiments on the growth of groups (Intelligence of Low-dimensional Topology)
Fujiwara Koji
RIMS Kokyuroku, Kyoto University, 1812 57 - 63, Oct. 2012 - Modeling of 2-D Magnetic Property Based on I -D Measurements (Pt. 3)
HIGUCHI Shingo; TAKAHASHI Yasuhito; TOKUMASU Tadashi; FUJIWARA Koji
電気学会研究会資料. RM, 回転機研究会, 2012(114) 77 - 82, 10 Sep. 2012 - Study on Magnetic Field Analysis Taking Account of Hysteretic Property Using Play Model (Pt. 2)
KITAO Junji; TAKAHASHI Yasuhito; FUJIWARA Koji; AHAGON Akira; MATSUO Tetsuji
電気学会研究会資料. RM, 回転機研究会, 2012(114) 1 - 6, 10 Sep. 2012 - Iron Loss Analysis of the Wound-Core Transformer Considering Core Joint Configuration
TAKAKURA Yoshifumi; TAKAHASHI Yasuhito; FUJIWARA Koji; ISHIHARA Yoshiyuki; MASUDA Tsuyoshi
電気学会研究会資料. RM, 回転機研究会, 2012(114) 83 - 88, 10 Sep. 2012 - Trial Production of Database on Magnetic Properties Aiming at Practical Hysteresis Analysis by Means of Play Model
AHAGON Akira; FUJIWARA Koji; TAKAHASHI Yasuhito; MATSUO Tetsuji
電気学会研究会資料. RM, 回転機研究会, 2012(114) 11 - 15, 10 Sep. 2012 - 関数型ベクトルヒステリシスモデルによる二次元磁化挙動
LEE Chahn; 宮田健治; 開道力; 松尾哲司; 美舩健; 藤原耕二; 高橋康人
電気学会静止器研究会資料, SA-12(79-98) 99 - 104, 10 Sep. 2012 - Investigation on Practical Implementation of ICCG Method and Proposal of Benchmarking Procedure to Evaluate Its Computation Speed
OKAMOTO Yoshifumi; TAKAHASHI Yasuhito; FUJIWARA Koji; AHAGON Akira; MIFUNE Takeshi; IWASHITA Takeshi
電気学会研究会資料. RM, 回転機研究会, 電気学会, 2012(94) 53 - 58, 10 Sep. 2012 - Magnetostatic Analysis by Magnetic Moment Method with Surface Loop Current as State Variable(
The 20th MAGDA Conference in Pacific Asia (MAGDA2011))
Kazuhisa ISHIBASHI; Zoran ANDJELIC; Yasuhito TAKAHASHI; Kenta TSUZAKI; Shinji WAKAO; Koji FUJIWARA; Yoshiyuki ISHIHARA
日本AEM学会誌 = Journal of the Japan Society of Applied Electromagnetics, 日本AEM学会, 20(2) 366 - 371, 10 Jun. 2012 - Investigation on the Effectiveness of Play Model by Using Hysteric Properties of Ring Core
HASHIMOTO Kazushige; KITAO Junji; TAKAHASHI Yasuhito; FUJIWARA Koji; AHAGON Akira; MATSUO Tetsuji
電気学会研究会資料. MAG, マグネティックス研究会, 2012(48) 15 - 20, 31 May 2012 - Estimation Method of Current Distribution by Measurement of Magnetic Near-field for EMC Evaluation of Power Circuit
MATSUOKA Makoto; TAKAHASHI Yasuhito; FUJIWARA Koji; ISHIHARA Yoshiyuki
IEICE technical report. Electromagnetic compatibility, The Institute of Electronics, Information and Communication Engineers, 111(420) 25 - 29, 27 Jan. 2012 - Study on Magnetic Field Analysis Taking Account of Hysteretic Property Using Play Model
北尾 純士; 橋本 和茂; 髙橋 康人; 藤原 耕二; 石原 好之; 阿波根 明; 松尾 哲司
電気学会研究会資料. RM, 電気学会, 2012(1) 89 - 94, 26 Jan. 2012 - Study on Discontinuous Galerkin Finite Element Method for Magnetic Field Analysis
SUGIMOTO Masato; WAKAO Shinji; TOKUMASU Tadashi; FUJITA Masashi; TAKAHASHI Yasuhito; FUJIWARA Koji; ISHIHARA Yoshiyuki
電気学会研究会資料. RM, 回転機研究会, 2012(1) 1 - 5, 26 Jan. 2012 - Generic Magnetostatic Analysis by Boundary Integral Equation Utilizing Duality of Loop Current
ISHIBASHI Kazuhisa; ANDJELIC Zoran; TAKAHASHI Yasuhito; FUJIWARA Koji; ISHIHARA Yoshiyuki; TSUZAKI Kenta; WAKAO Shinji
電気学会研究会資料. RM, 回転機研究会, 2012(1) 65 - 70, 26 Jan. 2012 - Verification of Computational Accuracy in Magnetic Field Analysis by Infinite Edge Element Method
TSUZAKI Kenta; TAWADA Yoshihiro; WAKAO Shinji; KAMEARI Akihisa; TOKUMASU Tadashi; TAKAHASHI Yasuhito; IGARASHI Hajime; FUJIWARA Koji; ISHIHARA Yoshiyuki
電気学会研究会資料. RM, 回転機研究会, 2012(1) 7 - 12, 26 Jan. 2012 - Time-Domain Parallel Finite-Element Method for Fast Magnetic Field Analysis of Induction Motors
TAKAHASHI Yasuhito; TOKUMASU Tadashi; FUJITA Masafumi; IWASHITA Takeshi; WAKAO Shinji; FUJIWARA Koji; ISHIHARA Yoshiyuki
電気学会研究会資料. RM, 回転機研究会, 電気学会, 2012(1) 31 - 36, 26 Jan. 2012 - Study of measurement method of magnetic property of magnetic materials for reactor
HASHIMOTO Kazushige; TAKAHASHI Yasuhito; FUJIWARA Koji; ISHIHARA Yoshiyuki
Technical report of IEICE. Energy engineering in electronics and communications, The Institute of Electronics, Information and Communication Engineers, 111(400) 91 - 96, 25 Jan. 2012 - Study on Characteristics of Contact-less Power Transfer System Using F-parameter Analysis
YOSHIKAWA Akitaka; TAKAHASHI Yasuhito; FUJIWARA Koji; ISHIHARA Yoshiyuki; SHIRAI Masayuki; INOUE Atsushi; KATANAYA Ikuya
Technical report of IEICE. Energy engineering in electronics and communications, The Institute of Electronics, Information and Communication Engineers, 111(400) 97 - 102, 25 Jan. 2012 - Experimental Verification of an Isolated Bidirectional DC-DC Converter
KATO Masayuki; TAKAHASHI Yasuhito; FUJIWARA Koji; ISHIHARA Yoshiyuki; SUGAHARA Kazuya; OGURA Masashi; MINOWA Yoshifumi; KURIO Nobuhiro
Technical report of IEICE. Energy engineering in electronics and communications, The Institute of Electronics, Information and Communication Engineers, 111(400) 81 - 86, 25 Jan. 2012 - Study on Interchangeability of PV Modules : Influence of Array Composition and Weather Conditions
堀江 康介; 髙橋 康人; 藤原 耕二
太陽/風力エネルギー講演論文集, 日本太陽エネルギー学会, 143 - 146, 2012 - Validity of Usefulness of Forecasting Irradiation by Using Cloud Image
南部 信司; 髙橋 康人; 藤原 耕二
太陽/風力エネルギー講演論文集, 日本太陽エネルギー学会, 99 - 102, 2012 - Individual Deterioration Evaluation of PV Cells in Crystalline Silicon PV Modules Based on Equivalent Circuit Analysis
林 健太郎; 髙橋 康人; 藤原 耕二
太陽/風力エネルギー講演論文集, 日本太陽エネルギー学会, 217 - 220, 2012 - Investigation on Improvement of Measurement Accuracy in Single Sheet Tester : Effect of Air Gap between Edge Face of Yoke and Specimen
ANDO Kunihiko; TAKAHASHI Yasuhito; FUJIWARA Koji; ISHIHARA Yoshiyuki
電気学会研究会資料. MAG, マグネティックス研究会, 2011(115) 55 - 60, 29 Nov. 2011 - Improvement of Two-Dimensional Single Sheet Tester for Magnetic Materials (Pt. 5) : Examination of detection range of magnetic flux density and magnetizing method
NAKAO Tomonori; TAKAHASHI Yasuhito; FUJIWARA Koji; ISHIHARA Yoshiyuki
電気学会研究会資料. MAG, マグネティックス研究会, 2011(129) 19 - 24, 29 Nov. 2011 - Magnetostatic Analysis by Magnetic Moment Method with Surface Loop Current as State Variable
ISHIBASHI K.; ANDJELIC Z.; TAKAHASHI Y.; FUJIWARA K.; ISHIHARA Y.; TSUZAKI K.; WAKAO S.
電気学会研究会資料. SA, 静止器研究会, 2011(46) 79 - 84, 25 Aug. 2011 - Effect of stress dependence of magnetic properties on operating characteristics of permanent magnet motors
KURITA Naoki; TAKAHASHI Yasuhito; FUJIWARA Koji; ISHIHARA Yoshiyuki
電気学会研究会資料. SA, 静止器研究会, 2011(63) 95 - 100, 25 Aug. 2011 - Verification of Functional Vector Hysteresis Model on one-dimensional Hysteresis
LEE Chahn; MIYATA Kenji; KAIDO Chikara; MASTUO Tetsuji; MIFUNE Takeshi; ISHIHARA Yoshiyuki; FUJIWARA Koji; TAKAHASHI Yasuhito
SA, 2011(63) 31 - 36, 25 Aug. 2011 - Modeling of 2-D Magnetic Property Based on 1-D Measurements
HIGUCHI Shingo; TAKAHASHI Yasuhito; TOKUMASU Tadashi; FUJIWARA Koji; ISHIHARA Yoshiyuki
電気学会研究会資料. SA, 静止器研究会, 2011(63) 25 - 30, 25 Aug. 2011 - Iron Loss Analysis in the Joint Part of the Wound-Core Transformer
TAKAKURA Yoshifumi; TAKAHASHI Yasuhito; FUJIWARA Koji; ISHIHARA Yoshiyuki; MASUDA Tsuyoshi
電気学会研究会資料. SA, 静止器研究会, 2011(63) 43 - 48, 25 Aug. 2011 - Automatic Determination of Acceleration Factor Based on Residual and Functional in Shifted ICCG Method
KITAO Junji; TAKAHASHI Yasuhito; FUJIWARA Koji; ISHIHARA Yoshiyuki; MIFUNE Takeshi; IWASHITA Takeshi
電気学会研究会資料. RM, 回転機研究会, 2011(59) 39 - 44, 25 Aug. 2011 - Accuracy Verification of a Single Sheet Tester
KIBE Toshiharu; TAKAHASHI Yasuhito; FUJIWARA Koji; ISHIHARA Yoshiyuki; KUTSUKAKE Akifumi; KIDO Yukihito; IKEDA Tetsu; KANADA Tsugunori; ENOKIZONO Masato
電気学会研究会資料. MAG, マグネティックス研究会, 2011(13) 1 - 6, 29 Jun. 2011 - Effect of the number of the rotor bars on the electromagnetic force in the induction motor(
19th MAGDA Conference)
TACHI Koji; TAKAHASHI Yasuhito; FUJIWARA Koji; ISHIHARA Yoshiyuki; KITAGAWA Wataru; INOUE Atsushi; KATANAYA Ikuya; Koji TACHI; Yasuhito TAKAHASHI; Koji FUJIWARA; Yoshiyuki ISHIHARA; Wataru KITAGAWA; Atsushi INOUE; Ikuya KATANAYA
Journal of the Japan Society of Applied Electromagnetics and Mechanics, 日本AEM学会, 19(2) 231 - 236, 10 Jun. 2011 - Influence of Switching Device Output Capacitance for Circuit Operation and Efficiency in Bidirectional DC-DC Converter
KATO Masayuki; TAKAHASHI Yasuhito; FUJIWARA Koji; ISHIHARA Yoshiyuki; OGURA Masashi; MINOWA Yoshifumi; KURIO Nobuhiro
IEICE technical report, The Institute of Electronics, Information and Communication Engineers, 110(393) 5 - 9, 20 Jan. 2011 - Evaluation of Stress-Dependent Magnetic Properties in Non-oriented Electrical Steel Sheets and Its Application to Magnetic Field Analysis of IPM Motor
KURITA Naoki; TAKAHASHI Yasuhito; FUJIWARA Koji; ISHIHARA Yoshiyuki
電気学会研究会資料. RM, 回転機研究会, 2011(14) 61 - 66, 20 Jan. 2011 - Some Treatments of Equivalent Volume Charges in Nonlinear Magnetostatic Analysis by BEM
ISHIBASHI K.; ANDJELIC Zoran; TAKAMATSU T.; WAKAO S.; TAKAHASHI Y.; FUJIWARA K.; ISHIHARA Y.
電気学会研究会資料. RM, 回転機研究会, 2011(1) 31 - 36, 20 Jan. 2011 - Advanced computational techniques for practical electric machine design
高橋 康人; 藤原 耕二; 石原 好之
The Science and engineering review of Doshisha University, 同志社大学理工学研究所, 51(4) 77 - 82, Jan. 2011 - Study on interchangeability of PV array connected with different modules: influence of difference of PCS
井関 和佳; 高橋 康人; 藤原 耕二
太陽/風力エネルギー講演論文集, 日本太陽エネルギー学会, 2011 21 - 24, 2011 - Presumption of lowering factor of power in crystalline silicon PV modules using field tests
林 健太郎; 高橋 康人; 藤原 耕二
Proceedings of JSES/JWEA JointConference, 2011, 日本太陽エネルギー学会, 2011 25 - 28, 2011 - Irradiation forecasting by using numerically predicted cloudiness and humidity in MSM data
中野 翔太; 高橋 康人; 藤原 耕二
太陽/風力エネルギー講演論文集, 日本太陽エネルギー学会, 2011 167 - 170, 2011 - A Trial Production of Single Sheet Tester for 100mm Square Specimen to Evaluate Magnetic Properties of both Rolling and Transverse Direction
ANDO Kunihiko; TAKAHASHI Yasuhito; FUJIWARA Koji; ISHIHARA Yoshiyuki
電気学会研究会資料. MAG, マグネティックス研究会, 2010(185) 11 - 16, 09 Dec. 2010 - Uniform Magnetic Field Analysis Using Subparametric Edge Based Finite Element Method
OKAMOTO Yoshifumi; TAKAHASHI Yasuhito; FUJIWARA Koji; AHAGON Akira; SATO Shuji
電気学会研究会資料. RM, 回転機研究会, 2010(85) 27 - 32, 28 Sep. 2010 - Magnetic Field at Vertex by Boundary Integral Equation Derived from Scalar Potential of Magnetic Double Layer
ISHIBASHI K.; ANDJELIC Zoran; WAKAO S.; TAKAMATSU T.; TAKAHASHI Y.; FUJIWARA K.; ISHIHARA Y.; FUJINO S.
電気学会研究会資料. RM, 回転機研究会, 2010(101) 13 - 18, 28 Sep. 2010 - Three-Dimensional Magnetic Field Analysis by Using Infinite Edge Element
TAMITANI Satoshi; TAKAMATSU Tomoaki; WAKAO Shinji; KAMEARI Akihisa; TAKAHASHI Yasuhito; FUJIWARA Koji; ISHIHARA Yoshiyuki
電気学会研究会資料. RM, 回転機研究会, 2010(85) 39 - 44, 28 Sep. 2010 - Comparison between Time Differential Correction Method and Time-Periodic Explicit Error Correction Method in Transient Magnetic Analysis of Electric Machines
TAKAHASHI Yasuhito; TOKUMASU Tadashi; FUJITA Masafumi; WAKAO Shinji; FUJIWARA Koji; ISHIHARA Yoshiyuki
電気学会研究会資料. RM, 回転機研究会, 2010(85) 83 - 88, 28 Sep. 2010 - A basic study on the modeling of magnetic properties of step lap joints in wound core transformer
NAKAMURA Hiroshi; TAKAHASHI Yasuhito; FUJIWARA Koji; ISHIHARA Yoshiyuki; MASUDA Tsuyoshi
電気学会研究会資料. RM, 回転機研究会, 2010(101) 65 - 70, 28 Sep. 2010 - Magnetostriction Properties of Powder Magnetic Core under the DC-biased
KUROSE Ryuya; TAKAHASHI Yasuhito; FUJIWARA Koji; ISHIHARA Yoshiyuki; YAMADA Yukinori
電気学会研究会資料. MAG, マグネティックス研究会, 2010(99) 15 - 19, 26 Aug. 2010 - Numerical simulation of electromagnetic fields in electric machines
藤原 耕二; 岡本 吉史; 石原 好之
The Science and engineering review of Doshisha University, 同志社大学理工学研究所, 50(4) 78 - 83, Jan. 2010 - Study on forecasting irradiation by using numerical prediction data
中野 翔太; 高橋 康人; 藤原 耕二
太陽/風力エネルギー講演論文集, 日本太陽エネルギー学会, 2010 385 - 388, 2010 - Degradation study of crystalline silicon PV modules using field tests
高橋 智晃; 高橋 康人; 藤原 耕二
太陽/風力エネルギー講演論文集, 日本太陽エネルギー学会, 2010 275 - 278, 2010 - A study on power characteristics of PV array connected with different modules: by simulation
井関 和佳; 高橋 康人; 藤原 耕二
太陽/風力エネルギー講演論文集, 日本太陽エネルギー学会, 2010 285 - 288, 2010 - Folded IC preconditioning in quasi-static field analysis taking account of both tree-cotree and φ = 0 gauge conditions
Yasuhito Takahashi; Takeshi Mifune; Takeshi Iwashita; Koji Fujiwara; Yoshiyuki Ishihara
Digests of the 2010 14th Biennial IEEE Conference on Electromagnetic Field Computation, CEFC 2010, 2010 - Outline of Research Center of Applied Electromagnetic Energy
石原 好之; 藤原 耕二
The Science and engineering review of Doshisha University, 同志社大学理工学研究所, 49(4) 102 - 107, Jan. 2009 - Proposal for benchmark model of laminated iron core and the large-scale and highly accurate magnetic field analysis
Yasuhito Takahashi; Shinji Wakao; Koji Fujiwara; Hiroyuki Kaimori; Akihisa Kameari
IEEJ Transactions on Power and Energy, 127, 03 Sep. 2007 - The Dielectric Heating Analysis with Rotational Motion of Stirrer Fan by Using Finite Element Method
OKAMOTO Yoshifumi; HIMENO Ryutaro; USHIDA Kiminori; AHAGON Akira; FUJIWARA Koji
電気学会研究会資料. SA, 静止器研究会, 2007(17) 7 - 12, 26 Jan. 2007 - A Method of Determination of the Imposed Current Density in a Winding
FUJIWARA Koji
電気学会研究会資料. SA, 静止器研究会, 2006(58) 13 - 18, 24 Aug. 2006 - Fundamental Investigation on AC Magnetic Loss of Nd-Fe-B Sintered Magnet
FUJIWARA Koji
電気学会研究会資料. MAG, マグネティックス研究会, 2005(103) 35 - 39, 24 Nov. 2005 - Investigations on Magnetization Curve Suitable for Magnetic Field Analysis and Loss Separation
FUJIWARA Koji
電気学会研究会資料. SA, 静止器研究会, 2005(20) 25 - 30, 28 Jan. 2005 - Useful Formulas of Analytical Integration in Electromagnetic Field Computations (Part 6)
WAKAO Shinji; FUJIWARA Koji; TOKUMASU Tadashi; KAMEARI Akihisa
電気学会研究会資料. SA, 静止器研究会, 2005(1) 83 - 89, 27 Jan. 2005 - Magnetic Field Analysis Using Homogenization Method
MUTO Hiroyuki; FUJISHIMA Yasushi; WAKAO Shinji; FUJIWARA Koji
電気学会研究会資料. SA, 静止器研究会, 2005(1) 91 - 97, 27 Jan. 2005 - A Proposal on Approximation Method for Magnetization Property
FUJIWARA Koji
電気学会研究会資料. RM, 回転機研究会, 2004(83) 57 - 62, 09 Jul. 2004 - Useful Formulas of Analytical Integration in Electromagnetic Field Computations (Part 4)
WAKAO Shinji; FUJIWARA Koji; NOGUCHI So; MATSUO Tetsuji; KAMEARI Akihisa
電気学会研究会資料. SA, 静止器研究会, 2004(1) 1 - 6, 26 Jan. 2004 - The Newton-Raphson Method Accelerated by Using a Line Search : Comparison between Energy Functional and Residual Minimization
FUJIWARA Koji; OKAMOTO Yoshifumi; KAMEARI Akihisa; AHAGON Akira
電気学会研究会資料. SA, 静止器研究会, 2004(1) 31 - 36, 26 Jan. 2004 - Useful Formulas of Analytical Integration in Electromagnetic Field Computations (Part 1)
WAKAO Shinji; IGARASHI Hajime; FUJIWARA Koji; KAMEARI Akihisa
電気学会研究会資料. RM, 回転機研究会, 2002(58) 37 - 42, 02 Sep. 2002 - Practical Aspects of Approximation Methods for Magnetization Characteristics
FUJIWARA Koji
日本応用磁気学会研究会資料, 104 53 - 58, 17 Mar. 1998 - Investigations on Shape Functions of Edge Elements
AHAGON Akira; FUJIWARA Koji
電気学会研究会資料. SA, 静止器研究会, 1997(11) 7 - 12, 05 Aug. 1997 - Summary of results for benchmark problem 13 (3-d nonlinear magnetostatic model)
Takavoshi Nakata; Koji Fujiwara
COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, 11(3) 345 - 369, 01 Mar. 1992, Book review - Summary of results for benchmark problem 10 (steel plates around a coil)
Takayoshi Nakata; Norio Takahashi; Koji Fujiwara
COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, 11(3) 335 - 344, 01 Mar. 1992, Book review - Results for benchmark problem 10 (steel plates around a coil)
Takayoshi Nakata; Koji Fujiwara
COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, 9(3) 181 - 190, 01 Mar. 1990, Book review - Results for benchmark problem 7 (asymmetrical conductor with a hole)
Koji Fujiwara; Takayoshi Nakata
COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, 9(3) 137 - 154, 01 Mar. 1990, Book review
Research Projects
- 磁気ヒステリシスを定量化した，加速器用電磁石の高速かつ高精度な制御方法の研究
菅原 賢悟; 石 禎浩; 藤原 耕二; 中村 健二; 羽根 吉紀
粒子加速器による磁場制御の精度をさらに向上させるためには、これまで粒子加速器分野で研究されてこなかった磁気ヒステリシスや磁気残効をモデル化することが必要である。本論文では、モデル化に必要な実験データを取得するため、電磁石の磁場測定環境の構築及び磁場測定を行い，測定した基礎データの分析を行った．測定結果より，磁気余効の時定数より十分に長い待機時間を設けた場合，渦電流などによる磁場の遅れが増加するという現象と真逆の現象を確認した． この現象の原因については今後の研究で明らかにしていく必要がある．また，電気機器の分野において提案されたヒステリシスモデリング手法は，そのままの形では加速器の分野に適用できないことを明らかにした．したがって，これらの現象を考慮した新たなモデリング手法の確立も必要である．, 日本学術振興会, 科学研究費助成事業, 2020/04 -2023/03, 基盤研究(C), 近畿大学 - Development of physical and phenomenological models of stress-dependent vector magnetic properties of core materials for electric machins
Matsuo Tetsuji
[1. Development of measuring technique of stress-dependent vector magnetic property] A pair of piezoelectric films is attached to a circular sample of silicon steel sheet in the rotational single sheet tester, wherein the film shrinks to exert compressive stress on the sheet. [2. Improvements of domain model] The magnetostatic computation is simplified for a fast magnetization analysis under mechanical stress without loss of prediction accuracy. Using the identification method of vector play model, the pinning-field distribution in the domain model is identified from measured BH loops under the stress-free condition. [3. Study of equivalent stress theory] Equivalent stress models are numerically tested to predict the stress-dependent magnetic property from a unidirectional measurement., Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, 2017/04 -2021/03, Grant-in-Aid for Scientific Research (C), Kyoto University - Study on a multi-physics model of magnetic properties of iron-core material taking into account mechanical stress
Matsuo Tetsuji; TAKAHASHI Yasuhito
A multi-physics model of iron-core material is developed to take into account the effect of mechanical stress on the magnetic properties. Stress dependent magnetic properties and vectorial magnetic and magnetostrictive properties of silicon steels were measured. An assembled domain structure model (ADSM) is developed using the 6-domain simplified domain structure model as unit cell. The ADSM is a physical model that can predict the magnetic properties from basic material parameters such as the anisotropy constant and the magnetostriction constant. The deterioration of magnetic property of non-oriented silicon steel sheet is reconstructed by the ADSM. Assuming a distribution of pinning field, the ADSM predicts the iron-loss increase due to the applied compressive stress, which agrees with measured loss property depending on the stress. A partially-implicit method is developed to accelerate the energy minimization in the ADSM., Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, 2014/04 -2017/03, Grant-in-Aid for Scientific Research (C), Kyoto University - RESEARCH FOR INTERNATIONAL STANDARD ON MEASUREMENT METHOD OF MAGNETIC PROPERTIES BY MEANS OF A SINGLE SHEET TESTER EQUIPPED WITH H-COIL
FUJIWARA Koji; OKAMOTO Yoshifumi
The magnetic properties of electrical steel sheets used for iron cores of electric machines such as transformers and motors are evaluated by means of a testing method based on a single sheet tester(SST) equipped with Japanese proposed H-coil technique for measuring the magnetic field strength. In this research, factors affecting the measurement accuracy of the testing method are examined with the aim of the international standardization. It is clarified that flatness of end surface contacting a specimen is considerably sensitive to the measurement accuracy. Its effect is remarkable, especially in an SST for 500 mm-width specimen proposed by the International Electrotechnical Commission., Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, 2008 -2011, Grant-in-Aid for Scientific Research (B), Doshisha University - Research work of reconfigurable millimeter wave antenna
KOTERA Hidetoshi; KANNO Isaku; SUZIKI Takaaki; FUJIWARA Kohji
In this research work, we have tried to realize a reconfigurable millimeter wave antenna. To realize the reconfigurable antenna, as a first step, we developed two types antenna mechanism. One is a kind of micro-strip line antenna in which the electric current is controlled to be delay for the grand line or neighboring lines. Another type is a novel mechanism by actuating conductor elements which is arranged in matrix manner in two layers that is separated by dielectric material. To design the antennas, we calculated the characteristics of wave trajectory in the air from the antenna by FDTD simulation and finite element simulation. The optimization technique was also used to define their optimum shape. The designed antenna was fabricated by use of the bulk micromachining with silicon substrate and thin metal film and by use of soft micromachining with PDMS and SU8. We measured the wave propagation from the fabricated antenna in 50GHz range, the characteristic of the antenna agreed well with the calculated results. To simplify the reconfigurable anntena in the field of millimeter wave, we focused on the dependency of the permeability of piezoelectric material, we designed new heater driven antenna using both CIP calculation and FDTD calculation. The designed antennas were fabricated using MEMS process. The fabricated antennas were tested but the emition properties were not efficiency because of the patterning accuracy and heat-insulated structure. To drive the antenna we designed and fabricated two types RF-MEMS switch. One is a cantilever type, and another type is a X-Bar type. Both type switches are driven by the PZT thin film deposited on Si substrate. In this research work, we prove that the designed mechanism and structure for the antenna is feasible for reconfigurable micro antenna. We can conclude that our research work is worth for realize new antenna and switch in the field of millimeter wave or more high frequency field., Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, 2003 -2006, Grant-in-Aid for Scientific Research (A), KYOTO UNIVERSITY - STUDY ON MAGNETIC FIELD ANALYSIS FOR DEVELOPING HIGHLY EFFICIENCY MOTORS CONSIDERING RESIDUAL STRESS AND ROTATING FIELD
TAKAHASHI Norio; FUJIWARA Koji; MIYAGI Daisuke
The magnetic characteristics when the stress is impressed and under rotating flux are measured using single sheet testers(SST). The method for applying these data to the analysis of magnetic field of motor is investigated. The results obtained are summarized as follows : 1.Establishment of Measuring System and Examination of Measurement Accuracy A digital measuring system is established, and the effect of the phase error and characteristics of gain on the measurement accuracy is examined. 2.Measurement of Magnetic Characteristics Under Stress Impressed Condition and Rotating Flux The magnetic characteristics when until about 70 Mpa is impressed are measured. The iron losses due to rotating flux, under various combinations of long and short axes of ellipse and harmonic components which are observed in the actual motors, are measured and the data base for the numerical analysis is constructed. 3.Measurement of Magnetic Characteristics Under Shrink Fitting The microscopic magnetic characteristics of ring core under shrink fitting of aluminum ring are measured using a special H coil and a modified probe method. The local magnetic characteristics are examined. 4.Effect of Temperature on Magnetic Characteristics of Steel The change of magnetic characteristics with the temperature is measured by setting SST in an oven. It is shown that the iron loss is reduced with the temperature, and the rate of decrease of hysteresis loss of low grade steel is remarkable. 5.Analysis of Iron Loss of Verification Model of Motor and Experimental Investigation The iron loss of verification motor model is analyzed using FEM considering the residual stress and magnetic property under rotating field. The problems of the analysis of iron loss is examined by comparing with the measured values., Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, 2002 -2004, Grant-in-Aid for Scientific Research (B), OKAYAMA UNIVERSITY - Vector Magnetic Properties Oriented to Magnetic Field Analysis
FUJIWARA Koji; TAKAHASHI Norio
Numerical simulation of magnetic fields requires a proper material modeling as well as a robust method of discretization of governing equations. Only a robust discretization is not enough to get higher accuracy and to improve design strategy. Recently, the material modeling receives large engineering attention. In this project, magnetic anisotropy (vector magnetic property) of electrical steel sheet, which is used as a material for principal magnetic path in electrical machine, is discussed. A standard method of measurement by means of a double-excitation type of single sheet tester is investigated and a modeling method for anisotropy is developed based on the finite element formulation. Then it is applied to the analysis of typical electrical machines for verification. The contents discussed are as follows. (1)Construction of a measuring system, and examination of measurement accuracy and its improvement, (2)Measurements of vector magnetic properties of various electrical steel sheets, (3)Development of an approximation method of vector magnetic property, its verification by using numerical simulation method, and its stabilization and speedup, (4)Application to three-phase transformer core and interior permanent magnet motor. Regarding to a method of measurement, magnetization properties up to 2 T can be measured for various kinds of electrical steel sheets with different degree of anisotropy Reproducibility of the measurement is within about ±3%, which is similar to that for ordinary 1-D measurements. Therefore, the proposed method of measurement seems to be fairly useful. Regarding to numerical simulation, a method of modeling anisotropy using normal magnetization curves are established. Its stability for nonlinear iterative analysis is nearly equivalent to ordinary calculations without taking account of anisotropy because of the introduction of a line search technique. Robustness of the method is verified by applying it to the analysis of typical electrical machines using recently developed cube-textured electrical sheets., Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, 2001 -2003, Grant-in-Aid for Scientific Research (B), Okayama University - ADVANCED METHOD FOR ANALYZING MAGNETIC FIELD AND APPLICATION
TAKAHASHI Norio; FUJIWARA Koji
In order to utilize the magnetic field analysis in the practical design, methods for improving the quality of magnetic field analysis using the finite element method and the integral equation method are investigated, and the application to the design of electrical and electronic machines are examined. The results obtained are summarized as follows : 1. Improvement of Quality of Magnetic Field Analysis The edge - based finite element software, with high accuracy and short CPU time has been developed. The accuracy of the integral equation method is improved and the CPU time is reduced by examining the treatment of iron edge and the selection of unknown variable. 2. Verification of Magnetic Field Analysis 3-D eddy currents, electromagnetic forces and iron losses of standard models of TEAM International Workshop are compared, and the problems in the numerical analysis are examined. It is pointed out that the hysteresis loss in the steel plate cannot be neglected in some cases due to the skin effect. 3. Problems in Applying to Design of Electrical Machines It is shown that the nonconforming mesh is useful in treating the rotation, and the de steady state analysis method is effective in the combined analysis with motion. 4. Measurement of Magnetic Properties at High Flux Density and Low Frequency The operating flux density of recent machines is sometimes up to 2T in order to design compact and highly - efficient machines. Then, the behavior of magnetic properties under rotating flux at high flux density is clarified by utilizing a newly - developed closed magnetic path type of single sheet tester with double excitations., Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, 1999 -2000, Grant-in-Aid for Scientific Research (B)., OKAYAMA UNIVERSITY - 超低周波から商用周波帯域における磁性材料の磁気特性測定法の高精度化に関する研究
藤原 耕二
本研究の目的は,ディタル方式の単板磁気特性試験法により,電磁鋼板の超低周波から商用周波帯域における磁気特性の高精度測定法を確立することである.本年度の成果を要約すれば,以下のようになる. 1. 開路型単板磁気試験器を用いたディジタル磁気特性測定システムにおける波形制御法 電気機器で発生する騒音の一因である磁歪を測定する場合,ヨークを有する閉磁路型単板磁気試験器(SST)では,試料とヨーク間に働く電磁力が問題になる.そこで,開磁路型SSTを製作したが,端部における磁界の低下を補正するための補助巻線が必要であり,主巻線のみの閉磁路SST用の波形制御法は不十分であった.今回,主および補助巻線の両方を制御することにより,閉磁路SST用制御法と同程度の制御特性が実現できた.これによって,従来困難であったアモルファス金属薄帯の磁歪測定力呵能になった. 2. 位相ずれが鉄損測定精度に与える影響 種々の測定システムで高磁束密度領域の鉄損を測定したところ,定性的に妥当な傾向が得られない場合があり,主にHコイルおよびA/D変換器が原因であることが明らかになった.特に,超低周波用Hコイルでは,S/N比を向上させるために,多層巻きにして巻数を多くしており,その場合には線間の静電容量により位相ずれが相当大きくなる.そこで,位相ずれの周波数特性をあらかじめ測定し,ソフトウェア的に補正する方法を検討した結果,妥当な精度が得られることが明らかになった. 3. 地磁気による直流偏磁の低減法 SSTのみでは,試料の幅方向を地磁気の方向に一致させれば,試料の反磁界により,地磁気の低減が可能であることが明らかになった.しかしながら,磁気特性と機械的特性の相関を検討するために,SSTと引張試験機を用いた装置を試作したところ,引張試験機の支柱等が磁化されているために,上記知見が通用しないことが判明した.そこで,引張試験機の消磁を行うとともに,SSTと引張試験機を一体として回転することにより,パーマロイのような高透磁率材料においても,偏磁の影響がない磁気特性測定が可能になった., 日本学術振興会, 科学研究費助成事業, 1997 -1998, 奨励研究(A), 岡山大学 - Analysis of Iron Loss in Magnetic Material using Time-Periodic Finite Element Method Taking Account of Hysteresis and Eddy Current
TAKAHASHI Norio; MURAMATSU Kazuhiro; FUJIWARA Koji
3-D time-periodic finite element method and modeling technique of hysteresis loop are developed in order to establish 3-D nonlinear magnetic field analysis method for the accurate analysis of iron loss in electric machines. Moreover, the flux and iron loss in model core are also analyzed and measured. 1. Development of 3-D Time-Periodic Finite Element Method The time-periodic method which can directly obtain the ac steady state phenomenon is introduced to 3-D finite element method using edge element. Then, a code for solving 3-D ac steady state magnetic field within a practical CPU time can be developed. 2. Development of Modeling Technique of Hysteresis Loop The modified Preisach model using the inverse distribution function is conceived so that the magnetic field strength can be directly obtained from the given flux density. By using this method, the CPT time can be considerably reducedin the magnetic field analysis taking account of hysteresis. 3.Measurement of Hysteresis Loop As the dc hysteresis loop is necessary in magnetic field analysis, the magnetic measurement method under the extremely low frequency less than 0.01Hz is developed by utilizing the digital integration of the output of an H coil. 4. Analysis of Flux and Iron Loss of Core and Measurements The flux distribution in model core is analyzed, and the method for calculating the hysteresis and eddy current losses from the calculated hysteresis loop is investigated. The analyzed results of flux and iron loss are compared with measured ones., Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, 1997 -1998, Grant-in-Aid for Scientific Research (C), Okayama University - Development of Design Method of Energy Efficient Machines
TAKAHASHI Norio; MURAMATSU Kazuhiro; FUJIWARA Kouji; NAFLASKI Andrew; JAIN Lakhmi; GOL Ozdemir
In order to increase the efficiency of electric machines, the technique for analyzing rotating machines, optimal design method, measuring technique of magnetic characteristics with high accuracy are developed. The optimization technique of permanent-magnet rotating machine is also investigated. The results obtained can be summarized as follows ; 1. Development of Method for Analyzing Magnetic Field Considering Rotation and Distorted Waveform of Power Source In order to analyze the rotating machine fed by inverter, 3-D finite element method (FEM) which can take account of rotation and distorted waveform is developed. 2. Development of Optimal Design Method of Electric Machines Problems in the optimal design of rotating machines using 3-D FEM and Rosenbrock's method are examined. 3. Development of Measuring Technique of Magnetic Characteristics and Measurements The magnetic characteristics which are used in magnetic field analysis are measured up to high flux density by investigating the controlling technique of waveform and by developing the new-type measuring apparatus of 2-D magnetic characteristics. 4. Optimal Design of Permanent Magnet Rotating Machine The permanent rotating machine is optimized using 3-D FEM and optimization method. It is shown that the torque can be increased by 40%., Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, 1997 -1998, Grant-in-Aid for international Scientific Research, Okayama University - Development of Methods for Measuring Magnetic Characteristics of Strong Magnet
TAKAHASHI Norio; TAKABAYASHI Hirofumi; OHASHI Ken; MURAMATSU Kazuhiro; FUJIWARA Koji
The basic investigations for preparing the draft about IEC standard method of for measuring magnetic characteristic of strong magnet are carried out. The results obtained can be summarized as follows : 1. Development of Method for Analyzing Magnetic Field in Non-Oriented Materials Taking into Account Hysteresis Characteristics In order to calculate demagnetizing factor for permanent magnet, the method for analyzing magnetic field in non-oriented materials taking into account hysteresischaracteristics is developed. In this method, M-B loop is used as magnetic characteristics and the direction of magnetization is assumed to be the same with that of flux density. 2. Development of Method for Analyzing Magnetic Field in Electric Machine Magnetized by Discharging Current of Capacitors If the pulse width of the open magnetic circuit method is small, the error of measured magnetic field strength due to the opposing magnetic field produced by he eddy current is not negligible. In order to investigate the effect of the pulse width on the accuracy, the finite element method, in which the magnetizing current is unknown, is developed. The validity of the method is verified by comparing the calculated results with measured ones. 3. Factors Affecting Accuracy of Measurement (1) Shape of specimen The optimum shape of specimen is that the height of magnet is the same with the diameter from a standpoint of constant demagnetizing factor. (2) Magnetic characteristics of specimen The variation of demagnetizing factor of Nd-Fe-B magnet is larger than that of Sm-Co magnet near the coercive force. (3) Manufacturing deterioratration The effects of manufacturing deterioratin of side surface of specimen on the demagnetizing factor is larger than that of edge surface. This effects is large when the specimen is long. (4) Eddy current The change of magnetic field dB/dt produced by the pulse magnet should be less than 80T/ms in order to obtain 3% accuracy., Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, 1995 -1996, Grant-in-Aid for Scientific Research (B), Okayama University - Investigation of Quenching Phenomena at the Joint between AC Superconducting Cable and Normal Conducting Plate and Optimization of Joint
TAKAHASHI Norio; FUJIWARA Koji
The quenching phenomena at the joint between ac superconducting cable and normal conducting plate is investigated and its joint is optimized by carrying out 3-D numerical analysis and experiments. The results obtained can be summarized as follows : 1.Development for Analyzing 3-D Current Distribution at the Joint between AC Superconducting Cable nnd Normal Conducting Plate A new method for analyzing 3-D current distribution in the joint having such remarkable skin effect is developed by calculating impressed current and eddy current separately. 2.Measurement of Current Distribution at Joint under Commercial Frequency The current distribution on the surface of the copper plate is measured using the modified probe method which is developed by us. As the output signal of the probe is very small (mu V order), homodyne method is used. The reason why the quenching occurs at the commercial frequency is also clarified by experiment. 3.Optimization of Joint The optimal joint is investigated by examining the effects of the shape and dimension of joint on the concentration of current. 4.Experimental Verification The optimal joint is produced, and the maximum current which flows in the optimal joint without quenching is clarified by experiment., Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, 1994 -1995, Grant-in-Aid for General Scientific Research (C), Okayama University - Development of Single Sheet Tester for Measuring Magnetic Characteristics of Amorphous Magnetic Metals
NAKATA Takayoshi; YAGO Katsuji; NOZAWA Tadao; FUJIWARA Koji; TAKAHASHI Norio
In order to propose a draft of "Standard measuring method of magnetic characteristics of amorphous metal for power apparatus" for the IEC,effects of geomagnetism and residual magnetism, etc.on measured magnetic characteristics were investigated. The results obtained can be summarized as follows : 1.Effect of Geomagnetism on Measured Magnetic Characteristics The results measured inside and outside a magnetic shielding room were compared with each other. It was shown that if the angle between the longitudinal direction of the specimen and the direction of geomagnetism is perpendicular, the performance of the double yoke type of single sheet tester outside the magnetic shielding room is acceptable. 2.Effect of Residual Magnetism in the Yoke of Measured Magnetic Characteristics It was shown that the effect residual magnetism in the horizontal yoke type of the single sheet tester is larger than that in the vertical one. 3.Effect of Impedance of Winding on Distortion of Flux Waveform The effects of the impedances of the primary winding and the mutual inductor for air-flux compensation of the single sheet tester on the distortion of the flux waveform were investigated. It was shown that the layrs which compose the winding should be connected in series. 4.Improvement of Waveform Controlling Method In order to reduce the number of iterations of digital feedbacks, a new controlling method for the waveform which estimates the waveform of the applied voltage using the equivalent circuit of the single sheet tester was developed. The time for measuring magnetic characteristics has been considerably reduced by using this method. 5.Intercomparison of Measurements A Japanese intercomparison of measurements of the magnetic characteristics for amorphous magnetic material was carried out. The results of the institutes have been considerably different and the counter plan is being investigated now. Now, it is being tried to improve the existent JIS standard by the above investigation. The intercomparison between various countries is prepared in order to propose a new IEC standard., Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, 1994 -1995, Grant-in-Aid for Developmental Scientific Research (B), Okayama University - Development of Methods for Analyzing Eddy Currents in Moving Conductors and Verification
NAKATA Takayoshi; FUJIWARA Koji; TAKAHASHI Norio
The methods for analyzing 3-D eddy currents in moving conductors are developed and the various methods are compared with each other. The acceleration of the ICCG method which is used as solver for large linear equation systems is also investigated. The results obtained can be summarized as follows : 1.Development of Methods for Analyzing Eddy Currents in Moving Conductors The methods for analyzing magnetic circuits with moving conductors are systematically classified and the preferable method for each circuit is shown. The treatment of eddy current term using moving and fixed coordinate systems are investigated and the software is developed. 2.Comparison of Various Methods The methods using moving and fixed coordinate systems are compared with each other from the standpoints of accuracy, memory requirement and CPU time by using a verification model. The results obtained can be described as follows : (1) In the transient analysis, the moving coordinate system is superior from the standpoints of accuracy, computer storage and CPU time. (2) In the dc and ac steady state analysis for large Peclet numbers, spurious oscillations occur when using a fixed coordinate system with ordinary Galerkin finite element method. The solution using a moving coordinate system, however, can be obtained with a high reliability. The optimal value of the time step for the moving coordinate system is also clarified. 3.Acceleration of Solving Large Linear Equation Systems The algorithm for the calculation of the distribution of non-zero entries in ICCG method is improved in order to accelerate the computation. It is shown that the convergence characteristics of the ICCG method for the analysis using magnetic vector potential and edge elements can be considerably massively improved by introducing the electric scalar potential., Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, 1994 -1995, Grant-in-Aid for General Scientific Research (B), Okayama University - Efficient Use of Steels and Development of Low Loss Machines
NAKATA Takayoshi; LING P.c.y; MEYDAN T; BASAK A.; MOSES A.j; MURAMATSU Kazuhiro; FUJIWARA Koji; TAKAHASHI Norio
A method for calculating flux distrbutions in anisotropic materials and measuring technique of magnetic characteristics are investigated for the purpose of the development of low loss machines and making the efficient use of steel. The results obtained can be summarized as follows : 1. Development of Softwares for Analysis of Flux Distributions in Anisotropic Materials (1) The functions Bx=fx (Hx, Hy), By=fy (Hx, Hy) are used for the magnetic characteristics of anisotropic materials. (2) The convergence characteristics of nonlinear iteration and matrix solver are improved by using relaxation and over relaxation factors, respectively. (3) The 3-D time periodic finite element method is developed for nonlinear steady state analysis. 2. Development of Measurement Method for Magnetic Characteristics in Anisotropic Materials (1) Double yokes is used for measuring the magnetic characteristics in arbitrary directions of anisotropic materials. (2) The effect of the waveforms of B and H on the measured B-H curves is investigated. 3. Development of Method for Estimating Iron Losses The hybrid method which couples the calculation and the measurement is developed for loss estimation. 4. Verification of Software The verification model is proposed, and results calculated using the developed method are in good agreement with measured results. 5. Applications The developed analysis and measurement method are applied for the investigation of flux distribution in a reactor. The weight of the reactor is decreased while the efficiency is increased., Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, 1994 -1995, Grant-in-Aid for international Scientific Research, Okayama University - Development of 3-D Numerical Analysis and Applications
NAKATA Takayoshi; REYNE G.; MEUNIER G.; COULOMB J.l.; SABONNADIERE J.c.; FUJIWARA Koji; TAKAHASHI Norio
Various methods for analyzing 3-D magnetic fields are developed, and calculation methods of force and torque are verified by comparing with measurement. The results obtained can be summarized as follows : 1.Development of Softwares for Calculating 3-D Magnetic Field (1)The finite element formulations of various methods(A-phi, T-OMEGA) are investigated. (2)The CPU time for edge element is shorter than that for nodal element. (3)The convergence of nonlinear iteration of Newton-Raphson method is improved by introducing the nonlinear programming technique. (4)Method for analyzing eddy current in moving conductor is investigated. (5)3-D time-periodic finite element method is developed. 2.Verification of Calculation Methods of Force and Torque The force and torque of verification models are analyzed, and the accuracies of calculation methods of force and torque are compared each other. 3.Development of Optimal Design Method Optimal design method which determines the size and shape of electrical machinery is developed by combining the finite element method and the nonlinear programming method. 4.Development of 3-D Pre-and Post-Processors The user friendly 3-D mesh generator and post-processor for finite element analysis are developed., Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, 1992 -1993, Grant-in-Aid for international Scientific Research, Okayama University - Verification of Softwares for 3-D Eddy Current Analysis
NAKATA Takayoshi; FUJIWARA Koji; TAKAHASHI Norio; MORISUE Toshiya; NAKAMAE Eihachiro; ONUKI Takashi
Softwares of various methods for 3-D eddy current analysis are developed, and problems of various methods are investigated. The flux and eddy current distributions of standard models for the verification of softwares are analyzed, and they are compared with measured values. The results obtained can be summarized as follows : 1. Investigation of Problems of Various Methods of Analysis and Development of Softwares (1) The finite element formulations of various methods (A-phi, A-phi-OMEGA, T-OMEGA) and problems in applying each method are investigated. (2) The CPU time for edge element is shorter than that for nodal element. (3) The gauge condition of the A-phi method and the grad phi are investigated. (4) The boundary element method using the scalar potential and the accuracy of the combination method of finite and boundary elements are investigated. The surface magnetic charge method is expanded to eddy current analysis. (5) The representation of magnetization curve of anisotropic material in an arbitrary direction is investigated. (6) 3-D transient analysis of coupled problem including moving bodies is investigated. 2. Analysis of Flux and Eddy Current Distributions of Verification Models and Comparison with Measured Values 3-D magnetic field and eddy current distributions of verification models are analyzed, and the CPU time and memory storage are compared each other. The user friendly 3-D pre- and post-processors for finite element analysis are developed. The accurate measuring system of flux and eddy current distributions utilizing newly developed prove method is established. The measured 3-D flux and eddy current distributions are compared with calculated values., Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, 1989 -1991, Grant-in-Aid for Co-operative Research (A), Okayama University - Design of Optimal Structure of AC Superconducting Wire Using 3-D Finite Element Method
TAKAHASHI Norio; FUJIWARA Koji
A new method for analyzing 3-D magnetic fields in ac superconducting wires has been developed. The verification of the method for calculating the coupling loss of ac superconducting wire is carried out by comparing the calculated values with measured ones. It is also shown that the opotimal structure of the superconducting wire can be investigated by using the newly developed numerical method. The results obtained can be summarized as follows : 1. Development for analyzing 3-D Magnetic Fields in AC Superconducting Wires A new method for analyzing 3-D coupling current in multifilamentary superconducting cable is developed taking efficiently into account the anisotropy of conductivity. 2. Pre- and Post-Processors for 3-D Analysis As the multifilamentary ac superconducting wire is twisted, ita 3-D mesh is complicated. Then, an efficient graphic system for producing 3-D meshes of ac superconducting wire is developed. 3. Measurement of AC Losses The ac superconducting magnet (60Hz) is produced, and the coupling loss is measured by using the pick-up coil method. It is verified that the ac losscan be divided into hysteresis loss and coupling loss using the two frequency method. The measured coupling loss is compared with the calculated value, and it is shown that the coupling loss is very much affected by the contact resistance between the strands. 4. Optimal Structure of AC Superconducting Wire The effects of thestructure of cable and the matrix (CuNi) on coupling losses are investigated. It is shown that the potimal design of ac superconducting wire is possible by using new method developed in this research., Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, 1989 -1990, Grant-in-Aid for General Scientific Research (C), Okayama Univeristy - アモルファス金属の磁気特性測定洋標準試験器の試作
中田 高義; 藤原 耕二; 高橋 則雄
磁性材料の磁気特性測定用単板磁気試験器を解析するための新しい三次元数値解析法を開発し、それを用いて、試験器の最適構造及び寸法を検討するとともに、実験的検討も行い、数値解析法等の妥当性を明らかにした。本研究の成果を要約すれば、以下のようになる。 1.磁束が与えられた三次元有限要素法の開発 励磁巻線中の電流しか与えることのできなかった通常の有限要素法を改良し、Bコイルに鎖交する磁束の時間的変化を境界条件として与えて。単板磁気試験器内の三次元磁界の分布を求める手法を開発した。本手法の開発により、実際の励磁条件を考慮した解析が可能になった。 2.数値シミュレ-ションによる最適構造の決定 磁界の強さや鉄損等を測定する場合の誤差要因である試料中のうず電流分布を、数値シミュレ-ションによって解析することにより、ダブルヨ-ク型試験器が、試料のオ-バ-ハングの影響をほとんど受けないことを明らかにした。また、シングルヨ-ク型試験器を用いた場合の誤差とオ-バ-ハングの長さ及びヨ-ク間の距離の関係を定量的に検討した結果、シングルヨ-ク型の場合でも、Bコイル及びHコイルの長さを調節すれば、ダブルヨ-ク型と同様に精度良い測定が可能であることを示した。さらに、巻線の寸法及び素線径と励磁電圧波形のひずみ率の関係を検討し、波形ひずみが最も少ない。最適な巻線の寸法及び素線径が存在することを明らかにした。 3.実験的検討 数値シミュレ-ションによって得られた最適構造及び寸法の、アモルファス金属用単板磁気試験器を制作して、磁束分布及びうず電流分布を測定し、解析結果と比較した。その結果、今回開発した数値解析法及びそれを用いた最適構造及び寸法の検討が妥当であることが確認できた。, 日本学術振興会, 科学研究費助成事業, 1989 -1989, 試験研究, 岡山大学 - Development of Program of 3-D Finite Element Method for Analyzing Magnetic Fields in Electrical Machines Excited from Voltage Sources
NAKATA Takayoshi; FUJIWARA Koji; TAKAHASHI Norio
A new method for analyzing 3-D magnetic fields in electrical machines excited from voltage sources has been developed. the program for the method is developed, and the method is expanded to the analysis of time-periodic phenomena and the analysis of circulating currents in multi-conductors connected in parallel to voltage sources. The results obtained can be summarized as follows: 1. Finite Element Formulation for 3-D Nonlinear Analysis and Investigation of Boundary Conditions The finite element formulation is shown taking into account the anisotropy of magnetic materials. Boundary conditions in 3-D analysis is investigated, and the computer storage and the CPU time can be reduced. 2. Development of 3-D Finite Element Method for Analyzing Magnetic Fields in Electrical Machines Excited from Voltage Sources A new method is developed by treating magntizing currents as unknown variables. It became possible to analyze magnetic fields in electrical machines under actual operating conditions. 3.Development of Programs Efficient programs for analyzing 3-D magnetic fields are developed by utilizing many kinds of subroutines. 4. Investigtion of Problems of Applying the Method to Electrical Machines The method is expanded for the analysis of time-periodic nonlinear magnetic fields with eddy currents. Moreover, it became possible to analyze circulating currents in multiconductors connected in parallel to voltage sources. 5. Expansion to the Analysis on Micro-Computers In order to reduce the computer storage, the ICCG method is introduced so that the program can run on micro-computers., Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, 1987 -1988, Grant-in-Aid for Developmental Scientific Research, Okayama University - Development of Nd-Fe-B Magnet Generator for Small Hydraulic Power Station
NAKATA Takayoshi; FUJIWARA Koji; TAKAHASHI Norio
A method for analyzing magnetic characteristics of permanent magnet generator is established. The optimal configuration of magnets, magnetization methods Nd-Fe-B permanent magnets are investigated. The verification of numerical analysis is also carried out by experiments. The results obtained can be summarized as follows: 1. Development of Simulation Method The finite element method is improved so that the performance characteristics of permanent magnet generator can be analyzed. Moreover, a new method for analyzing the magnetic field in a capacitor-discharge impulse magnetizer is established. 2. Optimal Configurations of Magnets It is shown that the permanent magnet should be set in the radial or inclined direction in order to increase the flux density. The magnetization of permanent magnet after assembling. and one-pole magnetization are preferable. 3. Demagnetization of Magnet The optimal configuration of magnet to prevent the demagnetization due to the armature reaction under short-circuit is shown. 4. Experiments A model generator is manufactured, and the measured flux densities are compared with calculated results., Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, 1987 -1988, Grant-in-Aid for General Scientific Research (C), Okayama University
Research Seeds
- Measurement of magnetic properties of magnetic materialResearch Fields: Electric and ElectronicsAffiliation/Name: Koji Fujiwara:Yasuhito Takahashi
- Magnetic field analysis of electiric devicesResearch Fields: Electric and ElectronicsAffiliation/Name: Koji Fujiwara:Yasuhito Takahashi
- Solar photovoltaics systemResearch Fields: Electric and Electronics, Environment and EnergyAffiliation/Name: Koji Fujiwara:Yasuhito Takahashi
- Development of power supplyResearch Fields: Electric and Electronics, Environment and EnergyAffiliation/Name: Koji Fujiwara:Yasuhito Takahashi
