Professor Yoshifumi Okamoto at Electromagnetics Laboratory, Department of Electrical and Electronic EngineeringFaculty of Science and Engineering has been selected for the Power Academy Research Grant for Specially Promoted Research

Professor Yoshifumi Okamoto of Electromagnetic Engineering Laboratory, Department of Electrical and Electronic Engineering Electrical and Department of Electrical and Electronic Engineering Engineering, Faculty of Science and Engineering Hosei University has been selected for the Power Academy Research Grant "Specially Promoted Research", and the acceptance ceremony for the 2022 Power Academy Research Grant "Specially Promoted Research" was held on January 24, 2023 at Hosei University Koganei Campus.

◆Name of Awarded Paper
Development of Nondestructive Magnetization Estimation System for Rare-Earth Magnets Using Leakage Flux of Permanent Magnet Synchronous Motors

Principal Investigator
OKAMOTO Yoshifumi (Professor, Department of Electrical and Electronic Engineering Hosei University)

Co-researchers
Shinji WAKAO (Professor, Department of Electrical and Computer Engineering, School of Advanced Faculty of Science and Engineering Science and Engineering, Waseda University)

Research collaborators
Seito Nakamura (Doctoral Student 1st, Major in Electrical and Electronic EngineeringGraduate School of Science and Engineering Science and Graduate School of Science and Engineering Hosei University)
Masahide Shioyama (1st year of Master course, Major in Electrical and Electronic EngineeringGraduate School of Science and Engineering Science and Graduate School of Science and Engineering, Hosei University)

Date of Award
January 23, 2023 (Monday)

◆Summary of Research
　Permanent magnet synchronous motors (PMSMs) are the driving source of xEVs. Therefore, it is important to verify the performance of permanent magnets loaded in PMSMs in order to maintain high quality design and performance of PMSMs. In this study, a technique (MELF: Magnetization Estimation using Leakage Flux) is developed to nondestructively estimate the performance of permanent magnets by using the leakage flux of PMSMs while they are loaded in PMSMs.
The process of evaluating the performance of permanent magnets by PMSM leakage flux is similar to our "blood test" process, in which the PMSM flux is compared to "human blood".

◆Expected research results
With the practical application of MELF, the following two applications are expected.
(1) In the design process of permanent magnet synchronous motors (PMSMs), magnetization is often performed after loading permanent magnets in an unmagnetized state into the rotor and stator iron cores. The MELF uses the leakage flux of the magnetic circuit to estimate the magnetization distribution inside the permanent magnet in all areas, and thus can detect imperfectly magnetized areas inside the magnet.
In the future, the electrification of not only automobiles but also various types of transportation machinery will be promoted in order to achieve carbon neutrality. Therefore, it is inevitable that PMSMs, which are the driving source of these machines, will become smaller and more powerful, resulting in higher rotation speeds of PMSMs. The non-destructive evaluation of permanent magnet performance from the leakage flux of PMSMs can be applied to the maintenance of PMSM performance and the effective use of rare earth magnets.

◆Attendees at the adoption ceremony (titles omitted)
Professor, Department of Electrical and Electronic EngineeringMajor in Electrical and Electronic Engineering Department of Electrical and Electronic Engineering Faculty of Science and Engineering Hosei University
　　 OKAMOTO Yoshifumi
Professor, Department of Electrical and Computer Engineering, Faculty of Science and Engineering, Waseda University ( Trustee: Research Promotion)
　　Shinji WAKAO
Professor, Department of Applied Informatics Faculty of Science and Engineering Hosei University ( Vice President Executive Trustee )
　　 KANAI Atsushi
Professor, Department of Clinical Plant Science Faculty of Bioscience and Applied Chemistry Hosei University (Dean, Graduate School of Science and Engineering )
　　 HAMAMOTO Hiroshi
Professor, Department of Electrical and Electronic EngineeringFaculty of Science and Engineering Faculty of Science and EngineeringFaculty of Science and Engineering Faculty of Science and Engineering Hosei University (Dean, Faculty of Science and Engineering )
　　 ITO Kazuyuki
Professor, Department of Electrical and Electronic EngineeringDepartment of Electrical and Electronic Engineering Department of Electrical and Electronic Engineering, Faculty of Science and Engineering, Hosei University (Head of Department of Electrical and Electronic Engineering )
　　 NAKAMURA Toshihiro
Director, Research and Development Center, Hosei University
　　Yoshiyuki Hino
Director, Koganei Office, Hosei University
　　Kosaku Kouno
Hosei University Graduate School Graduate School of Science and EngineeringMajor in Electrical and Electronic Engineering Doctoral Course, 1st Year Student
　　Seito Nakamura
Master's Student, Major in Electrical and Electronic Engineering Graduate School of Graduate School of Science and Engineering, Hosei University
　　Masahide Shioyama

The Tokyo Electric Power Company, Incorporated
Manager, Planning and Strategy Group, Research Management Office, Management Technology Strategy Research Institute, Tokyo Electric Power Company Holdings, Inc.
Technology Strategy Unit, Technology Management Office, Technology Strategy Unit, The Tokyo Electric Power Company, Incorporated
　　Takumi Yamamoto

Editorial Department, Newspaper Division, Japan Electric Association
　　Yoshihito Hama

Executive Director, Power Academy Secretariat
　　Osamu Okamura
Deputy General Manager
　　Susumu Minamijima
Deputy Director
　　Hiroyoshi Yamada
Affiliation, position, grade, etc. are as of the time of the award.

◆Reference
Report on the Results of the FY2022 Power Academy Research Grant "Specially Promoted Research" and "Budding Researchers" Adoption
https://www.power-academy.jp/info/2022/003385.html
https://www.power-academy.jp/info/2023/003407.html