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77 results on '"Toba, Akio"'

19. Sensorless torque control of salient-pole synchronous motor at zero-speed operation

Author

Aihara, Takashi, Toba, Akio, Yanase, Takao, Mashimo, Akihide, and Endo, Kenji

Subjects
Synchronous electric motors -- Research, Torque -- Research, Control systems -- Research, Business, Electronics, Electronics and electrical industries
Abstract

A position and speed sensorless control using the counter electromotive force of permanent-magnet motor (PM) debases the control performance at a low speed. We will propose a controllable system at full speed, including a zero speed using saliency. At low speed, the sensorless control is made by observing a current ripple at a time when alternating voltage has been applied to a salient-pole motor. Also, for discriminating the S and N poles of the magnet, magnetic saturation is used. A device has been applied to the motor rotor to allow the magnetic saturation to come about easily. Furthermore, at a time of high speed, drive at a full-speed range has been accomplished by switching smoothly over to a sensorless driving system making use of counter electromotive force. All algorithms are implemented by software, and this system can operate successively from starting to high-speed operation. Shown herein are the operational principles at a low speed, analysis and experimental results, the control scheme, how to changeover the control mode at a high speed, and the experimental results. Index Terms - Permanent-magnet motor, salient pole, sensorless drive.

Published
1999

20. Auxiliary resonant commutated pole inverter using two internal voltage-points of DC source

Author

Toba, Akio, Shimizu, Toshihisa, Kimura, Gunji, Shioya, Mitsuo, and Sano, Shigeru

Subjects
Electric inverters -- Innovations, Pulse-duration modulation -- Usage, Business, Computers, Electronics, Electronics and electrical industries
Abstract

This paper presents a new auxiliary resonant commutated pole inverter that has series-connected batteries as the dc source. This inverter has two main switches and two auxiliary switches, and of all these devices achieve soft switching. The resonant operations are employed only during the commutating intervals; therefore, pulsewidth modulation (PWM) can be applied to the circuit. This circuit has the feature of using two internal voltage points of the dc source. Consequently, the circuit has the advantages of stability, simplicity in control, and high efficiency. The principle of the circuit operation and the experimental results are described in this paper. Index Terms - Auxiliary resonant commutated pole, batteries, pulsewidth modulation, soft switching.

Published
1998

23. Japan - IAEA Joint Nuclear Energy Management School 2016

Author

Yamaguchi, Mika, Hidaka, Akihide, Ikuta, Yuko, Murakami, Kenta, Tomita, Akira, Hirose, Hiroya, Watanebe, Masanori, Ueda, Kinichi, Namaizawa, Ken, Onose, Takatoshi, Yamashita, Kiyonobu, Uesaka, Mitsuru, Kita, Tomohiko, Toba, Akio, Kitabata, Takuya, and Sawai, Tomotsugu

Abstract

IAEAは、将来原子力エネルギー計画を運営管理するリーダーとなる人材の育成を目的とした原子力エネルギーマネジメントスクールを2010年より世界各国で開催している。原子力機構は、日本原子力人材育成ネットワークの事務局として、同ネットワークに参加している東京大学、日本原子力産業協会及び原子力国際協力センターとともに、2012年よりIAEAと共催という運営形態で上記スクールを日本で継続的に開催している。2016年は、IAEAの専門家を講師とした講義とともに、日本開催の特徴を生かしつつ、日本人専門家の協力を得て、福島第一原子力発電所事故の教訓、日本の原子力分野における経験・技術の紹介などを含む独自性のある講義を提供した。施設見学では、多様な原子力関連施設の見学を福井県及び神戸市で実施した。本スクールの開催を通して、我が国の若手人材の国際化および新規原子力導入国等の人材育成へ貢献することができ、また、我が国とIAEAとの協力関係の促進に資することができた。加えて、関係機関が一体となって協力し合い開催することにより、国内の原子力人材育成ネットワークの協力関係を強化することができた。, Since 2010, IAEA has held the NEM School to develop future leaders who plan and manage nuclear energy utilization in their county. Since 2012, JAEA together with Japan Nuclear HRD Network, University of Tokyo, Japan Atomic Industrial Forum and JAIF International Cooperation Center have cohosted the school in Japan in cooperation with IAEA. Since then, the school has been held in Japan every year. In 2006, Japanese nuclear technology and experience, such as lessons learned from the Fukushima Daiichi Nuclear Power Plant accident, were provided to offer a unique opportunity for the participants to learn about particular cases in Japan. Through the school, we contributed to the internationalization of Japanese young nuclear professionals, development of nuclear human resource of other countries including nuclear newcomers, and enhanced cooperative relationship with IAEA. Additionally, collaborative relationship within the network was strengthened by organizing the school in Japan.

Published
2017

24. Suppression of short-circuit current in halt sequence to stop two-level inverter connected to PMSM during regeneration mode

Author

Toba Akio, Tsuyoshi Nagano, and Jun-ichi Itoh

Subjects
Physics, business.industry, 020208 electrical & electronic engineering, Mode (statistics), Electrical engineering, 020302 automobile design & engineering, 02 engineering and technology, law.invention, Inductance, Capacitor, 0203 mechanical engineering, Control theory, law, 0202 electrical engineering, electronic engineering, information engineering, Inverter, Current (fluid), business, Short circuit, Voltage, Sequence (medicine)
Abstract

This paper discusses an approach to suppress the rise of the short-circuit current in a halt sequence which is named “Flux-weakening Short-circuit halt sequence (FSHS)”. When grid faults stop a back-to-back system which has a DC-link capacitor with a small capacitor while in regeneration, the DC-link voltage increases rapidly due to regeneration current. FSHS interrupts the regeneration current to stop the two-level inverter and suppresses the rise of the DC-link capacitor voltage without a dynamic brake circuit. However, FSHS cannot suppress the rise of short-circuit current caused by the q-axis current which rises during the short-circuit mode when the regeneration current is low or PMSM with small synchronous inductance is driven. The improved FSHS suppresses the rise of the short-circuit current in low-load region by maintaining the q-axis current around zero until before the mode is changed to Sequence II at zero-crossing point of the current. In the experiment, it is confirmed that the improved FSHS suppresses to 85% of the short-circuit current when the regeneration current is low.

Published
2016

29. Generic Torque-Maximizing Design Methodology of Surface Permanent-Magnet Vernier Machine

Author

Toba, Akio and Lipo, Thomas A.

Subjects
Magnets, Permanent -- Design and construction, Magnetic fields -- Measurement, Torque -- Analysis, Business, Computers, Electronics, Electronics and electrical industries
Abstract

A surface permanent-magnet vernier machine (SPMVM) has a toothed-pole structure, and its highly nonlinear relationship between its dimensions and magnetic field makes its design cumbersome. This paper presents a generic design methodology for the machine which brings out its torque-maximizing structure in a convenient manner. Various suggestions concerning the design of the SPMVM are also set forth. Index Terms--Case study, design, experiment, permanent magnet, theoretical analysis, torque, vernier machine.

Published
2000

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