Variable Magnetization Machine in Electrified Vehicle Application

Takashi Fukushige, Takashi Kato, Kan Akatsu, Robert D. Lorenz

Research output: Contribution to journalArticlepeer-review


This paper describes variable magnetization machines, which are capable of varying the magnetization state (MS) of permanent magnets during operation. A pulse current on the stator windings creates a magnetic field on the rotor; this can be used to manipulate the MS of the rotor magnets. Regulating the MS according to the machine operating condition can reduce machine losses. A proof-of-principle machine was designed and fabricated. A series of experiments was conducted to evaluate the torque–speed envelope and efficiency contours of the fabricated machine. A full-scale machine was then designed with a modified magnetic circuit for application to an electric vehicle and evaluated using finite element analysis. A control strategy for the MS during machine operation is proposed, and the losses during a driving cycle with the strategy were evaluated.

Original languageEnglish
Pages (from-to)67-75
Number of pages9
JournalElectrical Engineering in Japan (English translation of Denki Gakkai Ronbunshi)
Issue number3
Publication statusPublished - 2016 Nov 1


  • efficiency
  • flux-intensifying machine
  • memory motor
  • permanent magnet synchronous machine
  • variable flux machine

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Energy Engineering and Power Technology


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