Reducing Acoustic Noise of Axial-Gap SRMs by Decreasing Axial Electromagnetic Force Ripple

Takahiro Tokita, Hiroki Goto, Osamu Ichinokura

Research output: Contribution to journalArticlepeer-review


Switched reluctance (SR) motors are motors that utilize the reluctance torque originating in the magnetic saliency between the stator and the rotor, which are made up of an electromagnetic steel sheet and windings without a permanent magnet. Because of their robustness and simple structure, SR motors are suited for use as the in-wheel motor for traction motors of vehicles. In a flat space such as is present in in-wheel motors, the axial-gap structure has an advantage compared with the conventional radial-gap structure for the space factor of a motor. An axial-gap in-wheel SR motor was tested in a microbus, and the bus could be successfully driven. The test results regarding the motor performance were satisfactory. However, the motor emits a loud sound. The acoustic noise of the axial-gap SR motor is mainly caused by the axial electromagnetic force. This paper presents a method of reducing acoustic noise that is based on a model of the electromagnetic force on the axial-gap SR motor.

Original languageEnglish
Pages (from-to)40-47
Number of pages8
JournalElectrical Engineering in Japan (English translation of Denki Gakkai Ronbunshi)
Issue number1
Publication statusPublished - 2017 Apr 1


  • acoustic noise
  • axial-gap type
  • electromagnetic force
  • in-wheel motor
  • switched reluctance motor
  • vibration

ASJC Scopus subject areas

  • Energy Engineering and Power Technology
  • Electrical and Electronic Engineering


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