Analytical approach for cogging torque reduction in flux-switching permanent magnet machines based on magnetomotive force-permeance model

Xiaofeng Zhu, Wei Hua, Zhongze Wu, Wentao Huang, Hengliang Zhang, Ming Cheng

Research output: Contribution to journalArticle

19 Citations (Scopus)


Flux-switching permanent magnet machine typically suffers from relatively high cogging torque due to its special doubly salient structure and high air-gap flux density, causing undesired torque ripples, as well as acoustic noise and vibration, especially at low speeds. In this paper, an analytical expression of cogging torque is derived based on a magnetomotive force-permeance model, through which the optimal design parameters and dimensions, such as combinations of stator slots and rotor poles, skewing angle, stator tooth width, rotor tooth width, and magnet thickness, can be determined. Based on the derived analytical model, two novel approaches for cogging torque reduction are proposed, i.e., asymmetric magnetomotive force and asymmetric permeance, respectively, and consequently, the optimal designs are also acquired analytically. However, it is also found that the optimal choice of the proposed techniques depends on the combinations of stator slots and rotor poles of the machines. Finally, the effectiveness of the proposed approaches is verified by both finite element analytical predictions and experimental results.

Original languageEnglish
Article number8010298
Pages (from-to)1965-1979
Number of pages15
JournalIEEE Transactions on Industrial Electronics
Issue number3
Publication statusPublished - 1 Mar 2018


  • Analytical models
  • cogging torque reduction
  • finite element analysis
  • flux switching
  • optimization
  • permanent magnet (PM) machines
  • torque

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Electrical and Electronic Engineering

Cite this