Comparative study of dual PM vernier machines

Huan Qu, Zi Qiang Zhu, Toru Matsuura, Dusan Ivanovic, Takashi Kato, Kensuke Sasaki, Jim Greenough, Bob Bateman, David A. Stone, Martin P. Foster, Javier Riedemann

Research output: Contribution to journalArticlepeer-review


In this paper, two types of dual permanent magnet (PM) machines, i.e., stator slot dual-PM (SSDPM) machine and split-tooth dual-PM (STDPM) machine, are investigated and compared. Both machines have consequent pole structure with Halbach array PMs. Their difference lies in the position of stator PM. The SSDPM machine has Halbach array PMs in the stator slots, while the STDPM machine has PMs between the split teeth. Torque characteristics, i.e., average torques and torque ripples, of different slot/pole number combinations of the two machines are compared. The 24 stator slots/20 rotor slots/4 armature pole pair (24S20R4Pa) SSDPM machine with distributed windings and the 24 stator slots/10 rotor slots/4 armature pole pair (12S20R4Pa) STDPM machine with concentrated windings are compared under both open-circuit and on-load conditions. The results show that the SSDPM machine is more competitive by delivering higher torque density and higher power density.

Original languageEnglish
Article number12
Pages (from-to)1-16
Number of pages16
JournalWorld Electric Vehicle Journal
Issue number1
StatePublished - Mar 2021
Externally publishedYes


  • Dual permanent magnet (PM)
  • Electric vehicle (EV)
  • Flux modulation
  • Halbach PM array


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