Torque density improvement of permanent-magnet vernier machines for hybrid electric vehicle

In this paper, a novel method is presented to improve the torque density of pole-splitting permanent-magnet vernier machines (PSPMV), which has been proposed to meet the demands of hybrid electric vehicle (HEV) drive system. The interspace between the flux-modulation poles (FMP) deserves to be exploited for producing extra torque by embedding additional windings. Non-overlapping windings are adopted to achieve such objective. Two types of arrangement are employed in this article, and then their operating principles and efficacy are compared. By using the time-stepping finite element method (TS-FEM), the performance of this improvement is verified quantitatively.