A V-Shaped PM Vernier Motor With Enhanced Flux-Modulated Effect and Low Torque Ripple

This paper proposes a new V-shaped permanent magnet vernier (V-PMV) motor for potential applications in direct-drive system. By utilizing the V-shaped PM topology and suitable pole-slot ratio, not only the flux leakage can be reduced effectively which is inevitable in traditional surface-mounted and spoke-type vernier permanent magnet (VPM) motor, but also the utilization of air-gap magnetic field harmonics can be improved. Moreover, dummy slots are employed on the inner edge of rotor, so that the torque ripple can be reduced. To fairly estimate electromagnetic performances of the proposed V-PMV motor, an existing flux-concentrating VPM motor is selected purposely and designed with the same size for comparative analysis by using the finite-element method. The simulation results indicate that the V-PMV motor can offer the advantages of high PM utilization, and low cogging torque and torque ripple.

I. Introduction

Vernier permanent magnet (VPM) motors have attracted more and more interest and attention, which have been considered as one of the promising candidates for direct-drive applications, such as electric vehicles and wind power generation [1], [2]. As one of the new type of flux-modulated motors, VPM motors have abundant harmonic components in air-gap magnetic field, thus possessing the advantage of high torque density.