Cost-effective vernier permanent-magnet machine with high torque performance

Abstract

As a promising candidate applied in direct-drive applications due to high torque characteristics at low speed, vernier permanent-magnet (VPM) machines have been paid increasingly attention in many direct-drive fields, such as electric vehicle propulsion and wind power generation. In order to reduce the flux leakage and improve PM utilization rate on the premise of not decreasing the output torque, a five-phase fault-tolerant VPM machine is proposed with unipolar ferrite material between FMPs and surface mounted unipolar NdFeB in rotor, which not only remains the advantage of fault tolerance, but also significantly improves the torque density and reduce torque ripple simultaneously with considerable less consumption of rare-earth PM material.