Design and Analysis of Five-Phase Fault-Tolerant Interior Permanent-Magnet Vernier Machine

A new five-phase fault-tolerant interior permanent-magnet (PM) vernier machine is proposed in this paper, which possesses both high reliability and high torque density at low speed. It adopts single-layer concentrated windings and fault-tolerant teeth to improve fault tolerance. Since the spoke-type PMs are designed, the air-gap flux density is greatly improved, even with less PM consumption, due to the flux focusing effect. In addition, some stator teeth parameters are optimized in the proposed machine, which in return further improves the torque density and decreases the torque ripple. The time-stepping finite-element method is used to investigate the performance of the proposed machine, as compared with an existing fault-tolerant surface PM vernier machine.