Hybrid Stator Design of Fault-Tolerant Permanent-Magnet Vernier Machines for Direct-Drive Applications

In this paper, a new hybrid stator developed from conventional open-slot and split-tooth stators is proposed for a fault-tolerant permanent-magnet (PM) vernier (FTPMV) machine to improve its performance. The design considerations of the new hybrid stator for FTPMV machines are presented. Afterward, on the basis of the designed hybrid stator, new FTPMV machines with surface-mounted and spoke-array PMs are proposed and analyzed, respectively. Comparative evaluation of the proposed FTPMV, conventional FTPMV, and the conventional PM machines are performed by using finite-element (FE) analysis. It is found that the proposed FTPMV machines with the new hybrid stator definitely offer the improved performances such as higher torque density, higher power factor, and lower iron core loss as compared to that of the conventional FTPMV machines. Finally, the experiments on the prototype machines are conducted, verifying the FE analysis results and effectiveness of the proposed hybrid stator design for FTPMV machines.