Analyze and Design of Six Phase Fault-Tolerant PMSM with Novel Slot Opening Distribution

Multi-phase permanent-magnet synchronous machines (PMSMs) have been widely used in safety critical applications due to its fault-tolerant ability. In this paper, the slot opening distribution for fraction slot winding and its influences on the winding factor and the coil pitch are analyzed, based on which several six phase fault-tolerant PMSMs with different slot opening distributions are proposed. The performance, including the magnetomotive force (MMF) harmonic spectrum, the eddy loss and the cogging torque, is evaluated in healthy condition. For the open-circuit and short-circuit condition, the performance before and after the fault-tolerant strategy adopted is compared and analyzed in terms of the MMF spectrum and the inductance feature. The tradeoff design of the slot opening distribution considering the fault-tolerant ability and the performance in healthy condition is concluded, which provides a generally guideline on the design of fault-tolerant PMSM.