Design and Optimization of a Five-Phase Reverse-Salient Fault-Tolerant Permanent Magnet Motor for Electric Vehicles

Owing to the merits of good fault-tolerant capacity, wide-speed range, and good sensorless operation capacity, a five-phase reverse-salient fault-tolerant permanent magnet (FPRSFT-PM) motor with the inductance characteristics of L_d > L_q is very suitable for the electric vehicle (EV) applications. However, due to the different effects of motor parameters caused by the realization of multiobjective performances such as good flux-weakening (FW) capacity and obvious reverse-salient characteristic, there are constraints in the process of realizing multiobjective performances, which cause serious interference to the design process of the FPRSFT-PM motor. Also, in the existing study, the design guidance for the FPRSFT-PM motor considering these different constraints is still absent. Hence, this article first develops the design criterion and optimization for the FPRSFT-PM motor considering multiobjective constraints. Furthermore, the FW ratio is innovatively introduced in the multiobjective optimization process to act as a new optimization objective and new objective functions are subtly changed, which can effectively balance the requirements of FW capacity and reverse-salient characteristic. Finally, the constraints between the FW capacity, reverse-salient characteristic, and the reluctance torque are greatly weakened, and all these performances of the FPRSFT-PM motor can meet the design requirements. Through simulation analysis and experimental tests, the rationality and validity of the proposed design criterion and optimization are verified.