Optimization and Analysis of a Reverse-Salient Hybrid Permanent Magnet Motor Used for Electric Vehicles

The reverse-salient permanent magnet motors (RSPMMs) have attracted widespread attention in the field of electric vehicles due to its wide constant power speed range and strong overload capacity. However, there are few researches on the design and optimization of RSPMMs used for electric vehicles (EVs). In this paper, a reverse-salient hybrid permanent magnet motor (RSHPMM) is proposed. By analyzing the motor parameters that affect the distribution of the operating interval, the optimization objectives are reasonably selected. To reduce the difficulty of optimization, Sobol global sensitivity analysis is introduced for parameter analysis. This approach fully considers the interactions between two parameters. After eliminating non-critical parameters, a genetic algorithm is employed for multi-objective optimization. The electromagnetic performance of the RSHPMM is investigated by finite element method and is compared with a conventional interior permanent magnet motor (CIPMM). Finally, a prototype is manufactured and tested. The results show that the RSHPMM has lower ripple torque, stronger flux-weakening ability, wider constant-power speed range, and higher efficiency at a high speed than the CIPMM. The amount of rare-earth permanent magnets is only 44% of that of CIPMM. The validity of the design and optimization approaches of the RSHPMM used for EVs is verified.