Multi-Objective Optimization of an Outer-Rotor V-Shaped Permanent Magnet Flux Switching Motor Based on Multi-Level Design Method

Abstract

This paper proposes an outer-rotor V-shaped permanent magnet flux switching (V-PMFS) motor for potential applications in in-wheel direct drive system. However, the cogging torque and torque ripple of the outer-rotor V-PMFS motor are relatively high, which may lead to mechanical vibration and acoustic noise, especially in low speed operation. To improve the overall performances of the outer-rotor V-PMFS motor, a multi-objective optimization method based on multi-level design method is proposed. According to the effect of the design variables on the optimization objectives, sensitivity analysis method is used to divide the design variables into two levels. Then, the two levels of design variables are optimized with two different optimization methods. After optimization, electromagnetic performances between initial and optimal motors are compared. Finally, a prototype motor is manufactured and tested. Both electromagnetic performance analyses and experimental results verify the validity of the proposed optimization method.