Asymmetric and Symmetrical Rotor Core Shaping Techniques of IPMSMs for EVs

Three rotor core shaping methods, i.e. asymmetric notching, asymmetric partial and full rotor core shaping, are applied to the design optimization of interior permanent magnet synchronous machines for electric vehicles. The designs are also compared with their symmetrical counterparts. It is shown that without sacrificing average torque, all shaping techniques can reduce torque ripples, asymmetric rotor core shaping can further reduce the output torque ripple, and a partial rotor core shaping is as effective as fully shaped rotor core without having to increase the complexity of optimization.