Comparative Study of Enhancing Torque Performance Design Methods Based on Spoke-Type PMSMs

This article investigates three different rotor topologies of permanent magnet synchronous motors (PMSMs), namely the basic spoke-type permanent magnet rotor (BSPM), surface spoke-type permanent magnet rotor (SSPM), and interior spoke-type permanent magnet rotor (ISPM). A systematic comparison and analysis of their electromagnetic performance are conducted under no-load, rated-load, and overload conditions, with emphasis on key characteristics such as the flux density distribution, no-load back electromotive force (EMF), cogging torque, rated output torque, and overload potential. Furthermore, critical design indicators including torque density, required permanent magnet (PM) volume, and PM material utilization are thoroughly evaluated. The findings indicate that the SSPM exhibits a higher overload potential and reduced torque ripple. An evolutionary algorithm (EA) is adopted to improve the SSPM and optimize its torque performance, significantly reducing torque ripple without sacrificing average torque. The comprehensive assessment provides valuable insights into the relative strengths and limitations of each rotor topology for various application scenarios.