Volume 67

Comparative Electromagnetic Performance of Axial Flux Permanent Magnet Motors with Three Different Rotor Topologies Xuyang Liu, Xue Yu, Junjie Jiang, Yu Wang

Abstract

Dual-stator axial flux permanent magnet motors (DSSR-AFPM) have been widely applied in electric vehicle drive systems due to their high torque density and compact structure. However, most existing DSSR-AFPM motors employ a surface-mounted permanent magnet (SPM) rotor topology, which suffers from the inability to utilize reluctance torque, high harmonic content in the air-gap flux density, and significant torque ripple. To overcome these drawbacks, this paper proposes a novel interior permanent magnet (NIPM) rotor with magnetic isolation slots. Under identical design constraints, the electromagnetic performances of three rotor topologies—SPM, surface-embedded permanent magnet (SEPM), and NIPM—are compared using three-dimensional finite element analysis. The results show that the NIPM rotor achieves a more sinusoidal air-gap flux distribution, reduced torque ripple, and enhanced flux-weakening capability, while maintaining high efficiency over a wide speed range.

Keywords Axial-flux permanent magnet machine, Dual-stator single rotor, Torque/power density, flux-weakening speed expansion