Analysis of a Nine-Phase Tangential-Flux PM Synchronous Motor with Skewed Stator and Dual Rotor Hubs for Electric Vehicles

This paper reports on the analysis of a nine-phase phase tangential-flux PM (TFPM) motor with skewed stator and dual rotor hubs suitable for electric vehicles. First, the initial motor is designed with a single rotor magnetic hub of a mild steel material M800-50A type and a non-skewed stator. Secondly, the stator of initial motor is skewed as a function of stator slot pitch angle, and then as function of rotor magnet pole pitch angle to study the effect on performance parameters of interests. At last, the best skewed angle is selected for the proposed design, which comprises of dual rotor hubs with different magnetic materials. The proposed motor is designed and modelled using Finite Element Method (FEM). The FEM results evidenced that the proposed nine-phase TFPM motor realized a considerable torque per rotor volume, significant average torque, reduced torque ripple and cogging torque, while having a high peak torque and extended speed range proficiency.