Design Optimization of Nine-phase Induction Motor for EV Traction Applications

The transition to electric vehicles (EVs) needs advanced motor and drive technologies optimized for desired traction performance. When designing an electric motors for EV applications, numerous factors need to be considered, including high reliability, high power density, low cost, high torque density, high efficiency over wide operation regions, and low torque ripple. As traditional three-phase motor designs face increasing challenges in meeting these performance goals, multiphase motor designs are becoming increasingly attractive, but the related design optimization has not been thoroughly investigated. Multiphase induction motors (IMs) are among the best rare-earth free traction motors for EV applications. In this paper, the design and multi-objective optimization of a nine-phase IM is presented, shedding light on the motor performance during rated and peak loading conditions. Moreover, the motor performance at the maximum speed is considered to ensure that practical EV constraints are met. The design optimization process is developed using Ansys Electronics Desktop and Ansys optiSLang. Finally, intensive finite element simulations are carried out to validate the superiority of the optimal design.