Analysis and Optimization of Asymmetric Hybrid Permanent Magnet Motor for Electric Vehicle

An asymmetric hybrid permanent magnet motor (AHPMM) is proposed for the traditional permanent magnet motor (TPMM) with a large amount of rare earth materials and high cogging torque. The equivalent magnetic circuit model of the motor is established and the factors affecting the fluctuation of cogging torque are analyzed. With the objective of reducing the torque ripple and cogging torque of the AHPMM, the motor is parametrically modeled and analyzed, and multi-objective hierarchical optimization of the motor parameters is carried out using a hybrid algorithm combining the response surface algorithm and the single scan method, which ultimately determines the optimal combination of motor dimensional parameters. The electromagnetic performance of the AHPMM compared to the TPMM is analyzed using the finite element method. The results show that, without any decrease in output torque, the use of rare-earth materials is reduced by 18.5%, the cogging torque and the total harmonic distortion of the No-load back EMF waveform are reduced by 0.78 Nm and 4.7% respectively compared to the TPMM. Finally, a prototype motor is manufactured and the validity of the theoretical analysis and design of the AHPMM is verified through experiments.