Torsional Vibration Analysis and Suppression of Interior Permanent Magnet Synchronous Motor With Staggered Segmented Rotor for Electric Vehicles

Permanent magnet (PM) synchronous motor (PMSM) has been widely applied in electric vehicles (EVs) due to its advantages of high efficiency and high power density. However, the torsional vibration generated by different torsional forces between the rotor and the load or between different rotor segments in the axial direction can significantly reduce the reliability and service life of the motor system. In this article, a new rotor segmented motor is proposed for EVs to eliminate the torsional vibration while ensuring the torque quality. The principle of torsional vibration generation in conventional rotor step-skewing motors is presented, and the technology for reducing torsional vibration in the proposed rotor segmented motor is illustrated. Afterward, the structures of the rotor step-skewing motor and the proposed motor are exhibited and illustrated. The finite element analysis (FEA) models of two motors are established, and the torsional vibration characteristics, including torsional force, torsional mode, and shaft system deformation, are simulated and compared. Finally, the two motors are prototyped and tested, and the results show that the torsional vibration excited by the difference in the axial structure of the motor can be significantly attenuated by the proposed motor.