A new torque ripple test method based on PMSM torque ripple analysis for electric vehicles

This paper analyzes the reason of Low-speed vibration in an electric vehicle, builds the mathematical equation of powertrain torsional vibration. Then, the model of torque ripple considering non-sinusoidal magnetic field distribution is built, orders and frequencies of torque ripple in PMSM is predicted. According to the relationship between the torsional vibration in low-speed of the electric vehicle and the frequency of motor torque ripple, for the situation that there are few literatures on the torque ripple analyze and test method of PMSM in electric vehicles, a dynamic torque ripple test bench is presented. The torque ripple frequency analysis is verified by testing. Because there are amplitude and phase distortion caused by the dynamic test, we presented a new locked-rotor static method.instead of the dynamic test. It provides an accurate means of testing and evaluation for the torque ripple of PMSM in electric vehicles preliminarily.