Analysis on cogging torque of driving in-wheel motor for electric vehicle

Abstract

In order to reduce the torque fluctuation, vibration and acoustic noise of driving in–wheel motor for electric vehicle, this paper researches the generation mechanism and influence factors of cogging torque. Based on energy method and Fourier expansion, an analytical method is proposed to establish the expression of cogging torque, which can express its relation with design parameters. Based on the expression, the match of pole and slot, pole arc coefficient and permanent magnet eccentric distance are analysed and studied. Ansoft software is used to establish a time–varying movement electromagnetic field finite element model, which can compute the cogging torque about the different match of the pole and slot, different pole arc coefficient and different permanent magnet eccentric distance, in order to obtain the change regularity of the corresponding cogging torque. The conformity of the final simulation computation results with the theoretical analysis indicates this method can be used to provide a theoretical basis to make further optimal design of the new driving in–wheel motor and its control system, so as to reduce torque ripple of in–wheel motor.