Asymmetric Operation of Fifteen Phase Permanent Magnet Synchronous Motor and Torque Ripple Suppression of Stator Windings Switching

This paper is mainly concerned with the modeling of asymmetric operation of fifteen phase permanent magnet synchronous motor (PMSM) and the torque ripple suppression of the stator windings switching. The fifteen phase PMSM is connected by 3*5 phase star type and three neutral points are independent of each other. It aims to broaden the high efficiency area and extend the cruise mileage, three sets of windings units are designed at different base speeds, and the power of each winding is matched with the operating condition. In order to keep the motor system running high efficiency in whole condition, the control strategy for adding or removing high speed winding is utilized to make sure that the remaining windings work near the rated power. The torque ripple must be caused when the winding is switched, a control method of torque ripple suppression is proposed. Firstly, the inductance matrix of the 3*5 phase motor winding is analyzed when the parameters are symmetrical and asymmetrical, the vector control based on three d-q axes is built. Secondly, the asymmetric operation model of motor is built, and the corresponding control strategy of torque ripple suppression is proposed when the winding is added or removed. Finally, the simulation results of torque ripple are compared between direct switching and proposed control strategy.