Torque Ripple Analysis and Model of Symmetrical Six-Phase Fault-Tolerant PMSM

This paper focuses on the torque ripple analysis of interior permanent magnet synchronous motor equipped with fractional slot concentrated winding under fault conditions. When the motor suffers from faults, torque ripples will appear. In order to get better performance under fault conditions, it is necessary to make clear the source of torque ripples. In general, the torque ripples are composed of three portions. The first is due to the negative sequence current. The second is the interaction between the field generated by the third harmonic component of PM flux and the field generated by the third harmonic space current. The last is the interaction between the fields generated by currents of different spaces. Especially, the last portion is revealed in this paper for the first time. Besides, the motor model of this kind established yet has not revealed the last portion of torque. According to the inductance matrix of phase winding, the motor model of this kind is established, which can fully reveal the motor torque. Moreover, the finite element analysis is conducted to verify the effectiveness of the motor model.