Optimal Design of a Spoke-type Permanent Magnet Motor with Phase-group Concentrated-coil Windings to Minimize Torque Pulsations

This paper proposes a novel multistep design and optimization strategy to minimize torque pulsations in a spoke-type permanent magnet motor with phase-group concentrated-coil windings. Different from the conventional techniques that work on the motor itself, in the first step, an auxiliary inner stator is designed to suppress torque pulsations with the aid of a finite-element method (FEM). In the second step, the optimization by using the Kriging method and genetic algorithm, is then applied to the auxiliary inner stator to further reduce torque pulsations. In the third step, the harmonic injected current is utilized to suppress torque ripple by maintaining the required power, while the optimal input current waveform is optimized by the aforementioned algorithms based on the harmonic analysis of back electromotive force. Through the analysis results by the FEM, it shows that the cogging torque and torque ripple of the final model are significantly reduced by 95.7% and 70.0%, respectively, when compared with those of the initial model.