Torque ripple minimization for PMSM considering harmonic magnet flux phase

Abstract

Due to the existence of cogging torque, magnet flux harmonics and inverter dead time, permanent magnet synchronous motor (PMSM) has torque ripple during operation, which limits its application in high-precision situations. Stator current optimization is an easy-to-apply and accurate torque ripple suppression approach. However, existing methods fail to consider the effect of magenet flux phase angle on optimal current calculation. In this paper, a torque ripple minimization method considering harmonic magnet flux phase is presented, which uses torque waveform of an electric angular period as the optimization object. By deducing the electromagnetic torque model considering harmonic magnet flux, the torque is expressed as a dense sequence. Based on this, the objective function including torque ripple and losses minimization is constructed and optimized by genetic algorithm (GA) to obtain the optimal harmonic current. Experiment results show that the proposed approach can calculate the optimal harmonic current accurately and suppress the torque ripple effectively.