Coupling Harmonic Voltages Considered Harmonic Currents Injection Method for Torque Ripple Reduction

Torque ripple widely exists in vehicular permanent magnet synchronous motors, which degrades the quality of output torque and even causes undesirable vibration in the vehicular application. In this paper, we propose a torque ripple reduction method based on harmonic currents injection. Firstly, with considering a couple of positive and negative sequence harmonic current simultaneously, a harmonic voltages model of PMSM in multiple synchronous-frames is established. The model reveals that either positive or negative voltage alone can induce positive and negative currents in the meantime. Secondly, based on the coupling harmonic voltages model, a novel harmonic currents injection system is established by combining feedforward harmonic voltages and feedback harmonic currents control. Finally, simulations and experiments are conducted to validate our proposed control system. The results show that the feedforward harmonic voltages can remedy the limitation of feedback control on dynamic tracking performance of harmonic currents, and then improve the torque ripple reduction effect during the dynamic process.