A Method of Torque Ripple Reduction by Using Harmonic Current Injection in PMSM

Permanent Magnet Synchronous Machine (PMSM) is used for the traction motors in Electric Vehicle (EV) and Hybrid Electric Vehicle (HEV). However, PMSM makes vibration and acoustic noise in the connected load due to the torque ripple. Torque ripple reduction technique requires the modeling of accurate torque ripple and estimation of motor parameters considering magnetic saturation and magnet temperature variation. Existing approaches considering magnetic saturation and magnet temperature variation are complicated and difficult to realize. Therefore, this paper shows the torque ripple expression which is regarded as complex vector behavior. So far it can very easily decide the current reference to reduce torque ripple by using a method of geometrically expressing torque ripple. Furthermore, the effect of the proposed method of torque ripple reduction is confirmed by the experiment.