Improved Torque Ripple Reduction Method for Surface-Mounted Permanent Magnet Synchronous Motor in Flux-Weakening Region

An improved control scheme for surface mounted permanent magnet synchronous motor (PMSM) is proposed for the high-speed range operation with a torque ripple reduction. The onset of flux weakening is adjusted naturally by the outer duty cycle regulation loop to prevent the saturation of the current regulators. Meanwhile, the predictive q-axis current ripple is utilized to vary switching frequency pulse width modulation (VSFPWM) of the inverter. Hence, the maximum value of the torque ripple can be controlled. Simulation results have demonstrated the effectiveness of the proposed control strategy.