As we all know, when the harmonic component of the current is smaller, the torque ripple of the PMSM control system is better. When the current THD is within 10% it is acceptable, referencing practical engineering applications. Therefore, the analysis of the current THD is an important factor for reducing torque ripple of the PMSM control system.
And according to mechanical motion equation of the motor, the output of the speed is obtained by the torque through the low-pass filter, whose cut-off frequency is B/J. If the frequency of the torque ripple is higher than that of the low-pass filter, the motor can obtain relatively satisfactory speed regulation performance even through the torque ripple exists. In addition, the focus of this paper is to ensure that the anti-disturbance could be achieved with the very low overshoot, the high-accuracy, and high-stability of the speed performance simultaneously. The current distortion and torque ripple of the PMSM control system would be the next focus point of future research.