Commutation torque ripple suppression strategy for brushless DC motors with commutation time in multiples of PWM period

摘要

In this paper, a commutation torque ripple suppression strategy is proposed with commutation time in multiples of PWM period. Firstly, the commutation time of different modulation strategies required to suppress commutation torque ripple is analyzed, and the main factors that influence commutation time are pointed out. Then, according to the shortest commutation time, the non-commutation phase modulation strategy is selected, and the dc voltage is adjusted by the boost converter to suppress commutation torque ripple over the full speed. Moreover, since the commutation time that is not integer multiples of the PWM period affects the commutation torque ripple suppression effect seriously, a voltage regulation mechanism of the boost converter is further designed. By this regulation mechanism, the commutation time can be controlled to the minimum integer multiples of the PWM period, and no additional circuits or control loops are required for detecting the commutation time. Finally, the correctness of the analysis and the effectiveness of the presented method are validated by the experimental results.