摘要

Based on diode-assisted buck-boost inverter, this paper proposes a new commutation torque ripple suppression strategy for brushless dc motor (BLDCM). Four types of switching vectors are constructed, according to the working pattern of the diode-assisted inverter and the operation mode of the BLDCM. Moreover, the effects of switching vector combination on commutation torque ripple suppression and motor speed regulation are analyzed in the commutation and normal conduction periods, respectively. Based on this analysis, the duration of switching vectors within each modulation cycle is derived and the sequence of vectors is arranged at the same time in these two periods. The proposed method can effectively suppress the commutation torque ripple over the full speed range by unified switching vectors during the commutation period, without needing to switch control strategies according to the speed range. In addition, the increase of the voltage stress of switching devices in the inverter bridge can be avoided by designing the duration and sequence of switching vectors during the commutation and normal conduction periods. The effectiveness of the presented method is validated by the experimental results.