Commutation torque ripple reduction in brushless DC motor drives using a single DC current sensor

This paper presents a comprehensive study result on reducing the commutation torque ripples generated in brushless DC motor drives with only a single DC-link current sensor provided in the inverter DC-link. In brushless DC motor drives equipped with only a single current sensor, it seems that commutation torque ripple suppression which is practically effective in low speed as well as high speed regions has not been reported. A proposed commutation compensation technique combined with a deadbeat DC-link current controller is based on a strategy that the current slopes of the incoming and the outgoing phases during the commutation interval can be equalized by a proper duty-ratio control. The proposed control method is verified through simulations and experiments.