Research on torque ripple suppression of position sensorless brushless DC motor during commutation

Position sensorless PM brushless DC motor generates pilsating current in the course of nature commutation, which causes torque ripple. In order to reduce the torque ripple, the current during commutation is controlled by certain methods which need current sensors usually. This paper proposed a novel and low cost method which can reduce torque ripple by changing the duty cycle during comutation. Experimental results show that this method is easily used to reduce the pulsating current and torque ripple during comutation without current sensors.