A new method to reduce both conduction and commutation torque ripple for BLDC machines

To reduce torque ripple of BLDC machines, a method using the new DC-DC converter is proposed in this paper. The converter can switch its output to low or high voltage. The adjustable low voltage is used to regulate the motor speed, which can replace the switch chopping control for the inverter to reduce the conduction torque ripple. And the adjustable high voltage is used in commutation period to compensate the commutation torque decline. Both of the conduction and the commutation torque ripple can be suppressed simultaneously is the advantage of this method.