Pulsewidth Modulation Technique for BLDCM Drives to Reduce Commutation Torque Ripple Without Calculation of Commutation Time

This paper presents a three-phase pulsewidth modulation (PWM) technique for brushless dc motor (BLDCM) drives to reduce the commutation torque ripple. As compared to previous approaches, the presented technique does not require any torque observer and calculation of commutation time which may be sensitive to motor parameters and may require more calculation time. The commutation time for the presented technique is determined by a detection circuit which consists of simple comparator circuit. The experimental results derived from a field programmable gate array based controlled BLDCM drive show that the commutation current ripple can be significantly reduced by the presented PWM technique.