A Simple Commutation Torque Ripple Reduction Method of BLDC Motors Using a Hybrid PWM Compensation

This paper presents an improved hybrid switching with voltage compensation function (VCF) to reduce torque ripple in commutating region and switching loss of a Brushless DC (BLDC) motor. In the proposed method, a modified 3-phase switching method is adopted to compensate the torque ripple in commutation region. Also, the conventional 2-phase switching method is used to reduce the switching loss during conduction. A simple VCF is designed to balance the slope of the outgoing and incoming phase currents during commutation. The designed VCF is added to the decreasing outgoing phase current to extend it during the built-up of the incoming phase current. Within a short commutation period, the proposed 3-phase switching method and VCF can reduce the commutation torque ripple. Total switching loss is dominantly determined by the conventional 2-phase switching method. The performance of the proposed control method is verified through experiment.