Torque ripple reduction technique with commutation time control for brushless DC motor

This paper proposes the reduction technique of commutation torque ripple in brushless DC motor drive. The proposed method modulates the current slope of the incoming phase and the outgoing phase in commutation interval respectively. These slopes can be modulated by using specific duty ratio during commutation. Since the proposed method controls the commutation interval, it does not require additional control loop and sensing circuit to acquire the interval. Hence, motor drive system can be achieved at a low cost with the proposed scheme. The motor drive scheme with the proposed technique is implemented by digital controller employed digital signal processor. The experimental results verify that the proposed method is valid and useful in reduction of commutation torque ripple.