A novel method based on delaying Hall signal for reducing torque ripple of brushless DC motor

This paper presents a novel method based on delaying Hall signal for reducing torque ripple of brushless DC motor. During the delayed interval, the back electromotive force (back-EMF) amplitude of outgoing phase declines and the phase current rises to stabilize phase voltage. The electromagnetic torque can remain steady by regulating the duty ratio. During the commutation interval, the time of outgoing phase current decays to zero is equivalent to the time of incoming phase current reaches stable value, which can derive the delayed time to minimize the commutation torque ripple. The method used in this paper with no need for any additional electrical devices, can obtain the delayed time under knowing the motor parameters. At last, the results of the simulation in MATLAB verify the correctness of the theories and the effectiveness of the proposed approach.