Reference frame approach for torque ripple minimization of BLDCM over wide speed range including cogging torque

Torque ripple control of brushless DC motor has been the main issue of servo drive systems in which the speed fluctuation, vibration and acoustic noise should be minimized. In this paper, the novel approach to achieve ripple-free torque control with maximum efficiency based on the d-q-0 reference frame is presented. The proposed method optimizes the reference phase current waveforms including even the case of 3 phase unbalanced condition. As a result, the proposed approach provides a simple and clear way to obtain the optimal motor excitation currents. The validity and practical applications of the proposed control scheme are verified through the simulations and experimental results.