A modified direct torque control method of brushless DC motor based on hyper space vector modulation

Direct torque control of brushless DC motor (BLDC) is complex for turn-off phase. And the direct torque control of brushless DC motor based on hyper space vector solved the problem, however, the torque ripple was obvious. A modified method is presented in this paper in order to reduce the torque ripple based on hyper space vector. For the turn-off phase only affects the stator flux linkage but not the torque, the torque ripple can be reduced significantly by the modulation of two new voltage vectors in each sector on abc plane. The new modulation method can form more voltage vectors in one control period. The analysis is verified by simulation results.