Commutation Analysis of Brushless DC Motor and Reducing Commutation Torque Ripple in the Two-Phase Stationary Frame

The control of brushless dc motors (BLDCMs) is similar to dc motors during the noncommutation interval. However, three phases are involved in electromechanical energy conversion during the commutation interval, making the control of the BLDCM similar to a three-phase ac motor during the commutation interval. A novel commutation analysis method for BLDCMs is proposed based on the coordinate transformation theory, which is used in control of a three-phase ac motor usually. The model of the BLDCM during the commutation interval is acquired in the two-phase stationary frame by using the Clark transformation. The commutation control method for suppressing commutation torque ripple and shortening the commutation time are obtained. Finally, the feasibility and effectiveness of the method is verified by experimental results.