Commutation analysis and reducing torque ripple of Brushless DC motor based on the coordination transformation

The control of Brushless DC motor is similar to DC motors during the non-commutation interval, but three phases are involved in electromechanical energy conversion during commutation interval. A novel analysis method for Brushless DC motor is proposed by employing three-phase AC motor coordinate transformation theory. The model of BLDCM during commutation interval is acquired in the two-phase stationary frame by using Park transformation. The constraints for reducing commutation torque ripple and shortening commutation time are obtained. Finally, the feasibility and effectiveness of the method is verified by experimental results.