A New Method to Minimize Overall Torque Ripple in the Presence of Phase Current Shift Error for Three-Phase BLDC Motor Drive

Torque ripple is always problematic in brushless dc (BLDC) motor drive. It is caused by nonsymmetric commutating phase current rate and phase current shift error. The latter is inevitable even in the latest sensor/sensorless BLDC motor control and drive. In this paper, a simple, robust, and low-cost method of minimizing overall torque ripple in the presence of phase current shift error is presented. It works and manages well to maintain the torque ripple increase within 10% even with 27° phase current shift, compared with more than 25% torque ripple increase without any compensator. The proposed technique is theoretically elucidated in detail, and the performance is verified via MATLAB/Simulink simulation and experiments.