Commutation Torque-ripple Minimization for Brushless DC Motor Based on Quasi-Z-Source Inverter

Abstract

Conventional brushless DC Motor (BLDCM) drive involves a voltage-source inverter with six-step squarewave control, which can be widely used in automated industrial applications. However, high torque ripple due to different current slew rates during the commutation interval would significantly reduce the performance in the high-precision area. To tackle this problem, the paper proposes a novel strategy to reduce the commutation torque-ripple by using a quasi-Z-source inverter. In which, an impedance network is implemented between the power supply and the voltage-source inverter. This could make the equivalent DC-link voltage boosted during the commutation interval to compensate the current dip of commutation phase, and keep incoming and outgoing phase current changing at the same rate. In Matlab/Simulink environment, proposed scheme is developed and simulated. Finally, the effectiveness of the proposed control strategy is validated, the torque ripple can be greatly reduced and with the increased average torque.