Analysis and Suppression of DC Bus Voltage Ripple of Cascade Brushless DC Motor Drive System

This paper introduces a cascade brushless DC motor drive system based on buck converter. In such cascade system, the commutation of BLDCM is equivalent to a sudden load change to the buck converter, which will cause the DC bus voltage ripple especially in high power occasion. Relevant studies on the DC bus voltage ripple suppression are given first, but there is rare study providing a proper drive method for BLDCM with a buck converter. Then, a detailed theoretical analysis is provided, and meanwhile a novel drive method based on the hybrid approach combining overlapping commutation and predictive current control (PCC) is proposed. Through adding PWM generated by PCC to the out-going phase to suppress the pumping voltage. Simulation results show the feasibility and effectiveness of the proposed method.