Research on the Control Strategy of DC-bus Voltage Double-Frequency Disturbance Rejection for Single-phase PWM Rectifier

In this paper, the state equation of DC bus voltage is derived by establishing the mathematical model of single-phase PWM rectifier. The results show that DC bus voltage is composed of DC component and double-frequency AC component. In order to suppress the double-frequency of the DC bus voltage, an adaptive state observer without delay is designed. The DC component of the DC bus voltage is extracted by the method of state estimation, so that the DC component and the double-frequency AC component of the DC bus voltage are separated. Only the extracted DC component is introduced into the control loop and the double-frequency voltage ripple is separated from the DC bus voltage control loop. Finally, a simulation model was built in Simulink platform to verify the effectiveness of the proposed method. The simulation results show that the proposed state observer can accurately extract the DC component of the DC bus voltage, eliminate the interference of double-frequency voltage ripple on the control system, and improve the dynamic response ability and stability of the system.