The research on three-phase PWM rectifier at low switching frequency under disturbance

Abstract

The traditional three-phase PWM rectifier at the relatively high switch frequency can obtain good dynamic performance, such as good dynamics of DC bus voltage under disturbance, using the control strategy of load current feed-forward. However, the traditional form of load current feed-forward controller should be modified when switching frequency is relatively low, because complex state variables controller take place the PI controller in this circumstance. To deal with this problem, this paper, first, use mathematical modeling to describe PWM rectifier, and then analyze the reasons of utilizing complex state variables current controller at low switching frequency instead of PI controller. On this basis, a novel scheme is proposed to inhibit DC bus voltage disturbance for PWM rectifier.