Novel control strategy of PWM rectifier

The operating characteristics of PWM rectifier in an unbalanced voltage supply is discussed based on study of the traditional control strategy of the three-phase voltage-type PWM rectifier in this paper. For the problems under unbalanced state, the novel control strategy that aims to suppress AC side negative-sequence current is proposed. The control system is divided into positive sequence and negative sequence symmetrical double closed-loop system and is controlled respectively. The simulation experiment verifies that the proposed strategy can effectively reduce the imbalance of AC-side current and the harmonics generated by rectifier and stabilize DC voltage, enabling the system to run efficiently, steadily and safely while the input voltages are unbalanced.