A control strategy of three-phase boost type PWM rectifier based on virtual flux

This paper introduces the model of PWM rectifier by regarding the AC side as a virtual motor, and presents the estimation method of AC voltage, virtual flux and instantaneous active/reactive power. It is now well known that the switching table is the most important for PWM rectifier. The traditional switching table in power loop of DPC system controls instantaneous active and inactive power, leading to the dynamic voltage drop during load current disturbance. This paper presents another direct power control strategy based on alternate choosing and using the instantaneous active and inactive power switching tables. Thus, good transient performances of PWM rectifier are obtained. The capacity of resisting load current disturbance is increased and stable voltage drop is eliminated by the duty cycle of square wave to control double switching table based on load current feedback. Moreover, this method is verified by simulation to be suitable for PWM rectifier control strategy.