Abstract: To solve the power circuit parameter design of the direct power control (DPC) system of three phase boost-type PWM rectifiers, the power control model of a PWM rectifier is established based on it model in the synchronouscoordinate. According to the power control model and the features of the DPC system of three phase boost-type PWM rectifiers, it is deduced that inductance on the AC side depends on power, the width of power hysteresis comparators, and switching average frequency. DC voltage is determined by AC voltage, inductance on the AC side, and load. DC capacitor relies on the pulsation of DC voltage, power, inductance on the AC side, and load. A design method of inductance on the AC side, DC voltage and DC capacitor of the power circuit based on many factors is proposed. The design method is proved feasible by simulation and experiment.