Abstract. Based on the rotating coordinate system model, the mathematic analysis of the three-phase voltage-sourced PWM rectifier is carried out, and its feed-forward decoupling control strategy is studied. In order to realize the fast response of DC voltage and improve the dynamic and static performance of the rectifier, the double-closed-loop control of outer square of voltage loop and inner current loop is established. The control system of three-phase voltage-sourced PWM rectifier based on space vector modulation algorithm is designed. The simulation results demonstrate the designed model is accurate, and can achieve unity power factor control, DC voltage fast responses, and has not steady-state error.
IntroductionThree-phase voltage-sourced PWM rectifiers are widely used and researched due to numerous advantages, which can achieve small AC current distortion, controllable unit power factor, a constant output DC voltage, energy two-way flow and so on [1][2][3]. At present, the commonly used control strategies are mainly divided into voltage and current double closed-loop control, direct power control and the new control strategies based on control theory. The literature [4] proposed a direct voltage control algorithm ,the voltage error is a direct input control variable to realize the fast response of the voltage under the large disturbance of load, but the good control effect resulted from a more complicated algorithm . In the literature [5], the control strategy was put forward, which included slider mode control adopted in the outer voltage loop, the hybrid mode of decoupling current control without exact value of the boost inductor and internal model control was adopted in the current inner loop, and can achieve a fast dynamic response, good accuracy and stable output DC voltage in the case of inductance parameter variation. But the sliding mode control was not strongly sensitive to the input error of the model and the external destabilization. In the literature [6], the voltage outer sliding mode control was used. The inner loop combined the input and output linearization with space vector modulation, Which could transform the nonlinear control into quasi-linear control, realized the unit power factor control in harsh environment, and enhanced the robustness of the system. The literature [7] united the non-linear PI controller and decoupling current control without inductance L parameter, the new control strategy had a better control accuracy. Based on the research of domestic and foreign scholars, this paper analyzes the mathematical model of three-phase voltage-sourced PWM rectifier in static and dynamic coordinate system, and