Research On Control Method Of Three-Phase PWM Rectifier Based On Hardware-in-the-Loop

Modern power electronics technology has been widely used in power systems,new energy systems and other industries.Owing to the high-power factor,bi-directional energy flow,low-current harmonics,and controllable dc-link voltage,The PWM rectifier truly realize the "green power conversion".Therefore,with the increasing demand of power quality,the research of PWM rectifier has become one of the hot topics at present.Firstly,the simulation model of PWM rectifier based on output DC voltage-input AC current double closed-loop control mode is established,which verifies the feasibility of this scheme.On this basis,the input AC current loop is improved.In view of the traditional controller’s narrow bandwidth and complex parameter setting,the deadbeat control method combined with SVDPWM is proposed.The delay problem of deadbeat control is improved by using advance prediction.By comparing the response speed of the two control algorithms in the D-axis current,the fast and accurate tracking of grid current is realized.At the same time,aiming at the problem that the DC side load change will affect the control accuracy of dc-link voltage,the extended state observer is used to observe the load current,and the feedforward compensation control method is used.By simulating and comparing the DC side voltage fluctuation between traditional control and the proposed algorithm under load disturbance,the robustness of DC bus voltage to load change is improved.Then,to reduce the cost and improve the reliability of the system,a control method of PWM rectifier with the voltage sensorless is adopted.The traditional sliding mode observer is improved.The fractional power function is used instead of the traditional switching function,and the resonant filter is combined.By comparing the control of traditional voltage sensorless observer with the proposed algorithm,the accuracy of grid voltage observation and accurate tracking of grid voltage phase information are realized.Finally,the semi-physical control system of the PWM rectifier control is designed based on the above improved algorithm,which mainly includes the hardware circuit design of the control board,the design of the software system,and the construction of the semi-physical platform,and the proposed algorithm is verified on the semi-physical experimental platform.