| Three-phase PWM rectifiers have been widely used in active power filtering,new energy grid connection,microgrid system,HVDC due to these advantages,such as unity power factor,low harmonics distortion of the line current,DC-link voltage controlled,bidirectional energy flow,and so on.With the vigorous development of power electronics technology and devices,more stringent requirements have been imposed on the dynamic response capacity and steadystate control performance of three-phase PWM rectifiers to satisfy the increasing demand for power quality in production and life.Therefore,the research on the control algorithm of threephase PWM rectifier is of great theoretical significance and practical engineering application value.In order to improve the dynamic response speed and control accuracy,to achieve the unity power factor,reduce the hardware cost and complexity of three-phase PWM rectifiers.this paper focuses on the research of direct power control algorithm,model prediction power control algorithm,online identification of inductance parameters,and the control algorithm without grid vltage sensor.And the specific contents are shown as follows:First of all,according to the model circuit of the PWM rectifier,the working principle of PWM rectifier in different operating states is analyzed in detail.and their mathematical model in the abc three-phase stationary coordinate system,two-phase alpha-beta stationary frame and two-phase d-q rotation frame are established,Meanwhile,the basic principles of SVPWM technology are analyzed.Secondly,the operating principle of the conventional direct power control(DPC)based on proportional integral(PI)controller and finite-control-set model predictive power control(FCS-MPPC)are analyzed.Then,from the dynamic component optimization point of view,this paper applies the cost function used in model predictive control to predict an optimal dynamic component of input voltage and a model predictive power control(MPPC)with dynamic component optimization of the input port voltage is proposed in this paper to overcome the drawbacks of complicated parameters design,slow dynamic response in PIDPC and high current harmonics distortion,unstable switching frequency in FCS-MPPC.In addition,the proposed MPPC algorithm is sensitive to inductance parameter,the effect on system power is analyzed when the control inductance parameters are mismatched with the actual inductance parameters.On basis of this,an online inductance identification method is proposed,which can effectively identify the inductance parameter and achieve unit power factor.Meanwhile,compared with the PI-DPC,FCS-MPPC,the proposed MPPC and the online identification method of inductance parameters are verified respectively by simulation.Then,for the sake of reducing the hardware cost and complexity of the system and avoid the impact of the fault of the line voltage sensor on the system control performance,the control without line voltage sensor for the PWM rectifier is studied.Then,in order to eliminate the error of the amplitude and phase of the virtual flux obtained by the traditional virtual flux observer,a control strategy without line voltage sensor based on improved virtual flux observer is proposed.Meanwhile,this algorithm can effectively eliminate the error caused by the filter,and the algorithm is verified in computer simulations.Finally,a hardware-in-the-loop experimental platform with the RT-LAB and the TMS320F28335 DSP digital controller is briefly introduced.An experimental tests of the traditional PI-DPC and the porposed MPPC strategy are verified.The experimental results proved the correctness and effectiveness of the proposed algorithms.What’s more,the online identification method of inductance parameters and the control algorithm without line voltage sensor based on improved virtual flux observer are also tested experimentally. |
