The Study Of Three-phase Voltage Source PWM Rectifier Base On Direct Power Control

PWM rectifier because of its low harmonic content,energy can be two-way flow,the output voltage stability adjustable in a variety of converter devices,railways,power grids and daily life has been widely used.The advantages and disadvantages of the control algorithm have great influence on the dynamic response speed,steady state error and harmonic content of the whole system,so it has certain research value.The object of this paper is three-phase voltage-type PWM rectifier,the goal is to improve the current quality,improve system dynamic and static performance.Specific work includes:In the different coordinate system,the PWM rectifier is modeled and analyzed.The design method of the double ring is given.By decoupling the current,the problem of cross coupling between the current is solved and a double closed loop control system is established.The simulation model is established on the Simulink platform.The results show that the designed system has good dynamic and static performance,which provides the basis for the subsequent study of its control algorithm.Combined with the instantaneous power theory,a traditional direct power control(DPC)system is established in ?? coordinate system.The dynamic response of the algorithm is fast,but due to the non-linearity of the hysteresis comparator,and there is no definite switching frequency,the reactive power fluctuates greatly.Based on this,the model predictive control(MP-DPC)algorithm is applied to the direct power control.SVM is used instead of the switch vector table used in the traditional direct power,and the fixed frequency control is realized to solve the problem of difficult filter design.The simulation results show that the model predictive control not only retains the advantages of fast dynamic response,but also has the strong anti-interference and the adaptive ability to the load and the circuit parameter change.The direct power control system of the three-level PWM rectified fixed switching frequency is studied.The corresponding simulation model is established on the Simulink platform.The three-level SVM strategy is studied and the influence of each space vector on the midpoint potential is analyzed.The simulation results show that the direct power control algorithm is based on the instantaneous power theory,and the harmonic content is small and the anti-interference ability is strong under the same switching frequency compared with the direct current control.The hardware and software platform of three-phase voltage-based PWM rectifier is designed,and the selection method of inductance parameter is given,and a low-power experimental platform with TMS320F28335 DSP as the main controller is built.And the corresponding control algorithm is experimented to verify the feasibility and effectiveness of the algorithm.