Design And Research Of Three-phase Voltage Source PWM Rectifier

Traditional diode uncontrolled rectification has the problems of high harmonic content of grid-side current and low system power factor etc.,significantly deteriorating the quality of the power grid,and has attracted widespread attention to the power factor correction of grid-side current.The PWM rectifier has merits of sinusoidal input current at the AC side,the same phase of current and voltage(unit power factor),fast dynamic response at the DC side,and four-quadrant operation,which can effectively reduce power loss and improve grid efficiency.Based on this,this paper systematically investigates the three-phase voltage source PWM rectifier by means of both simulation and experiment.This present work analyzes the topology,working principle and control mode of PWM rectifier in detail.Firstly,the topological structure classification of PWM rectifier is systemically introduced,and then the mathematical models of the rectifier are established.The double closed-loop control of voltage outer loop and current inner loop is selected as the control mode of PWM rectifier.According to the engineering experience,the PI parameters of the regulator are determined,and the decoupling of DQ axis is realized by feedforward decoupling control.In addition,the modulation mode is investigated,and the principle and implementation process of SVPWM modulation mode are introduced in detail.The SVPWM modulation mode is selected.Meanwhile,the phase locked loop technology can quickly and accurately determine the grid side voltage phase,eliminate the influence of grid-side voltage asymmetry and grid-side phase estimation,and improve the reliability of rectifier operation.At last,according to the design requirements,the main circuit parameters are derived in detail including the filter inductance value at the AC side and voltage stabilizing capacitance value at the DC side.This would provide a theoretical basis for the production of the experimental prototype.Before the prototype is built,the system model is simulated by Matlab/Simulink to verify whether the circuit model and the selected circuit parameters are correct.The simulation calculation of each module of the system is carried out,and found that the simulation result of each module is consistent with the theoretical result.Furthermore,the complete voltage-type PWM rectifier circuit is simulated,and it is found that the output DC voltage is stable and adjustable,and the input AC side voltage and current phase are the same,verifying the correctness of the theoretical analysis.On this basis,the hardware and software of the system are designed,and the experimental prototype is completed.The experimental results show that the designed PWM rectifier can fulfil the performance requirements.