The Research Of Three-phase PWM Rectifier Based On The LLCL Filter

Three-phase PWM rectifier is an important power electronic converter device, it has some significant advan tages, such as cons tant output voltage, high power factor, power two-way flow, compared with the traditional diode rectifier. A three-phase PWM rectifier system based on LLCL filter is studied in this paper.Firstly, this paper constructed a mathematical model of three-phase PWM rectifier at the three-phase stationary coordinates. Then dedu ced the model at two-phase rotating coordinate system. Also introduced the SVPWM technology and explain how to achieve it.Secondly, it using LLCL filter replace the L filter to reduce inductance. LLCL filter is the third-order objects, so is dif ficult to design. A fter detailed analysis of the LLCL filter, this paper made a LLCL filter parameter design method.Thirdly, on the basis of three-phase PW M rectifier model, this paper using the voltage vector control strategy design the voltage closed loop and the current closed loop. In order to improve the accuracy of the current, it using a complex control structure which combined the PI control with the repeat control. In the co mplex control structure, PI control is used to obtain better dynamic response, repeatitive control is used to reduce the static error.Finally, this paper using Matlab/Simulink construct the three-phase PWM rectifier model. Through the simulation results, it can prove the design of LLCL filter and the complex control strategy is corre ct. Then this paper build the control core and establ ish the experim ental platform. The experimental results show the correctness of this paper’s theory.