Study On Three-phase Four-bridge PWM Rectifier Based On One-cycle Control

In recent years the electronic technic grows faster and faster, more and more electronic achievements have been used into different fields with the consequences that the electronic equipment has become one of the main fact that causes the harmonic pollution in the grid. Three-phase rectifier is widely used to connect the lord and the grid, so put research on it and improve the power factor and reduce the harmonic pollution has significant mean.Firstly, this thesis introduces the main methods and topologies that used nowadays, and choses three-phase PWM rectifier with one-cycle control as the research object. The system has three tasks: correct the power factor, control the DC voltage, control the neutral current. Considering about the compatibility and safety of the case, the equalizing bridge is designed to guarantee the balance of three-level output no matter with the neutral line or not.Then the thesis analyzes the operating mode of both the PFC part and the equalizing bridge part, deduces the equations of four line state and three line state. The simulation proves the equivalence of the two states. Take the inductor voltage into concern when the frequency ratio between switch and input is low. After that the system small signal model is made based on the rotating coordinates which can serve the procedure of parameter designing of the control system.Finally, the parameter of main topology is determined according to the input and output, and the compensation of the control system is designed by the single neuron control strategy according to the small signal model. The simulation runs on MATLAB / simulink proves the three-phase PWM rectifier with one-cycle control proposed in this thesis can do with both four-wire state and three-wire state. It has the performances of low THD and high power factor, which contain well stability and dynamic tracking.