The Research And Design Of Three-Level PWM Rectifier

Compared with the traditional diode rectifier, the PWM rectifier has many advantages such as grid-free pollution, adjustable power factor, so an ever-enhanced attention had been focused to the PWM rectifier in the field of power electronics. And in the high power situations, three-level topology structure has a strong competitive advantage both from practicality and the control of complexity, so the three-level structure of the PWM rectifier has got more and more attention and research.The three-level diode clamped PWM rectifier is the main research object in this paper. The basic principles and four-quadrant operation state of the PWM rectifier has been researched and in-depth analysis. The main circuit of the three-level diode clamped PWM rectifier topology structure is demonstrated, and whose mathematical model in different coordinate system is derived. An easy programming of the simplified SVPWM modulation algorithm is designed on the basis of the analysis of the traditional SVPWM modulation algorithm.In this paper, a digital PLL system is designed to obtain the phase angle of grid. The dual-loop control system of PWM rectifier is in-depth researched; the voltage loop and inner current loop are designed with the tuning method of best engineering. For non-linear characteristics of the three-level PWM rectifier, the precise mathematical model is difficult to obtain. In order to improve the system dynamic and static performance, a fuzzy adaptive PI controller is designed to modify the parameters online. In Matlab/Simulink simulation environment, a three-level PWM rectifier control system is built and the simulation results ware analyzed.At last, this paper designed an experimental system to the TMS320F28335as the core. The hardware and software design of the experimental system is analyzed, the correctness and feasibility of the control strategy is verified by the PWM rectifier experiment and energy feed back experiment.