Research On Direct Power Control Of Grid-connected Converter For Wind Power Generation System

Energy and the environment are the urgent problems that human beings exist and development nowadays. Wind power has attracted more and more highly attention as one kind of clean regenerative energy sources. This dissertation is a part of the project of developing 1.5MW Wind Power Generation Energy Conversion System which applied to the variable speed constant frequency wind energy system (VSCF). The focus is on the control method of grid-connected converter in the electrical energy conversion system.This dissertation summarizes the art-of-the-state of wind power generation and compares the predominant technologies. This dissertation refers to the 1.5MW Wind Power Generation utilizes the AC-DC-AC conversion configuration to deliver the high-level power energy from permanent-magnet generators to the grid having more developing forefront. The grid-connected converter in high-power wind power generation system has the topology of three phase voltage source PWM rectifier. The paper is mainly about the control system in principle analyzing, simulation and experiment validating.The topology, operation principle and mathematical modeling of PWM rectifier are discussed. Aim at the disadvantage of traditional power definition, the dissertation analysed instantaneous power theory of three phase circuit and designed direct power control (DPC) system. The control system includes inner power control loop and outer DC voltage loop. In order to attain unity power factor, the reactive power reference initialized zero. The DPC system is researched by simulation model based on MATLAB/SIMULINK and get the results.The high speed integrated control chip DSP is the core of PWM rectifier control, following designing the hardware circuits and DSP program of the DPC system. The program includes main, interrupt subroutine, protecting, PI and in-phase program. The DPC system experiment accomplished in low-power PWM rectifier system and adjusted the control parameter during the experimentation.At the mean time, the experimrntal waveforms are presented and analyzed in the end of the paper. The experimrntal result indicates that DPC system has the advantage of high power factor, high efficiency, simple arithmetic and system composing, better dynamic response and so on. So DPC adapts to apply in high-power wind power generation system.