Excitation System For VSCF Double Fed Wind Power Generetor

In lately years, people widely pay attention to wind energy because it is a regenerated clean energy. It began development in high rate 20 years before. It is a fact that the variable-speed constant-frequency (VSCF) AC exited wind generator system is a main subject in the wind electric power generator schemes. It very fits for wind electric power generation with VSCF because it can capture as much energy as possible. Also AC exited generator have many excellent characteristics, it may improving the stability of electric power system, its rotor speed may adjustable, it has abilities for active and reactive power regulating in self-help ways, so it especially applied in wind electric power plant and pumped-storage hydraulic power plant.In this paper, based on the traditional wind power generation, the variable-speed constant-frequency generation technology is mainly researched, a comprehensive research on the DFIG with cage rotor used in the variable-speed constant-frequency wind power generation. The following items are included:1. The interrelated knowledge, developments and utilizations of wind energy are given and the state of wind power generation at home and abroad is introduced and some technologies in the world today are registered and the direction of wind power generation technology is forecasted in this paper.2. Analyses the work principle of AC excitation wind power generator as shift gears and constant frequency and deduces the mathematical model in a-b-c three-phase coordinate and d-q coordinate, and analyses the relation of electro-magnetism and energy balance.3. Research on the excitation style of simple generators. After studying the mathematical model in static three-phase coordinate and in rotary two-phase coordinate, the stator field-oriented vector control strategy is issued. It put forward and designed a dual PWM converter with the capacity of energy bidirectional flow. It also analyzed the basic theory and mathematical model of three-phase voltage source PWM rectifier.4. The core.device of the excitation system named SPWM frequency inverter is studied. Simulation results show that the converter can satisfy the demand of AC excited generation system, simulation and analyses of the whole system and control, strategy are carried through in matlab/simulink soft.The results indicate that the vector control AC excited generator has better dynamic performance and ensure the output voltage is constant frequency and constant voltage basically.