A Study Of AC-excited Wind Power Generation System And Its Controlling Scheme

21^st Century will be the quick development stage of renewable energy . Statistic indicates that the utilization of chemical energy source will decline in recent years, yet the utilization of renewable energy source will mount up. Men of insight predict the lately 20-30 years will be a development peak of the renewable energy. As the most important kind of wind utilization, wind power generation have a bright future.In the exordium, the paper introduced the development status and retrospect the general situation of wind power generation in our country , gave out the paper's main content and investigation significance. The principal of this paper part introduced the AC-excited technique for wind power generation. First, The specialty of the AC-excited generator was presented and the difference between the synchrony generator, asynchrony generator and the AC-excited generator was pointed out. This paper analyzed the fundamental for variable speed constant-frequency of the AC-excited generator. The operation region of the AC-excited generator was divided into three segments, and the control scheme for pursuing max wind power in the part of constant C_p was discussed.The paper analyzed the mathematic model of the AC excited generator on a-b-c coordinate system . Transform of coordinates was adopted against this model's nonlinearity and coupling. After the discussion of the transform of coordinates, the thesis deduced the mathematic model on the d-q coordinate system. Furthermore, this article simplified the d-q coordinate model by the stator flux oriented vector control method .The frame of the vector control system was build on the base of the model on d-q coordinate system .Simulation models of all parts of the whole control system were build in Matlab/Simulinko Using the stator active power computed from the maximal output power of the wind turbine as the reference value of vector control system, the result of experiment approves that the control strategy is correct . Not only the frequency of stator current is constant, but the control of stator active and reactive are decoupled, and the output power tracks the maximal power of wind turbine .