Variable-Speed Variable-Pitch Wind Power Generator Set LPV Gain Scheduling Control

Energy and environment are pressing problems that must be settled by human beings for future survival and development. As an important kind of generating form, wind power generation not merely can save the routine energy resources, but also may decrease pollution of the environment. Thus it can bring preferable economic benefits and community benefits. At resent, wind power generation has caused more and more attention by governments all around the world.Because of wind energy has lower density, instability and randomicity, wind turbines have strong nonlinear multivariable with many uncertain factors and disturbances. Therefore control is crucial to the efficiency and reliability of wind turbines. Compare with traditional control tactics, wind power generation system can gain satisfactory results with application of robust LPVH_∞gain scheduling control theory. Based on the megawatt wind tuthine generator system, the variable-speed variable-pitch control techniques and robust LPVH_∞gain scheduling control arithmetic for large scale wind turbine are deeply analyzed in this thesis.There are many control methods of wind power generator set, and various control technology has successful applied examples, however, with the content augment of wind turbine set, the control is more and more complex, especially much high demanding for dynamic stability of set. The routine traditional control technology (for example PID control) can't satisfy the requirements now. Aiming at the particularity of large wind power generator set, the paper puts forward a new robust LPVH_∞gain scheduling controller design method in order to resolve dynamic stability problems of set. Take use of LPV convex decomposition method, transform wind turbine model into convex polyhedron structure LPV model, and then by using LMI method design to meet H_∞performance and dynamic characteristic feedback gain for each vertex of convex polyhedron. Synthesize each vertex feedback gain to get LPV controller with convex polyhedron structure. The controller designed by this method depends on scheduling parameters, and can ensure a certain extent robust stability and robust performance in the range of parameters considered. Accoding to different wind speed condition, design respectively different robust LPVH_∞controllers in high and low wind speed field, and make simulation by MATLAB. Comparing the results with the PID controller, the output machine rotate speed in low wind speed field can track wind speed better, and improve the response time and dynamic stability in high wind speed field. Therefore, it validated that the controller has well control performance.