Research On Adaptive Control Of Large-scale Wind Turbines With Stochastic Disturbances

Along with the traditional energy resources, especially fossil energy has attracted more and more environmental problems, and because of its non-renewable, the problem of scarce resources in the future will become more and more obvious. In recent years, in order to meet the growing demand for energy, renewable energy has been rapid development and application. Among them, because wind energy has the advantages of low cost, huge reserves etc. Its development is also faster and more mature in new energy. However, with the installed capacity and the increasing capacity of unit are increasing year by year, which puts forward higher challenge for the control system of wind power generator. Because the wind itself has the stochastic properties and uncertainty, large-scale wind turbines use traditional control methods can’t achieve the desired control effect. While most previous studies to establish the ideal situation, this paper analyzes the wind stochastic properties, using robust adaptive control theory to solve the wind turbines at stochastic perturbations environment stability problems.First of all, the aerodynamics of wind machine and the main control technologies are discussed, the structure and characteristic of large-scale wind turbine is introduced in detail, on the basis of this, the operation process of the wind turbine are analyzed. And then combined with the stochastic process, introduces the concept of stochastic system, expounds the differences of stochastic system and common system, used for stochastic analysis of the Ito formula to do the full proof.Secondly, fully considering the stochastic properties of the wind turbine, the wind turbine is modeled mathematically under stochastic differential equation. Robust adaptive control algorithm applied to achieve a robust and adaptive control effect, the elimination of the system parameter uncertainty and stochastic disturbances have very good results.Finally, in order to optimize the operation efficiency of the variable speed wind turbine, maximize the energy captured from the wind and minimize the fatigue load and power fluctuations generated by turbulence, a linear quadratic Gaussian control strategy based on extended Kalman filter is proposed. In this control strategy the mean effective wind speed is selected as the gain schedule variable. The parameter of the controller can change adaptively according to the wind turbine operation points so that the optimal control can be realized at each operation point.This thesis is supported by National key basic research development plan(2012CB215202) and National Natural Science Foundation of China(51207007).