Quadratic Optimal Tracking Control Of Wind Turbine System

As a kind of green and renewable resource, the wind power gets more and more attention of the world. It occupies an overwhelming position among the global renewable resources, which can be expected to become the main power source of Europe, Asia and North America in the future. But with the unpredictable and instability of the wind speed, the research of wind power control technology has become more and more attractive.First, we introduce the background and significance of the research. With the abundance of the wind energy content, our country has paid more attention on the development of the wind power to alleviate the energy crisis. But due to a late start, for large WT control technology, domestic always lags behind that of the European countries. This article introduces several popular control technologies in this field, with the comparison of their advantages and disadvantages.Second, it introduces the structure and the basic principle of wind power generation system of the variable-speed wind turbine, and establishes the mathematical model of the WT drive system. The WT system presents a strong nonlinearity because of the instability of the wind speed, which makes it hard for the control system design. As the characteristics of wind power utilization, this article makes research on the control of the wind turbine below the rated wind speed. The turbine can get the maximum power output with the rotor running at the desired speed. As the wind speed can’t measured in time, the aerodynamic part of the system is hard to be controlled which is greatly influenced by the wind speed.Third, In this paper, there introduces a robust control algorithm which can estimate the aerodynamic torque without measuring the wind speed, then the rotor runs at the desired speed to get the maximum power output. As robust controller may lose tracking precision and ignore the controller’s energy consumption for system stability, there introduces a LQ optimization algorithm to optimize the controller, which replaces somewhere of the former controller by the LQ controller. With the comparison of the simulation result of the controllers, it finds that the tracking result and the energy consumption of the controller getting a lot of optimization. The new controller achieves good control effect in the trace of the desired speed, which ensures the access of the maximum power below the rated wind speed.Finally, the results in this thesis are summarized and further work is also discussed.