The Wind Turbine Stability Control Based On Pole Place Method

In recent years technology of wind turbine develops rapidly, the capacity of wind turbine becomes larger and larger. The vibration problem of wind turbine also becomes more obvious and becomes the focus of research. The structure model of wind turbine plays an important role in wind turbine control or design process.In this paper, the state space of the structure vibration analysis and control under original coordinate and modal coordinate are summarized, the pole assignment method of single input single output system and multi-input and multi-output system are expounded; the controllability and observability theory of state space of the vibration system and State feedback control system and output feedback control system are introduced.To get the structure model, this paper starts with the mechanical structure of wind turbine, developing 2 node with 12 degree of freedom beam elements for the discretization of the blades and tower, establishes the models of the parts' respectively, then establishes the wind turbine model by combine the nacelle, tower and rotor into a whole system by substructure method, then uses the data of sut-1000 obtain the structure model and calculates the mode frequencies.In order to realize the model reduction of wind turbine system, mode orthogonal procedure the structural dynamics equations of wind turbine, then truncate the mode to reduce the degree of freedom of system. Furthermore, state equation of the wind turbine under mode coordinate is established, then the poles were placed using matlab software, and the calculate method of the actuator specific feedback force when placing pole were given.The bode diagrams of system of pre and post pole placing show that the results showed that radiolysis frequency response and phase frequency response near the original pole have been great improved. The simulation of wind turbine system before and after pole placing is carried out. Wind turbine on the pole placement of the vibration before and after the simulation, comparing the vibration fore-aft and lateral vibration of the top of the tower; and analyzed the influent of their corresponding first-order and second-order vibration modes on the vibration of themselves respectively. The results showed that after placing the poles, the vibration of the wind turbine has been a very good suppression.