The Active Flow Control Of Hige-Aspect-Ratio Wind Turbine Blade Based On Trailing-Edge Flaps

In recent years, the wind turbine blades are continuously increasing to get the more power conversion efficiency. High-aspect-ratio wind turbine blade is a slender flexible body. The force and deformation are extremely complicated with the effects of aero-elastic coupling. How to reduce vibration and increase the capture of the wind under the complex interaction by flow control techniques is a key problem. Focusing on this problem,the research work of this paper has been done as follows:Firstly, based on the specific parameters of the existing 2.5MW wind turbine, the solid model of the blade was established in Pro/E software. The modal analysis of the blade was carried out, and the first six-order vibration mode of the blade were solved in the ANSYS Workbench software. The main vibration forms and the corresponding vibration frequencies were obtained.Secondly, the elastic model of the blade was established according to the Rayleigh-Ritz method, and its aerodynamic elastic model was established by coupling the Theodorsen unsteady slice theory. The motion differential equation was deduced by the Lagrange equation,and then the differential equation of motion was transformed to obtain its state space equation,and the correctness of the control equation were proved indirectly.Thirdly, after the control goals of the control system set, this paper selected the Model Predictive Control(MPC) as control strategy. Then, the simulation was carried out by MAILAB software. The simulation results show that the control surfaces can effectively reduce waving and torsional vibration under the control of the MPC algorithm and return to steady state quickly in case of sudden disturbance. We can conclude that the angle of attack can track the desired output signal quickly and accurately to realize the local adjustment of the large-scale wind turbine blade. It can improve the wind capture with the pitch system.Finally, the distributed trailing-edge flap control surface has redundant characteristics. The fault tolerance for the control goals of the control surface was simulated. The simulation results show that when the control surface appears faulty, the control system has good tolerance to damping effect, but it will affect the control angle tracking in a certain range. The control surface changes the aerodynamic characteristics at the installation position. Reducing the installation range and adding the number of trailing-edge flaps may increase the control accuracy of the blade.