Study On Mitigation Of Wind Turbine Structure Vibration Using Bidirectional Tuned Mass Damper

After entering the 21 st century,the environmental pollution caused by fossil energy becomes more and more serious.The development and utilization of clean energy such as wind energy and solar energy have become an important direction of energy development in the new era.As the main development measure of wind energy,wind power generation has been listed in the important national energy production planning because of its strong capacity continuity and small cultivated land occupation.In order to capture more wind energy,the size of wind turbine structure is getting larger and larger,the structure becomes more and more flexible,the sensitivity to horizontal load is increasing,and the vibration is becoming more and more obvious,which leads to more and more serious damage problems such as structural strength and fatigue.Therefore,this study proposes a bidirection tuned mass damper(TMD)to reduce the dynamic response of wind turbine structure under earthquake and wind load,and reduce the vibration and fatigue of the structure.Taking a 2.5MW wind turbine structure as the research object,through numerical simulation and shaking table test,the vibration control of the wind turbine structure adopting the bidirectional TMD under the action of earthquake and wind load is studied.The main research contents include the following aspects:(1)By using ANSYS finite element software,a lumped mass model and a bladetower model considering the coupling effect of blade and tower structure are established.In the lumped mass model,the nacelle,hub and blade are equivalent to mass points connected on the top of tower structure,the blade-tower model is equivalent to variable section beam,and the nacelle is equivalent to a beam,which is used to connect blade and tower.The dynamic characteristics of the two models are compared and analyzed to lay a foundation for the subsequent analysis and calculation(2)According to the characteristics of wind turbine structure,and based on the TMD Control Theory,a directional TMD device suitable for wind turbine structure is proposed.The optimal parameter relationship of bidirection TMD is obtained by minimizing the displacement amplification coefficient.After analyzing the basic dynamic characteristics of wind turbine structure,the key mechanical parameters of bidirectional TMD device are calculated according to the dynamic parameters of wind turbine structure.(3)A wind turbine structure model with bidirectional TMD is established.The influence of different mass ratio of TMD on the vibration reduction control efficiency of wind turbine structure under the action of one-way and two-way earthquakes is considered.The dynamic response and vibration reduction efficiency of the two models are compared.The results show that the dynamic response of wind turbine structure decreases,and the control efficiency in one-way and two-way increases with the increase of mass ratio.It is found that when the frequency of wind turbine structure increases,the damping efficiency of bidirectional TMD increases first and then decreases.When the frequency of wind turbine structure decreases,the damping efficiency of TMD becomes smaller and smaller.(4)Based on Davenport spectrum,the wind speeds of time-history at rated wind speed and cut-out wind speed are generated,and the blade load is calculated by the theory of blade momentum.Combined with the consideration of various working conditions of wind turbine structure,the dynamic time history analysis of wind turbine structure is carried out,and the response changes of wind turbine structure under the action of wind load and the control efficiency of TMD to response are analyzed after the installation of two-way TMD.The results show that under the action of wind load,the control effect of bidirectional TMD on the top bending moment of blade tower model is poor,and it has good control effect on other responses of two kinds of wind turbine structure models.(5)The scale research model of the response control of the wind turbine structure under the earthquake action is designed.The shaking table test of the vibration reduction effect of the device on the wind turbine structure under the earthquake action is carried out.The test result shows after the installation of the device,the wind turbine structure can achieve two directions of shock absorption under different earthquake incidence angles,which provides reference for the shock absorption of wind turbine structure.The result shows that the bidirectional TMD device has a better damping effect on the response of wind turbine structures under different earthquake intensities.