Application Research Of Fixed Mass Damper Vibration Reduction Technology In Wind Tower

The sustainable development of energy has become an important issue for energy development in all countries of the world.In recent years,wind power has been widely used as a clean energy source all over the world.Because wind power tower has been in a complex and changeable natural environment for a long time,wind or earthquake damage often occurs.How to effectively control the vibration of wind power tower has become a hot issue of research.The commonly used damping equipment is the tuned mass damper(TMD).However,due to the small space of the wind tower and the nacelle,it is difficult to place the mass unit,and the additional mass will increase the burden on the tower,which limits its application in flexible tower.This paper proposes a fixed mass damper(FMD)for tower vibration reduction,which changes the connection between the tower and the superstructure.Spring and damping unit are arranged between the nacelle and the tower,and upper structures such as nacelle and blade are used as mass elements to reduce tower vibration.Due to the softness of the connection,the basic period of the original wind turbine is greatly extended,which significantly reduces the influence of the high-order mode on the structure.In this paper,the vibration damping effect of FMD structure is analyzed by numerical simulation,and the structural connection design and parameter optimization method are proposed.The main research work is as follows:(1)The wind load flow field was established,and the two-way fluid-solid coupling analysis was carried out on the uncontrolled tower structure,TMD-tower structure and FMD-tower structure model.The dynamic response of the three structures under different wind conditions was studied.The analysis results show that the damping effect of FMD-tower structure under wind load is better than traditional TMD structure.(2)According to the idea of FMD vibration reduction,a dual-guideway energy dissipation device is designed.The two-way guideway is used to satisfy the braking between the upper structure of wind turbine and the tower,thereby the vibration control of the structure in the entire plane is achieved.Secondly,by comparing the frequency response curves of the uncontrolled structure and the simplified model of the FMD-tower structure,it can be seen that the FMD-tower structure has a significant drop in displacement and a slight increase in acceleration,which is similar to the increase in the acceleration response at the top of the tower in the simulation analysis.The design parameters of the FMD structure were analyzed.Finally,the parameters of FMD-tower structure are analyzed.The analysis results show that different structural parameters under wind load have different effects on the damping effect of FMD structure.When the frequency ratio is constant,the damping effect of the FMD structure gradually increases with the increase of the damping ratio,and finally tends to be stable.When the damping ratio is constant,as the frequency ratio increases,the damping effect increases gradually.When the frequency ratio exceeds a certain value,the damping effect decreases.(3)The key response values of FMD-structure under seismic loading are analyzed and compared.The analysis results show that FMD also has good effect under seismic load,but its influence on the damping effect is different from wind load.The parameter optimization formula of FMD-structure is deduced,and the structure has excellent vibration reduction effect under the optimized design parameters.