MECHANISM ANALYSIS AND PARAMETER TUNING OPTIMIZATION FOR WIND TURBINE TOWERS WITH PS-TMD PASSIVE CONTROL DEVICES

With the development of wind turbines in the direction of large megawatts, the high flexibility of wind turbine towers has been more and more obvious, and the vibration problem of the tower under operating loads such as winds, waves and earthquakes has become increasingly prominent. Aiming at the problems such as the complex loading of the wind turbine and the wide resonance frequency band, a new passive control device named the PS-TMD (Pre-stress Tuned Mass Damper) is proposed based on the special structure and vibration characteristics of wind turbines. Based on the principles of structural dynamics, a simplified mechanical calculation model of wind turbines with PS-TMDs is given. The dynamic coefficient and the branching point resonance frequency ratio are derived to analyze the vibration reduction mechanism of PS-TMDs. On this basis, the optimal frequency ratio, damping ratio and mass ratio of the system are derived. The optimal tuning of the system parameters is expounded theoretically. The numerical simulation of a wind turbine shows that the optimal frequency ratio of PS-TMDs reaches 0.9974, and its optimal damping ratio is only 0.35%. The PS-TMD damping system does not exhibit resonance divergence. The vibration reduction effect of PS-TMD can reach more than 60% near the natural vibration frequency of the structure. The finite element simulation results show that the control effect on the top displacement of the tower under the three different load cases can reach more than 35%, and that this device can effectively inhibit the resonance of the wind turbine tower.