Vibration Control of Wind Turbine Towers with Inerter-Based Outrigger-Cable-Lever-Damping (IOCLD) Systems

Wind Turbine Towers (WTTs) are slender infrastructures for renewable energies, which are subjected to significant vibrations induced by wind and seismic hazards during their lifetime. In order to suppress these harmful vibrations, an Inerter-based Outrigger-Cable-Lever-Damping (IOCLD) system is proposed. It is composed of an outrigger, a lever, and a pair of cables and inerter-dashpot dampers. The outrigger is to convert bending rotation into vertical vibrations, which is transferred to the lever by the cables. The lever amplifies the inertial-damping force provided by the dampers. The inerter is beneficial to enhance energy dissipation. With these mechanisms, the vibration of WTTs can be effectively suppressed. In order to achieve optimal control performances, the tuning parameters of the IOCLD are analytically derived. Additionally, an equivalent inertance ratio is proposed to obtain the optimal parameters and evaluate the control performance. Finally, through practical numerical cases for wind- and seismic-induced vibration control, the effectiveness of the IOCLD is proved. Compared with existed Amplifying Damping Transfer System (ADTS) without inerters, IOCLD exhibits an excellent energy dissipation rate, which exceeds twice of ADTS for the investigated cases. Compared with conventional Tuned Mass Damper (TMD), IOCLD shows its advantages for lightweight, stability and in-situ adjustable feasibility.