Passive structural vibration control of a monopile wind turbine tower

Offshore wind turbines suffer from severe wind and wave conditions which generate heavy fluctuating loads and vibrations leading to fatigue of turbine towers. We employ tuned mass dampers (TMDs) as passive structural vibration control method to reduce fluctuating loads acting on the tower. We obtain a discretized state space model from the coupled non-uniform NASA SCOLE (Spacecraft Control Laboratory Experiment) and TMD system, which represents a monopile wind turbine tower with a TMD system atop it, using spectral element method. The parameters of the TMD are optimized by minimizing the frequency-limited ℋ ₂ norm of the transfer function of the discretized state space model with force and torque as inputs and tower-top displacement as output. In addition to control design, our model can also be used for fast & accurate simulation for the dynamics of the wind turbine tower. Other advantages of our model and method over previous work are also analyzed. Verifications are conducted against FAST (Fatigue, Aerodynamics, Structures, and Turbulence) simulation.