Structural Control for an Offshore Wind Turbine with a Tuned Mass Damper in Floating Platform

Abstract

In recent years, offshore wind energy has become an attractive option due to the increased demand for the renewable energy. A method incorporating a tuned mass damper (TMD) in offshore wind turbine platform is proposed to demonstrate the improvement on structural dynamic performance in this investigation. The Lagrange's equations are applied to establish a limited degree-of-freedom (DOF) mathematical model for the barge-type offshore wind turbine. Genetic algorithm (GA) is then employed to find the globally optimum TMD design parameters. Numerical simulations based on FAST have been carried out to evaluate the effect of the passive control system. A changeable mass for the floating wind turbine will be brought for installing a heavy tuned mass damper in the platform. In this case, partial ballast is substituted for the equal mass of the tuned mass damper, and the vibration mitigation is simulated in five typical load cases. Results show that the passive control approaches can improve the dynamic responses of the barge-type wind turbine by placing a tuned mass damper in floating platform. Through replacing partial ballast with the equal mass of the tuned mass damper, a significant reduction of dynamic responses is also observed in simulation results for the barge-type floating structure.