Mitigation of vibrations and its optimization in a large floating wind turbine across different typhoon stages

Typhoon disasters challenge the development of offshore wind power in typhoon-prone areas, particularly in Chinese water, as existing standards inadequately address turbine requirements under extreme conditions, leading to vibration issues that limit deep-water deployment. This study develops a fully coupled aero-hydro-servo-elastic-mooring model for the NREL 15 MW semi-submersible floating wind turbine with Tuned Mass Damper (TMD) control, using Typhoon Rammasun as a representative case to assess the impact of different phases on 3D pulsating wind field simulations. The dynamic response of the NREL 15 MW semi-submersible floating wind turbine under various TMD controls and stages of Typhoon Rammasun was studied. A TMD parameter optimization framework using OpenFAST, MATLAB, and NSGA-II algorithm was proposed. Results show that Pitch-TMD reduces pitch response by 9.5 % and fore-aft bending moment by 4.7 % under eyewall conditions (wind speeds >70 m/s). Optimized Pitch-TMD parameters further reduced pitch and roll by 6 % and 11.8 %, and bending moment by 2.1 %. Notably, the turbine in shutdown mode in the outer vortex region exhibited smaller responses than during normal operation within the typhoon eye. Additionally, Extreme typhoon mooring line design should consider wind-wave alignment impacts.