Integrated Dynamics Response Analysis for IEA 10-MW Spar Floating Offshore Wind Turbine

Wind energy in the deep-sea area is more abundant and the capacity of wind turbines can be made larger. Therefore, the research on deep-sea floating offshore wind turbines will be the primary strategy for wind energy exploitation in the future. The spar-type platform depends on the characteristics of a small water plane, deep draft, and good stability, which has been applied to the commercial development of deep-sea wind energy. In the next ten years, the 10-MW wind turbine will become the mainstream class installed in the floating offshore wind turbine farm. Thus, it is very necessary to conduct a comprehensive and in-depth study on the 10-MW spar type floating offshore wind turbine. The direct-drive 10-MW offshore wind turbine was proposed by the International Energy Agency (IEA) in Wind Task 37 in 2019. In this paper, a spar-type platform is designed to support the IEA 10-MW reference wind turbines, and a nonlinear aero-hydro-servo-elastic numerical model is established using the FAST tool (which is developed by the National Renewable Energy Laboratory, NREL). Then, the accuracy of the wind turbine and the sensitivity of the controller are verified, and the natural periods of the floating offshore wind turbine are obtained by free-decay tests. The natural periods of the platform in six degrees-of-freedom are found to be within the range recommended by the design standard. The measured wind and wave data of the target site close to Fujian Province of China are used to evaluate the performance of the floating offshore wind turbine under the 100-, 50-, 5-, and 2-year-return stochastic weather conditions. The results indicate that the design of the spar platform is reasonable and has excellent hydrodynamic performance.