Adaptive Load Reducing Control And Load Monitoring For Floating Wind Turbines

With rapid growth of wind power capacity all over the world since this new era,onshore wind farms have approached to saturation gradually.In contrast,the development of offshore wind power has a further prospect.Based on review of advanced technology on international wind power industry,and learned from other established techniques,the load reduction control method for floating wind turbines was researched in this paper.Due to many advantages including great potentials of wind energy resources in the deep sea,relatively small environmental impact and less land resources the resources of occupied,floating wind turbine as one effective means to develop wind energy of deep sea has become a research focus.However,floating offshore wind turbines are facing with a series of technical problems such as parameters uncertainties,external environment complexity,wind waves,and the coupling effect which pose challenges to the normal operation of the system.Therefore,one of effective methods is that to reduce structural load of the wind turbine and maintain its stability.The active structure control method and multi-stage control technology for wind turbine come into being.The two methods can effectively reduce pitching movement of the floating offshore wind turbines,which not only reduce the load,but also provide an effective operating environment.In addition,in order to better monitor the load state of the wind turbine,it is valuable.To design the man-machine interface of the offshore floating wind turbine for whole system online monitoring.In this thesis,the active load control methods for floating wind turbines are studied in depth.The main work of this thesis is summarized as follows:(1)The problems of floating wind turbines structure,operating environment,and fluid and aerodynamics are studied.By analyzing the structural dynamic equation for floating wind turbines,and considering the effect influenced by wind and wave on the wind turbines,the operating strategies for reducing the pitching movement are given,and reducing the pitching movement for floating wind turbines has an important significance.(2)The structure load problem for floating wind turbines is researched.By using active control force from MR damper and adaptive control strategy,the load of floating wind turbines is reduced obviously.(3)The load problem of floating wind turbines from floating platform is studied.Considering the influence of mooring system,floating wind turbines load is analyzed by a multi-stage control method,which is based on the designed active controller.Under different sea conditions,two control methods are designed and applied to reduce the load occurred by platform.(4)The simulation analysis for reducing load of cabin and platform is made based on MATLAB/FAST simulation platform.Then the 5 MW barge floating wind turbine is used to verify the effectiveness of the methods proposed.In addition,the load of floating wind turbines is reduced ultimately.(5)The visibility for floating wind turbines is considered.Then the visual interface is designed to realize real-time monitoring function to observe the structural state of wind turbines.The software WinCC flexible smart v3 and the wind turbines datum from MATLAB/FAST are utilized to design the interface.