Load Analysis And Load Shedding Of Spar-type Floating Offshore Wind Turbine

In this thesis,the Spar-type Floating Offshore Wind Turbine(Spar-type FOWT)is taken as the research object.The kinematic coordinate system is established by analyzing the degree of freedom of the steel body,and the dynamic equation of each structural model of the Spar-type FOWT is established in the coordinate system.Considering the complex ocean conditions in deep sea,this thesis analyzes the wave and current loads,discusses the effects of current effect and wave-current interaction on the tower load and floating platform motion of FOWT,establishes Spar-type coupled aero-elasto-hydro-servo model,and carries out load analysis on the coupled wind turbine model under complex loads.Dual loads in deep sea area lead to FOWT tower load and floating platform movement.In this thesis,a multi-feedback control algorithm based on gain scheduling proportional integral(PI)pitch control and generator torque control is adopted,which not only effectively reduces tower load,but also slows down the floating platform movement.In summary,this thesis mainly discusses the load analysis and load-shedding control of the Spar-type FOWT.The work accomplished is as follows:(1)The load issue of the Spar-type FOWT is studied.The load response curves of wind turbines under three sea conditions: wave,wave and current without interaction,wave and current with interaction are analyzed.The load response curves of tower-base bending moment,tower-top displacement and platform pitch motion are analyzed.(2)A multi-feedback control algorithm based on gain scheduling PI pitch control and generator torque control is proposed,and the effectiveness of the algorithm is demonstrated.The single feedback control and multi-feedback control are compared.The simulation model and experimental data are built by MATLAB/FAST to verify the practicability and effectiveness of the proposed algorithm for load shedding of the Spar-type FOWT.