Research On Structure Load Mitigation And Pitch System Fault-tolerant Control Of Offshore Floating Wind Turbine

In recent years,offshore wind power has developed rapidly as a sustainable and low-cost energy.To reduce the cost of offshore wind power,offshore wind turbines are developing in the direction of scale and large-scale.Deep-sea floating high-power wind turbines have become a research hotspot.However,under complex load conditions,the development of the floating wind power industry is constrained by the stability and reliability of wind turbines.Under the coupling effect of wind-wave external loads,the floating wind turbines endure significant loads and displacements.Therefore,it is of great significance to develop load mitigation techniques to reduce loads and guarantee the stability of floating wind turbines.At the same time,due to the complex and harsh operating environment of floating offshore wind turbines,once the pitch system fails,it is difficult for repairment in time.Therefore,the design of advanced fault-tolerant control strategies for floating wind turbine pitch systems is of great significance from the prospects of theory and practical application.In view of this,this paper takes the stability and reliability of floating offshore wind turbines as the research objective,and performs load mitigation control and pitch system fault-tolerant control for barge floating wind turbines.The main research content completed is described as follows:(1)Based on the Euler-Lagrange equations,a dynamic model of the barge floating wind turbine with a single active stroke limited tuned mass damper and multiple active stroke limited tuned mass dampers under complex wind-wave loads are established.An identification process of unknown wind turbine structural parameters is carried the effectiveness of the model is verified.(2)Two different active structure controller are carried for the barge floating wind turbine with a single active stroke limited tuned mass damper and multiple active stroke limited tuned mass dampers.The simplex coding genetic algorithm is used to optimize the elastic coefficient and damping coefficient of the damper to improve the load mitigation effect.The effectiveness of different tuned mass dampers and different is verified with the FAST and Simulink platform.Finally,the active structure control strategy based on multiple dampers in the highest load mitigation performance.(3)An nonlinear pitch system model under pitch actuator faults and unknown disturbance is established,and a state feedback(pitch angle and angular velocity)based adaptive fault-tolerant controller is proposed to guarantee that the pitch system quickly and accurately adjust the pitch angle to the desired angle.By introducing an adjustable convergence time function and a core characteristic function describing the uncertainty of the system,a fast and accurate tracking process of the desired pitch angle is guaranteed,which ensures the reliability and stable power output of the wind turbine system under load conditions.Finally,the effectiveness is verified by the FAST simulation platform.