Optimization Of Control Strategy Based On Wind Turbine Operation Status

Wind energy plays an extremely important role in the process of global energy transformation to clean and sustainable energy.In recent decades,the capacity of single wind turbine and the geometric size of blades have been increasing,which not only improves the power generation and energy efficiency,but also brings challenges to the operation and maintenance of wind turbines.In particular,the influence of wind shear and tower shadow effect on key bearing components of wind turbines is intensified.Therefore,the optimization control method for load reduction and vibration reduction of wind turbines is studied,and the problems such as power maximization,load reduction,service life extension and operation reliability are comprehensively considered in the process of controller design,which has attracted wide attention in the field of wind power.The main contents of this paper are as follows:(1)The open source software OpenFAST for wind turbine modeling and load calculation and the relevant basic theories such as blade element momentum are introduced,and the blade flapping vibration model,tower fore-atf vibration model and drivetrain model of NREL 5MW wind turbine are established.(2)The basic operation control strategy of variable speed variable pitch wind turbine is analyzed,and the application of disturbance accommodating control method based on state observer in multi-objective independent pitch control of wind turbine is introduced,and its insufficient robustness in model error and unmodeled dynamics is analyzed.A Stochastic disturbance accommodating control method combined with Kalman filter is proposed to reduce the influence of nonlinear and unmodeled dynamics,which can further suppress the vibration of blades and towers.(3)The Paris model of blade crack growth was established.The load data provided by OpenFAST was used to calculate the length of crack growth.The uncertainty of operating conditions was described based on Rayleigh distribution.At the same time,combined with the life distribution given by the prediction,the blade life integrated control strategy was designed to coordinate the load mitigation capacity and the work load of the variable blade system.The feasibility of the blade life integrated control strategy was verified by simulation.(4)The risk-based maintenance decision framework of component is analyzed,the generalized expected maintenance cost model and blade life cycle model are established,and the corrective maintenance strategy and preventive maintenance strategy are analyzed.The research shows that the above operation and maintenance strategy may lead to the failure of the wind turbine outside the inspection and maintenance period,and the preventive maintenance time point of each blade is not uniform.Increase maintenance costs.To solve this problem,a periodic maintenance plan combining blade life prediction and integrated life control strategy is proposed to make each blade perform preventive maintenance at the same time node,so as to reduce operation and maintenance costs and improve economic benefits.