Research On Active Disturbance Rejection Control For Pitch Control Of Offshore Floating Wind Turbine

During the operation of offshore floating wind turbines,the combined excitation of random wind and wave loads will cause the tilt motion of the platform and tower,which will significantly change the spatial operation attitude of the whole unit,and then change the relative inflow wind speed at different radial positions of the blade under different pitch angles,increase the fluctuation of power generation,and affect the service life of wind turbines.Pitch control system is an important part of offshore floating wind turbine,and the study of pitch control strategy is of great significance to maintain the stability of output power and prolong the service life of wind turbine.Taking the offshore floating wind turbine as the research object,the variable pitch control strategy is studied to maintain the stability of the output power of the wind turbine and suppress the motion of the platform.The main research work is as follows:(1)According to the operation principle of offshore floating wind turbine,the coupled dynamic model of wind turbine is established based on the sub-dynamic model of aerodynamic force,hydrodynamic force,structural system and variable pitch control system of wind turbine.Aiming at the problem of output power fluctuation of wind turbine under the combined action of wind and wave,a unified pitch active disturbance rejection control strategy is proposed,and a unified pitch active disturbance rejection controller is designed with constant torque control as the goal.(2)The bandwidth tuning method and BP neural network tuning method for tuning the parameters of the unified variable pitch ADRC are proposed to complete the tuning of the parameters of the variable pitch ADRC.The simulation model of offshore floating wind turbine is established based on FAST / Simulink software platform.The dynamic characteristics of offshore floating wind turbine under different wind conditions and combined action of wind and wave are studied respectively.The effects of unified variable pitch ADRC and PID control on pitch angle,power generation,generator speed,aerodynamic torque and platform motion are compared and analyzed.(3)In order to achieve the goal of maintaining power stability and suppressing platform motion at the same time,an independent pitch active disturbance rejection control strategy is proposed.Taking the wind wheel speed,platform surge displacement and rolling angle as the controller input,an independent pitch active disturbance rejection controller is designed.The effects of independent pitch active disturbance rejection controller and unified pitch active disturbance rejection controller on the power generation,generator speed and platform motion of wind turbines under different wind conditions and wind waves are simulated and analyzed.(4)Verification of Active Disturbance Rejection Control Strategy with Variable Pitch by GH Bladed Software The influence of the variable pitch active disturbance rejection control system under 3D turbulent wind on the pitch angle,power generation,generator speed and generator torque of the wind turbine is analyzed,and the effectiveness of the proposed variable pitch active disturbance rejection control strategy is verified.In summary,this paper studies the variable pitch control strategy of offshore floating wind turbines,designs the variable pitch active disturbance rejection controller according to the structural characteristics of wind turbines,and simulates and analyzes the performance characteristics of the variable pitch system and the suppression effect of platform motion,which provides a theoretical basis for improving the output power stability of wind turbines and extending the service life of wind turbines.