Designs Of Offshore Floating Wind Turbine Vibration Systems Based On Passive Mechanical Networks And Model Predictive Control

In recent years,global energy shortages and environmental degradation have become increasingly prominent,attracting many countries to invest funds and energy in the development of renewable and clean energy projects.Among them,wind energy,as one of the most promising clean energy,has developed rapidly in recent years and occupied an important position in energy supply with the characteristics of low cost,mature technology and high reliability.However,due to the special working environment of offshore floating wind turbines,the interference of external factors will cause vibration of the wind turbine part,resulting in shortening the service life of the wind turbine,so it is of great significance to study the vibration damping control of offshore floating wind turbines for the development of deep-sea wind energy,that is,to improve the utilization rate of wind energy.Aiming at the problem of vibration caused by wind and wave disturbance of floating wind turbines,this thesis uses the network synthesis method and the model predictive control technology based on Kalman filter to design the vibration damping control of floating wind turbines,and verifies the applicability of the proposed method through high-fidelity wind turbine simulation experiments,including:(1)Dynamic modeling of offshore floating wind turbines.This thesis uses the principle of Lagrange second equation to establish a dynamic model of offshore floating wind turbine system,through which the functional relationship between the control input of the wind turbine system and the motion characteristics of the wind turbine is described,and the influence of the coupling characteristics generated by the interaction between wind and wave and the wind turbine structure in a complex aeroelastic and hydroelastic way on the system performance is considered.(2)The optimization design of passive vibration damping control system for offshore floating wind turbine based on network synthesis method was studied.The passive mechanical network including damper,spring and inertia is set in the vibration damping device of the wind turbine nacelle,and the optimal design of the offshore floating wind turbine damping system and its comprehensive realization when the network admittance is different types of positive real functions are studied.Firstly,the state space model of the damping control system of the wind turbine is established,in which the admittance function of the passive network is used as the transfer function of the controller,and then four performance indicators are defined according to the output of the wind turbine system,and the numerical optimization problems of single index and multi-index are established respectively,and the admittance controller is limited to several different types of positive and real functions,and the corresponding optimization results are obtained and compared by using the optimization toolbox in the simulation software.Finally,using the comprehensive conclusion of low-complexity network,the optimal positive real function physics obtained by optimization is realized as a damper-spring-inertial network,and the wind turbine high-fidelity simulation software is used for time domain simulation.Since more situations are considered in the optimization design process,the research method is more general than the fixed structure study.(3)The design of active vibration damping control system for offshore floating wind turbines based on Kalman filter and model predictive control method was studied.Based on the structure of the original classical tuned mass damper in the wind turbine nacelle,the feedback optimization control based on model predictive control is adopted,and the influence of wind and wave disturbance changes on the performance of the wind turbine during the working time of the wind turbine is improved in real time through online rolling optimization.Combining the Kalman filter and the model prediction controller,a composite model prediction controller is designed,which estimates and corrects the current state of the system considering the system noise and measurement noise.Finally,the wind turbine simulation software FAST verifies that the control method has a good effect on the improvement of the damping performance of the wind turbine.