Independent Pitch Control Method Of Floating Offshore Wind Turbine Based On BP Neural Network Optimizing PID Parameters

With the aim of achieving carbon neutral in 2060 in China,offshore wind power has been developing rapidly in recent years.In 2020,China has become the largest offshore wind power market in the world for the third consecutive year.Offshore wind power construction is gradually moving towards deeper and farther away from coastline,and the research and development of floating offshore wind turbine technology is imperative.The control system of the offshore floating wind turbine is mainly modeled on the onshore fixed wind turbine,but the working environment of the offshore floating wind turbine is special,which will be affected by various load coupling effects such as aerodynamic load,hydrodynamic load and mooring load,as well as aerodynamic characteristics such as wind shear effect,tower shadow effect and wake effect.In order to reduce the unbalanced load of wind turbine and ensure the stability of output power,Now it is necessary to study more advanced control methods.With the development of Artificial Intelligence technology,it has become a trend to integrate intelligent algorithms into various research fields to obtain better optimization results.The pitch control method of floating offshore wind turbine based on artificial intelligence technology has also become a research hotspot in recent years.In this paper,the intelligent pitch control method of floating offshore wind turbine coupling model is studied and discussed in detail.The main research work is as follows:(1)The calculation method of environmental load of floating offshore wind turbine is introduced.The blade element momentum theory and generalized dynamic wake model are used to calculate the aerodynamic load of the wind turbine,and the wake model is modified in combination with the aerodynamic characteristics of the wind turbine;The linear wave theory,potential flow theory,Morison equation and time-frequency conversion method are used to calculate the hydrodynamic load in time domain;The quasi-static catenary equation is used to calculate the mooring load.(2)The pitch control process in the offshore floating wind turbine control system is deduced,the pitch control system model is built by Matlab/Simulink,and the coupling calculation model of offshore floating wind turbine is established by Kane equation.The basic module composition and function of the simulation tool OpenFAST software used in this paper and the basic parameters of OC3 Hywind wind wind turbine is introduced.Then the controller model is integrated into OpenFAST in Matlab/Simulink and joint simulation is carried out to verify the feasibility of the built control system model.(3)A PID independent pitch controller based on BP neural network optimization is designed,and the BP-PID controller is used in the independent pitch blade root load control loop.Aiming at stabilizing the output power of offshore floating wind turbine and reducing blade root load,this paper designs the independent pitch control strategy of offshore floating wind turbine by combining the power control unit of wind turbine adjusting pitch angle based on generator speed signal with BP-PID independent pitch control unit based on blade root load signal.The simulation results show that the independent pitch control strategy based on artificial intelligence technology proposed in this paper plays a significant role in reducing the blade root load of offshore floating wind turbine,maintaining the stability of output power,restraining the surge and pitch of floating foundation,and the overall performance of the wind turbine can be guaranteed,which verifies the effectiveness of this method.