Research On High Performance Control Of Offshore Hydraulic Wind Turbine Under The Influence Of Parameter Uncertainty

Offshore wind power generation adopts hydraulic transmission,which can reduce operation and maintenance costs and improve power quality.The offshore hydraulic wind turbine has the characteristics of large inertia,large load and strong wind load fluctuation.These characteristics will affect the control process related to grid-connected speed and maximum power point tracking(MPPT).This research discusses the influence of wind turbine external disturbance and internal parameter uncertainty on the grid-connection speed control and MPPT control.External disturbance refers to the transmission of offshore wind with fluctuating characteristics from high inertia wind turbines to hydraulic transmission systems,resulting in system pressure fluctuations and affecting the stability of control systems.There are two main reasons for parameter uncertainty: firstly,the impact of inaccurate controller parameter settings on the system.The second is the influence of the uncertainty of the specific value of the soft parameters of the hydraulic transmission system on the control system due to the influence of temperature,system pressure changes and component leakage during the system operation.This research presents a feedback linearization and radial basis function(RBF)neural network adaptive combined control method for the grid-connection speed control and MPPT control of offshore hydraulic wind turbines under internal and external disturbance conditions.The feedback linearization method is used to deal with the state space equation of offshore hydraulic wind turbine with affine nonlinear characteristics.Aiming at the problem that the hydraulic soft parameters of the transmission system are uncertain,RBF neural network is used to approximate the unknown term of the state space equation.And the weights and related parameters of the neural network are corrected on-line in real time by an adaptive method.The simulation results in Matlab/Simulink show that the combined control method of grid-connection speed and MPPT control based on feedback linearization and RBF neural network adaptive method proposed in this research can maintain good robustness under external wind disturbance and internal parameter uncertainty disturbance.And the combined control method can achieve the predetermined control objectives.The combined control method of grid-connection speed and MPPT control is verified through the semi-physical simulation experimental platform of 24 k W hydraulic wind turbine.The experimental results show that these control methods are effective and feasible.