Research On Maximum Power Tracking Control Strategy Of Wind Power Generation System

At present,the world is facing a shortage of non-renewable resources,environmental pollution and other status quo,how to find and use renewable energy to alleviate the current problems is particularly important.Wind energy is a green,efficient and economical renewable energy source and brings huge environmental and economic benefits.Many countries and local governments have introduced measures to support the further growth of wind power technology.In recent years,as the standard of wind power technology continues to advance,the requirements for the robustness,efficiency and stability of wind power systems have become more demanding and the research into specific strategies has become more detailed and in-depth.Due to the random and time-varying nature of the wind energy signal,the wind power system has internal parameter uptake and uncertain external disturbances that make it difficult to achieve MPPT,Therefore,based on the analysis of the current status of MPPT control strategies for wind power generation systems at home and abroad,the following research work is carried out in this paper:At first,the architecture of the wind power system and the performance characteristics of the wind turbine are analyzed,and the description of the mathematical model of the direct-drive permanent magnet synchronous wind power system is presented.To facilitate the analysis and investigation of the control variables and the design of the system control strategy,a strongly coupled problem exists in the maths model of the generator,which is transformed by coordinates and vector control strategy to build a mathematical model in the dq-axis system of coordinates.Then,in order to improve the operational quality of MPPT in wind power systems,a fixed-time convergent disturbance observer(Fx TDO)is firstly proposed to address the problem of slow estimation of uncertainty disturbances in wind power systems,which can estimate and compensate in real time within a fixed period of time,reducing the impact of system parameter ingestion and external uncertainty,etc.The design of a double power integral variable sliding mode controller for the control of the rotational speed loop introduces an integral term in the sliding mode function and uses the second order sliding mode nature of the double power convergence law to greatly reduce the jitter in the sliding mode control system and accelerate the convergence speed of the system,improving the tracking accuracy of the system.Finally,aiming at the low steady-state accuracy of the existing control strategy of MPPT for wind power generation system,a nonlinear smoothing function is introduced into the disturbance observer based on the extended state,which can improve the response speed of the observer,reduce the observation error,estimate the disturbance quickly and accurately and compensate dynamically.Non-singular fast terminal sliding mode controller can make the speed tracking error of wind power system converge to the equilibrium point in a limited time.The tracking error is obviously reduced,the convergence speed is accelerated and there is no overshoot.