Research On Maximum Wind Energy Tracking Control Of Doubly Fed Wind Power System

Under the impetus of global fossil energy shortage,environmental pollution and other issues,the power converts to new energy power of green,low carbon,environmental protection.Wind power as an important type of new energy power plays an important role in the global economic and social development process.At present,domestic and foreign wind power market in the DFIG is still one of the main wind turbine types.The key point of the research on wind power systems' control is how to make the wind energy conversion system most efficient,and make the maximum power output largest.Thus,maximal wind power capture based on DFIG has important theoretical and practical significance.Firstly,the paper introduces the domestic and foreign present situation and development trend of wind power research,and then analyzes the doubly-fed wind power system in two important aspects-operation principle and characteristics of the wind turbine and double-fed induction generator.On the basis of theory,this thesis establishes mathematical models of aerodynamics,doubly fed induction generator under every coordinate and gearing.Secondly,this thesis studies the maximum wind energy tracking operation mechanism,which is an important basis for control.Additionally,this thesis comparatively analyzes various control algorithms for maximum wind energy tracking,so we know the results of the methods of optimization and disadvantages.In this thesis,based on the classical theory of PI,PI controller is designed,in order to verify the performance of the PI controller in Matlab / Simulink to build a model of each module doubly-fed wind power system and the PI controller.And whole system simulation the results verify its feasibility at the maximum wind energy tracking control,but at the same time reflects the control efficiency of the conventional PI controller undesirable problems.Finally,in-depth study of the basic principle of the sliding mode variable structure control,the proposed control method of maximum wind energy tracking based on sliding mode control for doubly-fed wind power system and the combination of the characteristic of doubly-fed wind power system.The control law and sliding surface is designed and build amodel of each module in the simulation software and the simulation.The simulation results of this method can be seen as compared with the conventional PI control,it is better able to stabilize the tip speed ratio so as to achieve the maximum,the highest wind energy utilization efficiency,and high accuracy than PI control,reflecting the rapid,good simulation results.It shows that this method can achieve maximum wind energy tracking control and excellent performance in all aspects.