| In recent years,the phenomenon of environmental pollution caused by the excessive use of fossil energy has become more and more intense,so new energy has become the focus of human attention.Wind energy is an important representative of new energy.It is favored by all countries because of its wide distribution and rich storage.At present,the use of wind energy is mainly reflected in wind power generation.With the maturity of wind power tower construction technology,wind power generation has become an important component structure of the modern power grid.The application of squirrel cage asynchronous generator in variable speed constant frequency wind power system only requires a converter with a small capacity and low cost.Therefore,the application of squirrel cage asynchronous generators in wind farms is still promising.In order to improve the power generation efficiency and quality of squirrel cage asynchronous wind turbine in the VSCF wind power system,the research contents of this paper are carried out from the maximum power tracking control technology and grid side converter control technology respectively.Firstly,this paper briefly analyzes the working process and energy conversion of squirrel cage asynchronous wind turbine,and defines the research goal of this paper;The common methods of maximum power tracking and grid side converter are compared and analyzed to determine the technical route adopted in this paper.According to the structure diagram of the squirrel cage wind power system,the important links involved in the technical route are mathematically modeled,laying the foundation for the control technology research below.Secondly,the principle of maximum power tracking is analyzed,and the rotor fluxoriented control technology is studied.Aiming at the complex control process and the problem that the control accuracy is affected by motor loss,the control method combining SVPWM technology and direct torque control is adopted.This control method only needs the generator stator resistance parameters and eliminates the current loop structure,improving system accuracy and response speed.Then,the grid side studies and analyzes the grid voltage-oriented control technology which is most widely used in engineering,and gives the control model.In view of the problems that a large number of approximate values affect the control accuracy in the PI parameter setting link and the poor voltage stabilizing ability in the case of serious disturbance,the sliding mode internal model control is introduced to improve the design of the controller to improve the control accuracy and stability of the system.Finally,the simulation models of maximum power tracking control technology and grid side converter control technology are built-in Simulink,and the simulation results are analyzed to verify the advantages of maximum power tracking control and converter control technology. |
