Research On Optimal Control Method Of Doubly-fed Wind Turbine Power Converter

In this era of rapid development in all aspects,phenomena such as environmental pollution and energy shortage are intensifying.As the green and renewable energy source,wind energy is very important for in-depth and efficient use of research.In this regard,all countries in the world have vigorously developed with a high degree of attention,and are constantly innovating in technology.Nowadays,wind power technology is developing rapidly,and the installed capacity is growing rapidly.The research content of wind power technology focuses on maximizing the use of wind energy to further improve the operating efficiency of the power generation system.The form of doubly-fed wind power has gradually occupied the mainstream of the market Because of its own small excitation capacity,fast dynamic response speed,smooth grid connection and outstanding economy,it has been widely used.The dual PWM converter has the advantages of adjustable and high power factor,less harmonic content,and excellent transmission performance during operation,and has been used as the excitation power source of the motor many times.This paper takes doubly-fed wind turbines as the object,based on the Matlab / Simulink software platform,and carries out the following research work on the optimization control method of its power converter:First,the development and basic composition of the doubly-fed power generation system are introduced.The variable-speed constant-frequency working principle of the power generation system and the several working states of the doubly-fed motor changing with wind speed are briefly analyzed.The control method of the double PWM converter is described.Secondly,research on grid-side converter and rotor-side converter separately.For the grid-side converter,the PWM rectifier is applied to this,its topology and working principle are accurately analyzed,and a mathematical model is established.Based on the comparative analysis of the two methods of voltage-oriented control and direct power control,the direct-side power control method is used to construct a grid-side control system,and the stability of the DC-side output voltage under unit power output is verified by simulation.Based on the theory of electromechanics,the vector model of the doubly-fed wind turbine was established,and the rotor field-oriented vector control technology was used toconstruct a rotor-side converter system with active and reactive power decoupling control to achieve the maximum coefficient of wind energy utilization.Finally,a comprehensive simulation experiment is performed on the integrated power converter that integrates the two subsystems of the grid side and the rotor side.The results show that the control strategy adopted is feasible,the voltage regulation of the DC link is stable,the output power factor is high,the wind energy utilization efficiency is good and other features.