Research On Converter Control Strategy Of Permanent Magnet Direct Drive Wind Turbine

Since the countries of the world entered the new century,the speed of economic development has been accelerating,and the accompanying impact is that resources and the environment have gradually become the two key issues for the survival and development of human society.Therefore,the demand for clean energy in the world is growing..The increasing demand in the market has made the development of technologies that use clean energy become the development direction of all countries in the world,and various clean energy technologies are developing rapidly.Among various clean energy sources,wind energy has been widely exploited and utilized in countries all over the world because of its rich content and wide range of distribution,which can effectively alleviate environmental pollution problems.Wind power technology is becoming more mature as the design dimensions and power levels of commercial wind turbines increase rapidly.In the development of wind power technology,the development of constant-speed constantfrequency power generation technology to variable-speed constant-frequency power generation technology has gradually evolved.The development of wind power generators has also entered a period of rapid development.The permanent magnet direct-drive synchronous generator has become a key research and development object.The breakthrough has been achieved.The synchronous generator has been widely used in wind power generation due to its simple structure,good stability,small size and light weight.In order to make the conversion efficiency of wind energy efficient and stable.In this paper,the permanent magnet direct-drive wind turbine is taken as the research object,and the wind turbine generator system side is analyzed and researched.The maximum wind energy capture of the wind energy system is realized,and the corresponding control strategy is given to improve the conversion efficiency.The analysis and research make it realize the stability of the DC bus voltage,and adopt the corresponding control strategy to realize the unit power factor grid connection,which improves the wind power conversion efficiency.Firstly,the research background and current situation of the wind turbine simulation system are analyzed and studied,and the overall structure of the wind turbine and the structure of the converter are determined.According to the change of actual wind speed,four combined wind speed models which can accurately reflect the abruptness,gradual change and randomness of actual wind speed are built.Then the control principle of the permanent magnet direct drive synchronous generator is analyzed and studied.The mathematical modeling and the control principle of the machine side and grid side converter for the dual PWM converter control system based on permanent magnet direct drive synchronous wind power generation are studied.Mathematical modeling.In this paper,the optimal power tracking is obtained based on the optimal tip speed ratio.The vector-side control is adopted for the machine-side converter,and the grid voltage vector is controlled for the grid-side converter to achieve the active and reactive power.Decoupling,the controller selects the PI controller to enable the system to finally realize the unit power factor generation of the wind power system.Finally,the corresponding system simulation model was built under Matlab / Simulink simulation software and simulated on the software.Through the observation of the simulation results,it is verified that the control strategy can achieve the maximum power tracking of the wind and can stabilize the DC bus voltage well.The unit power factor generation is connected to the grid,which verifies the feasibility of the control strategy.