Research On Stability And Control Technology Of Microgrid Inverter Based On Virtual Synchronous Generator

With the large-scale integration of distributed power sources in the microgrid,the proportion of synchronous machines in the power grid continues to decrease,and the system moment of inertia is relatively reduced,causing the power grid to face increasingly severe stability challenges.In order to increase the moment of inertia of the microgrid and alleviate the stability problems caused by a large number of distributed power sources connected to the grid,the virtual synchronous generator control technology came into being.Using this control technology to control the inverter,the distributed power supply can simulate the operation external characteristics,inertia and damping characteristics of the synchronous generator,which can also participate in frequency and voltage regulation,and improve system operation stability.Based on the virtual synchronous generator control technology of the grid-connected inverter,this thesis analyzes the influence of its control parameters on the output power-frequency response of the distributed power supply,studies the adaptive control technology of the virtual synchronous generator parameters,and analyzes the stability of the microgrid based on the energy function.Detailed research contents are described as follows:First,the control technologies of common microgrid inverters are researched.The application and practice of virtual synchronous generator control technology has been introduced.Then,the circuit topology and grid connection model of the microgrid are studied,the mathematical model of the virtual synchronous generator of the microgrid inverter is established,and the control module of the virtual synchronous generator is designed.Next,a virtual synchronous generator parameter adaptive control strategy is improved,which can improve the stability of the microgrid by continuously and adaptively changing the virtual inertia and damping coefficient according to the real-time operating status of the microgrid.And its superiority in improving power frequency response has been verified.Last,the energy function of the microgrid when the virtual synchronous generator controls the microgrid inverter is deduced.Based on the energy function,the parameter adaptive control technology of the virtual synchronous generator is studied to be more intuitive and quantitatively evaluated the microgrid stability improved effectiveness of the introduction of the virtual synchronous generator.