Analysis on Difference of Dynamic Characteristics and Stability Between Synchronous Generator and Virtual Synchronous Generator

With the development of the power system, new energy generation equipment is gradually replacing traditional synchronous generators, and the regulation resources are becoming increasingly scarce. Using virtual synchronous generator (VSG) control technology to control the grid-connected converter of new energy generation equipment is an effective method to address this challenge. VSG simulates the rotor dynamics equation of the generator in the controller, so it is considered to be able to provide inertia and damping for the system. However, existing research results lack analysis of the differences between VSG and synchronous power generation, resulting in inaccurate evaluation of VSG stability and dynamic characteristics. This paper takes VSG based photovoltaic system connected to microgrids and distribution system as the research object, and analysis the differences between VSG and synchronous generators from several dimensions such as the characteristics of the prime mover, the implementation method of the rotor motion equation, and influence of the line impedance of the connected system. Theoretical analysis and simulation have shown that the above differences will lead to differences in stability and parameter security domain between VSG and synchronous generators.