A Comprehensive Review of Grid-Forming Control Studies Based on Virtual Synchronous Generators

With the proposal of the "dual carbon" target plan, the power grid is gradually showing a "dual high" characteristic dominated by "high proportion of new energy and high proportion of power electronic equipment". Generally speaking, new energy generation is connected to the AC micro-grid through inverter devices. However, due to the lack of inertia and damping of synchronous generators in inverter equipment, when it is heavily connected, it may lead to insufficient system inertia and damping. When the system is disturbed, the inverter's ability to suppress interference weakens, and may even lead to system frequency collapse. To address this issue, virtual synchronous generator control is introduced, which incorporates the rotational inertia and damping coefficient of the synchronous motor into the control of the inverter. This measure improves the frequency response characteristics of the system and enhances the anti-interference ability of the micro-grid. However, while VSG control improves system stability, it also sacrifices certain dynamic tuning performance. In order to further optimize performance on the basis of VSG control, so that the system can better adapt to various working conditions and external disturbances, and improve the overall flexibility and robustness of operation. In the paper, the basic principle of virtual synchronous generator was first discussed, and then the impact of virtual synchronous generator integration on low-frequency oscillation was analyzed in detail. Subsequently, the control strategies for the inertia and damping parameters of the virtual synchronous generator were discussed, and its key role in the control system was elaborated. Finally, further thoughts and prospects are proposed for the application of virtual synchronous generators in new power systems.