Analysis and improvement of VSG dynamic frequency performance considering DC-side voltage stability

The Virtual Synchronous Generator (VSG) enhances the dynamic performance of voltage source converter (VSC) by emulating the characteristics of Synchronous Generators (SGs). When implemented within Multi-Terminal Direct Current (MTDC) systems, the VSG plays a critical role in the regulation of DC voltage. In such applications, it is imperative for the VSG to precisely follow the power references set by external DC voltage control loops. However, a trade-off is identified in current VSG implementations with fixed inertia control: a conflict between rapid reference tracking and high virtual inertia, resulting in a compromise between the transient response of active power and angular frequency. Furthermore, VSGs equipped with DC voltage cascade control exhibit a conflicting relationship between voltage droop coefficients and damping coefficients. Given these complexities, the impact of VSG control parameters on power, angular frequency, and DC-side voltage stability is analyzed in this paper. Subsequently, a comprehensive parameter adaptive method is proposed, encompassing inertia, damping, and droop parameters. The objective is to provide a swift power response and stable frequency support while maintaining a balance between power regulation and frequency regulation across diverse operational conditions.