Lead-Lag Filter-Based Damping of Virtual Synchronous Machines

Abstract

Traditional power systems based on synchronous generators often feature low frequency electromechanical oscillations. However, the integration of renewable energy sources through power converters can help tackling this issue. In fact, thanks to the concept of virtual synchronous machine (VSM), it is possible to make the inverters behave as real synchronous machines (SMs). This way, the inverters can be integrated into the grid as traditional SMs and can even outperform them when it comes to damping low frequency oscillations in the power system. To do that, proper damping algorithms must be adopted in the VSM model. Therefore, this article presents a simple and straightforward damping method for VSMs based on a single lead-lag filter acting on the VSM active power feedback. The proposed method and its integration in the VSM model are described. Moreover, a comparison method and four performance indices are proposed, to better evaluate the performance of the VSM damping methods. Finally, the proposed solution has been experimentally compared to five conventional methods to highlight its features according to the proposed performance indices.