Frequency and Voltage Stability Analysis of Grid-Forming Virtual Synchronous Generator Attached to Weak Grid

Virtual synchronous generator (VSG) control technique is widely used for the grid-friendly integration of renewable energy. However, when VSG attached to a weak grid, it prone voltage and frequency instability, which aggravates quality at point common coupling, in turn, pollutes supplying loads. On one hand, focusing on stability, this article proposes impedance modeling synchronously inertial reference coordinates measure stability grid-tied identify interaction between power grid. Studies show that grid strength can lead wideband oscillation VSG. other motion equation has been put forward illustrate dynamic deviation frequency. The relationship synchronizing ability stiffness discussed. Besides, an inertia-damping-strengthened method improve stability. Finally, theoretical analysis compared with simulations experiments.