Aggregation of voltage-control dynamics for grid-forming inverter modelling

The analysis of grid-forming (GFM) voltage-source inverters (VSIs) depends on small-signal models derived from phasor representation; however, by neglecting the voltage-control dynamics of GFM VSIs, conventional small-signal models cannot accurately capture the system stability boundary, dominant oscillation modes, and power coupling behaviour. To address this limitation, this paper presents a novel voltage-control aggregation method alongside a small-signal model capable of accurately representing the dynamic behaviour of GFM VSIs. The effectiveness of the developed method in replicating the system's critical dynamics is confirmed by theoretical analysis and experimental results.