Viability assessment of matching control for grid-forming inverters in future low-inertia grids

This article investigates the operational viability of matching-controlled grid-forming inverters in power systems with varying grid strength. A combined small-signal and electromagnetic transient analysis is used to examine converter-grid stability mechanisms under representative disturbance scenarios consistent with IEEE Std. 2800–2022 requirements. Small-signal analysis based on a 17-state state-space model shows that matching control distributes swing dynamics between DC-link voltage and phase-angle states, providing an intrinsic energy-balancing mechanism as grid strength decreases. Representative tuning within the stable operating region corresponds to a nominal matching gain corresponding to the ratio of nominal frequency to nominal DC-link voltage, which lies within the well-damped stable operating region identified by the small-signal sweep, and voltage and current loop feedforward gains of 0.7 and 0.8, respectively. IEEE 9-bus simulations demonstrate that matching control stabilizes a severe 0.9 p.u. load-step event, whereas the baseline droop configuration reaches its stability limit despite auxiliary enhancements. Matching control limits DC-link voltage deviation to about 2% with a 0.15 s recovery time and no sustained oscillations. Additional validation in the IEEE 39-bus system with 80% renewable penetration confirms that the observed stability characteristics persist in larger networks. These results indicate an architecture-specific trade-off, as matching control extends the stability margin under severe energy-imbalance conditions where droop control approaches its stability limit, while producing larger and less-damped frequency excursions under moderate disturbances and large-scale fault conditions.