Papers

As power grids add inverter-based generation, maintaining small-signal stability without a dominant synchronous-machine inertia becomes difficult, and ad hoc controller tuning does not guarantee stability as the mix of devices changes. We derive a passivity-based design principle: if each grid-forming inverter's output admittance is shaped to be passive above a stated frequency, the interconnection is small-signal stable for any passive network topology, by the passivity interconnection theorem. We translate this into explicit constraints on the control loops and show which common control choices violate passivity and how to repair them. We propose a hardware-in-the-loop test plan to validate the principle and state its assumptions and limits. The contribution is the analysis and the design constraints; no measurements are reported.