Parameter design and adaptive adjustment strategy based on energy function method for enhancing the dynamics of grid-forming converters under large disturbance conditions

This paper presents a systematic parameter design approach for grid-forming converters (GFMCs) to enhance system dynamics under large disturbance. First, the power-synchronization loop of GFMC with dynamics similar to the swing equation is modelled, where the virtual inertia constant and damping coefficient govern the converter’s response. By employing an energy-function (Lyapunov) method, the sufficient conditions are derived to guarantee a new post-disturbance equilibrium and ensure that the kinetic energy dissipated surpasses the acceleration energy induced by a sag. These conditions yield explicit boundaries for the virtual inertia constant and damping coefficient, defining a feasible parameter region for stability. Subsequently, an adaptive parameter adjustment (APA) strategy is proposed to modify parameters in real time based on the measured frequency deviation, thus smoothing the response to voltage sags under large disturbance. Simulation studies are performed to demonstrate the effectiveness and validity of the proposed parameter design and APA strategy under the large disturbance conditions.