Inertial Control Applied to Synchronverters to Achieve Linear Swing Dynamics

Power system stability has become a critical aspect with increasing integration of converter-interfaced generators (CIGs). The power system is evolving from synchronous generators, with high inertia and slow nature, to CIGs, with little or no-inertia and very fast dynamics. The challenge lies in the smooth transition from reliable operation with synchronous machines to operating dynamic power-electronics based generators (up to 100%). The idea is to explore the flexibility offered by Power Electronics (PE) to develop control strategies such that a linear and uniform system dynamics (LSD) can be achieved. In this paper, inertia-control is proposed to achieve LSD. This linearizes the behavior of converters and hence enables stability analysis using simple tools for linear system. Following which, a novel control law based on delta-based linearized swing equation is proposed to achieve LSD. It transforms the control problem from regulation of power to regulation of power-angle. A new constant, namely rocof constant, is defined. The dynamics equations are presented with the stability analysis. Time-domain simulation results, using MATLAB, are presented for these control strategies for a Single Machine Infinite Bus (SMIB).