Analytical Model of A Grid-Forming Inverter

Recently, inverter-based resources are being integrated into the power grid at a rapid rate. Most of these resources are grid-following inverters, where weak grid operation becomes an issue. The research focus has now shifted towards grid forming inverters, which emulate synchronous generators. Thus proper modeling and analysis are required to understand the grid forming inverters. This paper presents the nonlinear analytical model of a grid forming inverter when operating in grid-connected mode in $dq$ -domain. The developed model is validated in the time domain with the Electromagnetic Transients (EMT) test bed when the system operates under weak grid conditions. The analytical model is also used to perform the eigenvalues analysis. The EMT model is simulated in MATLAB/Simscape and the analytical model is simulated in MATLAB/Simulink. Hardware experimentation is also performed for further bench-marking with the help of laboratory scale hardware setup.