Stability Analysis of Grid-Following and Grid-Forming Converters Based on State-Space Model

This paper analyzes and compares the control loops of the grid-following and the grid-forming voltage source converters connected to the power grid. Eigenvalue trajectories are studied in order to obtain an accurate stability analysis. A time-domain simulation model of 15 kW grid-connected converter is built in Matlab/Simulink to discuss the stability of the grid-following control and the grid-forming control under the conditions of different short-circuit ratios. The stability boundaries of the grid-following control and the grid-forming control are obtained. The result reveals that the grid-following control is more suitable for the stiff power grid, while the grid-forming control is more suitable for the weak power grid.