Analysis of X/R Ratio Effect on Stability of Grid-Following and Grid-Forming Converters

The power system is undergoing significant changes with the increasing integration of renewable energy sources, such as wind and solar. The high penetration of these renewable energy sources has posed new challenges on the stability of the power grid. In response to these challenges, grid-following and grid-forming converters have been introduced as an effective solution for the modern power system. However, the impact of the X/R ratio in the power grid on the stability of these converters is not well understood. In order to fill in this gap, this paper conducts a detailed analysis on the control schemes of both the grid-following and grid-forming converters, and analyzes the eigenvalue trajectories with the change of the X/R ratio. To investigate how the X/R ratio affects the stability of the grid-following and grid-forming converters, a time-domain simulation model is built in Matlab/Simulink. The result reveals that the stability of both the grid-following converter and the grid-forming converter is improved when the X/R ratio is decreasing.