Stability Analysis of Single-Loop Voltage-Magnitude Controlled Grid-Forming VSCs with Virtual Resistor

This article elaborates the stability analysis of the grid-forming (GFM) voltage-source converters (VSCs) with the single-loop voltage-magnitude (SLVM) control and the virtual resistor. It is revealed that the virtual resistor can greatly change the stability region of the SLVM controlled VSCs, even it is mainly used to eliminate the synchronous resonance introduced by the power control. The mathematical model is then derived, from which the stability region can be analytically obtained. Simulations and experiments validate the theoretical analysis.