Equivalent Circuit Model of Grid-Forming Converters With Circular Current Limiter for Transient Stability Analysis

Abstract

This letter develops an equivalent circuit model of a grid-forming (GFM) converter with a circular current limiter and analyzes its transient stability. It is revealed that the inner control loop can be simplified as a voltage source behind an equivalent resistor. Based on the developed model, theoretical analysis and experimental tests demonstrate that the transient stability of a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$P-f$</tex-math></inline-formula> droop-controlled GFM converter with the circular current limiter can be assured whenever there exist stable equilibrium points.

Topics & Concepts