A Low Voltage Ride-Through Strategy for Gridforming Converters with Reactive Power Loop-Based Control

Grid-Forming (GFM) converters with reactive power loop-based (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$Q$</tex>-based) control show better performance in control structure, robustness and reactive power regulation compared to the voltage/current double-loop-based (VI-based) control. However, existing low voltage ride-through (LVRT) strategies are specially designed for VI-based GFM converters, and no dedicated approach for <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$Q$</tex>-based control. Additionally, most of these strategies fail to meet current LVRT standard. In this paper an LVRT strategy for <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$Q$</tex>-based GFM converters is proposed by utilizing its inherent reactive power loop and adjusting the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$Q$</tex> reference according to the LVRT standard. The strategy ensures reactive power support at the point of common coupling (PCC) while preserving GFM characteristics. Compared with conventional methods, the proposed strategy exhibits superior reactive power dynamic response and control accuracy, enables current sharing among multiple converters, and reduces power deviations. Effectiveness of the proposed LVRT strategy is verified by simulations in MATLAB/Simulink.