An Improved Predictive Control Strategy for Grid-Following Inverters During Voltage Sag

As power systems transition towards a more sustainable future with increasing integration of renewable energy sources (RES), the ability to handle low-voltage ride-through (LVRT) becomes essential for maintaining grid stability. This work investigates the impact of LVRT functionality for parallel inverter-based resources (IBRs) and explores the potential benefits of incorporating these IBRs to support the grid during voltage sags and contingencies. The study introduces a current reference generation method based on positive- and negative-sequence components to eliminate double-line frequency harmonics for grid-following (GFL) IBRs with LVRT capability. This approach enhances IBR performance under various grid disturbances by ensuring effective current limitation and accurate active and reactive power injection. The proposed method is implemented using Matlab Simulink under different unbalanced grid conditions to demonstrate the effectiveness of the approach in providing reactive power support according to grid code requirements.