Challenges And Issues In LVRT Control Strategies For Grid-Interfaced PV Systems: A Brief Review

The increasing integration of grid-tied photovoltaic (GTPV) systems necessitates frequent updates to grid codes by grid managers to ensure these systems support the safety of the grid. A critical aspect of this is the low-voltage ride-through (LVRT) capability of PV inverters, which allows them to stay connected during short-term grid voltage disturbances. To comply with grid codes, PV inverters incorporate control strategies that ensure smooth operation during LVRT events. However, challenges such as phase voltage imbalance at the point of common coupling (PCC), current distortion, overvoltage in healthy phases, oscillations in active/reactive power and DC-link voltage, inverter overcurrent, and poor dynamic response have been identified during reactive power injection under LVRT conditions. This research examines current issues and strategies related to LVRT in GTPV inverters. It also discusses the limitations of traditional current control strategies and voltage support strategies and categorizes advanced LVRT control approaches based on grid-inverter synchronization methods, current reference generation techniques, and DC-link voltage control under various grid faults.