Analysis of LVRT control strategies for grid-tied photovoltaic system under symmetrical faults and grid fluctuation conditions

Abstract Photovoltaic (PV) microgrid systems have emerged as key gears in sustainable decentralizing energy production. However, grid voltage fluctuations and line faults pose a significant concern in PV microgrid integration leads to voltage deviations, affecting the quality and reliability of power supply to end-users. An advanced inverter control strategy, based on Proportional-Resonant (PR) controller is presented in this paper for handling this issue. The test model is designed with a P-Q based low-voltage-right-through (LVRT) control capability. This model is tested under a balanced fault state and an intentional grid voltage fluctuation condition. The PV model with proposed current control strategies (LVRT+PR) offer more effective means to regulate voltage levels within predefined limits. Comparing with conventional proportional-integral (PI) controller, this control strategy is found to be dynamically better in adjusting the output waveforms at point of common coupling (PCC) and stabilizing grid voltage, thereby enhancing system reliability and grid compatibility.