A Low Voltage Ride through Strategy with Load and Grid Support for Grid-Forming Converters

The growing penetration level of distributed generation (DG) requires power converters to be more grid-friendly. Driven by this demand, grid-forming converters have emerged as a promising solution for DG integration. Through proper control strategies, a grid-forming converter can emulate the synchronous generator and provide substantial frequency and voltage support to the grid. Although the normal operation of grid-forming converters has been well studied in the existing works, the converter controls under large disturbances such as fault conditions have not been fully addressed yet. To fill this gap, this paper explores the operation of grid-forming converters under 3-phase symmetrical voltage sags. Moreover, a low voltage ride through (LVRT) strategy is developed to regulate the frequency and voltage magnitude of grid-forming converters. With the strategy, the grid-forming converter can provide voltage support and avoid being overloaded during grid faults. Finally, simulation results are provided to verify the proposed LVRT strategy.