Robust Stability Analysis of Grid-Forming Converters Dominated Grids Using Grey-Box Modeling Approach

In the recent years, a continuous effort have been made for modeling and stability analysis of converter dominated grids. Ensuring stability in converter dominated grid presents a unique challenge, primarily due to manufacturers’ intellectual property (IP) protections. Determining the robust stability boundary of a grid incorporating converters from various manufacturers remains an area requiring extensive research. Recently, a grey-box modeling approach for studying interoperability has been proposed in literature. However, the existing methodology is solely suitable for grid following converters. This study bridges the gap by proposing GFM converters model which aligns with the methodology for analyzing interoperability of GFL converters. The model is designed to represent a range of control system implementations across different manufacturers. Using robust control theory, this approach assesses the grid’s stability margin and sensitivity analysis of the uncertain control loops under various conditions considering a single GFM converter. The results are validated both analytically and through real time hardware-in-the-loop (HIL) test to demonstrate the model’s accuracy in predicting robust stability margin and the sensitive of the control loops in GFM converters dominated grids.