Nonlinear Fault Ride-Through of Grid Forming Converters with Power Synchronization Control

Grid-forming (GFM) converters, recognized as a key mechanism for providing frequency and voltage support to weak power grids, confront a significant challenge in maintaining stability during severe voltage dips and providing fault ride-through (FRT) capability. To tackle this challenge, this study first uncovers why GFM converters lose their synchronization during the current limit operation mode subjected to grid-side voltage dips. Then, a nonlinear analytical control law for power synchronization control (PSC) based GFM power converters to enhance their FRT capability during grid side severe voltage dips is provided.The effectiveness of the proposed methods is shown through time-domain EMT simulation results, and it is investigated for grids with different short circuit ratios (SCRs).