Enhanced AC Fault Ride-through Control for MMC-integrated System Based on Active PCC Voltage Drop

When a renewable energy station (RES) connects to the rectifier (RS) of modular multilevel converterbased high-voltage direct current (MMC-HVDC) system, voltage at point common coupling (PCC) is determined by RS control methods. For example, may become saturated under fault, and causes change from an equivalent source source, making fault analysis more complicated. In addition, grid code ride-through (FRT) requires RES output according its terminal voltage. This changes leads regulation redistribution, resulting in response interactions. To address these issues, this study describes how integrated system has five operation modes three characteristics duration fault. The also reveals several instances performance degradation such as AC loop saturation, shows that power reversal can be significantly improved. A novel FRT method proposed achieve controllable PCC continuous transmission actively reducing amplitude. robustness theoretically proven parameter variation mode switching. Finally, feasibility verified through MATLAB/Simulink results.