High-Frequency Resonance Suppression Based on Cross-Coupled Filter and Improved Passive Damper for MMC-HVDC System

In recent years, incidents of high-frequency resonance (HFR) have been reported in Modular Multilevel Converter-based high voltage direct current (MMC-HVDC) systems. These incidents are primarily attributed to the interaction between the impedance characteristics of MMC and AC system. Additionally, complex system operating conditions and poor stability margin have introduced new HFR risks, challenging the conventional suppression methods under changeable conditions. Therefore, this paper proposes an active and passive joint damping HFR suppression method, utilizing a novel cross-coupled filter (CCF) and the improved C-type filter damper. The impedance models of the MMC and AC system are provided to reveal the mechanism of HFR and analyze the suppression methods. Based on the detailed parameter tuning, the proposed method can effectively eliminate the risk of HFR and provide sufficient phase margin, ensuring stable and robust operation performance. The effectiveness of the proposed method is verified through simulations of the MMC-HVDC system.