标题：Fundamental-Frequency Reactive Circulating Current Injection for Capacitor Voltage Balancing in Hybrid-MMC HVDC Systems During Riding Through PTG Faults

作者：路茂增; 胡家兵; Zeng, Rong; He, Zhiyuan

摘要：This paper presents a comprehensive analysis and a novel solution for the discharge problem on the half-bridge submodules’ (HBSMs’) capacitors in the hybrid modular multilevel converter (MMC)-based high-voltage direct current transmission systems under a long-term (e.g., several minutes or longer) poleto-groundfaultcondition.Themechanismofthisissueisanalyzed, and then a solution based on fundamental-frequency reactive circulating current (FFRCC) injection is proposed. The influence of FFRCCinjectionisanalyzedintermsofthefluctuatedarmcapacitorenergyandthecurrentstressofsemiconductors.Moreover,an enhanced arm voltage modulation method based on HBSMs and full-bridge submodules coordinate control is proposed to accelerate the capacitor voltage balance of HBSMs. Finally, the performanceoftheproposedcontrolstrategyisverifiedbythesimulation results.

发表于：IEEE TRANSACTIONS ON POWER DELIVERY

发表时间：JUN, 2018