中文摘要：

由于直流断路器成本较为昂贵，尚处于试验阶段，具备直流故障电流阻断能力的MMC拓扑才是实现输配电网可控性，提高MMC运行可靠性的关键。在分析了传统半桥型模块化多电平换流器（halfbridgeSUhnodulebasedmodularmultilevelconverter，HBSM—MMC）直流故障电流路径的基础上，对具有直流故障电流阻断能力的MMC子模块拓扑结构进行综述。分析了桥式子模块和箝位型子模块拓扑的直流故障电流阻断原理和故障时的电流路径，并对各种子模块拓扑的性能特点进行对比分析、归纳总结，为业内学者开展相关研究提供参考。

英文摘要：

Because of the high cost of the DC circuit breaker, and immaturity of its technology, the MMC topology with the DC fault current blocking ability becomes the key to realize the controllability of power grid and improve the operation reliability of MMC. Based on an analysis of the DC fault current path of the traditional half bridge modular multilevel converter （HBSM-MMC）, this paper reviews the topology of the MMC sub-module with DC fault current blocking capability. The DC fault current blocking principle and the current path during the fault are analyzed, and the performance characteristics of each sub-module topology are analyzed and summarized, which can provide reference for the scholars to carry out relevant researches.