具有直流故障阻断能力的混合型模块化多电平换流器

摘要

When reverse blocking MMC (RBSM-MMC) topology process fault current at DC side,huge overvoltage occurs in the lower tube reverse blocking IGBT.The block needs to meet very high pulse blocking consistence requirement in order to avoid components burning down due to huge overvoltage across IGBT.A hybrid model of RB and HB MMC (RB-HBSM-MMC) is proposed to resolve the problem of fault blocking capacity of traditional MMC and RBSM-MMC triggering consistence and spike voltage.Based on analysis of hybrid topology structure and fault blocking mechanism,a double-ends MMC-HVDC system is set up on PSCAD/EMTDC simulation platform.Simulation result shows that proposed RB-HBSM-MMC can effectively block DC-side fault current and isolate fault.Compared to RBSM-MMC,RB-HBSM-MMC can realize both effective blocking of DC-side fault current and transfer transient spike voltage to resolve overvoltage,reduce technical requirement for consistence of system triggering.It has good prospect of application.%逆阻型MMC(RBSM-MMC)拓扑在处理直流侧故障电流时,下管逆阻型IGBT模块会出现较大的过电压,需满足极高的脉冲闭锁一致性,否则IGBT两端会承受极大的过电压,烧毁器件.提出了一种半桥-逆阻混合型MMC(RB-HBSM-MMC)拓扑,用于解决传统MMC的故障阻断能力和逆阻型MMC触发一致与尖峰电压的问题.在分析其混合拓扑结构及其故障阻断机理基础之上,在PSCAD/EMTDC仿真平台搭建双端MMC-HVDC系统.仿真结果表明:所提出的RB-HBSM-MMC能有效阻断直流侧故障电流,隔离故障.RB-HBSM-MMC相比于RBSM-MMC,既可以实现对直流侧故障电流的有效阻断并能转移瞬时尖峰电压,解决过电压问题,降低对系统触发一致性技术要求,具有较好的应用前景.