具有直流故障自清除能力的新型MMC子模块及其混合拓扑

A new MMC sub-module with DC fault self-clearing ability and its hybrid topology

针对传统半桥型模块化多电平换流器(Modular Multilevel Converters,MMC)在高压大功率领域不能通过换流器自身控制来实现直流故障的阻断问题,提出一种新型的类半桥型(Similarity Half Bridge Sub-Module,SHBSM)子模块拓扑结构。直流侧发生极间短路故障时,需同时闭锁所有IGBT脉冲信号。为降低IGBT触发一致技术要求,进一步提出一种类半桥-半桥混合型子模块,无需所有IGBT同时闭锁。在PSCAD/EMTDC仿真平台搭建双端MMC-HVDC系统,仿真结果表明,所提出的类半桥型子模块,类半桥-半桥混合型子模块MMC能有效阻断直流侧故障电流,隔离故障。相比于传统半桥型子模块MMC,类半桥型子模块MMC以及半桥-半桥混合型子模块MMC均无需增加IGBT的投入,即可以实现对直流侧故障电流的有效阻断,因此,具有较好的应用前景。

Aiming at the problem that the traditional half-bridge Modular Multi-level Converters （MMC） cannot be controlled by the inverter itself to achieve DC fault blocking in the field of high-voltage power, a new Similarity Half Bridge Sub-Module （SHBSM） topology is proposed. It is need to block the entire IGBT pulse signal when the interpolar short-circuit fault occurs in the DC side. In order to reduce the technical requirements for IGBT simultaneously trigger, a mixed sub-module with SHBSM and Half Bridge Sub-Module （HBSM） is proposed without all IGBT blocking at the same time. The dual-ended MMC-HVDC system is built on the PSCAD/EMTDC simulation platform, the results show that the SHBSM-MMC and SHBSM-HBSM-MMC can effectively block the DC-side fault current and isolate the malfunction. Compared to the traditional HBSM-MMC, the SHBSM-MMC and SHBSM-HBSM-MMC don＇t need to increase the investment of IGBT and it is possible to realize the effective blocking of the DC side fault current, therefore, the SHBSM-MMC and SHBSM-HBSM-MMC have good application prospects. This work is supported by National Natural Science Foundation of China （No. 51667013）.