并联全桥子模块MMC直流故障抑制性能仿真分析

基于并联全桥子模块(Paralleled Full-bridge Sub-modules，P-FBSM)的模块化多电平换流器(Modular Multilevel Converter，MMC)因具备良好的自均压能力和电流通流能力在高电平应用领域得到重视。目前针对P-FBSM-MMC的研究侧重于其自均压特性，而对直流故障阻断机理分析较少。文章为研究P-FBSM-MMC系统在发生直流侧双极短路情况下的故障电流抑制能力和恢复能力，首先分析P-FBSM-MMC在发生直流侧双极短路故障时的故障电流通路，然后利用PSCAD/EMTDC仿真软件搭建21电平P-FBSM-MMC和半桥子模块(Half-bridge Sub-modules，HBSM)MMC仿真模型，分析了P-FBSM-MMC在直流侧双极短路故障情况下的故障电流、直流侧电压以及故障恢复能力。通过与HBSM-MMC仿真结果对比验证得出结论：P-FBSM-MMC在发生直流侧双极短路故障情况下通过闭锁所有IGBT能够有效抑制故障电流，且直流电压能在解锁IGBT后的较短时间内恢复到额定值，对未来P-FBSM-MMC的研究有较大参考价值。

DC fault suppression performance and simulation analysis of Parallel Full-bridge Sub-module MMC

Modular Multilevel Converter (MMC) based on Paralleled Full-bridge Sub-modules (P-FBSM) obtained attention in high-level applications due to its good self-voltage equalization capability and good current passing capability. At present, the research on P-FBSM-MMC focuses on its self-voltage equalization characteristics, while there is less analysis of DC fault blocking mechanism. In order to study the fault current suppression capability and recovery capability of the P-FBSM-MMC system in the case of DC-side bipolar short-circuit, the fault current path of the P-FBSM-MMC in the event of a DC-side bipolar short-circuit fault is first analyzed. Then, the 21-level P-FBSM-MMC and Half-bridge Sub-modules(HBSM)-MMC simulation model was built on PSCAD/EMTDC simulation software, the fault current, DC side voltage and fault recovery capability of P-FBSM-MMC under DC-side bipolar short-circuit fault were analyzed. The conclusion was verified by comparison with the HBSM-MMC simulation results: the P-FBSM-MMC can effectively suppress the fault current by blocking all IGBTs in the event of a DC-side bipolar short-circuit fault, and the DC voltage can be restored to the rated value within a short time after the IGBT is unblocked, which has great reference value for the future research of P-FBSM-MMC.