A New Modular Multilevel Converter Topology with Capability of DC Faults Clearing under Blocking and Non-Blocking Mode
Shu Hongchun1, Shao Zongxue1, Jiang Yaoxi2, Bao Guangjiao1, Wang Wentao1
1. Faculty of Electric Power Engineering Kunming University of Science and Technology Kunming 650051 China; 2. Faculty of Information Engineering and Automation Kunming University of Science and Technology Kunming 650051 China
Abstract：The existing DC short-circuit fault current clearing methods have the contradiction between clearing rate and economy. A five-level clamp crossed sub-module (FLCCSM) modular multilevel converter (MMC) topology is proposed, which can achieve rapid clearing of DC fault current at low cost in both blocking and non-blocking modes. The DC fault ride-through processes in the blocking and non-blocking clearing modes are analyzed; the configuration numbers of the capacitors of the sub-modules in the fault current path that meets the fault ride-through conditions in the two clearing modes are deduced; the balanced control of the capacitor inserting in group strategies to improve its voltage equalization effect is proposed. Matlab/Simulink simulation results show that FLCCSM-MMC can quickly clear the DC fault current to zero in the blocking mode, it is mainly used to deal with DC permanent faults. In the non-blocking mode, FLCCSM-MMC can quickly limit the arm current to less than 2 times of the rated value of the bridge arm current, and MMC still has the ability to transmit a certain amount of power, which is more suitable for dealing with DC transient faults, furthermore the capacitors voltages remain balanced before and after the fault. FLCCSM-MMC has the advantages of fast fault current clearing, high reliability, low device cost, and low operating loss.
束洪春, 邵宗学, 江耀曦, 包广皎, 王文韬. 具备闭锁和非闭锁模式抑制直流故障电流的新型模块化多电平变换器拓扑[J]. 电工技术学报, 2022, 37(21): 5526-5540.
Shu Hongchun, Shao Zongxue, Jiang Yaoxi, Bao Guangjiao, Wang Wentao. A New Modular Multilevel Converter Topology with Capability of DC Faults Clearing under Blocking and Non-Blocking Mode. Transactions of China Electrotechnical Society, 2022, 37(21): 5526-5540.
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2022, Vol. 37 
