| 引用本文: | 刘其辉,许倩倩,冯驰,田鑫,袁振华.一种用于海上风电全直流并网系统故障阻断的新型MMC子模块[J].电力自动化设备,2025,45(12):201-208. |
| LIU Qihui,XU Qianqian,FENG Chi,TIAN Xin,YUAN Zhenhua.Novel MMC sub-module for fault-blocking in all-DC grid-connected offshore wind power system[J].Electric Power Automation Equipment,2025,45(12):201-208. |
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| 摘要: |
| 基于模块化多电平换流器(MMC)的高压大功率DC/DC变换器是海上全直流风电场功率外送的关键设备。针对传统半桥子模块缺乏故障阻断能力，无法实现故障快速清除的问题，提出一种具备故障电流阻断能力的新型MMC子模块拓扑。分析DC/DC变换器直流故障电流特性，引出基于新型子模块拓扑的直流故障阻断原理，通过在故障期间将电容反向接入故障电流回路提供反电动势，实现故障隔离和短路电流抑制。与其他具备故障阻断能力的子模块拓扑相比，所提拓扑器件使用数量较少，成本低，工作损耗小。在MATLAB/Simulink中搭建仿真模型，仿真结果验证了采用该子模块的MMC-DC/DC变换器能够实现故障电流的快速阻断及故障之后的快速重启。 |
| 关键词: 海上风电全直流并网系统 模块化多电平换流器 MMC-DC/DC变换器 子模块拓扑 故障穿越 |
| DOI：10.16081/j.epae.202505013 |
| 分类号:TM721.1;TM614 |
| 基金项目:国家电网有限公司总部管理科技项目(5100-202199543A-0-5-ZN) |
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| Novel MMC sub-module for fault-blocking in all-DC grid-connected offshore wind power system |
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LIU Qihui1, XU Qianqian1, FENG Chi1, TIAN Xin2, YUAN Zhenhua2
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1.Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing 102206, China;2.State Grid Shandong Electric Power Economic & Technology Research Institute, Jinan 250021, China
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| Abstract: |
| High-voltage and high-power DC/DC converter based on the modular multilevel converter(MMC) serves as a critical component for power transmission in all-DC offshore wind farms. To address the limitations of traditional half-bridge sub-modules, which lacks fault-blocking capabilities and cannot achieve rapid fault clearance, a novel MMC sub-module topology with fault current blocking capability is proposed. The characteristics of DC fault current in the DC/DC converter are analyzed, and the DC fault-blocking mechanism based on the new sub-module topology is introduced. During the fault conditions, the capacitor is reconnected in reverse into the fault current loop to provide counter electromotive force, thereby achieving fault isolation and short-circuit current suppression. Compared with other sub-module topologies with fault-blocking ability, the proposed topology requires fewer devices, incurs lower costs, and exhibits reduced operational losses. The simulation model is constructed in MATLAB/Simulink, and the simulative results validate that the MMC-DC/DC converter employing the proposed sub-module can achieve rapid fault current blocking and quick post-fault recovery. |
| Key words: all-DC grid-connected offshore wind power system modular multilevel converter MMC-DC/DC converter sub-module topology fault ride through |
