一种新型模块化多电平换流器

柔性直流输电技术应用于架空线路场合面临的关键问题是如何实现直流线路故障的快速隔离,一般认为采用全桥拓扑的换流器是较好的方案。文中提出一种基于类全桥子模块的新型模块化多电平换流器(SFBSM-MMC),与采用全桥的换流器相比,该新型换流器在同样实现直流线路故障快速隔离的同时,还兼具了经济性。介绍了SFBSM-MMC的拓扑结构、工作模式和直流故障隔离原理,并对其基本控制策略、预充电策略和直流线路故障隔离策略进行了设计,最后通过仿真验证了预充电策略和直流线路故障隔离策略的可行性。仿真结果表明,SFBSM-MMC在快速隔离直流线路故障方面具有优良的性能,适合基于架空线路的柔性直流输电工程应用。

A Novel Modular Multilevel Converter

Regarding the application of voltage source converter-based high voltage direct current (VSC-HVDC) technology to the overhead line with modular multilevel converter (MMC) topology, the key problem is how to isolate DC line fault rapidly. It is generally believed that the converter based on full bridge is a good solution. A new type of MMC is presented based on simple full bridge submodule (SFBSM-MMC) which, while retaining the DC line fault isolating ability, is cost-effective. The topology, basic control strategy, charging strategy and DC line fault isolating strategy of SFBSM-MMC are designed. Finally, the charging strategy and DC line fault isolating strategy are verified by simulation. Results show that the SFBSM-MMC is suitable for VSC-HVDC projects based on overhead line for its good performance in the rapid isolation of DC line fault. This work is supported by National High Technology Research and Development Program of China (863 Program) (No. 2013AA050106, No. 2015AA050101).