A Postfault Strategy to Control the Modular Multilevel Converter Under Submodule Failure

作者：Yang Qichen^*; Qin Jiangchao; Saeedifard Maryam

来源：IEEE Transactions on Power Delivery, 2016, 31(6): 2453-2463.

DOI：10.1109/TPWRD.2015.2449875

• Modular multilevel converter (MMC)
• neutral shift
• postfault strategy

The modular multilevel converter ( MMC) has become one of the most promising topologies for high-voltage applications. Although the MMC has a modular and redundant structure, which can significantly enhance its reliability and fault tolerance, its fault handling capability can be further improved by adopting a postfault strategy. In this paper, a postfault strategy based on the neutral-shift method is proposed, which, subsequent to bypassing the faulty submodule( s), aims at improving the maximum attainable line-to-line voltages of the MMC. Based on a newly developed internal variable analysis method, the impact of the neutral-shift strategy on the operation of the MMC is analyzed. In conjunction with the proposed postfault strategy, a modified circulating current suppression ( CCS) method is used to mitigate the double-frequency component of the circulating currents. Performance and effectiveness of the proposed neutral-shift strategy with and without the CCS method is evaluated based on time-domain simulation studies in the PSCAD/EMTDC software environment.

• 出版日期2016-12