A post-fault strategy to control the modular multilevel converter under submodule failure

Qichen Yang, Jiangchao Qin, Maryam Saeedifard

Research output: Contribution to journalArticle

27 Scopus citations


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 faulttolerance, its fault handling capability can be further improved by adopting a post-fault strategy. In this paper, a post-fault strategy based on the neutral-shift method is proposed, which, subsequent to bypassing the faulty SM(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 post-fault 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 neutralshift strategy with and without the CCS method is evaluated based on time-domain simulation studies in the PSCAD/EMTDC software environment.

Original languageEnglish (US)
Article number7150419
JournalIEEE Transactions on Power Delivery
Issue number99
StatePublished - 2015


  • Modular Multilevel Converter (MMC)
  • Neutral-Shift
  • Post- Fault Strategy

ASJC Scopus subject areas

  • Energy Engineering and Power Technology
  • Electrical and Electronic Engineering

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