Circulating current suppression of the modular multilevel converter in a double-frequency rotating reference frame

Behrooz Bahrani, Suman Debnath, Maryam Saeedifard

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63 Citations (Scopus)


The modular multilevel converter (MMC) has attracted significant interest for medium-/high-power energy conversion applications due to its modularity, scalability, and excellent harmonic performance. One of the technical challenges associated with the operation of the MMC is the circulation of double-frequency harmonic currents within its phase legs. This paper proposes a circulating current control strategy in a double-frequency rotating reference frame, which, contrary to the existing solutions that are based on approximate/inaccurate models, relies on an experimentally identified nonparametric model of circulating currents to determine the coefficients of the controller. Minimizing the squared second norm of the error between the open-loop transfer function of the system and a desired one, the coefficients of the controller are determined. To guarantee the stability of the closed-loop system, the minimization problem is subjected to a few constraints. The validity and effectiveness of the proposed control strategy is confirmed, and its dynamic performance is compared with that of an existing solution by experimental results.
Original languageEnglish
Article number7046433
Pages (from-to)783-792
Number of pages10
JournalIEEE Transactions on Power Electronics
Issue number1
Publication statusPublished - Jan 2016
Externally publishedYes

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