Reliability Analysis of MMCs Considering Submodule Designs with Individual or Series-Operated IGBTs


The half-bridge-based modular multilevel converter (MMC) has emerged as the favored converter topology for voltage-source HVDC applications. The submodules within the converter can be constructed with either individual insulated-gate bipolar transistor (IGBT) modules or with series-connected IGBTs, which allows for different redundancy strategies to be employed. The main contribution of this paper is that an analytical method was proposed to analyze the reliability of MMCs with the consideration of submodule arrangements and redundancy strategies. Based on the analytical method, the relative merits of two approaches to adding redundancy, and variants created by varying the submodule voltage, are assessed in terms of overall converter reliability. Case studies were conducted to compare the reliability characteristics of converters constructed using the two submodule topologies. It is found that reliability of the MMC with series-connected IGBTs is higher for the first few years but then decreases rapidly. By assigning a reduced nominal voltage to the series valve submodule upon IGBT module failure, the need to install redundant submodules is greatly reduced.

Publication DOI:
Divisions: College of Engineering & Physical Sciences
Funding Information: This work was supported in part by the National Natural Science Foundation of China under Grant 51261130471; in part by EPSRC under Grants EP/K006312/1, EP/I031707/1, and EP/I013636/1; and in part by the China Scholarship Council (201406280115). Paper no.
Additional Information: This work is licensed under a Creative Commons Attribution 3.0 License. For more information, see
Uncontrolled Keywords: Modular multilevel converter (MMC),reduced nominal voltage operation,redundancy analysis,reliability assessment,voltage capability,Energy Engineering and Power Technology,Electrical and Electronic Engineering
Publication ISSN: 1937-4208
Last Modified: 12 Feb 2024 08:30
Date Deposited: 30 Aug 2019 09:14
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Related URLs: http://www.scop ... tnerID=8YFLogxK (Scopus URL)
https://ieeexpl ... ocument/7479573 (Publisher URL)
PURE Output Type: Article
Published Date: 2017-04-01
Published Online Date: 2016-05-26
Accepted Date: 2016-05-12
Authors: Guo, Jingli (ORCID Profile 0000-0002-4648-435X)
Liang, Jun
Zhang, Xiaotian
Judge, Paul D.
Wang, Xiuli
Green, Tim C.



Version: Published Version

License: Creative Commons Attribution

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