Active thermal balancing for modular multilevel converters in HVDC applications

Frederik Hahn, Giampaolo Buticchi, Marco Liserre

Research output: Chapter in Book/Conference proceedingConference contributionpeer-review

17 Citations (Scopus)

Abstract

The modular multilevel converter (MMC) has become a very attractive solution for interfacing high voltages hybrid networks. The MMC enables scalability to different power levels, full controllability provided by IGBTs and can achieve very high efficiencies by using a low switching frequency method as the nearest level modulation (NLM). However, in order to limit failures of the power modules, the thermal stress of the submodules (SMs) should be properly studied. For NLM a capacitor voltage balancing algorithm is required and this algorithm, as demonstrated in this paper, offers already good thermal balance among the cells of the MMC. However, at low power factor, operation which could occur in case of low-voltage ride through and of reactive power injection, the mentioned algorithm is not effective anymore. This paper proposes an active thermal balancing algorithm which is embedded in the previously mentioned capacitor voltage balancing algorithm. The purpose of the active balancing is to achieve an equal heat distribution among the submodules to enhance the lifetime. The junction temperatures with and without active thermal balancing are studied in simulation for an HVDC application. The paper proves that thermal balance of MMC can be significantly improved.

Original languageEnglish
Title of host publication2016 18th European Conference on Power Electronics and Applications, EPE 2016 ECCE Europe
PublisherInstitute of Electrical and Electronics Engineers Inc.
ISBN (Electronic)9789075815245
DOIs
Publication statusPublished - 25 Oct 2016
Externally publishedYes
Event18th European Conference on Power Electronics and Applications, EPE 2016 ECCE Europe - Karlsruhe, Germany
Duration: 5 Sep 20169 Sep 2016

Publication series

Name2016 18th European Conference on Power Electronics and Applications, EPE 2016 ECCE Europe

Conference

Conference18th European Conference on Power Electronics and Applications, EPE 2016 ECCE Europe
Country/TerritoryGermany
CityKarlsruhe
Period5/09/169/09/16

Keywords

  • HVDC
  • High voltage power converters
  • Multilevel converters
  • Thermal cycling
  • Thermal stress

ASJC Scopus subject areas

  • Energy Engineering and Power Technology
  • Electrical and Electronic Engineering

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