New modified staircase modulation and capacitor balancing strategy of 21-level modular multilevel converter for HVDC transmission systems

K. H. Ahmed, G. P. Adam

Research output: Chapter in Book/Report/Conference proceedingConference contribution

6 Citations (Scopus)

Abstract

In this paper, a modified staircase modulation is proposed which enables more efficient use of the DC link voltage. This is very preferable feature for HVDC transmission systems as the 15% lower DC link voltage can be used (lower number of cells). In the second part of the paper the capacitor balancing of modular multilevel converter (MMC) converter is investigated. Balancing becomes a significant issue when the number of the converter levels is high. For instance, with a 401-level MMC converter, the converter comprises 400 cells per arm per phase. This means that 2400 capacitors have to be measured and fed back to the controller for balancing. The system will not be only impractical but also unreliable and complex. A new capacitor balancing strategy is proposed to enhance the system reliability and eliminate the capacitor voltage sensors. A simple example of 7-level converter is presented to explain basic principles of the proposed technique. The proposed method performance is validated by studying a 21-level MMC based VSC-HVDC system.

Original languageEnglish
Title of host publication7th IET International Conference on Power Electronics, Machines and Drives
Subtitle of host publication PEMD 2014
PublisherInstitution of Engineering and Technology
Pages1-6
Number of pages6
Volume2014
ISBN (Electronic)9781849198158
DOIs
Publication statusPublished - Jun 2014
Event7th IET International Conference on Power Electronics, Machines and Drives, PEMD 2014 - Manchester, United Kingdom
Duration: 8 Apr 201410 Apr 2014

Conference

Conference7th IET International Conference on Power Electronics, Machines and Drives, PEMD 2014
CountryUnited Kingdom
CityManchester
Period8/04/1410/04/14

Keywords

  • Balancing
  • HVDC
  • MMC
  • Staircase
  • VSC

ASJC Scopus subject areas

  • Electrical and Electronic Engineering

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  • Cite this

    Ahmed, K. H., & Adam, G. P. (2014). New modified staircase modulation and capacitor balancing strategy of 21-level modular multilevel converter for HVDC transmission systems. In 7th IET International Conference on Power Electronics, Machines and Drives: PEMD 2014 (Vol. 2014, pp. 1-6). Institution of Engineering and Technology. https://doi.org/10.1049/cp.2014.0420