Operation of a hybrid modular multilevel converter during grid voltage unbalance

Amankwah, Emmanuel K.; Watson, Alan James; Clare, Jon C.

Abstract

© The Institution of Engineering and Technology. The recently proposed parallel hybrid modular multilevel converter is considered to be a low loss, low component count converter with soft switching capability of the 'main' H-bridge. The converter has similar advantages to other emerging modular multilevel converter circuits being considered for high-voltage, direct current power transmission and can be made compact which is desirable for offshore application. However, during ac network unbalance the individual 'chain-links' (CL) exchange unequal amounts of power with the grid which requires appropriate remedial action. This study presents research into the performance of the converter and proposes a suitable control method that enables the converter to operate during grid voltage unbalance. The proposed control concept involves the use of asymmetric third harmonic voltage generation in the 'CL' of the converter to redistribute the power exchanged between the individual 'CL' and the grid. Mathematical analysis and simulation modelling with results are presented to support the work described.

Citation

Amankwah, E. K., Watson, A. J., & Clare, J. C. (2016). Operation of a hybrid modular multilevel converter during grid voltage unbalance. IET Generation, Transmission and Distribution, 10(12), 3102-3110. https://doi.org/10.1049/iet-gtd.2015.0766

• Journal Article Type: Article
• Acceptance Date: Jun 2, 2016
• Online Publication Date: Sep 2, 2016
• Publication Date: Sep 2, 2016
• Deposit Date: Oct 13, 2016
• Publicly Available Date: Oct 13, 2016
• Journal: IET Generation, Transmission & Distribution
• Print ISSN: 1751-8687
• Electronic ISSN: 1751-8695
• Publisher: Institution of Engineering and Technology (IET)
• Peer Reviewed: Peer Reviewed
• Volume: 10
• Issue: 12
• Pages: 3102-3110
• DOI: https://doi.org/10.1049/iet-gtd.2015.0766
• Keywords: Offshore installations; HVDC power transmission; Power system harmonics
• Public URL: https://nottingham-repository.worktribe.com/output/819357
• Publisher URL: http://digital-library.theiet.org/content/journals/10.1049/iet-gtd.2015.0766
• Additional Information: This paper is a postprint of a paper submitted to and accepted for publication in IET Generation, Transmission and Distribution and is subject to Institution of Engineering and Technology Copyright. The copy of record is available at IET Digital Library
• Contract Date: Oct 13, 2016