Operation of a hybrid modular multilevel converter during grid voltage unbalance

Amankwah, Emmanuel K. and Watson, Alan James and Clare, Jon C. (2016) Operation of a hybrid modular multilevel converter during grid voltage unbalance. IET Generation, Transmission & Distribution, 10 (12). pp. 3102-3110. ISSN 1751-8695

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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 HVDC power transmission and can be made compact which is desirable for offshore application. However, during ac network unbalance the individual ‘chain-links’ exchange unequal amounts of power with the grid which requires appropriate remedial action. This paper 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 ‘chain-links’ of the converter to redistribute the power exchanged between the individual ‘chain-links’ and the grid. Mathematical analysis and simulation modelling with results are presented to support the work described.

Item Type: Article
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
Keywords: Offshore installations; HVDC power transmission; Power system harmonics
Schools/Departments: University of Nottingham UK Campus > Faculty of Engineering > Department of Electrical and Electronic Engineering
Identification Number: https://doi.org/10.1049/iet-gtd.2015.0766
Depositing User: Burns, Rebecca
Date Deposited: 13 Oct 2016 14:13
Last Modified: 15 Oct 2016 16:39
URI: http://eprints.nottingham.ac.uk/id/eprint/37543

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