The Alternate Arm Converter (AAC) - "short-overlap" mode operation - analysis and design parameter selection

Farr, Ewan; Feldman, Ralph; Clare, Jon C.; Watson, Alan James; Wheeler, Patrick

Abstract

This paper presents converter operation principles and theoretical analyses for “short-overlap” mode operation of the Alternate Arm Converter (AAC), which is a type of modular multilevel Voltage Source Converter (VSC) that has been proposed for HVDC transmission applications. Fourier series expressions for the ideal arm current and reference voltage are derived, for the first time, in order to develop an expression for the sub-module capacitance required to give a selected peak-peak voltage ripple of the summed sub-module capacitor voltages in an arm. The DC converter current contains non-negligible low order even harmonics; this is verified by deriving, for the first time, a Fourier series expression for this current. As the DC converter current needs to be filtered to form a smooth DC grid current, a novel DC filter arrangement is proposed, which uses the characteristics of a simplified DC cable model, as well as the capacitance of the DC link and additional DC link damping resistance, in order to form a passive low pass filter. Results obtained from a simulation model, which is based on an industrial HVDC demonstrator, are used in order to verify the presented converter operation principles and theoretical analyses.

Citation

Farr, E., Feldman, R., Clare, J. C., Watson, A. J., & Wheeler, P. (2018). The Alternate Arm Converter (AAC) - "short-overlap" mode operation - analysis and design parameter selection. IEEE Transactions on Power Electronics, 33(7), 5641-5659. https://doi.org/10.1109/TPEL.2017.2742899

• Journal Article Type: Article
• Acceptance Date: Aug 5, 2017
• Online Publication Date: Aug 21, 2017
• Publication Date: Jul 1, 2018
• Deposit Date: Sep 15, 2017
• Publicly Available Date: Sep 15, 2017
• Journal: IEEE Transactions on Power Electronics
• Print ISSN: 0885-8993
• Electronic ISSN: 0885-8993
• Publisher: Institute of Electrical and Electronics Engineers
• Peer Reviewed: Peer Reviewed
• Volume: 33
• Issue: 7
• Pages: 5641-5659
• DOI: https://doi.org/10.1109/TPEL.2017.2742899
• Keywords: AC-DC power conversion, DC-AC power conver¬sion, HVDC converters, HVDC transmission, Multilevel systems
• Public URL: https://nottingham-repository.worktribe.com/output/960964
• Publisher URL: http://ieeexplore.ieee.org/document/8013805/
• Additional Information: © 2017 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works