Picture of neon light reading 'Open'

Discover open research at Strathprints as part of International Open Access Week!

23-29 October 2017 is International Open Access Week. The Strathprints institutional repository is a digital archive of Open Access research outputs, all produced by University of Strathclyde researchers.

Explore recent world leading Open Access research content this Open Access Week from across Strathclyde's many research active faculties: Engineering, Science, Humanities, Arts & Social Sciences and Strathclyde Business School.

Explore all Strathclyde Open Access research outputs...

Analysis and design of a modular multilevel converter with trapezoidal modulation for medium and high voltage dc-dc transformers

Gowaid, I. A. and Adam, Grain P. and Ahmed, Shehab and Holliday, Derrick and Williams, Barry W. (2015) Analysis and design of a modular multilevel converter with trapezoidal modulation for medium and high voltage dc-dc transformers. IEEE Transactions on Power Electronics, 30 (10). pp. 5439-5457. ISSN 0885-8993

[img]
Preview
Text (Gowaid-etal-IEEETPE-2015-Analysis-and-design-of-a-modular-lutlilevel-converter-with-trapezoidal-modulation)
06977967.pdf - Final Published Version
License: Creative Commons Attribution 4.0 logo

Download (2MB) | Preview

Abstract

Conventional dual active bridge topologies provide galvanic isolation and soft-switching over a reasonable operating range without dedicated resonant circuits. However, scaling the two-level dual active bridge to higher dc voltage levels is impeded by several challenges among which the high dv/dt stress on the coupling transformer insulation. Gating and thermal characteristics of series switch arrays add to the limitations. To avoid the use of standard bulky modular multilevel bridges, this paper analyzes an alternative modulation technique where staircase approximated trapezoidal voltage waveforms are produced; thus alleviating developed dv/dt stresses. Modular design is realized by the utilization of half-bridge chopper cells. Therefore, the analyzed converter is a modular multi-level converter operated in a new mode with no common-mode dc arm currents as well as reduced capacitor size, hence reduced cell footprint. Suitable switching patterns are developed and various design and operation aspects are studied. Soft switching characteristics will be shown to be comparable to those of the two-level dual active bridge. Experimental results from a scaled test rig validate the presented concept.