Thesis (PhD (Electrical and Electronic Engineering))--University of Stellenbosch, 2011. / AFRIKAANSE OPSOMMING: Hierdie proefskrif handel oor die natuurlike balanserings meganismes van veelvlakkige
en modulêre omsetters wat fase-skuif dragolf puls wydte modulasie gebruik.
Die meganismes kan in twee hoof groepe verdeel word: ‘n swak balanserings
meganisme wat afhanklik is van die oorvleuling van die skakelfunksies en ‘n
sterk meganisme wat voorkom ongeag of die skakelfunksies oorvleul al dan nie.
Die sterk meganisme verdeel verder in twee subgroepe, ‘n direkte oordrag van onbalans
energie en ‘n meganisme wat afhang van die verliese in die stelsel. Elkeen
van die meganismes word aan die hand van ‘n omsetter topologie waarin die spesifieke
meganisme oorheers beskryf en ontleed. In die ondersoek word klem geplaas
op die daarstelling van uitdrukkings om die tydskonstantes van herbalansering na
’n afwyking vir elk van die omsetter toplologieë te beskryf. / ENGLISH ABSTRACT: This thesis investigates the natural balancing mechanisms in multilevel and modular
converters using phase shifted carrier pulse width modulation. Two groups
of mechanisms are identified; a weak balancing mechanism that is only present
when the switching functions are interleaved and a strong mechanism that occurs
irrespective of the interleaving of the switching functions. It is further shown that
the strong balancing mechanism can be divided into a balancing mechanism that
depends on the direct exchange of unbalance energy and a loss based balancing
mechanism. Each of the mechanisms is discussed and analysed using a converter
where the specific mechanism dominates as example. Emphasis is placed on the
calculation of the rebalancing time constant following a perturbation. Closed form
expressions for the rebalancing time constants for each of the analysed converters
are presented.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/6791 |
| Date | 03 1900 |
| Creators | Van der Merwe, Johannes Wilhelm (Wim) |
| Contributors | Mouton, H. du T., University of Stellenbosch. Faculty of Engineering. Dept. of Electrical and Electronic Engineering. |
| Publisher | Stellenbosch : University of Stellenbosch |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | English |
| Type | Thesis |
| Format | 250 p. : ill. |
| Rights | University of Stellenbosch |
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