Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: The digital control of UPS systems has been difficult in the past due to a lack of DSP technology. It was for
this reason not possible to establishing the necessary control to regulate the voltages and currents of the UPS
systems. Recent advances in DSP technology have however provided the means of establishing central
control of the UPS system as well as incorporating more complex closed-loop control algorithms by utilising
a single floating-point DSP.
Closed-loop control strategies are investigated and the central control of a line-interactive UPS is established
in this study. Both the status of the physical system as well as various system parameters are controlled. The
system both regulates and charges the storage batteries when the main utility supply is maintained. In the
event that the utility fails, the converter instantaneously changes power flow towards the load with the aim of
maintaining an uninterrupted voltage supply.
Several closed-loop deadbeat based control strategies are investigated for the regulation of the inductor
current. A solution for the regulation of the DC-link is also developed and implemented. Furthermore, an
intensive study is done on the regulation of the voltage supplied to the load in the event that the utility supply
fails. The investigation is initially approached by considering classical control theory. Although these control
strategies provided sufficient results, a predictive strategy that is based on the physical conditions of the
switching converter is finally investigated to establish closed loop control of the output voltage. This resulted
in a high-bandwidth voltage controller capable of maintaining control under a wide-array of load conditions. / AFRIKAANSE OPSOMMING: Die digitale beheer van UPS stelsels was moeilik in the verlede as gevolg van 'n gebrek aan DSP tegnologie.
Dit was vir hierdie rede nie moontlik om beheer te kon bewerkstelling ten einde die spannings and strome in
the UPS stelsels te kon reguleer nie. Onlangse vordering in DSP tegnologie het egter dit moontlik gemaak
om sentrale beheer van die UPS stelsel te bewerkstellig sowel as om meer komplekse geslote lus beheer
algoritmes te inkorporeer met behulp van 'n enkele DSP.
Geslote lus beheer strategiëe word ondersoek en die sentrale beheer van die line-interaktiewe UPS word
bewerkstellig in hierdie studie. Beide die huidige toestand van die fisiese stelsel sowel as die verskeie
parameters word beheer. Die stelsel beide laai en reguleer die batterye terwyl die hooftoevoer onderhou
word. In die geval dat die hooftoevoer faal, word die omsetter se rigting van drywingsvloei verander om die
las te voorsien van 'n ononderbroke spannings toevoer.
Verskeie geslote-lus “deadbeat” beheer strategiëe word ondersoek vir die regulasie van die induktor stroom.
'n Oplossing vir die regulasie van die GS-koppervlak word ook ontwikkel en geïmplementeer. Verder word
'n intensiewe studie gedoen op regulasie van die spanning wat aan die las gevoer word in die geval dat die
hooftoevoer faal. Hierdie ondersoek word aanvanklik benader deur klassieke beheer teorie te bestudeer.
Alhoewel hierdie beheer strategiëe voldoene resultate gebied het, was 'n voorspel beheerstrategie gebaseer
op die fisiese toestand van die omsetter finaal ondersoek. Die resultaat is 'n hoë-bandwydte spannings
beheerder wat daartoe instaat is om beheer te handhaaf onder 'n verskeidenheid van lastoestande.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/6537 |
| Date | 03 1900 |
| Creators | Van Papendorp, J. F. |
| Contributors | Beukes, H. J., 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 | Unknown |
| Type | Thesis |
| Format | 148 p. : ill. |
| Rights | University of Stellenbosch |
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