Thesis (MScEng)--Stellenbosch University, 2001. / ENGLISH ABSTRACT: This thesis deals with the design and evaluation of a 300 kW double stage axial-flux
permanent magnet generator with an ironless stator. The magnetic and electrical
design equations are derived for sinewave and quasi-squarewave axial-flux permanent
magnet machines. The thermal design approach used is also described. The machine
is optimised for maximum torque per current loading. A Matlab program code is
developed to do the necessary calculations in the design optimisation and the
calculation of the machine parameters.
Mechanical finite element simulations are conducted to investigate the severity of the
magnetic attraction force between the rotor discs. The results obtained from the
simulations suggested an increase in the yoke thickness in order to withstand the
attraction force. The construction of the prototype machine's rotor and stator is
described. The flux density in the airgap is thoroughly investigated through
measurements and analysis. Thermal measurements are also conducted to investigate
the effect of eddy currents in the stator winding. Furthermore, no-load measurements
conducted on the 300 kW machine showed that the machine has a serious problem of
circulating currents in the parallel connected coils. Possible solutions for this are
investigated and recommendations are given. Due to the circulating current problem
and the relative high eddy current losses, it was not possible to do full-load tests on
the machine. / AFRIKAANSE OPSOMMING: Hierdie tesis handeloor die ontwerp en evaluering van 'n multi-stadium Aksiale Vloed Permanente Magneet (AFPM) masjien met 'n ysterlose stator. Die magnetiese - en
elektriese ontwerp-vergelykings is afgelei vir sinusgolf en quasi vierkantsgolf AFPM
masjiene. Die termiese ontwerp word ook bespreek. Die masjien is geoptimeer vir
maksimum draairnoment per stroombelasting. Daar is 'n program-kode in Matlab
geskryf om die nodige berekeninge vir die optimering van die masjien uit te voer en
vir die bepaling van die masjien-parameters. Meganiese eindige element berekenings is gedoen om die invloed van die magnetiese aantrekkingskrag tussen die rotorskywe te ondersoek. Die resultate het aangedui dat
die rotorskyfdikte nie die magnetiese aantrekkingskrag van die magnete kan
weerstaan nie en moes in dikte vedubbel word. Die konstruksie van die masjien se
rotor en stator is behandel. Die vloeddigtheid in die luggaping is noukeurig ondersoek
deur metings en analise. Termiese metings is ook gedoen om die invloed van die
werwel strome in die statorwikkelings te ondersoek. Verder het die nullas-toetse wat
gedoen is op die masjien, aangedui dat die masjien 'n ernstige probleem het met
sirkuierende strome in die parallelle geleiers van die statorspoele. Moontlike
oplossings is ondersoek en aanbevelings word gegee. Dit was nie moontlik om
vollastoetse op die masjien te doen nie, as gevolg van die probleem met sirkuierende
strome en die relatiefhoë werwelstoom-verliese in die statorwikkelings.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/52177 |
| Date | 12 1900 |
| Creators | Mbidi, David Natangue |
| Contributors | Kamper, M. J., Stellenbosch University. Faculty of Engineering. Dept. of Electrical and Electronic Engineering. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | English |
| Type | Thesis |
| Format | 84 p. : ill. |
| Rights | Stellenbosch University |
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