Thesis (MSc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: The design optimisation of a linear oscillatory electric generator for application in freepiston
Stirling engines is described in this thesis.
A basic overview of free-piston Stirling engine technology is given by firstly providing a
brief description of the operation of the heat engine. The applications of free-piston Stirling
engines in industry are given and the proposed future applications are described.
Different types of electrical machine designs from industry and academia are evaluated
in a literature study. A classification structure is also proposed based on the magnetic flux
variation within the designs.
Based on the literature study, a transverse flux, single-phase, moving magnet, tubular
topology was chosen for investigation.
Athree dimensional finite element simulation was chosen as the most appropriatemethod
to model the linear electrical machine. A commercial simulation package was called from
a simulation script and the outputs from the finite element simulation were again used to
calculate the electrical machine performance parameters using the instantaneous voltageand
current values.
A sequential quadratic programming algorithm was used to perform optimisation of
the machine topologies, with the optimisation variables being dimensional parameters that
describe the machine geometry and the goal of the optimisation to minimise the active mass
of the machine, while maintaining preset minima for the output power and the efficiency.
The machine was optimised for a number of different translator configurations and the
different configurations were analysed and compared. It was found that a quasi-Halbach
arrangement of the permanent magnets yielded the lowest overall active mass. A comparative
study is also presented, where this quasi-Halbach variant is compared to a commercial
machine. It was found that the linear machine design with a quasi-Halbach arrangement
compares well with the commercial machine.
A prototype and test bed was designed and constructed. Due to manufacuring difficulties
however, the machine could not be completed in time for testing. / AFRIKAANSE OPSOMMING: Die ontwerpsoptimering van ’n lineêre ossillerende elektriese generator vir toepassing in
vrysuier Stirling enjins word beskryf in hierdie tesis.
’n Basiese oorsig van vrysuier Stirling enjin tegnologie word gegee deur eerstens ’n kort
beskrywing te gee van die werking van die hitte-enjin. Die aanwending van vrysuier Stirling
enjins in industrie word gegee en voorgestelde toekomstige toepassings word beskryf.
Verskillende tipes elektriese masjien ontwerpe vanuit die industrie en die akademie word
geëvalueer in ’n literatuurstudie. ’n Klassifiseringstruktuur, gebaseer op die magnetiese
vloedverandering in die ontwerpe, word ook voorgestel.
’n Transverse vloed, enkelfase, bewegende magneet, tubulêre topologie is gekies vir die
ondersoek, gebaseer op die onder andere die literatuurstudie.
’n Drie-dimensionele eindige element simulasie is gekies as die mees geskikte metode
om die lineêre elektriese masjien te modelleer. ’n Kommersiële simulasie pakket is deur
middel van ’n simulasie skrip geroep en die uitsette vanaf die eindige element simulasie is
weer gebruik om die werksverrigtingsparameters van die elektriese masjien te bereken deur
gebruik te maak van die oomblikswaardes van die spanning en stroom.
’n Sekwensiële kwadratiese programmering algoritme is gebruik om optimering van
die masjien topologieë te doen, met die dimensionele parameters wat die masjien geometrie
beskryf as die optimeringsveranderlikes en doel van die optimering om die aktiewe
massa van die masjien te minimeer, terwyl die uitsetdrywing en die benuttingsgraad by
voorafgestelde minima gehou word.
Die masjien is geoptimeer vir verskeie translator konfigurasies en die verskillende konfigurasies
is geanaliseer en vergelyk. Dit is bevind dat ’n kwasi-Halbach skikking van die
permanente magnete die laagste totale aktiewe massa gelewer het. ’n Vergelykende studie
is ook aangebied, waar die kwasi-Halbach variant vergelyk is met ’n kommersiële masjien.
Dit is bevind dat die lineêre masjien met die kwasi-Halbach skikking baie goed vergelyk
met die kommersiële masjien.
’n Prototiepe masjien en toetsopstelling is ontwerp en aan mekaar gesit. Maar as gevolg
van vervaardigbaarheids tekortkominge kon toetse op die prototiepe nie betyds gedoen
word nie.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/96849 |
| Date | 03 1900 |
| Creators | Joubert, Louis Hoogenhout |
| Contributors | Strauss, Johann M., 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 | Unknown |
| Type | Thesis |
| Format | xii, 175 pages : illustrations |
| Rights | Stellenbosch University |
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