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Due to the insecurity of the supply of raw materials needed for neodymium-iron-boron magnets, typically used in permanent magnet generators, the use of ferrite magnets as an alternative was investigated. The investigation was conducted by attempting to redesign a generator that previously used neodymium-iron-boron magnets for use with ferrite magnets. The major part of the redesign was to find an alternate rotor design with an electromagnetic design adapted to the characteristics of the ferrite magnets.It was found that  ferrite magnets can be used to replace neodymium-iron-boron magnets with changes to the electromagnetic design of the rotor. The changes of the electromagnetic design increase the amount of magnetically active material in the rotor and, therefore, require the mechanical design of the rotor to be changed. The new rotor design also requires some changes to the generator support structure. A design for a replacement rotor, using ferrite magnets, along with the required changes to the support structure, is presented.

<p>In this thesis, a concept for a modular assembly direct drive permanent magnetgenerator is presented. The maximum forces that act on the different parts of thegenerator during normal operation have been calculated and used in solid mechanicsimulations in SolidWorks. The result is a rough first draft of a generator designwhere the stator has been divided into five modules and the rotor into six modules.This division is done in order to avoid symmetries in the generator that could lead toproblems with self-oscillation.The modulization of the stator brings about certain difficulties, both for the magneticcircuit and for the winding scheme. Different solutions for optimization of themagnetic circuit are analyzed from both a physical and a construction technicalperspective. A winding scheme is produced and the winding process tested in awinding dummy produced according to the conceptual generator design.</p>

In this thesis, a concept for a modular assembly direct drive permanent magnetgenerator is presented. The maximum forces that act on the different parts of thegenerator during normal operation have been calculated and used in solid mechanicsimulations in SolidWorks. The result is a rough first draft of a generator designwhere the stator has been divided into five modules and the rotor into six modules.This division is done in order to avoid symmetries in the generator that could lead toproblems with self-oscillation.The modulization of the stator brings about certain difficulties, both for the magneticcircuit and for the winding scheme. Different solutions for optimization of themagnetic circuit are analyzed from both a physical and a construction technicalperspective. A winding scheme is produced and the winding process tested in awinding dummy produced according to the conceptual generator design.

Within the existing available mix of numerical and analytical thermal analysis options, lumped parameter thermal modelling is selected as the operational backbone to develop an improved novel synchronous generator thermal modelling package. The objective is for the creation of a user friendly quick feedback tool, which can serve as a means to make quick machine design thermal calculations and answer customer queries quickly and reliably. Furthermore, thermally improved generator designs will allow for inevitable operational losses to be channelled away from the machine more efficiently. As a result, machine component temperatures will be reduced, allowing lower generator thermal ratings. The end result will be smaller, longer lasting, more efficient generators, with the ability to be adapted with greater ease to particular applications. With the contribution of selected numerical analysis techniques, mainly finite element analysis for the distribution of iron losses, the MySolver thermal modelling package is developed and presented in this thesis. It is this combination of numerical and analytical tools that improves synchronous generator thermal modelling accuracy, but ultimately it is the lumped parameter nature of the thermal models developed that makes MySolver succeed as a reliable quick feedback electrical machine thermal design tool, validated using experimental results for a wide range of operating conditions. The initial part of the thesis analyses the electrical machine thermal modelling techniques available today, indicating advantages and disadvantages associated with each one, and providing a rationale for the selection of lumped parameter modelling to be used by MySolver. The development of the synchronous generator lumped parameter thermal models is detailed, with examples on its construction presented. Subsequently, finite element analysis is utilised to predict the distribution of machine iron losses across the rotor and stator laminations, with the findings applied to MySolver. Furthermore, a study is performed into the lumped parameter discretisation level needed to effectively represent machine windings. MySolver is experimentally verified using experimental data from a fully instrumented synchronous generator and this data is also used to obtain further insight into the temperature distribution within the generator. In the final part results are evaluated and the use of MySolver for modelling and optimising electrical machines is discussed. Finally, appropriate conclusions on the work presented are drawn.

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.

This work deals with calculation and design of synchronous salient pole generator and then the transformation from this machine into so-called hybrid synchronous machine is described. This diploma thesis is done for company Siemens Electric Machines s.r.o. in Drásov. This company provided their design of synchronous salient pole generator. The model of this generator was created in programs RMxprt and Maxwell 2D. Suggestions and models were compared, and their calculated parameters were evaluated. The created model was upgraded to so-called hybrid synchronous generator. Permanent magnets were added in the created model and influence of these additional magnets is going to be analyzed. Tasks of the work are described in more details. in the introduction. The topic of synchronous generator and hybrid synchronous generator in general is described in the theoretical part. The next part of work deals with the design of salient pole generator. In the other part of the work calculation and design of the generator model are described in Ansys program. Furthermore there are some results from program compared with the results from company. Some model parts and other graphic outputs from Ansys program are shown. After that the creation of hybrid synchronous generator is described and created models of hybrid synchronous generators are compared and evaluated.

This project is focused on software design and implementation. This software represents a generator of web information system source code developed in ASP.NET 2.0. The information system requires the SQL database. The source code generated by this application is the base of the next development in Visual Studio 2008. This project inspects similar generators too.