Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: The electromagnetic and mechanical design aspects of optimally designed doublesided rotor radial flux permanent magnet wind generators with non-overlap aircored (iron-less) stator windings are analysed in this thesis. The wind generator is implemented in a battery charging system for use in rural settlements and farms. The optimal generator and system design is based on an accurate analytical model and is confirmed with finite element analysis. It is shown, amongst other things, that the electromagnetic design and surprisingly not the mechanical design, determines the rotor yoke dimensions and, hence, largely the mass and cost of the generator. Alternative battery charging systems are also considered and discussed. / AFRIKAANSE OPSOMMING: Die elektromagnetiese en meganiese ontwerp aspekte van optimaal ontwerpte dubbel-kant rotor radiale vloed permanente magneet windgenerators met nieoorvleuelende lug kern (sonder yster) statorwindings word in hierdie tesis ontleed. Die windgenerator word geplaas in 'n battery-laai stelsel vir gebruik in landelike nedersettings en plase. Die optimale generator en die stelsel ontwerp is gegrond op 'n akkurate analitiese model en is bevestig met eindige element analise. Daar word onder andere getoon dat die elektromagnetiese ontwerp, en nie die meganiese ontwerp, die rotor juk dimensies en dus grootliks die massa en die koste van die generator, bepaal. Alternatiewe battery-laai stelsels word ook oorweeg en bespreek.

Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2011. / Due to finite oil resources and its political and economical impact, a renewed interest in energy independence has compelled industry and government to pursue electric vehicle designs. The current worldwide research that is being conducted on drivetrain topologies for EVs, focus mainly on direct in-wheel drive, direct differential drive and fixed-gear differential drive topologies. Furthermore, the control strategy for these type of motor drives require a, so called, field-weakening operation in order to achieve acceptable performance characteristics for the vehicle. This thesis evaluates the use of a manual gearbox drivetrain topology and a radial flux air-cored permanent magnet (RFAPM) synchronous machine, without flux-weakening operation, as a traction drive application for EVs. For the purpose of this research study, a 2006 model Opel Corsa Lite is converted to a battery electric vehicle, and the Corsa is renamed to the E-Corsa. The Corsa is converted so that all the original functionality, boot space and space inside the vehicle are retained. The original 5-speed manual gearbox is used as drivetrain for the vehicle and a 40 kW, 70 Nm RFAPM traction drive is developed for the manual gearbox. A power electronic converter is designed for RFAPM traction drive and a Lithium ion (Li-ion) battery pack is used as energy source for the traction drive. The battery pack is mounted partially in the front and partially in the back of the vehicle to maintain an even weight distribution in the vehicle.

Thesis (PhD)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: In this dissertation a new type of electrical machine, a Radial Flux Air-Cored Permanent Magnet machine with a Double-sided Rotor and utilising concentrated, non-overlapping windings, is proposed. The concept of the Double-sided Rotor Radial Flux Air-Cored Permanent Magnet machine, or RFAPM machine for short, was derived from the Double-sided Rotor Axial Flux Air-Cored Permanent Magnet (AFAPM) machine. One of the problems that AFAPM machines experience, is the deflection of the rotor discs due to the strong magnetic pull of the permanent magnets, especially with double-sided rotor machines. The main advantage of a RFAPM machine over a AFAPM machine is that the rotor back-iron is cylindrically shaped instead of disk shaped. Due to the structural integrity of a cylinder, the attraction force between the two rotors does not come into play any more. The focus of this dissertation is on a thorough analytical analysis of the Double-Sided Rotor RFAPM machine. With the RFAPM being an air-cored machine, the feasibility to develop a linear, analytical model, to accurately predict the radial flux-density and hence the induced EMF in the stator windings, as well as the accurate calculation of the developed torque of the machine, needed to be investigated. The need for a thorough analytical examination of the Double-Sided Rotor RFAPM machine stemmed from the need to reduce the blind reliance on Finite Element Modelling (FEM) software to calculate the back-EMF and torque produced by these machines. Another problem experienced with the FEM software was to obtain accurate torque results. Excessive ripple torque oscillations were sometimes experienced which took a considerable amount of time to minimise with constant refinement to the meshing of the machine parts. Reduction in the mesh element size unfortunately also added to the simulation time. The requirement for an accurate analytical model of the RFAPM machine was also necessary in order to reduce the amount of time spent on successive FEM simulation to obtain the optimum pole arc width of the permanent magnet in order to minimise the harmonic content of the radial flux-density distribution in the the stator windings. In this dissertation, the use of single-layer and double-layer, non-overlapping, concentrated winding for the RFAPM machine is also investigated. It was decided to include a comparison of these two non-overlapping winding configurations with a “hypothetical” concentrated, overlapping winding configuration. This would allow us to gauge the effectiveness of using nonoverlapping winding with respect to the reduction in copper losses as well as in the reduction in copper volume. It would also allow us to investigate the extent of how much the developed torque is affected by using non-overlapping windings instead of overlapping windings. / AFRIKAANSE OPSOMMING: In hierdie proefskrif word ’n nuwe tipe elektriese masjien, ’n Radiale-vloed Lugkern Permanent Magneet Masjien met ’n dubbelkantige rotor en nie-oorvleuelende Windings voorgestel. Die konsep vir die Radiale-vloed Lugkern Permanent Magneet Masjien, of RVLPM vir kort, is afgelei vanaf die Dubbelkantige Rotor, Aksiale-vloed Lugkern (AVLPM) masjien. Een van die probleme wat met AVLPM masjiene ondervind word, is die defleksie van die rotorjukke as gevolg van die sterk aantrekkingskragte van die permanente magnete, veral in dubbelkantige rotor masjiene. Die hoof voordeel wat die RVLPM masjien inhou bo die AVLPM masjien, is die feit dat die RVLPM se rotorjukke silindries is in plaas van ronde skywe. As gevolg van die strukturele integriteit van ’n silinders, speel die aantrekkingskrag van die permanente magnete nie meer ’n rol nie. Die fokus van die proefskrif gaan oor die deeglike analitiese analise van die dubbelkantige RVLPM masjien. Weens die feit dat die RVLPM masjien ’n lugkern masjien is, is daar besluit om ondersoek in te stel na die moontlikheid om ’n lineêre, analitiese model vir die masjien op te stel waarmee die radiale-vloeddigtheid, teen-EMK asook die ontwikkelde draaimoment vir die masjien akkuraat bereken kan word. Die behoefde aan ’n akkurate analitiese model vir die dubbelkantige rotor RVLPM masjien is om die blinde vertroue te elimineer wat daar in Eindige-Element Modellering (EEM) sagteware gestel word om die teen-EMK en ontwikkelde draaimoment van die RVLPM masjien uit te werk. ’n Verdere probleem wat daar met EEM sagteware ondervind is, is die akkurate berekening van die ontwikkelde draaimoment. Oormatige rimpel draaimoment ossillasies is soms ondervind wat heelwat tyd geverg het om te minimeer, deur voortdurende verfyning van die EEM maas in die verskillende dele van die masjien. Soos die maas egter kleiner word, verleng dit die simulasie tyd van die EEM aansienlik. Nog ’n rede vir ’n akkurate analitiese model van die RVLPM masjien, is om vinnige metode te verkry om die optimale permanente magneet pool hoekwydte te verkry, wat die minste Totale Harmoniese Vervorming (THV) in die radiale-vloeddigtheidsdistribusie in die statorgebied sal veroorsaak, sonder om herhaaldelike EEM simulasies te loop. In die proefskrif word die gebruik van enkellaag en dubbellaag, nie- oorvleuelende, gekonsentreerde wikkelings vir die RVLPM masjien ook ondersoek. Daar is besluit om hierdie twee nie-oorvleuelende windingskonfigurasies met ’n “hipotetiese” gekonsentreerde, oorvleuelende windingskonfigurasie te vergelyk. Dit behoort ons in staat te stel om die doeltreffendheid van nie-oorvleuelende windings te bepaal, met betrekking tot die afname in koperverliese asook die afname in kopervolume. Verder sal dit ons in staat stel om ook mate waartoe die ontwikkelde draaimoment deur nie-oorvleuelende windings beïnvloed word, te ondersoek.

Thesis dissertate power reactors and analyses techniques of an air-core power coils and inductors with ferromagnetic circuit and an air gap. Construction of the inductors verified the accuracy of the calculated values against the measured parameters. According to the outcome of this analysis, corrections of the design process are derived. Thesis design optimization to minimize size, weight, efficiency and in comparsion of these two factoctors.