Wind Turbine and slip permanent magnet coupler design analysis for small scale fixed speed wind generator systems

Dumakude, Niniva (2018-03)

Thesis (MScEng)--Stellenbosch University, 2018.

Thesis

ENGLISH ABSTRACT: Very recently has the concept of a slip coupler been introduced in wind energy applications. It forms part of the SS-PMG and there is extensive work being done in evaluating the technology. It's application is for a fixed speed and fixed blade pitch stall controlled wind turbine. The stall controlled wind turbine's aerodynamic performance is evaluated using BEM and CFD for various wind conditions where the gust winds are evaluated in case they pose a potential threat in the health of the system components. The optimum energy capture for proposed wind site is established and a cost analysis is performed in order to establish what size turbine and cost would yield optimum energy production per cost. A cost model for the SS-PMG system is proposed whereby a discrete cost package for the slip-PMC and the PMSG are developed, with the use of mass ratios of the SS-PMG components and some data from electrical machines manufacturers. A simple cost model for the wind turbine blades is established and with the available cost models, the drive train cost evaluation is performed in evaluating the competitiveness of the Aero Energy and the NREL Phase VI wind turbine. To minimise shaft stifiness, the slip-PMC is introduced in small-scale wind turbines. The analysis of such machines is proposed and evaluated. A spoke-mount PM coupler configuration is proposed and its performance is evaluated against that of the the surface-mount PM coupler which is widely studied in most literature. The machine performance sensitivity to magnet dimensions is done in a form of a optimisation of a PM rotor for a fixed wound rotor. The spoke-mount PM machine shows an improvement in torque performance for the same amount of PM material as the surface-mount PM machine. The slip-PMC torque performance is dependent on the effective resistance of the coils, thus assuming dc resistance only yields inaccurate prediction, especially at high frequencies. Thus slot leakage effect is accounted by introducing a multiple layer coil modelling technique whereby the average taken when only one coil layer is considered is minimised. Additionally the ac resistance is dominant where the skin depth of penetration is less than the actual coil depth, thus it is deemed necessary to evaluate the model performance assuming ac resistance at high slip frequencies. The low core loss which is deemed negligible in the design optimisation of such a machine is demonstrated using a static and time harmonic model. The conduction losses which are quite dominant and accounted for in the design optimisation are illustrated. Finally the slip-PMC concept is tested test rig prototype which shows is in agreement with the static FEM analysis method, in effect validating the slip-PMC concept.

AFRIKAANSE OPSOMMING: Baie onlangs is die konsep van 'n glipkoppelaar in windenergie-toepassings bekendgestel. Dit vorm deel van die SS-PMG en daar word uitgebreide werk gedoen om die tegnologie te evalueer. Dit is die toepassing van 'n vaste spoeden- vaste-mes-stalletjie beheerde windturbine. Die aërodinamiese prestasie van die stalletriese windturbine word geëvalueer met behulp van BEM en CFD vir verskeie windtoestande waar die windwinde geëvalueer word in die geval dat dit 'n potensiële bedreiging in die gesondheid van die stelselkomponente inhou. Die optimale energie-opname vir die voorgestelde windterrein word vasgestel en 'n koste-analise word uitgevoer om vas te stel watter grootte turbine en koste optimale energieproduksie per koste sal lewer. 'N Kostemodel vir die SS-PMG-stelsel word voorgestel waarvolgens 'n diskrete kostepakket vir die slip-PMC en die PMSG ontwikkel word, met behulp van massaverhoudings van die SS-PMG komponente en sommige data van vervaardigers van elektriese masjiene. 'N Eenvoudige kostemodel vir die windturbine-lemme word gevestig. Met die beskikbare kostemodelle word die koste-evaluering van die treinkoste uitgevoer om die mededingendheid van die Aero Energy en die wind turbine van die NREL Fase VI te evalueer. Om die styfheid van die skag te verminder, word die slip-PMC in kleinschalige windturbines ingevoer. Die ontleding van sulke masjiene word voorgestel en geëvalueer. 'N Spreek-berg-PM-koppelaarkonfigurasie word voorgestel en sy prestasie word geëvalueer teen dié van die oppervlakmonteer-PM-koppelaar wat in die meeste literatuur wyd bestudeer word. Die masjienprestasie sensitiwiteit vir magneet afmetings word gedoen in 'n vorm van 'n optimalisering van 'n PM rotor vir 'n vaste wondrotor. Die geperforeerde PM-masjien toon 'n verbetering in wringkragprestasie vir dieselfde hoeveelheid PM-materiaal as die oppervlakmonterende PM-masjien. Die glip-PMC-wringkragprestasie is afhanklik van die effektiewe weerstand van die spoele, dus aanvaar die dc weerstand slegs onakkurate voorspelling, veral by hoë frekwensies. So die slot lek effek word verantwoord deur die invoering van 'n meervoudige laag spoel modellering tegniek waardeur die gemiddelde geneem wanneer slegs een spoel laag oorweeg word, word geminimaliseer. Daarbenewens is die AC-weerstand dominante waar die veldigtheid van die penetrasie minder is as die werklike spoeldiepte. Dit word dus nodig geag om die modelprestasie te evalueer met die aanvaarding van AC-weerstand teen hoë glyfrekwensies. Die lae kernverlies wat onbeduidend geag word in die ontwerpoptimalisering van so 'n masjien word gedemonstreer met behulp van 'n statiese en tyd harmoniese model. Die geleidelike verliese wat heeltemal oorheersend en verantwoord word in die ontwerpoptimalisering word geïllustreer. Ten slotte word die slip-PMC-konsep getoets met die toets-prototipe wat toon dat dit in ooreenstemming is met die statiese FEM-analise-metode, wat die slip-PMC-konsep uiteindelik bevestig.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/103684
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