published_or_final_version / Electrical Engineering / Master / Master of Philosophy

Thesis (M. Phil.)--University of Hong Kong, 1989.

published_or_final_version / Electrical Engineering / Master / Master of Philosophy

Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 152-158).

Thesis (MEng)--University of Stellenbosch, 2000. / ENGLISH ABSTRACT: This thesis deals with different design aspects of the multi-flux barrier rotor of the reluctance synchronous machine (RSM). The effect of the different designs on the performance of the RSM is investigated by means of two-dimensional finite element analysis. The finite element analysis is also directly used in the optimum design of the rotor of the RSM. The importance of the use of the finite element analysis in the design and performance calculations of the RSM is illustrated in this thesis. The design aspects of the RSM which are focussed on in this thesis are, amongst other things, the chording of the stator winding, the skewing of the rotor and the ratio of the number of rotor flux barriers to the number of stator slots of the RSM. The effects of these design aspects on the average torque and torque ripple of the RSM are investigated and general design directives are given. The occurrence of flux pulsations in the stator teeth and rotor iron segments of the RSM are also studied to some extent. The finite element optimum design of a4-pole RSM-rotor with a high number of flux barriers is described in the thesis. This optimum designed rotor is built and the RSM with this rotor is tested in the laboratory. Its calculated and measured performances are studied and compared with a conventional, low number rotor flux barrier RSM. It is found, amongst other things, that the RSM with the high number of rotor flux barriers has a slightly higher average torque with a significantly lower torque ripple. / AFRIKAANSE OPSOMMING: Hierdie tesis handeloor verskillende ontwerp-aspekte van die reluktansie sinchroonmasjien (RSM) met 'n multi-vloedversperringsrotor. Die effek van die verskillende ontwerpe op die vermoë van die RSM is met behulp van twee-dimensionele eindige element analise ondersoek. Die eindige element analise is ook direk in die optimum ontwerp van die rotor van die RSM gebruik. Die belangrikheid van die gebruik van die eindige element analise in die ontwerp en vermoë-berekening van die RSM word in die tesis geïllustreer. Die ontwerp-aspekte van die RSM waarop in hierdie tesis gefokus word, is onder andere die spoelsteekverkorting van die statorwikkeling, die skuinsing van die rotor en die verhouding van die getal rotor-vloedverperrings tot die getal statorgIeuwe van die RSM. Die effek van hierdie ontwerpaspekte op die gemiddelde draaimoment en draaimoment-rimpel van die RSM word ondersoek en algemene riglyne vir die ontwerp van die RSM word gegee. Die voorkoms van vloedpulsasies in die statortande en rotor yster segmente van die RSM word ook deels ondersoek. Die eindige element optimum ontwerp van 'n 4-pool RSM-rotor met 'n hoe getal vloedversperrings word in die tesis beskryf. Hierdie optimum ontwerpte rotor is gebou en die RSM met hierdie rotor is in die laboratorium getoets. Die berekende en gemete vermoë is bestudeer en vergelyk met die vermoë van 'n RSM met 'n konvensionele, lae getal vloedversperrings rotor. Dit is onder andere gevind dat die RSM met die hoë getal rotor-vloedversperrings 'n effens hoër gemiddelde draaimoment het met 'n behuidende laer draaimoment-rimpel.

Thesis (MScEng)--University of Stellenbosch, 2001. / ENGLISH ABSTRACT: The aim of this study is to critically evaluate the voltage injection position sensorless control technique as applied to the reluctance synchronous machine (RSM) drive and to implement the technique on a 5.5 kW RSM and a 110 kW RSM. The technique is evaluated by using an accurate mathematical model of the RSM in a simulation package, called Simuwin. The negative effects that cross-magnetisation and the slotted air-gap have on the technique are intensively investigated. It was showed that these effects can cause an error in the position estimation of up to 30°. The TMS320F240 DSP was used as the controller for the RSM drives to implement the position sensorless control technique. Measurements on both RSM drives confirm the simulated results. / AFRIKAANSE OPSOMMING: Die doel van hierdie tesis is om die spannings-injeksie posisie sensorlose beheer tegniek soos toegepas op die reluktansie sinchroon masjien (RSM) aandryfstelsel, krities te evalueer en te implementeer op 'n 5.5 kW RSM en op 'n 110 kW RSM. Die tegniek is geevalueer deur 'n akkurate wiskundige model van die RSM saam te stel en die model te gebruik in 'n simulasie pakket, genaamd Simuwin. Daar is veral klem gele op die negatiewe invloed wat kruis-magnetisering en 'n gegleufde lug-spleet op die tegniek het. Dit is bewys dat hierdie eienskappe van die RSM 'n fout in die posisie afskatting van tot 30° kan veroorsaak. Die TMS320F240 DSP is gebruik as beheerder vir die RSM aandryfstelsels om sodoende posisie sensorlose beheer op altwee masjiene toe te pas. Metings op albei stelsels bevestig die simulasies.

Made available in DSpace on 2014-12-02T11:16:56Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-05-16Bitstream added on 2014-12-02T11:20:51Z : No. of bitstreams: 1 000800400.pdf: 2071431 bytes, checksum: e31ebfa14029e4e6b1269a594e8fb2a2 (MD5) / Este trabalho apresenta um estudo sobre análise e controle coordenado de múltiplos dispositivos FACTS com vistas à melhoria da estabilidade transitória de Sistemas de Energia Elétrica, considerando especificamente os efeitos dos dispositivos em derivação (SVC) e em série (TCSC). As análises são feitas por métodos baseados na função energia do sistema mais especificamente na energia potencial avaliada no espaço das posições angulares dos rotores das máquinas em torno de um ponto de equilíbrio estável. A influência e a alocação dos dispositivos FACTS são avaliadas por um índice de efeito de atuação sobre a capacidade de sincronização entre os pares de máquinas, denominado fator de efeito. O controle coordenado dos múltiplos dispositivos FACTS se dá mediante sua compensação dinâmica por meio de cada uma das três leis de controle que objetivam elevar a superfície gerada pela função energia potencial do sistema que circunda o ponto de equilíbrio estável durante a primeira oscilação, denominada de vale energético, e direcionar sua trajetória para um caminho mais íngreme, idealmente na mesma orientação do gradiente da energia potencial na direção de um ponto de máximo local dificultando sua ultrapassagem pela cordilheira energética e, consequentemente, proporcionando ao sistema, melhoria das condições de estabilidade transitória observada pela elevação do tempo crítico de eliminação de uma falta. As simulações feitas nos três sistemas testes (Sistema Kundur, Sistema IEEE 14 Barras e Sistema New England) foram usadas para avaliar o controle proposto. Conclui-se que cada uma das leis de controle proposta contribui, de forma similar, na melhoria da estabilidade transitória de Sistemas de Energia Elétrica / This thesis presents a study about coordinated analysis and control over multiple FACTS devices with the objective of improving the transient stability of Electric Power Systems, considering specifically, the effects of the devices in derivation (SVC) and in series (TCSC). The analysis are made by methods based on the system energy function, more specifically on the potential energy evaluated in the angular positions’ space from the rotors of machines around a stable balance position. The influence and location of FACTS devices are evaluated by a performance effect index over the synchronization capacity between pairs of machines, called effect factor. The coordinated control over multiple FACTS devices is possible through it’s dynamic compensation by means of each one of the three laws of control whose objective is to elevate the surface generated by the system potential energy function of the system which surrounds the stable balance point during the first oscillation, named energy valley. The system trajectory is conduced to a steeper way, ideally on the same orientation as the gradient of the potential energy towards a single point of a function local max so hardening it’s passage through the energy barrier. The improvements on the transient stability’s conditions observed by elevation of the critical time of a fault elimination. The simulations done on the three test systems (Kundur System, IEEE 14 Bars System and New England) System were used to evaluate the proposed control. It follows that each of the proposed control laws contributes similarly, improving transient stability of Electric Electric Systems

Orientador: Laurence Duarte Colvara / Banca: Carlos Roberto Minussi / Banca: Percival Bueno de Araujo / Banca: Igor Kopcak / Banca: Carlos Roberto Mendonça da Rocha / Resumo: Este trabalho apresenta um estudo sobre análise e controle coordenado de múltiplos dispositivos FACTS com vistas à melhoria da estabilidade transitória de Sistemas de Energia Elétrica, considerando especificamente os efeitos dos dispositivos em derivação (SVC) e em série (TCSC). As análises são feitas por métodos baseados na função energia do sistema mais especificamente na energia potencial avaliada no espaço das posições angulares dos rotores das máquinas em torno de um ponto de equilíbrio estável. A influência e a alocação dos dispositivos FACTS são avaliadas por um índice de efeito de atuação sobre a capacidade de sincronização entre os pares de máquinas, denominado fator de efeito. O controle coordenado dos múltiplos dispositivos FACTS se dá mediante sua compensação dinâmica por meio de cada uma das três leis de controle que objetivam elevar a superfície gerada pela função energia potencial do sistema que circunda o ponto de equilíbrio estável durante a primeira oscilação, denominada de vale energético, e direcionar sua trajetória para um caminho mais íngreme, idealmente na mesma orientação do gradiente da energia potencial na direção de um ponto de máximo local dificultando sua ultrapassagem pela cordilheira energética e, consequentemente, proporcionando ao sistema, melhoria das condições de estabilidade transitória observada pela elevação do tempo crítico de eliminação de uma falta. As simulações feitas nos três sistemas testes (Sistema Kundur, Sistema IEEE 14 Barras e Sistema New England) foram usadas para avaliar o controle proposto. Conclui-se que cada uma das leis de controle proposta contribui, de forma similar, na melhoria da estabilidade transitória de Sistemas de Energia Elétrica / Abstract: This thesis presents a study about coordinated analysis and control over multiple FACTS devices with the objective of improving the transient stability of Electric Power Systems, considering specifically, the effects of the devices in derivation (SVC) and in series (TCSC). The analysis are made by methods based on the system energy function, more specifically on the potential energy evaluated in the angular positions' space from the rotors of machines around a stable balance position. The influence and location of FACTS devices are evaluated by a performance effect index over the synchronization capacity between pairs of machines, called effect factor. The coordinated control over multiple FACTS devices is possible through it's dynamic compensation by means of each one of the three laws of control whose objective is to elevate the surface generated by the system potential energy function of the system which surrounds the stable balance point during the first oscillation, named energy valley. The system trajectory is conduced to a steeper way, ideally on the same orientation as the gradient of the potential energy towards a single point of a function local max so hardening it's passage through the energy barrier. The improvements on the transient stability's conditions observed by elevation of the critical time of a fault elimination. The simulations done on the three test systems (Kundur System, IEEE 14 Bars System and New England) System were used to evaluate the proposed control. It follows that each of the proposed control laws contributes similarly, improving transient stability of Electric Electric Systems / Doutor

Advanced material handling systems' impact on flexible manufacturing systems (FMS) have increased the efficiency and work rate over conventional manufacturing assemblies. The interaction of automated guided vehicles (AGVs), roller conveyors and conveyor belts with robots and machine tools forms highly sophisticated assembly operations. Whilst material handling in FMS today is conventionally used to transport assembly units from one work station to another, it does not take an active role in the manufacturing process. With manufacturers implementing more advanced manufacturing principles to perform agile manufacturing, there is a growing need to implement "smarter" material handling systems that would perform essential, integral roles in the assembly process. This research outlines the development of a cordless linear synchronous motor (CLSM) material handling system. The CLSM incorporates a permanent magnet courier that moves without tether restrictions on an integrated reverse air bearing system which eliminates friction. The CLSM provides a material handling system with enhanced travel, flexibility and accuracy. The CLSM material handling system is designed to integrate with overhead manipulators and part feeders to form a comprehensive flexible manufacturing system. This research covers the 2-D finite element modeling (FEM) used to determine the CLSM's optimal parameters. The development of the motor windings design and construction, together with the control system for the CLSM, is also covered. The CLSM novel air bearing system is outlined and compared to other conventional linear bearing systems. The possible impact of the CLSM on current manufacturing systems is explored to determine the validity of the research project and possible further research opportunities. / Thesis (M.Sc.Eng)-University of Natal, Durban, 2000.

Orientador: Ernesto Ruppert Filho / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-15T03:55:20Z (GMT). No. of bitstreams: 1 PeqquenaSuni_JuanCarlos_M.pdf: 1533933 bytes, checksum: dbd348c759114d83f69069e35635591c (MD5) Previous issue date: 2009 / Resumo: Os parâmetros do modelo matemático dinâmico dos geradores síncronos como a resistência elétrica dos enrolamentos de estator por fase, a resistência elétrica do enrolamento de campo, as resistências elétricas dos enrolamentos amortecedores de eixo direto e de eixo em quadratura, as reatâncias de dispersão dos enrolamentos de estator por fase, do enrolamento de campo e dos enrolamentos amortecedores, bem como as reatâncias de magnetização de eixo direto e de eixo em quadratura do gerador são possíveis de serem determinadas, com razoável aproximação, através de ensaios específicos como o ensaio para determinação da reatância de Potier, o ensaio de curto-circuito trifásico brusco e os ensaios de rejeição de carga. Neste trabalho discute-se o problema da determinação de parâmetros do gerador síncrono auxiliado pela realização de simulações dinâmicas usando o software Matlab/Simulink e a sua biblioteca SimPowerSystems para determinação de parâmetros de um gerador de pólos lisos e de um gerador de pólos salientes através de ensaios de medição da reatância síncrona de eixo direto, ensaio de Potier, ensaio de curto-circuito brusco e ensaio de rejeição de carga. Diversos resultados e conclusões são apresentados usando os parâmetros padronizados mostrados explicitamente por Krause em seu importante livro publicado em 1986. Trata-se de um trabalho que tem finalidades didática e tecnológica de discutir essa questão / Abstract: The synchronous generator dynamic mathematical model parameters like the per phase stator winding electrical resistance, the field winding resistance, the direct and quadrature damping winding resistances, the field winding leakage reactance, the per phase stator winding leakage reactance, the damping winding leakage reactances, and direct and quadrature magnetizing reactances are possible to be determined with some accuracy through specific tests like the Potier reactance determination, the sudden short-circuit test and the load rejection tests. This work is addressed to the problem of salient poles and cylincrical rotor synchronous generator parameters determination aided by the use of dynamic simulations implemented with the Matlab/Simulink package using its SimPowerSystems library. Some results and conclusions about the parameters determination are presented using the standardized and fundamental parameters as shown in the Krause book published in 1986. This paper has both didactic and technological subjects and it is addressed to discuss several aspects on the real parameters determination activities / Mestrado / Energia Eletrica / Mestre em Engenharia Elétrica