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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
481

Estudo de máquina elétrica de fluxo axial aplicada a sistema de tração automotiva com acoplamento direto e frenagem regenerativa

Goltz, Evandro Claiton January 2012 (has links)
Este trabalho descreve o desenvolvimento e caracterização de uma máquina elétrica para aplicação em sistemas de tração automotiva. Compreende o estudo e a análise do perfil de carga e das grandezas eletromagnéticas e eletromecânicas através da construção de modelos analíticos, numéricos e experimentais. Através destes, são propostos critérios para o dimensionamento geométrico e para a escolha dos materiais. A topologia da máquina elétrica possui fluxo axial no entreferro, duplo rotor com ímãs permanentes setoriais, núcleo estator toroidal sem ranhuras e enrolamentos setoriais. Os modelos analíticos tridimensionais para a geometria e o volume dos enrolamentos são uma contribuição relevante em termos científicos. Experimentalmente, a máquina é acionada como gerador síncrono, com um rendimento interno de até 91,75%. Como gerador em regime de frenagem regenerativa obteve-se um rendimento interno de 78,61% no barramento CC. Ao final, utilizando o modelo automotivo de perdas, é feita uma análise em regime permanente do sistema acoplado, visando à caracterização da eficiência energética global do sistema. Os resultados obtidos permitem uma avaliação adequada da máquina no modo de operação proposto. / Este trabalho descreve o desenvolvimento e caracterização de uma máquina elétrica para aplicação em sistemas de tração automotiva. Compreende o estudo e a análise do perfil de carga e das grandezas eletromagnéticas e eletromecânicas através da construção de modelos analíticos, numéricos e experimentais. Através destes, são propostos critérios para o dimensionamento geométrico e para a escolha dos materiais. A topologia da máquina elétrica possui fluxo axial no entreferro, duplo rotor com ímãs permanentes setoriais, núcleo estator toroidal sem ranhuras e enrolamentos setoriais. Os modelos analíticos tridimensionais para a geometria e o volume dos enrolamentos são uma contribuição relevante em termos científicos. Experimentalmente, a máquina é acionada como gerador síncrono, com um rendimento interno de até 91,75%. Como gerador em regime de frenagem regenerativa obteve-se um rendimento interno de 78,61% no barramento CC. Ao final, utilizando o modelo automotivo de perdas, é feita uma análise em regime permanente do sistema acoplado, visando à caracterização da eficiência energética global do sistema. Os resultados obtidos permitem uma avaliação adequada da máquina no modo de operação proposto.
482

Estudo de máquina elétrica de fluxo axial aplicada a sistema de tração automotiva com acoplamento direto e frenagem regenerativa

Goltz, Evandro Claiton January 2012 (has links)
Este trabalho descreve o desenvolvimento e caracterização de uma máquina elétrica para aplicação em sistemas de tração automotiva. Compreende o estudo e a análise do perfil de carga e das grandezas eletromagnéticas e eletromecânicas através da construção de modelos analíticos, numéricos e experimentais. Através destes, são propostos critérios para o dimensionamento geométrico e para a escolha dos materiais. A topologia da máquina elétrica possui fluxo axial no entreferro, duplo rotor com ímãs permanentes setoriais, núcleo estator toroidal sem ranhuras e enrolamentos setoriais. Os modelos analíticos tridimensionais para a geometria e o volume dos enrolamentos são uma contribuição relevante em termos científicos. Experimentalmente, a máquina é acionada como gerador síncrono, com um rendimento interno de até 91,75%. Como gerador em regime de frenagem regenerativa obteve-se um rendimento interno de 78,61% no barramento CC. Ao final, utilizando o modelo automotivo de perdas, é feita uma análise em regime permanente do sistema acoplado, visando à caracterização da eficiência energética global do sistema. Os resultados obtidos permitem uma avaliação adequada da máquina no modo de operação proposto. / Este trabalho descreve o desenvolvimento e caracterização de uma máquina elétrica para aplicação em sistemas de tração automotiva. Compreende o estudo e a análise do perfil de carga e das grandezas eletromagnéticas e eletromecânicas através da construção de modelos analíticos, numéricos e experimentais. Através destes, são propostos critérios para o dimensionamento geométrico e para a escolha dos materiais. A topologia da máquina elétrica possui fluxo axial no entreferro, duplo rotor com ímãs permanentes setoriais, núcleo estator toroidal sem ranhuras e enrolamentos setoriais. Os modelos analíticos tridimensionais para a geometria e o volume dos enrolamentos são uma contribuição relevante em termos científicos. Experimentalmente, a máquina é acionada como gerador síncrono, com um rendimento interno de até 91,75%. Como gerador em regime de frenagem regenerativa obteve-se um rendimento interno de 78,61% no barramento CC. Ao final, utilizando o modelo automotivo de perdas, é feita uma análise em regime permanente do sistema acoplado, visando à caracterização da eficiência energética global do sistema. Os resultados obtidos permitem uma avaliação adequada da máquina no modo de operação proposto.
483

Controle de um filtro ativo de potência bifásico a três fios utilizando a teoria p-q monofásica

Furtado, Pablo Carlos de Siqueira 27 June 2014 (has links)
Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-04-24T20:26:56Z No. of bitstreams: 1 pablocarlosdesiqueirafurtado.pdf: 4055605 bytes, checksum: b23cd5bfadf3eb9e69e3e5e804322231 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-04-25T15:21:49Z (GMT) No. of bitstreams: 1 pablocarlosdesiqueirafurtado.pdf: 4055605 bytes, checksum: b23cd5bfadf3eb9e69e3e5e804322231 (MD5) / Made available in DSpace on 2017-04-25T15:21:49Z (GMT). No. of bitstreams: 1 pablocarlosdesiqueirafurtado.pdf: 4055605 bytes, checksum: b23cd5bfadf3eb9e69e3e5e804322231 (MD5) Previous issue date: 2014-06-27 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Esta dissertação apresenta uma estratégia para controlar um filtro ativo de potência (FAP) paralelo bifásico a três fios. A aplicação desse FAP pode ser implementada como uma funcionalidade extra do conversor fonte de tensão do sistema de propulsão de veículos elétricos (VE), o que seria útil para compensar instalações elétricas residenciais e comerciais com fornecimento de energia bifásico a três fios. Apresenta-se o princípio de funcionamento do FAP bifásico e é tratada sua modelagem matemática. É feita uma revisão dos conceitos de potências instantâneas p e q em sistemas monofásicos, a chamada teoria p–q monofásica. É mostrada ainda a interpretação dessas grandezas e sua relação com as potências ativa e reativa convencionais. Em seguida, são feitas adaptações na implementação dessa teoria. A principal adaptação está na forma de implementar as transformações αβ monofásicas. Com essas adaptações, a teoria p–q modificada é utilizada para descrever o algoritmo de controle desenvolvido para o FAP bifásico. A estratégia de compensação adotada consiste na compensação de todas as componentes harmônicas de corrente, da potência reativa e na equalização das correntes nas fases envolvidas. São apresentados resultados obtidos em estudos de simulação da operação do FAP bifásico em regime permanente e sob transitórios das cargas. O trabalho mostra ainda alguns resultados experimentais do FAP em operação. Conclui-se que os resultados obtidos validam o princípio de operação do FAP bifásico e a estratégia de controle proposta. / This thesis presents an strategy to control a two–phase, three-wire shunt active power filter (APF). This APF can be implemented as an extra functionality of the embedded voltage source converter in the propulsion system of an electric vehicle (EV). This application would be useful in the compensation of residential and commercial electrical installations fed by a two–phase three–wire grid connection. The working principle of shunt two-phase APF is presented and its mathematical models are also treated. Concepts of the instantaneous powers p and q, called single-phase p–q theory, are reviewed. The relationship between these quantities and the conventional active and reactive powers is discussed. Then, some adaptations are done in the implementation of such theory. The main one is related to the implementation method of singlephase αβ transformations. After these adaptations, the modified p–q theory is used to described the developed algorithm to control the two–phase APF. The adopted control strategy consists of compensating all current harmonics and reactive power, as well as equalizing currents in involved phases. Simulation results are presented to show the APF operation in steady-state and under load changes. Yet, some experimental results are presented to show the APF in operation. The obtained results validate the presented working principle and the control strategy proposed in this thesis.
484

Modelagem e controle de trajetória de um veículo robótico terrestre de exterior / Modeling and path tracking control of an outdoor robotic ground vehicle

Cordeiro, Rafael de Angelis, 1986- 22 August 2018 (has links)
Orientador: Ely Carneiro de Paiva / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-22T23:12:16Z (GMT). No. of bitstreams: 1 Cordeiro_RafaeldeAngelis_M.pdf: 9321021 bytes, checksum: ff7bb113095dc020ed982e7d7c28311a (MD5) Previous issue date: 2013 / Resumo: Veículos terrestres autônomos tem recebido uma atenção especial dos estudos de robótica nos últimos anos. Suas aplicações incluem segurança na condução, exploração de locais inóspitos e automatização agrícola. O enfoque deste trabalho situa-se no projeto VERO, em parceria com o CTI, e tem por objetivo o desenvolvimento de aplicações de controle de trajetória para um veículo do tipo todo-terreno. Para tal, um modelo completo (dinâmico e tridimensional) é desenvolvido, com uma atenção especial para os modelos de interação entre solo e pneu, responsáveis pelas forças não lineares atuantes sobre o veículo. Em seguida, dois modelos reduzidos e linearizados são obtidos e estes são utilizados para a síntese de controladores LQR. Uma comparação entre os controladores é realizada e a resposta de um deles é detalhada para uma análise sobre a influência das características do modelo veicular sobre o controle do veículo. Por fim, três abordagens são propostas para melhorar a resposta obtida pelos controladores / Abstract: Autonomous ground vehicles have received special attention from robotics studies in past years. Their applications include advanced driver assistance systems (ADAS), exploration of inhospitable environments and harvest autonomous machines. In partnership with CTI, this master's thesis focuses in the development of path tracking controllers applied to off-road vehicles. In order to simulate vehicle characteristics, a complete three-dimensional nonlinear dynamic model was proposed with emphasis on tire-road interaction models, which are responsible for most of the vehicle's nonlinearities. In sequence, two vehicle reduced linear models are presented and applied to synthesize LQR controllers, whose results are compared. One of them was chosen to analyze the effect of vehicles's three-dimensional dynamics on path tracking control. Finally, three different approaches are proposed to enhance controllers performance / Mestrado / Planejamento de Sistemas Energeticos / Mestre em Engenharia Mecânica
485

Commande robuste de machines à réluctance variable pour la traction de véhicules électriques / robust control of a switched reluctance machine intended for electrical vehicle Propulsion.

Ouddah, Nadir 23 September 2015 (has links)
Le moteur à réluctance variable (MRV) est en train de gagner beaucoup d'intérêt dans les applications de traction électrique grâce à la compatibilité significative entre ses caractéristiques naturelles et les exigences de l'industrie automobile. Cependant, à cause de la caractéristique fortement non linéaire des grandeurs électromagnétiques du MRV, l'usure du moteur, les variations paramétriques dues aux tolérances de fabrication, et la dérive des paramètres durant le fonctionnement, les stratégies de commande classique ne permettent pas d'assurer des hautes performances de suivi de trajectoire et de robustesse en stabilité dans l'environnement de fonctionnement d'un véhicule électrique. Dans ce contexte, le premier objectif de cette thèse est de proposer des stratégies de commande robustes du MRV en prenant en considération les contraintes imposées par les applications de traction. Afin d'atteindre cet objectif, une structure de commande en cascade, composée d'une boucle externe de vitesse et d'une boucle interne de courant, est envisagée. Les objectifs de synthèse sont ensuite fixés à travers un cahier des charges formulé en termes de gabarits fréquentiels, et les correcteurs robustes et adaptatifs de vitesse et de courant sont ainsi synthétisés en se basant sur les approches de commande H-infini et LPV/H- infini. La faisabilité des correcteurs constitue également un critère important dans les applications de traction électrique où la puissance de calcul embarqué dans le véhicule est très limitée. Ce critère est pris en considération dans cette thèse à travers l'utilisation des approches de synthèse des correcteurs H- infini d'ordre fixe. Les performances de ces correcteurs sont analysées et comparées avec les performances des correcteurs H- infini classiques à travers une étude par la μ-analyse de la robustesse en stabilité et une évaluation expérimentale. Le deuxième objectif de ces travaux de thèse est d'évaluer l'intérêt de la commande sans capteurs mécanique du MRV en se basant sur des méthodes d'estimation. Des observateurs robustes basés sur les modes glissants et le filtrage de Kalman sont ainsi synthétisés. Les performances et la robustesse de ces observateurs sont ensuite comparées expérimentalement dans une perspective d'une application de traction électrique. / The switched reluctance motor (SRM) is gaining much interest in electric vehicle applications. It includes robustness to harsh operational conditions, rugged structure, fault tolerant operation and a wide range of speed. However, due to the highly nonlinear electromagnetic characteristic, wear and tear of motor, manufacturing tolerances and parameters drift during operation, classical control strategies do not ensure high dynamical performance and robustness under various operating conditions in electric vehicle environment. In this context, the first purpose of this thesis is to propose robust control strategies of the SRM taking into account the constraints imposed by electric vehicle applications. To achieve this objective, a cascade control scheme is adopted; it consists of an outer speed loop and an inner current loop. Controllers design aims are fixed through specifications formulated in frequency domain, robust and adaptive controllers of speed and currents are thus synthesized based on H- infini and LPV/H- infini control approaches. Feasibility of these controllers is also an important criterion in electric vehicles applications where embedded computing power is very limited. This criterion is taken into account in this thesis by using fixed order controller synthesis approaches. The performances of these controllers are analyzed and compared with the performances of standard H- infini controllers through an experimental evaluation and a robustness analysis is performed using the concept of the Singular Structured Value, i.e. the μ-analysis. The second objective of this thesis is to assess the interest of the sensorless control of SRM. Robust observers based on second order sliding mode (SMO2) and Kalman filtering techniques (EKF) are designed to estimate the mechanical states of SRM. Performances and robustness of these observers are then compared experimentally in perspective of electric vehicle application.
486

Contribution à la modélisation thermique de packs batteries LiFePO4 pour véhicules décarbonés / Study for the thermal modeling of low-carbon vehicle LiFePO4 battery packs

Damay, Nicolas 11 December 2015 (has links)
Cette thèse s’inscrit dans la problématique mondiale qu’est la gestion de l’énergie en se focalisant sur les batteries pour véhicules électriques ou hybrides. Celles-ci subissent des contraintes particulièrement sévères qui les font s’échauffer rapidement. Afin d’éviter le risque d’un vieillissement prématuré tout en limitant les surcoûts, il convient de dimensionner la batterie et son système de refroidissement de manière optimale. Les modèles thermiques proposés permettent ce dimensionnement optimal. Le modèle utilisé pour les pertes électriques a été amélioré pour être désormais stable lors de simulations de longs trajets. L’analyse fine du fort couplage entre les phénomènes thermiques et électrochimiques a mené à de nouvelles méthodes de caractérisations. Le « découplage » de ces phénomènes permet d’améliorer grandement les prédictions des modèles, notamment dans des plages de fonctionnement très contraignantes (basse température et très forte puissance). La précision est garantie à 1 °C, même pour des simulations de plusieurs heures. / This PhD thesis is included in the global energy-management issue. lts focus is on battery packs for electric or hybrid vehicles. The latter are bound to heat quickly because they're receiving high stresses during operation. Thus, to avoid accelerating the aging process while maintaining a minimal cost, the battery and its cooling system have to be sized optimally. The proposed thermal models can be used to reach this optimal sizing. The electrical losses model has been improved to become stable during the simulations of long driving cycles. The precise study of the strong coupling between electrochemical and thermal behaviors has led to new characterization methods. The "decoupling" of these phenomena improves significantly the models predictions, especially in very stressed operation ranges (low temperature and high power).The precision is better than 1° C, even for several-hours simulations.
487

Hybrid Power System Intelligent Operation and Protection Involving Plug-in Electric Vehicles

Ma, Tan 02 April 2015 (has links)
Two key solutions to reduce the greenhouse gas emissions and increase the overall energy efficiency are to maximize the utilization of renewable energy resources (RERs) to generate energy for load consumption and to shift to low or zero emission plug-in electric vehicles (PEVs) for transportation. The present U.S. aging and overburdened power grid infrastructure is under a tremendous pressure to handle the issues involved in penetration of RERS and PEVs. The future power grid should be designed with for the effective utilization of distributed RERs and distributed generations to intelligently respond to varying customer demand including PEVs with high level of security, stability and reliability. This dissertation develops and verifies such a hybrid AC-DC power system. The system will operate in a distributed manner incorporating multiple components in both AC and DC styles and work in both grid-connected and islanding modes. The verification was performed on a laboratory-based hybrid AC-DC power system testbed as hardware/software platform. In this system, RERs emulators together with their maximum power point tracking technology and power electronics converters were designed to test different energy harvesting algorithms. The Energy storage devices including lithium-ion batteries and ultra-capacitors were used to optimize the performance of the hybrid power system. A lithium-ion battery smart energy management system with thermal and state of charge self-balancing was proposed to protect the energy storage system. A grid connected DC PEVs parking garage emulator, with five lithium-ion batteries was also designed with the smart charging functions that can emulate the future vehicle-to-grid (V2G), vehicle-to-vehicle (V2V) and vehicle-to-house (V2H) services. This includes grid voltage and frequency regulations, spinning reserves, micro grid islanding detection and energy resource support. The results show successful integration of the developed techniques for control and energy management of future hybrid AC-DC power systems with high penetration of RERs and PEVs.
488

Green Marketing - a Case for Electric Vehicles / Zelený Marketing: Elektrické Automobily

Humbatova, Maya January 2013 (has links)
Afterwards the last 'Great Depression' of the years 2008-2009, and the deepening of the Euro-zone crisis more and more ideas evolve around the limited capacities of our development. Sustainable development as an approach to social, economic, and institutional realities is flourishing amongst the scholars. The master thesis investigates the paradigm called Green Marketing with its possibilities as well as the criticism, green consumer market, green segmentation, and green marketing strategies. In order to further elaborate on the application of Green Marketing theories, this research paper will focus on the automotive industry. Mobility as it is nowadays, presents an objective to reduce the CO2 emissions, and is already regulated by policies in tact. Electric vehicle as a green product of a very advanced technology needs a creative approach to marketing. The subsequent part of this paper will introduce the specificity of the Tesla Motors electric vehicle and how it influences consumer needs, wants, and perceptions by citing exciting findings within this field. It investigates how can electric vehicle compete with conventional mobility culture to successfully enter new markets.
489

Passenger Flight Experience of Urban Air Mobility

Persson, Daniel January 2019 (has links)
The first part of a study of passenger flight experience of Urban Air Mobility was completed. This first part included the design of different Urban Air Mobility vehicle models, in which the passenger flight experience would be quantitatively measured. A first version of a simulator setup, in which the measurements were performed, was also developed. Three concept vehicle models, a single main rotor, a side-by-side rotor and a quadrotor, were designed in the conceptual design software NDARC. The vehicles were electrically propelled with battery technology based on future technology predictions and were designed for autonomous flight with one passenger. The emissions of the vehicles were analyzed and compared with an existing turboshaft helicopter. The interface between NDARC and the flight dynamics analysis and control system software FlightCODE, which was used to create control systems to the NDARC models,  was developed to fit the vehicle configurations considered. The simulator setup was created with a VR headset, the flight simulation software X-Plane, an external autopilot software and stress sensors. Trial runs with the simulator setup were performed and gave important data for the continued development. Planned upgrades of the simulation station were presented and the continuation of the study was discussed.
490

Evaluating Inductive Electric Road Systems Implementation : A multiple case study in Sweden

Nagarasan, Yuvanesh, Francis Xavier, Kevin Raja January 2020 (has links)
Sustainable transportation solutions are the goal for the future. With the technological shit happening in the transportation market towards electric vehicles, the electric road system (ERS) is a necessary technology required to reach the sustainability goals for the future. While many studies show the role of innovation in a socio-technical landscape, many neglect the diffusion process of the innovation which occurs to create a socio-technical change. The nature of this thesis is an exploratory case study with a qualitative approach. To address the study, a literature review for the diffusion of innovation, its characteristics, multi-level perspective, and technology readiness level (TRL) was presented in order to provide a better understanding and build a foundation for the research. A review of scientific articles regarding the electric road system was performed to provide insights and obtain information on the technology. The data from scientific articles were complemented by interviews from experts regarding electric road systems to obtain an understanding of technology if it was to be implemented in the future in Sweden. The empirics collected were analyzed using the literature framework and conclusions were drawn. Analyzing the data was required to find the factors hindering the technology and if there is a window of opportunity for the technology to exist in the Swedish market. Environmental sustainability has been the driving factor, but the rate of diffusion for the technology will depend on the complexity and the maturity of the technology to function as a whole working system. The study contributes to evaluating the implementation of an inductive electric road system in the Swedish context and if it could be a viable solution in the transportation market. The perspectives of the technology in the Swedish market and the motivation for the solution are discussed. An analytical contribution by evaluating if the technology could exist in the future and insights on the diffusion of the technology into the existing landscape.

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