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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.
1

Qualité de l'énergie dans les alimentations électriques : applications dans les réseaux d'éclairage / Power quality in DC supplied grids : application to lighting networks

Kukacka, Leos 12 February 2018 (has links)
Cette thèse de doctorat porte sur les fluctuations temporelles du flux lumineux des lampes LED, ce phénomène portant le nom de papilottement (flicker). Le papillotement est habituellement considéré comme une perturbation en raison de son impact négatif sur la santé. Pour les systèmes d'éclairage à base de diodes électroluminescentes (LED), sa définition vient d'être formalisée dans la norme IEEE 1789:2015 et a été décrite pour les appareils alimentés en courant alternatif (CA). Ce papillotement alternatif résulte des interactions entre l'impédance du réseau, l'onde de tension, les courants harmoniques et le convertisseur de courant alternatif en courant continu (CA - CC). L'alimentation en courant continu est généralement obtenue via des convertisseurs à découpage. Par conséquent, les mêmes facteurs perturbateurs sont également présents sur les réseaux à courant continu. Cette thèse résume les diférences entre les propriétés caractéristiques du papillotement sous alimentation en CA et en CC. Il a été montré dans la littérature et aussi dans cette thèse qu'avec les LED, le facteur clé qui affecte le papillotement réside dans la conception du driver de LED - une partie indispensable des systèmes d'éclairage à LED. Cette thèse décrit une méthodologie d'évaluation de la sensibilité au papillotement des lampes LED sous alimentation en CC et analyse la façon dont cette sensibilité se modifie lorsque les drivers de LED sont simplifiés et adaptés à des alimentations CC. La thèse présente un ensemble d'expériences de mesure visant à déterminer la réaction typique du papillotement des lampes LED à la fois sous alimentation CA et CC. D'autres expériences ont été efectuées pour révéler l'impact de l'adaptation du driver à l'alimentation CC (en enlevant le pont redresseur à diodes). On constate que certaines lampes présentent une meilleure résistance au papillotement, tandis que d'autres lampes présentent une moindre résistance. Ces expériences sont accompagnées de simulations de drivers pour les lampes LED visant à reproduire et à expliquer les résultats des mesures. La thèse décrit en outre une expérience de mesure visant à montrer la sévérité typique de la variation de tension dans un réseau CC à basse tension couplé au CA domestique et son impact sur le papillotement. On conclut qu'un tel système est suisamment robuste pour filtrer les perturbations provenant du CA, mais une interaction indésirable entre la lampe et l'alimentation peut se produire. / This dissertation thesis is concerned with temporal fluctuations of the luminous flux of LED lamps, a phenomenon referred to as flicker. Flicker is usually regarded as a disturbance due to its negative impact on human health. For lighting systems based on light emitting diodes (LED), its definition has recently been formalised in norm IEEE 1789-2015 and has been documented on devices supplied with AC voltage. AC flicker results from interactions between network impedance, voltage and current harmonics, and the AC to DC converter. DC supplies are generally obtained by switching converters. Consequently, the same perturbing factors are present on DC networks. The thesis summarises the differences between the characteristic properties of flicker under AC and DC supplies. It has been shown in the literature and also in this thesis that the key factor affecting flicker with LEDs is the design of the LED driver-a necessary part of the LED lighting systems. This thesis describes a methodology for the evaluation of the flicker sensitivity of DC supplied LED lamps and analyses how the sensitivity changes when the LED drivers are simplified and accustomed to DC supply. The thesis presents a set of measurement experiments aimed to determine the typical flicker response of LED lamps both under AC and DC supply. Further experiments were performed to reveal the impact of accustomising the driver to the DC supply (removing the diode rectifier). It was found that some lamps show better flicker immunity while other lamps show worse flicker immunity. These experiments are accompanied by LED driver simulations aiming to reproduce and explain the measurement results. The thesis further describes a measurement experiment aimed to show the typical severity of the voltage fluctuation in a low voltage DC network coupled to AC mains and its impact on the flicker. It is concluded that such a system is robust enough to filter out any perturbations coming from the AC supply, but an undesired interaction between the lamp and the supply may occur.
2

Iluminação do estado sólido, economia potencial de energia elétrica para o país

Ferreira, André Rosa January 2014 (has links)
Orientador: Prof. Dr. Jorge Tomioka / Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Engenharia Elétrica, 2014. / Este trabalho apresenta um estudo para a área de iluminação residencial, por meio da utilização da tecnologia de iluminação do estado sólido LED (diodos emissores de luz). Seu objetivo principal é apresentar a economia de energia elétrica para o país trazendo soluções mais eficientes para nossas residências, inclusive podendo ser estendido a outros setores, como indústria e comércio. Isso gerará economia de energia elétrica para o País e favorecerá a preservação do meio ambiente, com a diminuição da emissão de dióxido de carbono (CO2), produzindo impacto imediato na utilização de energia elétrica e prorrogando os grandes investimentos em geração de energia elétrica no Brasil, fazendo reduzir os gastos do dinheiro público. Para a pesquisa, foram levantados vários conceitos aplicados a luminotécnica, para um maior aprofundamento e consolidação dos resultados. Após a fase de pesquisa dos conceitos, foram estudadas as características das diferentes tecnologias de lâmpadas de uso residencial. Foi montada uma bancada para os ensaios das amostras, facilitando a realização das medições, o levantamento de algumas características técnicas, tais como potência da lâmpada, fator de potência, fluxo luminoso e eficiência luminosa. Com a estratificação desses resultados, foi elaborado um estudo de viabilidade econômica entre as três tecnologias de lâmpadas, mostrando o tempo de retorno do investimento. Em seguida, foram realizadas simulações entre as tecnologias de lâmpadas com projeção do consumo de energia elétrica para o ano de 2021. Com a realização deste trabalho cientifico, foi possível chegar a conclusões fundamentais acerca da melhor tecnologia de lâmpada que pode ser aplicada no País no setor residencial. / This work presents a study for the residential lighting through the use of solid-state lighting technology LED ( light emitting diodes ). Its main purpose is to present the economics of electricity for the country bringing more efficient solutions for our homes, and may even be extended to other sectors such as industry and commerce. This will generate electricity savings for the country and encourage the preservation of the environment, with the reduction in the emission of carbon dioxide (CO2), producing immediate impact on electricity usage and extending large investments in power generation in Brazil doing reduce spending of public money . For the research, various concepts applied to illumination, for further development and consolidation of results were collected. After the research phase of the concepts, characteristics of different technologies lamps residential use were studied. A workbench was assembled for testing the samples, facilitating the measurements, raising some technical features, such as the lamp power, power factor, luminous flux and luminous efficiency. Stratification with these results, an economic feasibility study between the three technologies lamps was prepared, showing the time of investment return. Then simulations between technologies of projection lamps with electricity consumption for the year 2021 were performed. With the completion of this scientific work, it was possible to reach basic conclusions about the best lamp technology that can be applied in the Country residential sector.
3

Projeto e implementação de lâmpadas para iluminação de interiores empregando diodos emissores de luz(LEDS) / Design and implementation of interior lighting systems using light emitting diodes(LEDS)

Pinto, Rafael Adaime 31 October 2008 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work presents an efficient lighting system using high intensity light emitting diodes (LEDs). The goal is to develop a compact and low cost electronic circuit to drive and control the current of LEDs disposed in a single enclosure. The proposal aims energy saving, high luminous efficacy and high useful life when replacing traditional lighting systems, as dichroic, incandescent or compact fluorescent lamps by LEDs without any change in electrical system installation. Furthermore, an emergency lighting system integrated into the lamp is proposed, allowing the use of the same equipment in the daily activities, supplied by mains, and under a possible break in the electrical network. To supply the LEDs through the mains with universal input voltage and charge the battery, a Buck converter was employed. To supply the LEDs with a continuous current through the battery, a Boost converter was used. The converters operate at high frequency and control the current through the LEDs independently. The battery can be composed of three rechargeable Ni-MH batteries (1,2 V) or a Li-ion battery (3,6 V). The design attends the Brazilian standard and international standard for emergency lighting systems. To validate the proposed idea, the circuits were designed and implemented. The experimental results are shown with the intention to prove the satisfactory behavior of the lamps. / Este trabalho apresenta um sistema de iluminação eficiente empregando diodos emissores de luz (LEDs) de alta intensidade. O objetivo é desenvolver um circuito eletrônico, compacto e de baixo custo, para acionamento e controle da corrente dos LEDs contidos em um único invólucro. A proposta visa a racionalização no uso da energia elétrica através de uma elevada eficácia luminosa e longa vida útil na substituição dos sistemas de iluminação tradicionais, como lâmpadas dicróicas, incandescentes ou fluorescentes compactas, por LEDs sem qualquer alteração na instalação elétrica. Além disso, é proposto um sistema de iluminação de emergência integrado a esta lâmpada, permitindo a utilização de um único equipamento para iluminação convencional, alimentada pela rede elétrica, e sob uma possível falha no fornecimento de energia. Para alimentar os LEDs, através da rede elétrica, com tensão de entrada universal e ainda carregar a bateria, um conversor Buck é empregado. Para alimentar os LEDs em corrente contínua através da bateria, um conversor Boost é utilizado. Os conversores operam em alta freqüência e controlam a corrente nos LEDs de forma independente. A bateria pode ser composta por três pilhas recarregáveis de Ni-MH (1,2 V) ou por uma bateria de Li-Ion (3,6 V). O projeto atende às exigências da norma brasileira (NBR 10898) e da norma internacional (IEEE Std 446-1995) para sistemas de iluminação de emergência. Para analisar a idéia proposta, os circuitos são projetados e implementados. Os resultados experimentais são apresentados de forma a comprovar o comportamento satisfatório das lâmpadas.

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