This work specifies the synthesis and the characterization of amorphous powders belonging to the Y2O3 - Al2O3 - B2O3 system. The main objective of this work was to develop amorphous powders near the YAl3(BO3)4 composition without any rare earth as doping for the development of a new family of phosphors for solid state lighting systems excited by near ultra-violet light. The sol-gel and polymeric precursor methods were applied in order to produce these powders. After these syntheses we optimized several parameters such as thermal treatments: two different routes were tested: direct calcination and pyrolytic decomposition followed by calcination. The temperature, annealing time, heating rate and the effects of impurities on the photoluminescence (PL) were studied. A comparison between these two synthesis methods was done. The powder samples were characterized by thermal analysis technique, X-ray diffraction, photoluminescence and infra-red spectroscopies, transmission and scanning electron microscopy, elemental analysis and electron probe microanalyses, nuclear magnetic resonance, cathodoluminescence, electronic paramagnetic resonance. From the thermal analyzes, it was observed that the powder prepared by polymeric precursor method shows a glass transition temperature (Tg) around 740 °C and crystallization temperatures (Tx) at 815, 850 and 900 °C. Amorphous powder showing high photoluminescence emission (between 400 and 750 nm) and quantum yields higher than 90% at 365 nm excitation, without any phase segregation were obtained when the samples are annealed at temperatures at around Tg, above this temperatures the powder start to crystallize decreasing their PL properties. Other compositions were studied by increasing the relative amounts of Y2O3, Al2O3 and B2O3, by removing the yttrium, addition of SiO2. Finally, the first measurements of color coordinates and the preliminary tests on the thermal and photo stability have been done. / Ce travail de these porte sur la synthèse et la caractérization de poudres amorphes en appartenant système Y2O3 - Al2O3 - B2O3. L'objectif principal du travail a été de préparer des poudres amorphes dont la composition est proche de YAl3(BO3)4 sans terre rare en vue la réalisation de phosphores pour des dispositif d'éclairage solide à base de LED emmetant dans le proche UV. Pour la synthèse des poudres les methodes sol-gel et celles des precurseurs polymériques ont été utilisées. Nous avons ensuite optimizé les paramètres thermiques, en utilisant deux stratégies: la calcination directe et la pyrolyse suivrie d'une seconde étape de calcination. La température, le temps de recuit, vitesse de chauffage et les effect des impurities sur la photoluminescence ont été étudié. Les échantillons en poudre ont été caractérisés par les techniques d'analyse thermiques, diffraction des rayons X, la spectroscopie de photoluminescence et la spectroscopie infra-rouge, microscopies électronique à balayage et en transmission, les méthodes des analyses élémentaire et microsonde électronique, la résonance magnétique nucléaire, cathodoluminescence et le résonance paramagnétique électronique. Par l'analyse thermique, on a observé que la poudre préparée par la méthode de précurseur polymère a une température de transition vitreuse (Tg) autour de 740 ° C et des températures de cristallisation (Tx) à 815, 850 et 900 ° C. Les poudres amorphes presentent de larges bandes d'émission de photoluminescence (entre 400 et 750 nm) avec des rendements quantiques supérieurs à 90% pour une excitation de 365 nm. De plus, les poudres microscopiques obtenu sont chimiquement homogene avec des composition très proche de celle initialmente visée YAl3(BO3)4 lorsque les échantillons sont recuits à des températures voisine du Tg. Au-dessus de cette température, la poudre commence à se cristalliser conduisant à réduction de l'intensité de PL. D'autres compositions ont été étudiées en augmentant la quantité relative de Y2O3, Al2O3 et B2O3, en éliminant complètement l'yttrium, ou en ajutant SiO2. Finalement, les premiers mesures de coordonnées de couleur et les essais préliminaires sur la stabilité thermique et photométrique sont très prometeur. En effet, outres les rendemente specifiques de luminescence très elevés ces luminophores émitent de lumiére très chaudes.

This work consists of the study, design and implementation of DC-DC converters, used in lighting systems based on light emitting diodes (LEDs). Can be powered by an universal AC voltage source or battery, and the current in the LEDs is controlled digitally. The main objective is to present a proposal of new step-up/down converters topologies with full conversion much higher than that of conventional converters. So, is initially presented an overview of solid-state lighting (SSL). Following is presented the study on the dynamic behavior of converters based on modeling by the method of varying state-space average, ending with the design of a digital PI controller. This work resulted in the application for a patent PI-0801425-6 filed with the INPI, which presents a new family of converters with full conversion extremely wide, called cubic converters. / O presente trabalho consiste do estudo, projeto e implementação de conversores CCCC, aplicados em sistemas de iluminação de estado sólido baseado em diodos emissores de luz (LEDs). Podem ser alimentados por uma fonte de tensão alternada universal ou por uma bateria sendo que a corrente nos LEDs é controlada digitalmente. O objetivo principal é apresentar uma proposta de novas topologias de conversores abaixadores/elevadores com faixa de conversão muito maior que a dos conversores convencionais. Portanto, inicialmente é apresentada uma visão geral sobre iluminação de estado sólido (SSL). Na sequência, é apresentado o estudo sobre o comportamento dinâmico dos conversores baseado na modelagem através do método de variáveis de espaço de estados médio, finalizando com o dimensionamento de um controlador PI digital. Este trabalho resultou no pedido de patente de invenção PI-0801425-6 depositado junto ao INPI, o qual apresenta uma nova família de conversores com faixa de conversão extremamente larga, denominados de conversores cúbicos. / Doutor em Ciências

Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-06-03T12:39:45Z No. of bitstreams: 1 claudiorobertobarbosasimoesrodrigues.pdf: 5762936 bytes, checksum: 8a7ae73391a9d56af3c18605a924763d (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-07-02T13:21:41Z (GMT) No. of bitstreams: 1 claudiorobertobarbosasimoesrodrigues.pdf: 5762936 bytes, checksum: 8a7ae73391a9d56af3c18605a924763d (MD5) / Made available in DSpace on 2016-07-02T13:21:41Z (GMT). No. of bitstreams: 1 claudiorobertobarbosasimoesrodrigues.pdf: 5762936 bytes, checksum: 8a7ae73391a9d56af3c18605a924763d (MD5) Previous issue date: 2012-12-17 / No intuito de aportar contribuições ao uso de diodos emissores de luz (ou LEDs, do inglês Light Emmiting Diodes) em sistemas de iluminação pública, cobrindo lacunas existentes no cenário nacional, este trabalho traz uma ampla análise sobre este tema. São apresentados conceitos básicos da fotometria clássica e um estudo sobre adaptações da fotometria para baixos níveis de luminância, que é a condição observada nas vias públicas durante o período noturno. Propõe-se a utilização de métricas escotópicas em sistemas de iluminação pública, uma vez que estas melhor representam a real sensação visual (se comparadas às métricas clássicas – fotópicas) nas condições de iluminamento típicas observadas nestes sistemas. Aspectos gerais da iluminação pública e um histórico da evolução do sistema nacional são brevemente apresentados bem como uma discussão sobre a situação atual deste sistema e das tecnologias utilizadas. O trabalho traz também um estudo sobre características ópticas, elétricas e mecânicas dos LEDs e uma análise dos diferentes tipos de LEDs brancos mais utilizados (HB – High Brightness – e HP – High Power – LEDs). Algumas normas e recomendações aplicáveis à utilização de LEDs em iluminação pública são analisadas e discutidas, com o intuito de se investigar lacunas ainda não cobertas pela normatização existente. Análises de resultados de ensaios de laboratório e de campo, inéditos no país, realizados com alguns modelos de luminárias LED para iluminação pública disponíveis no mercado, são também apresentadas. Um estudo sobre acionamento de LEDs é realizado, abordando técnicas de equalização de corrente entre arranjos série de LEDs associados em paralelo e diferentes tipos de circuitos de acionamento para LEDs. São propostas, analisadas e implementadas uma estrutura inédita de baixo custo para a equalização de corrente e um circuito para o acionamento de LEDs baseado na integração de dois conversores cc cc não isolados. A topologia de dois estágios proposta é composta por um conversor boost no primeiro estágio, utilizado para a correção do fator de potência e por um conversor buck no segundo estágio, utilizado para o controle da corrente nos LEDs. Por fim, o acompanhamento da implantação e do desempenho, ao longo de dez meses, do projeto piloto de iluminação pública empregando LEDs instalado no anel viário da Faculdade de Engenharia da UFJF é apresentado. / In order to present contributions to the use of light emitting diodes (LEDs) in public lighting systems, covering gaps on the national scenario, this work encompasses abroad analysis related to this issue. Basic concepts of classical photometry are presented and so a study of photometry’s adaptations for low luminance levels. It is proposed the use of scotopic metrics for street lighting systems, since they can better represent the actual visual sensation (when compared to the classical one – photopic metrics) on its typical nighty conditions. General aspects of street lighting and the history of the national’s public lighting system are briefly presented as well as a discussion about the current situation of the Brazilian system and technologies adopted. The work also brings a study of mechanical, electrical and optical characteristics of LEDs and an analysis of the two different types of commonly used white LEDs (HB – High Brightness – and HP – High Power - LEDs). Some standards and recommendations related to the use of LEDs in street lighting are analyzed and criticized, with the aim of show some gaps not yet covered by the existent standards. An unprecedented analysis regarding laboratory and field test benchmarking, taken for some luminaires available in commerce, is also presented. A study of LED driving is presented, covering equalization techniques for parallel LEDs strings and different types of LED driving circuits. It was proposed, analyzed and implemented a novel and low cost structure for current equalization and an LED driver, based on the integration of two non-isolated dc dc converters. This proposed two stages topology is composed by a boost converter, on the first stage, employed to the power factor correction and a buck converter, on the second stage, to control the LED’s current. Finally, the process of monitoring the installation and the performance, during ten months, of the LEDs public lighting pilot project, on the roadway belt of Engineering Faculty of UFJF is presented.

Submitted by isabela.moljf@hotmail.com (isabela.moljf@hotmail.com) on 2017-07-03T11:17:42Z No. of bitstreams: 1 mateusfreitasbraga.pdf: 1732565 bytes, checksum: f8ebb1cc4fe4d9ecbd9cc50ba3eb3f2a (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-08-07T21:17:21Z (GMT) No. of bitstreams: 1 mateusfreitasbraga.pdf: 1732565 bytes, checksum: f8ebb1cc4fe4d9ecbd9cc50ba3eb3f2a (MD5) / Made available in DSpace on 2017-08-07T21:17:21Z (GMT). No. of bitstreams: 1 mateusfreitasbraga.pdf: 1732565 bytes, checksum: f8ebb1cc4fe4d9ecbd9cc50ba3eb3f2a (MD5) Previous issue date: 2017-03-20 / Cresce a cada dia o n úmero de cargas não lineares conectadas aos diversos sistemas el étricos, seja em ní vel de transmissão ou distribui ção. Como consequência desse crescimento, e possí vel encontrar casos de consumidores enfrentando problemas relacionados a desarmes de disjuntores e sobreaquecimento de condutores, entre outros efeitos indesejados. Tomando um desses casos como base para este estudo, esta disserta ção tem o objetivo de avaliar e propor uma solu ção para uma rede monof asica real, que possivelmente e comum a outros consumidores. A carga monof ásica composta por lumin árias a LED (t picas cargas não lineares) e cargas indutivas se apresenta aos terminais da fonte com um comportamento de elevado conte udo harmônico (THD) de corrente e baixo fator de potência. Essa condi ção adversa pode ser mitigada de diversas maneiras, como por exemplo pela a ção de um fi ltro passivo,fi ltro ativo ou ainda fi ltro h brido (o qual e composto por uma combina ção dos dois primeiros). Ser a proposto nesta disserta ção uma metodologia de projeto relacionada a aplica ção de um fi ltro hi brido monof ásico visando corrigir o fator de potência e reduzir o conte udo harmônico de corrente presente na fonte, tomando como base as caracterí sticas do sistema avaliado em uma ind ústria gr áfi ca t ípica. Serão investigadas algumas con gura ções de filtros com o objetivo de mitigar problemas de Qualidade de Energia El étrica. Como consequência, ser a desenvolvida a an álise matem atica da topologia adotada e o projeto do controlador, baseado em um controlador proporcional-ressonante e na Teoria p-q Monof asica. A veri ca ção da solu ção proposta e sustentada pelos resultados de simula ção obtidos via software PSIM. / The amount of non-linear loads connected to the various electrical systems grows on a daily basis, regardless those loads are tied to a transmission or distribution bar. As a consequence of this growth, it is possible to nd cases of consumers facing problems such as tripping of breakers and cables overheating, among other undesired e ects. Taking one of these cases as the focus of this study, this dissertation aims to evaluate and propose a solution to a real single-phase system, which could be considered similar to other consumers. The single-phase load composed of LED luminaires (typical non-linear load) and inductive loads presents high THD and low power factor behavior at source terminals. This condition can be mitigated by using some well-known techniques, such as passive lters, active lters or hybrid lters, (which are composed by the combination of the former two). This Master document Thesis proposes a design methodology of a single-phase hybrid lter aiming power factor correction and reduction of the harmonic content of the current delivered by the AC power supply when feeding a typical printing factory. It will be reviewed and discussed some possible lter con gurations aimed to solve the case under evaluation. It is also included the mathematical analysis of the proposed topology, along with the design of the control system of the inverter. The Single-Phase p-q Theory is reviewed in order to design the control. The closed-loop control is desinged by a proportional-resonant compensator. Simulation results, by employing the PSIM software, are provided aiming to validate the solution proposed.

Phases organiques luminescentes qui sont incorporés dans une matrice inorganique conductrice est proposé dans cette étude pour la couche active d'une diode émettant de la lumière hybride. Dans ce composite, le colorant organique joue le rôle de site de recombinaison radiative de porteurs de charge qui sont injectées dans la matrice de transport ambipolaire inorganique. Comme l'un des combinaisons de matériaux de candidat, bicouche et des films minces composites de ZnSe et un complexe d'iridium rouge (Ir(BPA)) émetteur de lumière organique ont été préparé in situ par UHV technique d'évaporation thermique. Les alignements de bande d'énergie mesurée par spectroscopie de photoélectrons (PES) pour le ZnSe/Ir(BPA)et deux couches de ZnSe+Ir(BPA) révèlent que le composite HOMO et LUMO du colorant organique sont positionnées dans la largeur de bande interdite de ZnSe. Cette gamme offre les forces motrices énergiques nécessaires pour les transferts d'électrons et de trous de ZnSe à Ir(BPA). Par l'interprétation des données du PES,la composition chimique des interfaces ont également été déterminés. Le ZnSe/Ir(BPA) interface est réactive, même si elle est d'une pureté de matériaux de haute.Pendant ce temps, l'Ir (BPA)/ZnSe interface ne présente pas la pureté matériel. Ceci est représenté à la nature de ZnSe évaporation comme Zn particuliers et des fluxSE2, associée à des interactions chimiques avec le Ir(BPA) substrat. L'interface est,de ce fait, composé d'une multitude de phases, les phases de Se0, ZnSe rares, réduit Se et oxydé molécules de colorant, et de Zn qui sont intercalées atomes dans leIr(BPA) substrat. PES des composites ZnSe+Ir(BPA) révèle des tendances similaires à l'Ir(BPA)/ZnSe interface. A des émissions de lumière rouge surfaciques et intermittents fanées ont été observés à partir de dispositifs qui incorporent couches alternées séquences de ZnSe et Ir(BPA) pour la couche active. / Luminescent organic phases that are embedded in a conductive inorganicmatrix is proposed in this study for the active layer of a hybrid light-emitting diode. Inthis composite, the organic dye acts as the radiative recombination site for chargecarriers that are injected into the inorganic ambipolar transporting matrix. As one ofthe candidate material combinations, bilayer and composite thin films of ZnSe and ared iridium complex (Ir(BPA)) organic light emitter were prepared in situ via UHVthermal evaporation technique. The energy band alignments measured byphotoelectron spectroscopy (PES) for the ZnSe/Ir(BPA) bilayer and ZnSe+Ir(BPA)composite reveal that the HOMO and LUMO of the organic dye are positioned in theZnSe bandgap. This lineup provides the required energetic driving forces for electronand hole transfers from ZnSe to Ir(BPA). By interpreting PES data, the chemicalcomposition of the interfaces were also determined. The ZnSe/Ir(BPA) interface isreactive even though it is of high material purity. Meanwhile, the Ir(BPA)/ZnSeinterface does not exhibit material purity. This is accounted to the nature of ZnSeevaporation as individual Zn and Se2 fluxes, coupled with chemical interactions withthe Ir(BPA) substrate. The interface is, thereby, composed of an abundance of Se0phases, sparse ZnSe phases, reduced Se and oxidized dye molecules, and Znatoms that are intercalated into the Ir(BPA) substrate. PES of the ZnSe+Ir(BPA)composites reveals similar trends to the Ir(BPA)/ZnSe interface. A faded areal andintermittent red light emissions were observed from devices that incorporatedalternating layer sequences of ZnSe and Ir(BPA) for the active layer.