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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

Single phase bidirectional DAB DC-DC converter based on three state switching cell / Conversor CC-CC bidirecional DAB monofÃsico baseado na cÃlula de comutaÃÃo de trÃs estados

Luan Carlos dos Santos Mazza 15 December 2014 (has links)
This work presented is DC-DC isolated ZVS Bidirectional Dual Active Bridge (DAB) single phase converter, based three-state switching cell is presented. The proposal is to apply it in photovoltaic systems with battery bank into smart networks. Basically the drive control is the duty cycle (D) of the switches and the Phase Shift (φ) of the fundamental tensions between the bridges. The gyrator modeling of the converter is presented, highlighting its natural operating characteristic as gyrator. Shows the qualitative and quantitative analysis of the converter, realizing the full study of the stages of operation of the topology and checking all sixteen regions of operation. To obtain the regions of soft-switching, the fundamental model is applied. The design procedure of the converter is presented, and the results of simulations. A 2kW prototype was developed, aimed at obtaining experimental results validate the theoretical analysis / Neste trabalho à apresentado o conversor CC-CC ZVS isolado bidirecional Dual Active Bridge (DAB) monofÃsico, baseado na cÃlula de comutaÃÃo de trÃs estados. A proposta à aplicÃ-lo em sistemas fotovoltaicos com banco de baterias em redes inteligentes. Basicamente o controle do conversor consiste na razÃo cÃclica (D) dos interruptores e o Phase Shift (φ) entre as componentes fundamentais das tensÃes entre as pontes. A modelagem por gyrator do conversor à apresentada, destacando-se sua caracterÃstica natural de funcionamento como gyrator. Mostra-se a anÃlise qualitativa e quantitativa do conversor, realizando o estudo completo das etapas de operaÃÃo da topologia e verificando todas as dezesseis regiÃes de operaÃÃo. Para obtenÃÃo das regiÃes de comutaÃÃo suave, à aplicado o modelo fundamental. O procedimento de projeto do conversor à apresentado, alÃm dos resultados de simulaÃÃes. Um protÃtipo de 2 kW foi desenvolvido, visando a obtenÃÃo dos resultados experimentais e validando a anÃlise teÃrica.
2

Optimisation d’une structure de conversion DC/DC réversible pour application aéronautique de forte puissance / Optimization of a High Power Reversible DC/DC Converter for Aircraft Application

Blanc, Maximin 26 October 2017 (has links)
Le véhicule aérien a connu de nombreuses révolutions durant les dernières décennies afin d’être plus économe en énergie et plus respectueux de l’environnement. Dans cet objectif, l’électricité est apparue comme le vecteur énergétique le plus adapté associé aux sources conventionnelles d’énergie. C’est dans ce contexte que nos recherches se sont portées sur ce mode de transport qui va voir des bouleversements structurels importants et de plus en plus d’équipements électriques installés à bord. Ce travail de recherche s’intéresse à une brique de conversion DC/DC nécessaire au transfert d’énergie entre les bus HVDC et LVDC présents sur les avions actuels, pour cela nous avons étudié la structure et le contrôle de la topologie Dual Active Bridge qui apparaît comme le meilleur candidat pour atteindre les objectifs techniques, de rendement et compacité. Un dimensionnement ainsi que des résultats expérimentaux sont présentés pour valider nos choix avec un démonstrateur de 3,75kW. Des pistes de réflexions sont enfin proposées pour poursuivre et étendre certaine assertions vers une structure tri-ports pour l’interfaçage de multiples réseaux et moyen de stockage. L’originalité de ses travaux réside dans la volonté de concevoir un produit industrialisable dans le domaine de l’aéronautique en favorisant plusieurs ruptures technologiques jusqu’alors rédhibitoire chez les avionneurs. / Avionics is intended to become more and more efficient in terms of energy saving thanks to increased efficiency of embedded system. Today, electricity is presented as the best energy vector compared to hydraulic or pneumatic. This is why current researches aim to focus on power electronic converters in order to meet the future electrical power demand in aircraft networks. This research project presents a DC/DC dual active bridge converter which is expected as the best candidate to meet the complex requirements of an aircraft environment, especially the high voltage dynamics. This persuaded us to study the structure and modulations which are explained and brought face to face with a 3,75kW demonstrator in order to validate the theoretical assumptions. Some food for thought is proposed to extend this work toward a three-port converter to interface multiple network as well as storage systems. The originality of this work is to build a new kind of active conversion system promoting break through technologies to prove it suits to aircraft specifications.
3

"Inversor multinível NPC monofásico com comutação suave e grampeamento ativo" / "Single phase ZVS NPC multilevel inverter with active clamping"

Barreto, Eduardo Maldaun 08 December 2011 (has links)
Made available in DSpace on 2016-12-12T17:38:31Z (GMT). No. of bitstreams: 1 EDUARDO MALDAUN BARRETO.pdf: 3234972 bytes, checksum: 1d2d2b79d8a4946c00677b6193158089 (MD5) Previous issue date: 2011-12-08 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work present a study of a three level NPC (Neutral Point Clamped), with ZVS (Zero Voltage Switching) and PWM (Pulse Width Modulation) control strategy, using a FPGA (Field Programmable Gate Array) for digital control and switches activation. First, a theoretical study is done, where the main waveforms and operation stages are presented. After, a quantitative study is done in order to implement the NPC inverter. Based on the calculations, the mathematical models for each inverter section are extracted to implement the digital control. The project data is then compiled and simulated on Orcad Pspice and Simulink software. Finally, an 1.5 kW, 800 V input voltage, 127 V or 220 V output voltage, and 200 kHz switching frequency is implemented and the experimental results are compared with theoretical and simulated results / Este trabalho apresenta o estudo de um inversor NPC (Neutral Point Clamped) a três níveis com comutação suave ZVS (Zero Voltage Switching) e controle PWM (Pulse Width Modulation), fazendo o uso de uma lógica programável do tipo FPGA (Field Programmable Gate Array) para controle e acionamento das chaves. Inicialmente é feito um estudo qualitativo do inversor, onde as principais formas de onda e etapas de operação são apresentadas, a seguir são estudados os aspectos quantitativos para, desta forma, efetuar o projeto do inversor. Com o inversor definido, todos os modelos matemáticos de todos os circuitos necessários para se realizar o controle digital do inversor são apresentados, assim como o projeto de um controlador digital. Utilizando os dados de projeto do inversor NPC ZVS PWM e controle, os resultados de simulações feitas nos programas Orcad Pspice e Simulink são obtidos. Por fim, um protótipo de 1,5 kW, 800 V de tensão de entrada, 127 V ou 220 V de tensão de saída e 200 kHz de frequência de comutação é montado e os resultados experimentais são avaliados e comparados com os previamente obtidos numericamente e por simulação.

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