CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / This work presents a study and design of an electronic power converter topology for on-board application in a battery charger for plug-in electric vehicles. The proposed topology is based on AC-DC converter Buck+Boost, which one is very attractive for this application due to its buck and boost characteristics in a single-stage power processing. Furthermore, this topology presents reduced weight and volume, since there is no transformer and only few components are presented in its structure. A theoretical study is performed through of qualitative and quantitative analysis, besides it is investigated the switching process and losses in the converter components. It is also performed a design example of a battery charger with rated output power of 1 kW, input voltage 220 Vac RMS and output voltage of 162 Vdc, corresponding to 12 batteries connected in series. A prototype for the indicated specifications was constructed in laboratory and tested experimentally. The simulation and experimental results obtained are used to validate the theoretical analysis and design. For rated load, it was obtained an efficiency of 96.5% and a power factor of 0.992, thus showing the effectiveness of the proposed converter. / Este trabalho apresenta o estudo e desenvolvimento de uma topologia de conversor eletrÃnico de potÃncia para a aplicaÃÃo embarcada em um carregador de baterias para veÃculos elÃtricos recarregÃveis atravÃs da rede elÃtrica. A topologia escolhida à baseada no conversor CA-CC Buck+Boost, onde a mesma torna-se bastante atrativa para este tipo de aplicaÃÃo por apresentar as caracterÃsticas elevadora e abaixadora de tensÃo em um Ãnico estÃgio de processamento de energia. AlÃm disso, esta topologia apresenta reduzido volume e peso, devido ao fato de nÃo apresentar transformador e possuir poucos componentes em sua estrutura. Um estudo teÃrico à realizado atravÃs das anÃlises qualitativa e quantitativa, alÃm das anÃlises do processo de comutaÃÃo e das perdas nos componentes do conversor. Neste trabalho à realizado um exemplo de projeto do carregador de baterias para aplicaÃÃo em veÃculos elÃtricos de 1 kW de potÃncia de saÃda, tensÃo de entrada eficaz de 220 Vca e tensÃo de saÃda de 162 Vcc, correspondente a 12 baterias conectadas em sÃrie. Um protÃtipo com as especificaÃÃes indicadas foi construÃdo e testado experimentalmente em laboratÃrio. Os resultados de simulaÃÃo e experimentais obtidos validaram a anÃlise teÃrica e o projeto realizado. Para carga nominal, foi obtido rendimento de 96,5% e fator de potÃncia de 0,992, comprovando assim o funcionamento da topologia utilizada.

FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / This work deals with the theoretical analysis, design methodology and laboratory implementation of a 3kVA on-line mode Uninterruptible Power Supply (UPS) composed by a multilevel inverter based on a transformer with multiple secondaries and an active power factor correction input stage composed by a diode rectifier in series with a boost converter.The main motivation for this study is to assess the benefits of multilevel inverters in low power (<10kVA) applications. A 3kVA Uninterruptible Power Supply (UPS) with output and input voltage of 220V and 60Hz, has been implemented. Simulation and experimental results for a single phase prototype are conducted to validate the proposed idea. The utilization of low frequency operation inverters promotes low EMI, lower switches stresses, very low commutation losses and consequently higher efficiency. The multilevel converter here used isolates the load from the grid due to the multi-windings transformer intrinsic to the topology. The on-line mode of the UPS (no battery mode) has been implemented. Simulation and experimental results for a single-phase prototype are presented to validate the proposed converter. The UPS presented an efficiency of 90% / Este trabalho apresenta a anÃlise teÃrica, metodologia de projeto e implementaÃÃo do modo rede de um sistema ininterrupto de energia (UPS) na configuraÃÃo on-line, utilizando um inversor multinÃvel e um prÃ-regulador com correÃÃo de fator de potÃncia. O inversor baseia-se num transformador que opera em baixa freqÃÃncia com mÃltiplos secundÃrios isolados, em que a tensÃo multinÃvel na saÃda à formada atravÃs da combinaÃÃo dos enrolamentos secundÃrios do transformador por chaves de potÃncia estÃticas operando em baixa freqÃÃncia. O prÃ-regulador à composto por uma ponte completa de diodos em sÃrie com um conversor boost. A motivaÃÃo para este estudo consiste em avaliar os benefÃcios da utilizaÃÃo de inversores multinÃveis em baixas potÃncias (<10kVA) em UPS, com Ãnfase nos rendimentos das topologias. A utilizaÃÃo do inversor multinÃvel operando em baixa freqÃÃncia garante menores Ãndices de EMI, menores esforÃos de tensÃo e corrente nos semicondutores da estrutura, desprezÃveis perdas por comutaÃÃo e consequentemente maior rendimento. A estrutura utilizada possui ainda a caracterÃstica de garantir isolamento galvÃnico da rede elÃtrica com a carga atravÃs da utilizaÃÃo do transformador intrÃnseco desta topologia. O prÃregulador possui uma topologia que garante facilidade de implementaÃÃo e alto rendimento. O modo rede de um sistema ininterrupto de energia de 3kVA com tensÃo de entrada e saÃda de 220V e 60Hz, foi implementado. As simulaÃÃes e os resultados experimentais para um protÃtipo monofÃsico sÃo apresentados para a validaÃÃo da estrutura. O rendimento mÃximo obtido para o protÃtipo foi de 90%.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / This work presents the study and implementation of an ac-dc &#262;uk converter based on the three state switching cells applied in charger stations for electric vehicles. This converter has, as main characteristics, reduction of conducting power losses in the semiconductors, a single stage topology and current source behavior for both input and output terminals. As drawbacks, the topology presents: the voltage across the semiconductors is equal to the sum of the input and the output voltages, and a difference between the current values through the semiconductors caused by an inappropriate layout of the power prototypes or by a lack of symmetry between the control signals. The analysis of the converter is made through the qualitative and quantitative studies, beyond the analysis of the semiconductor losses which are presented as well. The current and voltage of the battery are controlled by the average current mode technique, which consist in a fast current control loop if compared with the terminals battery voltage control loop. The topology is design for 1 kW output power, 220 V in input voltage and 162 V in the output terminals (12 batteries in series connection). Experimental results for resistive load, as well batteries, are shown in order to verify the functionalities of the topology and its characteristics. / Este trabalho apresenta o estudo e desenvolvimento de um conversor ca-cc &#262;uk baseado na cÃlula de comutaÃÃo trÃs estados para aplicaÃÃo em carregadores de baterias para veÃculos elÃtricos. As principais caracterÃsticas deste conversor sÃo: a reduÃÃo das perdas por conduÃÃo nos interruptores controlados, um Ãnico estÃgio de processamento de potÃncia e caracterÃstica de fonte de corrente na entrada e na saÃda. Como inconvenientes a topologia apresenta: a tensÃo sobre os semicondutores igual à soma das tensÃes de entrada e saÃda e o desequilÃbrio de corrente atravÃs dos componentes quando hà assimetria no layout da placa de potÃncia ou nos sinais de comando dos interruptores. Um estudo teÃrico à realizado atravÃs das anÃlises qualitativa e quantitativa, alÃm das anÃlises do processo de comutaÃÃo e das perdas nos componentes do conversor. Para controlar o fluxo de potÃncia da rede elÃtrica para as baterias à utilizada a estratÃgia de controle modo corrente mÃdia, sendo que, a mesma apresenta uma malha de corrente rÃpida que monitora a corrente de entrada e uma malha de tensÃo lenta que supervisiona a tensÃo sobre os terminais da bateria. Neste trabalho à realizado o projeto do carregador de baterias para aplicaÃÃo em veÃculos elÃtricos com 1 kW de potÃncia, tensÃo de entrada eficaz de 220 V e tensÃo de saÃda de 162 V, correspondente a 12 baterias conectadas em sÃrie. Um protÃtipo com as especificaÃÃes indicadas foi construÃdo e testado experimentalmente em laboratÃrio e os resultados de simulaÃÃo e experimentais obtidos sÃo utilizados para validar a anÃlise teÃrica e o projeto realizado. Foram realizados testes com carga puramente resistiva e em seguida com um banco de baterias, que comprovaram o funcionamento da topologia.

Orientador: Edson Bim / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação / Made available in DSpace on 2018-08-19T12:13:39Z (GMT). No. of bitstreams: 1 Kanekiyo_MarcoTadashi_M.pdf: 2199502 bytes, checksum: 0f0e07fdf7f52de94709720bdddef861 (MD5) Previous issue date: 2011 / Resumo: O objetivo deste trabalho é o de implementar o controle de velocidade e de potência reativa de um motor de indução duplamente alimentado com orientação de fluxo de estator, mediante o ajuste das componentes de eixo direto e em quadratura das correntes de rotor, sendo o estator conectado à rede elétrica trifásica. Para isto foram utilizados quatro controladores PI: dois deles têm a função de gerar as referências dessas correntes a partir dos erros da potência reativa e da velocidade, e os outros dois, a de gerar as referências das tensões de eixo direto e em quadratura, a partir dos erros dessas mesmas correntes. Resultados experimentais do motor operando com fator de potência adiantado, unitário e atrasado são apresentados para validar a proposta. O sistema de controle, implementado por um DSP TMS320F2812, é responsável pela leitura das tensões e correntes de estator, da velocidade e da estimação da posição do eixo, pelas transformações de variáveis, pela implementação dos controladores PI, pela determinação da magnitude e posição do fluxo de estator e pela implementação da modulação do vetor espacial / Abstract: The purpose of this work is to present the implementation of the speed control and reactive power of a doubly fed induction motor with stator flux orientation, by adjusting of the direct and quadrature-axis rotor current components, being the stator fed by a triphasic network. With this aim, four PI controllers are used: two of them have the function of generating the direct and quadrature references of the rotor current from the direct and quadrature rotor voltage errors and the others two, of generating the direct and quadrature references of the rotor voltage from the direct and quadrature rotor current errors. Experimental results of the motor operating with leading, lagging and unity power factor are presented to validate the proposal. The control algorithm is implemented with a digital signal processor and it has the following functions: lecture of the voltages and currents of rotor, lecture of speed and estimation of rotor position, transformations of variables, implementation of the PI controllers, calculus of magnitude and position of stator flux and space vector modulation / Mestrado / Energia Eletrica / Mestre em Engenharia Elétrica

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work presents the development of a methodology for design of inductor in singlephase PFC boost converters operating in CCM mode in agreement with international standards IEC 61000-3-2 and CISPR 22. Such converters are used in front-end modules of information technology equipment. This methodology is based on the investigation of the relationship among magnetic volume; switching frequency and input current ripple of the converter, presented in previous work and extended to allow the optimization of inductors with three magnetic materials: Kool Mμ, Molypermalloy and High-Flux. An analysis of some constructive characteristics of the inductors is performed, such as, magnetic materials and most appropriate type of winding, taking into account factors that can determine the lowest volume of the inductor, such as winding and magnetic losses, the flux density, and conducted electromagnetic interference (EMI). In construction of the inductors, it is discussed the use of single-layer winding, presenting their main haracteristics, advantages when seeking the reduction of conducted EMI, and considering the disadvantage of increasing of volume that this type winding may cause. An algorithm for this methodology is developed, that uses models able to estimate the differential mode conducted EMI for frequencies up to 30 MHz, as well the temperature rise of boost inductor by simulating the input current of the converter, considering soft saturation characteristics of magnetic materials and the use of commercial cores. Additionally, it is performed an experimental validation of the developed algorithm by construction of prototypes that uses three selected materials and operate at three different points of operation. / Este trabalho apresenta o desenvolvimento de uma metodologia de projeto do indutor em conversores boost PFC CCM monofásicos de acordo com as normas internacionais IEC 61000-3-2 e CISPR 22. Tais conversores são utilizados como estágio de entrada em fontes de equipamentos da tecnologia da informação. A metodologia é baseada na investigação da dependência existente entre o volume dos elementos magnéticos com a freqüência de comutação e a ondulação da corrente de entrada nestes conversores. O trabalho dá continuidade a trabalhos anteriores, ampliando a análise para a otimização de indutores de três materiais magnéticos: Kool Mμ, Molypermalloy e High-Flux. É realizada uma análise de algumas características construtivas destes indutores, entre elas, os materiais magnéticos mais apropriados e o tipo de enrolamento utilizado levando-se em consideração fatores que permitem a redução do volume do indutor, como as perdas magnéticas e nos enrolamentos, a densidade de fluxo magnético e a interferência eletromagnética (EMI) conduzida. Na implementação dos indutores, é discutida a utilização de enrolamentos de única camada, apresentando suas principais características, as vantagens de sua utilização quando se busca a redução da EMI conduzida, e considerando-se a desvantagem do aumento de volume do indutor que este tipo de enrolamento pode causar. Um algoritmo é desenvolvido para esta metodologia, no qual são utilizados modelos capazes de estimar a EMI conduzida DM para freqüências de até 30 MHz, assim como a elevação da temperatura do indutor, por meio de uma simulação da corrente de entrada do conversor que considera os efeitos da saturação suave dos materiais magnéticos e a utilização de núcleos com dimensões comerciais. É também realizada a validação experimental deste algoritmo, por meio da construção de protótipos que utilizam indutores dos três materiais escolhidos e operam em três pontos de operação distintos.

AC-DC converters find application in every day life as a front-end to DC-DC and DC-AC converters. Active three-phase converters shape the three-phase input current to be sinusoidal and to be in-phase with the input voltage, as well as to provide a steady DC output voltage. This thesis investigates various active three-phase rectifier and control topologies and identifies a rectifier and control topology most suitable for use in converting a variable voltage variable frequency generator output to a DC voltage. In this dissertation, design relations are derived for determining the plant transfer response (for the suitable topology/controller), design equations are derived for designing/choosing the filter components, and guidelines are derived that will assist in choosing the right semi-conductor components and to give an estimation of expected system efficiency. The dissertation investigates the implementation of both analogue and digital control and provides implementation methodologies for both controllers. Expected results are verified by simulation and a build-up prototype. It was shown that the VIENNA rectifier is able to convert a generator type input, with variable input voltage amplitude and variable frequency, to a constant DC-bus voltage whilst controlling the input current to be sinusoidal and in phase with the input voltage. The rectifier was able to maintain a constant DC voltage at the output for input voltages as low as half the rated input voltage and for an equivalent output power of half the rated output power. This suggests that the VIENNA rectifier, controlled as a dual-boost rectifier, is suitable for applications that require power factor corrections and simultaneously operate from a wide input voltage range. / Dissertation (MEng (Electrical Engineering))--University of Pretoria, 2007. / Electrical, Electronic and Computer Engineering / MEng / unrestricted

The current high demand for sustainable and renewable energy sources to solve world energy crisis has enormously increased interest in looking at alternative sources of energy. All the machines used in manufacturing process, electricity generation, residential applications, transportation etc., rejects energy in the form of heat into environment. Thermoelectric materials can convert thermal-to-electrical and electrical-to-thermal energy and can be utilized in waste-heat harvesting, more efficient cooling to reduce energy usage and CO2 emissions. Significant research efforts have been devoted over the past decade to thermoelectric materials, with particular emphasis being placed on combining materials selection with nanostructuring. The overarching goal was to reduce thermal conductivity through selective phonon scattering and thus boost the thermoelectric figure-of-merit (ZT). SiGe alloys, as well as superlattices and nanocomposites made from them, showed significant improvements upon nanostructuring and ZT exceeding one at high temperatures. Other group IV alloys were not studied in the context of thermoelectrics. However, SiSn alloys are widely studied for their optoelectronic properties because they were predicted to become direct-gap materials when Sn composition increased beyond about 50%. To address this gap, we study the thermoelectric properties of SiSn alloys. Furthermore, we develop an iterative full-band solver for the electron Boltzmann transport equation and use it to compute the electron and hole mobility and Seebeck coeffcient in SiSn alloys. The electronic structure of SiSn alloys was computed in the virtual crystal approximation from non-local empirical pseudopotentials, while the application of strain allowed us to extract the electron-phonon coupling deformation potentials for each alloy composition. We benchmark our code against available mobility data for Si and SiGe alloys and find that it accurately reproduces the measured values. Full phonon dispersion was computed from the adiabatic bond charge model, which was shown to accurately reproduce measured dispersion, and used in our phonon BTE solver to compute lattice thermal conductivities. Scattering rates include anharmonic phonon-phonon, impurity, isotope, alloy, and boundary mechanisms. The lowest thermal conductivity was obtained in SiSn alloys, which have been experimentally demonstrated with up to 18% Sn composition. This carries through when combined with calculations of electronic power factor, where mobilities and Seebeck coeffcients of SiSn alloys are comparable to those of SiGe. Furthermore, ZT is optimized through doping for every composition. The ZT improves dramatically at higher temperatures, reaching ZT of 1.9, 2.36 is obtained for Sn composition of 10% and 50% in a n-doped bulk SiSn alloys at a temperature of 1480 K. However, such high Sn composition of 50% is unlikely to be synthesized due to low solid solubility of Sn in Si. Lastly, we study the impact of nanostructuring in thin films on the ZT. We also establish the limits on how much the ZT can be improved through nanostructuring by studying thin films of SiSn alloys across temperature from room temperature up to 1500 K. We conclude that in bulk SiSn alloys, even at modest Sn concentration of 10%, ZT can reach 1.9, while in 20 nm thin films of n-type SiSn alloys, it can reach the long-sought target of ZT>3 and ZT of 2.16 is obtained in p-type nanostructured SiSn alloys.

This paper presents the design and development of a novel Arc Welding Power Supply utilizing a modified two-switch forward converter topology. The proposed design improves the power quality by improving power factor to near unity and reducing total harmonic distortion. State space analysis of the proposed circuit showed that the circuit followed a boost-buck input output relationship. Simulation of the circuit was first implemented in LTspice to verify the functionality of the new topology. Hardware implementation of the proposed design was built on a scaled-down prototype for a proof-of-concept of the new topology. The prototype specifications were created for a 5A, 20V output with a 20-24V, 60Hz input. This project demonstrated that the proposed new topology was successful in obtaining a near unity power factor and a total harmonic distortion of less than 2%. Additionally, the prototype followed the simulation and calculations of a boost-buck function while varying duty cycle, and the final measurements aligned well with waveforms from the simulation.

This master thesis deals with design of DC-DC converter for onboard charging of electric vehicle. Developed converter will mainly be used for charging stationary traction battery in laboratory. Output voltage of this charger will be adjustable by user in between 200 V and 450 V depending on the current charged battery configuration. Output current limit is set at 8 A. Since the converter will be supplied from standard household socket, the problem of power factor correction must be solved during the design. That is because a large part of this thesis is focused on describing the problematics of power factor correction. After that, active PFC module is designed, completed and performance of this module is verified. To achieve low overall losses and thus be able to keep small volume of the system, modern switching components based on Silicon Carbide were preferred. Beside laboratory use, completed system will be used to emphasize volumetric difference between onboard chargers based on old versus modern switching components.

This Diploma thesis deals with design of for power factor correction device for mid-frequency-range induction heating and also with assessment of correction device influence in harmonically distorted environment from the distribution net point of view. Research chapters contain of main characteristics of electrical power quality and theoretical background of reactive power, which is in our case caused by driven non-linear elements. Further, the heating power supply block is explained and simulations of power consumption in Matlab - Simulink is done, within the prove of corrective tools design. After the build of corrective tool assemblies, measurements are matched with the simulation results.