Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-04-19T19:08:59Z No. of bitstreams: 1 filipecaixeiromattos.pdf: 2641141 bytes, checksum: 014bbdead0d71ad1d9852cb7403b3439 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-04-20T12:46:42Z (GMT) No. of bitstreams: 1 filipecaixeiromattos.pdf: 2641141 bytes, checksum: 014bbdead0d71ad1d9852cb7403b3439 (MD5) / Made available in DSpace on 2017-04-20T12:46:42Z (GMT). No. of bitstreams: 1 filipecaixeiromattos.pdf: 2641141 bytes, checksum: 014bbdead0d71ad1d9852cb7403b3439 (MD5) Previous issue date: 2011-09-02 / Esta dissertação apresenta uma contribuição ao estudo de um inversor de tensão monofásico (VSI – Voltage Source Inverter), com saída em corrente, aplicado ao processamento de energia em sistemas solares fotovoltaicos (PV) monofásicos conectados à rede elétrica de distribuição. Através do controle por corrente média, é possível em um único estágio de processamento de energia rastrear o ponto de máxima potência do arranjo fotovoltaico e injetar na rede elétrica uma corrente com baixa distorção harmônica total (THD) e em fase com a tensão da rede CA. Para implementação do controle do sistema é utilizado o circuito integrado UC3854, da Texas Instruments, componente analógico de baixo custo e com funções típicas de correção de fator de potência de fontes de alimentação. Equações de análise e projeto, resultados de simulação e informações experimentais, obtidas de um protótipo de 720W, são incluídos neste material. / This dissertation presents a contribution to the study of a single-phase voltage inverter (VSI – Voltage Source Inverter), with current output, applied to the processing of photovoltaic (PV) solar power connected to single-phase electric distribution network. By controlling the average current, it is possible, in a single stage of power processing, to track the maximum power point of PV array and inject into the grid a current with low total harmonic distortion (THD) and in phase with the AC mains voltage. To implement the control system it is used a low cost Texas Instruments' analog integrated circuit UC3854, which includes a power factor correction typical function. Equations concerning analysis and design steps, simulation results and experimental data obtained from a 720W prototype are included in this document.

Two related bodies of work are presented, both of which aim to further the rapid development of next generation concentrating photovoltaic systems using high efficiency multi junction solar cells. They are complementary since the characterization of commercial devices and the systematic application of design principles for future designs must progress in parallel in order to accelerate iterative improvements. First addressed, is the field characterization of state of the art concentrating photovoltaic systems. Performance modeling and root cause analysis of deviations from the modeling results are critical for bringing reliable high value products to the market. Two complementary tools are presented that facilitate acceleration of the development cycle. The “Dynamic real-time I V Curve Measurement System…” provides a live picture of the current-voltage characteristics of a CPV module. This provides the user with an intuitive understanding of how module performance responds under perturbation. The “Shutter technique for noninvasive individual cell characterization in sealed concentrating photovoltaic modules,” allows the user to probe individual cell characteristics within a sealed module. This facilitates non-invasive characterization of modules that are in situ. Together, these tools were used to diagnose the wide spread failure of epoxy connections between the carrier and the emitter of bypass diodes installed in sealed commercial modules. Next, the optimization principals that are used to choose energy yield maximizing bandgap combinations for multi-junction solar cells are investigated. It is well understood that, due to differences in the solar resource in different geographical locations, this is fundamentally a local optimization problem. However, until now, a robust methodology for determining the influences of geography and atmospheric content on the ideal design point has not been developed. This analysis is presented and the influence of changing environment on the representative spectra that are used to optimize bandgap combinations is demonstrated. Calculations are confirmed with ground measurements in Ottawa, Canada and the global trends are refined for this particular location. Further, as cell designers begin to take advantage of more flexible manufacturing processes, it is critical to know if and how optimization criteria must change for solar cells with more junctions. This analysis is expanded to account for the differences between cells with up to 8 subcell bandgaps. A number of software tools were also developed for the Sunlab during this work. A multi-junction solar cell model calibration tool was developed to determine the parameters that describe each subcell. The tool fits a two diode model to temperature dependent measurements of each subcell and provides the fitting parameters so that the performance of multi-junction solar cells composed of those subcells can be modeled for real world conditions before they are put on-sun. A multi-junction bandgap optimization tool was developed to more quickly and robustly determine the ideal bandgap combinations for a set of input spectra. The optimization process outputs the current results during iteration so that they may be visualized. Finally, software tools that compute annual energy yield for input multi-junction cell parameters were developed. Both a brute force tool that computes energy harvested at each time step, and an accelerated tool that first bins time steps into discrete bins were developed. These tools will continue to be used by members of the Sunlab.

Global economic trends suggest that there is a need to generate sustainable renewable energy to meet growing global energy demands. Solar energy harnessed by concentrated photovoltaic (CPV) systems has a potential for strong contributions to future energy supplies. However, as a relatively new technology, there is still a need for considerable research into the relationship between the technology and the solar resource. Research into CPV systems was carried out at the University of Ottawa’s Solar Cells and Nanostructured Device Laboratory (SUNLAB), focusing on the acquisition and assessment of meteorological and local solar resource datasets as inputs to more complex system (cell) models for energy yield assessment. An algorithm aimed at estimating the spectral profile of direct normal irradiance (DNI) was created. The algorithm was designed to use easily sourced low resolution meteorological datasets, temporal band pass filter measurement and an atmospheric radiative transfer model to determine a location specific solar spectrum. Its core design involved the use of an optical depth parameterization algorithm based on a published objective regression algorithm. Initial results showed a spectral agreement that corresponds to 0.56% photo-current difference in a modeled CPV cell when compared to measured spectrum. The common procedures and datasets used for long term CPV energy yield assessment was investigated. The aim was to quantitatively de-convolute various factors, especially meteorological factors responsible for error bias in CPV energy yield evaluation. Over the time period from June 2011 to August 2012, the analysis found that neglecting spectral variations resulted in a ~2% overestimation of energy yields. It was shown that clouds have the dominant impact on CPV energy yields, at the 60% level.

This thesis deals with using thermography to detect defect of photovoltaic panels.There is research of the effect of climatic conditions to photovoltaic panel temperature. At the end of the thesis is degradation of pv panels calculated.

Orientador: Júlio Borges de Souza / Resumo: Este trabalho apresenta uma avaliação dos aspectos da instalação de sistemas de geração distribuída fotovoltaica (GDFV) em unidades consumidoras sujeitas à cobrança de reativos no Brasil. A avaliação dos possíveis impactos técnicos e financeiro é realizada sob o alicerce da legislação e normativas aplicáveis. São abordados os modos de medição, sistema tarifário aplicado à unidade em estudo, bem como um comparativo com outros tipos de unidades consumidoras com geração distribuída (GD). São realizadas projeções de funcionamento em condições definidas, faz-se uso do equacionamento definido pela legislação e normas vigentes. Também é realizado um estudo de caso em uma unidade consumidora real. Como resultado apresentam-se gráficos que ilustram o comportamento da curva de geração fotovoltaica, consumo demandado, consumo medido, bem como o comportamento do fator de potência em unidades com GDFV instalada. Isto viabiliza a aferição de eventuais pontos positivos e negativos da instalação de GD nesse tipo de unidade consumidora. No estudo de caso também são apresentadas, em forma de tabela, os valores e percentuais de economia da unidade, comparando com o período sem GDFV. Por fim, são avaliados os possíveis impactos no tempo de retorno do investimento, contribuições negativas na qualidade de energia do sistema elétrico e apresentadas propostas de soluções para sanar ou atenuar os problemas encontrados. / Abstract: This paper presents an evaluation of the aspects of the installation of photovoltaic distributed generation systems in consumer units subjected to reactive charging in Brazil. The assessment of possible technical and financial impacts is carried out on the basis of applicable legislation and regulations. Measurement modes are addressed, the tariff system applied to the unit studied, a comparison is made with other types of consumer units with distributed generation (DG). Operating projections are carried out under defined conditions, using the equation defined by current legislation and standards. A case study is also performed in a real consumer unit. As a result we present graphs that illustrate the behavior of the photovoltaic generation curve, demanded consumption, measured consumption, as well as the behavior of the power factor in units with installed photovoltaic distributed generation system. This makes it possible to measure any positive and negative points of the installation of DG in this type of consumer unit. In the case study are also presented in table form the values and percentages of economy of the unit, comparing with the period without distributed photovoltaic generation. Finally, the possible impacts on return on investment time, negative contributions on the electric power quality of the electric system are evaluated and proposals of solutions to solve or mitigate the problems are presented. / Mestre

L'intégration actuelle des systèmes photovoltaïques dans les systèmes d'alimentation conventionnels a montré une croissance importante, ce qui a favorisé l'expansion rapide des micro-réseaux du terme anglais microgrid. Cette intégration a cependant augmenté la complexité du système d'alimentation qui a conduit à de nouveaux défis de recherche. Certains de ces défis de recherche encouragent le développement d'approches de modélisation innovantes en temps réel capables de faire face à cette complexité croissante. Dans ce contexte, une méthodologie innovante est proposée et basée sur les composants pour la modélisation et l'émulation de systèmes photovoltaïques en temps réel integers aux microgrids. L'approche de modélisation proposée peut utiliser le langage de modélisation des systèmes (SysML) pour décrire la structure et le comportement des systèmes photovoltaïques intégrés en tenant compte de leurs caractéristiques multidisciplinaires. De plus, cette étude présente le cadre de spécification de haut niveau des systèmes embarqués (HiLeS) pour transformer les modèles SysML développés en code source destinés à configurer le matériel intégré. Cette caractéristique de la generation automatique de code permet de profiter de dispositifs avec un haut degré d'adaptabilité et de performances de traitement. Cette méthodologie basée sur HiLeS et SysML est axée sur l'étude des systems photovoltaïques partiellement ombragés ainsi que des architectures flexibles en électronique de puissance en raison de leur influence sur les microgrids actuels. En outre, cette perspective de recherche est utilisée pour évaluer les stratégies de contrôle et de supervision dans les conditions normales et de défauts. Ce travail représente la première étape pour développer une approche innovante en temps réel pour modéliser et émuler des systèmes photovoltaïques complexes en tenant compte des propriétés de modularité, de haut degré d'évolutivité et des conditions de travail non uniformes. Les résultats expérimentaux et analytiques valident la méthodologie proposée. / Nowadays, the integration of photovoltaic systems into electrical grids is encouraging the expansion of microgrids. However, this integration has also increased the power system complexity leading to new research challenges. Some of these research challenges require the development of innovative modeling approaches able to deal with this increasing complexity. Therefore, this thesis is intended to contribute with an innovative methodology component-based for modeling and emulating in real-time photovoltaic systems integrated to microgrids. The proposed modeling approach uses the Systems Modeling Language (SysML) to describe the structure and behavior of integrated photovoltaic systems. In addition, this study presents the High Level Specification of Embedded Systems (HiLeS) to transform automatically the developed SysML models in embedded code and Petri nets. These characteristics of automatic code generation and design based on Petri nets allow taking advantage of FPGAs for application of real-time emulation of photovoltaic systems. This dissertation is focused on partially shaded photovoltaic systems and flexible power electronics architectures because of their relevant influence on current microgrids. Furthermore, this research perspective is intended to evaluate control and supervision strategies in normal and fault conditions. This work represents the first step to develop an innovative real-time approach to model and emulate complex photovoltaic systems considering properties of modularity, high degree of scalability, and non-uniform working conditions. Finally, experimental and analytical results validate the proposed methodology.

[pt] Com a necessidade de uma maior diversificação da matriz energética mundial e a inevitabilidade de investimento em fontes de energia limpa, a energia solar fotovoltaica tem se mostrado uma fonte energética promissora. Seu crescimento hoje é exponencial e se revela cada vez mais presente na matriz energética da maioria dos países. No Brasil, já se vê um mercado fotovoltaico sólido com geração de milhares de empregos e investimentos de bilhões de reais. Sua intermitência e imprevisibilidade é razão de grande pesquisa, no intuito de obter dados confiáveis que estimam a geração de um sistema solar fotovoltaico ao longo de seu ciclo de vida. Sendo assim, este trabalho conduz uma extensa revisão bibliográfica, passando pelos fundamentos básicos, até o desenvolvimento de um algorítmico robusto, integrando modelos matemáticos presentes na literatura. Os dados de radiação solar global, velocidade do vento e temperatura, são obtidos de mapas gerados por 39 estações solarimétricas dentro e próximas das fronteiras do estado do Rio de Janeiro. O simulador, também conta com uma extensa base de dados atual de módulos solares e inversores. Após uma série de validações e análises de sensibilidade, apresentou resultados satisfatórios quanto a sua capacidade de previsão. Dessa forma, é possível simular e dimensionar sistemas solares fotovoltaicos, calculando indicadores e fluxo de caixa detalhado que refletem a viabilidade de um determinado projeto. Além disso, o simulador tem a capacidade de gerar mapas georreferencidos que contribuem para uma avaliação técnica, economia e ambiental, de uma região a ser analisada. Com isso, se torna uma ferramenta fundamental para investidores do setor. / [en] With the need for greater diversification of the world energy matrix and the inevitability of investment in clean energy sources, photovoltaic solar energy has proved to be a promising energy source. Its growth today is exponential and is increasingly present in the energy matrix of most countries. In Brazil, there is already a solid photovoltaic market with the generation of thousands of jobs and investments of billions of reais. Its intermittency and unpredictability is the reason for great research, in order to obtain reliable data that estimate the generation of a photovoltaic solar system throughout its life cycle. Therefore, this work conducts an extensive bibliographic review, going through the basic foundations, until the development of a robust algorithm, integrating mathematical models present in the literature. Global solar radiation, wind speed and temperature data are obtained from maps generated by 39 solarimetric stations within and near the borders of the state of Rio de Janeiro. The simulation tool also has an extensive current database of solar modules and inverters. After a series of validations and sensitivity analyzes, it presented satisfactory results in terms of its forecasting capacity. In this way, it is possible to simulate and size solar photovoltaic systems, calculating indicators and detailed cash flow that reflect the viability of a given project. In addition, the simulation tool has the ability to generate georeferenced maps that contribute to a technical, economic and environmental assessment of a region to be analyzed. As a result, it becomes a fundamental tool for investors in the sector.

No description available.

This study provides an analysis of the benefits of adding solar PV and batteries to industries, both examing the grid-connected and off-grid cases.The electricity demand of 28 companies in Falkenberg, Sweden, whose industries require high voltages for electricity, were studied. We examined the extent to which these companies can depend on energy generated from photovoltaic cells and stored in batteries, as well as the impact of peak loads and the possibility of eliminating peaks when operating off-grid.The data for each of these cases were analyzed for companies to determine the energy that can be generated from photovoltaic cells on-site, and then take advantage of this energy directly and store the surplus in batteries to reduce dependence on the grid or reduce this dependence to a minimum, and study the role of the battery. We obtained interesting results and reliable systems during this study, as we noticed the effect of changing working hours in these companies in proportion to the times of energy production during the period of daily solar radiation.By studying the main load models in these companies and using the results and data analysis, it was noted that batteries can be a reliable solution, in which the energy generated from solar cells is used directly and the excess electricity is stored in the batteries later, and we noted the possibility of operating the entire system off-grid, which was found realistic if the company would have been located in Egypt. .

Este trabalho propõe um sistema fotovoltaico (PV) multifuncional conectado a um sistema elétrico trifásico a quatro fios e operando com estratégia dual de compensação ativa de potência. Além da injeção de potência ativa na rede elétrica, o sistema PV operara como um condicionador unificado de qualidade de energia (UPQC) suprimindo as correntes harmônicas da carga e compensando a potência reativa. Adicionalmente, tensões balanceadas, reguladas e livre de harmônicos são fornecidas para a carga. O sistema PV-UPQC é baseado em uma estratégia de compensação dual, na qual o conversor série opera como uma fonte de corrente senoidal, enquanto o conversor paralelo atua como uma fonte de tensão senoidal. Como resultado, nenhum comportamento transitório é observado na troca entre os modos de operação ilhado e interconectado do sistema PV-UPQC. Além disso, para contornar os problemas associados às mudanças bruscas de irradiação solar, uma malha de controle feed-forward atua na geração das referências de corrente do conversor série, de modo que se obtenha um rápido balanço de potência entre o sistema PV e a rede elétrica. Como resultado, as respostas dinâmicas tanto da corrente elétrica quanto da tensão do barramento CC são melhoradas. A análise detalhada envolvendo o fluxo de potência ativa dos inversores é realizada proporcionando um melhor entendimento sobre a operação do sistema PV-UPQC, bem como auxiliando no dimensionamento dos conversores de potência. Resultados de simulação e experimentais são apresentados para avaliar os desempenhos estáticos e dinâmicos do PV-UPQC conectado ao sistema elétrico de distribuição. / This work proposes a multifunctional single-stage three-phase four-wire grid-connected photovoltaic (PV) system operating with a dual active power-line compensating strategy. Besides injection of active power into the grid, the PV system operates as a unified power quality conditioner (UPQC), suppressing the load harmonic currents and compensating reactive power. Additionally, regulated, balanced and harmonic free output voltages are provided to the load. Since the PV-UPQC is based on a dual compensation strategy, the series converter operates as a sinusoidal current source, whereas the parallel converter operates as a sinusoidal voltage source. Thus, seamless transition can be achieved from the interconnected to the islanding operation modes, and vice-versa, without load voltage transients. Moreover, to overcome problems associated with sudden solar irradiation changes, fast power balance involving the PV array and the grid is obtained, since the feed-forward control loop acts on the generation of the series inverter current references. As a result, the dynamic responses of both inverter currents and dc-bus voltage are improved. Detailed analysis involving the active power flow through the inverters is performed allowing proper understanding of the PV-UPQC operation, as well as assisting to design of the power converters. Simulation and experimental results are presented to evaluate both dynamic and static performances of the PV-UPQC tied to the electrical distribution system.