abstract: With the increasing penetration of Photovoltaic inverters, there is a necessity for recent PV inverters to have smart grid support features for increased power system reliability and security. The grid support features include voltage support, active and reactive power control. These support features mean that inverters should have bidirectional power and communication capabilities. The inverter should be able to communicate with the grid utility and other inverter modules. This thesis studies the real time simulation of smart inverters using PLECS Real Time Box. The real time simulation is performed as a Controller Hardware in the Loop (CHIL) real time simulation. In this thesis, the power stage of the smart inverter is emulated in the PLECS Real Time Box and the controller stage of the inverter is programmed in the Digital Signal Processor (DSP) connected to the real time box. The power stage emulated in the real time box and the controller implemented in the DSP form a closed loop smart inverter. This smart inverter, with power stage and controller together, is then connected to an OPAL-RT simulator which emulates the power distribution system of the Arizona State University Poly campus. The smart inverter then sends and receives commands to supply power and support the grid. The results of the smart inverter with the PLECS Real time box and the smart inverter connected to an emulated distribution system are discussed under various conditions based on the commands received by the smart inverter. / Dissertation/Thesis / Masters Thesis Electrical Engineering 2017

abstract: The automotive industry is committed to moving towards sustainable modes of transportation through electrified vehicles to improve the fuel economy with a reduced carbon footprint. In this context, battery-operated hybrid, plug-in hybrid and all-electric vehicles (EVs) are becoming commercially viable throughout the world. Lithium-ion (Li-ion) batteries with various active materials, electrolytes, and separators are currently being used for electric vehicle applications. Specifically, lithium-ion batteries with Lithium Iron Phosphate (LiFePO4 - LFP) and Lithium Nickel Manganese Cobalt Oxide (Li(NiMnCo)O2 - NMC) cathodes are being studied mainly due to higher cycle life and higher energy density values, respectively. In the present work, 26650 Li-ion batteries with LFP and NMC cathodes were evaluated for Plug-in Hybrid Electric Vehicle (PHEV) applications, using the Federal Urban Driving Schedule (FUDS) to discharge the batteries with 20 A current in simulated Arizona, USA weather conditions (50 ⁰C & <10% RH). In addition, 18650 lithium-ion batteries (LFP cathode material) were evaluated under PHEV mode with 30 A current to accelerate the ageing process, and to monitor the capacity values and material degradation. To offset the high initial cost of the batteries used in electric vehicles, second-use of these retired batteries is gaining importance, and the possibility of second-life use of these tested batteries was also examined under constant current charge/discharge cycling at 50 ⁰C. The capacity degradation rate under the PHEV test protocol for batteries with NMC-based cathode (16% over 800 cycles) was twice the degradation compared to batteries with LFP-based cathode (8% over 800 cycles), reiterating the fact that batteries with LFP cathodes have a higher cycle life compared to other lithium battery chemistries. Also, the high frequency resistance measured by electrochemical impedance spectroscopy (EIS) was found to increase significantly with cycling, leading to power fading for both the NMC- as well as LFP-based batteries. The active materials analyzed using X-ray diffraction (XRD) showed no significant phase change in the materials after 800 PHEV cycles. For second-life tests, these batteries were subjected to a constant charge-discharge cycling procedure to analyze the capacity degradation and materials characteristics. / Dissertation/Thesis / Masters Thesis Materials Science and Engineering 2017

Made available in DSpace on 2015-05-08T14:57:17Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 2159894 bytes, checksum: 0afcf73fa1c2d4c1bf3a43ee27852d53 (MD5) Previous issue date: 2014-02-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Currently possible solutions for alternative electric power generation have been the subject of interest of many researchers. Many of these studies focus on the use of natural resources, theoretically inexhaustible, to preserve exhaustible sources of energy. More recently, it has been studied the possibility of generating low power electricity, but enough to meet the demand of some electronic systems. Systems such as wireless sensors or remote communication which has low power consumption can be benefited. Among various technologies for producing alternative electricity, the use of vibratory energy and deformation of structures can be used to generate electricity. This conversion has the piezoelectric materials that convert mechanical strain energy into electrical energy. Thus, this work presents the characterization study of a piezoelectric material, Lead Zirconate Titanate (PZT), with the purpose of generating electricity. For the characterization experiment, we used a cylindrical PZT subjected to compression in a cyclic manner in the axial direction. An experimental apparatus was designed and instrumented to capture the force, acceleration, voltage and electric power generated due to piezoelectric cell. Initially simulations were developed in order to guide the experimental set of actions. From the experimental results with a piezoelectric cell a piezoelectric generator was designed with three cells and characterized. Results of the physical parameters related to characterization are presented. / Atualmente tem sido alvo de interesse de muitos pesquisadores estudos que apresentem possíveis soluções para geração de energia elétrica alternativa. Muitas dessas pesquisas se concentram na utilização de recursos naturais, teoricamente inesgotáveis, para preservar outras fontes de energias esgotáveis. Mais recentemente, tem sido estudada a possibilidade de geração de energia elétrica de baixa potência, mas que seja suficiente para suprir a demanda de alguns sistemas eletrônicos. Sistemas como sensores sem fio ou comunicação remota que tem baixo consumo de potência podem ser beneficiados. Dentre as várias tecnologias de produção de energia elétrica alternativa, o uso da energia vibratória e de deformação de estruturas pode ser utilizada para gerar energia elétrica. Para essa conversão se tem os materiais piezoelétricos que convertem a energia de deformação mecânica em energia elétrica. Assim, neste trabalho, é apresentado o estudo de caracterização de um material piezoelétrico de Titanato Zirconato de Chumbo (PZT) com o objetivo de geração de energia elétrica. Para a caracterização experimental foi utilizado um PZT com geometria cilíndrica tubular, submetido a uma compressão de forma cíclica no sentido axial. Um aparato experimental foi criado e instrumentado para a captação da força, aceleração, tensão e potência elétrica gerada devido a célula piezoelétrica. Inicialmente simulações foram desenvolvidas no sentido de nortear o conjunto de ações experimentais. A partir dos resultados experimentais com uma célula piezoelétrica foi elaborado um gerador piezoelétrico com três células e caracterizado. Resultados dos parâmetros físicos relacionados às caracterizações são apresentados.

Orientador: Carlos Alberto Canesin / Banca: Jean Marcos de Souza Ribeiro / Banca: Guilherme de Azevedo e Melo / Banca: Antonio Marcus Nogueira Lima / Banca: Azauri Albano e Oliveira Junior / Resumo: Considerando a necessidade do controle de fluxo de energia elétrica nos cenários futuros de Geração Distribuída (GD), local e/ou regionalizado, este trabalho de doutorado propõe uma metodologia de controle do fluxo de potências ativa e reativa, aplicada para inversores monofásicos e trifásicos conectados à rede de distribuição em baixa tensão, utilizando as técnicas de controles baseadas nas desigualdades matriciais lineares (LMI) em conjunto com conceitos da Ɗ-Estabilidade e realimentação de estados como critério de linearização dos sistemas. O controle do fluxo de potências é baseado nas curvas de transferência de potências P-ω e Q-V (análogas a P-f (Potência Ativa-Frequência) e Q-V (Potência Reativa-Tensão)), num sistema de controle multimalhas. A metodologia multimalhas empregada no trabalho utiliza a técnica de realimentações de estados, melhorando o desempenho do controlador e atenuando possíveis distúrbios e perturbações que venham a ocorrer no sistema. Além disso, a metodologia proposta tem o objetivo de obter o melhor controlador com o menor ganho dentro da região esquerda do plano-s especificada durante o projeto, apresentando respostas rápidas com oscilações mínimas. O trabalho apresenta resultados de simulações e experimentais considerando um protótipo monofásico com uma potência nominal de 1000VA e um protótipo trifásico com uma potência nominal de 3000VA, com a finalidade de demonstrar e analisar o funcionamento das técnicas de controle propostas. / Abstract: Considering the necessity of local and/or regionalized electric energy control flow in the future scenario of Distributed Generation (DG), this doctorate work proposes a methodology of control for active and reactive electric powers, applied to single and three-phase grid-tie inverters at low-voltage electrical distribution networks, using the techniques of control based on Linear Matrix Inequalities (LMI) along with the concepts of Ɗ-stability and feedback state as a criterion of linearization systems. The power flow control is based on power transfer curves P-ω and Q-V (similar to P-f (Active Power - Frequency) and Q-V (Reactive Power - Voltage)), in a multi-loop control system. The multi-loop control applied in this work uses the technique of feedback states in order to improve the performance of controller and to attenuate possible disturbs and perturbations that could happen in the system. Moreover, the proposed methodology has the objective to obtain the best controller with the lowest gain in the left-half s-plane region specified during the design, showing fast responses with minimal oscillations. This work presents the simulation and experimental results considering a single-phase prototype with 1000VA rated power and a three-phase prototype with 3000VA rated power, in order to demonstrate and analyze the proposed control operation. / Doutor

abstract: Alternative energy technologies must become more cost effective to achieve grid parity with fossil fuels. Dye sensitized solar cells (DSSCs) are an innovative third generation photovoltaic technology, which is demonstrating tremendous potential to become a revolutionary technology due to recent breakthroughs in cost of fabrication. The study here focused on quality improvement measures undertaken to improve fabrication of DSSCs and enhance process efficiency and effectiveness. Several quality improvement methods were implemented to optimize the seven step individual DSSC fabrication processes. Lean Manufacturing's 5S method successfully increased efficiency in all of the processes. Six Sigma's DMAIC methodology was used to identify and eliminate each of the root causes of defects in the critical titanium dioxide deposition process. These optimizations resulted with the following significant improvements in the production process: 1. fabrication time of the DSSCs was reduced by 54 %; 2. fabrication procedures were improved to the extent that all critical defects in the process were eliminated; 3. the quantity of functioning DSSCs fabricated was increased from 17 % to 90 %. / Dissertation/Thesis / M.S.Tech Technology 2012

abstract: Microgrids are a subset of the modern power structure; using distributed generation (DG) to supply power to communities rather than vast regions. The reduced scale mitigates loss allowing the power produced to do more with better control, giving greater security, reliability, and design flexibility. This paper explores the performance and cost viability of a hybrid grid-tied microgrid that utilizes Photovoltaic (PV), batteries, and fuel cell (FC) technology. The concept proposes that each community home is equipped with more PV than is required for normal operation. As the homes are part of a microgrid, excess or unused energy from one home is collected for use elsewhere within the microgrid footprint. The surplus power that would have been discarded becomes a community asset, and is used to run intermittent services. In this paper, the modeled community does not have parking adjacent to each home allowing for the installment of a privately owned slower Level 2 charger, making EV ownership option untenable. A solution is to provide a Level 3 DC Quick Charger (DCQC) as the intermittent service. The addition of batteries and Fuel Cells are meant to increase load leveling, reliability, and instill limited island capability. / Dissertation/Thesis / M.S.Tech Engineering 2013

abstract: The object of this study was a 26 year old residential Photovoltaic (PV) monocrystalline silicon (c-Si) power plant, called Solar One, built by developer John F. Long in Phoenix, Arizona (a hot-dry field condition). The task for Arizona State University Photovoltaic Reliability Laboratory (ASU-PRL) graduate students was to evaluate the power plant through visual inspection, electrical performance, and infrared thermography. The purpose of this evaluation was to measure and understand the extent of degradation to the system along with the identification of the failure modes in this hot-dry climatic condition. This 4000 module bipolar system was originally installed with a 200 kW DC output of PV array (17 degree fixed tilt) and an AC output of 175 kVA. The system was shown to degrade approximately at a rate of 2.3% per year with no apparent potential induced degradation (PID) effect. The power plant is made of two arrays, the north array and the south array. Due to a limited time frame to execute this large project, this work was performed by two masters students (Jonathan Belmont and Kolapo Olakonu) and the test results are presented in two masters theses. This thesis presents the results obtained on the north array and the other thesis presents the results obtained on the south array. The resulting study showed that PV module design, array configuration, vandalism, installation methods and Arizona environmental conditions have had an effect on this system's longevity and reliability. Ultimately, encapsulation browning, higher series resistance (potentially due to solder bond fatigue) and non-cell interconnect ribbon breakages outside the modules were determined to be the primary causes for the power loss. / Dissertation/Thesis / M.S.Tech Electrical Engineering 2013

abstract: Novel materials for Li-ion batteries is one of the principle thrust areas for current research in energy storage, more so than most, considering its widespread use in portable electronic gadgets and plug-in electric and hybrid cars. One of the major limiting factors in a Li-ion battery's energy density is the low specific capacities of the active materials in the electrodes. In the search for high-performance anode materials for Li-ion batteries, many alternatives to carbonaceous materials have been studied. Both cubic and amorphous silicon can reversibly alloy with lithium and have a theoretical capacity of 3500 mAh/g, making silicon a potential high density anode material. However, a large volume expansion of 300% occurs due to changes in the structure during lithium insertion, often leading to pulverization of the silicon. To this end, a class of silicon based cage compounds called clathrates are studied for electrochemical reactivity with lithium. Silicon-clathrates consist of silicon covalently bonded in cage structures comprised of face sharing Si20, Si24 and/or Si28 clusters with guest ions occupying the interstitial positions in the polyhedra. Prior to this, silicon clathrates have been studied primarily for their superconducting and thermoelectric properties. In this work, the synthesis and electrochemical characterization of two categories of silicon clathrates - Type-I silicon clathrate with aluminum framework substitution and barium guest ions (Ba8AlxSi46-x) and Type-II silicon clathrate with sodium guest ions (Nax Si136), are explored. The Type-I clathrate, Ba8AlxSi46-x consists of an open framework of aluminium and silicon, with barium (guest) atoms occupying the interstitial positions. X-ray diffraction studies have shown that a crystalline phase of clathrate is obtained from synthesis, which is powdered to a fine particle size to be used as the anode material in a Li-ion battery. Electrochemical measurements of these type of clathrates have shown that capacities comparable to graphite can be obtained for up to 10 cycles and lower capacities can be obtained for up to 20 cycles. Unlike bulk silicon, the clathrate structure does not undergo excessive volume change upon lithium intercalation, and therefore, the crystal structure is morphologically stable over many cycles. X-ray diffraction of the clathrate after cycling showed that crystallinity is intact, indicating that the clathrate does not collapse during reversible intercalation with lithium ions. Electrochemical potential spectroscopy obtained from the cycling data showed that there is an absence of formation of lithium-silicide, which is the product of lithium alloying with diamond cubic silicon. Type II silicon clathrate, NaxSi136, consists of silicon making up the framework structure and sodium (guest) atoms occupying the interstitial spaces. These clathrates showed very high capacities during their first intercalation cycle, in the range of 3,500 mAh/g, but then deteriorated during subsequent cycles. X-ray diffraction after one cycle showed the absence of clathrate phase and the presence of lithium-silicide, indicating the disintegration of clathrate structure. This could explain the silicon-like cycling behavior of Type II clathrates. / Dissertation/Thesis / M.S. Materials Science and Engineering 2013

abstract: The utilization of solar energy requires an efficient means of its storage as fuel. In bio-inspired artificial photosynthesis, light energy can be used to drive water oxidation, but catalysts that produce molecular oxygen from water are required. This dissertation demonstrates a novel complex utilizing earth-abundant Ni in combination with glycine as an efficient catalyst with a modest overpotential of 0.475 ± 0.005 V for a current density of 1 mA/cm<super>2</super> at pH 11. The production of molecular oxygen at a high potential was verified by measurement of the change in oxygen concentration, yielding a Faradaic efficiency of 60 ± 5%. This Ni species can achieve a current density of 4 mA/cm<super>2</super> that persists for at least 10 hours. Based upon the observed pH dependence of the current amplitude and oxidation/reduction peaks, the catalysis is an electron-proton coupled process. In addition, to investigate the binding of divalent metals to proteins, four peptides were designed and synthesized with carboxylate and histidine ligands. The binding of the metals was characterized by monitoring the metal-induced changes in circular dichroism spectra. Cyclic voltammetry demonstrated that bound copper underwent a Cu(I)/Cu(II) oxidation/reduction change at a potential of approximately 0.32 V in a quasi-reversible process. The relative binding affinity of Mn(II), Fe(II), Co(II), Ni(II) and Cu(II) to the peptides is correlated with the stability constants of the Irving-Williams series for divalent metal ions. A potential application of these complexes of transition metals with amino acids or peptides is in the development of artificial photosynthetic cells. / Dissertation/Thesis / Doctoral Dissertation Biological Design 2014

A atual situação de degradação ambiental tem sido muito discutida nos últimos anos. Um dos principais fatores agravantes dessa situação é a crescente demanda energética e suas atuais formas de produção. O petróleo, matriz energética mundial, é altamente poluente, e um combustível finito com o preço sempre crescente. A energia elétrica brasileira está baseada nas hidrelétricas, considerada fonte de energia limpa e renovável, porém o custo ambiental para sua construção é bem alto. Atualmente já existem tecnologias alternativas que podem servir essa crescente demanda energética sem prejudicar o meio ambiente. Na arquitetura, como em todas as áreas, houve um aumento com preocupação, e o estudo sobre o desempenho energético das edificações para reduzir a demanda de energia se tornou um assunto em pauta. Medidas e soluções estão sendo tomadas na decisão dos projetos mais sustentáveis. Mas para isso, o profissional deve estar atento às novas tecnologias alternativas de produção e distribuição de energia. Quando em um projeto é considerado o uso de fontes alternativas e o uso de técnicas de iluminação e ventilação natural, pode-se economizar não só nas despesas direcionadas para as fornecedoras de energia, mas poupar recursos naturais, ajudando a preservar o meio ambiente, fundamental para a nossa sobrevivência. Este trabalho traz algumas definições sobre sustentabilidade e a relação que a arquitetura tem com a problemática ambiental através da energia. Foi feita uma procura de novas tecnologias de produção e geração de energia e então, composto um estado da arte dos principais centros mundiais em P&D e dos projetos de demonstração envolvendo células à combustível, uma nova tecnologia que gera energia limpa in loco, descrevendo as características mais importantes destes projetos e compilando os resultados para uma possível adaptação aqui no Brasil, a fim de que diminua a participação das edificações no consumo de energia elétrica produzida a partir de hidrelétricas. O objetivo desta pesquisa é contribuir com a disseminação do conhecimento sobre energias alternativas e renováveis no meio arquitetônico, e demonstrar os principais centros mundiais em P&D e os projetos de demonstração que envolvam a geração de energia limpa através das células à combustível para uma adaptação no contexto brasileiro. Os resultados dessa pesquisa foram a constatação de que em todos países desenvolvidos há um forte apoio governamental para introdução dessa nova tecnologia de geração de energia para possibilitar futuramente a \"Economia do Hidrogênio\". A maioria dos projetos pesquisados são de células de tecnologia tipo PEM e abastecidas à gás natural (GN), pois esses países já possuem uma infra-estrutura formada para o GN. No contexto brasileiro, o apoio governamental à essa nova tecnologia ainda é pouco, salvo o fomento de algumas instituições como FAPESP, CAPES, CNPQ e centros universitários. Esta ausência governamental deixa espaço para respostas a curto prazo às novas demandas de energia elétrica ocasionando o preenchimento com outros tipos de fontes de energia poluentes e fósseis como é o caso do aumento das termelétricas ultimamente. / The current situation of environmental degradation has been much discussed in recent years. One of the main factors aggravating this situation is the growing energy demand and its current production methods most used. The oil, world energy matrix, is highly polluting fuel and a finite with the ever-increasing price. The Brazilian energy matrix is based on hydro, considered a clean and renewable source of energy, but the environmental cost and its construction are very high. Nowadays, there are alternative technologies that can serve this growing energy demand without harming the environment. In architecture, as in all areas, there was an increase in concern, and the study on the energy performance of buildings to reduce energy demand has become a subject matter. Measures and solutions are being taken in deciding the projects more sustainable. But for this, the practitioner must be aware of new alternative technologies of production and distribution of energy. When a project is considered the use of alternative techniques and the use of natural lighting and ventilation, you can save not only the costs directed for energy providers, but save natural resources, helping to preserve the environment, essential for our survival. This study offers some definitions of sustainability and the relationship that architecture has with the environment through energy. It was made a demand for new production technologies and power generation and then made a \"state of the art world\'s main centers of R&D and demonstration projects involving fuel cells, describing the most important features of these projects and compiling the results for a possible adjustment in Brazil, in order to decrease the participation of the buildings in the consumption of electricity produced from hydropower plants in Brazil. The research aims to contribute to the dissemination of knowledge on alternative and renewable energy among architectural and demonstrate the major world centers in R & D and demonstration projects involving the application of clean energy through fuel cells to adapt Brazilian context. The results of this research was the finding that in all developed countries there is strong government support for the introduction of this new technology to generate energy to enable a future \"Hydrogen Economy\". Most projects are cell PEM technology and supplied with natural gas because these countries already have an infrastructure set up to NG. In the Brazilian context, government support to this new technology is still little, except the promotion of some institutions like FAPESP, CAPES, CNPq and universities. This government leaves no room for short-term responses to new demands for power resulting in filling other types of no clean energy clean and fuels such as increasing the thermal power plants.