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Trabalho de conclusão de curso (graduação) - Universidade Federal de Santa Maria, Centro de Tecnologia, Curso de Engenharia de Controle e Automação, RS, 2016. ; This work aims to development a vibration measurement system providing the measurements performed on a microSD memory card. This system is isolated from the electricity network. The system consists of a concerto microcontroller, an interface printed circuit board (PCB), two photovoltaic panels, two batteries, a charge controller and four ICP® accelerometers. The microcontroller is the brain of the acquisition system, responsible for processing the information and write to the external memory. The interface PCB is designed to connect the microcontroller to the accelerometers and the charge controller. The photovoltaic panels, the battery and the load controller are the generation and storage system, supplying energy for the system. In order to validate the developed system, tests were performed using vibrations of known frequency and intensity. ; O presente trabalho tem como objetivo desenvolver um sistema de medição de vibrações, isolado da rede de energia elétrica, disponibilizando em um cartão de memória micro SD as medições realizadas. O sistema é composto de um microcontrolador concerto, uma placa de interface, dois painéis fotovoltaicos, duas baterias, um controlador de carga e quatro acelerômetros ICP. O microcontrolador é o cérebro do sistema de aquisição, responsável pelo processamento das informações e gravação na memória externa. A placa de interface foi desenvolvida para interligar o microcontrolador aos acelerômetros e ao controlador de carga. Os painéis fotovoltaicos, as baterias e o controlador de carga são o sistema de geração e armazenamento de energia, fornecendo energia para o funcionamento do sistema. Com a intenção de validar o sistema desenvolvido, foram realizados testes utilizando vibrações com intensidade e frequência conhecidas.

In the research work carried out under this thesis it is investigated the possibility of combining the passive vibration control and the generation of electricity from the vibratory motion. In this context, the central aim of the thesis is the development, including design, numerical and experimental evaluation devices for simultaneous performance as piezoelectric energy generators (PEH) and dynamic vibration absorbers (DVA), called PEH/DVA. In order to consider practical situations in which a device of this type must be connected to a vibrating structure called primary structure (PS), the study has emphasized the characterization of dynamic interactions between EP and PEG/DVA, since these interactions determine the efficiency of PEH/DVA in terms of vibration control and power generation. A general structural formulation was developed containing piezoelectric transducers connected to resistors in which both the PEH/DVA and PS were considered continuous vibratory subsystems discretized with various degrees of freedom. In the numerical simulations performed using computer codes implemented in MATLAB® environment, these two subsystems were modeled as beams of Euler-Bernoulli. The simulations were aimed, first, to the characterization of the dynamic interactions between the two subsystems, and subsequently, the optimization of PEH/DVA with towards to maximize its functionality. For the experimental study a new configuration of PEH/DVA called cruciform (PEH/DVA-C) prototype was designed, constructed and experimentally tested. It was built using four aluminum blades in the balance sheet, arranged in a cross, and the surface of each blade a ceramic piezoelectric transducer has been glued. The four transducers were connected electrically in series, such a way that when the blades undergo deflection, the electrical voltages produced by the transducers are summed. Concentrated masses at the free ends of the blades were added to increase the level of vibration and to facilitate the adjustment of the natural frequencies of ...

In response to an ever increasing demand for electricity and the desire for environmentally friendly energy sources, new policies have emerged to produce "green" energy from renewable sources. Many of the initial investments were made in wind energy, solar energy, biomass energy, geothermal energy, among others, that allow a little pollution or in certain cases no pollution at all. Although human power is not enough to sustain a massive power grid, it has the potential to charge electronic devices such as iPod's, music players and mobile phones. The process of energy harvesting consists of using environmental energy to supply primarily (but not exclusively) electricity to small mobile devices, either electrical or electronic. This process should be free of maintenance and have a high durability, reducing the need for batteries. The human movement is characterized by movements of large amplitude at low frequencies and some level of impact in the area of the foot heel during walking. These impacts send shock waves through the human body which are rapidly absorbed by the articulations. Studies have demonstrated that, on average, an individual with 68 kg walking at a speed of 2 steps per second and with a vertical movement of the heel of 5 cm is capable of generating 67 W of energy [1]. The transducers energy devices can be placed in different locations of the human body, may be in clothing, shoes, a waist bag, a backpack, among others. Nevertheless, the amplitude, frequency and nature of the vibration can be quite different in different locations of the body. There are several types of generators that allow capture and transform the human motion into electrical energy such as inertial, piezoelectric, electrostatic and electromagnetic generators. There are several types of generators that allow to capture and transform the human motion into electrical energy such as inertial, piezoelectric, electrostatic and electromagnetic generators. In this project it was decided to use the electromagnetic generator because it is the one that best adapts to the capture of human movement and the vibration of the same. Furthermore, it is the most efficient, because humans’ movements cause a variation in the magnetic field of an inductor, which in turn will produce a current. The problem that this project proposes to solve consists in designing a system to capture energy generated by human activity in order to detect, capture and convert (specifically walking or running) the human motion into electricity which can be used as and provide a portable power source. In the end of this project, it is concluded that the energy captured through human action and transformed into renewable energy is viable presenting, however, very low power values produced. Em resposta ao aumento da procura de eletricidade e ao desejo de fontes energéticas ambientalmente amigáveis, têm surgido novas políticas de produzir energia “verde” de uma forma rentável a partir de fontes de energia renováveis. Muitos dos investimentos iniciais foram realizados em energia eólica, energia solar, energia de biomassa, energia geotérmica, entre outras, que permitem pouca ou nenhuma poluição. Embora a energia humana não seja suficiente para sustentar uma rede elétrica massiva, tem potencial para carregar dispositivos eletrónicos como iPod’s, leitores de música e telefones móveis. O processo de captação de energia consiste em usar a energia ambiental para fornecer primariamente (mas não exclusivamente) eletricidade a pequenos dispositivos móveis, sejam esses elétricos ou eletrónicos. Este processo deverá ser isento de manutenções e possuir uma durabilidade elevada, reduzindo assim a necessidade de baterias. O movimento humano é caracterizado por movimentos de grande amplitude a baixas frequências e algum grau de impacto na zona do calcanhar do pé durante uma caminhada. Estes impactos enviam ondas de choque através do corpo humano sendo rapidamente absorvidos pelas articulações. Estudos demonstraram que, em média, um indivíduo de 68 kg que caminha à velocidade de 2 passos por segundo e com um movimento vertical de calcanhar de 5 cm é capaz de gerar 67 W de energia [1]. Os dispositivos transdutores de energia podem ser colocados em diferentes locais do corpo humano seja no vestuário, no calçado, numa bolsa de cintura, numa mochila, entre outros. Porém a amplitude, a frequência e a natureza da vibração podem ser bastante diferentes em locais do corpo distintos. Existem vários tipos de geradores que permitem captar e transformar o movimento humano em energia elétrica tais como os geradores inerciais, piezoelétricos, eletrostáticos e eletromagnéticos. Neste projeto optou-se por utilizar o gerador eletromagnético pois é o que mais se adapta à captação dos movimentos humanos e vibração dos mesmos, também porque é o mais eficiente visto que o ser humano ao movimentar-se provoca uma variação no campo magnético da bobina que por sua vez produzirá uma corrente. Este projeto apenas incidirá na captação de energia a partir de fontes vibracionais. Isto não significa que as fontes de energia vibracionais são a melhor opção na captação energética, mas apenas uma das soluções mais apropriadas para a autossustentabilidade e miniaturização de pequenos dispositivos. Terminado este projeto, conclui-se que a energia captada através da ação humana e transformada em energia elétrica renovável é viável apresentando, contudo, valores de potência produzida muito baixos. Dissertação de mestrado integrado em Engenharia Eletrónica Industrial e Computadores

Energy harvesting from environmental sources is a promising technique with great potential that can contribute to the generation of clean electric energy from renewable sources, suitable for the operation of self-powered, low-power electronic devices. In this sense, this work aims to develop and evaluate the performance of a device that transforms mechanical vibrations present in the environment into electric energy using Lead Zirconium Titanate (PZT) piezoelectric ceramics. The generator was constructed as a mechanical structure capable of providing cyclic deformations to eight piezoelectric cells, through tensile/compressive loads. Prior to the construction of the device, its geometric dimensions were established through a finite element analysis. For the acquisition of the experimental results a duly instrumented measurement system was used, where it was possible to obtain data regarding the acceleration, voltage and electric power generated by the device. The results from numerical and experimental analyses - related to the dynamics of the device and the generated electric voltage, are presented and compared. The generator was evaluated for different vibration amplitudes and generated a maximum power of 9.6 mW when operating at its first natural frequency (60 Hz), considering a resistive load of 15 kΩ. Finally, the performance of the generator was evaluated under two different ambient excitation conditions, when coupled to an air condition condenser and when coupled to a three phase induction motor. ; Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq ; A colheita de energia presente no ambiente é uma técnica promissora e de grande potencial que pode contribuir com a geração de energia elétrica, de forma limpa, a partir de fontes renováveis, viabilizando o funcionamento de dispositivos eletrônicos de baixa potência autoalimentados. Neste sentido, este trabalho tem como objetivo o desenvolvimento e a avalição do desempenho de um dispositivo que transforma as vibrações mecânicas ...

In this dissertation we present the main results about the magnetic properties of elastic ferromagnets based on the analysis of different behaviours of the exchange parameter O (or exchange interaction). Firstly, we analyzed the variation of exchange parameter O with H and T , i.e., O vH w , O vT w and O vH,T w , obtaining an additional contribution whitout defined physically origin, vH,T w adic { ´S , which when added to the conventional entropy, conv { ´S , results in the variation of total entropy, total { ´S , obtained by Maxwell¡¦s relation. In what follows, we implement a model that includes a vibrational energy in the Einstein approximation for high temperatures, and an other with a quadratic dependence of the isothermal compressibility with the temperature by means of the relation 2 o T K ­ K y a T , so that obtain an additional contribution with defined physically origin. These additional contributions are obtained by magnetoelastic coupling to rewrite the system in terms of the exchange parameter O x that when applied to the model entropy exchange (proposal by Plaza-Campoy), leads to additional contributions to the { ´S eT curves. In a third approximation, we formulate the O parameter within the RKKY fenomenology, Ë Í o RKKY O ­ O J ç , and analyse the magnetic properties (magnetization, exchange parameter, deformation, magnetic entropy, etc.) for different regions of the RKKY curve. In this fenomenology, the exchange parameter varies in a non linear form as a function of the deformation, although when we get closer to a linear region we verified that the Bean- Rodbell model approximates well the RKKY model. Finally, we start from a generalized exchange Hamiltonian and formulate an generalized exchange energy that inserted in the Gibbs free energy, promotes an additional contribution to the magnetic properties, showing up the importance of the v1 4 w factor in the exchange hamiltonian when the exchange parameter depends on the interatomic distances. ; Nesta dissertacao sao apresentados os principais ...