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Sistemas de transferência de energia sem fio em campo próximo (NF-WPT, NearField Wireless Power Transfer) tem atraído atenção por suas potenciais aplicações, tais como, dispositivos médicos implantados (IMDs), identificação por rádio frequência (RFID, Radio Frequency Identification) e dispositivos eletrônicos portáteis em geral. Nesse contexto, são propostos modelos compactos para sistemas NF-WPT de curto alcance operando em faixas de frequências ISM empregando o conceito de ressonadores de abertura no plano de terra (DGS, Defected Ground Structure). Essa técnica permite a miniaturiza- ção do ressonador, o que leva ao desenvolvimento de sistemas compactos de NF-WPT. O primeiro modelo proposto neste trabalho, visa possíveis aplicações que requerem transferência de energia e dados simultaneamente. Esse modelo opera em banda dupla nas faixas de frequências de 433 MHz e 900 MHz e faz o uso de DGS circulares sobrepostas a fim de compactar o dispositivo ressonador e obter altos valores de figura de mérito (FoM) comumente empregadas na área de pesquisa. Dessa forma, busca-se contribuir para o avanço do estado da arte dos sistemas WPT baseados em DGS de banda dupla. O segundo modelo proposto visa manter o conceito de compactação dos ressonadores mesmo em faixas de frequências mais baixas. São apresentados o desenvolvimento, construção e medição dos sistemas de WPT usando dispositivos ressonantes baseados em DGS projetados para as faixas de frequências ISM de 6,78 MHz, 27,12 MHz e 40,68 MHz. Ambos os modelos propostos são projetados utilizando o software de análise eletromagnética (EM) Ansys Electronics e são construídos utilizando o material dielétrico Rogers RO4003. Os ressonadores DGS de banda dupla projetados possuem uma área total de 11,7 x 10,2 mm2 e ao serem posicionados a uma distância de 15 mm entre transmissor e receptor apresentam valores de FoM medidas de 0,71 e 1,07 em 440 MHz e 918 MHz, respectivamente. Dois sistemas de banda única foram projetados usando o mesmo dispositivo DGS com dimensões de 13 x 14 mm2 e apresentaram FoM medidas de 0,65 e 0,75, a uma distância de 20 mm, respectivamente, para as frequências de 27,25 MHz e 40,25 MHz. Já o sistema projetado na faixa de frequência de 6,78 MHz, apresentou uma FoM de 0,48 a uma distância de 35 mm usando dispositivos com dimensões de 32 x 35,5 mm2. Os resultados são comparados com trabalhos relacionados encontrados na literatura. Near-field wireless power transfer systems (NF-WPT) have been attracting attention for their potential applications such as implantable medical devices (IMDs), radio frequency identification (RFID) and portable electronic devices. In this context, compact models are proposed for NF-WPT systems in industrial, scientific and medical (ISM) bands employing the concept of defected ground structure (DGS) resonators. This technique allows the miniaturization of the resonator, which leads to the development of compact NF-WPT systems. The first model that is proposed in this work aims at possible applications that require energy and data transfer simultaneously. It operates in dual band in the frequency bands of 433 MHz and 900 MHz and uses circulars superimposed DGS in order to compact the resonator device and obtain high values of figure of merit (FoM), commonly employed in the search area. In this way, the aim is to contribute to the advancement of the state of the art of WPT systems based on dual-band DGS. The second model proposed aims to maintain the concept of resonator compaction even in lower frequency bands. Three projects are presented in detail from the design to the construction and measurement of WPT systems using resonant devices based on DGS designed in the frequency bands of 6.78 MHz, 27.12 MHz and 40.68 MHz. Both models for proposed NF-WPT systems are designed using the Ansys Electronics electromagnetic analysis software and are built using Rogers RO4003 dielectric material. Dual-band DGS resonators have a total area of 11.7 x 10.2 mm2 and an optimal WPT distance of 15 mm between transmitter and receiver. At this distance, the FoMs are measured and presented 0.71 and 1.07 at 440 MHz and 918 MHz, respectively. Two single-band systems are designed using the same DGS device with dimensions of 13 x 14 mm2 and presented FoM measures of 0.65 and 0.75, at a distance of 20 mm, respectively, for the frequencies of 27.25 MHz and 40.25 MHz. The system, designed in the frequency range of 6.78 MHz, presented a FoM of 0.48 at an optimized 35 mm WPT distance using devices with dimensions of 32 x 35.5 mm2. The results are discussed and compared with related works found in the literature.

Este trabalho apresenta uma revisão de artigos sobre aplicações de transferência de energia sem fio multibobinas para alimentação de dispositivos médicos implantáveis nos últimos dez anos. Para o levantamento destes artigos, diversas bases de dados foram utilizadas a fim de proporcionar uma consulta mais variada para a coleta dos dados. Uma tabela de comparação foi construída com os dados extraídos dos artigos analisados, assim como dois gráficos para mapeamento das aplicações mais efetivas. Os resultados desta tabela são utilizados para realizar comparações entre as diferentes abordagens utilizadas e para identificar os parâmetros e tecnologias que têm apresentado melhores resultados. Estas comparações podem ser utilizadas para auxiliar na definição de novos trabalhos a serem desenvolvidos. Os resultados obtidos demonstram que a frequência de 13,56 MHz foi a mais utilizada, e a distância mais utilizada está na faixa dos 10 mm. Já a melhor eficiência encontrada foi de 82,4%., XII SIMPÓSIO DE ENGENHARIA BIOMÉDICA - IX SIMPÓSIO DE INSTRUMENTAÇÃO E IMAGENS MÉDICAS

Wireless power transmission has been recently used to charge batteries in portable devices. This is the first study to combine this technology with light-emitting diodes (WPT-LP) for plant tissue culture application. We also present the comparison of the in vitro growth of chrysanthemum and strawberry plantlets under the new LED lighting system; LED - Uni-Pack (LP) system; LED tube and fluorescent light (FL). The results showed that fresh weight (1.42 g), dry weight (118.67 mg), plant height (5.68 cm), leaf area (3.59 cm2) and chlorophyll content (47.9 μg g-1) of chrysanthemum plantlets under the WPT-LP system were higher than those under FL and LED tube. Similar results were also recorded on the strawberry plantlets. Our results suggested that utilizing WPT-LP system saves the culture space considerably compared with the conventional downward lighting system with fluorescent lamps. The results also indicated that the subsequent growth and development of chrysanthemum and strawberry plantlets derived from WPT-LP system were either equal to or better than those from LP system under LED tube or FL. RESUMO A transmissão de energia sem fio tem sido usada recentemente para carregar baterias em dispositivos portáteis. Este estudo é o primeiro a combinar essa tecnologia com diodos emissores de luz (WPT-LP) para aplicação em cultura de tecido vegetal. Também são apresentadas comparações entre crescimento in vitro de plântulas de crisântemo e morango com o novo sistema de iluminação: sistema LED - Uni-Pack (LP), tubo LED e luz fluorescente (FL). Os resultados demonstraram que peso fresco (1,42 g), peso seco (118,67 mg), altura da planta (5,68 cm), área foliar (3,59 cm2) e conteúdo de clorofila (47,9 g g-1) de plântulas de crisântemo submetidas ao sistema WPT-LP foram maiores do que os daquelas submetidas a FL e tubo LED. Resultados similares também foram registrados em plântulas de morango. Esses resultados sugerem que, usando-se o sistema WPT-LP, tem-se uma economia de espaço de cultura considerável em comparação ao sistema convencional de iluminação descendente com lâmpadas fluorescentes. Os resultados também indicaram que o crescimento subsequente ao desenvolvimento de plântulas de crisântemo e morango provenientes do sistema WPT-LP foi igual e/ou melhor que o daquelas oriundas dos sistemas LP e tubo LED ou FL.

A transferência de energia sem fios tem sido utilizada para alimentação de dispositivos e sistemas remotos, em que o uso de fiosé inadequado, custoso ou até mesmo proibitivo. As suas aplicações abrangem desde dispositivos biomédicos implantáveis, passando pelo setor de eletrônicos de consumo, até recarga de baterias em veículos elétricos. A potência transferida à carga depende dos parâmetros do circuito equivalente, entre os quais, o coeficiente de acoplamento magnético e o valor da carga desempenham um papel importante. O desalinhamento entre as bobinas transmissora e receptora, bem como as condições de carga variável, tornam o problema de maximização da energia transferida não trivial, pois a função objetivo muda de acordo com os parâmetros do circuito equivalente, causando um decréscimo significativo na potência da carga fora das condições iniciais de projeto. Portanto, maximizar a potência transmitida à cargaé um problema pertinente em todas as aplicações. Neste trabalho, são apresentadas contribuições para a metodologia de projeto de acoplamentos indutivos compensados, em que os diâmetros de bobinas planares circulares são escolhidos de forma a maximizar o coeficiente de acoplamento magnético. Além disto, e apresentado um circuito eletrônico capaz de emular um capacitor controlado por tensão, cuja aplicação é realizada na rede capacitiva de compensação no lado primário do acoplamento indutivo. Pela medida da impedância de entrada do circuito é possível estimar a potência na carga e assim maximizá-la através do ajuste da capacitância da rede de compensação. A partir do estudo de caso apresentado, um aumento de 67% na potência fornecida à carga e conseguido em comparação a um acoplamento magnético com rede de compensação fixa. Por fim, e apresentada a maximização da potância entregueà carga utilizando não somente a capacitância de compensação variável, mas também a frequência de operação variável. Com a metodologia proposta, é possível manter a potência dissipada na carga aproximandamente constante para uma faixa de coeficiente de acoplamento magnético de 0,2 a 0,8 e carga de 10Ω a 100Ω, permitindo assim aumentar o grau de liberdade de posicionamento entre as bobinas transmissora e receptora. Wireless power transfer has been used for powering devices and systems remotely, where using wires is inadequate, costly, or even prohibitive. Its applications range from implantable biomedical devices, consumer electronics to battery recharging in electric vehicles. The power transferred to the load depends on the parameters of the equivalent circuit, which the magnetic coupling coe cient and the load value play an important role. The misalignment between the transmitter and receiver coils as well as the variable load condition make the transferred energy maximization problem non-trivial because the objective function changes according to the parameters of the equivalent circuit, causing a signi cant decrease in the load power as long as the parameters deviate from the initial design values. Therefore, maximizing the power transferred to the load is a relevant problem in all applications. In this work, contributions are presented to the design methodology of compensated inductive couplings, where the diameters of circular planar coils are chosen in order to maximize the magnetic coupling coe cient. In addition, an electronic circuit capable of emulating a voltage controlled capacitor is presented, whose application is carried out in the capacitive compensation network on the primary side of the inductive coupling. By measuring the input impedance of the circuit it is possible to estimate the power in the load and thus to maximize it by adjusting the capacitance of the compensation network. From the case study presented, a 67% increase in power dissipated in the load is achieved in comparison to a magnetic coupling with xed compensation network. Finally, the maximization of power delivered to the load is presented using not only the variable compensation capacitance, but also the variable operating frequency. With the proposed methodology, it is possible to keep the load power approximately constant for a range of magnetic coupling coe cient of 0:2 to 0:8 and load of 10Ω to 100Ω , thus increasing the degree of freedom of positioning between the transmitter and receiver coils.

Dissertação de Mestrado Integrado em Engenharia Electrotécnica e de Computadores apresentada à Faculdade de Ciências e Tecnologia Wireless power transfer technology has been widely used in many areas. This thesis implements a wireless charging system for consumer electronics for mobile applications such as laptops and tablets. The working on a wireless power transfer system is comparable to that of an air core transformer with the leakage compensated by means of capacitances. Compensation has been applied to both the primary and secondary of the transformer. This would help boost power transfer. Theoretically described the basic series-series compensation topology used. The resonant wireless power transfer is demonstrated in this thesis. The efficiency of such a system is analyzed and the results are promising, however, there are significant opportunities for improvement.This thesis consists of five chapters:chapter 1 is talking about the history, classification and applications of wireless power transfer. Chapter 2 is talking about Introduction about the fundamentals of wireless power transfer system, the theoretical study of the compensation topology and determines the important elements of such a system to help the design of a wireless power transfer system to be good.Chapter 3 Defines the parameters of the desired design by using Matlab codes and Matlab model simulation and comparison for the results.Chapter 4 Implement the study of the experimental system, and compare the result with its own simulated and calculated results.Chapter 5 at the end, we will see the conclusion of the project and the future work.Wireless power transfer technology has been widely used in many areas. This thesis implements a wireless charging system for consumer electronics for mobile applications such as laptops and tablets. The working on a wireless power transfer system is comparable to that of an air core transformer with the leakage compensated by means of capacitances. Compensation has been applied to both the primary and secondary of the transformer. This would help boost power transfer. Theoretically described the basic series-series compensation topology used. The resonant wireless power transfer is demonstrated in this thesis. The efficiency of such a system is analyzed and the results are promising, however, there are significant opportunities for improvement.This thesis consists of five chapters:chapter 1 is talking about the history, classification and applications of wireless power transfer. Chapter 2 is talking about Introduction about the fundamentals of wireless power transfer system, the theoretical study of the compensation topology and determines the important elements of such a system to help the design of a wireless power transfer system to be good.Chapter 3 Defines the parameters of the desired design by using Matlab codes and Matlab model simulation and comparison for the results.Chapter 4 Implement the study of the experimental system, and compare the result with its own simulated and calculated results.Chapter 5 at the end, we will see the conclusion of the project and the future work. Wireless power transfer technology has been widely used in many areas. This thesis implements a wireless charging system for consumer electronics for mobile applications such as laptops and tablets. The working on a wireless power transfer system is comparable to that of an air core transformer with the leakage compensated by means of capacitances. Compensation has been applied to both the primary and secondary of the transformer. This would help boost power transfer. Theoretically described the basic series-series compensation topology used. The resonant wireless power transfer is demonstrated in this thesis. The efficiency of such a system is analyzed and the results are promising, however, there are significant opportunities for improvement.This thesis consists of five chapters:chapter 1 is talking about the history, classification and applications of wireless power transfer. Chapter 2 is talking about Introduction about the fundamentals of wireless power transfer system, the theoretical study of the compensation topology and determines the important elements of such a system to help the design of a wireless power transfer system to be good.Chapter 3 Defines the parameters of the desired design by using Matlab codes and Matlab model simulation and comparison for the results.Chapter 4 Implement the study of the experimental system, and compare the result with its own simulated and calculated results.Chapter 5 at the end, we will see the conclusion of the project and the future work.Wireless power transfer technology has been widely used in many areas. This thesis implements a wireless charging system for consumer electronics for mobile applications such as laptops and tablets. The working on a wireless power transfer system is comparable to that of an air core transformer with the leakage compensated by means of capacitances. Compensation has been applied to both the primary and secondary of the transformer. This would help boost power transfer. Theoretically described the basic series-series compensation topology used. The resonant wireless power transfer is demonstrated in this thesis. The efficiency of such a system is analyzed and the results are promising, however, there are significant opportunities for improvement.This thesis consists of five chapters:chapter 1 is talking about the history, classification and applications of wireless power transfer. Chapter 2 is talking about Introduction about the fundamentals of wireless power transfer system, the theoretical study of the compensation topology and determines the important elements of such a system to help the design of a wireless power transfer system to be good.Chapter 3 Defines the parameters of the desired design by using Matlab codes and Matlab model simulation and comparison for the results.Chapter 4 Implement the study of the experimental system, and compare the result with its own simulated and calculated results.Chapter 5 at the end, we will see the conclusion of the project and the future work.