Dissertations / Theses on the topic 'Inductance variable'

Suite à la demande de miniaturisation des composants passifs, qui occupent la plus grande partie de la surface des cartes de radiocommunication des téléphones mobiles, certaines équipes de recherche se sont intéressées à l'intégration de ces composants passifs, à valeur fixe, dans les applications RF. La recherche concernant les micro-composants commandables reste quant à elle très discrète et cela malgré le marché potentiel que représentent les futurs systèmes de communication. Les travaux présentés dans cette thèse de doctorat apportent une réponse à la conception et à la réalisation de micro-inductances variables de type MEMS. Les premiers chapitres se focalisent sur l'étude de faisabilité de ces composants, leur dimensionnement et les étapes technologiques de micro-usinage nécessaires à leur réalisation. La solution retenue pour la réalisation des inductances variables, basée sur les variations du coefficient de couplage entre circuits, permet d'obtenir des variations importantes, et continues, d'inductance sur une large bande de fréquence. Le modèle électrique proposé, associé à ce composant, a été validé par les différentes mesures effectuées. Le dernier chapitre présente des exemples de co-intégration de capacités et d'inductances variables au sein d'une fonction accordable. Les mesures effectuées sur ces dispositifs permettent de valider le principe d'une fonction hyperfréquence réalisée uniquement à partir de composants passifs variables de type MEMS. Les différents démonstrateurs réalisés possèdent peu d'exemples équivalents connus à ce jour<br>Due to the increasing need of very small passive component chips, which represent a large surface on the cell phone electronic board, many laboratories try to integrate these passive components, with constant electric characteristics, into RF application chips. The research on tunable micro-components is still insignificant, despite the important market the future communication systems can represent. The study presented in this Ph. D. Report gives a concrete response to the conception and realization of tunable MEMS inductors. The first chapters focus on the feasibility of such components, and describe their design and fabrication process flow. The solution used to realize tunable MEMS inductors is based on magnetic coupling variations, between electric circuits, produced by mechanical displacements. Such a method gives large and continuous inductor variation ratios. The electric model proposed for this tunable micro-inductor has been validated by measurements. The last chapter gives some examples of tunable RF functions realized using tunable MEMS inductors and tunable MEMS capacitors. Measurements performed on these demonstrators validate the feasibility of tunable RF functions with continuous variation ratios

Depuis une bonne dizaine d'année, l'aéronautique a entamé sa mutation vers le "plus électrique".L'objectif étant de réduire la consommation de carburant, une des contraintes majeures de ces nouvelles solutions est de réduire la masse embarquée. Les filtres dimensionnés pour les convertisseurs statiques doivent donc être optimisés au mieux vis-à-vis de ce critère, ainsi que du volume. Il y a donc un fort besoin du côté des concepteurs d’avions de savoir quels choix parmi les différentes possibilités technologiques sont optimaux, et de connaître l'impact de ces choix sur le poids, le coût global et le volume de l'équipement. Le filtre CEM représente généralement environ 30% du coût et du volume d'un convertisseur électronique de puissance. Il va de soi que le volume et/ou la masse de ces filtres doit être optimisé. L'impact de la loi de commande du convertisseur, le choix des semi-conducteurs, du packaging, câbles (longueur et intégration dans l’avion), des machines électriques,...doivent être parfaitement connus pour atteindre un dimensionnement optimal.Dans cette perspective, les objectifs de ces travaux de thèse visent à fournir non seulement une démarche méthodologique pour la modélisation haute fréquence des variateurs de vitesse dédiés aux applications aéronautiques mais aussi une approche de dimensionnement par optimisation des filtres CEM. Pour cela, un outil logiciel évolutif d’aide à la génération rapide des modèles CEM est proposé. Une description modulaire et une mise en équation automatique du modèle fréquentiel complet ainsi que des gradients en facilitent l'utilisation en procédures d’optimisation sous contraintes. L’approche présentée dans ces travaux est relativement générique : la topologie du filtre, de la structure du convertisseur, du câblage et la loi de commande peuvent être facilement recalculées, grâce à cet environnement logiciel<br>The More Electrical Aircraft concept is very promising regarding energy saves, but generates new problems, and especially the emergence of new power electronics loads on the electrical network. Keeping the same level of safety in the aircraft means developing these switching mode converters in accordance with the aircraft standards, as the DO160. This is not obvious since weights of equipments are especially constrained: indeed, the objective of weight and energy save needs to be balanced with the additional weight and volume of the required EMI filters. There is thus a strong need in helping the aircraft designers to choose among the various technological possibilities, and to know the impact of these choices on the global weight, cost and volume of the embedded equipments. The EMI filter usually represents roughly 30% of the cost and volume of a power electronics converter, and it is very important to optimize it. The impact of the converter control law, semiconductors choice, interconnects realization, harness selection and placement, electrical motors characteristics… should be perfectly known in order to reach a good system design. In this perspective, the objectives of this thesis are to provide not only an approach for modelling high frequency variable speed drives dedicated to aerospace applications but also a methodology to optimize the required EMI filters. For this purpose, new architecture software dedicated to the rapid generation of EMC models is proposed. A modular description and a complete automatic model generation facilitate the use by the designer in optimization procedures thanks to automatic gradient computation.The methodology presented in this work is not specifically developed for a given application. It is a very generic approach: the topology of the filter, the structure of the inverters, interconnects and the control law can be easily recalculated, using this software environment. Consequently, the impact of all these elements on the electromagnetic disturbances can be characterized, and the EMI filter optimized

Les systèmes de communication mobiles permettent l’utilisation de l’information en environnements complexes grâce à des dispositifs portables qui ont comme principale restriction la durée de leurs batteries. Des nombreux efforts se sont focalisés sur la réduction de la consommation d’énergie des circuits électroniques de ces systèmes, une fois que le développent des technologies des batteries ne avance pas au rythme nécessaire. En outre, les systèmes RF sont généralement conçus pour fonctionner de manière fixe, spécifiés pour le pire cas du lien de communication. Toutefois, ce scénario peut se produire dans une petite partie du temps, entraînant ainsi en perte d’énergie dans le reste du temps. La recherche des circuits RF adaptatifs, pour adapter le niveau du signal d'entrée pour réduire la consommation d'énergie est donc d'un grand intérêt et de l'importance. Dans la chaîne de réception radiofréquence, l'amplificateur à faible bruit (LNA) se montre un composant essentiel, autant pour les performances de la chaîne que pour la consommation d'énergie. Au cours des dernières décennies, des techniques pour la conception de LNAs reconfigurables ont été proposées et mises en oeuvre. Cependant, la plupart d'entre elles s’applique seulement au contrôle du gain, sans exploiter Le réglage de la linéarité et du bruit envisageant l'économie d'énergie. De plus,ces circuits occupent une grande surface de silicium, ce qui entraîne un coût élevé, ou NE correspondent pas aux nouvelles technologies CMOS à faible coût. L'objectif de cette étude est de démontrer la faisabilité et les avantages de l'utilisation d'un LNA reconfigurable numériquement dans une chaîne de réception radiofréquence, du point de vue de la consommation d'énergie et de coût de fabrication<br>Mobile communication systems allow exploring information in complex environments by means of portable devices, whose main restriction is battery life. Once battery development does not follow market expectations, several efforts have been made in order to reduce energy consumption of those systems. Furthermore, radio-frequency systems are generally designed to operate as fixed circuits, specified for RF link worst-case scenario. However, this scenario may occur in a small amount of time, leading to energy waste in the remaining periods. The research of adaptive radio-frequency circuits and systems, which can configure themselves in response to input signal level in order to reduce power consumption, is of interest and importance. In a RF receiver chain, Low Noise Amplifier (LNA) stand as critical elements, both on the chain performance or power consumption. In the past some techniques for reconfigurable LNA design were proposed and applied. Nevertheless, the majority of them are applied to gain control, ignoring the possibility of linearity and noise figure adjustment, in order to save power. In addition, those circuits consume great area, resulting in high production costs, or they do not scale well with CMOS. The goal of this work is demonstrate the feasibility and advantages in using a digitally controlled LNA in a receiver chain in order to save area and power<br>Os sistemas de comunicação móveis permitem a exploração da informação em ambientes complexos através dos dispositivos portáteis que possuem como principal restrição a duração de suas baterias. Como o desenvolvimento da tecnologia de baterias não ocorre na velocidade esperada pelo mercado, muitos esforços se voltam à redução do consumo de energia dos circuitos eletrônicos destes sistemas. Além disso, os sistemas de radiofrequência são em geral projetados para funcionarem de forma fixa, especificados para o cenário de pior caso do link de comunicação. No entanto, este cenário pode ocorrer em uma pequena porção de tempo, resultando assim no restante do tempo em desperdício de energia. A investigação de sistemas e circuitos de radiofrequência adaptativos, que se ajustem ao nível de sinal de entrada a fim de reduzir o consumo de energia é assim de grande interesse e importância. Dentro de cadeia de recepção de radiofrequência, os Amplificadores de Baixo Ruído (LNA) se destacam como elementos críticos, tanto para o desempenho da cadeia como para o consumo de potência. No passado algumas técnicas para o projeto de LNA reconfiguráveis foram propostas e aplicadas. Contudo, a maioria delas só se aplica ao controle do ganho, deixando de explorar o ajuste da linearidade e da figura de ruído com fins de economia de energia. Além disso, estes circuitos ocupam grande área de silício, resultando em alto custo, ou então não se adaptam as novas tecnologias CMOS de baixo custo. O objetivo deste trabalho é demonstrar a viabilidade e as vantagens do uso de um LNA digitalmente configurável em uma cadeia de recepção de radiofrequência do ponto de vista de custo e consumo de potência

碩士<br>國立交通大學<br>電控工程研究所<br>107<br>This thesis proposes an inductive accelerometer with digital output, which is fabricated by TSMC 1P6M 0.18μm CMOS MEMS process. In this design, the LC oscillator is composed of a variable spring-inductor which is connected with a high Q inductor in series and is paralleled with a MIM capacitor. When an external acceleration acts on the chip, displacement of the mass occurs and, at the same time, the spring-inductor area and inductance value change. The change of the inductance value causes the oscillation frequency changes. Furthermore, the changes of frequency and acceleration are in direct proportion. Therefore, the acceleration can be detected by the frequency change. In addition, a counter circuit is added in the chip. The oscillator output is connected to the counter for frequency counting which converts the frequency output to the digital output for subsequent measurement and application. The counter also avoids using the external instruments that may cause additional parasitic effects and affect sensor performance. In this thesis, the measurement result shows the oscillation frequency is 1.38 GHz and sensitivity is 37.8 kHz/g.

Dissertação de Mestrado Integrado em Engenharia Electrotécnica e de Computadores apresentada à Faculdade de Ciências e Tecnologia da Universidade de Coimbra<br>O carregamento de baterias é um conceito que faz parte do dia-a-dia de qualquer pessoa nos tempos que correm. Atualmente, é impensável para a grande maioria das pessoas, viver sem dispositivos que requerem energia elétrica armazenada, tal como o telemóvel ou o computador portátil. Mas não é só nestes dispositivos eletrónicos que o armazenamento de energia elétrica é importante. No sector dos transportes, os Veículos Elétricos (VE) são cada vez mais uma realidade. No entanto, enfrentam o problema do armazenamento de energia elétrica, que os impede de fazerem viagens de longa distância sem fazer paragens de longa duração, ao contrário de um veículo de combustão. O carregamento de baterias sem fio poderá ajudar a quebrar algumas barreiras, uma vez que o veículo não precisa da intervenção humana para carregar. Um autocarro citadino, por exemplo, quando faz paragens para troca de passageiros, pode aproveitar para carregar baterias de forma autónoma. Esta tecnologia, que permite a transferência de energia sem contacto, é denominada de transferência de energia por indução (IPT) e permite a troca de energia através de núcleos de ar com grandes distâncias. No entanto, para que tenham um bom funcionamento, é necessário um controlo rigoroso, de modo a obter bons rendimentos, preservar os materiais envolvidos no processo de carregamento e garantir a segurança das pessoas. Esta dissertação tem como objetivo avaliar o comportamento de uma bobina variável num sistema IPT, para o controlo da corrente de carga e compensação de eventuais desalinhamentos prejudiciais ao processo de carregamento do veículo. Inicialmente, é apresentada uma introdução teórica sobre sistemas IPT e o funcionamento de conversores ressonantes, já que estes conseguem aumentar o rendimento deste tipo de sistemas. Ainda na introdução, é descrito o funcionamento de indutâncias variáveis de modo a implementar uma bobina variável. De seguida, com o objetivo de validar os princípios estudados, recorre-se a uma simulação computacional, variando a bobina em três níveis de indutância diferentes, de modo a analisar o comportamento do sistema e os respetivos resultados, nomeadamente a corrente de carga na bateria. Por fim, o sistema é implementado em laboratório de modo a validar os resultados da simulação computacional para os três níveis de indutância. Adicionalmente, ainda em laboratório, são realizados ensaios para avaliar o desempenho da bobina na compensação de eventuais desalinhamentos. Após a análise dos diversos resultados, tanto computacionais, como práticos, conclui-se que o controlo através da bobina variável permite variar os níveis de corrente de carga, e aumentar o rendimento do sistema na ocorrência de desalinhamentos.<br>Battery charging is a common concept in everyday life of most people. Currently, it is unthinkable for the majority of people to live without devices requiring stored energy, such as, phones or laptops. The importance of electrical energy storage is wider than those electronic devices. In the transport sector, the Electric Vehicles are increasingly becoming a reality. However, they face the problem of electricity storage, which prevents them from making longdistance travel without long stops, unlike a combustion vehicle. Wireless battery charging can help overcoming some drawbacks, since the vehicle does not need any human intervention to charge. A city bus, for example, when stopping to exchange passengers can take advantages of the independent charging. The technology that allows contactless energy transfer, is called inductive power transfer and allows the exchange of energy through air gaps. Nevertheless, a close monitoring of those systems is essential to obtain good yields, preserve the materials involved in the loading process and ensure the safety of people. This work aims to evaluate the behavior of a variable inductor in an IPT system to control the charging current and compensate for any misalignment harmful to the vehicle charging process. Initially, it is presented a theoretical introduction to IPT systems and resonant converters, due to its role in increasing the efficiency of such systems. The introduction also includes a description of the operation of variable inductances in order to implement a variable inductor. Then, it is described the computational simulation, using three different inductance values in order to analyze the behavior of the system, focusing in the load current of the battery. Finally, the system implemented in the laboratory is explained aiming to validate the computational results for the three inductance levels. Additionally, using the same system, it is analyzed the performance of the inductor in compensation for any misalignment, by testing three different misalignments. After analyzing the results both, computational and practical, it can be concluded that the variable inductor is able to control the system through the variation of the load current and increases the system performance in case of misalignment.

Dissertação de Mestrado Integrado em Engenharia Electrotécnica e de Computadores apresentada à Faculdade de Ciências e Tecnologia<br>A bobina variável tem vindo a revelar-se um dispositivo de grande utilidade em diversos campos, sendo por isso um alvo de estudo recorrente em várias áreas.Este documento pretende analisar detalhadamente o comportamento eletromagnético de diversas configurações de núcleos da bobina variável por forma a aferir qual configuração melhor se adapta para futura integração num sistema de carregamento indutivo de veículos elétricos.A análise foi concretizada com recurso ao software de método de elementos finitos FLUX3D e através de testes de pequeno sinal.As diferentes configurações estudadas têm como denominador comum a utilização de um núcleo formado por duas ferrites de formato E e a utilização de dois tipos de enrolamento: o enrolamento principal e o enrolamento de controlo. O enrolamento de controlo é alimentado por uma fonte de corrente contínua permitindo, devido a uma série de fenómenos eletromagnéticos, variar a indutância medida no enrolamento principal.Concluída a análise eletromagnética de quatro configurações diferentes, foi aferida qual apresenta o comportamento eletromagnético que mais se adequa ao funcionamento como bobina variável. A configuração eleita foi adaptada por forma a cumprir os requisitos necessários para ser parte integrante do referido sistema de carregamento com topologias ressonantes.Após a modelação e análise do projeto resultante através do método de elementos finitos, foi concebido um protótipo da bobina variável e testado num circuito de teste RLC com ponte inversora.<br>The variable inductor has proven to be a device of great importance in various applications, hence being heavily studied in numerous scientific areas. The proposed dissertation focuses on the electromagnetic behavior of various configurations of the variable inductor's core, to determine which one best integrates an inductive charging system designed for electric vehicles. The analysis was carried out using FLUX3D, a finite element method software, and through small signal tests.The different configurations that were studied, all use a two E-shaped cores and two kinds of windings: the main winding and the control winding. The control winding is fed by a DC power supply allowing to vary the main winding’s inductance, due to a series of electromagnetic phenomena. Four different configurations were tested, and the one whose electromagnetic behavior best suited the of the variable inductor was chosen. The selected configuration was chosen to fulfil the necessary requirements to properly integrate the charging system at hand, with resonant topologies.Lastly, after modelling and analyzing the resulting project using the finite element method, a variable inductor prototype was built and tested in a RLC test circuit with a inverter bridge.

碩士<br>國立交通大學<br>電子工程系所<br>95<br>In At this paper, thermal annealing effect on the inductor performance has been investigated. 30 mins. 600�aC thermal annealing performed to have ~7.4% electrical resistivity reduction of Cu film won’t result in any inductance variance of on-chip spiral inductor that made of the same Cu. For a total of 18 3.5-circles on-chip spiral inductors, the inductance variance before and after the thermal anneal only ranges from -2.25% to 0.41%. Meanwhile, the resonant frequency associated with the inductance variance also changes from -8.22% to 1.68%. According to hypothesis test statistical method, it shows that these variances are not correlated which can be attributed to experimental variation and there is, in fact, no thermal annealing effect on the inductor performance. The results also indicate that the electrical conductivity is independent of the inductance of on-chip spiral inductor which is matched with the prediction of Greenhouse model but totally contradicts with the model proposed by Chen et al..

Ce travail concerne les machines synchrones à excitation (rotor bobiné). Leur modélisation est effectuée sous forme analytique; elle peut être employée lors des phases d'étude et de conception de ces machines (par exemple, pour la prédétermination des formes d'ondes et des pertes fer). Le premier chapitre présente les véhicules électriques et les particularités de leur chaîne de traction. Nous en déduisons ensuite les contraintes qui influent sur les paramètres magnétiques de ces machines. La méthode de calcul utilisée est détaillée dans le deuxième chapitre. Celle-ci permet d'analyser les effets de la saillance des machines au cours de leur rotation. Cette méthode se base sur une étude de la perméance d'entrefer (unique point traité par résolution numérique) qui conduit à un modèle de cette zone soit ponctuel, soit harmonique. Nous présentons ensuite les éléments permettant d'adapter cette caractérisation au cas des machines synchrones à aimants permanents. Les chapitres suivants sont consacrés à l'exploitation et à la validation de ce modèle pour différents points de fonctionnement de la machine. Le calcul des inductances (directe et en quadrature) en régime permanent, ainsi que la détermination de la répartition instantanée des flux en rotation, y sont traités. Les résultats obtenus avec le modèle analytique sont comparés à ceux obtenus avec des résolutions intégralement numériques (éléments finis). Divers cas ont été testés, notamment le fonctionnement en survitesse avec une forte réaction d'induit et le fonctionnement à couple maximum. Le modèle a permis de reconstituer avec une bonne précision ces différents cas, même en présence de saturation. Ces résultats valident le concept développé ici.