A promising method for charging batteries of electric vehicles (EV) is inductive power transfer (IPT), also known as inductive charging. IPT, a convenient, safe, and aesthetic method of charging EVs, inductively transfers high-frequency AC power in the transmitting pad, or coil, to the receiving pad, or coil. However, the application of IPT entails several practical limitations. For example, misalignment of the coils and varied charging distance (air gap) between the coils change the magnetic coupling effect between the transmitting and receiving coils. As a result, system stability decreases because the electrical characteristics in different charging cycles vary. Previous research has rarely proposed an adaptive and effective method to solve the problems of varied coupling. Many EV models, however, exist on the market and more will be released in the future. A universal charger suitable for charging various models of EVs will have broad applications, especially in public charging areas. Therefore, we must design a universal inductive charger capable of providing stable charging voltage to various loads, even with influences by varied magnetic coupling. Also important is the design standard of on-board chargers used for universal inductive charging. The design schemes of the universal inductive charger and on-board chargers can be used as references for the future development of the entire EV inductive charging system.

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Nous nous intéressons dans ce travail au prolongement d'applications linéaires, que ce soit des fonctions à valeurs scalaires ou des applications à valeurs opérateurs, sur des limites inductives d'espaces vectoriels topologiques en général et en particulier sur des algèbres d'opérateurs. Dans un premier lieu, nous regardons le problème dans le cadre le plus général c'est à dire celui de prolonger des formes linéaires sur une limite inductive d'espaces localement convexes. Nous donnons une condition nécessaire sur ces formes pour que le prolongement soit possible. Nous nous intéressons aussi au prolongement préservant la norme et nous donnons un exemple ou un tel prolongement n'est pas possible. Ensuite nous donnons une application de notre résultat principal dans le cadre des germes des fonctions holomorphes sur un compact de Cn. Puis nous généralisons les résultats obtenus dans le contexte des applications linéaires sur des C*-algèbres à valeurs opérateurs ce qui nous permet de généraliser l'application. En second lieu, nous considérons les mêmes questions dans le cas particulier de limites inductives: les espaces de fractions. Nous généralisons le résultat de F-H. Vasilescu dans le cas non commutatif ainsi que le problème des moments multidimensionnels sur un ensemble fermé non borné du corps des quaternion. En dernier lieu, nous nous intéressons aux applications complètement positives et complètement contractives à valeurs opérateurs sur des espaces de fractions. On considère le contexte non commutatif du papier de E. Albrecht et F -H. Vasilescu. Nous donnons un résultat pour chaque type de ses application linéaires. En applications aux résultats obtenues, on généralise notre problème des moments dans le cas opératoriel en introduisant une nouvelle mesure. Enfin, nous donnons une caractérisation des applications moments. / Ln this work we are interested by extending Iinear forms and Iinear maps in general on inductive Iimit spaces of locally convex spaces or of sorne operator algebras. Firstly, we consider the more general case i.e. extending linear forms on limit spaces of locally convex spaces. We give a necessary condition on the linear forms making the extension possible. We are also in interest of a norm preserving extension. We show by an example that a such extension is no always possible then we state our result in a general case. Moreover we give an application of our main result in a context of germes of holomorphic fonctions on a compact set of Cn. After that, we generalize this results and the application, by the same way, when the Iinear application are with operator values. Secondly, we consider the same questions in a particular case of inductive limits : The spaces of fractions. We generalize the result of F-H. Vasilescu in a non commutatif context and then we generalize the multi-dimensionnels moment problem on a closed unbounded set of quaternion set. Finally, we focus on the completely positive or completely contractive linear maps on spaces of fractions with operator values. We consider the non commutative context of the work of E. Albrecht and F-H. Vasilescu. As an application, we generalize the given moment problem on the operator case and we give a new measure. Then we give a characterization of the moment maps.

Tese de mestrado integrado. Engenharia Informática e Computação. Faculdade de Engenharia. Universidade do Porto. 2010

The overall goal of this work is to combine the complementary contributions of algebra and coalgebra to specification, in order to provide a formal framework for the specification of state-based, dynamical systems. Algebraic specification methods benefit from the availability of inductive techniques for defining and reasoning about structures that involve computation; coalgebraic specification methods complement algebraic ones both in their objectives and in their means of achieving them, by employing coinductive techniques for defining and reasoning about structures that involve observation. State-based, dynamical systems comprise a computational aspect, concerned with the construction of (new) system states, and an observational aspect, concerned with the observation of (existing) system states, with the two aspects overlapping on features concerned with the evolution of system states. Existing formalisms for the specification of such systems typically exploit the overlap between computational and observational features to employ either algebraic or coalgebraic techniques for specification and reasoning. However, such a choice limits the expressiveness of these formalisms w.r.t. either observational or computational features. Furthermore, the accounts given by such approaches to the concepts of indistinguishability by observations and respectively of reachability under computations are somewhat artificial, due to the failure to distinguish between computational and observational features. The approach taken here is to clearly separate the two categories of features (by shifting the features concerned with the evolution of system states to the computational component), and to use algebra and respectively coalgebra in formalising them. In particular, such an approach yields a coalgebraically-defined notion of indistinguishability by observations, and an algebraically-defined notion of reachability under computations. The relationship between computing new states and observing the resulting states is specified by suitably lifting the coalgebraic structure of the semantic domains induced by the observational component to computations over these semantic domains. Such an approach automatically results in a compatibility between computational and observational features, with the observational indistinguishability of states being preserved by computations, and with the reachability of states under computations being preserved by observations. Correctness properties of system behaviour are formalised using equational sentences. This is a standard technique in algebraic specification. A similar technique is used here for coalgebraic specification, with the resulting notion of sentence capturing system invariants quantified over state spaces. Moreover, a sound and complete calculus for reasoning about the specified behaviours is formulated in a concrete setting obtained by syntactically dualising the setting of many-sorted algebra. Equational sentences are then used to formalise the equivalence of computations as well as various system invariants, with the associated notions of satisfaction abstracting away observationally indistinguishable and respectively unreachable states, and with the associated proof techniques employing coinduction and respectively induction. Suitably instantiating the resulting approach yields a formalism for the specification and verification of objects.

La programmation par contraintes permet de modéliser des problèmes et offre des méthodes de résolution efficaces. Cependant, sa complexité augmentant ces dernières années, son utilisation, notamment pour modéliser des problèmes, est devenue limitée à des utilisateurs possédant une bonne expérience dans le domaine. Cette thèse s’inscrit dans un cadre visant à automatiser la modélisation. Les techniques existantes ont montré des résultats encourageants mais certaines exigences rendent leur utilisation encore problématique. Dans une première partie, nous proposons de dépasser une limite existante qui réside dans la nécessité pour l’utilisateur de fournir des solutions du problème qu’il veut modéliser. En remplacement, il nous fournit des solutions de problèmes proches, c’est-à-dire de problèmes dont la sémantique de fond est la même mais dont les variables et leur domaine peuvent changer. Pour exploiter de telles données, nous proposons d’acquérir, grâce à des techniques de programmation logique inductive, un modèle plus abstrait que le réseau de contraintes. Une fois appris, ce modèle est ensuite transformé pour correspondre au problème initial que souhaitait résoudre l’utilisateur. Nous montrons également que la phase d’apprentissage se heurte à des limites pathologiques et qui nous ont contraints à développer un nouvel algorithme pour synthétiser ces modèles abstraits. Dans une seconde partie, nous nous intéressons à la possibilité pour l’utilisateur de ne pas donner d’exemples du tout. En partant d’un CSP sans aucune contrainte, notre méthode consiste à résoudre le problème de l’utilisateur de manière classique. Grâce à un arbre de recherche, nous affectons progressivement des valeurs aux variables. Quand notre outil ne peut décider si l’affectation partielle courante est correcte ou non, nous demandons à l’utilisateur de guider la recherche sous forme de requêtes. Ces requêtes permettent de trouver des contraintes à ajouter aux modèles du CSP et ainsi améliorer la recherche. / Constraint programming allows to model many kind of problems with efficient solving methods. However, its complexity has increased these last years and its use, notably to model problems, has become limited to people with a fair expertise in the domain. This thesis deals with automating the modeling task in constraint programming. Methods already exist, with encouraging results, but many requirements are debatable. In a first part, we propose to avoid the limitation consisting, for the user, in providing solutions of the problem she aims to solve. As a replacement of these solutions, the user has to provide solutions of closed problem, i.e problem with same semantic but where variables and domains can be different. To handle this kind of data, we acquire, thanks to inductive logic programming, a more abstract model than the constraint network. When this model is learned, it is translated in the very constraint network the user aims to model. We show the limitations of learning method to build such a model due to pathological problems and explain the new algorithm we have developed to build these abstract models. In a second part, we are interesting in the possibility to the user to not provide any examples. Starting with a CSP without constraints, our method consists in solving the problem the user wants in a standard way. Thanks to a search tree, we affect to each variable a value. When our tool cannot decide if the current partial affectation is correct or not, we ask to the user, with yes/no queries, to guide the search. These queries allow to find constraints to add to the model and then to improve the quality of the search.

Le développement de la recharge sans contact de batteries comporte divers avantages pour les véhicules électriques. Cette solution est facile à utiliser, robuste et résistante aux intempéries par rapport aux câbles généralement utilisés. Le principe est basé sur le couplage magnétique entre un émetteur et un récepteur. L'objectif de cette thèse est de contribuer à proposer une norme pour permettre l’interopérabilité, c’est-à-dire, permettre à plusieurs émetteurs de fonctionner avec des récepteurs de différents fournisseurs. Comme le système doit aussi être tolérant au positionnement et doit respecter les recommandations concernant l’exposition humaine, de nombreuses configurations doivent être envisagées. Dans cette thèse, une modélisation avancée et fiable du système complet est proposée. La méthode des éléments finis est exploitée pour déterminer les caractéristiques électriques du coupleur inductif (inductances propres et mutuelles, facteur de couplage) dans différentes configurations de positionnement et d’interopérabilité. Ces valeurs permettent le dimensionnement du convertisseur à résonance. A ce stade différentes topologies de compensation sont considérées. Un modèle analytique au premier harmonique est mis en œuvre pour comparer les topologies et déterminer la fréquence de résonance globale du système. Un modèle circuit du système complet est ensuite développé pour évaluer précisément les courants et tensions. Enfin, un algorithme de régulation basé sur une méthode MPPT (Maximum Power Point Tracking) est évalué pour le réglage automatique de fréquence. A partir des courants calculés à la fréquence de résonance pour un point de fonctionnement nominal et grâce au modèle éléments finis incluant le châssis du véhicule le champ magnétique rayonné est calculé et comparé aux valeurs limites recommandées. A chaque étape de la modélisation, la sensibilité du système aux paramètres de configuration (positionnement, interopérabilité) est analysée. Des mesures effectuées au niveau du coupleur inductif et sur le système complet sont aussi utilisées dans l’analyse et permettent de valider le modèle / Development of contactless battery charging is an opportunity for electric vehicles. Compared to regular plugin cables, this solution is easy to use, robust and weather resistant. The power is transferred thanks to the magnetic coupling of inductive coils and a reduced magnetic circuit. The aim of this thesis is to contribute to propose a standard that would make possible to couple emitters with receivers from different suppliers, that is, to insure interoperability. As the system should also be tolerant to positioning and should respect human exposure recommendations, many configurations must be tested. In this thesis, an advanced and reliable modeling of the whole system is proposed. Using the finite element methods, the electrical characteristics (self, mutual inductances and coupling factor) of the inductive coupler are computed for different geometric and interoperability configurations. These values allow the dimensioning of the resonant converter. At this stage, different compensation topologies are considered. It is shown that the global resonant frequency can be derived and the topologies compared from a classical first harmonic approximation and analytical model. Then, a circuit model of the full system is developed in order to evaluate precisely the currents and voltages. Finally, the performance of a Maximum Power Point Tracking as frequency regulation algorithm is evaluated. From the currents computed at resonant frequency for the nominal operating point and the finite element model of the coupler, including the chassis of the vehicle, the radiated magnetic field is evaluated in order to check safety compliance. At each step of the modeling, the sensitivity of the system to the configuration parameters (positioning, interoperability) is analyzed. Measurements at the coupler level and for the full system are also used in this analysis and allow validating the model

This report is the basis for a Bachelor of Science thesis in engineering done at Volvo Powertrain in Gothenburg. The problem consisted of investigating a circuit with a PWM-controlled MOSFET driving a DC-motor. The problem was to investigate what caused the circuit to break the transistor. Finally an improvement of the circuit is designed making the MOSFET withstand the stressful conditions exposed to. An overall description of the problems with switching an inductive load using a MOSFET as switch is done. Some methods to protect the MOSFET from failure are also discussed. Finally a discussion is held to suggest what broke the MOSFET, and an improved design is proposed.

<p>This report is the basis for a Bachelor of Science thesis in engineering done at Volvo Powertrain in Gothenburg. The problem consisted of investigating a circuit with a PWM-controlled MOSFET driving a DC-motor. </p><p>The problem was to investigate what caused the circuit to break the transistor. Finally an improvement of the circuit is designed making the MOSFET withstand the stressful conditions exposed to. </p><p>An overall description of the problems with switching an inductive load using a MOSFET as switch is done. Some methods to protect the MOSFET from failure are also discussed. Finally a discussion is held to suggest what broke the MOSFET, and an improved design is proposed.</p>

Metamaterials display unusual electromagnetic properties, such as, a negative effective permeability and negative effective permittivity. This has sparked much interest due to possibility of negative refraction which was later confirmed by experiments. The ability of magnetically coupled resonant circuits to display an effective permeability lead to the discovery of magneto-inductive waves. These waves are only supported on arrays of magnetically coupled resonant circuits. Research into magneto-inductive waves has been largely concentrated on their use in filters and their potential use in magnetic resonance imaging. However, some work has proposed the use of magneto-inductive waveguides as a data transfer medium. This report builds on previous work which found that an optimum existed for terminal-waveguide coupling, and aims to investigate the application of magneto-inductive waves in data transfer systems. A brief overview of the topic is given along with a description of the underlying characteristics. Factors that affect the capacity of magneto-inductive wave data transfer systems, such as inter element coupling, were identified. Two novel structures, both with the intent of increasing the bandwidth via different methods, are studied. One, by making a pseudo one-dimensional channel from a two-dimensional structure, and the other by using a dual-layer design to increase the coupling between adjacent elements. Both systems are modelled, using simple circuit theory and the impedance matrix method, and a comparison between simulated behaviour and experimental observation was made. There is discussion about the differences between experiment and simulation as well as their limitations. Magneto-inductive wave data transfer systems are eventually expected to support multiple terminals and as previous research only considered two-terminal systems, an investigation into the response of a one- and two-dimensional system with a blocking terminal was undertaken. The system was modelled, again using simple circuit theory and the impedance matrix method, and simulation and experiment were compared. As a whole, the simulations showed good agreement with experiments, after some initial adjustments. Both one- and two-dimensional systems showed that their performance was not severely effected by a blocking terminal. This suggests that magneto-inductive waveguides could support more terminals.