Cette thèse porte sur des micro-réseaux AC isolées qui permettent l’intégration des ressources énergétiques distribuées (DER) pouvant fournir leur énergie d'alimentation existante de manière contrôlée pour assurer le bon fonctionnement global du système. L'interconnexion d'un DER à une micro-réseau s'effectue habituellement en utilisant un convertisseur d'interface distribué (DIC) (i.e. un bloc d'interface d'électronique de puissance générale) qui est constitué d’un module de convertisseur à l'entrée de la source, un onduleur de tension (VSI), un module d'interfaçage de sortie, et le module de commande. Dans cette thèse on réalise plusieurs lois de commande basées sur des méthodes décentralisées. L'accent principal est mis sur les fonctions "Droop" qui ont la tâche de maintenir un équilibre de distribution d'énergie entre les différentes sources énergétiques connectées à la micro-réseau. L'objectif est d'assurer la stabilité du système et d’améliorer les performances dynamiques en partageant la puissance entre les différents générateurs d’électricité distribués (DGs) en fonction de leur puissance nominale. Le développement d'une analyse de stabilité en boucle fermée s’avère utile pour étudier la dynamique du système afin d'obtenir une réponse transitoire souhaitée qui permet d'identifier les paramètres de contrôle de boucle appropriés. L'amélioration de la qualité d’énergie des micro-réseaux est également un objectif de cette thèse. La réduction des distorsions harmoniques de la tension de sortie en présence de charges linéaires et non linéaires est prise en compte dans nos travaux. D'autres aspects seront étudiés sur la façon de traiter les charges constantes connectées au réseau et les grandes perturbations qu’ils produisent. Cela donne lieu à d'autres études de recherche portant sur la stabilité grand signal des micro-réseaux / This thesis deals with islanded AC microgrid that allows any integration of Distributed Energy Resources (DERs) that may provide their existing supply energy in a controlled manner to insure overall system functioning. The interconnection of a DER to a microgrid is done usually by using a Distributed Interface Converter (DIC), a general power electronics interface block, which consists of a source input converter module, a Voltage Source Inverter module (VSI), an output interface module, and the controller module. The thesis realizes several control laws based on decentralized methods. The major focus is on the Droop functions that are responsible for providing a power distribution balance between different Energy Resources connected to a microgrid. The aim is to insure system stability and better dynamic performance when sharing the power between different DGs as function to their nominal power. Developing a closed loop stability analysis is useful for studying system dynamics in order to obtain a desired transient response that allows identifying the proper loop control parameters. Power Quality enhancement in microgrids is also a purpose of this research. The reduction of harmonic distortions of the output voltage when supplying linear and non-linear loads are taken in consideration in this thesis. Further aspects will be studied about how to deal with constant power loads connected to the grid and the large perturbations exerted. This results to further research studies that deal with large-signal stability of microgrids

Le routage dans Internet est basé sur des tables dites de routage, formées de blocs d’adresses IP. Cependant, la construction et la maintenance de telles tables de routage nécessitent l’utilisation de protocoles complexes qui ne passent pas à l’échelle en termes de mémoire et d’utilisation CPU. De plus, l’expérience montre que le plan d’adressage IP est insuffisant, car la sémantique d’une adresse IP est à la fois un identificateur et un localisateur. Dans nos travaux, nous proposons un système de réseau recouvrant pair-à-pair libre de toute contrainte topologique et utilisant des coordonnées virtuelles prises dans le plan hyperbolique nommé CLOAK (Covering Layer Of Abstract Knowledge en anglais). Les schémas de routages locaux basés sur des coordonnées virtuelles extraites du plan hyperbolique ont suscité un intérêt considérable ces dernières années. Dans cette thèse, nous proposons une nouvelle approche pour saisir le potentiel de la géométrie hyperbolique. L’objectif est de construire un système extensible et fiable pour créer et gérer des réseaux recouvrants dans Internet. Le système est implémenté comme une infrastructure pair-à-pair structuré basé sur les protocoles de la couche transport entre les pairs. Quant à l’organisation des données dans l’espace virtuel, nous employons la réplication pour améliorer la disponibilité et l’accessibilité des objets de l’overlay potentiellement instable. Nous avons implémenté et évalué différentes méthodes de réplication (réplication radiale, réplication circulaire).A l’aide de simulations, nous évaluons notre proposition à travers un certain nombre de métriques et nous montrons que les réseaux recouvrants pair-à-pair basés sur la géométrie hyperbolique ont de bonnes performances par rapport aux autres DHT existantes tout en introduisant flexibilité et robustesse dans les réseaux recouvrants dynamiques. / Internet routing is based on forwarding tables populated by blocks of IP addresses. However, the construction and maintenance of such tables require the use of complex routing protocols that are typically not scalable in terms of memory and CPU usage. Moreover, experience shows that the IP addressing plane is insufficient due to the semantic of an IPaddress being both an identifier and a locator. In this paper, we propose a P2P overlay system of freed topology and using virtual coordinates taken from the hyperbolic plane named CLOAK(Covering Layer Of Abstract Knowledge en anglais). Local knowledge routing schemes based on virtual coordinates taken from the hyperbolic plane have attracted considerable interest in recent years. In this thesis we propose a new approach for seizing the power of the hyperbolic geometry. We aim at building a scalable and reliable system for creating and managing overlay networks over the Internet. The system is implemented as a structured peer-to-peer infrastructure based on the transport layer connections between the peers. Concerning data organisation in the virtual space, we use replication strategy for improve overlay objects disponibilty and accessibility in context potentially unstable. We have implemented and evaluated various replication methods (radial replication, circular replication). Using simulations, we assess our proposal across a certain number of metric and show that overlay Peer-to-Peer network based on the hyperbolic geometry have good performances in comparison with other existent DHT while introducing suppleness and robustness in the dynamic overlay network.

A repetitive control method for output voltage control of a three phase uninterruptible power supply (UPS) with isolation transformer is investigated. In the method voltage control loop is employed in the stationary dq frame. The controller eliminates the periodic errors on the output voltages due to inverter voltage nonlinearity and load disturbances. The controller design and implementation details are given. The controller is implemented on a 5-kVA UPS prototype which is constructed in laboratory. Linear and nonlinear loads for balanced and unbalanced load operating conditions are considered. The steady-state and dynamic performance of the control method are investigated in detail. The theory of the control strategy is verified by means of simulations and experiments.

A method for high performance output voltage control of a four-leg inverter based three-phase transformerless UPS is proposed. Voltage control loop is employed and the method employs stationary frame resonant filter controllers for the fundamental and harmonic frequency components. A capacitor current feedback loop provides active damping and enhances the output voltage dynamic performance. The controller design and implementation details are given. Linear and nonlinear loads for balanced and unbalanced load operating conditions are considered. The steadystate and dynamic performance of the UPS are investigated in detail. A scalar PWM method with implementation simplicity and high performance is proposed and implemented. The control and PWM methods are proven by means of theory, simulations, and experiments.

Une nouvelle méthode de test pour les convertisseurs ADC et DAC embarqués dans un système complexe a été développée en prenant en compte les nouvelles contraintes affectant le test. Ces contraintes, dues aux tendances de design de systèmes, sont un nombre réduit de point d'accès aux entrées/sorties des blocs analogiques du système et une augmentation galopante du nombre et des performances des convertisseurs intégrés. La méthode proposée consiste à connecter les convertisseurs DAC et ADC dans le domaine analogique pour n'avoir besoin que d'instruments de test numériques pour générer et capturer les signaux de test. Un algorithme de traitement du signal a été développé pour discriminer les erreurs des DACs et ADCs. Cet algorithme a été validé par simulation et par expérimentation sur des produits commercialisés par NXP. La dernière partie de la thèse a consisté à développer de nouvelles applications pour l'algorithme.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The increase in linear and non-linear loads experienced by Brazil in recent years has changed the way distribution networks are planned and Operated. In addition, the competitiveness of the market and the demand for the improvement in power quality indexes mean that current e orts are increasingly focused on areas such as voltage profile control and voltage harmonic distortion control. This work deals, exactly, with the Integrated control of voltage and harmonic voltage distortion (volt/thd) in distribution systems, within the scope of planning, through the insertion of passive harmonics filters and voltage regulators. To solve the problem in question, a multiobjective algorithm, the NSGA-II, is applied, since the presented problem can be treated as a combinatorial optimization problem. The power summation method is used as an alternative for the resolution of the load flow. While the current injection method is used as a calculation of the harmonic flow. The mathematical models of the network components were presented, taking into account the influence of frequency, in a detailed way. The proposed algorithm was applied in benchmark systems, a 34-bus and a 104-bus, the systems were simulated with and without the presence of the devices for comparison and validation of the results. / O aumento de cargas, lineares e não-lineares, vivenciado pelo Brasil nos últimos anos, tem alterado a maneira com as redes de distribuição são planejadas e operadas. Além disso, a competitividade do mercado e exigência pela melhoria nos índices de qualidade da energia fazem com que os esforços atuais sejam cada vez mais direcionados para áreas como o controle do perfil de tensão e o controle das distorções harmônicas de tensão. Esta dissertação trata, exatamente, do controle integrado de tensão e distorção harmônica de tensão (volt/dht) em sistemas de distribuição, no âmbito do planejamento, através da inserção de filtros harmônicos passivos e reguladores de tensão. Para resolver o problema em questão, um algoritmo multiobjetivo, o NSGA-II, é aplicado, uma vez que o problema apresentado é tratado como um problema de otimização combinatória. O método da soma de potências é utilizado como alternativa para a resolução do fluxo de carga. Enquanto que o método da injeção de correntes é utilizado como cálculo do fluxo de harmônicos. Os modelos matemáticos dos componentes da rede foram apresentados, levando-se em consideração a influência da frequência, de forma detalhada. O algoritmo proposto foi aplicado em sistemas teste de 34 e 104 barras e os sistemas foram simulados com e sem a presença dos dispositivos para efeito de comparação e validação dos resultados.

The diploma thesis deals with analysis, validation, measurement of parameters of the commercially available current multiplies (namely the EL2082 and EL4083) and their applications in practice. Control analysis are carried out in OrCAD PSpice program and compared with values from datasheets. Control analysis are focused on AC and DC characteristics of these active blocks. There are discusses the input impedance, the output impedance, the current gain and the possibility of electronic adjusting. The parameters of the elements were verified by measurements. Proposals for circuit applications (selective circuit, oscillator, frequency filter) with EL2082 and EL4083 are presented and analyzed in the program OrCAD. Three oscillator circuit designs are experimentally tested and the results are compared with the theoretical expectations and simulations in OrCAD. The possibility of electronic control for oscillators is examined. Also the sensitivity and the tolerance analysis are carried out. The constructional details of oscillators are presented at the end of this work.

This master thesis has been carried out in collaboration with Saab, Avionics Systems in Jönköping, Sweden, during the spring of 2017. The thesis investigates unidirectional rectifier topologies in aircraft and the focus has been on evaluating the power quality requirements according to the aircraft standards, in the course of the More Electric Aircraft concept. Both passive and active power factor correction topologies are considered, discussed and compared. Simulation models are designed in MATLAB/Simulink and the procedures are presented. A modular concept regarding components is discussed where different power supplies and loads are considered. The simulations present both a passive 12-pulse auto-transformer rectifier unit and an active Delta-switch rectifier fulfilling requirements for aircraft such as the total harmonic distortion of the supply current. In addition, the input power factor is close to unity and an efficiency greater than 97% is obtained. Lastly, future aspects of each topology are discussed and necessary improvements to obtain realistic simulation models are presented.

The aim of this thesis was to develop user interface in LabVIEW to make typical measurements with spectral analyzer HP89410A There is introduced the theory of operation of an analogue heterodyne and a digital FFT spectral analyzer. It is explained the background of the Fast Fourier Transform. There are discussed the key settings in measuring with FTT analyzer, like window function, bandwidth, number of frequency points, or the averaging. Further is described the program, which was developed for measuring frequency characteristic by white noise and by stepped measurement. It was also made a module for measuring Signal to Noise Ratio and module for Total Harmonic Distortion. In the last part of this thesis are shown the results of processed exemplar measurements.

This Diploma thesis deals with assessment of the influence of two fundamental types of resistance welders operation on chosen power quality parameters at the point of common coupling (PCC) of the power network. The assessed parameters of power quality are the total harmonic distortion of the supply voltage, asymmetry of the supply voltage and the level of short term flicker at the point of common coupling. The assessment is based on the comparison of the results of computer simulations done in PSCad 4.2.0 with the requirements of technical standards. The outcome of this thesis is the determination of allowable limits for physical and operation parameters for the general arrangement of a power distribution network and a resistance welder that should guarantee the power quality compliance.