This thesis advances the state of the art in modeling electric machines in electro-magnetic transient simulation programs, particularly in real-time digital simulators. A new tool, developed in this thesis, expands the application of real-time digital simulators to closed-loop testing of protection relays designed to protect synchronous machines during internal faults. To evaluate the inductances of synchronous machines, a winding function approach was developed in this thesis which is capable of taking into account both the actual distribution of windings and the shape of the pole-arc. Factors such as MMF drop in the iron and effects of slots are compensated by evaluating the effective permeance function of the machine using experimentally measured values of d-, q- and 0- axis inductances. In this winding function approach, the effects of magnetic saturation are also included by considering the actual distribution of magneto-motive force in each loading condition of the machine. The inductances of an experimental machine are evaluated using this approach and validated using the finite-element method and laboratory measurements. This thesis also proposes an embedded phase-domain approach for time-domain simulation of the machine model in electromagnetic transients programs. The approach significantly improves the numerical stability of the simulations. Special numerical techniques are introduced, which speed up the execution of the algorithm as needed for real-time simulation. The machine model is validated in healthy and faulted conditions using simulations and laboratory experiments. Effects of damper grid representation on simulating turn-to-turn faults are investigated. The capability of this new real-time synchronous machine model in closed-loop testing of synchronous machines ground- faults protection relays is clearly demonstrated.

Geomagnetic disturbances that result from solar activities can affect technological systems such as power networks. They may cause DC currents in power networks and saturation of the core in power transformers that leads to destruction in the transformer performance. This phenomena result in unwanted influences on power transformers and the power system. Very asymmetric magnetization current, increasing losses and creation of hot spots in the core, in the windings, and the metallic structural parts are adverse effects that occur in transformers. Also, increasing demand of reactive power and malfunction of protective relays menaces the power network stability. Damages in large power transformers and blackouts in networks have occurred due to this phenomenon. Hence, studies regarding this subject have taken the attention of researchers during the last decades. However, a gap of a comprehensive analysis still remains. Thus, the main aim of this project is to reach to a deep understanding of the phenomena and to come up with a solution for a decrease of the undesired effects of GIC. Achieving this goal requires an improvement of the electromagnetic models of transformers which include a hysteresis model, numerical techniques, and transient analysis. In this project, a new algorithm for digital measurement of the magnetic materials is developed and implemented. It enhances the abilities of accurate measurements and an improved hysteresis model has been worked out. Also, a novel differential scalar hysteresis model is suggested that easily can be implemented in numerical methods. Two and three dimensional finite element models of various core types of power transformers are created to study the effect of DC magnetization on transformers. In order to enhance the numerical tools for analysis of low frequency transients related to power transformers and the network, a novel topological based time step transformer model has been outlined. The model can employ a detailed magnetic circuit and consider nonlinearity, hysteresis and eddy current effects of power transformers. Furthermore, the proposed model can be used in the design process of transformers and even extend other application such as analysis of electrical machines. The numerical and experimental studies in this project lead to understanding the mechanism that a geomantic disturbance affects power transformers and networks. The revealed results conclude with proposals for mitigation strategies against these phenomena. / <p>QC 20150210</p>

This diploma thesis deals with hot-formed helical compression springs. The first part of the thesis describes related problems and determines market potential. Following theoretical part describes the influence of contact line on behaviour of springs and compares it with normative regulations. Methods suitable for determination of helix shape are covered in the next part. The last part focuses on practical measurement, in which the change of helix shape during manufacture was observed. The main output of this diplomat thesis is suggestion of measures that should contribute to both optimization of manufacture and verification of FEM model.

A l’heure où la distribution de l’énergie électrique reste encore en discussion pour les nouvelles générations d’avions de transports civils ou militaires, une remise en cause du niveau des tensions continues disponibles pourrait porter les bus de tension de 270Vdc à 540Vdc. De fait, les équipementiers devront proposer des produits facilement adaptables à ces deux niveaux de tension. Par ailleurs, la course au rendement nécessite de revoir les systèmes actuels en proposant des versions plus compactes, fonctionnant à des meilleurs niveaux de rendement. L’atteinte de ces objectifs peut passer par une rupture technologique qui devrait s’opérer dans le domaine de la conversion d’énergie avec l’avènement, d’une part, des composants « grand gap », d’autre part, l’exploitation de structures innovantes de convertisseurs de puissance autore configurables. Les systèmes associant plusieurs convertisseurs et plusieurs machines, appelés communément Systèmes Multi-Convertisseurs Multi-Machines (SMCMM), jouent également un rôle prépondérant grâce aux avantages qu’ils présentent tels que, la modularité, la sûreté et l’accroissement de puissance. Néanmoins, si a priori, l’innovation technologique porte sur le convertisseur statique, le rendement d’un système électromécanique alliant convertisseur et machine ne correspond pas en général au produit des rendements de chacun des composants qui le constituent. En effet, le fonctionnement global fait apparaître de nouvelles problématiques. Dans ce contexte, la ligne directrice de ces travaux de recherche porte sur une méthodologie générale et le développement d’outils qui permettent d’étudier ces systèmes dans leur globalité. L’enjeu scientifique de cette étude consiste à adapter au mieux la machine à son convertisseur, optimiser la qualité du couple (amplitude et ondulations), donc à dimensionner et optimiser une machine qui réponde non seulement à la fonction principale visée par l’application, produire un couple mécanique à une vitesse donnée, mais qui satisfasse aussi une, voire plusieurs fonctionnalités requises pour l’utilisation d’onduleurs reconfigurables en tension. Afin de constituer une palette d’outils qui permettra de développer une méthodologie générale d’analyse des SMCMM, un outil de génération et de caractérisation systématique des bobinages et des aimants permanents est développé. Ce premier outil couplé à un modèle de type champ, basé sur la résolution analytique des équations du champ magnétique, est capable de fournir les performances électromagnétiques de la machine en fonction des critères du concepteur. Ensuite, un second outil qui permet d’appliquer la théorie d’une vision de conception par l’adéquation des sources du champ dans une machine, est développé. Nous pouvons alors rechercher la possibilité de maximiser le couple en adaptant, soit les bobinages, soit les aimants permanents. Pour étendre les précédents résultats à un cas général, un problème d’optimisation est formulé. Pour cela, un problème inverse à variables mixtes, relations complexes et non linéaires, est résolu avec un algorithme de type « boîte noire ». Les travaux se focalisent ensuite sur l’intégration de la fonction coupleur magnétique, puis sur la mise en évidence des conditions de fonctionnement optimal d’une machine synchrone à aimants permanents montés en surface et à double étoile (MSAPDE), alimentée par deux convertisseurs en parallèle reconfigurables en tension à commande entrelacée. Cette démarche est une première approche concrète de l’intégration machine convertisseur. Les courants induits dans les parties conductrices de la machine en mouvement sont modélisés afin de vérifier en fonction de la fréquence, leurs effets sur la fonction de coupleur magnétique. Finalement, après des simulations numériques qui permettent d’analyser et de classifier les avantages et les inconvénients de plusieurs solutions de machines, la réalisation de deux démonstrateurs de MSAPDE à coupleur intégré est initiée. / At the moment, distribution of electrical power is still being discussed for the new generations of civil and military aircraft. Level of DC voltage available is challenging and could take voltage from 270Vdc to 540Vdc. Hence, equipment suppliers must propose products easily adaptable to these two voltage levels. Otherwise, the race for better performances requires the revision existing systems by offering more compact versions functioning at better efficiency levels. Achieving these goals may be through a technological breakthrough that should be operated in the field of energy conversion with advent of both components "high band gap", and the use of innovative structures of self-reconfigurable power converters. Systems that combine several converters and several machines, commonly called Multi-Converters Multi-Machines Systems (SMCMM), also play a prominent part thanks to their advantages such as, modularity, safety and increased power. Nevertheless, if in principle, technical innovation concerns with the static converter, the efficiency of an electromechanical system which combines machine and converter does not correspond generally to the efficiency product of each constituent component. Indeed, overall functioning reveals new problems. In this context, the guidelines for this research work focus on a general methodology and the development of tools in order to study these systems as a whole. The scientific challenge of this study consists in adapting a machine to its converter, optimizing the torque quality (amplitude and ripples), so to size and to optimize a machine that meets not only the main function covered by the application, i.e. to produce a mechanical torque at a given speed, but also satisfies one or several functionalities required for using reconfigurable voltage inverters. In order to provide a range of tools that will allow the development of a general methodology for SMCMM analysis, a tool for automatic generating and characterizing windings and permanent magnets has been developed. This first tool coupled with an analytical model of field type, based on solving equations of magnetic field, is able to provide electromagnetic performances of the machine according to the designer's criteria. A second tool which allows us to apply theory of a design vision by the field sources adequacy in a machine has been developed. Consequently, we can look for possibility to maximize torque by adapting either windings or permanent magnets. To extend previous results to a general case, an optimization problem is formulated. For this purpose, an inverse problem with mixed variables, complex and non-linear relations, is solved with a "black box" algorithm. The work focus on magnetic coupler function integration, on the identification of optimal operating conditions of a synchronous machine with surface-mounted permanent magnets (AP) and double star (MSAPDE), supplied by two reconfigurable parallel interleaved inverters. This approach is a first practical step into machineconverter integration. Eddy currents in the moving conductive parts of the machine are modeled in order to check their effects on the magnetic coupler function according to frequency. Finally, after numerical simulations which allow us to analyze and classify pros and cons of several machine solutions, the fulfillment of two MSAPDE demonstrators integrating magnetic coupler is initiated.

Les composants magnétiques planaires (inductance et transformateur) occupent une place importante dans certains circuits intégrés utilisés en haute fréquence. Leur miniaturisation et leur intégration vont de pair avec celles des circuits électroniques qui évoluent constamment surtout pour les appareils portables. Quelques travaux scientifiques ont permis d’identifier les différents mécanismes à l’origine de pertes dans les composants magnétiques planaires, afin de les limiter. Les pertes dans les enroulements sont classiquement prises en compte par une résistance r(f) fonction de la fréquence. La détermination, à partir des paramètres S obtenus par mesure ou simulation, de la résistance r(f) constitue à ce jour un sujet d’étude à part entière, les paramètres S étant les seuls paramètres que l’on peut obtenir au-delà de la centaine de MHz. Pour contribuer à la résolution de ce problème, nous avons proposé une méthode prenant en compte toutes les pertes dans le bobinage. Cette méthode de détermination de la résistance en fonction de la fréquence se fait dans trois domaines de fréquence : - en très basse fréquence, la rDC est obtenue par calcul ou mesurée à l’aide d’un matériel basse fréquence, - aux "moyennes fréquences" lorsque les impédances R et Lω ne sont pas trop différentes, les phénomènes capacitifs pouvant être négligés, - aux résonances en très haute fréquence. L’application de cette méthode sur trois structures différentes (inductance à air de plusieurs spires, à air à une spire en oméga et à une couche de matériau magnétique) a permis de : - observer une bonne corrélation entre simulation et mesure, -valider l’évolution des pertes en fonction de la fréquence, -séparer les effets de peau et de proximité, -séparer les pertes fer et les pertes cuivre pour une inductance à couche magnétique / Planar magnetic components (transformer and inductor) have become a big part in some integrated circuits used in high frequency. Miniaturization and integration of magnetic components go hand in hand with the ones of electronics that constantly evolves especially for portable devices. A few scientific studies have identified the different mechanisms of losses in planar magnetic components. Winding losses are generally taken into account using a resistance r(f) versus frequency.The use of scattering parameters S to determine resistance r(f) represents a comprehensive research project ; S parameters that can be obtained either by measurement or by simulation, are the only parameters which one can get at high frequencies (above 100MHz). To solve this problem, we have proposed a method taking into account all winding losses. Our approach for determining r(f) has to be applied in 3 frequency domains: - at very low frequency, r(f) = rDC and its value is either calculated or measured using low frequency equipment, - in the middle frequency range, capacitive coupling can be neglected while impedances R and Lω are in the same order of magnitude, - at very high resonance frequencies.This method has been implemented for 3 different structures (coreless inductor with several turns of coil, Omega shape coreless inductor with one turn and inductor with a magnetic layer) leads to : - observe a good correlation between simulation and measurement, - validate the evolution of losses versus frequency, - separate skin effects and proximity effects, - separate iron losses and winding losses

Made available in DSpace on 2014-12-17T14:56:08Z (GMT). No. of bitstreams: 1 ValciFV_TESE.pdf: 3670403 bytes, checksum: d8b060478983488207d8885853eac60d (MD5) Previous issue date: 2012-11-05 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Electrical Motors transform electrical energy into mechanic energy in a relatively easy way. In some specific applications, there is a need for electrical motors to function with noncontaminated fluids, in high speed systems, under inhospitable conditions, or yet, in local of difficult access and considerable depth. In these cases, the motors with mechanical bearings are not adequate as their wear give rise to maintenance. A possible solution for these problems stems from two different alternatives: motors with magnetic bearings, that increase the length of the machine (not convenient), and the bearingless motors that aggregate compactness. Induction motors have been used more and more in research, as they confer more robustness to bearingless motors compared to other types of machines building with others motors. The research that has already been carried out with bearingless induction motors utilized prototypes that had their structures of stator/rotor modified, that differ most of the times from the conventional induction motors. The goal of this work is to study the viability of the use of conventional induction Motors for the beringless motors applications, pointing out the types of Motors of this category that can be more useful. The study uses the Finite Elements Method (FEM). As a means of validation, a conventional induction motor with squirrel-cage rotor was successfully used for the beringless motor application of the divided winding type, confirming the proposed thesis. The controlling system was implemented in a Digital Signal Processor (DSP) / Motores el?tricos transformam energia el?trica em energia mec?nica com relativa facilidade. Em algumas aplica??es particulares, necessita-se de motores el?tricos para trabalhar com flu?dos sem contamina??o, em regime de altas velocidades, em condi??es in?spitas, ou, ainda, em locais de dif?cil acesso e ? profundidade bastante consider?vel. Nestes casos, os motores com mancais mec?nicos, cujo desgaste ocasiona a necessidade de manuten??es, n?o s?o adequados. Uma solu??o poss?vel para este problema adv?m de duas alternativas: motores com mancais magn?ticos, que t?m o inconveniente de aumentar o comprimento da m?quina, e motores-mancais, que agregam compacidade. Motores de indu??o t?m sido cada vez mais utilizados em pesquisas, pois conferem maior robustez aos motores-mancais comparados a esses tipos de m?quinas constru?das com outros motores. As pesquisas j? realizadas com motores-mancais de indu??o utilizaram prot?tipos, cujas estruturas do estator e/ou rotor foram modificadas, diferindo em grande parte dos motores de indu??o convencionais. ? objetivo deste trabalho, estudar a viabilidade do uso dos motores de indu??o convencionais para a aplica??o de motores-mancais, apontando os tipos de motores dessa categoria que mais se ad?quam. O estudo utiliza o M?todo dos Elementos Finitos FEM. Como comprova??o, um motor de indu??o convencional com rotor gaiola de esquilo foi utilizado com sucesso para a aplica??o de motor-mancal do tipo enrolamento dividido, ratificando a tese proposta. O sistema de controle foi implementado em um Processador Digital de Sinais DSP

Le réseau électrique de bord des avions devient le principal vecteur de transmission de l'énergie utilisée en dehors de celle réservée à la propulsion. Le réseau électrique remplace progressivement les réseaux hydrauliques et aérauliques qui assurent respectivement les contrôles de vol et le confort dans la cabine des avions actuels. Pour transmettre une puissance électrique plus importante sans augmenter la masse des conducteurs, un nouveau standard a été défini, le réseau de bord des avions plus électriques sera continu et sa tension est fixée à 540V. En conséquence, les convertisseurs statiques seront systématiquement utilisés pour commander les actionneurs électriques. Des contraintes électriques nettement plus importantes seront appliquées aux bobinages des machines en plus de celles qui sont inhérente à l'aéronautique. Pour obtenir la sureté de fonctionnement requise, la surveillance du vieillissement de l'isolation des machines électriques embarquées devient indispensable. Le travail effectué dans cette thèse est centré sur la définition d’un nouvel indicateur de vieillissement de l’isolation des bobinages des machines électriques utilisées en aéronautique. Le nouvel indicateur delta-C est basé sur la corrélation entre l'augmentation de la capacité inter-spires du bobinage et la réduction des performances caractérisée principalement par la réduction du seuil d'apparition des décharges partielles. La partie expérimentale des travaux est importante; le mémoire donne les résultats des campagnes de vieillissement accéléré d'un grand nombre d'échantillons de fil émaillé standard. Ces résultats permettent de définir des seuils critiques des variations du nouvel indicateur delta-C en fonction du profil de mission de l'actionneur. Le nouvel indicateur delta-C est corrélé avec un paramètre facilement mesurable sur une machine électrique en fonctionnement qui est la fréquence de résonance du bobinage. Un outil numérique est développé pour déterminer les fréquences de résonances à surveiller en fonction de la géométrie et de la technologie du bobinage de la machine. Les prédictions des fréquences déterminées par l'outil numérique développé sont vérifiées par des mesures faites sur des bobines vieillies artificiellement. L'étude est étendue à l'influence du câble d'alimentation de la machine. Les limites de fonctionnement du système de surveillance proposé sont définies pour différentes distances entre la machine et le point de connexion des systèmes de mesure. / For modern aircrafts, the onboard electrical grid becomes the main energy transmission system apart from energy reserved for propulsion. Electrical systems are gradually replacing hydraulic and air systems providing respectively flight controls and cabin comfort in current aircrafts. To transmit higher electrical power without increasing the conductors’ masses, a new standard has been set, the grid of more electrical aircrafts will be 540 VDC. As a result, static converters will systematically be used to drive the electrical actuators. Substantially higher electrical constraints will be applied to electrical machine windings, in addition to those inherent in aeronautics. To obtain the required operational safety, the monitoring of the insulation for onboard electrical embedded machines has become indispensable. This thesis work is focused on the definition of a new aging indicator for the electrical insulation of machine used in aeronautics. The new delta-C indicator is based on the correlation between the increase in the turn-to-turn winding capacitance and reduction of performance mainly characterized by the decrease of Partial Discharge Inception Voltage (PDIV). The experimental part of this work is considerable; the thesis gives the results of accelerated aging tests on a large number of enameled wire standard samples. These results make it possible to define critical threshold for the new delta-C indicator depending on the mission profile of the actuator. The new delta-C indicator is correlated with an easily measurable parameter on an operating electrical machine, i.e. the resonance frequencies of the winding. A numerical tool was developed to determine the resonance frequencies to be monitored according to the geometry and the technology of the winding machine. The prediction frequencies determined by the developed numerical tool have been verified by measurements on artificially aged coils. The study has been extended to the influence of the supply cable of the electrical machine. The operating limits of the proposed monitoring system are defined for various distances between the electrical machine and the connection point of the measurement systems.

The thesis Diagnostics of rotating electric machines deals with the theory of diagnostics of rotating machines, focusing especially on the diagnosis of asynchronous motors of high power. Due to the importance of maintaining the trouble-free condition of these machines with regard to serviceability, the importance of their diagnosis is growing. Due to inappropriate working conditions or for many other reasons, different types of malfunctions may occur in the machine. The list and the way of occurrence of possible failures are included and explained in this thesis. With the growing age of the machine, it is important to check the insulation status through insulation testing. These tests are performed in the practical part of the thesis and the results are presented. In the case of asynchronous machines, each anomaly leaves a signature in the form of an electrical, magnetic or vibrational signal. These signals are analyzed and evaluated using a specific measuring equipment with the intention of deciding on the current state of the machine. Motor current signature analysis (MCSA) is considered to be the main diagnostic method of asynchronous machines in this thesis. This method is described in detail in this paper and is being applied in electrical engineering.

This diploma thesis deals with the possibility of using a concentrated winding in an induction motor and the use of copper bars in a rotor cage. The first part of the thesis explains the basic theoretical knowledge of the operation and principle of the induction machine. In this theoretical part we will learn what is actually a concentrated winding and how it is placed on the stator. The second part is focused on the analytical design of the machine with classical distributed winding and with concentrated winding. The third theoretical part is an introduction to the issue of influencing the motor harmonics. The last final part of the thesis shows differences in operational properties of designed machines.

Dizertační práce se zabývá modelováním a řízením elektrických pohonů během poruchových stavů. Práce se obzvláště zaměřuje na více-fázové motory. První část práce se zabývá matematickými rovnicemi obecného více-fázového motoru a následným odvozením n-krát troj-fázového zapojení motoru. Modely v dq souřadnicovém systému a modely ve statorových souřadnicích jsou navrženy pro simulaci chování motoru během poruchových stavů. Další část práce se zabývá analýzou poruch ve více-fázových motorech s využitím matematických modelů. Různé vnitřní struktury vinutí motoru jsou analyzovány z pohledu možného řízení během poruchového stavu. Taktéž je prezentováno chování těchto různých struktur motoru během poruchových stavů. Předmětem analýzy jsou elektrické poruchy vinutí motoru a elektrické poruchy výkonové elektroniky. Poslední část práce se zabývá testováním navrženého řídícího algoritmu a navržených kompenzačních strategií pro poruchy na reálných motorech. Pro testování byl použit segregovaný dvakrát troj-fázový motor a experimentální motor s odbočkami pro emulaci poruch vinutí. Provedené testy prokázaly, že vhodně navrhnutý motor v kombinaci se správným řídícím algoritmem a výkonovou elektronikou dokáže zaručit kontinuální běh pohonu i během poruchy.