Small signal oscillation has been always a major concern in the operation of power systems. In a generator, the electromechanical coupling between the rotor and the rest of the system causes it to behave in a manner similar to a spring mass damper system. Following any disturbance, such as sudden change in loads, actuations in the output of turbine and faults etc. it exhibits an oscillatory behaviour around the equilibrium state. The use of fast acting high gain AVRs and evolution of large interconnected power systems with transfer of bulk power across weak transmission links have further aggravated the problem of these low frequency oscillations. Small oscillations in the range of about 0.1Hz to 3.5Hz can persist for long periods, limiting the power transfer capability of the transmission lines. These oscillations can be reduced by incorporating auxiliary controllers on generator excitation system. Power System Stabilizers (PSSs) were developed to produce additional damping by modulating the generator excitation voltage. Designing effective PSS for all operating conditions especially in large interconnected power systems still remains a difficult and challenging task. More and more power electronic based controllers have been and will be used in power systems. Many of these controllers such as Static Var Compensators (SVCs), Static Synchronous Compensators (STATCOMs) and Unified Power Flow Controllers (UPFCs) etc., are incorporated in power transmission networks to improve its operational capability. In addition, some of the energy storage systems such as Battery Energy Storage systems (BESS), Super conducting Magnetic Energy Storage System (SMES) as well large non-conventional energy sources are also increasingly being integrated with the power grid. With large integration of these devices, there is a significant impact on system stability, more importantly on small signal oscillatory instability of the power system. This thesis primarily focuses on impact of such devices on small signal oscillatory stability of the power systems. More specifically in this thesis small signal stability analysis of a Single Machine Infinite Bus (SMIB) system with a grid connected wind powered Permanent Magnet Synchronous Generator (PMSG) has been presented. A SMIB system has been purposely chosen so that general conclusions can be obtained on the behaviour of the embedded STATCOM/Energy Source (ES) system on system stability. With a better understanding of the impact of such a system it would be probably possible to analyze more complicated multimachine power system and their impact on system stability. Small signal model of the complete system which comprises the generator, transmission network, inter connecting STATCOM, the wind power generator and all associated controllers has been developed. The performances of the system following a small disturbance at various operating conditions have been analyzed. To obtain quantitative estimates of the damping and synchronizing torques generated in the system, expressions for damping and synchronizing torque clients have been developed. With these analyses, the relative impact of the STATCOM and STATCOM with ES on system performance have been assessed. It is shown that with active and reactive power modulation capabilities effective and efficient control of small signal oscillations in power systems can be achieved.

L’alternateur étudié dans cette thèse équipe une éolienne flottante à axe vertical. Il s’agit d’unemachine synchrone de 2MW, polyphasée, bobinée sur plots, à pas fractionnaire, à aimants et à prisedirecte. L’objectif majeur de la thèse est la caractérisation de cet alternateur afin d’en évaluer lesperformances. Une modélisation analytique de la perméance d'entrefer et de la force magnétomotriceont conduit à l'étude de l'induction d'entrefer dont le contenu harmonique s'est révélé êtreparticulièrement riche. La caractérisation a également porté sur la détermination des inductancespropres et mutuelles, avec un calage du modèle effectué en exploitant des mesures expérimentalesfaites à l’arrêt. La particularité de la machine étudiée nous a amené à considérer un enroulement fictiféquivalent dans le but de déterminer les inductances cycliques, nécessaires à l'établissement du schémamonophasé équivalent. De plus, le fonctionnement back to back de la machine a été étudié et simulé. Ilpermet de faire des tests de la machine elle-même mais aussi des éléments de la chaîne de conversion,sans l'utilisation d'une deuxième machine ou des pâles pour entraîner le rotor du prototype. Il offre enplus la possibilité de tester différents type de fonctionnements et d'évaluer la puissance que peutproduire la machine : différents scénario de fonctionnement ont été simulés et les paramètresnécessaires aux essais sur site ont été définis. Le fonctionnement back to back a fait l’objetd’investigation sur une machine synchrone classique. Les difficultés de fonctionnement ontnotamment pu être mises en évidence avec une modélisation analytique des phénomènesélectromagnétique qui s'y produisent et des essais expérimentaux. / The studied alternator equips a vertical axis offshore wind turbine. It is a 2MW fractional slotconcentrated winding permanent magnet synchronous polyphase machine, directly connected to bladeturbine. The principal purpose of this thesis consists in characterizing the alternator in order toevaluate its performances. The air gap permeance and the magnemotive force analytical modelingleads to study the air gap flux density and its harmonic content, which is particularly rich. Thecharacterization has also concerned the self and mutual inductance determination, which has requiredstalling the model by exploiting experimental measurements done at standstill. The particularity of thestudied machine leads us to consider an equivalent fictitious winding in order to determine the cyclicalinductances, necessary for the single-phase equivalent scheme establishment. Moreover, the machineback to back functioning has been studied and simulated. This functioning allows testing the machineitself and the other conversion chain subsystems, without using a second machine or blades to drivethe prototype rotor. It offers the possibility to test different types of operating points and to estimatethe power that can produce the studied machine: different operating points scenarios have beensimulated and parameters for tests have been defined. The back to back functioning of a classicalsynchronous machine has been also investigated, with an analytical modeling of the electromagneticphenomena and experimental tests.

Permanent magnet synchronous machine drives are used more often. Although, synchronous machines drive also suffer from possible faults. This thesis is focused on the detection of the three-phase synchronous motor winding faults and the detection of the drive control loop sensors' faults. Firstly, a model of the faulty winding of the motor is presented. Effects of the inter-turn short fault were analyzed. The model was experimentally verified by fault emulation on the test bench with an industrial synchronous motor. Inter-turn short fault detection algorithms are summarized. Three existing conventional winding fault methods based on signal processing of the stator voltage and stator current residuals were verified. Three new winding fault detection methods were developed by the author. These methods use a modified motor model and the extended Kalman filter state estimator. Practical implementation of the algorithms on a microcontroller is described and experimental results show the performance of the presented algorithms in different scenarios on test bench measurements. Highly related motor control loop sensors fault detection algorithms are also described. These algorithms are complementary to winding fault algorithms. The decision mechanism integrates outputs of sensor and winding fault detection algorithms and provides an overall drive fault diagnosis concept.

The diploma thesis focuses on manufacturing carbon fiber and epoxy composite material using filament winding method. Material properties of manufactured composite are ap-proximated using analytical and numerical homogenization models. Calculated material properties are applied to design and evaluate reserve factor of retaining sleeve for high speed brushless permanent magnet synchronous motor. Margin of safety of designed rotor is evaluated using composite failure criteria. Test stand for both static and dynamic testing is designed, static test stand is manufactured and assembled. Static strength test is carried out.

This thesis deals with the elaboration of The Permanent Magnet Synchronous Motor and the calculation of its parameters. In the first part, the construction and used permanent magnets of this motor are listed here. The next part of the thesis contains a short overview of the stator windings, the calculation of the winding factors and calculation of the basic parameters of the stator winding. The calculation of the magnetic induction in the air gap is also illustrated here. The result is recalculated by using the Carter factor and then the value of the first harmonics of air-gap flux density is determined. The result is compared with the analysis in the program FEMM. The next part of the thesis is creating a comprehensive overview of the machine using a replacement circuit diagram and phasor diagrams. Finally, the thesis contains model created in RMxprt and ANSYS Maxwell. The results of the model analysis are compared with the analytical calculation

Permanent magnet synchronous machine (PMSM) are widely used in many industrial applications. This thesis starts with familiarization with the properties and structure of each type of synchronous machines with permanent magnets. Subsequently there are described properties and possible division of AC winding types. Afterward analytical designs of four machines with two different types of winding were realized. These designs were compared by means of simulations using the RMxprt program and their properties were subsequently verified by method of finite element using the Maxwell 2D program. Evaluation and comparison in terms of utility properties for all designs of machines were performed at the conclusion of this thesis.

L’avènement des aimants permanents et les progrès récents dans l’électronique de puissance ont joué un rôle majeur dans l’évolution de la motorisation électrique des véhicules. Actuellement, les machines synchrones à aimants permanents (MSAP) grâce à leurs performances, et surtout leur efficacité énergétique, sont considérées comme les candidats idéaux pour les chaînes de traction des véhicules hybrides et électriques. Toutefois, en raison du vieillissement des matériaux, des défauts de fabrication ou des conditions de fonctionnement assez sévères, différents types de défauts sont capables de survenir dans les composants de la machine, ses organes de commande ou de mesure. Pour répondre aux exigences de sûreté, de fiabilité et de disponibilité, l’intégration d’une approche de surveillance et de diagnostic de défauts, dans le groupe motopropulseur électrique automobile, devient de plus en plus primordiale. Dans ce contexte, l’objectif de la thèse est de contribuer au diagnostic et à la caractérisation de défauts dans la MSAP par une analyse vibratoire. En premier temps, des approches analytiques de modélisation de la MSAP et des défauts : de court-circuit inter-spires, d’excentricité et de démagnétisation rotoriques serontproposées. L’intérêt majeur de tels modèles, dans le cadre du diagnostic, est d’étudier le comportement de la machine en présence de défauts étudiés afin d’en déduire les méthodes de détection les plus adaptées. En outre, des modèles numériques seront développés afin de les confronter aux parties magnétique et mécanique analytiques de la machine ainsi qu’au défaut de démagnétisation. Dans la phase d’analyse des impacts de défauts, nous allons nous focaliser sur les cas d’excentricité et de démagnétisation rotoriques. Les indicateurs de défauts seront extraits des représentations du signal vibratoire dans le temps et l’espace et de leurs transformées de Fourier, pour les cas de défauts simples et les cas de deux défauts combinés. Pour les cas simples, deux approches de localisation seront proposées : la première utilise le principe de tests statistiques et de tables de signatures, inspirée des méthodes de diagnostic à base de modèles, alors que la deuxième repose sur un banc de trois réseaux de neurones, où chacun est à une entrée et une sortie et destiné à localiser un type de défaut. Enfin, les performances des deux approches, en termes de robustesse et d’adaptabilité, seront comparées pour les mêmes ensembles de seuillage/d’apprentissage et de test. / The advent of new magnetic materials and recent advances in power electronics have played a major role in the progress of hybrid electric vehicles. Nowadays, permanent magnet synchronous machines (PMSM) thanks to their performances, especially their energy efficiency, are considered as ideal candidates for the traction chains of hybrid and electric vehicles. However, due to material aging, manufacturing defects or severe operating conditions, different types of faults are capable to occur in the machine components, its control or measuring devices. In order to ensure safety, reliability and availability, the integration of a fault diagnosis and condition monitoring approach in the automotive electrical powertrain system is becoming more and more important. In this context, the aim of the thesis is to contribute to the diagnosis and characterization of faults in the PMSM based on a vibration analysis. First, analytical modeling approaches for the PMSM and inter-turn short-circuits, eccentricity and rotor demagnetization faults will be proposed. The major interest of such models, in a diagnosis context, is to study the behavior of the machine in the presence of studied faults in order to deduce the most suitable detection methods. In addition, numerical models will be developed in order to validate the analytical magnetic and mechanical parts of the machine as well as the demagnetization fault. In the phase of fault impact analysis, we will focus on the cases of rotor eccentricity and demagnetization. The fault indicators will be extracted from the vibratory signal representations in time and space domains and their Fourier transforms, in the cases of single faults and the cases of two combined faults. For single fault cases, two diagnosis approaches will be proposed: the first uses the principle of statistical tests and fault signature tables, inspired by model-based diagnosis methods, while the second relies on a set of three neural networks, such as each one is with a single input and a single output and dedicated to isolate one type of fault. Finally, the performance of these two approaches, in terms of robustness and adaptability, will be compared for the same training and test sets.

Les Éoliennes à Entraînement Direct (ÉED) sont équipées de Générateurs Syn- chrones à Aimants Permanents (GSAP). Leurs trois plus courantes défaillances sont la dé- magnétisation, l’excentricité (statique, dynamique et mixte) et le court-circuit inter-tour. L’analyse de la signature du courant de la machine est souvent utilisée pour rechercher des problèmes du générateur, car ces altérations introduisent des harmoniques supplémen- taires dans les courants générés. La Transformée de Fourier Rapide (TFR) est utilisée pour calculer le spectre des courants. Cependant, la TFR permet de calculer l’ensemble du spec- tre, tandis que le nombre de défauts possible et le nombre d’harmoniques introduites sont faibles. L’algorithme de Goertzel, mis en oeuvre sous forme de filtre (le filtre de Goertzel), est présenté comme une alternative plus efficace au TFR. Le spectre des courants change avec la vitesse du vent, ce qui rend la détection plus difficile. Le Filtre de Kalman Étendu (FKÉ) est proposé comme solution. Le spectre de résidus, calcule entre les courants estimés et les courants générés, est constant, quelle que soit la vitesse du vent. Cependant, l’effet des défauts est visible dans leur spectre. Lors de l’utilisation de l’FKÉ, un défi consiste à estime la matrice de covariance pour le bruit du processus. Une nouvelle méthode était développée pour ça, qui n’utilise aucune de maîtrise du filtre. Les ÉED sont placés soit dans des zones éloignées, soit dans des villes. Pour la surveillance des ÉED, des dizaines ou des centaines de kilomètres de câbles sont nécessaires. Les Réseaux de Capteurs sans Fil (RCF) sont bien adaptés pour être utilisés dans l’infrastructure de communication des ÉED. RCF ont des coûts initiaux et d’entretien plus faibles et leurs installations sont rapides. De plus, ils peuvent compléter les réseaux câblés. Différentes technologies sans fil sont comparées : les technologies à grande surface, ainsi que les technologies à courte portée qui supportent des débits de données élevés. / Direct Drive Wind Turbines (DDWTs) are equipped with Permanent Magnet Syn- chronous Generators (PMSGs). Their three most common failures are demagnetization, ec- centricity (static, dynamic and mixed) and inter-turn short circuit. Machine Current Signa- ture Analysis is often used to look for generator problems, as these impairments introduce additional harmonics into the generated currents. The Fast Fourier Transform (FFT) is utilized to compute the spectrum of the currents. However, the FFT calculates the whole spectrum, while the number of possible faults and the number of introduced harmonics is low. The Goertzel algorithm, implemented as a filter (the Goertzel filter), is presented as a more efficient alternative to the FFT. The spectrum of the currents changes with the wind speed, and thus the detection is made more difficult. The Extended Kalman Filter (EKF) is proposed as a solution. The spectrum of the residuals, computed between the estimated and the generated current, is constant, regardless of the wind speed. However, the effect of the faults is visible in the spectrum. When using the EKF, one challenge is to find out the covariance matrix of the process noise. A new method was developed in this regard, which does not use any of the matrices of the filter. DDWTs are either placed in remote areas or in cities. For the monitoring of a DDWT, tens or hundreds of kilometers of cables are necessary. Wireless Sensor Networks (WSNs) are suited to be used in the communication infrastructure of DDWTs. WSNs have lower initial and maintenance costs, and they are quickly installed. Moreover, they can complement wired networks. Different wireless technologies are com- pared - both wide area ones, as well as short range technologies which support high data rates.

The stacked polyphase bridges (SPB) converter topology is investigated in the presentthesis as a fault-tolerant choice for permanent-magnet synchronous reluctance (PMSyn-Rel) motor control. Integrated motor drive systems are studied as they offer great benefitsfor propulsion applications. Moreover, the importance of a modular topology, like theSPB, for an electric powertrain is discussed. The latter consists of a number of seriesconnected, 3-phase 2-level inverter submodules that supply separate sets of windings ina multi-star motor. The specifications of building a four-board SPB setup are examined,while the challenges of an active voltage balancing controller are analyzed. The designprocess is explained step-by-step and the final printed circuit boards (PCBs) are presented.Furthermore, the significance of low electromagnetic interference design for a converterthat requires high speed communication is highlighted. Finally, the prototype is testedthoroughly and the expected fault-tolerant capabilities are validated on a PMSynRel motor. / I detta examensarbete unders¨ok SPB-omriktartopologin (stacked polyphase bridges converter)i termer av ett feltolerant elektriskt drivsystem f¨or en permamentmagnetassisteradsynkron reluktansmaskin (PMSynRel). SPB-omriktaren best°ar av ett antal seriekoppladetrefasomriktare av tv°aniv°atyp som, var och en, f¨orser effekt till en trefaslindningtillh¨orande en modul¨ar elmaskin av multifastyp. Specifikation, design och konstruktion aven SPB-omriktare med fyra seriekopplade moduler studeras. Designproceduren presenterasi en steg-f¨or-steg-process och de tillverkade kretskorten presenteras utf¨orligt. Kommunikationenmellan de olika kretskorten unders¨oks med s¨arskild tonvikt p°a l°ag elektromagnetiskinterferens vilket ¨ar n¨odv¨andigt om h¨og kommunikationshastighet skall kunnauppn°as. Den f¨ardigst¨allda prototypen har utv¨arderats experimentellt och kapaciteten f¨orfeltolerans har demonstrerats vid drift av en PMSynRel-maskin utrustad med en multifaslindning.

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