Les onduleurs sont des systèmes magnétiques créant un champ périodique permanent. Les sources de rayonnement synchrotron dites de « troisième génération » produisent du rayonnement accordable de haute intensité lorsque les particules relativistes sont accélérées dans ce champ magnétique. A une énergie donnée des électrons, l’émission est rayonnée à d’autant plus courte longueur d’onde que le champ magnétique créé est important et que la période est petite. Une première solution consiste à mettre les aimants sous vide. Le sujet de thèse consiste à améliorer les performances magnétiques de ce type d’onduleur de 30% en refroidissant le système magnétique. L’utilisation de la nuance d’aimant Pr2Fe14B permet de refroidir les aimants à la température de l’azote liquide ce qui simplifie beaucoup le système de refroidissement.Dans le chapitre I les caractéristiques magnétiques des onduleurs sont décrites, les différents types d’onduleurs sont présentés et l’état de l’art des onduleurs cryogénique est effectué. Dans le chapitre II plusieurs échantillons d’aimants permanents NdFeB et PrFeB de différents fournisseurs sont caractérisés. Deux prototypes d’onduleurs cryogéniques de 4 périodes, un avec la nuance NdFeB et l’autre avec la nuance PrFeB sont étudiés et réalisés afin de comparer et d’ajuster s’il y a besoin le modèle de simulation du système magnétique. La conception d’un onduleur cryogénique de 2 m utilisant la nuance d’aimant PrFeB en partant d’un onduleur sous vide de 2 m utilisant la nuance d’aimant SmCo est effectuée. La période de l’onduleur est optimisée et les forces magnétiques associées sont calculées. Dans le chapitre III la conception du châssis et des différentes pièces mécaniques est présentée. L’étude thermique qui inclut les apports de chaleur des différentes pièces et les calculs d’apport de chaleur du faisceau d’électrons pour tous les modes de remplissage du faisceau d’électrons et à différentes position dans l’anneau de stockage sont effectués. Le système de refroidissement est optimisé et la conception du circuit de refroidissement sur les poutres d’aimants est présentée. Dans le chapitre IV les différentes méthodes utilisées pour les mesures magnétiques sont décrites, les bancs de mesures magnétiques utilisés à SOLEIL sont présentés. La conception du banc de mesure magnétique intégré dans la chambre à vide afin de mesurer l’onduleur cryogénique à des températures cryogéniques est effectuée. Dans le chapitre V les différentes étapes de la construction de onduleur sous vide U20 (assemblage magnétique, corrections magnétique et « shimming », « magic finger », assemblage mécanique de la chambre à vide, l’installation et la caractérisation avec le faisceau) sont effectuées. Dans le chapitre VI les différentes étapes de la construction de l’onduleur cryogénique, le montage, l’ajustement et la calibration du banc de mesures à froid dans la chambre à vide de l’onduleur sont présentées. Les résultats de mesures magnétiques à froid sont comparés avec les mesures magnétiques de l’onduleur à température ambiante. La caractérisation de l’onduleur avec le faisceau d’électrons est effectuée et les perspectives d’amélioration de cet onduleur cryogénique sont proposées. / Undulators are magnetic systems which produce periodic magnetic field. Synchrotron radiation sources called third generation produce high intensity radiation when relativistic particles are accelerated in this magnetic field. The radiation is emitted at shorter wave length for high magnetic field and small period undulators. A first solution consists to integrate the magnetic system in a big vacuum chamber. The subject of the thesis is to improve the magnetic performance of an in vacuum undulator of 30 % by cooling down the magnetic system at cryogenic temperature. Using Pr2Fe14B permanent magnet allows cooling down directly to the liquid nitrogen temperature which simplified the cooling system.IN chapter I the magnetic characteristics of undulators are described, different types of undulators are presented and the state of the art of cryogenic undulator is given. In chapter II permanent magnet samples Pr2Fe14B Nd2Fe14B from different companies are characterised. Two four period prototypes, one with Pr2Fe14B and one with Nd2Fe14B have been assembled and measured to compare with the magnetic system simulation. The magnetic design of a full scale 2 m Pr2Fe14B undulator has been performed. The period of the undulator is optimised and the magnetic forces calculated. In chapter III the mechanical design of the carriage and different mechanical parts is presented. Thermal studies which include the dissipated power from different mechanical parts and from the electrons beam for all filling modes and different positions in SOLEIL storage ring. The cooling system is optimised and the design of the cooled girders is presented. In chapter IV the different magnetic measurements methods are described and the magnetic measurement bench used at SOLEIL presented. The design of magnetic bench installed in the vacuum chamber and dedicated to the magnetic measurement at cryogenic temperature is presented. In chapter V the different steps for the construction of an in-vacuum undulator (magnetic assembly, shimming, magic finger, mechanical assembly of the vacuum chamber, installation and commissioning with the electrons beam) are presented. In chapter VI the different steps of the constructing of a cryogenic undulator, the assembly and the ajustement of cryogenic temperature magnetic bench are described. The magnetic measurements of the undulator at cryogenic and room temperature are compared. The commissioning of the undulator with the electrons beam is presented and the perspectives to improve this cryogenic undulator are proposed.

Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2011. / Due to finite oil resources and its political and economical impact, a renewed interest in energy independence has compelled industry and government to pursue electric vehicle designs. The current worldwide research that is being conducted on drivetrain topologies for EVs, focus mainly on direct in-wheel drive, direct differential drive and fixed-gear differential drive topologies. Furthermore, the control strategy for these type of motor drives require a, so called, field-weakening operation in order to achieve acceptable performance characteristics for the vehicle. This thesis evaluates the use of a manual gearbox drivetrain topology and a radial flux air-cored permanent magnet (RFAPM) synchronous machine, without flux-weakening operation, as a traction drive application for EVs. For the purpose of this research study, a 2006 model Opel Corsa Lite is converted to a battery electric vehicle, and the Corsa is renamed to the E-Corsa. The Corsa is converted so that all the original functionality, boot space and space inside the vehicle are retained. The original 5-speed manual gearbox is used as drivetrain for the vehicle and a 40 kW, 70 Nm RFAPM traction drive is developed for the manual gearbox. A power electronic converter is designed for RFAPM traction drive and a Lithium ion (Li-ion) battery pack is used as energy source for the traction drive. The battery pack is mounted partially in the front and partially in the back of the vehicle to maintain an even weight distribution in the vehicle.

A determinação das principais propriedades magnéticas de um ímã permanente geralmente requer sistemas de medição sofisticados e custosos. Este trabalho analisa e propõe um sistema de caracterização de ímãs permanentes de Terras Raras e Cerâmicos à temperatura ambiente de baixo custo e de implementação mais simples. Para isso, o Histerisímetro de Entreferro Variável, HEV, é concebido e estudado. Ele consiste de um circuito magnético formado pelo ímã permanente sob caracterização, uma culatra de aço, um entreferro variável, bobinas de magnetização e desmagnetização de baixa potência, uma sonda de efeito Hall com seu respectivo gaussímetro, um fluxímetro com sua bobina exploradora, o circuito eletrônico de comando das bobinas de excitação e a interface a um sistema de instrumentação virtual. Para demonstrar os desenvolvimentos do trabalho são apresentados o estado da arte da caracterização dos ímãs permanentes, conceitos básicos de magnetismo em relação aos ímãs permanentes, instrumentação necessária para sua caracterização, a concepção e modelagem do HEV, os resultados dos testes realizados e uma abrangente análise de suas incertezas. Com isso é demonstrado que o Histerisímetro de Entreferro Variável é uma alternativa de caracterização de ímãs permanentes com desmagnetização linear com incertezas dentro do que é definido pela norma. / The determination of the main magnetic properties of permanent magnets usually requires sophisticated and expensive measuring systems. This work analyses and proposes a low-cost system for the characterization of Rare Earth and Ceramics permanent magnets at room temperature with simpler implementation. It comprehends a magnetic circuit with the permanent magnet under test, a steel yoke with appropriate pole pieces, a variable air gap, low power magnetization and demagnetization coils, a Hall Effect probe with its respective gaussmeter, a fluxmeter with its own search coil, a coil driver electronic circuit and a virtual instrumentation system (computer plus graphical interface software). To demonstrate the developments of the work, it is presented the state of the art of permanent magnets characterization, basic concepts of magnetism related to permanent magnets, the instrumentation required for its characterization, the HEV design and modeling, the results of the tests and a comprehensive analysis of related uncertainties. Thus, it is shown that the Variable Gap Hysteresimeter is an alternative characterization system for linear demagnetization permanent magnets with uncertainties within those defined by the standards.

A determinação das principais propriedades magnéticas de um ímã permanente geralmente requer sistemas de medição sofisticados e custosos. Este trabalho analisa e propõe um sistema de caracterização de ímãs permanentes de Terras Raras e Cerâmicos à temperatura ambiente de baixo custo e de implementação mais simples. Para isso, o Histerisímetro de Entreferro Variável, HEV, é concebido e estudado. Ele consiste de um circuito magnético formado pelo ímã permanente sob caracterização, uma culatra de aço, um entreferro variável, bobinas de magnetização e desmagnetização de baixa potência, uma sonda de efeito Hall com seu respectivo gaussímetro, um fluxímetro com sua bobina exploradora, o circuito eletrônico de comando das bobinas de excitação e a interface a um sistema de instrumentação virtual. Para demonstrar os desenvolvimentos do trabalho são apresentados o estado da arte da caracterização dos ímãs permanentes, conceitos básicos de magnetismo em relação aos ímãs permanentes, instrumentação necessária para sua caracterização, a concepção e modelagem do HEV, os resultados dos testes realizados e uma abrangente análise de suas incertezas. Com isso é demonstrado que o Histerisímetro de Entreferro Variável é uma alternativa de caracterização de ímãs permanentes com desmagnetização linear com incertezas dentro do que é definido pela norma. / The determination of the main magnetic properties of permanent magnets usually requires sophisticated and expensive measuring systems. This work analyses and proposes a low-cost system for the characterization of Rare Earth and Ceramics permanent magnets at room temperature with simpler implementation. It comprehends a magnetic circuit with the permanent magnet under test, a steel yoke with appropriate pole pieces, a variable air gap, low power magnetization and demagnetization coils, a Hall Effect probe with its respective gaussmeter, a fluxmeter with its own search coil, a coil driver electronic circuit and a virtual instrumentation system (computer plus graphical interface software). To demonstrate the developments of the work, it is presented the state of the art of permanent magnets characterization, basic concepts of magnetism related to permanent magnets, the instrumentation required for its characterization, the HEV design and modeling, the results of the tests and a comprehensive analysis of related uncertainties. Thus, it is shown that the Variable Gap Hysteresimeter is an alternative characterization system for linear demagnetization permanent magnets with uncertainties within those defined by the standards.

A determinação das principais propriedades magnéticas de um ímã permanente geralmente requer sistemas de medição sofisticados e custosos. Este trabalho analisa e propõe um sistema de caracterização de ímãs permanentes de Terras Raras e Cerâmicos à temperatura ambiente de baixo custo e de implementação mais simples. Para isso, o Histerisímetro de Entreferro Variável, HEV, é concebido e estudado. Ele consiste de um circuito magnético formado pelo ímã permanente sob caracterização, uma culatra de aço, um entreferro variável, bobinas de magnetização e desmagnetização de baixa potência, uma sonda de efeito Hall com seu respectivo gaussímetro, um fluxímetro com sua bobina exploradora, o circuito eletrônico de comando das bobinas de excitação e a interface a um sistema de instrumentação virtual. Para demonstrar os desenvolvimentos do trabalho são apresentados o estado da arte da caracterização dos ímãs permanentes, conceitos básicos de magnetismo em relação aos ímãs permanentes, instrumentação necessária para sua caracterização, a concepção e modelagem do HEV, os resultados dos testes realizados e uma abrangente análise de suas incertezas. Com isso é demonstrado que o Histerisímetro de Entreferro Variável é uma alternativa de caracterização de ímãs permanentes com desmagnetização linear com incertezas dentro do que é definido pela norma. / The determination of the main magnetic properties of permanent magnets usually requires sophisticated and expensive measuring systems. This work analyses and proposes a low-cost system for the characterization of Rare Earth and Ceramics permanent magnets at room temperature with simpler implementation. It comprehends a magnetic circuit with the permanent magnet under test, a steel yoke with appropriate pole pieces, a variable air gap, low power magnetization and demagnetization coils, a Hall Effect probe with its respective gaussmeter, a fluxmeter with its own search coil, a coil driver electronic circuit and a virtual instrumentation system (computer plus graphical interface software). To demonstrate the developments of the work, it is presented the state of the art of permanent magnets characterization, basic concepts of magnetism related to permanent magnets, the instrumentation required for its characterization, the HEV design and modeling, the results of the tests and a comprehensive analysis of related uncertainties. Thus, it is shown that the Variable Gap Hysteresimeter is an alternative characterization system for linear demagnetization permanent magnets with uncertainties within those defined by the standards.

This thesis is a study on an unconventional slow speed direct drive permanent magnet (PM) generator. Unlike a standard permanent magnet synchronous generator (PMSG) which has the copper coils wound around iron teeth, the work in this thesis will present a generator where the copper coils are directly mounted on the stator which eliminates the slots and teeth in the generator. By having a slotless design it is possible to eliminate cogging torque, iron losses in teeth and achieve a lightweight design. These characteristics can prove useful when developing generators for an application such as wind turbines, or more specifically vertical axis wind turbines (VAWTs) in remote areas where weight and serviceability is of concern. This thesis consists of two main parts where the main focus was on the design and simulation of slotless generators. The second part of the thesis was to investigate an available slotless axial flux machine. For the simulations, three different models were created in 2D using CAD software. Two of the models were double-rotor slotless generators and one was a single rotor variant. The electromagnetic properties of these models were analysed using FEMM and COMSOL. The results showed that the double rotor variant with the smaller magnets were more favourable considering the price of magnets and no iron core losses. The experimental results of the axial flux machine gave insight into the construction of commercially available axial slotless generators which could be used to further analyse these types of machines.

No description available.

This thesis studies wave energy converters developed at Uppsala University. The wave energy converters are of point absorbing type with direct driven linear generators. The aim has been to study generator design with closed stator slots as well as offshore experimental studies. By closing the stator slots, the harmonic content in the magnetic flux density is reduced and as a result the cogging forces in the generator are reduced as well. By reducing these forces, the noise and vibrations from the generator can be lowered. The studies have shown a significant reduction in the cogging forces in the generator. Moreover, by closing the slots, the magnetic flux finds a short-cut through the closed slots and will lower the magnetic flux linking the windings. The experimental studies have focused on the motion of the translator. The weight of the translator has a significant impact on the power absorption, especially in the downward motion. Two different experiments have been studied with two different translator weights. The results show that with a higher translator weight the power absorption is more evenly produced between the upward and downward motion as was expected from the simulation models. Furthermore, studies on the influence of the changing active area have been conducted which show some benefits with a changing active area during the downward motion. The experimental results also indicate snatch-loads for the wave energy converter with a lower translator weight. Within this thesis results from a comparative study between two WECs with almost identical properties have been presented. The generators electrical properties and the buoy volumes are the same, but with different buoy heights and diameters. Moreover, experimental studies including the conversion from AC to DC have been achieved. The work in this thesis is part of a larger wave power project at Uppsala University. The project studies the whole process from the energy absorption from the waves to the connection to the electrical grid. The project has a test-site at the west coast of Sweden near the town of Lysekil, where wave energy systems have been studied since 2004.

Thesis (PhD (Electrical and Electronic Engineering))--University of Stellenbosch, 2009.

Η παρούσα διπλωματική εργασία πραγματεύεται τη μελέτη και προσομοίωση ενός τμήματος μιας ανεμογεννήτριας η οποία μελλοντικά θα συνδεθεί στο τριφασικό δίκτυο. Η εργασία αυτή εκπονήθηκε στο Εργαστήριο Ηλεκτρομηχανικής Μετατροπής Ενέργειας του Τμήματος Ηλεκτρολόγων Μηχανικών και Τεχνολογίας Υπολογιστών της Πολυτεχνικής Σχολής του Πανεπιστημίου Πατρών. Συγκεκριμένα μελετήθηκε και προσομοιώθηκε μια σύγχρονη μηχανή μόνιμου μαγνήτη, η οποία θα αποτελέσει τη γεννήτρια της διάταξης, η οποία συνδέεται στην έξοδο με έναν τριφασικό μετατροπέα. Σκοπός του μετατροπέα είναι η μετατροπή της εναλλασσόμενης τάσης που δέχεται στην είσοδο του, και προέρχεται από την τάση εξ επαγωγής στο στάτη της μηχανής, σε μια συνεχή τάση στην έξοδο του μετατροπέα, δηλαδή πρόκειται για έναν ανορθωτή. Επιπλέον ο μετατροπέας αυτός είναι ένας μετατροπέας ανύψωσης της τάσης, δηλαδή ένας μετατροπέας τύπου boost. Η ανύψωση αυτή γίνεται έχοντας ως δεδομένο ότι ο απώτερος σκοπός μας είναι η σύνδεση της ανεμογεννήτριας στο δίκτυο των 220 V. Συγκεκριμένα η συνεχής τάση που θα μας δώσει ο ανορθωτής προορίζεται να μετατραπεί εκ νέου σε εναλλασσόμενη, από μια διάταξη αντιστροφέα, ώστε τελικά να προκύψει μια κατάλληλη τάση για σύνδεση της ανεμογεννήτριας στο δίκτυο. Ύστερα από μελέτη διαφόρων ανορθωτικών διατάξεων επιλέχθηκε να χρησιμοποιηθεί στην προσομοίωσή ο τριφασικός ανορθωτής ανύψωσης ενός διακοπτικού στοιχείου. Ο διακόπτης του ανορθωτή παλμοδοτήθηκε με την τεχνική της Διαμόρφωσης Εύρους των Παλμών (Pulse Width Modulation-P.W.M) ενώ ένας PI ελεγκτής χρησιμοποιήθηκε προκειμένου να προσαρμοστεί η συνεχής τάση εξόδου του μετατροπέα στις απαιτήσεις του δικτύου. Η μηχανή που μελετήθηκε είναι μια σύγχρονη γεννήτρια μόνιμου μαγνήτη οχτώ πόλων, ονομαστικής ισχύος 660 W, ονομαστικής τάσης 48 V και ονομαστικής ταχύτητας 3000 rpm. Για την εξομοίωσή της χρησιμοποιήθηκε το λογισμικό Οpera σε δύο διαστάσεις (2d). Στο περιβάλλον σχεδίασης κυκλωμάτων του ίδιου προγράμματος σχεδιάστηκε σε πρώτη φάση ο τριφασικός ανορθωτής και έτσι έγινε εξαγωγή των αποτελεσμάτων για το σύστημα ανοιχτού βρόχου. Στη συνέχεια έγινε διασύνδεση του λογισμικού Opera με το Simulink του Matlab ώστε να επιτευχθεί έλεγχος κλειστού βρόχου αλλά και εκ νέου εξαγωγή των αποτελεσμάτων ανοιχτού βρόχου, ενώ παράλληλα πραγματοποιήθηκε εξομοίωση του συστήματος μηχανής μετατροπέα εξ ολοκλήρου στο Simulink του Matlab με σκοπό την επιλογή των βέλτιστων παραμέτρων του PI ελεγκτή. / This thesis deals with the design and simulation of a section of a wind turbine which will in future be connected to the three-phase network. The thesis was accomplished in Electromechanical Energy Conversion Laboratory , Department of Electrical and Computer Engineering of the University of Patras. Specifically, it was studied and simulated a permanent magnet synchronous machine , which is connected to the output with a three-phase converter. The purpose of the converter is to convert the alternating voltage it receives at its entrance, and it comes from the induced voltage in the stator of the machine , into a constant output voltage. Furthermore, the converter’s purpose is to elevate the voltage as it is a boost converter. The voltage should be elevated because the ultimate goal is to connect the wind turbine to the grid of 220 V. Specifically, the dc output voltage of the rectifier, is intended to be converted back into the appropriate ac voltage in order to connect the wind turbine to the grid. Having studying various rectifier’s topologies, it had been chosen the three-phase single switch boost rectifier. The Pulse Width Modulation (PWM) was chosen for the rectifier’s switch and a PI controller was used to adjust the DC output voltage of the converter to the grid . The studied machine is a permanent magnet synchronous generator with eight poles , rated power 660 W, 48 V nominal voltage and rated speed of 3000 rpm. For the simulation, it was used Opera F.E.M. software in two dimensions (2d). In the same program’s design environment was designed the three-phase rectifier and the results for the open loop system were taken. Then, in order to achieve closed – loop control, the rectifier model was created in the “Matlab/Simulink” environment and the machine F.E.M. model was created in “Opera-2D” environment and they were combined into a composite model. By using this interface we managed to re export also results for the open loop system in order to compare the new results with the ones when only the Opera (machine-rectifier) model was used. Finally, the system machine – rectifier was simulated entirely in Simulink of Matlab in order to select the optimum parameters of the PI controller.