With the rapid growth of air travel, concerns about the emissions of greenhouse gas emissions resulting from the air transportation sector are growing. Although the current battery technologies might not be adequate for all-electric regional aircraft, the energy density of the current battery technologies could be adequate to electrify light-sport aircraft used for training and recreation. Due to the nature of the propeller load and noise isolation of the cabin, switched reluctance motors can be an excellent candidate for the propulsion system of electrified light-sport aircraft. The proposed SRM is designed to replace a 70 kW permanent magnet synchronous motor used in the aerospace industry with similar volume constraints and operational requirements. In order to meet the high-power density requirements of this application, a design framework is proposed which includes several layers of the design process. The design objectifies are the average torque, torque ripple, and radial forces by integrating the control and geometry design into the proposed framework. A comprehensive design process is carried out with the proposed framework, and a detailed coil design process is performed. The rotor cut-outs are designed to reduce the weight of the motor. The thermal performance of the motor has been analyzed for the calculated motor losses and the cooling system constraints. / Thesis / Master of Applied Science (MASc)

Este trabalho se insere num contexto de desenvolvimento da capacitação para aplicações de motores de relutância chaveados, com ênfase aos aspectos eletromagnéticos do acionamento. Inicialmente, são apresentados os principais aspectos construtivos do motor e de funcionamento do seu conversor. São discutidos os fluxos de energia do acionamento e sao apresentadas as suas características operacionais, bem como as possibilidades para o seu controle. Foi desenvolvida uma metodologia de projeto embasada numa formulação empírica e no método dos elementos finitos, implementado através do programa flux2d. Desta forma, foi projetado um protótipo para desenvolver meio newton-metro a três mil rotações por minuto. A formulação empírica baseia-se na adoção de diversas hipóteses simplificadoras do circuito ferromagnético. O método dos elementos finitos foi empregado com a finalidade da obtenção de um refinamento do dimensionamento do motor. O protótipo projetado foi fabricado e testado. Os objetivos dos ensaios foram a confrontação com os diversos valores calculados no projeto e a verificação do seu desempenho em diversas condições de carga. Finalizando o trabalho, os resultados obtidos são analisados, ressaltando-se os aspectos relevantes ocorridos durante o seu desenvolvimento. São também apresentadas, as atividades subsequêntes previstas. / This work is related to the development activities of switched reluctance motors, mainly on their electromagnetic characteristics. The motor\'s basic construction features and the converter\'s operation characteristics are showed, as well as, the energy flows, performance aspects and the effects of the control parameters. The principal elements of motor desigm are discussed. A method of design is developed based on empirical formulas and on finite elements method (using the software FLUX2D). Thus, a prototype was designed with ratings of 0,5 Nm at 3000 rpm. The empirical formulas are developed on a simplified model of the motor and taking into account the referred author\'s experience. The finite elements method was used with the aim of getting a design refinement, as well as, the static torque characteristics, inductances and flux as a function of rotor position and current. The prototype was built and tested. The tests were conducted to compare the actual with the designed parameters and to evaluate the performance characteristics. Finally, the results are analysed and the main facts observed during the development of the work are reported. The next planned activities are also showed.

Este trabalho se insere num contexto de desenvolvimento da capacitação para aplicações de motores de relutância chaveados, com ênfase aos aspectos eletromagnéticos do acionamento. Inicialmente, são apresentados os principais aspectos construtivos do motor e de funcionamento do seu conversor. São discutidos os fluxos de energia do acionamento e sao apresentadas as suas características operacionais, bem como as possibilidades para o seu controle. Foi desenvolvida uma metodologia de projeto embasada numa formulação empírica e no método dos elementos finitos, implementado através do programa flux2d. Desta forma, foi projetado um protótipo para desenvolver meio newton-metro a três mil rotações por minuto. A formulação empírica baseia-se na adoção de diversas hipóteses simplificadoras do circuito ferromagnético. O método dos elementos finitos foi empregado com a finalidade da obtenção de um refinamento do dimensionamento do motor. O protótipo projetado foi fabricado e testado. Os objetivos dos ensaios foram a confrontação com os diversos valores calculados no projeto e a verificação do seu desempenho em diversas condições de carga. Finalizando o trabalho, os resultados obtidos são analisados, ressaltando-se os aspectos relevantes ocorridos durante o seu desenvolvimento. São também apresentadas, as atividades subsequêntes previstas. / This work is related to the development activities of switched reluctance motors, mainly on their electromagnetic characteristics. The motor\'s basic construction features and the converter\'s operation characteristics are showed, as well as, the energy flows, performance aspects and the effects of the control parameters. The principal elements of motor desigm are discussed. A method of design is developed based on empirical formulas and on finite elements method (using the software FLUX2D). Thus, a prototype was designed with ratings of 0,5 Nm at 3000 rpm. The empirical formulas are developed on a simplified model of the motor and taking into account the referred author\'s experience. The finite elements method was used with the aim of getting a design refinement, as well as, the static torque characteristics, inductances and flux as a function of rotor position and current. The prototype was built and tested. The tests were conducted to compare the actual with the designed parameters and to evaluate the performance characteristics. Finally, the results are analysed and the main facts observed during the development of the work are reported. The next planned activities are also showed.

Fundação de Amparo a Pesquisa do Estado de Minas Gerais / The subject of this work is to present a switched reluctance machine (SRM) driver capable to control the machine as a motor/generator, allowing the transition between the modes of operation while the machine is running. Six load voltage control strategies developed to be applied to a switched reluctance generator was performed, being that the strategies AV2, TBV, Hi and AMV was developed in this work. A SRM simulation able to represent the machine as a motor/generator was implemented and the results were presented. The load voltage strategies showed in this work was tested through simulations and the results indicate that the strategy called AV2 was the best one, providing a better utilization of the mechanical energy from the primary source. A prototype was assembled and the experimental results showed that the machine operating as a motor/generator operate properly and all the load voltage strategies developed to switched reluctance generator kept the voltage on the load near to the reference value confirming the functionality of the strategies. / Este trabalho tem como objetivo apresentar um acionamento capaz de controlar a máquina de relutância variável (MRV) como motor e como gerador, permitindo a transição de modos de operação com a máquina girando. Seis técnicas de controle de tensão na carga da máquina operando como gerador foram implementadas, sendo que as estratégias AV2, TBV, Hi e AMV foram desenvolvidas neste trabalho. Uma simulação da MRV capaz de representar a operação da máquina como motor/gerador foi desenvolvida e os resultados foram apresentados. As estratégias de controle de tensão na carga foram testadas através de simulação. Comparações entre as mesmas demonstraram que a estratégia AV2 é a que proporciona maior geração de energia elétrica, demonstrando a importância de se adicionar uma etapa de roda livre ao controle do GRV com malha fechada de tensão na carga. Um protótipo foi construído no laboratório utilizando DSP e resultados experimentais da máquina operando como motor/gerador, assim como resultados do GRV controlado pelas estratégias de controle de tensão na carga foram apresentados e discutidos. / Doutor em Ciências

This work shows a contribution to the study of the Switched Reluctance Machine driven as a generator to connecting in the grid to inject active power. The main objective is show the Switched Reluctance Generator behavior under various operating conditions, as well as the development of an electronic converter to connect it to the low voltage grid. Thus, it presents a mathematical model for the Switching Reluctance Generator which includes the magnetic circuit saturation and a computational model for analyzing steady state and transient. Also it is presented a strategy of generated voltage control by the magnetization angle variation acting only in the top switch of the Asymmetrical Half Bridge converter. An intermediate stage was added in the switching control strategy to reduce the energy amount provided by the excitation source and get better utilization of electromechanical conversion. A detailed description of the control system equations of the DC-AC stage, PLL algorithm and design of injected current compensator are presented and discussed. Finally, it was constructed in laboratory a experimental platform for verification of the theoretical and simulation. / Este trabalho apresenta uma contribuição ao estudo da Máquina a Relutância Variável acionada como gerador para conexão com rede elétrica e injeção de potência ativa. O objetivo principal é apresentar o comportamento do Gerador a Relutância Variável sob diversas condições de operação, bem como o desenvolvimento de um conversor eletrônico para a sua conexão a rede elétrica de baixa tensão. Assim, é apresentado um modelo matemático para o Gerador a Relutância Variável que contempla a saturação do circuito magnético e um modelo computacional para análise em regime permanente e transitório. Também é apresentada uma estratégia de controle da tensão gerada através da variação do ângulo de magnetização atuando apenas nas chaves superiores do conversor assimétrico Half Bridge. Uma etapa intermediária no chaveamento foi acrescentada à estratégia de controle para diminuir a quantidade de energia fornecida pela fonte de excitação e obter melhor aproveitamento da conversão eletromecânica. Uma descrição detalhada do equacionamento do sistema de controle do estágio CC-CA, do algoritmo de PLL e projeto do compensador da corrente injetada são apresentados e discutidos. Por fim, construiu-se uma plataforma experimental em laboratório para a comprovação dos estudos teóricos e de simulação. / Doutor em Ciências

Submitted by Renata Lopes (renatasil82@gmail.com) on 2018-05-25T12:16:21Z No. of bitstreams: 1 lucasalvesdealmeida.pdf: 7514122 bytes, checksum: a0029ec07180541f754e98112ec47b6b (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2018-06-14T11:52:17Z (GMT) No. of bitstreams: 1 lucasalvesdealmeida.pdf: 7514122 bytes, checksum: a0029ec07180541f754e98112ec47b6b (MD5) / Made available in DSpace on 2018-06-14T11:52:17Z (GMT). No. of bitstreams: 1 lucasalvesdealmeida.pdf: 7514122 bytes, checksum: a0029ec07180541f754e98112ec47b6b (MD5) Previous issue date: 2018-02-27 / Sistemas eletromecânicos são de grande importância atualmente, e a procura por maior eficiência e desempenho aliados a um menor custo justificam a busca por alternativas tanto em topologia quanto no controle e acionamento de tais sistemas. A máquina de relutância chaveada é capaz de cumprir estes requisitos e tem despertado o interesse de pesquisadores e empresas nos últimos anos, emergindo como uma alternativa viável em diversas aplicações. Porém, esta máquina possui características singulares. Por conta de sua estrutura duplamente saliente, seu funcionamento correto depende da aplicação de pulsos de corrente por determinados intervalos de tempo, e na sequência correta, seus parâmetros são variáveis no tempo, apresentando um comportamento com características não-lineares. Tais particularidades fazem com que seja difícil controlar o torque destas máquinas, as quais possuem a tendência de apresentar altas oscilações durante a mudança da excitação de cada fase. Este trabalho tem por objetivo contribuir com o estudo da modelagem e do acionamento de uma máquina de relutância chaveada. É apresentada sua modelagem matemática e um modelo de simulação que leva em consideração as não linearidades existentes. Em seguida são apresentadas técnicas de controle de corrente que incluem um regulador de histerese, um controlador PI e um controlador por modos deslizantes. Também é utilizado um método capaz de determinar o momento em que cada fase deve ser acionada, baseado no ângulo do rotor, e uma técnica de variação dos ângulos de acionamento de maneira dinâmica, usados em conjunto com os controladores propostos. O trabalho também caracteriza e apresenta as funções de divisão de torque como uma maneira de reduzir drasticamente as oscilações de torque. São apresentadas as operações como motor e como gerador, bem como um exemplo de aplicação de modo a ilustrar ambos os modos de operação. / Electromechanical systems have a huge relevance nowadays, and seeking for improvements in efficiency and performance at the lowest cost make valid to identify topological and control alternatives of these systems. The switched reluctance machine is capable to fulfill such requirements and emerges as an interesting field of research. Academics and industrial works shows that it is a promising alternative in several applications. However, this machine presents unique characteristics, like the doubly salient structure, the necessity to apply phase currents in a sequence determined by the stator/rotor pole ratio, its time variantparameters,andthestrongnonlinearcharacteristics. Suchsingularitiesmaketorque control hard, as it tends to present high ripples and makes a lot of noise. This thesis aims to contribute on switched reluctance machine modeling and drive system. A mathematical model is presented, and also a simulation model that accounts for nonlinearities, making possible to simulate the machine accurately in a computational environment. A hysteresis regulator, a PI controller and a sliding mode controller are designed and simulated. An algorithm to determine when each phase should be excited based on rotor angle is used, and a technique to change such firing angles dynamically is developed that can be used along with current control methods presented. The work also defines and presents torque sharing functions as a way to greatly reduce torque ripple. Motor and generator operation are contemplated, and both modes are illustrated in an application example.

The awareness of the human responsibility in global warming has led to various private and public initiatives to reduce the emission of greenhouse gases, up to international level. In this context the development of renewable technologies in two sectors having an important ecological footprint, i.e. production of electricity and transportation, is targeted.In the firstly mentioned sector, the progression of wind energy is at present the most rapid among all renewable energies. But wind turbines still suffer from a global lack of reliability and accessibility compared to classical power plants, leading to potentially important production losses and repair costs. The first part of the present work focuses on the improvement of the electrical chain reliability by the combination of an estimator and a fault-detection algorithm to achieve sensor-fault tolerance, taking benefit from the already available measurement redundancies on doubly-fed-induction-machine (DFIG) drives.Estimators and sensor-fault detection and isolation (FDI) in DFIGs have been the object of many research papers. However, most of them only consider one unique type of measurement and only a few works consider magnetic saturation. A new combination of a closed-loop observer with a cumulative-sum-based FDI technique, considering magnetic saturation and using limited computational resources is proposed here to estimate electromagnetic torque, rotor currents and position for sensor-fault detection and tolerance. This algorithm is then validated in steady state and in case of moderate transients, unbalanced conditions and misestimation of DFIG parameters. The estimator can also start on the fly during the start-up process of the generator.In the transportation sector, new hybrid and full-electric vehicles start to be visible on the roads, but still need important technological improvements in terms of autonomy, performances, but also produced noise and vibrations. The objectives of the second part of this doctoral thesis are related to this last challenge and consist of the experimental investigation of noise, vibration and harshness (NVH) aspects of an 8/6 switched-reluctance machine (SRM) designed for an electrical vehicle (EV).The NVH issues of SRMs, limiting their usage in automotive and other domains, have been the subject of various papers. However, most of them focus on modal analysis or detailed phenomena, while a global evaluation of NVH aspects of SRMs in normal working conditions is rarely made, as well as the use of reproducible sound metrics. A global and relatively fast experimental method to assess the evolution of noise and vibration is proposed. Tests are performed in transient regime, using continuously varying working conditions when possible, for the excitation of a large band of frequencies. The resulting current, radial vibration and acoustic noise are presented as spectrograms for an easy distinction of affected and unaffected frequencies and compared with the associated loudness and sharpness.Furthermore, the implementation of a new faster-sampled current-hysteresis controller has allowed to improve the quality of the control and of the acoustic noise by reducing the current-ripple amplitude and the excitation of resonances. The various tests show that the switching frequency has to be high enough to avoid exciting the ovalization mode of the SRM, but not too high to avoid producing a too sharp noise. The ripple amplitude also has to be considered to limit the loudness. Therefore, soft chopping, or a reduced DC-bus voltage at low speeds, has to be preferred with a relative small hysteresis bandwidth. Finally, the case of an open-phase fault has been investigated showing amplified even current orders in the vibration and acoustic-noise plots. / La prise de conscience de la responsabilité humaine dans le réchauffement climatique est à la source de nombreuses initiatives publiques et privées parfois internationales pour réduire les émissions de gaz à effet de serre. Dans ce contexte, le développement de technologies durables dans deux secteurs à forte empreinte écologique est visé: la production d'énergie électrique et les transports. Dans le premier secteur, la progression de l'éolien est à présent la plus rapide parmi toutes les énergies renouvelables. Cependant, les éoliennes souffrent d'un manque global de fiabilité et d'accessibilité par rapport aux centrales électriques classiques, ce qui conduit potentiellement à des pertes de production et des coûts de réparation importants. La première partie de ce travail se focalise sur l'amélioration de la chaîne électrique en la rendant tolérante aux défauts de capteurs au moyen de la combinaison d'un estimateur et d'un algorithme de détection de défauts, tirant avantage de la redondance de mesures déjà présente sur les entraînements à machines asynchrones à double alimentation (MADA). Les estimateurs et la détection et l'isolation de défauts de capteurs sur les MADA a fait l'objet de nombreuses publications scientifiques. Cependant, la plupart d'entre elles considèrent un seul type de mesure et peu de travaux prennent en compte la saturation magnétique. Une nouvelle combinaison d'un observateur et d'un algorithme de détection de défauts de type ‘CUSUM', considérant la saturation magnétique et nécessitant une puissance de calcul limitée, est proposée dans cette thèse pour l'estimation du couple électromagnétique, des courants et de la position rotoriques en vue d'obtenir la tolérance aux défauts de capteurs. Cet algorithme est validé en régime permanent et cas de transitoires modérés, de tensions du réseau déséquilibrées et d'erreurs d'estimation des paramètres de laMADA. L'estimateur est aussi capable de démarrer seul lors du démarrage de la génératrice. Dans le secteur des transports, des véhicules hybrides et électriques commencent à être visibles sur les routes, malgré que des progrès technologiques importants en termes d'autonomie, de performances, mais aussi de bruits et vibrations soient encore nécessaires pour une utilisation plus intensive. L'objectif de la deuxième partie de cette thèse se rapporte à ce dernier défi et consiste à analyser les aspects acoustiques et vibratoires d'une machine à réluctance variable 8/6 conçue pour propulser un véhicule électrique. Ces problèmes acoustiques et vibratoires, qui limitent notamment l'usage de telles machines dans des applications de propulsion, ont été l'objet de divers articles scientifiques. Cependant, la plupart d'entre eux sont focalisés sur des analyses modales ou de phénomènes particuliers, alors qu'une évaluation globale des problèmes de bruit et de vibration des machines à réluctance variable en conditions normales de fonctionnement est rarement proposée, de même que l'utilisation de critères de qualité sonore. Une méthode expérimentale globale et relativement rapide pour évaluer l'évolution du bruit et des vibrations est proposée dans ce travail. Les essais sont réalisés en régime transitoire pour exciter une large bande de fréquences et en faisant varier continuellement, quand cela est possible, les conditions de fonctionnement. Les courants, vibrations radiales et bruits acoustiques résultants sont présentés sous formes de cartographies couleur pour une distinction aisée des fréquences affectées et non-affectées et comparés aux niveaux calculés de bruyance et d'acuité correspondants. Par ailleurs, la mise en place d'un nouveau régulateur à hystérèse en courant à plus grande fréquence d'échantillonnage a permis d'améliorer la qualité de la commande et du bruit acoustique associé en réduisant l'amplitude des oscillations de courant et l'excitation des fréquences de résonance. Les essais montrent que la fréquence de commutation doit être suffisamment élevée pour éviter l'excitation du mode d'ovalisation de la machine, mais pas trop pour éviter une trop grande acuité du son produit. L'amplitude des oscillations doit aussi être considérée pour limiter la bruyance. En conséquence, une commande en ‘soft chopping', ou une tension réduite du bus continu à basse vitesse, doit être combinée à une bande d'hystérèse relativement faible. Enfin, le cas d'un défaut de phase ouverte a été étudié et a montré une amplification des ordres pairs du courant dans les spectres vibratoires et acoustiques. / De bewustwording van de menselijke verantwoordelijkheid in de opwarming van de aarde heeft tot verschillende private en publieke initiatieven geleid om de uitstoot van broeikasgassen te verminderen. In deze context is de ontwikkeling van hernieuwbare technologieën hoofdzakelijk gericht op twee sectoren met een belangrijke ecologische impact: elektriciteitsproductie en transport.In de eerste sector ontwikkelt windenergie zich op dit moment sneller dan alle andere hernieuwbare energieën. Maar windturbines lijden nog steeds aan een gebrek aan betrouwbaarheid en toegankelijkheid, en dus aan potentieel hogere productieverliezen en herstelkosten, als ze met klassieke krachtcentrales worden vergeleken. In het eerste deel van deze doctoraatsthesis wordt op de verbetering van de elektrische keten geconcentreerd door de combinatie van een schatter en een foutdetectie- en -isolatiealgoritme (FDI-algoritme) om sensorfouttolerantie te verkrijgen dankzij de reeds aanwezige meetovertolligheid op dubbelgevoede inductiemachine (DFIG) aandrijvingen.Schatters en sensor-FDI-algoritmen zijn het onderwerp van vele wetenschappelijke artikelen geweest. Meestal wordt maar één sensortype beschouwd en met de magnetische verzadiging wordt niet vaak rekening gehouden. Een nieuwe combinatie van een schatter met gesloten terugkoppeling en een FDI-techniek gebaseerd op het ‘cumulative-sum' principe is voorgesteld. Zo kan het elektromagnetische koppel, de rotorstromen en positie worden geschat voor sensor FDI en fouttolerantie met beperkte rekenkosten en zonder de magnetische verzadering te verwaarlozen. Het algoritme wordt in stabiele toestand gevalideerd, maar ook in het geval van gematigde transiënte situaties, onevenwichtige netwerkomstandigheden en een verkeerde schatting van DFIG parameters. Het kan ook vanzelf starten tijdens de startprocedure van de generator.In de vervoersector beginnen hybride en elektrische voertuigen op de wegen te rijden. Maar vooreen intensiever gebruik van zo'n wagens zijn er nog technologische verbeteringen nodig met betrekking tot autonomie, prestaties en ook geluid en trillingen (NVH). Het tweede deel van de thesis betreft die laatste uitdaging en bestaat uit het experimentele onderzoek van geluid en trillingen op een 8/6 variabelereluctantiemachine (SRM) ontwikkeld voor elektrische voertuigen.De NVH-problemen van SRM's beperken hun gebruik in automobiele en andere toepassingen enonderzoek wordt erover voortgezet. Vele wetenschappelijke artikelen focussen toch op modale analyse of gedetailleerde fenomenen terwijl een globale evaluatie van NVH aspecten in SRM's in gewone operatiecondities nauwelijks wordt gemaakt. Hetzelfde geldt voor het gebruik van reproduceerbare geluidsmetrieken. Een globale en vrij vlugge experimentele methode is hier voorgesteld om het NVH gedrag te schatten. Testen worden in transiënte situaties uitgevoerd om een brede frequentieband te exciteren, indien mogelijk met voortdurend variërende condities. De gemeten fasestroom, trilling en geluid worden als kleurmappen geplot om het verschil tussen beïnvloede en niet geaffecteerde frequenties te vergemakkelijken en met de berekende akoestische luidheid en scherpte vergeleken.Bovendien heeft de implementatie van een sneller bemonsterd stroomhysteresisregelaar geleid tot een verbetering van de regulatie- en akoestische kwaliteit door de amplitude van de stroomrimpeling en de excitatie van resonantiefrequenties te verminderen. De testresultaten tonen dat de schakelfrequentie voldoende hoog moet zijn om de excitatie van de ovale vervormingsmode te vermijden, maar niet te hoog om de scherpte van het geluid te beperken. De amplitude van de rimpel beïnvloedt ook de luidheid en daarvoor moet in aanmerking worden genomen. Bijgevolg zou ‘soft chopping'mode, of een lagere spanning op de DC-bus bij lage toerentallen, met een relatief klein hysteresisband beter worden gebruikt. Uiteindelijk wordt het geval van een openfasefout bestudeerd en onthult versterkte gelijke frequentievolgorden in de trilling- en geluidplots. / Doctorat en Sciences de l'ingénieur et technologie / info:eu-repo/semantics/nonPublished

Cette thèse de doctorat s'inscrit dans un projet pour le développement du véhicule électrique piloté par la société Renault. Il répond aux prévisions d’exploitation de véhicules électriques pour des déplacements interurbains et urbains afin d’améliorer les aspects environnementaux. L'objectif de nos travaux a été de développer un outil capable de prédire le bruit d'origine électromagnétique produit par des machines à rotor passifs : machine à réluctance variable, sur une large plage de vitesse. Pour cela, le développement d’un modèle vibro-acoustique reposant sur les équations aux dérivées partielles permet d’obtenir une bonne estimation des vibrations et du bruit de la machine pour une force donnée. Cette modélisation analytique couplée à un outil éléments finis, permettant ainsi d’estimer précisément les pressions radiales d’origine magnétique, fournit sous forme de sonagramme le bruit de la machine sur une large plage de vitesse. Cette approche dite hybride « numérique et analytique » offre l’avantage d’un très bon compromis temps de calcul – précision afin de concevoir des machines peu bruyantes. Enfin une analyse des effets de la saturation de ces machines ainsi qu’une analyse harmonique par produit de convolution sont fournis. / This thesis is related to the development of an electric car by Renault. This vehicle respects the constraints in order to improve environmental aspects. The aim of this work is to develop a tool capable of predicting electromagnetic noise generated by motors with passive rotor: switched reluctance machine, for a large range of speed.For that, a vibro-acoustic model based on an analytical approach was developed. It gives a good estimation of the vibrations and noise of the machine for a given force. This analytical model is coupled with Finite Element models which allows accurate estimation of radial Maxwell pressure and gives the sonogram of the radiated noise regarding a large range of speed.The advantage of this “hybrid” approach (Finite Element and analytical) is the very good compromise accuracy/computational time in order to design less noisy motors. Finally, an analysis of the saturation effect and harmonic analysis using convolution were performed.

Abstract<p><p>1.\ / Doctorat en Sciences de l'ingénieur / info:eu-repo/semantics/nonPublished

La machine à réluctance variable peut être utilisée dans les véhicules électriques où pour des considérations d’autonomie, le rendement est crucial. En raison du fort champ de fuite dans la région de l’entrefer de la machine à réluctance variable due à sa géométrie particulière à pôles saillants, les pertes « cuivre » peuvent devenir conséquentes. Il est alors recommandé de ne pas placer les conducteurs au voisinage de l’entrefer. Cependant, des instructions concrètes pour la conception d’un enroulement optimal sont manquantes. Généralement, les pertes « cuivre » dans les machines électriques sont la somme des pertes Ohm DC classiques et des pertes additionnelles dites par courants de Foucault. Les pertes DC étant constantes à un point de fonctionnement donné, l’optimisation est axée alors sur la réduction des pertes par courants de Foucault en jouant sur la configuration géométrique de l’enroulement. Dans le cas de calculs répétitifs fastidieux, rencontrés par exemple lors des processus de conception et d’optimisation du bobinage des machines électriques, il y a un intérêt significatif à réduire le temps de calcul. Dans ce travail, on présente trois techniques de réduction du modèle et leurs applications dans les analyses par la méthode des éléments finis. Outre l’influence de la fréquence d’alimentation et de la section du conducteur, plusieurs facteurs liés à la configuration de l’enroulement influent sur les pertes additionnelles par courants de Foucault :i) la position du conducteur dans l’encoche au voisinage de la dent du stator ou de la zone de l’entrefer .ii) la disposition des conducteurs envers les lignes du champ magnétique bidimensionnelles de l’encoche .iii) l’utilisation d’un conducteur massif ou multi filamentaire; les filaments sont connectés en parallèle et peuvent permuter leurs positions périodiquement au sein du conducteur tout au long du bobinage. Dans cette thèse, on étudie principalement l’influence de la disposition géométrique des spires dans l’encoche et du type du conducteur utilisé s’il s’agit d’un conducteur massif, en fils de Litz ou en fils torsadés. Les pertes par courants de Foucault sont la conséquence d’un couplage fort électrique-magnétique entre la densité du courant et la variation en fonction du temps du champ magnétique. En utilisant le modèle de Maxwell, ce couplage est décrit par une équation différentielle à dérivée partielle qui ne peut être résolue simplement. La résolution de cette équation utilisant l’approche analytique n’est possible que sous certaines hypothèses simplificatrices qui peuvent dégrader la fiabilité de la solution. La modélisation par la méthode des éléments finis permet quant à elle de prendre en compte le mouvement du rotor et la non-linéarité du circuit magnétique garantissant ainsi une meilleure précision. Néanmoins, cela conduit à une large capacité de stockage et à un temps de calcul substantiel qui peut entraver tout processus de conception ou d’optimisation. Pour surmonter ce problème, on propose dans ce manuscrit trois techniques de réduction du modèle. Ces techniques assurent une réduction efficace de la taille du système matriciel associé à la modélisation par la méthode des éléments finis et diminuent par conséquent le temps de calcul : i) une réduction spatiale qui évite une modélisation en 3D des conducteurs complexes en fils torsadés et en fils de Litz et propose une modélisation 2D satisfaisante .ii) la technique de la perturbation. iii) la réduction de l’ordre du modèle utilisant la méthode de la décomposition orthogonale aux valeurs propres combinée à la méthode d’interpolation empirique discrète. La comparaison du modèle réduit à un modèle complet de référence montre l’efficacité de la réduction du modèle à réduire le temps de calcul tout en restant en deçà d’une erreur de précision acceptable. / The switched reluctance machine can be used in hybrid or electric vehicle where, for autonomy considerations, energy efficiency is crucial. Because of the strong stray field in the air-gap region of the switched reluctance machine due to its salient pole geometry, the copper losses can become substantial. It is firmly recommended therefore not to place the coil conductors near the air-gap region. Nevertheless, concrete instructions for optimal winding design are missing. The copper losses in electrical machines are subdivided into classical DC ohmic losses and additional eddy current losses occurring due to the time varying magnetic fields penetrating the copper conductors. Based on the fact that the DC losses are constant at a given operating point, the optimization is focused on reducing the eddy current losses by modifying the winding geometry configuration. In the case of tedious repetitive calculations, met for example during design and optimization processes of electrical machine windings, there is a significant interest in reducing the computation time. This work suggests three model reduction techniques and their applications in the finite element analyses.Besides the frequency of the excitation current and the cross section of the coil conductors, several factors related to the winding configuration can affect the addition al eddy current losses:i) the coil conductor position in the winding slot especially near the stator pole or close to the air gapii) the disposition of the coil conductor against the two-dimensional flux lines in the slot windingiii) the subdivision of the solid conductor into multiple parallel strands swapping their positions periodically in the conductor cross section throughout the length of the machine winding.This thesis mainly studies the influence of the geometric coils disposition in the slot windings and the type of the conductor used whether it is solid or stranded, with Litz or twisted wires.The eddy current losses exit through the strong electro-magnetic coupling between the electric current density and the time dependent magnetic flux lines penetrating the conductors; it is described mathematically by a partial differential equation that cannot be solved easily. The analytical approach, which is used practically for a quick resolution of the strong electro-magnetic coupling equation, is only possible under certain simplifying assumptions that deteriorate brutally the reliability of the copper losses calculation. The finite element modeling as for it, allows taking into account the rotor motion and the non-linear behavior of the magnetic circuit, thus ensuring a higher accuracy. However, it leads under these conditions to a substantial calculation time and requires large storage capacity. These constraints are critical and may hinder therefore any process of conception or optimization. In this thesis, we suggest three different model reduction techniques that can be effective in reducing the size of large scale complete finite element models and enable therefore to shorten the computational time:i) the spatial reduction avoiding the 3D modeling which seems required in the case of twisted and Litz wires and suggesting an alternative satisfactory 2D modeling.ii) the perturbation technique.iii) the model order reduction using the proper orthogonal decomposition combined with the discrete empirical interpolation method.The comparison between the reduced model solutions to that of the complete finite element model has proved the effectiveness of the proposed model reduction techniques; they allow shrinking the required computational time while staying below an acceptable error of accuracy.