O presente trabalho objetiva o estudo, obtenção e caracterização da liga magnética macia Fe-Si-P produzida por metalurgia do pó convencional visando à futura aplicação em núcleos de máquinas elétricas, atualmente fabricados por estampagem de chapas. Escolheu-se com base em testes prévios a liga Fe-3%Si-0,75%P. Para a obtenção da liga, foi utilizada a rota de mecâno-síntese com diferentes tempos de moagem: 1 h, 3 h e 9 h, além do material sem moagem para comparação. Na sequência compactaram-se uniaxialmente a frio os corpos de prova a 600 MPa seguido de sinterização a 1150 ºC em atmosfera de gás argônio. A análise da influência do tempo de moagem nas propriedades físicas, mecânicas, magnéticas e elétricas no material sinterizado foi a meta central deste trabalho. A caracterização das propriedades físicas mostrou uma redução da densidade aparente do pó moído, um aumento da distribuição do tamanho de partícula e redução do mesmo com o aumento do tempo de moagem. No que se refere às propriedades magnéticas, evidenciou-se que o material moído durante 3h apresentou os melhores resultados de indução de saturação (1,15 T), apesar do aumento na coercitividade já previsto devido ao processo de mecâno-síntese. Além disso, a difração de raios-X detectou a formação da liga através da solução sólida dos elementos P e Si na matriz ferrita. A análise metalográfica revelou a diminuição do tamanho de grãos com o aumento do tempo de moagem. Por fim, realizou-se a simulação do protótipo para análise do desempenho do material visando à aplicação futura. Esta, realizada pelo método de elementos finitos em um núcleo de um gerador síncrono com ímãs permanentes de NdFeB resultou em uma densidade de fluxo (1,95T) para o material com 3h de moagem e um torque de apenas 13% inferior se comparado ao gerador convencional produzido com núcleos de chapas de aço elétrico. / The present work aims to study, obtaining and characterization of Fe-Si-P soft magnetic alloy produced by conventional powder metallurgy intended for the future application in electrical machines cores, currently manufactured by sheet metal forming. The alloy Fe-3%Si-0,75%P was chosen based on previous tests. To obtain the alloy was used mechanical alloying route with different milling times: 1 h, 3 h and 9 h, and the material without milling for comparison. In the sequence, the specimens were uniaxially cold compacted at 600 MPa followed by sintering at 1150 ° C in an atmosphere of argon. The analysis of the influence of milling time on the physical, mechanical, magnetic and electric properties of the sintered material was the central goal of this work. The physical properties characterization showed a reduction in the bulk apparent density of the milled powder, an increase in particle size distribution and reduction thereof with increasing milling time. As regards magnetic properties, it was observed that the milled material for 3 hours showed the best results of saturation induction (1.15 T), despite the increase in the coercivity as expected due to the inherent mechanical alloying process. Furthermore, the X-ray diffraction detected the alloy formation through the solid solution of P and Si elements in the ferrite matrix. The metallographic analysis showed the decrease in grain size with increasing milling time. Finally, were performed a simulation prototype for analysis of material performance in order to future implement. This, held by finite element method on a synchronous generator core with NdFeB permanent magnets, resulting in a flux density (1.95 T) for the material with 3h of milling and a torque of only 13% lower compared to conventional generator produced with cores of electric steel sheet.

O presente trabalho trata do estudo, análise, construção e teste de uma nova configuração para um atuador planar. O dispositivo é composto de um núcleo de armadura ferromagnético plano, estático e sem ranhuras sobre o qual são montados dois conjuntos de enrolamentos planares, ortogonais entre si, com quatro bobinas cada, eletricamente independentes entre si. A parte móvel consiste de um carro equipado com ímãs permanentes de alto produto energético responsáveis pela produção de fluxo magnético de excitação. A movimentação bidirecional sobre o plano se dá pela interação entre esse fluxo e a corrente elétrica adequadamente aplicada aos enrolamentos. O atuador apresenta uma distribuição espacial da densidade de fluxo magnético em toda a sua estrutura. Este trabalho preocupa-se em analisar numérica e experimentalmente os fenômenos eletromagnéticos envolvidos, tanto em regime estático como dinâmico. O emprego de dois diferentes materiais utilizados separadamente no núcleo da armadura é investigado: o aço maciço (caso 1) e um compósito magneticamente macio de grão isolado (caso 2). Devido à movimentação do carro e conseqüentemente do fluxo magnético de excitação, uma força eletromotriz induzida aparecerá no núcleo da armadura, sendo responsável pelo estabelecimento de correntes elétricas induzidas no mesmo. Essas correntes, que também dependem da condutividade do material do núcleo, produzem um efeito de frenagem sobre o carro do atuador que afeta a sua dinâmica. Produzem ainda perdas Joule no núcleo da armadura. A redução desses efeitos pode ser obtida com a utilização de um material magnético isotrópico de alta resistividade, caso 2, que possibilita ainda a distribuição tridimensional da densidade de fluxo magnético na estrutura do atuador. Uma análise dinâmica a partir do método dos elementos finitos tornou possível a verificação da distribuição da densidade de corrente elétrica induzida no núcleo da armadura, bem como a obtenção dos seus valores em função da velocidade do carro e do material utilizado. Ainda, o efeito de frenagem foi quantificado em ensaios práticos, propondo-se então um coeficiente de atrito total, k, para cada um dos dois casos em estudo. Nessa caracterização, obteve-se que o coeficiente de atrito eletromagnético, devido às correntes induzidas, de 1,74469 Ns/m para o caso 1, enquanto que para o caso 2 esse valor fica em 0,261285 Ns/m. Os resultados numéricos e experimentais apontam que existem diferenças significativas na utilização dos dois materiais propostos, indicando que o caso 2, quando utilizado de maneira adequada no sistema, reduz as correntes elétricas induzidas minimizando seus efeitos. / The present work deals with the study, analysis, construction and testing of a new configuration of a planar actuator. The device comprehends a static ferromagnetic slotless core in form of slab, on which two sets of planar windings are assembled. They are orthogonal with respect to each other and have four independent coils. The moving part consists of a car, equipped with high energy product permanent magnets that deliver the excitation magnetic flux. The bidirectional movement on the plan is a result of the interaction between the excitation magnetic flux and the electric currents that fed the armature windings properly. The actuator features a spatial distribution of the magnetic flux density throughout its structure. This work is concerned with the numerical and experimental analyses of the electromagnetic effects involved in terms of static and dynamic behavior of the actuator. These effects are investigated for two different materials employed separately in the core of the armature: solid steel (case 1) and a grain isolated soft magnetic composite (case 2). Owing to the movement of the car and so the excitation magnetic flux, an induced electromotive force appears on the core of the armature and is responsible for the establishment of induced electrical currents in there. These currents, that also depend on the conductivity of the material of the armature core, produce a braking effect on the car that affects the dynamics of the actuator. It also produces Joule losses on that core. The reduction of those effects can be obtained with the use of an isotropic ferromagnetic material with high resistivity, case 2, that allows the 3d distribution of magnetic flux density on the structure of the actuator. A dynamic analysis by means of the finite element method made possible to verify the distribution of the induced electrical current density in the core of the armature, and to compute its value according to the speed of the car and to the material employed. Still, the effect of the braking force was quantified experimentally; as a result, a total friction coefficient, k, is proposed in order to take into account that force. By doing that, a resulting coefficient of electromagnetic friction due to the induced currents is 1.74469 Ns/m for case 1, while for case 2 it is 0.261285 Ns/m. The numerical and experimental results indicate that exist significant differences in the use of the two materials proposed, indicating that the case 2, when used in an appropriate manner, reduces the induced electrical currents minimizing its effects.

O presente trabalho objetiva o estudo, obtenção e caracterização da liga magnética macia Fe-Si-P produzida por metalurgia do pó convencional visando à futura aplicação em núcleos de máquinas elétricas, atualmente fabricados por estampagem de chapas. Escolheu-se com base em testes prévios a liga Fe-3%Si-0,75%P. Para a obtenção da liga, foi utilizada a rota de mecâno-síntese com diferentes tempos de moagem: 1 h, 3 h e 9 h, além do material sem moagem para comparação. Na sequência compactaram-se uniaxialmente a frio os corpos de prova a 600 MPa seguido de sinterização a 1150 ºC em atmosfera de gás argônio. A análise da influência do tempo de moagem nas propriedades físicas, mecânicas, magnéticas e elétricas no material sinterizado foi a meta central deste trabalho. A caracterização das propriedades físicas mostrou uma redução da densidade aparente do pó moído, um aumento da distribuição do tamanho de partícula e redução do mesmo com o aumento do tempo de moagem. No que se refere às propriedades magnéticas, evidenciou-se que o material moído durante 3h apresentou os melhores resultados de indução de saturação (1,15 T), apesar do aumento na coercitividade já previsto devido ao processo de mecâno-síntese. Além disso, a difração de raios-X detectou a formação da liga através da solução sólida dos elementos P e Si na matriz ferrita. A análise metalográfica revelou a diminuição do tamanho de grãos com o aumento do tempo de moagem. Por fim, realizou-se a simulação do protótipo para análise do desempenho do material visando à aplicação futura. Esta, realizada pelo método de elementos finitos em um núcleo de um gerador síncrono com ímãs permanentes de NdFeB resultou em uma densidade de fluxo (1,95T) para o material com 3h de moagem e um torque de apenas 13% inferior se comparado ao gerador convencional produzido com núcleos de chapas de aço elétrico. / The present work aims to study, obtaining and characterization of Fe-Si-P soft magnetic alloy produced by conventional powder metallurgy intended for the future application in electrical machines cores, currently manufactured by sheet metal forming. The alloy Fe-3%Si-0,75%P was chosen based on previous tests. To obtain the alloy was used mechanical alloying route with different milling times: 1 h, 3 h and 9 h, and the material without milling for comparison. In the sequence, the specimens were uniaxially cold compacted at 600 MPa followed by sintering at 1150 ° C in an atmosphere of argon. The analysis of the influence of milling time on the physical, mechanical, magnetic and electric properties of the sintered material was the central goal of this work. The physical properties characterization showed a reduction in the bulk apparent density of the milled powder, an increase in particle size distribution and reduction thereof with increasing milling time. As regards magnetic properties, it was observed that the milled material for 3 hours showed the best results of saturation induction (1.15 T), despite the increase in the coercivity as expected due to the inherent mechanical alloying process. Furthermore, the X-ray diffraction detected the alloy formation through the solid solution of P and Si elements in the ferrite matrix. The metallographic analysis showed the decrease in grain size with increasing milling time. Finally, were performed a simulation prototype for analysis of material performance in order to future implement. This, held by finite element method on a synchronous generator core with NdFeB permanent magnets, resulting in a flux density (1.95 T) for the material with 3h of milling and a torque of only 13% lower compared to conventional generator produced with cores of electric steel sheet.

O presente trabalho trata do estudo, análise, construção e teste de uma nova configuração para um atuador planar. O dispositivo é composto de um núcleo de armadura ferromagnético plano, estático e sem ranhuras sobre o qual são montados dois conjuntos de enrolamentos planares, ortogonais entre si, com quatro bobinas cada, eletricamente independentes entre si. A parte móvel consiste de um carro equipado com ímãs permanentes de alto produto energético responsáveis pela produção de fluxo magnético de excitação. A movimentação bidirecional sobre o plano se dá pela interação entre esse fluxo e a corrente elétrica adequadamente aplicada aos enrolamentos. O atuador apresenta uma distribuição espacial da densidade de fluxo magnético em toda a sua estrutura. Este trabalho preocupa-se em analisar numérica e experimentalmente os fenômenos eletromagnéticos envolvidos, tanto em regime estático como dinâmico. O emprego de dois diferentes materiais utilizados separadamente no núcleo da armadura é investigado: o aço maciço (caso 1) e um compósito magneticamente macio de grão isolado (caso 2). Devido à movimentação do carro e conseqüentemente do fluxo magnético de excitação, uma força eletromotriz induzida aparecerá no núcleo da armadura, sendo responsável pelo estabelecimento de correntes elétricas induzidas no mesmo. Essas correntes, que também dependem da condutividade do material do núcleo, produzem um efeito de frenagem sobre o carro do atuador que afeta a sua dinâmica. Produzem ainda perdas Joule no núcleo da armadura. A redução desses efeitos pode ser obtida com a utilização de um material magnético isotrópico de alta resistividade, caso 2, que possibilita ainda a distribuição tridimensional da densidade de fluxo magnético na estrutura do atuador. Uma análise dinâmica a partir do método dos elementos finitos tornou possível a verificação da distribuição da densidade de corrente elétrica induzida no núcleo da armadura, bem como a obtenção dos seus valores em função da velocidade do carro e do material utilizado. Ainda, o efeito de frenagem foi quantificado em ensaios práticos, propondo-se então um coeficiente de atrito total, k, para cada um dos dois casos em estudo. Nessa caracterização, obteve-se que o coeficiente de atrito eletromagnético, devido às correntes induzidas, de 1,74469 Ns/m para o caso 1, enquanto que para o caso 2 esse valor fica em 0,261285 Ns/m. Os resultados numéricos e experimentais apontam que existem diferenças significativas na utilização dos dois materiais propostos, indicando que o caso 2, quando utilizado de maneira adequada no sistema, reduz as correntes elétricas induzidas minimizando seus efeitos. / The present work deals with the study, analysis, construction and testing of a new configuration of a planar actuator. The device comprehends a static ferromagnetic slotless core in form of slab, on which two sets of planar windings are assembled. They are orthogonal with respect to each other and have four independent coils. The moving part consists of a car, equipped with high energy product permanent magnets that deliver the excitation magnetic flux. The bidirectional movement on the plan is a result of the interaction between the excitation magnetic flux and the electric currents that fed the armature windings properly. The actuator features a spatial distribution of the magnetic flux density throughout its structure. This work is concerned with the numerical and experimental analyses of the electromagnetic effects involved in terms of static and dynamic behavior of the actuator. These effects are investigated for two different materials employed separately in the core of the armature: solid steel (case 1) and a grain isolated soft magnetic composite (case 2). Owing to the movement of the car and so the excitation magnetic flux, an induced electromotive force appears on the core of the armature and is responsible for the establishment of induced electrical currents in there. These currents, that also depend on the conductivity of the material of the armature core, produce a braking effect on the car that affects the dynamics of the actuator. It also produces Joule losses on that core. The reduction of those effects can be obtained with the use of an isotropic ferromagnetic material with high resistivity, case 2, that allows the 3d distribution of magnetic flux density on the structure of the actuator. A dynamic analysis by means of the finite element method made possible to verify the distribution of the induced electrical current density in the core of the armature, and to compute its value according to the speed of the car and to the material employed. Still, the effect of the braking force was quantified experimentally; as a result, a total friction coefficient, k, is proposed in order to take into account that force. By doing that, a resulting coefficient of electromagnetic friction due to the induced currents is 1.74469 Ns/m for case 1, while for case 2 it is 0.261285 Ns/m. The numerical and experimental results indicate that exist significant differences in the use of the two materials proposed, indicating that the case 2, when used in an appropriate manner, reduces the induced electrical currents minimizing its effects.

La construction électrique reposant en grande partie sur l’utilisation des propriétés électromagnétiques du fer et de ses alliages, les concepteurs ont besoin d’une connaissance précise de ces propriétés. Les caractéristiques des matériaux magnétiques doux, typiquement celles de l’acier des roues polaires d'une machine à griffes, peuvent être notablement impactées par les procédés de fabrication. Celles-ci doivent alors être caractérisées directement sur la pièce finale. Dans ce travail, on propose une méthode de mesure non destructive combinant une démarche opératoire et la simulation par éléments finis afin de caractériser la conductivité électrique locale des roues polaires. Afin d’adapter les paramètres expérimentaux à la géométrie de la pièce considérée, et à l’aide d’un diagramme 5M (ou diagramme d'Ishikawa), une démarche d’optimisation de la méthode est entreprise. Puis l’incertitude de mesure est déterminée à l’aide de deux démarches différentes. Cette méthode est ensuite exploitée pour mener une étude sur une population de roues polaires extraites de la chaîne de production. Dans un second temps, la méthode est étendue pour la mesure de perméabilité incrémentale. Des essais sur tôles épaisses ont permis de valider l’approche proposée à l'aide du même type de capteur. Par ailleurs, une étude complémentaire par éléments finis 3D a permis de mettre en évidence les limites de l'approche analytique, notamment lorsque la perméabilité de la plaque et son épaisseur deviennent trop importantes. Finalement, cette méthode est appliquée au cas des roues polaire, dans le cadre d’une approche qualitative, en vue d’une application de type contrôle qualité. / Electrical energy conversion devices are based on the use of electromagnetic properties of iron and its alloys. Therefore, an accurate knowledge of these properties is required for the designers. The characteristics of the soft magnetic materials, typically those of a claw pole rotor, can be significantly impacted by the manufacturing processes. Consequently, these properties must be characterized directly on the manufactured magnetic piece. In this work, a non-destructive measurement method combining an operative approach and the finite element simulation is proposed to characterize the local electrical conductivity of the claw pole rotor. The choice of the experimental parameters associated to the claw pole rotor geometry is optimized using the Ishikawa diagram. Then, the measurement uncertainty is determined using two different approaches. This method is applied to perform a study on a population of claw pole rotors issued from the manufacturing chain. Secondly, the method is extended to incremental permeability measurement. Tests on thick sheets were realized to validate the proposed approach with the same type of sensor. Moreover, a complementary study in 3D finite element has emphasized the limitations of the analytical approach, especially when the permeability of the plate and its thickness become significant. Finally, this method is applied to the case of claw pole rotors through a qualitative approach for a quality control application.

L'alternateur à griffes est l'alternateur le plus utilisé dans l'industrie automobile. Afin d'augmenter sa puissance volumique, une solution classique consiste à utiliser des aimants NdFeB entre les griffes. Ces dernières années, le prix des aimants NdFeB a beaucoup augmenté remettant en question leur utilisation. Ce contexte implique de trouver de nouvelles solutions techniques permettant de conserver la même puissance volumique sans utiliser d'aimant NdFeB. Dans le cadre de ces travaux de thèse la solution proposée consiste a utiliser des matériaux magnétiques doux nobles tels que les FeCo (AFK18, AFK1 et AFK502). De part leur coût élevé, nous avons limité leur utilisation au noyau de l'alternateur même si leur utilisation au rotor est également évaluée. Ces travaux s'appuient sur une démarche de dimensionnement multi-niveaux (modèle reluctant et modèle éléments finis) ce qui apporte un bon compromis temps de calcul/précision. Une série d'études a été réalisée avec dans un premier temps, l'identification d'une géométrie de noyau favorable à l'utilisation de noyau en FeCo. Dans un second temps, une étude compare les courants batteries en fonction du FeCo utilisé au noyau avec une optimisation du rotor. Ensuite une étude présente le dimensionnement complet de l'alternateur (optimisation du rotor et du stator avec une étude sur le nombre optimal de paires de pôles) avec un noyau en AFK502 ce qui d'identifier le gain maximal en courant batterie apporté par l'utilisation d'un noyau en FeCo. Pour finir, une dernière étude compare les courants batteries en fonction du FeCo utilisé au rotor avec une optimisation du rotor et du stator. / Claw-pole alternators are often used in automotive industry. Permanent magnets like NdFEB are currently integrated to increased the power density of claw-pole machine. However their higher price brings into question their usage. This tight context implies finding new technical solutions to keep the same power density without NdFeB magnets. The solution adopted consists to evaluate the potential of gain with different soft magnetic materials and more especially FeCo family (AFK18, AFK1 et AFK502). Their higher price imposed us to use FeCo just at the core of the alternator but we have also evaluate their usage at the rotor. This work is based on an adapted design methodology including two modeling level (magnetic equivalent circuit model and finite element model) in order to obtain a good compromise between time computation/accuracy. Several studies have been made with, as a first step, the identification of new core geometry customized for FeCo core. As a second step, a study comparing output current according to FeCo used at the core is presented, rotor is optimized only. As a third step, is exposed the global optimization of the alternator with an AFK502 (rotor and stator optimization with a study on the optimal poles pairs number) in order to identify the maximum output current gain with an FeCo core. Finally, the last study compare output current according to FeCo used at the rotor, rotor and stator are optimized .

No description available.

Magnetic components are necessary for switch-mode power electronics converters, but they are often the bulkiest and heaviest in the system. Novel magnetic designs with intricate structures lead to the size reduction of power electronics converters but pose challenges to the fabrication process and material availability. Because of their low-temperature and pressure-less process-ability, magnetic pastes would be the material of choice to make magnetic cores with complex geometries. However, most magnetic pastes reported in the literature suffer from low relative permeability (µr < 26) due to the low magnetic fraction limited by viscosity. The conventional approach of developing magnetic pastes involves experimental iterations with trial-and-error efforts to determine the optimal compositions. To shorten the development cycle and take advantage of the computational power in the current age, this work focuses on exploring, validating, and demonstrating a computer-aided methodology to correlate material's processing, microstructure, and property to guide the development of magnetic pastes. The discrete element method (DEM) simulation was explored to create materials' microstructure and the finite element method (FEM) simulation was utilized to study the magnetic permeability based on the microstructure created by DEM or taken from an actual material sample. The combination of DEM and FEM provided the linkage among processing-microstructure-property relations. Then, the methodology was verified and demonstrated by improving a starting formulation. The formulation was modeled with DEM based on multiple variables, e.g., particle shape, size, size distribution, mixing ratio, gap, gap distribution, magnetic volume fraction, etc. The optimal mixing ratio of different powders to achieve the maximum magnetic fraction was determined by DEM. Experimental results confirmed the predicted optimal mixing ratio. To further take advantage of the computational tools, the magnetic permeability of the magnetic pastes was computed by FEM based on the DEM-generated microstructures. The effects of powder mixing ratio and magnetic volume fraction on the magnetic permeability were studied, respectively. Compared with the experimental values, the microstructure-based FEM simulations could predict the magnetic permeability of the formulations with varied powder mixing ratios or magnetic volume fractions with an average error of only 10 %. Another critical aspect of employing magnetic pastes for magnetic components in power electronics is capable of tailoring their magnetic permeability to meet different design needs. The methodology was further verified and demonstrated by guiding the selection of composition parameters for tailorable magnetic permeability of a starting formulation with flaky particles. An FEM model was constructed from a microstructural image and varied parameters were explored (particle permeability, matrix permeability, particle volume fraction, etc.) to tailor the magnetic permeability. To verify the simulated results, a set of magnetic pastes with various volume fractions of flakes was prepared experimentally and characterized for their permeability. Comparing the simulated and measured permeability, the error was found to be less than 10 %. Last, the guideline was demonstrated to predict a material composition to achieve a target relative permeability of 30. From the predicted composition, the magnetic paste was prepared and characterized. The error between experimental permeability and the target was only 5 %. With the guideline, one can formulate magnetic pastes with tailorable permeability with minimal experimental effort and select the composition parameters to achieve a target permeability. After developing a series of magnetic pastes with tailorable permeability and a maximum value of 35, the feasibility of making magnetic components with magnetic pastes was demonstrated. The commonly used magnetic cores – C-core, E-core, toroid core, bar core, and plate core were fabricated by a low-temperature (< 200 °C) and pressure-less molding process. Several innovative magnetic components with intricate core structures were also fabricated to demonstrate the shape-forming flexibility. The magnetic paste can also be used as the feedstock for paste-extrusion-based additive manufacturing, which further enhances the shape-forming capability. For demonstration, a multi-permeability core was fabricated by 3D printing the magnetic pastes with tailored permeability. The feasibility of making high-performance magnetic components by additive manufacturing or low-temperature pressure-less molding of magnetic pastes opens the door to power electronics researchers to explore more innovative magnetic designs to further improve the efficiency and power density of the power electronics converters. / Doctor of Philosophy / Magnetic components are necessary for switch-mode power electronics converters, but they are often the bulkiest and heaviest in the system. To reduce the size of the power converters, it is crucial to reduce the size of magnetic components by employing innovative magnetic designs. However, the complicated geometries of the novel magnetic designs pose challenges to the availability of material feedstock and the fabrication process. Magnetic pastes would be the material of choice to make magnetic components with intricate structures because of their flexibility in shape-forming with low-temperature and pressure-less processes. However, most magnetic pastes reported in the literature suffer from low magnetic permeability due to the low magnetic fraction limited by viscosity. The conventional approach of developing magnetic pastes involves experimental trial-and-error efforts to determine the optimal compositions. To shorten the development cycle and take advantage of computational power in the current age, this project focuses on exploring, validating, and demonstrating a computer-aided way to correlate material's processing, microstructure, and property relations to guide material development. The numerical simulations were explored to generate the microstructures and study the properties. With the guidance provided by computer simulations, a series of magnetic pastes with tailorable permeability was developed. Several novel magnetic components were fabricated with the as-developed magnetic pastes via molding or additive manufacturing to demonstrate the shape-forming flexibility.

La capacité à détecter des micro-défauts ou des défauts profonds dans les pièces métalliques constitue un enjeu important pour l'industrie de l'aéronautique ou du nucléaire. La technique de contrôle non destructif (CND) par courant de Foucault est souvent utilisée pour cette application. Cette thèse s’inscrit dans le cadre d'une collaboration ayant pour but la réalisation et l'intégration de micro-capteurs de champ magnétique basés sur l’effet de magnéto-impédance (MI) à des systèmes de détection par CND. Ces micro-capteurs de structure multicouche (ferromagnétique/conducteur/ferromagnétique) ont été élaborés en salle blanche par dépôt de films minces. Un traitement thermique sous champ magnétique a ensuite permis d’optimiser les propriétés du matériau et d’induire des anisotropies dans le plan des couches ferromagnétiques. Une méthode basée sur la double démodulation d’amplitude du signal de mesure a été proposée pour la caractérisation dynamique des capteurs. Les paramètres importants tel que la géométrie, l’anisotropie et la fréquence d’excitation ont été étudiés afin d’optimiser les caractéristiques. Les résultats ont montré la nécessité de polariser les capteurs en champ. Nous avons donc étudié la possibilité de réaliser, grâce à une technique de micromoulage épais, un microsolénoïde 3D et des travaux préliminaires sur l’intégration d'un capteur dans le microsolénoïde par transfert de film ont été effectués. Enfin, une étude théorique a été réalisée en tenant compte des résultats obtenus expérimentalement. Pour cela, le modèle de Landau-Lifshitz-Gilbert (LLG) a été implanté dans un code de calcul électromagnétique par éléments finis permettant de calculer l’impédance du capteur en fonction du champ magnétique appliqué. / The capability to detect micro-defects or buried flaws in the metallic parts is an important issue for the aerospace or nuclear industry. The technique of nondestructive testing (NDT) by eddy current is widely used for these applications. This thesis is part of collaboration project aimed at the realization and integration of magnetic field microsensors based on the magneto-impedance (MI) effect for the NDT detection systems. These multilayered structure microsensors (ferromagnetic/conductor/ferromagnetic) were realized in the clean room by thin film deposition method. A post-annealing step with magnetic field was then used to optimize the material properties and to induce magnetic anisotropy in the ferromagnetic layers. A method based on the double amplitude demodulation was proposed for the dynamic characterization of the sensors. The important parameters such as the geometry, the anisotropy and the driven frequency were studied in order to optimize the characteristics. The results showed that a bias field is necessary for the application. Therefore, we have investigated the possibility to realize, through thick micromoulding technique, a 3D microsolenoid and preliminary work on integrating a sensor in the microsolenoid by film transfer has been carried out. Finally, a theoretical study was investigated by taking into account the results obtained experimentally. For this purpose, the model of Landau-Lifshitz-Gilbert (LLG) has been implemented in an electromagnetic finite element calculation program in order to determine the impedance of the sensor as a function of the applied magnetic field.

O trabalho apresenta o desenvolvimento de uma metodologia denominada modelo de núcleo reduzido, aplicada para avaliar o desempenho de máquinas elétricas no que tange a geometria e materiais empregados na fabricação do núcleo completo. Para fins de validação da metodologia utiliza-se um Atuador Planar de Indução Trifásico com dois graus de liberdade, comparando os resultados numéricos e experimentais. Através desta metodologia, pode-se realizar a análise dos fenômenos eletromagnéticos ocorridos no núcleo completo por meio da avaliação de seu modelo reduzido, composto neste caso por 33% do núcleo completo empregado no Atuador Planar de Indução Trifásico. A comprovação da metodologia do modelo de núcleo reduzido ocorreu através da fabricação de uma bancada de testes, composta por uma célula de carga para realizar aquisição da força de propulsão planar, interface de potência e os núcleos reduzidos com seguintes materiais ferromagnéticos: compósitos SMC 1P Somaloy 500®, Ferro resinado e Aço ABNT 1020. Com auxilio da estrutura de testes, validou-se o modelo numérico dos três núcleos reduzidos quanto a força de propulsão planar. Na análise dos dados experimentais e numéricos, o material Ferro resinado apresentou a diferença 14% referente a força de propulsão planar, sendo a maior diferença entre os materiais estudados. Com a convergência dos resultados experimental e numéricos, realiza-se a comparação numérica entre os núcleos reduzidos e completos utilizando-se os três materiais ferromagnéticos. A análise numérica do núcleo reduzido com o material SMC 1P Somaloy 500® apresentou o fator de relação médio da força de propulsão planar de 2,65 em relação ao núcleo completo. O núcleo completo com Aço ABNT 1020 resultou no consumo médio de 56,7Watts para gerar a força de propulsão planar de 1 Newton. Dessa forma, proporciona-se uma ferramenta de maior rapidez para fabricação e avaliação do desempenho de materiais ferromagnéticos utilizados no núcleo completo da máquina elétrica. / This paper presents the development of a methodology denominated low core model applied to evaluate the performance of electrical machines with respect to geometry and materials used in manufacturing of the complete core. For validation purposes of the methodology is used a Planar Three-phase Induction Actuator with two degrees of freedom, comparing the experimental and numerical results. Through this methodology, it is possible to perform the analysis of electromagnetic phenomena occurring in the complete core based evaluation of the reduced model, made in this case with 33% of the full core employed in the Planar Three-phase Induction Actuator. The verification of the reduced core model methodology occurred through the manufacture of a testing bench, which is composed of a load cell to realize the acquisition of the planar propulsion force, potency interface and reduced cores with the following ferromagnetic materials: SMC 1P Somaloy 500® composites, resinated Iron and Steel ABNT 1020. With the help of the test structure, it was validated the numerical model of the three reduced cores regarding to the planar propulsion force. In the analysis of experimental and numerical data, the resinated Iron material showed a 14% difference concerning the strength of the planar propulsion, which is the biggest difference between the materials studied. With the convergence of the experimental and numerical results, a numerical comparison is performed between the reduced and complete cores using the three ferromagnetic materials. The numerical analysis of the reduced core with the SMC 1P Somaloy 500® material showed the average ratio of the planar factor propulsive force of 2.65 when compared with the complete core. The complete core with ABNT 1020 Steel resulted in an average consumption of 56.7 Watts to generate a planar propulsive force of 1 Newton. Thus, it is provided a faster tool for manufacturing and evaluation of ferromagnetic materials performance used in the complete core of the electric machine.