Temperature is one of the parameters that limits the output torque and reduces the lifespan of electrical machines. Models that can provide accurate estimation of the temperature field in the most critical components (e.g. windings) at lower computational effort can be useful to improve the design process and reduce the time to market. Depending on the application, engineers usually rely on hi-fidelity models, e.g. based on the finite elements method (FEM), or lower order models, e.g. thermal equivalent circuits (TECs). The aim of the present work is to provide new tools and methodologies to obtain the temperature distribution within the windings using reduced order hi-fidelity models or improved TEC that could account for any working condition, including AC effects. A new methodology, based on the multiple scales method (MSM), is introduced which homogenises the complex windings domain and allows for the estimation of its effective thermal properties. The homogenisation through the MSM is performed solving a single elementary cell. The MSM also allows for the reconstruction of the actual thermal field. Extensive numerical and experimental validation is provided, in particular for the case of electrical windings encapsulated with epoxy. The thermal homogenisation is then combined with an electromagnetic homogenisation technique to estimate winding losses including AC effects, such as proximity and skin effects. The coupled analysis is validated numerically on reference test problems, and experimentally, on a suitably built "motorette". The method is proven to correctly predict losses including thermal effects and to estimate magnitude and location of the temperature hotspot within the winding domain. This work also introduces a new approach for building thermal equivalent circuits that represents the most commonly employed modelling technique for electrical machine thermal analysis. Here the TEC approaches are thoroughly analysed, highlighting limitations. The proposed new technique extends the range of numerical accuracy, accounting for high Biot numbers (up to Bi = 2) and internal heat generation. The result of this approach is higher spatial resolution about the temperature field within the winding domain and thus enables improved information on hotspot location and magnitude. The method is experimentally validated and also applied to model an electrical machine for full-electric in-wheel vehicle propulsion.

O objetivo principal do projeto foi desenvolver, através da metalurgia do pó (M/P), núcleos para transformadores monofásicos de baixa potência. O processo compreende o desenvolvimento de ligas metálicas utilizando pós de ferro, níquel e resina fenólica HRJ. Essas ligas foram misturadas, compactadas e sinterizadas ou curadas, conforme o tipo de liga. Após a confecção dos protótipos, foram feitos testes relacionados às características eletromagnéticas. A partir dos resultados obtidos puderam-se fazer comparações entre um transformador convencional, construído com um núcleo de chapas laminadas de Fe-Si com os núcleos maciços confeccionados utilizando-se a metalurgia do pó. Entre os transformadores construídos a partir da metalurgia do pó, também puderam ser observados os comportamentos com núcleos formados a partir de pó de ferro, liga de ferro e níquel, que foram sinterizados e ainda uma liga de ferro com 1% de resina fenólica HRJ que foi curada para obtenção do núcleo magnético. / The main goal this design was to develop, through process of powder Metallurgy, single-phase transformer cores for low Power. The process include the development alloys using powders of iron, nickel and phenolic resin HRJ. These alloys were mixed, compacted and sintered or cured, according to the type of alloy. After the prototype creation, tests were made related to the electromagnetic characteristics. When the results were ready comparisons were made between a conventional transformer, built with a Fe-Si rolled sheet core and bulky cores made using the powder metallurgy. Between transformers built from the powder metallurgy, could also be observed behaviors with cores formed from iron powder, iron and nickel alloy that was sintered and observed too an iron alloy with 1% phenolic resin HRJ was cured to obtain the magnetic core.

Les Stations de Transfert d’Energie par Pompage (STEP) sont des structures importantes pour stabiliser le réseau électrique.Les technologies à vitesse variable peuvent améliorer l'efficacité et la souplesse d’utilisation des STEPs. Les technologies actuelles telles que les machines alimentées en fréquence variable, ou les Machines Asynchrone à Double Alimentations (MADA) présentent des inconvénients. Dans ce travail, nous nous concentrons sur une structure non conventionnelle de machine à vitesse variable : la Machine à Induction à Double Alimentation sans Balais (BDFM). Les objectifs sont de mieux comprendre le fonctionnement de cette machine pour la dimensionner, l’optimiser et finalement la comparer aux structures existantes.Après un examen des techniques de dimensionnement et d'optimisation des machines classiques, des approches similaires sont étudiées pour les BDFM. Deux méthodes différentes pour des simulations éléments finis plus rapides de la BDFM sont présentées : une première, la plus rapide mais qui ne considère pas le phénomène de saturation et une seconde basée sur le principe des simulations magnétoharmoniques. Une analyse harmonique minutieuse combinée à une comparaison de cas en charges (couplage-croisés) entre des simulations FE et les résultats obtenus avec des schémas équivalents obtenus dans la littérature conduit à une modification du circuit équivalent de la BDFM. Une nouvelle méthode pour déterminer les paramètres de ce circuit grâce à des essais électriques est ensuite présentée. La détermination des paramètres à partir de la géométrie est également abordée pour aboutir à un modèle semi-analytique dérivable. Un tel modèle, couplé à un algorithme d'optimisation du 1er ordre pourrait être extrêmement puissant lors du dimensionnement d'une BDFM. Le potentiel d'une telle approche est montré dans ce travail grâce à l'optimisation d'une machine à induction. / Pumped-hydro storage plants (PSP) are important assets to stabilize electric grids.Variable speed technologies can improve the cycle efficiency and the power adjustability of PSPs. Current technologies such as fully-fed machines or Doubly-Fed Induction Machines (DFIM) have drawbacks. In this work, the focus will be on an unconventional design of variable speed machine: the Brushless Doubly-Fed Induction Machine (BDFM). The objectives are to better understand the working principles of this machine so as to size it, optimize it, and compare it to other types of variable speed machines.Following a review of sizing and optimization techniques for conventional machines, similar approaches are investigated for BDFMs. Two different methods for faster Finite-Element (FE) simulations of the BDFM are presented: a fast one without saturation considerations and another one based on the principle of magneto-harmonic simulations. A careful harmonic analysis combined with a comparison of cross-coupling tests between FE simulations and results of equivalent circuit found in the literature will lead to a modification of the BDFM equivalent circuit. A new method to determine the parameters of thisequivalent circuit from electrical tests is presented. The parameters determination from the geometry will also be considered for the elaboration of a derivable semi-analytical model. Such a model, paired with a 1st order optimization algorithm could be extremely powerful during the sizing of a BDFM. The potential of such an approach is shown in this work with the optimization of an Induction Machine.

O objetivo principal do projeto foi desenvolver, através da metalurgia do pó (M/P), núcleos para transformadores monofásicos de baixa potência. O processo compreende o desenvolvimento de ligas metálicas utilizando pós de ferro, níquel e resina fenólica HRJ. Essas ligas foram misturadas, compactadas e sinterizadas ou curadas, conforme o tipo de liga. Após a confecção dos protótipos, foram feitos testes relacionados às características eletromagnéticas. A partir dos resultados obtidos puderam-se fazer comparações entre um transformador convencional, construído com um núcleo de chapas laminadas de Fe-Si com os núcleos maciços confeccionados utilizando-se a metalurgia do pó. Entre os transformadores construídos a partir da metalurgia do pó, também puderam ser observados os comportamentos com núcleos formados a partir de pó de ferro, liga de ferro e níquel, que foram sinterizados e ainda uma liga de ferro com 1% de resina fenólica HRJ que foi curada para obtenção do núcleo magnético. / The main goal this design was to develop, through process of powder Metallurgy, single-phase transformer cores for low Power. The process include the development alloys using powders of iron, nickel and phenolic resin HRJ. These alloys were mixed, compacted and sintered or cured, according to the type of alloy. After the prototype creation, tests were made related to the electromagnetic characteristics. When the results were ready comparisons were made between a conventional transformer, built with a Fe-Si rolled sheet core and bulky cores made using the powder metallurgy. Between transformers built from the powder metallurgy, could also be observed behaviors with cores formed from iron powder, iron and nickel alloy that was sintered and observed too an iron alloy with 1% phenolic resin HRJ was cured to obtain the magnetic core.

O objetivo principal do projeto foi desenvolver, através da metalurgia do pó (M/P), núcleos para transformadores monofásicos de baixa potência. O processo compreende o desenvolvimento de ligas metálicas utilizando pós de ferro, níquel e resina fenólica HRJ. Essas ligas foram misturadas, compactadas e sinterizadas ou curadas, conforme o tipo de liga. Após a confecção dos protótipos, foram feitos testes relacionados às características eletromagnéticas. A partir dos resultados obtidos puderam-se fazer comparações entre um transformador convencional, construído com um núcleo de chapas laminadas de Fe-Si com os núcleos maciços confeccionados utilizando-se a metalurgia do pó. Entre os transformadores construídos a partir da metalurgia do pó, também puderam ser observados os comportamentos com núcleos formados a partir de pó de ferro, liga de ferro e níquel, que foram sinterizados e ainda uma liga de ferro com 1% de resina fenólica HRJ que foi curada para obtenção do núcleo magnético. / The main goal this design was to develop, through process of powder Metallurgy, single-phase transformer cores for low Power. The process include the development alloys using powders of iron, nickel and phenolic resin HRJ. These alloys were mixed, compacted and sintered or cured, according to the type of alloy. After the prototype creation, tests were made related to the electromagnetic characteristics. When the results were ready comparisons were made between a conventional transformer, built with a Fe-Si rolled sheet core and bulky cores made using the powder metallurgy. Between transformers built from the powder metallurgy, could also be observed behaviors with cores formed from iron powder, iron and nickel alloy that was sintered and observed too an iron alloy with 1% phenolic resin HRJ was cured to obtain the magnetic core.

Orientador: Ernesto Ruppert Filho / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e Computação / Made available in DSpace on 2018-08-11T20:28:16Z (GMT). No. of bitstreams: 1 LuqueCarcasi_DiodomiroBaldomero_M.pdf: 943595 bytes, checksum: c20084d6cea7e72315ca4292797e783f (MD5) Previous issue date: 2005 / Resumo: Este trabalho apresenta um estudo sobre o comportamento de motores de indução trifásico em regime permanente. Discute-se a validade da utilização do circuito elétrico equivalente do motor nas condições nominais e fora das condições nominais de operação. Ensaios em vazio e com rotor bloqueado são executados em um motor de indução trifásico para a determinação dos parâmetros do circuito equivalente. O ensaio realizado em condições de carga variável dentro de um intervalo usual de operação do motor, em termos de escorregamento, mostra que o circuito equivalente não representa o comportamento da máquina quando esta trabalha fora do ponto nominal de operação, porque os parâmetros não mais o representam bem naquelas situações de operação. As grandezas obtidas nos ensaios em carga variável são adequadamente condicionadas e utilizadas no treinamento de uma rede neural artificial Multi-Layer Perceptron (MLP). Para a validação dessa rede são comparados os resultados obtidos no modelo neural com os testes experimentais do motor de indução trifásico. / Abstract: This thesis presents a study about the steady state behavior of the three-phase induction motor. The validity of the use of the electric equivalent circuit is discussed when it is utilized on the rated conditions and also on any other operating conditions. No-load and the blocked rotor tests are performed on a three-phase induction motor for the determination of the equivalent circuit parameters. The tests run in variable load conditions in a usual interval of operation of the motor, in terms of slip, show that the equivalent circuit does not represent quit well the behavior of the machine when it works out of the rated point, because the parameters do not represent it in those operating condition any more. The magnitudes obtained in the variable load test are conditioned and used in the training of an artificial neural network Multi-Layer Perceptron (MLP). For the validation of the results, the neural model and experimental tests of the induction motor results are compared. / Mestrado / Automação / Mestre em Engenharia Elétrica

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Electrical machines have been widely used along the last decades with large life length under operating conditions. However, they will become more important in the upcoming years because of the emerging electric car industry. Thus, the maintenance cost of this technology can be reduced by extending the lifetime in the electrical machines. Despite the fact that existing numerous studies within the life length in these devices, only few study the effect of the thermomechanical stresses of insulation. The core of this master thesis is to study the influence of these stresses in the insulation material of a winding. The tested electrical machines were subjected to different test conditions, allowing to analyse multiple aging effects in the winding. To achieve these effects, power cycling tests were carried out on stators, where the windings were tested in cycles with different ΔT and two cooling methods: air cooling and oil cooling. The results showed large aging differences between the two cooling methods employed. The aging effect in the oil cooling method was higher than in the air cooling method for the same number of cycles. However, the aging effects regarding the same cooling process had not wide differences between the different test temperatures.

<p dir="ltr">The most predominantly used rotating electric machines today are the radial and axial flux varieties (denoted RFM and AFM, respectively). There is another category of machines called the transverse flux machines (denoted TFMs) which are best suitable for high torque low speed applications such as in wind energy conversion systems, ship propulsion systems, and other direct drive applications. In this work, a design methodology based on a magnetic equivalent circuit (MEC) model for a three-phase stacked transverse flux machine is presented. Using this MEC model, an optimization-based design paradigm is created. Finite element analysis is used to validate a design obtained from the proposed algorithm. </p>

Knowledge of the end winding inductance of electrical machines is decisive for calculating their operating performance. In this article, two different approaches to analytically calculate the stator end winding inductance of large induction machines are discussed. The first method is based on the exact replication of the 3D conductor geometry using serially connected straight filaments, where the inductances are calculated by solving Neumann’s integral. In the second method, the end winding flux is resolved into components excited by the axial and circumferential end winding magnetomotive force, resulting in a far simpler geometrical model. In both cases, end face effects are taken into account by adopting the method of images. The analytical approaches are compared to the known analytical calculation method proposed by Alger [1]. In addition, the stator end winding inductance is computed by means of 3D finite-element analysis. Using experimental validation, it is shown that both the analytical and numerical results reasonably correlate with removed rotor inductance measurements taken for several induction machines with different rated powers and frame sizes, if the permeability of the laminated core is taken into consideration.