The objective of this thesis is to establish an electromagnetic energy conversion mechanism that is suitable for electric power generation from solar thermal energy. Based on the generator design and thorough electromagnetic path design, a tubular linear generator system design will be proposed. The stator armature with three-phase concentrated windings mounted on a slotless structure is targeted to be implemented for this structure of the generator design, and a special designed of two-segmental Halbach permanent magnet array will be installed on the mover to fulfill the desired tubular linear generator construction. From detailed magnetic equivalent circuit (MEC) analysis and three-dimensional finite element analyses, the feasibility and applicability of the proposed machine system concepts will be verified. Finally, the steady-state operational characteristic of this generator have been estimated cinfirm the design objectives.

The objective of this thesis is to report the concept of driving a non-contacting steel plate conveyance system with a DSP-based closed-loop control structure. The lift force of the system is first estimated from the magnetic equivalent circuit (MEC) analysis, and the estimation results have been verified through three-dimensional finite element analysis (3-D FEA). Based on the force calculations and the fuzzy control theory, a closed-loop control structure has been designed. Through accurate signal detections, a real-time lift force control of the conveyance system can be realized. Finally, by feeding AC sources with DC bias to the stator windings of the motor, the lift and propulsive forces can be supplied to the steel plate simultaneously.

Switched Reluctance Machines (SRMs) are gaining more attention due to their simple and rugged construction, low manufacturing cost, and high-speed operation capability. An electromagnetic model of the machine is needed in the design and analysis processes. The required accuracy level of the model depends mainly on the application. Designing an SRM is an iterative process. Usually, finite element method (FEM) is employed in all design stages, which might require extensive computation burden. The magnetic equivalent circuit (MEC) method is an alternative for typical FEM. MEC models require less computational resources and they can help determine the electromagnetic performance with a reasonable accuracy. The conventional MEC method can be challenging when modifying the motor geometry while conducting dynamic analysis with current control. This thesis proposes a reluctance mesh-based MEC model for SRMs that can overcome those challenges. Reluctance mesh-based MEC models are developed for 3-phase 6/4, 6/16, 12/8 SRMs and 4-phase 8/6, 8/10, and 16/12 SRMs. The implemented MEC-based modeling method is validated using FEM and experimental results. Acoustic noise and vibration is one of the shortcomings of an SRM. The radial force density in the airgap should be calculated before analyzing and mitigating acoustic noise and vibration. This thesis proposes a radial force density calculation method for SRMs using the proposed MEC model. Fourier series is used to calculate the harmonics of the radial force density. The results obtained from the MEC model are verified using FEM models. SRM is a promising candidate for electric propulsion systems. In the design process of an SRM, the motor geometry needs to be determined. This thesis applies the proposed MEC technique to the design process of a 3-phase 12/16 SRM for a high lift motor in the NASA Maxwell X-57 electric aircraft. The design is verified using the results computed from FEM. / Dissertation / Doctor of Philosophy (PhD) / Electric motors are utilized in our daily life in various applications such as washing machines, refrigerators, air conditioners, fans, vacuum cleaners, blenders, and many other devices and tools. Motors are widely used in residential, industrial, commercial, and transportation applications. Due to the environmental impact of burning fossil fuels, transportation systems are moving into electrified propulsion. Electric motors with lower cost and higher efficiency are on the path to replacing the traditional combustion engines in vehicles. Among the different electric motors available, switched reluctance motor (SRM) is becoming a promising candidate in future electrified transportation systems due to their simple construction. Developing a motor is a time-consuming and costly task. Therefore, it is essential to determine the characteristics of an SRM before manufacturing it. A mathematical framework is proposed in this thesis to address this problem. The proposed framework is capable of determining the characteristics of an SRM accurately.

<p>This thesis investigates simulation of synchronous machines using a novel Magnetic Equivalent Circuit (MEC) model. The proposed model offers sufficient detail richness for design calculations, while still keeping the simulation time acceptably short.</p><p>Different modeling methods and circuit alternatives are considered. The selected approach is a combination of several previous methods added with some new features. A detailed description of the new model is given. The flux derivative is chosen as the magnetic flow variable which enables a description with standard circuit elements. The model is implemented in dq-coordinates to reduce complexity and simulation time. A new method to reflect winding harmonics is introduced.</p><p>Extensive measurements have been made to estimate the traditional dq-model parameters. These in combination with analytical calculations are used to determine the parameters for the new MEC model.</p><p>The model is implemented using the Dymola simulation program. The results are evaluated by comparison with measurements and FEM simulations. Three different operation cases are investigated; synchronous operation, asynchronous start and inverter fed operation. The agreement with measurements and FEM simulations varies, but it is believed that it can be improved by more work on the parameter determination.</p><p>The overall conclusion is that the MEC method is a useful approach for detailed simulation of synchronous machines. It enables proper modeling of magnetic saturation, and promises sufficiently detailed results to enable accurate loss calculations. However, the experience is that the complexity of the circuits should be kept at a reasonable low level. It is believed that the practical problems with model structure, parameter determination and the simulation itself will otherwise be difficult to master.</p>

The objective of this thesis is to provide a reliable and effective iron loss estimation scheme for the electromagnetic steel products in the design and on-line operation stages. To investigate the possible performance of electromagnetic steel products, proper iron loss information of the products that are constructed by different steels is one of the key concerns. Along with the various power electronic device applications and iron core structures, the magnetic fluxes flowing through the machine cores will be non-uniform and include harmonic terms. Unless excessive computation efforts in expensive software tools are performed, large discrepancies will be exhibited the estimated and actual values of machine iron losses. To overcome these drawbacks, a rational machine iron loss estimation scheme is proposed. By adopting the iterative magnetic equivalent circuits and the nonlinear magnetic characteristics of the electromagnetic steels, the preliminary operational flux information in the machine is first obtained, and then a numerical Epstein Frame test circuit with magnetizing inductance modeled by Preisach model is applied. With appropriate circuit input voltages devised from preliminary information, the detailed hysteresis inner-loop characteristics resulting from product structures and magnetization harmonics can be properly modeled. Based on the circuit results, the iron losses of electric machines with any operation can be rationally evaluated, and a valuable reference in machine designing can be provided.

This thesis provides a detailed field analysis of a specially designed axial-flow radial-flux permanent magnet motor for cooling fan applications. By implementing an iron strip segment at the stator base, this motor can provide a stable guidance force in its axial direction, such that the operational vibration effects can be minimized and the undesired forces applied onto associated bearing system can be alleviated. Supported by adaptive magnetic equivalent circuit and three-dimensional finite element analyses, the motor operational fluxes and forces can be analyzed. Results show that excellent performance and enhanced reliability objectives can all be achieved.

L’enjeu de la thèse concerne la modélisation électromagnétique des machines synchrones à réluctance, avec comme objectif final : obtenir un modèle suffisamment précis et rapide pour, d’une part, être capable de calculer les ondulations de couple et d’autre part servir pour de l’optimisation dimensionnelle et pouvoir être couplé à un logiciel de type circuit pour tester une loi de commande. Un modèle du type schéma réluctant a été mis en place petit à petit avec validations à chaque étape. La modélisation des échanges dans l’entrefer utilise en final une fonction originale (intégrale de Fermi-Dirac) qui a entièrement été paramétrée avec les dimensions caractéristiques de la machine.Ce modèle de la machine, piloté par les courant, a ensuite été couplé avec un circuit électrique grâce à une interface de transformation tension-courant. Les optimisations réalisées avec ce modèle ont permis de mettre en évidence certains manques dans les contraintes dimensionnelles initiales et, celles-ci corrigées, de montrer que ce modèle était parfaitement utilisable pour cette démarche d’optimisation. / This thesis aims the electromagnetic modeling of synchronous reluctance machines, with a final goal: to obtain a fast and sufficiently accurate model, able to calculate the torque ripple and to be used for optimal machine design and also capable to be coupled to circuit software to test control techniques.A MEC (magnetic equivalent circuit) model was created step-by-step and validated at each step. Final model of the air-gap is based on a function (Fermi-Dirac integral), which has been completely parameterized by machine dimensions. This model of the machine is driven by current; afterwards it was coupled with an electric circuit thanks to a voltage-current transformation interface. The optimizations made with the model allowed to highlight some deficiencies in the initial dimensional constraints. After corrections the model could be efficiently used in an optimization process.

No description available.

La traction hybride et/ou électrique est un domaine d’application en pleine croissance présentant une forte restriction en termes d’encombrement. Cela a poussé les concepteurs à créer des structures de machine adaptées. Parmi ces topologies, nous trouvons les machines synchrones à double excitation (MSDE). Ces machines permettent de combiner les avantages d’une machine à aimants et ceux d’une machine à excitation bobinée. Le choix d’un modèle pour ces machines est un élément important dans les étapes d’analyse, d’optimisation et de pré-dimensionnement. Ce mémoire présente une contribution à la modélisation des machines synchrones à simple et à double excitation basée sur la méthode des réseaux de perméances. Trois parties sont ainsi proposées. La première partie de la thèse présente deux états de l’art- un sur les machines synchrones à double excitation et l’autre sur les méthodes de modélisation des machines électriques et principalement la modélisation par réseau de perméances. Dans la deuxième partie, nous abordons la modélisation 2D de la machine synchrone à aimants permanents à concentration de flux avec prise en compte de la rotation et de la saturation. Le but de cette partie est de trouver des méthodes permettant de combiner à la fois temps de calcul et précision. On commence par la modélisation par réseau de perméances en se basant sur un maillage de l’espace d'étude par des réluctances bidirectionnelles, ainsi qu’une comparaison entre calcul du couple par le tenseur de Maxwell et flux-FMM. La deuxième section présente un couplage entre réseaux de perméances et éléments finis. La méthode proposée consiste à résoudre les deux modèles (réluctant et éléments finis) simultanément avec un logiciel EF. Le couplage s’effectue par une équivalence entre les dimensions géométriques et les caractéristiques magnétiques des matériaux. La présentation des différents modèles dans le plan précision-temps de calcul montre l’efficacité de l’utilisation des réseaux de perméances et du couplage comparé au modèle éléments finis. La troisième partie porte sur la modélisation tridimensionnelle des machines synchrones à double excitation. Dans un premier temps, nous présentons une adaptation de la modélisation par réseau de perméances aux structures tridimensionnelles. Puis, nous appliquons ce modèle aux machines synchrones à double excitation. La machine à double excitation à concentration de flux est présentée avec une étude de l’influence du feuilletage sur la capacité de contrôle du flux. Pour améliorer le contrôle du flux d'excitation, une machine à aimants enterrés homopolaire est également étudiée avec l'approche développée. La validation du modèle est réalisée par des éléments finis et des mesures expérimentales. Dans la dernière partie, une comparaison entre configurations homopolaire et bipolaire de la structure à aimants enterrés est effectuée, puis le rotor à concentration de flux est optimisé afin de le comparer à la machine à aimants enterrés. / The electric and / or hybrid driveis are an application area growing with a strong restriction in terms of congestion. This prompted the designers to create appropriate structures. Among these topologies, we find the double-excitation synchronous machine (MSDE). These machines can combine the advantages of permanent magnets machine and those of a coils excited machine.The choice of a model for these machines is an important step in the analysis, optimization and pre-sizing. This thesis presents a contribution to the modeling by magnetic equivalent circuit (MEC) of single and double excitation synchronous machines. Three parties are offered as well. The first part of the thesis presents two states of the art: one on the double-excitation synchronous machines and the other on the modeling of electrical machines, mainly in the modeling by magnetic equivalent circuit. In the second part, we discuss the 2D modeling of flux concentration permanent magnet synchronous machine taking into account the rotation and saturation. The purpose of this section is to find ways to combine both computational time and accuracy. We start by using the magnetic equivalent circuit modeling based on a mesh of the structure and each mesh is replaced by two-way reluctances, then a torque estimation are obtened by two methods flux-FMM and Maxwell stress Tensor. The second section presents a coupling between magnetic equivalent circuit and finite element method. The proposed method is to solve the two models (reluctant and finite elements) simultaneously with software EF. The coupling is performed by an equivalence between the geometric dimensions and magnetic properties of materials. The presentation of different models in terms of time-accurate calculation shows the effectiveness of the use of MEC and coupling method compared to FEM. The third part concerns the three-dimensional modeling of double excitation synchronous machines. At first, we present an adaptation of the MEC to the three-dimensional structures. Then we apply this model to the double excitation synchronous machines (DESM). The DESM with flux concentration configuration is presented. To better control the wund flux of excitation, a buried magnet homopolar machine is also studied with the same approach. Model validation is performed by finite element and experimental measurements. In the last part, a comparison between homopolar and bipolar configurations is made, then the rotor flux concentration is optimized in order to compare it to the machine magnets buried.

This thesis investigates simulation of synchronous machines using a novel Magnetic Equivalent Circuit (MEC) model. The proposed model offers sufficient detail richness for design calculations, while still keeping the simulation time acceptably short. Different modeling methods and circuit alternatives are considered. The selected approach is a combination of several previous methods added with some new features. A detailed description of the new model is given. The flux derivative is chosen as the magnetic flow variable which enables a description with standard circuit elements. The model is implemented in dq-coordinates to reduce complexity and simulation time. A new method to reflect winding harmonics is introduced. Extensive measurements have been made to estimate the traditional dq-model parameters. These in combination with analytical calculations are used to determine the parameters for the new MEC model. The model is implemented using the Dymola simulation program. The results are evaluated by comparison with measurements and FEM simulations. Three different operation cases are investigated; synchronous operation, asynchronous start and inverter fed operation. The agreement with measurements and FEM simulations varies, but it is believed that it can be improved by more work on the parameter determination. The overall conclusion is that the MEC method is a useful approach for detailed simulation of synchronous machines. It enables proper modeling of magnetic saturation, and promises sufficiently detailed results to enable accurate loss calculations. However, the experience is that the complexity of the circuits should be kept at a reasonable low level. It is believed that the practical problems with model structure, parameter determination and the simulation itself will otherwise be difficult to master.