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International audience; A complete and generic medium frequency transformer (MFT) design methodology is presented in this paper, which can be applied to many transformer structures. Models were found or developed to cover every necessary calculation, with a focus on the balance between computation time and accuracy, leading to a fast and efficient design tool. A lot of MFT designs are available at the end and the possibility to choose the best candidate is offered. A multi-megawatt offshore windfarm converter application has been chosen to show the design optimization procedure of the MFT inside such a converter. The best potential design found is then validated by numerous finite element simulations to validate the models used. This procedure is then repeated for various MFT structures in order to realize a quantitative comparison of many different technological choiceschoices' combinations. This study can give insights on the best technological choices to be used for MFT, and also shows significant differences on performances between structures.

International audience; The magnetic needle probe method is a technique used to locally measure the magnetic state of a magnetic component. This concept has a rich conceptual history, but it has rarely been used in the industrial field. There are mainly two reasons for this: instrumentation limitations and inappropriate sizes of sensors’ geometries. The first limitation has been overcome recently due to large improvements in both the analog and digital electronic fields. In this study, the second limitation, size/geometry is addressed by printing the magnetic needle probe using conductive ink directly on the ferromagnetic element to be controlled. The resulting sensor exhibits a drastic volume reduction. Such improvements allow measurement of the magnetic state of a previously inaccessible magnetic lamination through a magnetic laminated core. This opens up the possibility of measuring in situ magnetic behavior and monitoring many electromagnetic devices such as electric transformers, AC/DC electric motors, or even real-time electromagnetic non-destructive testing of ferromagnetic steel components. Over the past few years, simulation approaches including space discretization methods: finite elements, finite differences, and boundary elements have been proposed to describe the internal behavior of magnetic lamination stacks but experimental results validating these simulations could not be realized due to the aforementioned limitations. The printed magnetic needle probe method (PMNPM) described in this paper can be used to collect such local information and to validate homogenization methods. Experimental validations are proposed by comparing the sum of the laminations magnetic induction, they are individually measured with the PMNPM method to calculate the average induction obtained from a surrounding coil.

International audience; Increasing the energy efficiency is one of the most important issues in modern power electronic systems. In aircraft applications, the energy efficiency must be associated with a maximum reduction of mass and volume, so a high components compactness. A consequence from this compactness is the increase of operating temperature. Thus, the magnetic materials used in these applications, have to work at high temperature. It raises the question of the thermal ageing problem. The reliability of these components operating at this condition becomes a real problem which deserves serious interest. Our work takes part in this context by studying the magnetic material thermal ageing. The nanocrystalline materials are getting more and more used in power electronic applications. Main advantages of nanocrystalline materials compared to ferrite are: high saturation flux density of almost 1.25 T and low dynamic losses for low and medium frequencies. The nanocrystalline Fe73.5Cu1Nb3Si15.5B7 alloys have been chosen in our aging study. This study is based on monitoring the magnetic characteristics for several continuous thermal ageing (100, 150, 200 and 240 °C). An important experimental work of magnetic characterization is being done following a specific monitoring protocol. Elsewhere, X-Ray Diffraction and magnetostriction measurements were carried out to support the study of the anisotropy energies evolution with ageing. This latter is discussed in this paper to explain and give hypothesis about the ageing phenomena.

International audience; An alternative sensing solution is described to measure local magnetic hysteresis cycles through a laminated magnetic core. Due to the reduced space gap separating two successive laminations, it is impossible to interpose the usual oversize magnetic sensors (wound coil, Halleffect sensor). In this study, the space issue has been solved by printing the needle probe method for the magnetic state monitoring and by using a micrometric Giant Magneto Resistance (GMR) for the magnetic excitation measurement. An instrumented magnetic lamination including the non-invasive monitoring solution has been built and moved successively to every lamination position of the whole laminated ferromagnetic core. A precise cartography of the hysteresis losses has been reconstructed from all these local measurements and the average values compared to the classic measurement methods obtained with a wound coil. The relative agreement between the experimental results observed opened doors to large improvement in the estimation of magnetic losses and in the design of magnetic circuits.

International audience; Leakage inductance and frequency-dependent resistance of windings are key parameters for the design of magnetic devices. This report focuses on analytical or semi-analytical calculation techniques to be integrated into a medium frequency transformer optimization process. To this extend, a review of currently most used method to calculate inductance and resistance of windings transformer is established. Based on this review, new calculation methods are developed. Magnetic field cartography is evaluated on the basis of two-dimensional structures thanks to a combination of Ampère's law and image method. From this magnetic field map, leakage inductance can be calculated. The obtained accuracy with this method is equivalent to three-dimensional finite element modeling. For frequency-dependent resistance evaluation, new methods based on two-dimensional or one-dimensional approach are compared to finite element modeling and reviewed models. An analysis of behavior of each model is done, showing that newly developed models are more suitable in the case of medium frequency transformer design in terms of accuracy, robustness and calculation time. This work could be useful to magnetic devices designers because newly developed models could easily be adapted to various geometries, such as toroidal structures or even inductors.

International audience; In power electronics applications, magnetic components are often subjected to nonsinusoidal waveforms, variable frequencies, and dc bias conditions. These operating conditions generate different losses in the core compared to sinusoidal losses provided by manufacturers. In the conception and design stage, lack of precise losses diagnosis has unacceptable effects on sys-tem's efficiency, reliability, and power consumption. Since virtual prototyping is used to predict and improve system's behavior before realization, losses and behavior prediction of components is possible. Circuit simulators and their compatible components models are required. This paper is summarized by proposing nonlinear dynamic model of powdered material magnetic core for use in circuit simulators. It includes the material's nonlinear hysteresis behavior with accurate winding and core modeling. The magnetic component model is implemented in circuit simulation software " Simplorer " using VHDL–AMS modeling language. Waveforms and losses of a powder core inductor in a buck converter application are simulated and compared to measured ones. The model is validated for different ripple currents, different loads, and a wide frequency range. DC bias is taken into account in both continuous and discontinuous conduction modes.

International audience; Nanocrystalline materials have very low losses compared to standard iron-silicium, amorphous materials and can work at higher inductions than ferrite materials. It makes them a good candidate for high power medium frequency transformer applications. However, manufacturing processes such as impregnation or cut significantly increase magnetic losses, as shown previous studies. Some other manufacturing processes of nanocrystalline cores can also impact magnetic properties. The core shape (toroidal, oval, C-core), the ribbon width and the ribbon shearing impact on magnetic properties will all be studied. For each of these cases, magnetic properties will be evaluated before and after impregnation and cut because these manufacturing processes have a huge impact on magnetic properties and can be coupled to the new manufacturing processes we want to study in this paper. The objectives of this study are to, firstly, be able to make a better choice of nanocrystalline cores and secondly, know how to build efficient high power medium frequency transformers with such materials. Some results in terms of losses are available on Fig. 1. These results concern cores made of sheared or unsheared nanocrystalline ribbon. Three cores of each (total of 6) have been tested. The Fig. 1 represents the average of losses density versus frequency for three induction levels. In each case, sheared cores seems to have slightly higher losses (average 11% and 21% maximum). Complex permeability versus frequency results are shown in Fig. 2. In this case, all curves of all cores are presented. Measurements have shown that the shearing of the nanocrystalline ribbons increase the losses and the permeability, while reducing the scattering between samples. The extended article will present details of how the results are obtained and some other results. One can cite the ribbon width (8 mm, 15 mm, 25 mm) and the core shape (toroidal, rectangular and oval) influence on magnetic properties.

International audience; Medium frequency transformers are an essential part of new energy conversion systems, and are very often subject to non-sinusoidal excitation. Therefore, usual methods to represent magnetic materials behavior inside transformers with electrical equivalent scheme are very limited in this case. This paper focuses on the development of a new model based on the loss separation method. This model is implemented in a circuit simulation software with the VHDL-AMS modeling language to represent the behavior of a flux tube: non-linearity, hysteresis and losses. It allows to obtain relevant results for any excitation waveform as the model is temporal. The developed model was compared with experimental results on a small-scale nanocrystalline transformer prototype and it remains very accurate regarding the hysteresis cycle shape and core losses over a wide frequency range, and also for different waveforms.

International audience; It is found to be one of the major issues while designing an aircraft, mass and volume have to be reduced in order to achieve energy efficiency. This leads to a high compactness of the electrical components which enables them to withstand at high temperatures. The magnetic components which are responsible for the electrical energy conversion, therefore exposed to high temperatures in working conditions. Their thermal ageing becomes a serious problem and deserves a particular attention. The FeCuNbSiB nanocrystalline materials have been selected for this ageing study because they are used in power electronic systems very frequently. The objective of the study is based on monitoring the magnetic characteristics under the condition of several continuous thermal ageing (100, 150, 200 and 240 °C). An important, experimental work of magnetic characterization is being done through a specific monitoring protocol and X-ray diffraction (XRD) along with magnetostriction measurements was carried out to support the study of the evolution of the anisotropy energies with aging. The latter is discussed in this paper to explain and give the hypothesis about the aging phenomena.

International audience; In the future, medium-frequency transformers (with a frequency range of 5-100 kHz) will be major components in dc-dc converter applications, for both medium-voltage direct current and high-voltage direct current networks. Importantly, the corresponding power losses should be accurately calculated in order to reach performance targets (very high efficiency). This paper reviews the most known analytical models that are used to calculate the medium-frequency resistance for several winding technologies. In order to qualify these models in a future design flow, we compare the analytical model results with measurements and 3-D finite-element electromagnetic simulations and the impact on the warming. The adopted design flowchart has been tested on a 17-kHz 180-kVA prototype transformer that will be used in a dual active bridge.

International audience; Since their birth or mergence the late 1980s, the nanocrystalline ultrasoft magnetic materials are taking a great importance in power electronic systems conception. One of the main advantages that make them more attractive nowadays is their ability to be packaged since the reduction of the magnetostrictive constant to almost zero. In aircraft applications, due to the high component compactness and to their location (for example near the jet engine), the operating temperature increases and may reach easily 200 °C and more. Consequently, the magnetic thermal ageing may occur but is, unfortunately, weakly studied. This paper focuses on the influence of the coating (packaging type) on the magnetic nanocrystalline performances during a thermal ageing. This study is based on monitoring the magnetic characteristics of two types of nanocrystalline cores (naked and coated) during a thermal activated ageing (100, 150 and 200 °C). Based on a dedicated monitoring protocol, a large magnetic characterization has been done and analyzed. Elsewhere, X-Ray Diffraction and magnetostriction measurements were carried out to support the study of the anisotropy energies evolution with ageing. This latter is discussed in this paper to explain and give hypothesis about the ageing phenomena.

Nos remerciements à IEEE pour l'autorisation de mise à disposition du papier complet. © IEEE Copyright Notice : Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.; International audience; Electromagnetic relay modeling is elaborated using a magnetic equivalent circuit (MEC). The lumped parameters of the MEC are fitted with respect to 3-D finite-element simulation by using classical optimization algorithms. An accurate dynamic material law has to be taken into account in the modeling, considering the massive core of the circuit. Two accurate dynamical models for representing eddy currents are studied. The simulation of the relay is carried out for several excitation frequencies. A comparison between measurements and simulated quantities is provided.

PurposeThe purpose of this paper is to analyze the main assumption of a dynamic flux tube model and to define its rules of use.Design/methodology/approachThe studied dynamic model lumps together all dynamic effects in the circuit by considering a single dynamic parameter. A physical meaning of this parameter as well as rules of use of the model are elaborated from analyses performed on several samples. A systematic comparison between experimental and calculated results allows to argue the conclusions.FindingsThe model gives accurate results when a weak heterogeneity of magnetic data exists, nevertheless, the saturation phenomenon enlarges the validity domain. By considering the losses separation assumption, the model allows to obtain separately an estimation of losses due to classical eddy currents and due to the wall motion effects.Research limitations/implicationsThe estimation of the model's parameter value is still empiric, a work is in progress on this subject.Practical implicationsThe model's implementation in a flux tubes network allows to simulate the dynamic behaviour of industrial actuators having massive cores.Originality/valueA physical interpretation of the parameter associated to the dynamic flux tube model is given. Rules of use of the model are also defined.

International audience; Some soft magnetic materials are strongly dependent of the temperature, because of their low Curie temperature. In order to predict their behavior in electrical devices, engineers need hysteresis models able to take into account the temperature. This paper is an attempt to take into account the temperature in an existing model of static hysteresis through its parameters. Variations of some parameters with temperature are issued or build thanks to the literature. At the end, all needed parameters have an analytical law versus temperature. Simulation results are compared to measurements and discussed.

International audience; In the future, Medium Frequency Transformers (MFT with a frequency range 5 kHz to 100 kHz) will be major components in DC-DC converter applications, for both Medium Voltage Direct Current (MVDC) and High Voltage Direct Current (HVDC) networks. Importantly, the corresponding power losses should be accurately calculated in order to reach performance targets (very high efficiency). This paper reviews the most known analytical models which are used to calculate the medium frequency resistance for several winding technologies. In order to qualify these models in a future design flow, we compare the analytical model results with measurements and 3D finite element (3DFE) electromagnetic simulations and the impact on the warming. The adopted design flow-chart has been tested on a 17 kHz – 180 kVA prototype transformer that will be used in a Dual Active Bridge (DAB).

International audience; Nowadays, nanocrystalline soft magnetics materials for high power applications receive more and more consideration. Nevertheless, some technological parameters can have an influence of potential significance on the performances (losses, permeability, frequency behavior…). One main drawback of the nanocrystalline materials is their brittleness. To prevent this effect in order to handle the Magnetic Circuit (MC), it is preferable to impregnate it with varnish. Moreover, thanks to the impregnation, the MC can be cut in order to insert the winding. In this paper, the influence of various technological manufacturing processes on the magnetic properties of nanocrystalline cores is studied. Firstly, nanocrystalline magnetic cores of the same size, without impregnation and with three different varnishes, are experimentally characterized with a hysteresigraph (from DC to 1 MHz). Secondly, the same MC were cut in and characterized again. This protocol gives information about the influence of the varnish employed and on the cut separately. The results also help the end-user to choose the " best " technological processes for its application (example: medium frequency transformer (MFT))

International audience; Some soft magnetic materials (like ferrites but not only) are strongly dependent of the temperature. In order to predict their behaviour in electrical devices, engineers need hysteresis models able to take into account the temperature. This paper is an attempt to take into account the temperature in an existing model of hysteresis through its parameters. Variations of some parameters are issued from Weiss’s works and others have to be fitted numerically. Simulation results are compared to measurements and discussed.

International audience; In the design of such power electronics applications as power converters, lack of precise characterization and diagnosis of losses from components has unacceptable effects on efficiency, reliability, and power consumption. Because passive components, especially magnetic components, are crucially important in power converters, accurate characterization and modeling of magnetic materials is mandatory, to enable realistic prediction of their behavior under variable operating conditions. Temperature is one such condition that induces major changes in a component’s behavior by modifying the material’s magnetic properties. In the work discussed in this paper we investigated the magnetic and thermal behavior of nanocrystalline and powder materials in a DC–DC converter application. Core loss measurements under variable conditions were performed on toroid-shaped samples. Measured results were analyzed for different frequencies, flux densities, and temperatures.

International audience; The introduction of accurate material modeling such as hysteresis phenomenon in numerical field calculation leads to numerical problems induced by the nonlinear properties of the initial system. We focus on the solution of the magnetic field diffusion equation, which contains such problems. This paper presents a new formulation of the diffusion equation including dynamic hysteresis. The resulting formulation leads to a linear system to solve. A numerical implementation of the problem and an experimental validation are also presented.

National audience; Cet article a pour but de présenter une synthèse des études des dernières années faites autour de la caractérisation et de la modélisation des matériaux et composants magnétiques sous contrainte thermique. Les études présentées sont notamment, mais pas exclusivement, issues des travaux du laboratoire AMPERE et plus particulièrement de l'équipe "matériaux pour le génie électrique".

International audience; In power electronics applications, magnetic components are often subjected to non-sinusoidal waveforms, variable frequencies and DC bias conditions. These operating conditions generate different losses compared to sinusoidal losses provided by manufacturers. Since virtual prototyping is used to predict and improve system's behavior before realization, losses and behavior prediction of components is required. Circuit simulators and their compatible components models are required. This work is summarized by proposing non-linear dynamic model of magnetic components for use in circuit simulators. It includes the material's nonlinear hysteresis behavior with accurate winding and core modeling. The magnetic component model is implemented in circuit simulation software " Simplorer " using VHDL-AMS modeling language. Waveforms and losses of a powder core inductor in a buck converter application are simulated and compared to measured ones.

International audience; Virtual prototyping is essential in the development of new power electronics devices like transformers and static power converters. Circuit simulators as SPICE and SIMPLORER allow the optimization of complex circuit prototypes by associating models of passive and active components. Magnetic components constitute a major part of electronics devices, therefore accurate modeling of magnetic materials is mandatory in order to predict their realistic behavior under variable operating conditions. In fact nonlinear characteristics of magnetic materials in addition to dynamic and thermal effects have a non-negligible influence on device's performance and must be taken into account in circuit simulations [1]. This paper takes place in this context by proposing a non-linear dynamic model of magnetic components for use in circuit simulators. It includes the material's nonlinear hysteresis behavior with accurate modeling of winding and core losses in addition to thermal effects that are not taken into account by existing models. The model is based on the principle of separation of static and dynamic contributions as well as Bertotti's theory [2]. In the interest of precision and in order to be adaptable for different types of magnetic materials, the magnetic component model adopts structural modeling approach. As a consequence the model consists of 3 major blocks as shown in the adjacent figure: a winding responsible for coupling between electrical and magnetic domains using Ampere's and Faraday's laws, a static model to describe the static hysteresis behavior of the magnetic material and a dynamic model to add classical and excess losses in the core. Each of these blocks is described using VHDL-AMS [3] modeling language due to its multi-domain modeling feature, allowing coupling with a thermal model. The thermal model can be represented by a simple temperature source for static thermal conditions or by an equivalent thermal circuit for self-heating conditions. The magnetic component model is validated by modeling a Nanocrystalline-core inductor. The appropriate choice of static law able to describe the piecewise linear static behavior of the material is presented. The identification of static and dynamic models parameters is discussed. Thermal effects are investigated, by predicting the model's parameters variation as function of temperature. The effects of frequency and waveform are also studied.

International audience; The presented work constitutes a contribution to dynamic behavioural models of the magnetic circuits of electrical actuators. We propose an original model for the representation of the microscopic dynamic effects in the magnetic materials. This model attached together with the classic magnetic field diffusion equation resolution allows to describe completely the whole dynamic effects in a magnetic lamination. This model which needs only one parameter penalises a little the calculation time respect to the improvement of the results. An experimental validation considering different wave-form excitations and frequencies has shown that this parameter can be assumed as constant for a wide area of excitation solicitations.

La connaissance du comportement dynamique des materiaux magnetiques est importante pour l'evaluation des pertes fer dans les machines electriques. Pour les sollicitations simples d'une tole dans un cadre Epstein ou un tore fin, la resolution de l'equation de la diffusion du champ magnetique dans le plan de la section de la tole limitee aux seuls courants de Foucault, ne fournit qu'une description insuffisamment precise des phenomenes. Cet article presente une methode simple de prise en compte des phenomenes dynamiques locaux dans l'equation de diffusion. L'etude sera limitee a des sollicitations de premiere aimantation dynamique. Une validation experimentale de ce modele en fonction de la frequence est aussi presentee.

International audience; The aim of this study consists in modeling the magnetic behavior of a nanocrystalline material, taking into account temperature variation. Indeed the development of power electronic embedded systems leads to increase the operating temperature range. Besides nanocrystalline material is used more and more in such systems, so temperature influence is a key point in the magnetic component design.

International audience; The aim of this study consists in comparing the contributions of two static hysteresis models (chemical" model and Jiles-Atherton's) in dynamic representation of magnetic behaviour using the magnetic diffusion problem. To improve the performance of both static hysteresis models in the magnetic diffusion equation, it has been homogenized and tests have been performed on a toroidal core of non-oriented FeSi sheets. The material has been excited at a rather low frequency in order to avoid the skin effect. Tests have been made first for excitations leading to major loops then for specific waveforms to obtain minor loops and recoil lines. Results for both models are quantified in terms of accuracy, convergence and computing time. Cet article compare les apports des modèles d'hystérésis statiques " chimique " et de Jiles-Atherton pour la représentation dynamique d'un matériau par la diffusion magnétique. Afin de mettre en valeur les performances de chacun des deux modèles d'hystérésis statiques dans l'équation de diffusion magnétique, cette dernière est homogénéisée et des tests sont effectués sur un échantillon torique constitué d'un empilement de rondelles de FeSi à GNO de faible épaisseur. Le matériau est excité à une fréquence réduite afin de ne pas provoquer l'apparition de l'effet de peau. Des essais sont opérés dans un premier temps pour des excitations conduisant à des cycles majeurs et mineurs centrés puis, dans un deuxième temps, pour des formes d'ondes particulières amenant à l'obtention de cycles de recul ou de boucles mineures décentrées. Les résultats obtenus pour les deux modèles sont quantifiés en termes de précision, de convergence et de temps de calcul.

International audience; The aim of this study consists in modelling the magnetic behaviour of a nanocrystalline material taking into account temperature variation. Indeed the development of power electronic embedded systems leads to increase the operating temperature range. Besides nanocrystalline material is more and more used in such systems, so temperature influence is a key point in the inductance design.

International audience; The aim of this study consists in comparing the contribution of two static hysteresis models ("chemical" and Jiles-Atherton models) in dynamic representation of magnetic behaviour using the magnetic diffusion equation. It has been homogenised and tests have been performed on a toroidal core of non-oriented FeSi sheets. The material has been excited at a rather low frequency in order to avoid the skin effect. First results are given by considering excitation fields leading to major loops then minor loops.

International audience; In this work we present an original magnetic hysteresis model with parameters fitted from measured reversal curves. This model is used together with the Finite Element method for studying a structure composed of a magnetic core with air-gap excited by a coil.

National audience

International audience; The design of differential breakers is a delicate work which requires a lot of precautions because they ensure life and property safety. Before building new prototypes, the first step is to model the system. The modelling of such a system must have a large validity domain and take into account complex phenomena (hysteresis, eddy currents,. . . ). In this paper, we analyse more particularly the current sensor. This part is essential in order to transmit the fault signal. The robust and temporal model used is tested with several different fault signals mentionned in the differential breaker specifications. La conception de disjoncteurs différentiels est une tâche délicate pour laquelle de nombreuses précautions doivent être prises car les disjoncteurs assurent la protection des biens et des personnes. L'élaboration de nouveaux prototypes passe par l'étape préalable et indispensable de leur modélisation. Celle-ci doit avoir un domaine de validité large et prendre en compte des phénomènes complexes (hystérésis, courants induits...). Dans cet article, nous analysons plus particulièrement le capteur de courant, organe essentiel dans la transmission du signal de défaut. Le modèle robuste et temporel utilisé est testé avec différentes sollicitations spécifiques stipulées dans le cahier des charges du disjoncteur différentiel.

Nos remerciements à IEEE pour l'autorisation de mise à disposition du papier complet. © IEEE Copyright Notice : Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.; International audience; This paper presents the use of the multiobjective particle swarm optimization (PSO) technique for the identification of Jiles–Atherton model parameters. This approach, implemented for the first time in order to solve this kind of problem, is tested for two magnetic materials: NO 3% iFe and NiFe 20–80. The results are compared with those obtained with a direct search method and a genetic algorithm procedure. Experimental measures performed on both samples of materials allow us to complete and argue the validation for the PSO method.

International audience

International audience; In order to ensure life safety, differential circuit breakers are employed. These devices are usually made of different parts. One of the part that will be described in this paper is the electromagnetic relay. This actuator must be modelled with a great accuracy in order to predict if the circuit breaker will open if an eventual fault occurs. In this paper, we focus on the modelling of the geometry of the electromagnetic relay and of its static behaviour. A tripping criterium and different optimization results of the model parameters will be discussed..

International audience; La modélisation du comportement magnétique dynamique des circuits homogènes (tôle de cadre Epstein) est bien maîtrisée ; l'application de ces modèles à des circuits inhomogènes est plus délicate. Des outils numériques, basés sur du calcul de champ 2D existent et prennent en compte l'hystérésis et de façon globale les effets des courants de Foucault. Nous proposons une nouvelle approche de modélisation en dynamique de circuits magnétiques inhomogènes. Cette modélisation fournit des informations temporelles en tout point de l'épaisseur du circuit et nécessite un temps de calcul particulièrement réduit.

International audience; In order to ensure life safety, differential circuits breakers are employed. These devices are usually made of different parts. One of the parts that will be described in this paper is the electromagnetic relay. The actuator must be modeled with a great accuracy in order to predict if the circuit breaker will open of an eventual fault occurs. In this paper, the dynamical behavior of the relay is studied. Two accurate dynamical laws of the magnetic material are taken into account and tested.

International audience; Nowadays, nanocrystalline soft magnetics materials for high power applications receive more and more consideration. Nevertheless, some technological parameters can have an influence of potential significance on the performances (losses, permeability, frequency behavior…). One main drawback of the nanocrystalline materials is their brittleness. To prevent this effect in order to handle the Magnetic Circuit (MC), it is preferable to impregnate it with varnish. Moreover, thanks to the impregnation, the MC can be cut in order to insert the winding. In this paper, the influence of various technological manufacturing processes on the magnetic properties of nanocrystalline cores is studied. Firstly, nanocrystalline magnetic cores of the same size, without impregnation and with three different varnishes, are experimentally characterized with a hysteresigraph (from DC to 1 MHz). Secondly, the same MC were cut in and characterized again. This protocol gives information about the influence of the varnish employed and on the cut separately. The results also help the end-user to choose the " best " technological processes for its application (example: medium frequency transformer (MFT))

International audience; This paper presents a magnetic circuit modeling of closed loop Hall-effect current sensors based on a magnetic equivalent circuit which could be simulated with a circuit type simulator software (PSPICE model). First, the principle of measurement of the closed loop Hall-effect current sensors is presented, Then, the magnetic equivalent circuit (MEC) modeling justified by the engineers' model needs is elaborated. Finally the parameters identification protocol based on 3D Finite-Elements (FE) simulations and simplex optimization method is explained.

National audience; Un modèle simple de comportement dynamique de circuit magnétique élémentaire en vue d'une implantation aisée dans des modèles de dispositifs électromagnétiques basés sur du calcul de champs ou sur une approche de schémas de réluctances est présenté. Ce modèle provient d'une homogénéisation simplifiée d'un modèle complet de diffusion magnétique incluant les effets dus aux mouvements de parois. Le modèle de diffusion complet homogénéisé obtenu n'est rien d'autre que le modèle global de représentation dynamique de circuit élaboré il y a plusieurs années dans notre laboratoire. L'intérêt de cette homogénéisation est d'apporter une signification et une identification de la valeur du paramètre associé au modèle global obtenu. Des tests effectués sur plusieurs échantillons de matériaux différents permettent de définir les critères associés au domaine de validité et d'utilisation du modèle global de représentation de circuit présenté

Medium Frequency Transformers (MFT) are an innovative technology compared to low frequency transformers, with the promise of reduced volume and increased efficiency. This PhD thesis focuses in particular on their design for high voltage, high power applications, such as high voltage and medium voltage DC networks, as well as railway networks. In these applications, MFTs are used in converters that can generate specific constraints to be taken into account during their design: non-sinusoidal signals, polarization voltage, target inductance values. Moreover, the technological choices currently available for the realization of MFTs are numerous, and there is currently no consensus on any technology for any given application. Trends could be identified using a tool to classify MFT designs from the literature. Thus, the most promising technologies were selected and retained for the future. Based on these technologies, a design methodology was developed to quickly and semi-automatically design and compare MFTs with different technological choices. It consists of three steps: pre-design, analytical design, and validation. The complete analytical design of the MFT with different technological choices is carried out using an automated design tool developed during this thesis, named SUITED (SUpergrid Institute TransformEr Design). This methodology requires models and data for each of the components and phenomena of the MFT. Concerning the magnetic core, a review and selection of models from the literature were carried out for the evaluation of the magnetizing inductance and magnetic losses. In addition, magnetic characterizations have made it possible to highlight the impact of certain technological processes on the levels of loss of magnetic cores made of nanocrystalline material, which is an excellent candidate for MFTs. Concerning the windings, analytical models to calculate the magnetic field, leakage inductance and skin and proximity effects were developed and compared with those in the literature and simulations. These models are proving to be more accurate on the MFT geometries considered. On top of that, a new method for evaluating the parasitic capacitances of windings with rectangular turns has been successfully implemented and validated. Thermal networks have been identified for the different MFT geometries. The thermal resistances of conduction, convection and radiation are calculated from detailed models. In particular, the anisotropy of materials is taken into account for thermal conduction, and the convection coefficients are evaluated via different correlations for each face of the MFT. The thermal networks are then solved iteratively and analytically to take into account the non-linearity of the thermal resistances while optimizing the required computation time. Finally, this entire design methodology was applied to three case studies corresponding to the target applications: high voltage, medium voltage and rail. The results obtained do show the performance and necessity of this approach., Les Transformateurs Moyenne Fréquence (TMF) sont une technologie innovante par rapport aux transformateurs basse fréquence, avec la promesse d’une réduction de volume et d’une augmentation du rendement. Cette thèse s’intéresse en particulier à leur conception pour des applications haute tension forte puissance, telles que les réseaux haute tension et moyenne tension à courant continu, ainsi que les réseaux ferroviaires. Dans ces applications, les TMF sont utilisés au sein de convertisseurs pouvant générer des contraintes spécifiques à prendre en compte durant leur conception : signaux non-sinusoïdaux, tension de polarisation, valeurs d’inductances cibles. De plus, les choix technologiques actuellement disponibles pour la réalisation des TMF sont nombreux, et aucun de ces choix ne fait actuellement consensus quelle que soit l’application visée. Des tendances ont pu être identifiées à l’aide d’un outil de classification des designs de TMF issus de la littérature. Ainsi, les technologies les plus prometteuses ont été sélectionnées et retenues pour la suite. A partir de ces technologies, une méthodologie de conception permettant de concevoir et comparer rapidement et ce de façon semi-automatique des TMF avec différents choix technologiques a été mise en place. Elle est constituée de trois étapes : pré-design, design analytique et validation. Le design analytique complet du TMF avec différents choix technologiques est réalisé à l’aide d’un outil de conception automatisée développé durant cette thèse, que nous avons nommé SUITED (SUpergrid Institute TransformEr Design). Cette méthodologie requiert des modèles et données pour chacun des composants et phénomènes du TMF. Concernant le noyau magnétique, une revue et une sélection de modèles issus de la littérature ont été effectuées pour l’évaluation de l’inductance magnétisante et des pertes magnétiques. De plus, des caractérisations magnétiques ont permis de mettre en évidence l’impact de certains procédés technologiques sur les niveaux de pertes de noyaux magnétiques en matériau nanocristallin, qui est un excellent candidat pour les TMF. Au niveau des bobinages, des modèles analytiques pour calculer le champ magnétique, l’inductance de fuite et les effets de peau et de proximité ont été développés et comparés avec ceux de la littérature ainsi que des simulations. Ces nouveaux modèles s'avèrent obtenir une meilleure précision sur les géométries de TMF considérées que ceux de la littérature. De plus, une nouvelle méthode d’évaluation des capacités parasites de bobinages à spires rectangulaires a été mise en place et validée avec succès. Des schémas thermiques équivalents ont été identifiés pour différentes géométries de TMF. Les résistances thermiques de conduction, convection et radiation sont calculées à partir de modèles détaillés. En particulier, l’anisotropie des matériaux est prise en compte pour la conduction thermique, et les coefficients de convection sont évalués via des corrélations différentes pour chaque face du TMF. Les schémas thermiques sont ensuite résolus de façon itérative et analytique pour prendre en compte les non-linéarités des résistances thermiques tout en optimisant le temps de calcul nécessaire. Enfin, l’ensemble de la méthodologie de conception mise en place a été appliqué sur trois cas d’études correspondant à des applications cibles : haute tension, moyenne tension et ferroviaire. Les résultats obtenus montrent effectivement la performance et la nécessité de cette approche

The increasing complexity of power electronic devices requires the intervention of computer-aided design in electrical engineering. Development of electric/electronic systems nowadays is carried out by the help of virtual prototyping, in which simulation software are used to predict components behavior without investing time and money to build physical prototypes. The increasing demand of low power, high efficiency devices forced designers to precisely analyze losses in each component constituting the system. Magnetic components constitute a major part of electronics devices. Therefore accurate modeling of magnetic materials is mandatory in order to predict their realistic behavior under variable operating conditions. Our work takes place in this context by proposing a non-linear dynamic model of magnetic components for use in circuit simulators. It includes the material nonlinear hysteretic and dynamic behaviors with accurate modeling of winding and core losses in addition to thermal effects that are not taken into account by existing models. The model is based on the principle of separation of static and dynamic contributions as well as Bertotti’s theory. VHDL-AMS is used as a modeling language due to its multi-domain modeling feature, allowing coupling with a thermal model. The magnetic component model is implemented in circuit simulation software “Simplorer” It is then tested in a widely used power converter application, the buck converter, to ensure non conventional excitation. The model is validated for different core inductors, different current ripples, different loads, different temperatures and a wide frequency range, La complexité croissante des dispositifs en électronique de puissance nécessite l'intervention de la conception assistée par ordinateur. Le développement de systèmes électriques/électroniques est effectué à l'aide du prototypage virtuel dans lequel les logiciels de simulation sont utilisés pour prédire le comportement des composants. De ce fait, le prototypage virtuel permet une économie de temps et d'argent pour la réalisation de prototypes. La demande croissante d'appareils à faible puissance et à haut rendement a obligé les concepteurs à analyser précisément les pertes de chaque composant constituant du système. Les composants magnétiques constituent une partie importante des appareils en électronique, par conséquent la modélisation précise des matériaux magnétiques est nécessaire afin de prédire leur comportement réaliste dans des conditions de fonctionnement variables selon l'application. Notre travail s'inscrit dans ce contexte et propose un modèle dynamique non linéaire de composants magnétiques pour une utilisation dans des simulateurs de circuits électriques. Ce modèle de composant magnétique inclut le comportement d'hystérésis non linéaire du matériau et permet une modélisation précise des pertes fer et des pertes joule avec de plus la prise en considération des effets thermiques qui, généralement, ne sont pas pris en compte par les modèles existants. Le modèle est basé sur le principe de la séparation des contributions statiques et dynamiques des pertes fer et s'appuie sur la théorie de Bertotti. Le langage de programmation VHDL-AMS est utilisé en raison de sa fonctionnalité de modélisation multidomaines, permettant un couplage avec un modèle thermique. Le modèle de composant magnétique est mis en oeuvre dans le logiciel de simulation de circuit "Simplorer". Il est ensuite testé dans une application de convertisseur de puissance, le convertisseur abaisseur qui permet de fournir une excitation non-conventionnelle. Le modèle est validé pour différents noyaux d'inductances, différentes ondulations de courant et niveaux de charge, différentes températures et une large gamme de fréquence

A major challenge in the aviation industry is to design and develop “more” electric aircraft. Indeed, the main systems use different types of energy such as hydraulic or pneumatic energy. The current trend is to convert these systems to electric power because it has many advantages and would allow economies of mass, energy and maintenance costs. With the increasing electrical systems in the aircraft, arise problems of interference and electromagnetic compatibility between these systems. Moreover, these power systems are subjected to severe working conditions, including extreme temperatures. As part of the FEMINA project (Filtrage Electromagnétiques et Matériaux pour l‟INtégration en Aéronautique), the goal of our team was to study an EMC filter subjected to extreme temperature conditions. This filter is composed of passive elements (capacitors and inductors) and designed to remove interference caused by electrical converter located close to the source of energy and heat (the propeller). As part of my thesis work, I focused on the effect of temperature on the behavior of inductors through the magnetic materials that compose them. I have thus determined the magnetic materials that I felt able to fulfill their role at high temperatures, then I developed a dynamic model of magnetic behavior, taking into account the skin effect and the effect of temperature and finally I tested this new model by including it in a circuit simulator to model a common mode filter that meets the specifications of our industrial partners., Un enjeu majeur de l’industrie aéronautique de demain est de concevoir et développer un avion « plus » électrique. En effet, sur un avion de ligne, les principaux systèmes utilisent des types d'énergies différents tels que l'énergie hydraulique ou pneumatique. La tendance actuelle est à la conversion de ces systèmes à l'énergie électrique car elle présente de nombreux avantages et permettrait des économies de masse, d’énergie, et de coûts de maintenance. Avec l’augmentation croissante des systèmes électriques dans l’avion se posent par conséquent des problèmes d’interférences et de compatibilité électromagnétique entre ces différents dispositifs. Par ailleurs ces systèmes électriques sont soumis à des conditions de travail très sévères, notamment des températures extrêmes. Dans le cadre du projet FEMINA (Filtrage Electromagnétiques et Matériaux pour l’INtégration en Aéronautique), l’objectif de notre équipe était d’étudier un filtre électrique soumis à des conditions de températures extrêmes. Ce filtre composé d’éléments passifs (condensateurs et inductances) est destiné à éliminer les interférences provoquées par le convertisseur électrique placé à proximité de la source d’énergie et de chaleur (le propulseur). Dans le cadre de mes travaux de thèse, je me suis intéressé plus particulièrement à l’effet de la température sur le comportement des inductances au travers des matériaux magnétiques qui les composent. J’ai ainsi déterminé les matériaux magnétiques que j’estimais capable de remplir leur rôle de filtrage en hautes températures, puis j’ai élaboré un modèle de comportement magnétique dynamique, tenant compte de l’effet de peau et de l’effet de la température et enfin j’ai testé ce nouveau modèle en l’incluant dans un simulateur circuit, afin de modéliser un filtre de mode commun répondant au cahier des charges de nos partenaires industriels.

Nowadays, numerical modeling is an indispensable tool for the prototyping of electromagnetic converters. Magnetic materials play an essential role into the energy conversion so it is necessary to control their behavior as well as their modeling. The objective of this work is to develop realistic laws of material behavior for circuit simulators use. Regarding the static behavior, the Jiles-Atherton model has been implemented and adapted, simplified and modified to improve accuracy and implementation. Dynamic modeling of the material was performed using the model DWM developed into the Ampere laboratory. This model incorporates the excedentary dynamic effects thanks to a "dynamical material law" implemented into the magnetic diffusion equation. Then this model was homogenized to improve its future implementation in a circuit simulator. Each of the different models has been tested and validated on several samples., De nos jours, la modélisation numérique constitue un outil indispensable pour le prototypage de convertisseurs électromagnétiques. Les matériaux magnétiques jouent un rôle essentiel dans la conversion de l’énergie, il est donc nécessaire de maîtriser leur comportement et leur représentation. L’objectif de ce travail s’inscrit dans ce cadre et s’attache à élaborer des lois réalistes de comportement de matériaux afin de les inclure dans des simulateurs de circuits. Concernant le comportement statique, le modèle de Jiles-Atherton a été implémenté puis adapté, simplifié et modifié afin d’en améliorer la précision et l’implémentation. La modélisation dynamique du matériau a été effectuée grâce au modèle DWM élaboré au laboratoire Ampère. Ce modèle intègre les effets dynamiques excédentaires grâce à une loi « dynamique de matériau » implémentée au sein de l’équation de diffusion magnétique. Ce modèle a été ensuite homogénéisé afin d’en améliorer son implémentation future dans un simulateur de circuit. Chacun des différents modèles a été testé et validé sur plusieurs échantillons.