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Behavioral EMI-Models of Switched Power ConvertersBishnoi, Hemant 05 November 2013 (has links)
Measurement-based behavioral electromagnetic interference (EMI) models have been shown earlier to accurately capture the EMI behavior of switched power converters. These models are compact, linear, and run in frequency domain, enabling faster and more stable simulations compared to the detailed lumped circuit models. So far, the behavioral EMI modeling techniques are developed and applied to the converter's input side only. The resulting models are therefore referred to as "terminated EMI models". Under the condition that the output side of the converter remains fixed, these models can predict the input side EMI for any change in the impedance of the input side network. However, any change at the output side would require re-extraction of the behavioral model. Thus the terminated EMI models are incapable of predicting the change in the input side EMI due to changes at the output side of the converter or vice versa.
The above mentioned limitation has been overcome by an "un-terminated EMI model" proposed in this dissertation. Un-terminated EMI models are developed here to predict both the common-mode (CM) and the differential (DM) noise currents at the input and the output sides of a motor-drive system. The modeling procedure itself has been simplified and now requires fewer measurements and results in less noise in the identified model parameters. Both CM and DM models are then combined to predict the total noise in the motor drive system. All models are validated by experiments and their limitations identified.
A significant portion of this dissertation is then devoted to the application of behavioral EMI models in the design of EMI filters. Comprehensive design procedures are developed for both DM and CM filters in a motor-drive system. The filters designed using the proposed methods are experimentally shown to satisfy the DO-160 conducted emissions standards.
The dissertation ends with a summary of contributions, limitations, and some future research directions. / Ph. D.
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Electromagnetic Interference Mitigation in Switched Mode Power Converters Using Digital Sampling TechniquesHAMZA, DJILALI 08 November 2011 (has links)
Increasing power density of switch mode power supplies, by increasing their switching frequency has becoming a challenging obstacle for EMI mitigation. The passive EMI suppression technique has always been the primary solution to fulfill the EMC requirement in terms of conducted emission limits. However, the call for stringent power supplies specifications renders the passive techniques less desirable, due to their increasing size and power losses. In other words, the greater the power density of the converter, the bigger the passive filter. Other suppression techniques such as the spread spectrum frequency modulation (SSFM), and soft switching, prove to have less performance and much complex to implement. The active analog EMI filters provide the basic noise suppression technique; however, their performance is dramatically impeded at higher frequency. This solution requires an additional small size passive filter to complete the EMC spectrum for conducted emissions.
Digital active filtering techniques offer advantages of flexibility, fewer external components and reduced overall size and power losses as compared to conventional passive filtering techniques.
In this thesis DSP-based and FPGA-based EMI control techniques to mitigate the conducted emissions of switch mode power converters are proposed. These techniques are implemented in-lieu of the passive filtering techniques, by keeping equal or better performance. Moreover, these solutions can be configured as a stand-alone or integrated into the converter digital controller algorithm.
Finally, the proposed solutions are implemented into three types of power converters, namely, a AC-DC power factor corrected converter, DC-AC micro-inverter for Photovoltaic application, and DC-DC for Electric Vehicle (EV) battery charger. Analytical, simulation and experimental results are provided to verify the proposed solutions. / Thesis (Ph.D, Electrical & Computer Engineering) -- Queen's University, 2011-11-07 10:48:49.191
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Modélisation du rayonnement électromagnétique quasi-statique des composants magnétiques de puissance - Application à la compatibilité EM - / Modeling of quasi-static electromagnetic field radiated by magnetic components used in EMI filtersLévy, Pierre-Etienne 08 June 2015 (has links)
L'augmentation du nombre de fonctions électriques disponibles dans les systèmes embarqués amène de nouvelles contraintes d'encombrement et de masse de leurs alimentations. Pour adresser ces problèmes, la miniaturisation et l'intégration des convertisseurs statiques sont donc des thématiques importantes de recherche qui aboutissent à de nombreuses évolutions technologiques et structurelles dont l'apparition de convertisseurs statiques à fréquence de fonctionnement élevée permettant la réduction des éléments passifs du convertisseurs.Ces avancées s'accompagnent cependant d'une augmentation des niveaux de perturbations électromagnétiques générés par le système. Afin de les diminuer, l'insertion de filtres CEM dans le système est nécessaire. Leurs performances sont fortement liées au contrôle de leurs éléments parasites. Les modèles développés jusqu'à présent concernent pour la plupart les effets conduits et l'évaluation de l'impact des phénomènes rayonnés est souvent ignoré ou au mieux basé sur des modèles simplistes. Un des objectifs de cette thèse est donc d'apporter un degré de complexification plus élevé des modèles de rayonnement des composants magnétiques utilisés dans les filtres CEM, tant par une approche par modélisation numérique que par la mise en oeuvre d'un modèle analytique.Dans un premier temps, une étude poussée du rayonnement magnétique de composants simples, les inductances toriques de mode différentiel, a été réalisée. Cette étude a débouché sur la mise en évidence des paramètres critiques déterminant la topologie du champ magnétique rayonné dans l'environnement proche du composant. Le résultat majeur de cette étude est l'importance de la répartition du bobinage autour du circuit magnétique sur le champ magnétique rayonné. De nouveaux modèles ont été proposés pour permettre la prédiction des champs proches rayonnés pour une gamme de fréquence inférieure à la résonance propre du composant.Par la suite, un modèle analytique fin du rayonnement magnétique des inductances de mode commun a été proposé. Ce modèle permet de déterminer \emph{a priori} le rayonnement magnétique proche du composant. Les études menées par la suite ont permis de relier les effets observés en rayonné au phénomènes conduits qui apparaissent dans ces composants notamment pour expliquer certains effets de transfert de mode (commun/différentiel).Dans une dernière partie, une étude de ces composants en susceptibilité électromagnétique (EM) a été menée. Elle a permis de rendre compte de l'influence d'une onde incidente de champ magnétique sur les composants étudiés et de valider les modèles proposés via une approche basée sur la réciprocité EM: la direction privilégiée de rayonnement est aussi celle de couplage facile pour un champ magnétique externe. / The number of electronic devices in embedded systems is constantly increasing and their contribution to volume and weight is a major concern. In order to solve these issues, a large research effort is devoted to volume reduction and power converters' integration. This lead to constant technological evolution including the appearance of high frequency power electronic converters allowing the reduction of the volume of passive components.However, due to the increase of operating frequencies and the minimization of inter-components distances, the electromagnetic radiations generated by these systems become more important. In order to decrease this interference, EMI filters are often necessary. Their performances are often related to the value of parasitic elements in the filter which must therefore be controlled. Nonetheless most of the existing models focus on conducted electromagnetic interference (EMI) and the impact of radiated phenomena is often ignored or greatly simplified. This work will therefore focus on developing highly accurate radiation models for magnetic components commonly used in EMI filters using both numeric and analytic tools.First, the magnetic fields radiated by differential mode (MD) toroidal coils, which belong to the basic magnetic components, will be thoroughly studied. This study highlighted the critical parameters determining the near-field topology. The main result is the discovery of the impact of the winding's layout around the magnetic core on the radiated magnetic field. New models have been developed in order to predict the radiated near field.Then, an accurate analytic model of the the magnetic radiation of common-mode (CM) chokes has been developed. It allows the prediction of the magnetic near-field. The application of the model lead to the correlation between radiated phenomena and conducted effects existing in these components. The importance of the winding on CM to DM mode coupling has therefore been highlighted.Finally, the electromagnetic (EM) susceptibility of these components has been studied. This work describes the influence of an external magnetic field on the components and validates the radiation models developed using the principle of EM reciprocity. It has been shown that the easy directions are the same for both the radiated and the coupled phenomena.
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