An Efficient Approach Based on the Near-Field Technique to Solve EMI Problems: Application to an AC/DC Flyback Converter

Flyback converters have been widely used in low- and high-power applications because of their simplicity and low cost. However, they incur electromagnetic compatibility problems which are more difficult to control. The present chapter proposes an efficient modeling method based on the near-field technique to solve real-world radiation problems of the power electronics circuits. Firstly, for the characterization of an AC/DC flyback converter, several experimental measurements of the magnetic near field are performed in the time domain over the converter. Subsequently, we have applied the time domain electromagnetic inverse method based on the genetic algorithms on the measured signals to find the equivalent radiating sources of the studied circuit. The accuracy and the efficiency of the proposed approach have been demonstrated by the good agreement between cartographies of the near magnetic field components calculated using the developed model and those measured. Finally, the developed equivalent model has been used to predict cartographies of other components of the magnetic field which will be compared to measured cartographies. This confirms that the identified equivalent sources can represent real sources in the studied structure. The proposed method could be used for diagnosis and fault location in power electronics systems

THE DEVELOPMENT OF A REMOTE LABORATORY FOR INTERNET-BASED ENGINEERING EDUCATION

The development of feasible and cost-effective remote engineering and science laboratories is one of the most important problems facing the progress of online technical education. In this paper, we describe the development of a complete remote laboratory for the instruction of control engineering. Equipped with common industrial sensors and actuators, the system represents temperature and flow processes regulated with an industrial Programmable Logic Controller (PLC). Using local monitoring, we enable students to perform interactive real plant experimentation in control and automation without the overhead incurred in maintaining a full presence laboratory

Development of Generic Radiating Model for Rectangular Capacitors: Magnetic Near Fields Analysis and Modeling

This chapter deals with modeling the radiation from rectangular film capacitors as a power electronics component. The rectangular film capacitors are sources of electromagnetic radiation, where its characterization is crucial for electronic circuits EMC. Our study presents the analyses and modeling of the magnetic near field radiated by the plastic and the polyester capacitors. An electromagnetic inverse method is combined with an optimization method based on genetic algorithms to create a radiating equivalent model. A very good agreement is observed between the magnetic near field cartography measured above the studied structure and calculated using the developed model parameters. Finally, a generic radiating model is proposed for various types of rectangular film capacitors. The generic model is validated using the measurements on a rectangular capacitor. The obtained equivalent model can calculate the magnetic field at any near field zone and far field around the capacitors. Circuit designers can use the field distribution to optimize the placement of the capacitors on the printed circuit board to reduce their coupling and potential interaction with other equipment in the vicinity of the system

Modélisation du rayonnement électromagnétique des circuits d'électronique de puissance. Application à un hacheur.

The study of electromagnetic compatibility becomes an obligated passage for designers of power electronics circuits. The complexity of phenomena that come into action in that study makes more and more necessary the use of a CAD tool for prediction of radiated and conducted electromagnetic perturbations. The present work is devoted to modelling electromagnetic interference from power electronic circuits. The first proposed method is based on an analytic approach of the problem where the coupling in the circuit are approximately quantified. In the case of complicated circuit, these approximations are not sufficient, so the use of a numerical method becomes indispensable to take into account al1 the coupling in the circuit. The study of numerical methods shows that in the actual state of things, no-method is well adapted to Our application. Nevertheless, Our choice was fixed on the moments method which is the best when responding to specifications. While this method don't solve non-linear problems, it can not take into account non-linear components. So we propose its coupling with a temporal resolution to make linear the resolution. The method is implemented to solve problems with wire structures in three dimensions. After, it is applied to calculate interference from a circuit of a chopper. Numerical results are completed with an experimental evaluation of the radiated field. To improve numerical results, we investigate the “thin wire approximation” used when modelling printed circuit board (PCB). Finally, we propose a more accurate mode1 which take into account skin and nearby effects in the PCB.L'étude de la compatibilité électromagnétique (CEM) est devenue un passage obligé pour les concepteurs de circuits d'électronique de puissance. La complexité des phénomènes qui entrent en jeu lors de cette étude fait de plus en plus sentir le besoin d'un outil CAO de prédiction des perturbations électromagnétiques conduites et rayonnées. Le présent travail est consacré à la modélisation du rayonnement électromagnétique des circuits d'électronique de puissance. La première méthode proposée est basée sur une approche analytique du problème, où les couplages dans le circuit sont quantifiés de manière approximative. Dans le cas de circuits complexes, ces approximations ne sont plus suffisantes et il devient indispensable d'utiliser une méthode numérique afin de tenir compte de tous les couplages. L'état de l'art en matière de méthodes numériques nous montre qu'en l'état actuel des choses, aucune méthode n'est complètement adaptée à notre application. Néanmoins, notre choix s'est fixé sur la méthode des moments qui répond le plus à notre cahier des charges. Etant donnée que celle-ci ne résout pas les systèmes non linéaires, et sachant que notre résolution doit tenir compte de la présence de composants non linéaires, nous proposons un couplage avec un simulateur de circuits afin de linéariser notre problème. La méthode est mise en oeuvre pour permettre la résolution de problèmes avec structures filaires en trois dimensions. Ensuite, elle est appliquée pour calculer le rayonnement d'un circuit de type hacheur. Les résultats de calcul sont complétés par une évaluation expérimentale du rayonnement. Afin d'améliorer les résultats numériques, nous examinons la validité de l'hypothèse "fil fin" adoptée pour modéliser les pistes de circuits imprimés. Finalement, nous proposons une hypothèse plus précise qui permet de tenir compte de l'effet de peau et de l'effet de proximité dans les pistes

Evolution of Electrical Performance in First Generation of SiC MOSFET for Low Voltage Applications after Short-Circuit Aging Tests

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Effect of SiC MOSFET Terminal Capacitances Evolution after Short-Circuit Aging Tests on Conducted EMI in a Boost Converter

International audienceFirstly, this paper presents the effect of short-circuit aging test on the electrical characteristics of Silicon Carbide (SiC) MOSFET. Experimental test is detailed and the evolution of parasitic input, output, reverse transfer capacitances (Ciss, Coss and Crss) is presented. Moreover, three capacitances between terminals, drain-source, gate-source and gate-drain capacitances (Cds, Cgs and Cgd) are evaluated before and after repetitive short-circuit aging test. Secondly, in order to verify if the variation of these capacitances after aging can influence the Electromagnetic Interferences (EMI), we present a comparison of the EMI generated by a DC-DC boost converter before and after repetitive short-circuit aging test. Therefore, this work presents an experimental study of the short-circuit aging effect on the C-V characterization of SiC MOSFET to evaluate its electromagnetic behavior after degradation

Modélisation d'un capteur de courant dédié aux mesures en CEM et en électronique de puissance

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Shielding effectiveness of perforated screens through an inverse problem-based resolution,

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