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In this paper, a methodology is proposed for studying the current collapse effects of Gallium Nitride (GaN) power diodes and the consequences on the dynamic on-resistance (RON). Indeed, the growing interest of GaN based, high frequency power conversion requires an accurate characterization and a deep understanding of the device’s behaviour before any development of power converters. This study can ultimately be used to model observed trap effects and, thus, improve the equivalent electrical model. Using an in-house circuit and a specific experimental setup, a current-collapse phenomenon inherent to gallium nitride semiconductor is studied on planar 650 V—6 A GaN diodes by applying high voltage stresses over a wide range of temperatures. With this method, useful data on activation energy and capture cross section of electrical defects linked to dynamic RON are extracted. Finally, the origins of such defects are discussed and attributed to carbon-related defects.

Due to the high switching speed of Gallium Nitride (GaN) transistors, parasitic inductances have significant impacts on power losses and electromagnetic interferences (EMI) in GaN-based power converters. Thus, the proper design of high-frequency converters in a simulation tool requires accurate electromagnetic (EM) modeling of the commutation loops. This work proposes an EM modeling of the parasitic inductance of a GaN-based commutation cell on a printed circuit board (PCB) using Advanced Design System (ADS®) software. Two different PCB designs of the commutation loop, lateral (single-sided) and vertical (double-sided) are characterized in terms of parasitic inductance contribution. An experimental approach based on S-parameters, the Cold FET technique and a specific calibration procedure is developed to obtain reference values for comparison with the proposed models. First, lateral and vertical PCB loop inductances are extracted. Then, the whole commutation loop inductances including the packaging of the GaN transistors are determined by developing an EM model of the device’s internal parasitic. The switching waveforms of the GaN transistors in a 1 MHz DC/DC converter are given for the different commutation loop designs. Finally, a discussion is proposed on the presented results and the development of advanced tools for high-frequency GaN-based power electronics design.

This paper deals the design method of EMI filter associated with buck converter using silicon carbide (SiC) power semi-conductors. It's well known that to comply with EMC standards, EMI filters are necessary. The aim is to propose a design method based on an equivalent electrical circuit. Thus, the first step is the identification of the different elements of the proposed model but also the limits values of the parasitic elements of the passive components which play a major influence on the efficiency of the filters. The main objective is to study the influence of the common mode paths on the design of the filter before and after its installation. A filtering solution is proposed to reduce the high frequency disturbances caused by the fast SiC components. The simulation results obtained with the proposed model are compared with the measurements show the effectiveness of the proposed EMI filter design method.

The constant growth of electric consumption leads to considerable progress in power conversion. Recent studies have shown that using Gallium Nitride (GaN) as a technological building bloc permits to develop converter operating at high frequency with reduced volume and weight. Furthermore, it is conceivable the monolithic co-integration of devices towards full-GaN switching cells. Therefore, characterization of GaN power devices is needed to provide accurate models in a wide frequency band in order to design new generations of converters. An innovative modeling method for GaN High Electron Mobility Transistor (HEMT) power transistors based on the use of Scattering parameters (S-parameters) and small-signal equivalent circuit was recently developed and validated in previous studies. Meanwhile, the demand concerning GaN diodes increases, pushing forward the need for dedicated electric model. Through S-parameters, current-voltage and current-collapse measurements, this paper presents the characterization of packaged GaN diodes with the aim to establish an accurate nonlinear model. The analyzed devices are still in the development phase, but initial results are very promising and get close to commercial SiC diodes available on the market.

The embedded energy conversion systems onboard vehicles impose strong constraints on power density (low weight and volume) and robustness. Several solutions can be used to achieve these objectives which consist in acting either on the design of the static converter or on the electric machine. In this paper, we propose to act on the two systems together. Thus, the increase in the power density of the converter will be achieved by using wide band-gap semiconductor power devices like the SiC or GaN. These components are very small and able to operate at high frequency, thus reducing the dimensions of passive components and of the cooling system used. To increase the reliability of the electric machine, a multiphase PMSM is used. In this paper, the proposed design method of the integrated GaN inverter into a machine is presented. It will be used for the realization of an integrated GaN inverter into a multiphase PMSM.

— Currently, to increase the power density of static converters, it is necessary to increase the switching frequency to reduce the size of passive components. One of the solutions is to use wide-gap semiconductor components such as Silicon Carbide (SiC) or Gallium Nitride (GaN). Increasing switching frequencies causes significant voltage and current variations (dv/ dt) and (di/dt) that generate electromagnetic interference (EMI) over a wide frequency band. The subject of this paper is to study the design of an EMI filter for a DC-DC converter using a GaN transistor and SiC diode in order to reduce conducted emissions to comply with EMC standards. The EMI filter design method is based on an equivalent electrical model of the converter taking into account the impedances of the earth wire and the ground plane. A simulation based on the proposed model allowed to validate the design method by highlighting the solutions adopted to reduce noises spectrum at frequencies above 10MHz. Comparisons between the simulations results and the experimental data of conducted emissions with and without filters show the validity of the proposed method.

Power electronics converters require energy storage components. The DC-DC converters need the magnetic storage components which take a large volume. The new power GaN transistors allow to increase the operating frequency of the power converter. The consequence is a reduction of the values and the dimensions of the passive components mainly the inductors. In this paper, a design method for PCB-integrated inductors is proposed. It is based on the optimization approach of inductors volume. The inductor is integrated on PCB with a flexible ferrite sheets used as magnetic material.

This paper presents a design method of a power converter that will be used to realize integrated adjustable speed drives. In order to reduce the dimensions of the static converter to integrate it to the machine, a converter based on gallium nitride (GaN) transistor is being developed. Indeed, GaN transistors packages are small and can operate at high switching frequencies which lead to the reduction of the passive component dimensions. To design this GaN-converter, the determination of parasitical elements of the gate and power circuits is necessary. In fact, these elements have a direct influence on transient behaviour, on the transistor losses and therefore on the cooling system. This work is achieved within the project CE2I (Intelligent Integrated Energy Converter).

In this paper is presented the study of the influence of temperature on the attenuation of the electromagnetic interference (EMI) filters associated to the power converter used in the embedded system. It is well known that in the hybrid vehicle, the power conversion system can be located near the thermal engine where the temperature is very high. The consequence is that the performances of the passive components, like these used in the EMI filter can be affected. The aim of this paper is to study the influence of the external temperature on the electrical characteristics of the inductors and capacitors of the EMI filters used with DC-DC converter operating at 400 kHz. Firstly, each element of the filter is characterized separately to study the evolution of the different parameters with the temperature. Several capacitor technologies will be studied. Secondly, a high frequency models of the common mode (CM) and differential mode (DM) filters taking into account of the temperature influence are proposed. Finally, the filter model and the power converter impedance are used to study by simulation the influence of the temperature on the attenuation of the EMI filter. The obtained results have allowed make it possible to highlight the most influential elements on the filter attenuation.

It is well known that static converters are sources of conducted and radiated emissions. To reduce the conducted emissions towards the power network and meet with electromagnetic compatibility (EMC) standards (EN 55011), several solutions can be applied. The most used solution consists to install electromagnetic interferences (EMI) filter at the input side of the power converter. This paper deals with an EMI filter design method using the simulations at the design stage of the energy conversion system. In order to carry out these simulations, the accurate models based on high frequency equivalent electrical circuits are necessary. The aim of this study is to identify the different values of the filter models but also to obtain the limits values of the high frequency stray elements of the passive components which have a more important influence on the efficiency of the filters. One will also study the influence of the ground plane impedance on the performances of the filter in high frequency band. To valid the proposed method, the simulation results are compared to the measurements data without and with the EMI filter.

Since some years, one solution to increase the power density of the power converters consists to use the wide band gap semiconductors like SiC and GaN. These devices allow having power converters that operating with the high switching frequencies. These fast devices induce of very high variations of the voltage (dv/dt) and current (di/dt) during commutations. The direct consequence is the generation of the very high levels of the electromagnetic interferences (EMI) in a wide frequency band. This study is focus only on the conducted emissions induced by a Buck converter using GaN-transistor and SiC-diode. To reduce these emissions and to comply with EMC standards, one solution consists to use an EMI filter. In order to design the EMI filters by simulations, a modeling method based on an electrical equivalent circuit is proposed. This method allows taking into account of additional common mode impedance that correspond to the ground plane often neglected in the design of the filters. The comparison of the simulation results and measurements of the conducted emissions of the Buck-converter without and with the EMI filter confirm the validity of the proposed approach.

This paper deals the design of EMI filter associated with DC-DC converter using fast semiconductors as a silicon carbide SiC (diode and transistor JFET). The converter used in our study is a buck converter 200V, 2A operating at a switching frequency of 200kHz. To comply with EMC standards, a filter design method based on an electrical equivalent circuit model is proposed. Values of the various elements of the filter are obtained by simulation. The improvement provided by our model is important mainly in HF (above 1MHz) taking into account the impedances of the different propagation paths of the common mode currents of the converter. The comparison of the simulation results with the measurements data carried out on a converter without and with the EMI filter, shows the effectiveness of the proposed design approach.

The paper focuses on the design of EMI filter for a power converter used Silicon Carbide power devices (SiC-JFET and SiC diode). The DC-DC converter used in this study is a buck converter which has operating frequency of 100 kHz and the turn-on and turn-off times of the JFET are equal to ten nanoseconds. It is well known that the switching times have a direct link to the spectrum of the EMI sources. In order to reduce the conducted emissions induced by the SiC-converter, it’s necessary to add an EMI filter in order to compliance the EMC standard. In this paper, design method of the EMI filter based on the simulation is proposed. For this, a high frequency model of the filter which takes into account of all impedance paths of the system is used. Values of the various elements of this model are determined by a new approach. The improvement provided by this model is important in high frequencies (above 1 MHz) taking into account the measured impedances of different propagation paths of the common mode currents of the system. The conducted emissions measured without and with the obtained EMI filter show the effectiveness of the proposed design method.

Power semiconductor components with high switching speed are widely used in static converters. However, they pro-duce conducted electromagnetic interferences in high frequencies. Filters are one solution for reducing the conducted emissions. However, the parasitic elements of the passive components in the EMI filter deteriorate its performances. In this paper, we propose to study a differential mode (DM) inductor in planar technology. The goal is to reduce the parasitic capacitance of the planar DM inductor via an improved parasitic capacitance cancellation technique. The technique is based on the results of an analytical method using Electric Field Decomposition and energy based approach. The cancellation is then realized through the structural parasitic capacitances under an optimal geometry configuration. The efficiency of the proposed cancellation technique is validated by measurements.

The aim of this paper is to propose a new design method of EMI filters for the power converters using high frequency models of the passive components. It is well known that the static converters are the main source of conducted disturbances of the common mode and differential mode. Often, the solution used to reduce conducted emissions consists to use the EMI filters. The design of these filters is very difficult because it requires complete mastery of the design process. In this paper, a high frequency modeling method of the coupled inductors of filter is proposed. Coupled inductors and capacitor models are used to make a complete EMI filters. The high frequency models of these components are used in the simulations and the obtained results are compared to a prototype measurement data. A new EMI filters design method based on the optimization of the stray elements is detailed. It is based on the analysis of conducted EMI induce by the DC-DC converter.

Cet article traite du dimensionnement des filtres CEM utilisés pour les convertisseurs DC-DC. Les convertisseurs statiques utilisés dans les systèmes de conversion d’énergie génèrent d’importantes perturbations conduites de mode commun et de mode différentiel. Pour réduire ces perturbations et respecter ainsi les normes CEM en vigueur, il est nécessaire d’utiliser des filtres CEM. L’objectif de cet article est de proposer une méthode de dimensionnement des filtres CEM basée sur des mesures et des simulations. Les résultats de simulation du filtre proposé sont comparés aux résultats expérimentaux obtenus en utilisant un dispositif de mesure spécifique. Les résultats obtenus montrent une bonne concordance entre les courbes simulées et les relevés expérimentaux pour des fréquences variant de 150 kHz à 30 MHz.

The subject of this paper is the design of EMI filters for the DC-DC converters. It is well known that the static converters used in electric traction systems are major sources of conducted disturbances which are the common mode and differential mode. Often, the solution used to reduce conducted emissions consists to use the EMI filters. The design of these filters is very difficult because it requires complete mastery of the design process. In this paper, we propose a design method of the EMI filter based on the simulation of the filter in frequency domain. Thus, the high frequency models of the filter components are proposed. The obtained models have been tested and give good results on a large frequency range, from 9 kHz to 30 MHz.

Ce papier a pour objectif le dimensionnement d’un filtre CEM associé à un hacheur série utilisant des semi-conducteurs rapides au Carbure de Silicium SiC (diode et transistor JFET). Afin de respecter les normes CEM, une méthode de dimensionnement du filtre basée sur un modèle de type circuit électrique équivalent est proposée. Elle permet de déterminer les différentes valeurs des éléments du filtre à réaliser ainsi que les valeurs limites des éléments parasites des composants passifs à utiliser. Le dimensionnement du filtre est basé sur des simulations qui utilisent un modèle HF de l’ensemble du système de conversion d’énergie. Le but est d’étudier l’influence de la modification des chemins de propagation à cause de l’installation d’un filtre. Une solution est également proposée pour réduire les perturbations conduites qui apparaissent en haute fréquence provoquées par les commutations des composants SiC. Les mesures effectuées sur un convertisseur DC-DC, sans et avec filtre, montrent l’efficacité de la méthode de dimensionnement proposée.

Cet article présente une méthodologie de calcul de capacités parasites pour un composant magnétique de type planar en 3 dimensions. La méthode proposée est basée sur la décomposition du champ électrique entre plusieurs conducteurs (EFD). Des formulations 2D utilisées en micro-électronique ont été étendues pour pouvoir être utilisées dans le cas de composants magnétiques planar. Le calcul en 3D basé sur une approche énergétique, en tenant compte des effets du matériau magnétique, a été proposé. Des prototypes d’inductances et d’inductances couplées ont permis de valider cette approche analytique.

Ce papier traite du dimensionnement d’un filtre CEM associé à un hacheur série utilisant des composants rapides au Carbure de Silicium (SiC). Les perturbations conduites engendrées par le convertisseur en mode commun et de mode différentiel sont importantes et nous amènent à utiliser un filtre en double T pour réduire les perturbations dans une large bande de fréquence. De plus pour les fréquences supérieures à 10MHz un soin particulier a été apporté au blindage de l’ensemble convertisseur-charge afin de réduire au maximum les perturbations hautes fréquences et respecter ainsi la norme EN55011 (classe B). Une méthode de dimensionnement du filtre est proposée. Elle permet de déterminer les valeurs des différents éléments du filtre en tenant compte des éléments parasites des composants passifs qui réduisent ses performances. Les mesures des perturbations effectuées sur le convertisseur, sans filtre et avec le filtre, montrent l’efficacité du filtre réalisé. Mots-clés : dimensionnement des filtres CEM, filtre de mode commun, filtre de mode différentiel, modélisation des inductances couplées, perturbations conduites.

Depuis quelques années, les fréquences de fonctionnement des convertisseurs d’énergie ne cessent d’augmenter. Ceci est rendu possible grâce à l’utilisation des composants de puissance de plus en plus rapide. Ces composants modernes induisent de fortes variations de tension (dv/dt) et de courant (di/dt) durant les commutations. Ces fronts raides induisent des perturbations électromagnétiques conduites et rayonnées dans une large bande de fréquence. Dans le cadre de cette étude, nous nous intéressons uniquement aux perturbations rayonnées générées par un convertisseur DC-DC de type hacheur série. La structure étudiée est constituée de deux boucles localisées au niveau du circuit d’alimentation et du circuit de la charge. L’objectif est de mettre en évidence l’influence des topologies des deux boucles (du routage du circuit imprimé) sur le niveau du rayonnement électromagnétique.