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The higher switching speed attainments of WBG power devices such as silicon carbide (SiC) MOSFETs, and their ability to operate at higher switching frequencies, becomes conflicting when challenged with electromagnetic interference (EMI) issues. The objective of this dissertation is to improve the design of pulse transformers integrated in an intermediate stage of a power converter system, known as a gate-driver. The main goal is to mitigate the parasitic capacitances of these transformers, which are the source originators of common mode (CM) currents. A modelling and simulation scheme of pulse transformers with alternative shielding structures has been developed. The transformer is primarily designed using Altium Designer while respecting IPC-2221 standards. Its geometry is then exported into ANSYS Q3D Extractor, where an equivalent circuit model is extracted. The correlation of the susceptibility of pulse transformers comprising different shielding structures is simulated by applying pulses of 1.4 kV amplitude, representing a dv/dt of 125 kV/μs, between the primary and secondary distinctive grounds. The influence of the shielding configuration, and the variation of its length, width and thickness is explored. In addition to the applied simulation analysis, an equivalent experimental examination was conducted after manufacturing the studied transformers. The correspondence of the simulation and experimental results permitted the validation of the models., L’accroissement de la vitesse de commutation des composants de puissance dits « grands gaps » tels que les MOSFETs à carbure de silicium (SiC) et leur capacité à fonctionner à une fréquence élevée ont amené de nouveaux défis à résoudre tels que les problèmes d'interférence électromagnétique (EMI). Les travaux de recherche présentés dans ce mémoire visent à améliorer le design des transformateurs d’impulsions intégrés dans les étages de commande rapprochée (nommé gatedriver). L’objectif visée était de limiter les capacités parasites de ces transformateurs qui sont à l’origine de courants de mode commun (CM). Une méthode permettant de concevoir et de simuler ces transformateurs d’impulsions avec différentes structures de blindage a été mise au point. Le transformateur est d’abord créé sous Altium Designer, tout en respectant la norme IPC-2221. Le design de ce transformateur est ensuite exporté vers ANSYS Q3D Extractor où un modèle électrique équivalent est extrait. En simulation, des impulsions d’amplitude 1,4 kV et présentant des dv/dt de 125 kV/μs ont été apppliquées entre le primaire et le secondaire des transformateur, ce qui a permis de comparer la susceptibilité du transformateur avec différentes structures de blindage. L'influence de la forme de l’écran, des variations de sa longueur, sa largeur et son épaisseur est étudié. En parallèle de la simulation, les transformateurs étudiés ont été fabriqués et soumis aux mêmes dv/dt qu’en simulation. La comparaison des résultats expérimentaux avec les simulations ont permis de valider les modèles.

Silicon Carbide (SiC) metal-oxide-semiconductor field-effect transistor (MOSFET) has a smaller short-circuit tolerance, and hence requires faster and more accurate short-circuit protection. One prospective method is to combine fast di/dt detection with an integration circuit. The former is for detecting the extremely fast increase of short-circuit current, while the latter is for generating a scaled copy of the short-circuit current for comparison with a threshold. The integration is almost always performed with a resistive-capacitive (RC) low-pass filter due to its simplicity. However, it does not produce consistent results under different load and fault conditions, which can, in turn, cause the detection to fail. An alternative di/dt-RCD (RC + diode) protective circuit has therefore been proposed to offer more accurate and consistent results, irrespective of the fault types. Design equations for the circuit have been derived for implementing an experimental setup, from which results have proven the effectiveness of the proposed di/dt-RCD protection.

Objective of this paper is to discuss the state of art IGBT Gate driver design, which includes the different isolation techniques, compatibility with power device and advanced protections feature. As the industry pushes for higher power and higher switching frequencies power supplies, which use IGBTs for power conversion. Reference to this, IGBT gate drivers is being designed to their ultimate attainable efficiency, smallest footprint, size and weight. Design and development of the Gate driver relates to the expertise on the circuit design and power devices operating characteristics. The subject is vital in order to adopt the modern design for critical operation (i.e., Traction, Healthcare, Energy).

National audience; Dans les convertisseurs de puissance, les circuitsde commande des composants de puissance, appelées ‘gatedrivers’,ont un rôle essentiel. De nos jours, ils intègrent de plus enplus de fonctionnalités telles que la détection du court-circuit debras, le blocage en douceur en cas de défaut, la surveillance de latension du composant de puissance à l'état passant… Des travauxde recherche sont en cours sur l'intégration de fonctions desurveillance en ligne pour une maintenance prédictive.L'instrumentation d’un gate-driver suppose l'intégration desystèmes de communication pour transmettre les données desurveillance. Dans les convertisseurs de fortes puissances, les gatedriversdoivent obligatoirement disposer d’une isolationgalvanique. La capacité parasite de la barrière d'isolation estcritique dans ces conceptions car elle peut conduire à la circulationde courants de mode commun pendant la commutation. L'ajoutd'optocoupleurs ou de transformateurs supplémentaires sur labarrière d'isolement est donc à éviter. Dans cet article, unenouvelle méthode de transmission bidirectionnelle de donnéesintégrée au gate-driver est détaillée. Le procédé décrit permet lamise en oeuvre d’alimentations isolées galvaniquement et unéchange bidirectionnel de données avec un unique transformateurd'alimentation. Des essais réalisés avec un convertisseur 400V-200A équipé montrent qu’il est possible d’atteindre des débits de1Mb/s pour TxD et 16kb/s pour RxD. L'applicati

International audience; In power electronics, gate-voltage measurement is used to optimize the design of the gate driver. Therefore a proper measurement technique is vital to ensure the proper operation of the electronic device. Measuring a small signal in a high switching voltage environment is a complicated task especially for high-side switches in a half-bridge configuration with fast semiconductor devices where voltage probes are subject to high common-mode voltages with fast transients. Hence, this article compares experimentally the conventional differential probes with optically isolated probes for measuring a small signal (26V) with a 1200V common-mode voltage and high switching rates created by SiC MOSFET (30kV/µs). The conventional differential probe shows differences of measured voltage amplitude up to 10V compared to optically isolated probe. The experimental results prove that parasitic elements of conventional differential probes change the gate-voltage shape and increase the common-mode current in the experimental setup up to 6dB.

Sklopovi učinske elektronike omogućavaju transformaciju napona i struja uz visoki stupanj iskoristivosti (u nekim slučajevima veći od 98 %). Glavni element svakog učinskog sklopa je poluvodička sklopa. Kako bi poluvodič radio kao sklopka potrebno je prikladno upravljanje poluvodičem. U ovom radu obrađene su osnovne metode upravljanja IGBT tranzistorom te je izrađen projekt okidnog sklopa za energetske module u EconoDual pakiranju. Tijekom projektiranja poštivani su projektni zahtjevi te je tiskana pločica crtana u skladu s međunarodnom normom. Na temelju izrađenog projekta napravljen je prvi prototip okidnog sklopa. Izrađeni okidni sklop je ispitan čime je utvrđeno da radi ispravno. Tijekom projektiranja okidnog sklopa napravljen je razvoj transformatora za DC-DC pretvarač s galvanskim odvajanjem. Power electronics circuits enable voltage and current transformation with a high degree of efficiency (in some cases greater than 98%). The main element of any power circuit is a semiconductor switch. Proper semiconductor control is required for the semiconductor to operate as a switch. In this paper, the method of IGBT transistor control is investigated and gate driver was designed for the energy module in EconoDual packaging. During the project, project requests were set and the printed circuit board was drawn in accordance with international standards. Based on the developed project, the prototype of gate driver was made. Gate driver was tested to determine if it was working properly. During the design of the gate driver, the development of a transformer for a DC-DC converter with galvanic separation was made.

Wide-bandgap (WBG) semiconductors, such as gallium nitride (GaN), are more and more being used in switching power devices. An AlGaN/GaN/AlGaN Double Heterojunction Field Effect transistor (DHFET) was developed in previous work and needed to be tested. The used test circuit was a buck converter. This type of converter, in addition with the normally-on switching behaviour of the GaN-based transistors, requires dedicated gate drive circuitry, resulting in the development of three types of gate-drivers. This paper presents the topology and performance of these drivers. Because of the type of converter, the drivers need to be galvanically isolated. Furthermore, because the experimental GaN transistors are normally-on, the drivers need to be robust so that they apply a negative gate-to-source voltage to switch off the transistor in case an error occurs in the driver. A third requirement for the drivers is that it has to be easy to adjust the voltage levels, in order to test the devices at different gate-to-source voltage conditions. A final requirement is that it has to be possible to construct the drivers with readily available electronic components. Because the drivers are galvanically isolated, there is a parasitic isolation capacitance in the DC-DC-converter of the drivers. This gives rise to a common-mode current which possibly can disturb the operation of the driver. The article also discusses this common-mode problem. ispartof: PROCEEDINGS OF 14TH INTERNATIONAL POWER ELECTRONICS AND MOTION CONTROL CONFERENCE (EPE-PEMC 2010) ispartof: International Power Electronics and Motion Control Conference (EPE-PEMC 2010) location:Ohrid, Macedonia date:6 Sep - 8 Sep 2010 status: published