Design of a Current Converter for the Study of the UV Emission in DBD Excilamps

This paper presents the design of a current converter to supply a DBD exciplex lamp. The structure is implemented, based on a Boost converter. An analysis in the state plane is used, to determine the stability of the converter and the values of current and voltage during the discharge phase. An electrical model of the lamp is used to simulate the non measurable variables: the gas current and the gas conductance. Finally, the relationship between the gas current and the UV emission is presented

Alimentation électrique des dispositifs à décharge à barrière diélectrique (DBD)

L’utilisation d’une Décharge contrôlée par Barrière Diélectrique (DBD) permet d’obtenir un plasma froid à pression atmosphérique dont une des utilisations est le traitement de surface. Actuellement, de tels dispositifs sont alimentés par des sources de tension variable (amplitude, fréquence) : la décharge obtenue est le plus souvent filamentaire (défavorable à la qualité du traitement de surface), notamment lorsque l’on souhaite transmettre une puissance élevée. Des études récentes menées pour l’alimentation de lampes à excimères [1] ont montré l’intérêt de remplacer la source de tension par une source de courant, afin d’obtenir la décharge sur une plus grande plage de puissance et de fréquence, de disposer de degrés de liberté permettant le contrôle de la puissance transmise. Cet article est dédié à l’étude théorique et expérimentale d’une structure d’alimentation électrique de ce type

Behavioral model of gallium nitride normally ON power HEMT dedicated to inverter simulation and test of driving strategies

International audienceIn this paper, the authors present a behavioral model of a GaN normally ON HEMT. Forward and reverse conductions are modelized. The modelling of both conduction modes is required to provide accurate diode-less synchronous switching-cell simulation. A dedicated transistor capacitance extraction procedure based on an analysis of turn-on and turn-off waveforms is also proposed and experimented

Robustness study of a fast protection method based on the gate-charge dedicated for SiC MOSFETs power device

International audienceThis paper focuses on the extensive robustness validation of a gate charge detection method designed for SiC MOSFETs under short-circuit operation, and, in terms of failure-modes. The benefits of having a fast (submicrosecond-150ns) detection method is illustrated by a 1D thermo-metallurgical simulation. This method is integrated owing to an optimized SMD/PCB technology (Surface-Mount Device/ Printed Circuit Board)

Comparison of IGBT short-circuit failure “ohmic mode”: Epoxy molded package versus silicone gel module for new fail-safe and interruptible power converters

International audienceAn epoxy molded package is compared with a silicone gel module with IGBTs chips in short-circuit failure modes with respect to critical energy, I2Tmelting and explosion energy capabilities. Special importance was attached to “ohmic mode” assessment and ageing of the failed chips. The molded technology yields a very low and stable Rsc (1000 h) also exhibit an acceptable drift of the Rsc property (sc value due to damage of the “free moving” wire-bonding on the chips. The authors show that the paralleled wires connections and the multiple parallel melting pits allow a sort of active redundancy and a possible on-state operation. All these results are used for the design of new and original failsafe converters. These topologies use only one paralleled safety leg that is spontaneously and directly connected in series with the failed devices, through the low Rsc value of the failed chips, without any additional complexity or extra cost

DBD lamp converter design using an electrical model of the load

International audienc

Switching Optimization of WBG Power Devices on Inverter Leg

International audienceIn this paper the authors are interested by the switching optimisation of a SiC Power MOSFET in an inverter leg. The authors explain their efforts to build a test-bench that allows the extremely fast switching measurement of this WBG (Wide Band-Gap) component. Then trade-off curves between the dv/dt versus the switching energy are presented. The parameters are the external gate resistor and an additional gate-drain capacitor. Finally, basic dv/dt models are proposed and compared with the experimental results

Full SiC multilevel chopper for three-wire supply systems in DC electric railways

International audienceCurrently, former DC supply systems reach their limits. In several European Railway networks, there are several sectors where it is not possible to operate locomotives at their nominal ratings or to increase traffic. Indeed, the line-voltage drops between substations leads to severe limitations. To improve the power capacity of the line, a three-wire supply system with voltage boosters based on Imbricated Cells Multilevel Chopper (ICMC) was proposed. At first, the principle of the three-wire supply system is recalled. Experimental results, performed on a test platform of the French railways, are then presented in the case of a double 1.5 kV supply system, with a three-level chopper based on 3.3 kV Si-IGBT modules. In order to increase system performance, the authors evaluate the interest of new SiC-MOSFET modules on this ICMC structure. An experimental test-bench is build with 1700 V/300 A SiC-MOSFET Half-Bridge Modules (SiC-MOSFET HBMs). The reactive components forming this converter, such as the flying-capacitors, are dimensioned and a design is selected in order to respond to constraints of high switching speed. A particular control is tested and is used to regulate all flying capacitors, while also operate at high switching frequencies (up to 50 kHz). The characteristics of this DC/DC converter are calculated, plotted, and compared to the same structure with 1700 V / 300 A Si-IGBT Modules

MVDC Three-Wire Supply Systems for Electric Railways: Design and Test of a Full SiC Multilevel Chopper

International audienc