ICIT - IEEE 2018

From 02/19/2018 to 02/22/2018

Centre de Congrès - Cité Internationale Lyon - 50, quai Charles de Gaulle 69463 Lyon


Tutorial 3 Dr Bernardo COGO

Title: Modern energy conversion with Wide BandGap devices: SiC and GaN haracterization forhigh performance converters.

Abstract:
With the recent development and availability of wide bandgap devices in the market, more and more power converters are being designed with such devices. Given their fast commutation, when compared to their equivalent Si-based counterparts, these new devices increase the converter’s efficiency and power density but they significantly affect Electromagnetic Interference and Partial Discharge issues on the systems connected to such converters. Anintroduction about issues on modern Power Electronics will bepresentedas well as the gain on using WBG technologies associated with innovative topologies. Following, a state of the art concerning the research, production and commercialization of GaN and SiC transistors is presented. We show that high-efficiency andhigh power density converterscan only be precisely designed if one can perform an accuratedynamic characterization of such fast transistors. Datasheetof these components not always containsthe data to precisely calculate switching losses. Moreover,classical measurementmethods can be very inaccurate when applied to such fast semiconductors. Thus, we presentand explain in detailsa more accurate characterization method. This method not only allowsus measuring switching losses of a WBG component integrated in its converter, but it also gives us information about switching speed and voltage overshoot during commutation. This information is very useful tocalculate filtering devices to reduce EMI issues and overvoltage on cables and loads connected to the converter. Results of switching energiesfor different SiC and GaN transistors will be presented, for different parameters which have a strong influence, such as: switching voltage and current, gate resistance,gate-source voltage, dead-time and temperature.Effects of such parameters on the switching speed and overshoot during the switching instants will also be shown.Adeep analysiswill be givenwith the purpose of understanding the relationship and trade-off between switchingenergy, speed and overshoot. Applications using these components is presented with focus on the work developed at the French Institute of Technology Saint-Exupery. Details on the impact of SiC components in apower drive system for More Electrical Aircraftswill be addressed as well as some solutions to reduce overvoltage and EMI filtering in this system, including control techniques developed based on the precise characterization results presented in this tutorial.