Characterization of 15 kV SiC n-IGBT and its application considerations for high power converters

Abstract

The 4H-SiC n-IGBT is a promising power semiconductor device for medium voltage power conversion. Currently, Cree has successfully built 15 kV n-IGBTs. These IGBTs are pivotal for the smart grid power conversion systems and medium voltage drives. The need for complex multi-level topologies or series connected devices can be eliminated, while achieving reduced power loss, by using the SiC IGBT. In this paper, characteristics of the 15 kV n-IGBT have been reported for the first time. The turn-on and turn-off transitions of the 15 kV, 20 A IGBT have been experimentally evaluated up to 11 kV. This is highest switching characterization voltage ever reported on a single power semiconductor device. The paper includes static characteristics up to 25 A (forward) and 12 kV (blocking). The dependency of the power loss with voltage, current and temperature are provided. In addition, the basic converter design considerations using this ultrahigh voltage IGBT for high power conversion applications are presented. Also, a comparative evaluation is reported with an IGBT with thicker field-stop buffer layer as a means to show flexibility in choosing the IGBT design parameters based on the power converter frequency and power rating specification. Finally, power loss comparison of the IGBTs and MOSFET is provided to consummate the results for a complete reference.