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.

Medium voltage power converter design and demonstration using 15 kV SiC N-IGBTs

“…Based on the switching characterization results, it was found that the dv/dt of the SiC IGBTs is about 100 kV/μs, at the beginning of the turn-on transition [3]. Unlike the low side gate driver in the double-pulse circuit, the high side gate driver (in a buck converter or voltage source converter) is exposed to high voltage and high dv/dt making it vulnerable to injection of common-mode currents.…”

“…Table I shows comparison of the conduction and the turnoff switching loss at 10 kV, 25 o C of both 2 μm and 5 μm IGBTs. The detailed switching data at higher temperature, different currents are shown in [3], [8]. As the target application of SST requires switching frequency in several kilohertz, the 5 μm IGBT is favorable for this application as its turn-off energy loss is considerably lower with very nominal higher conduction loss than the 2 μm IGBT.…”

“…Over the past two years, several papers discussing different individual parts of this work have been reported. The switching characteristics of the 15 kV N-IGBTs with comparison of fieldstop buffer layer thicknesses of 2 μm and 5 μm have been reported in [3]. The design and validation of 11 kV, over 100 kV/μs dv/dt immunity gate driver for the SiC IGBT has been reported in [7].…”

4H-SiC 15kV n-IGBT physics-based sub-circuit model implemented in Simulink/Matlab

“…High voltage 4H-SiC n-IGBTs have been fabricated [1] and experimentally characterized [2], showing fast switching and low conduction loss. Although Silicon IGBT models have been developed [3], very few 4H-SiC IGBTs model were reported [4].…”

Loss Model and Efficiency Analysis of Tram Auxiliary Converter Based on a SiC Device

“…Therefore, with the advent of SiC technology, the MOSFET on-resistance also decreases, even at higher voltages. Recently, silicon carbide devices for very high voltage applications have been developed [12][13][14][15]. The switching frequency of the SiC MOSFET high-power converter is higher than those of silicon IGBTs, with its lower conduction losses, combined with its inherent low switching losses, which achieves the benefit of working with smaller filter components [16][17][18].…”