High Temperature, High Frequency SiC Three Phase Inverter for Aircraft Applications 2010-01-1798
This paper presents the results of a silicon-carbide-based 300V
5 kW fully functional three-phase inverter module operating at high
temperatures and device junctions up to 200°C. Each phase power
module employs eight SemiSouth 100 mΩ/1200V SiC JFETs (SJEP120R100)
in parallel per switch position. The paper will highlight both the
electrical and the thermo-mechanical design. Experimental results
validating the overall design will also be discussed.
The core of the electrical design was to take advantage of the
low input capacitance, high switching frequency (50 kHz) and high
temperature capability of the SiC JFET in order to obtain a high
power density inverter. Since SemiSouth's SiC JFET is a
relatively new device, computer models are not currently available
from the manufacturer, which presents a hurdle during the design
stage. In order to produce reliable performance predictions, the
team has focused on developing a model for the SiC JFETs ultimately
used. This paper will cover some of the strategies used to
implement a first degree approximation model for the SiC devices.
Since enhancement-mode SiC power JFETs (such as the ones used in
the prototype) have a gate behavior different from that of
traditional MOSFET-type devices, this paper will also present the
gate driver strategy and ultimate gate driver hardware prototype
developed to properly drive the enhancement mode SiC JFETs.
Packaging topics covered include material selection, high
temperature processing issues, power substrate design, and system
thermal analysis. Concluding the paper are the high temperature
electrical test results of the prototype system.