Performance Evaluation of High-Power SiC MOSFET Modules in Comparison to Si IGBT Modules

摘要

The higher voltage blocking capability and faster switching speed of silicon-carbide (SiC)mosfets have the potential to replace Si insulated gate bipolar transistors (IGBTs) in medium-/low-voltage and high-power applications. In this paper, a state-of-the-art commercially available 325 A, 1700 V SiCmosfetmodule has been fully characterized under various load currents, bus voltages, and gate resistors to reveal their switching capability. Meanwhile, Si IGBT modules with similar power ratings are also tested under the same conditions. From the test results, several interesting points have been obtained: different to the Si IGBT module, the over-shoot current of the SiCmosfetmodule increases linearly with the increase of the load current and it has been explained by a model of the over-shoot current proposed in this paper; the induced negative gate voltage due to the complementary device turn-off(crosstalk effect) is more harmful to the SiCmosfetmodule than the induced positive gate voltage during turn-onwhen the gate off-voltage is –6 V; the maximumdv/dtanddi/dt(electromagnetic interference) during switching transients of the SiCmosfetmodule are close to those of the Si IGBT module when the gate resistance is larger than 8 Ω but the switching loss of the SiCmosfetmodule is much smaller; the switching losses of the Si IGBT module are greater than those of the SiCmosfetmodule even when the gate resistance of the former is reduced to zero. An accurate power loss model, which is suitable for a three-phase two-level converter based on SiCmosfetmodules considering the power loss of the parasitic capacitance, has been presented and verified in this paper. From the model, a 96.2% efficiency can be achieved at the switching frequency of 80 kHz and the power of 100 kW.