Capacitance Variations and Gate Voltage Hysteresis Effects on the Turn-ON Switching Transients Modeling of High-Voltage SiC MOSFETs

In this article, we present a discrete and real-time capable dynamic behavioral model of the turn-
on
switching transition of high-voltage and high-current silicon carbide (SiC) metal-oxide-semiconductor field-effect transistor (
mosfet
) half-bridge power modules. The dynamic switching model utilizes the Shichman and Hodges equations using voltage-dependent nonlinear device capacitances and module electrical parameters to obtain an accurate dynamic model of the device switching transients. The key device states that gate–source voltage, drain current, and drain–source voltage are modeled. This article investigates the impact of correct device capacitance modeling with low
off
-state gate–source voltage values, impacting the device capacitances and causes gate-voltage hysteresis effects. It has been shown that the presented discrete-time dynamic switching model accurately describes the turn-
on
transient and the results highlight the importance of correct capacitance and threshold voltage characterization data. The modeling results are compared with experimental measurements conducted in a 3.3 kV/750 A SiC
mosfet
power module. The model exhibits an average accuracy of
${{\sim}} 4\%$
for turn-
on
energy and
${\sim} 1.3\%$
for the turn-
on
time compared with measurements. These models are valuable for rapid and cost effective design and validation of advanced gate-driver circuits and for determining key design and operating parameters, such as dead time, switching frequency, and switching losses.