Gate-Driver Integrated Junction Temperature Estimation of SiC MOSFET Modules

SiC MOSFET power modules are becoming global solutions in systems operating in harsh environment, and due to large economic implications, achieving reliability of such systems is of utmost importance. Thereby, this article is focused on improving the reliability of the SiC MOSFETS, accomplished by generating intelligence on the gate driver (GD) with providing insight on real-time behavior of relevant switch information. The device switch current
$ {I_{\mathrm {d}}}$
, apart from being used for short-circuit detection assessing the short-term reliability, in the combination with the ON-state drain-to-source voltage
$ {V_{\mathrm {ds,\mathrm{\scriptscriptstyle ON}}}}$
enables the possibility of online junction temperature (
$ {T_{\mathrm {J}}}$
) estimation. The knowledge of
$ {T_{\mathrm {J}}}$
can enable active thermal control as well as condition monitoring of the SiC MOSFET device such as state-of-health, remaining useful life, and maintenance scheduling, tackling the long-term reliability aspects. With the aid of a field-programmable gate array (FPGA) on GD, a lookup table (stored in the FLASH memory on GD) containing device output characteristics is assessed, enabling real-time
$ {T_{\mathrm {J}}}$
monitoring for both devices in the commercial SiC MOSFET half-bridge module configuration. Following the developed GD prototype,
$ {T_{\mathrm {J}}}$
is verified in pulsed operation with maximum error less than 5 °C having excellent repeatability of ±1.2 °C and is furthermore verified in continuous operation showing promising results. In addition, degradation monitoring and aging compensation scheme are discussed, with the goal of maintaining the accuracy of the
$T_{\mathrm {j}}$
estimation throughout device’s lifetime.