TSEP-based junction-temperature estimation in half-bridge topology

Junction-temperature (Tj) monitoring of SiC MOSFETs using temperature-sensitive electrical parameters (TSEPs) is attractive for online health assessment, most calibrations are performed on a single device and neglect the interaction within a half-bridge leg. In particular, the drain current overshoot during upper-switch commutation has been proposed as a highly sensitive TSEP, yet the extent to which the complementary device junction temperature Tj, comp corrupts the Tj, DUT estimation remains unclear. This paper experimentally investigates the influence of upper-switch commutation on lower-switch TSEPs in a discrete 1200 V SiC half-bridge under double-pulse excitation. The results show that ID, peak exhibits the highest Tj, comp temperature sensitivity and yields a junction-temperature error below 3°C, These findings demonstrate that single-TSEP calibration can be severely biased in realistic half-bridge operation and highlight the need for multi-TSEP regression that explicitly accounts for bus voltage, load current and complementary device temperature when designing robust online Tj monitoring.