Calibration and Measurement of V ce - T j Correlation With Temperature Distribution of IGBT and Interconnections

Online junction temperature (Tj) estimation for power semiconductor device insulated gate bipolar transistor is of great importance for reliability assessment and enhancement. Typically,Tjcan be online calculated using the pre-calibrated correlation withon-state collector-emitter voltages (Vce) at loading current. However, the uneven temperature distribution inside the device during calibration is different from the conditions during operation. Uneven thermal distribution inside the device and self-heating of chips will cause significant estimation error by using the pre-calibratedTj-Vcecorrelation, as the voltage drop on interconnections will be different. In this article, a novel calibration method ofTj-Vcerelationship under pulsewdith modulation operation of device is proposed. By varying the switching frequency with fixed heatsink temperature, adjustable self-heating conditions and temperature distributions inside the device can be recreated. Moreover, a group of new relationships between junction temperature, heatsink temperature and temperature of interconnections inside device are revealed. By using the discovered relationship, the influence of uneven temperature distribution onVcecan be compensated in a noninvasive way, which can achieve higher accuracy inTjestimation compared to the conventional method.