Calibration Method of Junction Temperature Measurement for Press-Pack IGBTs

Accurate junction temperature measurement is of great significance for the reliability assessment of power insulated-gate bipolar transistor (IGBT) devices. The V
_CE
(T) method is the most widely used junction temperature measurement method and is recommended by various test standards, the first step of which is the K factor calibration (i.e., calibration). As a new type of package structure, press-pack IGBT (PPI) has the characteristics of double-sided cooling, and the traditional calibration method has the problem of applicability and accuracy. Based on the structure of the PPIs, a double-sided heating calibration method is proposed in this article, requiring the same heating power on both sides. The transient thermal finite-element model is established to study the temperature distribution inside the device under double-sided heating and its variation with time. Finally, the effectiveness and accuracy of the method are verified by the designed experiment. The results show that under double-sided heating, the temperature inside the device is very uniform, and the junction temperature of the chip is the same as the case temperature in real time. Therefore, the junction temperature can be equivalent by measuring the case temperature, which meets the requirements of the calibration experiment.