Tj-Vce Calibration under Self-heating Condition for Online Junction Temperature Monitoring of IGBT Module

Accurate temperature estimation is of great importance for the reliability of IGBT power modules. Junction temperature (Tj) can be online monitored using on-state collector-emitter voltage (Vce) at load current. However, the self-heating of the device under test (DUT) under relatively high current may cause errors when calibrating the Tj-Vce relationship. Moreover, the different voltage drops on the electrical connections due to nonhomogeneous temperature distribution under converter operation may cause more estimation errors. In this paper, a novel method of Tj-Vce calibration of IGBT modules utilizing the self-heating under large load current is proposed. Compared to the conventional method, the proposed one based on self-heating and low current injection is easy to be implemented, and is more suitable for the real converter operation, thus reducing the temperature estimation error.