A Current-Independent Junction Temperature Estimation Method for IGBTs Based on Initial Turn-on Voltage

The temperature-sensitive electrical parameter (TSEP) method is a widely accepted method to measure the junction temperature (Tj) of insulated gate bipolar transistors (IGBTs) noninvasively. However, the existing TSEP methods are typically limited by load current dependence, leading to inaccurate temperature information. To address this, a method for Tj estimation of IGBTs based on the initial turn-on voltage (V_{CE_init}) is proposed in this article. In this method, the characterization behavior of V_{CE_init} is thoroughly analyzed from the device and cell perspective. The current independence of V_{CE_init} is evaluated with the help of the technology computer-aided design (TCAD). The theoretical definition and determination of the proposed V_{CE_init} are then detailed. Moreover, the parameter dependence of V_{CE_init} is investigated with double-pulse tests (DPTs). Finally, the experimental validations are presented to demonstrate the effectiveness, accuracy, and high sensitivity of the proposed method based on a single-phase rectifier test bench.