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 ( ${T}_{\text {j}}$ ) 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 ${T}_{\text {j}}$ estimation of IGBTs based on the initial turn-on voltage ( ${V}_{\mathrm {CE\_init}}$ ) is proposed in this article. In this method, the characterization behavior of ${V}_{\mathrm {CE\_init}}$ is thoroughly analyzed from the device and cell perspective. The current independence of ${V}_{\mathrm {CE\_init}}$ is evaluated with the help of the technology computer-aided design (TCAD). The theoretical definition and determination of the proposed ${V}_{\mathrm {CE\_init}}$ are then detailed. Moreover, the parameter dependence of ${V}_{\mathrm {CE\_init}}$ 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.