Sensing IGBT junction temperature using gate drive output transient properties

Abstract

Insulated Gate Bipolar Transistor (IGBT) junction temperature sensing is normally achieved with a temperature detector. To optimize accuracy, the temperature detectors are placed very close to the power semiconductor chip or embedded on the power semiconductor die. This is inconvenient for power integration and requires further consideration for high voltage, high current, EMI protection, and the detector's thermal-mechanical stress. This paper presents a non-invasive method that integrates junction temperature sensing into the IGBT gate drive and enables high bandwidth sensing. In order to demonstrate the IGBT junction temperature sensing, an IGBT power module is implemented in an H-bridge, and driven by four push-pull type gate drives. The gate drive switching transient properties are used for IGBT junction temperature estimation. The “gate drive-IGBT” switching properties are modeled to explain the junction-temperature-dependent gate drive output dynamics. A hardware implementation for IGBT junction temperature extraction is provided. Experimental results are compared with circuit Spice model simulation.