Online junction temperature extraction with turn-off delay time for high power IGBTs

High power insulated gate bipolar transistor (IGBT) modules are widely used in the wind power generator systems, electric locomotives, high voltage direct current transmission, etc. In such safety-critical and cost-sensitive applications, IGBT module reliability drawn research focuses. Research shows that IGBT reliability is closely related to junction temperature. In this paper, a junction temperature extraction method is presented based on device turn-off delay time. Module internal parasitic inductance is utilized to extract turn off delay time, and its temperature characteristics are analyzed. Experimental verification involves monitoring high power IGBT switching characteristics offline. The junction temperature extraction method based on turn-off delay time due to module parasitic inductance is viable and effective.