Transient temperature measurements and modeling of IGBT's under short circuit

This paper discusses the estimation of possible device destructions inside converters in order to predict failures by mean of simulation, The study of insulated gate bipolar transistor (IGBT) thermal destruction under short circuit is investigated, An easy experimental method is presented to estimate the temperature decay in the device from the saturation current response at low gate-to-source voltage during cooling phase, A comparison with other classical experimental methods is given, Three one-dimensional (1-D) thermal models are also studied. The first one is a thermal equivalent circuit represented by series of resistance-capacitance (RC) cells, the second model treats the discretized heat-diffusion equation (HDE), and the third model is an analytical model developed by building an internal approximation (IA) of the heat-diffusion problem, It is shown that the critical temperature of the device just before destruction is larger than the intrinsic temperature, which is the temperature at which the semiconductor becomes intrinsic. The estimated critical temperature is above 1050 It, so it is much higher than the intrinsic temperature (similar to 550 K). The latter value is underestimated when multidimensional phenomena are not taken into account, The study Is completed by results showing the threshold voltage V-th and the saturation current I-sat degradation when the IGBT is submitted to a stress (repetitive short circuit).