High speed IGBT module transient thermal response measurements for model validation

A test system is introduced and applied for validation of dynamic electro-thermal models of multichip insulated gate bipolar transistor (IGBT) modules. The test system operates the IGBT in a pulsed high power active mode with controlled current and voltage. The gate-cathode voltage is used as a time-dependent temperature sensitive parameter (TSP). The TSP is calibrated versus temperature with a temperature controlled test fixture using short pulses that do not result in self heating. It is shown that the temperature calibrations for the TSP must be performed on the same IGBT, and under the same conditions for which a transient measurement is to be made. Heating transient measurements are made for both multiple paralleled chips and for a single isolated chip in the same module. Comparisons between measurements of the single IGBT chip and paralleled chips indicate that current sharing is adequate for high-current, low-voltage heating conditions but is not adequate for high-voltage, low-current conditions. Model validation results indicate good performance of a previously developed IGBT electro-, thermal model for the range of heating rates tested.