Electrical method to measure the transient thermal impedance of insulated gate bipolar transistor module

The thermal characterisation of insulated gate bipolar transistor (IGBT) module is very important, since the production consistency and reliability are affected when IGBT is exploited in high temperature. To investigate the transient thermal behaviour of IGBT, a transient thermal impedance (Z_th) measurement system was built using the electrical method with gate-emitter voltage as temperature-sensitive parameter. Factors affecting the Z_th measurement, such as environment temperature, heating power, duty cycle and heating time, were discussed in detail. The Z_th of each component within IGBT module was measured by selecting right heating time before thermal equilibrium. It is found that the Z_th measurement has high accuracy and repeatability, which is helpful to understand how thermal performance of IGBT module varies with architecture and material properties for power electronic packaging.