RUL Estimation of IGBT Modules Under Power Cycling Stress

In this paper, a prognostics based methodology for estimation of Remaining Useful Life (RUL) of Insulated gate bipolar transistor (IGBT) is demonstrated. A failure analysis of IGBT module is performed to identify the dominant failure modes, mechanisms and stresses. Physics of failure (PoF) technique is applied to estimate its RUL. Modified Coffin-Manson model is chosen to obtain a relationship between cycles to failure and power cycling across junction of IGBT. Two accelerated life testing (ALT) experiments are planned and conducted to estimate the model parameters. During the experiments, junction temperature of IGBT module are monitored indirectly using temperature sensitive electrical parameter (TSEP) method. Failed IGBT modules are inspected using optical microscope and digital radiography system. The Rain Flow counting algorithm is employed to determine the number of cycles, while the Palmgren–Miner cumulative damage rule is employed to estimate the damage caused by these cycles. Finally, RUL estimation of IGBT modules is demonstrated under power cycling stress using sample power cycling stress data. This research work focuses only one parameter i.e. change in junction temperature. Effect of the multiple failure mechanism on IGBT module fatigue life can also be studied in the future.