Online computation of IGBT on-state resistance for off-shelf three-phase two-level power converter systems

Power converter systems in most of the applications are operated continuously with dynamically varying and highly inductive loads. The operating environmental conditions of the IGBT modules in such power converter systems is highly dependent on the thermal management. Hence, the operating conditions can be adverse when the system thermal management is not optimal. All this eventually triggers wear-out failures in the power modules. The on-state voltage and threshold voltage have been usually considered in the literature to investigate the device degradation in power modules. In this paper, a novel online computation method for the on-state resistance (rCE) of IGBT modules to develop the health monitoring model for power modules in off-shelf power converter system is proposed. The on-state resistance of power module is investigated so that it could be used as a potential precursor to identify aging of devices with solder die degradation as a failure mechanism.