A review on real time physical measurement techniques and their attempt to predict wear-out status of IGBT

Insulated Gate Bipolar Transistors (IGBTs) are key component in power converters. Reliability of power converters depend on wear-out process of power modules. A physical parameter such as the on-state collector-emitter voltage (V_ce) shows the status of degradation of the IGBT after a certain cycles of operation. However, the V_ce mainly shows the wear-out of bond wire lift-off and solder degradation. The V_ce is normally used to estimate the junction temperature in the module. The measurement of V_ce is sensitive to the converter power level and fluctuations in the surrounding temperature. In spite of difficulties in the measurement, the offline and online V_ce measurement topologies are implemented to study the reliability of the power converters. This paper presents a review in wear-out prediction methods of IGBT power modules and freewheeling diodes based on the real time V_ce measurement. The measurement quality and some practical issues of those measurement techniques are discussed. Furthermore, the paper proposes the requirements for the measurement and prognostic approach to determine wear-out status of power modules in field applications. The online V_ce measurement for a selected topology is also shown in the paper.