Reliability Prediction for Inverters in Hybrid Electrical Vehicles

Due to the increasing importance of power electronic components in automobiles, it becomes necessary to consider their reliability. This applies especially to hybrid electrical vehicles (HEV) where a malfunction of the power electronics may prevent the vehicle to operate. Of paramount importance for the reliability of power electronics is the component operating temperature and temperature cycling. This paper deals with the development of an advanced simulation tool which is capable of determining the component temperature of a three-phase converter over long mission profiles. In addition, the expected converter reliability is calculated. To accomplish this, losses in the semiconductors and dc-link capacitors are determined first. Next, this loss data is fed into a thermal model to compute the component temperatures, for the whole mission profile.