Reliability of High Temperature Inverters for HEV

The requirements for the reliability of electronic circuits becomes constantly higher. Therefore, in particular, the strongly growing automotive industry will be influenced, where the number of electronic circuits and the installed power is constantly increasing. Meanwhile for example a hybrid vehicle can be powered by an electrical system with more than 100 kW. The increasing power density of these circuits and the use of the components at higher ambient temperatures lead to the fact that the electronic components will heat up more and more. Additionally the further integration of electronic components requires a higher reliability of single semiconductors. With higher complexity it is more and more a challenge to prove the total reliability of these circuits by accelerated tests. Siemens has been working on the reliability of high temperature applications for years. This article describes a simulation concept, which calculates the crack propagation speed of bond and solder joint connections. Input parameters for the simulation are: Material properties, geometry and different stress types as current loads or temperature. This procedure is demonstrated on the basis of the power electronics for a hybrid drive system.