Electro-Thermo-Mechanical Reliability Assessment of Arbitrary Power Electronics

Power electronics are key-enablers of several industry trends, such as more efficient renewable energy harvesting, eco-friendly mobility and many more. With their uprising use and versatility the requirement for these packages is steadily increasing; thus leading to an evermore complex electro-thermo-mechanical loading situation. On the one side, external loads such as vibrations or weather extremes leading to challenging thermal loading situations are present. On the other side, internal loads generated by the active semiconductor within a power package result in high temperature loads as well as high temperature gradients; promoting several failure modes caused by arising thermo-mechanical stresses. Consequently, the proper design of the thermal management of these devices plays a key role in their reliability. To this end, a multi-physics multi-domain approach is proposed to improve the operational reliability of power packages, by precisely describing the actual loading situation and assessing the resulting mechanical stresses. Thereby, in a global modeling approach entire PCB Assemblies (PCB-A) with actively loaded power packages can be examined electro-thermo-mechanically. Based upon the results of the global model areas of interest are identified, e.g. an area with high stress concentrations, and investigated further. To verify the developed methodologies an electro-thermal experimental test is used - a so-called Power Thermal Cycle (PTC) test. Using the proposed simulation strategy, critical areas can be determined. That allows the use of the tool for future virtual design optimizations of arbitrary power electronic systems, without the need of performing a time-consuming PTC test.