Reliability driven virtual prototyping of power electronic equipment - a case study

This paper presents a method to implement reliability predictions at an early stage in the design process of power electronic equipment. Detailed information on the component losses are generated using circuit simulation tools. This loss map is applied in 3D thermal simulations of first layout proposals. With the resulting temperature distribution, a reliability prediction can be performed to identify critical components. This approach is studied with a 2.2 kW voltage source converter as example. The converter is cooled by natural convection only. Here, the DC link capacitors prove to be critical for the system lifetime. A simple geometric rearrangement of the capacitors already leads to a 60% increase in L10 lifetime, however at the cost of a decreased power density.