Characterization of thermal interface materials for IGBT inverter applications

Power electronics applications require an accurate thermal management design. In this sense, one of the most important elements are thermal interface materials (TIMs) placed between the power devices and heatsinks in order to provide good thermal contact and (eventually) electrical isolation. To predict accurate thermal performances of the final assemblies, direct thermal tests are practically unavoidable, as the final thermal behaviour of TIMs depends on many parameters, such as mounting pressure, surface roughness, etc. and datasheets are often incomplete. Such thermal tests could be complex in final industrial systems and for this reason we propose a simple TIM evaluation setup for predicting the final thermal behaviour of IGBT-based inverters using such materials. The results obtained from two thermal pad TIMs and silicone grease are compared showing a good agreement with those obtained in test vehicles using functional IGBTs.