Thermal analysis of thermal spreaders used in power electronics cooling

Currently the thermal losses of power electronic devices like IGBTs are increasing. At the same time, their sizes are decreasing. Consequently heat sinks have to dissipate very large heat flux densities. Therefore the thermal environment is a main issue in their performance and reliability. In order to improve heat transfers, materials with high thermal conductivity seem very interesting. Because they are expensive, we propose to replace them with heat pipes. Firstly an experimental study is described in order to show the interests of heat pipes in power electronics cooling. Then thermal simulations on copper/water and silicon/water heat pipes are provided. Thanks to them, heat spreaders made with heat pipes and heat spreaders made with plain material are compared. A 40% decrease of the thermal resistance between the heat source and the ambient is expected.