Efficient cooling of power electronics

Power electronics devices are generating heat losses up to several hundreds of Watt/cm². Chip shrinking causes a steady increase of heat to be dissipated. Intelligent solutions must be developed for better heat conduction from the chip to the ambient. The reduction of the thermal resistance of power modules is one of the challenges for the future. Decreasing the thermal resistance of the ceramic by use of thinner ceramics for the isolation substrates or ceramics with higher thermal conductivity is one alternative. Another possibility is direct liquid cooling of the isolation substrates either by using direct integration in a copper cooler system with micro-channels or by conventional soldering of the substrates to a liquid cooler with micro-channels. These solutions allow cooling with water temperatures up to 80degC so as not to exceed a chip temperature of 125degC. The usage of micro-channel copper structures improves the thermal resistance by 60% compared with a power module mounted onto a cold plate. Similar structured coolers are also used for cooling power laser diodes and processors.