High power Insulated Gate Bipolar Transistors (IGBTs) are increasingly used in a wide range of safety and reliability critical applications e.g. transport and power generation. Historically IGBT/PEMs failed during thermal cycling at material interfaces. As IGBT performance demands increase with smaller size, higher current, voltage and switching rates so do the power density requirements of the Power electronic module (PEM). Power density is limited mainly by the max allowable semiconductor die temperature. Technology roadmaps point to increasing power density requirements. The thermal performance of the PEM is managed with heat sinks which increasingly incorporate liquid cooled systems. Existing heat sink solutions include cooled plates, microfins, micropin and micro-channel heat exchangers usually manufactured in Cu or Al. Thermal performance is directly linked to the specific surface area of the material which are fundamentally limited by the manufacturing processes. Metal foam heat exchangers are reported to significantly outperform microfin equivalents but are limited in application by the availability of effective, consistent low cost manufacturing processes.
The project will develop a low cost, high performance micro porous open cell aluminium
foam heat exchanger for IGBT cooling, will last 12 months and will develop the
manufacturing process for aluminium foam and the assembly processes to produce a
prototype IGBT cooler. To demonstrate its performance against the current cooling
configurations. Innovation will be required in order to ensure manufacturing consistency in
line with required parameters, specifically regarding uniformity of pore geometry & level of
porosity. Further innovation will be required in the assembly and joining processes to ensure thermal conductivity and reliability. The performance characteristics for the material will be developed to ensure that the cooler plates can be specified and scaled for specific end user requirements.