Thermal characterisation method for power transistors adapted to pool boiling cooling : Application to the characterisation of copper heatsinks, manufactured by 3D printing and sintering

As part of the energy transition, power electronics are facing a number of challenges to meet the sharp increase in electrical power transited. Large-gap semiconductor components enable higher power conversion, but also raise a number of electromagnetic and thermal problems within power modules. This thermal issue is leading to a redesign of power module packaging to reduce the thermal constraints on semiconductor chips and their assembly. With regard to this thermal management issue, the combination of a reduction in the number of interfaces between the semiconductor chip and the cooling fluid and an improvement in heat transfer allows to greatly reduce the thermal resistance of the power module.Therefore, the present work falls within this context of removing interfaces within the power module and improving heat transfers. The direct cooling of power semiconductors components without electrical insulator is then sought and pool boiling is chosen because of its better cooling performance for a passive heat transfer mode and its simpler implementation compared with a two-phase loop. The aim of these works is thus to develop a method to characterise the cooling of power transistors by pool boiling. An instrumented experimental bench was set up using HFE 7200 as working fluid and electrical insulator. A method for measuring the junction temperature of power transistor is used, based on a thermosensitive electrical parameter, the transistor control voltage. This measuring method is used to characterise the cooling in both static and dynamic regimes. This characterization method is applied to structured copper heatsinks manufactured by 3D printing and sintering.