The main part of a static converter is the switch function. Insulated Gate Bipolar Transistors (IGBT) are now employed in most of medium power applications and their evolution is turned towards high power applications, such as railway traction. Because of the high power densities dissipated in these components, electrical and thermal pelformance of a power module is strongly linked. to its structure and its cooling system. This study deals with a process of integration in power electronics. The main goal is to improve compactness and reliability of power modules. After a presentation of the conventional structure of a module and the thermal concepts generally used in power electronics, we propose several solutions to reduce the thermal resistance of a module. First, an efficient heat sink was integrated in the module. The cooling principle is single-phase forced co~vection in microchannels. We propose a methodology to estimate the thermal resistance of multichip modules cooled with this type of heat sink. In ~ second stage, we propose a new technique of interconnexion for power devices, which allows to cool them on both sides. Then, a study of the substrates used in the modules is presented. In aIl cases, realisations and tests of prototypes allow to validate the model of the module and to show the feasibility of the proposed concepts.
