Power module for Formula 1 with substrate water cooling
Main goals for a Formula 1 power module are highest power density and lowest weight. Volume and weight of presented converter could be reduced by roughly 50 percent compared to previous versions.
This AC-DC-converter for energy recovery, manufactured at Fraunhofer IZM, uses a direct substrate water cooling in order to minimize weight and volume and at the same time to provide a low thermal resistance due to a short thermal path. The surface of the substrate is enlarged by ribbons, which are ultrasonic bonded and reduce thermal resistance. The water duct is made of AlSiC for adapted CTE and the substrates are soldered into its openings. Eight SiC semiconductors in parallel for each switch ensure the required performance according to the KERS requirement; the module consists of three half bridges. To minimize stray inductance DC snubbers were mounted inside the module, eliminating the unfavorable inductance coming from the screw terminals. Housing is minimized as well by using only six small polymer fixtures, carrying the Cu terminals instead of one bulky housing.
Fraunhofer IZM co-designed the power module together with Magneti Marelli, developed the process sequence for prototype manufacturing and supported EDM by transferring the assembly process.