Low-Inductive HybridPACK(TM) HD Power Module for Future Proofen eTRUCK Inverters

Abstract:
This paper demonstrates the development of a mechanical design for a power semiconductor module for traction applications in electrified and future-proof heavy-duty eTRUCKS. Some fundamental differences in the requirements of eTRUCKS compared to passenger e-cars, such as 10x longer lifetimes, recurrent full-load cases, and higher vibration loads due to integrated electrical drivetrain architecture, are presented. We show how a low-inductive and mechanically robust connection concept can be implemented alongside the requirement for increased voltage levels future-proof insulation concept to support elevated voltages for MegaWattCharging (MCS) standards. The paper also shows how a power module as a half-bridge, with features such as alignment elements and preparation for integrated current measurement, can efficiently increase flexibility for an efficient integration into the drive inverter. The performance and cost-optimized development approach covered in this paper results in a power density appreciated for the eTRUCK traction inverter application, using state of the art SiC-MOSFET, that can only be achieved considering the required lifetime with efficient thermal management. Key parameters for this include high performance joint technology (HPJT), substrate design with thermally high conductive ceramic combined with high thermal spreading area in the material stack, and an improved pin-fin baseplate designed for flexible water flow direction combined with a low pressure drop to have an optimized heat transfer for direct water cooling.