DBC-Packaged Inverter Power Module for Integrated Motor-Inverter Design Used in 48 V Mild Hybrid Starter-Generator (MHSG) System

This paper presents an improved package design of an inverter power module specialized for the 48 V starter-generator used in 48 V mild hybrid vehicles. The inverter module, called the mild hybrid starter and generator (MHSG), is integrated with its motor for size/volume reduction. However, the integrated motor-inverter presents supplementary challenges, such as limited cooling capabilities, in addition to the challenges resulting from the elevated voltage of 48 V of the mild hybrid systems. The proposed MHSG power module addresses these challenges. Parallel-connected metal-oxide-semiconductor field-effect transistor (MOSFET) dies were solder-bonded onto a direct bonded copper (DBC) substrate, and three DBC substrates (providing six legs) were assembled in a custom housing mounted on a forced air cooler. Shunt resistors and surface-mount device components were also soldered onto the DBC …