Integrated Busbar Design for Stray Inductance and Volume Reduction in a High-Power SiC Traction Inverter

This paper presents a compact, partially laminated busbar design to connect the DC-link capacitor, high-voltage DC (HVDC) connector, and power module using a single integrated busbar. The proposed busbar design is designed for a high-power and high-voltage Silicon Carbide (SiC) traction inverter. The proposed solution eliminates the need for using separate busbars: one for the connection between the HVDC connector and the DC-link capacitor, and the other one between the connection of the DC-link capacitor and the power module. Incorporating two busbars in a single traction inverter increases the total volume of the inverter and the parasitic components. Thus, the main design goals in this paper are minimizing the parasitic inductances, increasing the power density, and achieving a uniform current distribution across the capacitor cores. Additionally, the compact busbar design allows a reduction in the parasitic resistance compared to two separate busbars and, hence, it reduces the power loss. The voltage overshoot and maximum allowable stray inductance of the busbar are investigated in detail. Current density and its effect on the busbar temperature rise are analyzed using 3D finite element analysis.