Integrated Busbar Design for Stray Inductance and Volume Reduction in High-Power 3-Phase Traction Inverters Based on SiC MOSFET Power Module

This paper presents a compact, partially laminated busbar design to connect the DC-link capacitor, high-voltage DC (HVDC) connector, and power module by using a single busbar. The proposed busbar design is designed for a high-power and high-voltage SiC traction inverter. Generally, two busbars are used in traction inverters that use power modules. The first busbar is used to connect the HVDC connector and the DC-link capacitor, and the second busbar is used to connect the power module and the DC-link capacitor. Incorporating two busbars in a single inverter increases the total volume of the inverter and the parasitic parameters. Thus, the main design goals are minimizing parasitic inductances, increasing the power density, and distributing the current across the capacitor cores uniformly. Additionally, the compact busbar design allows the reduction in the parasitic resistance compared to two separate busbars and, hence, it reduces the power loss. Moreover, the busbar is made from bending a single sheet of copper to reduce the material and labor cost. Voltage overshoot and maximum allowable stray inductance of the busbar are investigated in detail. Current density and its effect on busbar temperature rise are analyzed using 3D finite element analysis (FEA) models.