What is the function of the laminated bus connecting IGBT and capacitor?

The bus bars are stacked to reduce the stray inductance of the line, thus reducing the turn-off overvoltage of IGBT (reducing L*di/dt).

The voltage and current level of IGBT used in traction field is high. In order to reduce the turn-off overvoltage of IGBT, laminated bus is used to reduce the stray inductance of the line, thus reducing the turn-off overvoltage.

The knowledge of specific laminated buses can be searched online.