Uh oh, now we're significantly increasing the loop area. The only reason for doing a laminated bus (like before) is to have small loop area. Increasing the loop area will increase voltage spikes at turn-off of the IGBT. The path from CAPACITOR PLUS to IGBT C1 to IGBT C2/E1 to IGBT E2 to CAPACITOR MINUS to CAPACITOR PLUS must have an AREA that's as small as possible.
dv/dt = strayInductance*di/dt
The di/dt will be very big. Like 400amp in a microsecond. So,
di/dt = 400,000,000. dv/dt is the turnoff spike and must be kept under, say, 100v (300v bus + 100v is 400v). We don't want to get near the 600v limit of the IGBT. So, stray inductance must be below:
100/400,000,000 = strayInductance
250nanoHenries = strayInductance
The laminated bus with that capacitor can have a stray inductance in the neighborhood of 5 nanoHenries.
This has the formula for inductance of a rectangular loop. I'm not sure what the area would be, but you could try to plug in the values, and see how many nanohenries you get out:
http://www.technick.net/public/code/...ance_rectangle