Transistor choice

[flyingperson23]

I have 4 cm300ha-24h bricks and I was planning to make a big coil with them. I just stumbled upon the inverter module of a big ups which is based on 4 eupec 400ga 120dn2 bricks. Which bricks should I use?

[AstRii]

Looking at the datasheets, 400GA120DN2 bricks looks like they have slightly higher turn-off delay which will result in need for longer dead time. Since we ensure long deadtimes with Gate resistors, it will result in slower switching. On the other hand they seem to have much lower input/output and Miller capacitances which will result in easier drive and less voltage spikes. It's quite hard to tell which IGBTs will better suit your coil, especially when you haven't provided any further information about your coil. Will you use pulse-skipping driver? Are you aiming for lower or higher impedance primary?... etc. In general, since those IGBTs are not that much different, I would probably go with CM300 bricks as they are proven to work well in DRSSTCs by many people in this community.

It's also worth to note, that at this point when you wanna make big DRSSTC, you should be already able to tell what IGBTs to use. Maybe build something smaller before you use bricks, as building huge coils without much knowledge usually leads to destruction of IGBTs, wasted time, effort and money.

[Mads Barnkob]

As AstRii says, we need a lot more information to guide you properly.

To get an idea of what IGBT bricks can do what, check out the table of different DRSSTC builds in the bottom of this article: https://kaizerpowerelectronics.dk/tesla-coils/drsstc-design-guide/igbts/

[flyingperson23]

I was planning to do a much smaller coil but all the pieces for a bigger one fell into place. The ups inverter I'm building it around was built for 60hz it probably has a little higher than ideal inductance. My input power is a standard 240v 50a circuit so I'm aiming for somewhere in the 7-10kW range. I'm using a standard ud2.7, so no pulse skipping. Right now I'm heavily leaning towards the cm bricks because current won't be an issue and they're new and reliable.