DRSSTC: IGBT selection

[matt0852]

Hi everyone,

Here are the calculated specs for my planned DRSSTC:
Secondary: 6cm dia, 18cm length, 1400 turns, AWG36, 296.45kHz
Primary: 12cm dia, 3cm length, 6 turns, AWG14, 245.15kHz (17% detuned)
Topload: 4.5cm minor dia, 18cm major dia
Tank cap: 0.068uF 3kV CDE
Coupling: 0.187

Originally I intended to use the famous FGA60N65SMD IGBTs in a halfbridge configuration. However, I found a similar IGBT with similar ratings: IGW75N65H5XKSA1 at a better price. Here's the datasheet: https://www.infineon.com/dgdl/Infineon-IGW75N65H5-DS-v02_02-EN.pdf?fileId=5546d4624d6fc3d5014df745d10c4394

So far I can't find anyone who has used this IGBT before for a DRSSTC, what do you all think of it?

[Mads Barnkob]

IGW75N65H5XKSA1 has a thermal resistance of 0.38 from junction to case, where FGA60N65SMD only has 0.25, so you need to put more effort into your cooling design with the IGW75N65H5XKSA1.

IGW75N65H5XKSA1 has a total switching loss of 3.2 mJ, where FGA60N65SMD has 1.99 mJ, so related to above, you have more to cool with a higher resistance, so the IGW75N65H5XKSA1 will run hotter.

IGW75N65H5XKSA1 has a gate charge of 160 nC, where FGA60N65SMD has 189, so you can switch on IGW75N65H5XKSA1 faster.

IGW75N65H5XKSA1 has a total switching time of 270 ns, where FGA60N65SMD has 220 ns, so you can not run the IGW75N65H5XKSA1 at a higher frequency than FGA60N65SMD.

This was just a quick comparison on some key specifications where it primarily deals with losses, because that the IGW75N65H5XKSA1 is rated for 300 Apulse vs. FGA60N65SMD 180 Apulse is not really useful if it can not dissipate the generated heat.

If you want to do a full calculation on maximum frequency in a soft switching/resonant inverter and also determine your limits from a maximum allowed temperature rise, you could use my guide on doing these calculations and estimations: http://kaizerpowerelectronics.dk/tesla-coils/drsstc-design-guide/igbts/

Please do ask if there is something in the guide that you do not understand, then I also have a chance to make the guide better

[matt0852]

Thanks for the details! Will probably stick to FGA60N65SMD since the price difference isn't that great anyway, and it is much more commonly used in the drsstc community.