My second DRSSTC

[erdal]

Hi Mads,
I could not record the video because I tried inside at the home. It's make very dangerous sparks i just took some photos. I plans to record test videos outdoors

[erdal]

Hi again 

Full power @ 700amps 325 volts in open air tests 
I am planing to changing IGBT’s CM200 to CM300, 600v to 1200v with voltage dublicate

[oneKone]

i don't know how i missed the original build but this is awesome! i love the simple ingenuity behind the ikea desk. it's truly an amazing looking coil   

[erdal]

THNX oneKone
Misson Impossible 700 amps OCD, 340 v bus voltage

When johnny comes marching back home

mmc capacitors fail after long tests 

My new mmc design. each 0.1 uf, 1200 volts, 8 ampers irms,  12 parallel 5 serial total 60 caps. 0.24 uf 6.000 volt 96 amper irms

[Mads Barnkob]

These capacitors are also less sturdy than the CDE 942C series or snubber MKP pulse capacitors, so failure on such a MMC is expected if it does not have a large overhead for voltage and current specification.

Your new MMC layout is problematic, the inner capacitors will not be able to radiate the heat from their losses, so they will heat up faster than the outer ring of caps and will fail before the others due to temperature changing their characteristics.

[Bambinz]

I agree, and then if the inner caps fail the other caps fail consequently (avalanche effect).

[erdal]

Hello All,
Not work!
I changed the MMC, bus voltage ok, driver ok, but nothing any sparks.
Fuse not blown, no any shortcut at IGBTs
what would be the reason?

[erdal]

Hello,
Now working one of IGBT is death. G to E is 155 ohm
I changed CM200DY-12NF to CM300DY-12NF. Can i increase 700 amps to 900 amps at OCD?
Thank you
Erdal







Spark to strike rail

[Mads Barnkob]

I still recommend that you do a Fmax2, switching loss calculation to make sure that the CM300 can withstand 900A at 100 kHz, it is a much higher frequency than CM300 is usually used at. I think the highest recorded I got on my page is 700A at 72 kHz by loneoceans.com

Good to see that you found the defective IGBT brick, how about the gate resistor/zener diode, were they damaged aswell? I often saw this problem when a IGBT died.

[Hydron]

I see that you're using the 600V rated CM300, these should be a lot faster than the 1200V ones, so I suspect that 100kHz/900A will be ok, though at the upper limits of what you can do with them.