Solid State Tesla Coil Burning Mosfets

[Nissan20det]

well I get a decent signal at my gate. nothing that resembles the GDT primary.
so that sag is only shown at the output of driver chips/ GDT Primary

U have a 0.1uf, 1 uf and a 100uF low ESR capacitor near to each driver chip as well to cover the gamut of transient response and reservoir stacking?

I'm not sure what you meant by this. Right now I am re wrapping my GDT with less windings and a much thicker wire as the primary same Cat5e cable as secondary on GDT.

You were saying something may just do the trick, what where you talking about doing?

 

[Mosaic]

I don't understand....where is the sag? If there is no SAG at the IGBT gates then u don't have a problem with the switching.

 

[Mosaic]

Here is my 'pulse' driver and pulse board.
The off white colored gate drive comes off the smt MCP1407 driver, 8 pin IC, goes thru a pair of ferrite bea ds and then thru a couple paralleled SMT ceramic caps then splits thru 3, 5 ohm Gate damping (thru hole) resistors and then finally into the gate pads of the IRF3205 totaling over 400nC of gate charge.

 

[Mosaic]

BTW, Have a look at this:
https://richieburnett.co.uk/hfsstc.html

 

[DerStrom8]

Apparently Mosaic wants to take over this discussion. Guess I'm out then.

 

[Mosaic]

Apparently Mosaic wants to take over this discussion. Guess I'm out then.

Whatever gave you that impression?

 

[DerStrom8]

Whatever gave you that impression?

I was trying to keep it structured in such a way as to maintain a clear path forward, but when three people are talking back and forth it's impossible to keep on track. If you want to take over that's fine with me, I'm not complaining. I just can't maintain structure this way. Not to mention you keep repeating things I've already said.

 

[Nissan20det]

Ya anyway, I did beef up my GDT primary gauge from cat5e to 18 gauge, then changed my GDT winding ratio to 6-8.5. As well added solder to the gate output traces it didnt change my waveform but not by much. Im not sure if its good or bad.
GDT primary
At Gate


DerStorm8 Please continue I was just trying any suggestions, was here working on this all day, so was just trying stuff. Just so ur not confused

GDT is now 6-8.5 turns, 18gauge as primary cat5e as secondary.

Current circuit bellow/ Only added those 10uf caps to schematic, they where on my board already.

 

[Mosaic]

If the waveform is good at the gate then the transistor is happy.
Maybe what you're seeing at the primary of the GDT is ground loop interference on your scope probe.
Move the scope ground wire around and see if it changes the trace.

 

[Mosaic]

I was trying to keep it structured in such a way as to maintain a clear path forward, but when three people are talking back and forth it's impossible to keep on track. If you want to take over that's fine with me, I'm not complaining. I just can't maintain structure this way. Not to mention you keep repeating things I've already said.

Didn't realise a forum thread was limited to a 2 person conversation.

 

[Nissan20det]

Could a weak power supply cause the driver to heat up? My driver supply is a 12v 1 amp wall transformer, reads about 14.7vrms definitely reads high for it's sticker.. I tested my drivers current draw and it's never above .5/.6 amp usually. So I figured I was okay there. But since there 9 amp drivers I'm confused how there heating up when I can't even supply over 1 amp


Just another thought

 

[Nissan20det]

I didnt lose you did I Derstorm?

 

[Nissan20det]

Derstorm, Whats next?

 

[Mosaic]

This is interesting:
https://www.coilcraft.com/cst2020.cfm

 

[Nissan20det]

Yeah that's pretty sweet, is that very much they already made CT for input? With those be used for secondary feedback or primary feedback? I never really understood primary feedback, it seems quite a bit more difficult than using your secondary.