Question about power supply output parasitics (scope shots attached)

[the_emi_guy]

Firstly, what is the switching frequency and what is the frequency of that ringing?

Salvador,
The first responder to your query asked about the frequency of the ringing. I don't think you provided this yet and its quite important info for debugging this.
There is no way to tell from your scope shots if we are dealing with KHz noise of MHz noise.

We can often use the ringing frequency as a way to figure out what is resonating. For example, if you suspect that the capacitance of the resonating tank circuit is a reversed biased diode, then you can put a small capacitor in parallel with the diode and see if it shifts the ringing frequency. This is a common method used to design snubbers.

 

[Salvador]

ok sorry for not telling that fully , it's just that I'm mostly doing everything myself including the thinking because I lost faith in this or any other internet forum for that mater long ago, also because nobodies responding etc.
the frequency fs the output ripple like pulses matches the turn on and off times of each IGBT, I saw this while measuring both the output and then the gate drive signal and it had this ringing , bigger at turn on less at turn off but it's always the moment when the square wave just begins to rise or is about to cut off.

I have a big ETD59 transformer which I am about to wind right now as i finish this and well let;'s attach that and see how this goes.

 

[jim hardy]

I lost faith in this or any other internet forum for that mater long ago, also because nobodies responding etc.

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