Current transformer measurement vs actual MOSFET drain current

[Magnethicc]

Hi everyone.
I am doing a high current resonant converter (full bridge) where the RMS current in the Primary of the converter is about 33amps.
I have a series current transformer to sense the current in the primary (1:200 turns ratio). When I look at the current coming out of the current transformer it is very noisy and sensitive especially in no load.
I tried to put a wire loop on the drain of the MOSFETs and the current measurement is much more clear and clean down to no load.
The problem with it is that the wire loops add to the inductance for the resonant which changes the resonant frequency of the converter.

Does anyone have a tip on how to do the current measurement best way?

 

[KlausST]

Hi,

What is a "wire loop"?

As always: textual description is unsuitable to get a clear view of your situation.
--> post:
Schematic, PCB layout, photos, scope pictures..

Klaus

 

[Easy peasy]

Is your transformer in series with the transformer ? or one of the totem pole legs ?

in any event - you need to shield the wire that goes thru the CT - this will cut out a lot of noise ...!