Hello,
I've built an inverter with current measurement using current transducers (CT) in each leg.

Simulation works fine except CT part.
There is a problem with the current on the secondary side (L6,L8) of the CTs. Current in L6, L8 is not zero (ca.0.5A offset) when current on primary side (L5, L7) is zero.

I tried changing orientation of secondary side coils (windings beginnings) but didn't help.

Can you tell me why there is an offset on the secondary side of CT?

Thank you.

 

Hello,
I've built an inverter with current measurement using current transducers (CT) in each leg.

Simulation works fine except CT part.
There is a problem with the current on the secondary side (L6,L8) of the CTs. Current in L6, L8 is not zero (ca.0.5A offset) when current on primary side (L5, L7) is zero.

I tried changing orientation of secondary side coils (windings beginnings) but didn't help.

Can you tell me why there is an offset on the secondary side of CT?

Thank you.

Is Ucomp a negative voltage when the secondary currents are flowing?
Part of your schematic is obviously missing. Can you post the .asc file for the entire circuit, so we can simulate it?

 

1. Are you saying it is a DC current?
2. Is there a voltage across L6 & L8 as well?
3. Could there be a -ve voltage feeding back via Ucomp?

Regards,
Ifixit

 

Hello,
Thank you for your answer.

Can you post the .asc file for the entire circuit, so we can simulate it?

Simulation in the attachment.

Steady state @ ca.8ms
Inverter leg current (primary) - L5, L7
Inverter leg current (secondary) - L6, L8
Primary trafo total current - L3
Primary trafo voltage - U1-U2

 

R7 & R10 should be the terminating resistance (4r8) so that both polarities of the signal are terminated equally. Change R5 to 10K to to provide the proper smoothing of the DC output, Ucomp.

Regards,
Ifixit