pi expert

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Hello Pi-expert,

I want to add shield windings between primary and secondary of flyback transformer. The design used here is of link switch.When I add shield winding using pi-expert suite tool, I get cancellation winding. Apart from cancellation shield, I need another shield between primary and secondary using tool. How do I add this using the tool?

 

Which LinkSwitch are you referring to?

In case of LinkSwitch-CV, the design methology dictates that only a single primary cancellation winding can exist i.e the program is not capable of adding a shield between the primary and secondary.

I used the PI transformer design program for LNK III also and it puts the cancellation winding on first before winding the primary.

It also doesn't fill the bobbin width. It puts the feedback winding between the primary and secondary and uses quadfilar which fills the bobbin width. So I think that should actually be the cancellation winding. So I think there is an error in the software!!  

 

I used the PI transformer design program for LNK III also and it puts the cancellation winding on first before winding the primary.

The location of the cancellation winding is based on empirical results from the bench for best EMI.

 

 

It also doesn't fill the bobbin width. It puts the feedback winding between the primary and secondary and uses quadfilar which fills the bobbin width. So I think that should actually be the cancellation winding. So I think there is an error in the software!!

The feedback winding is put in between the primary and secondary to ensure the best coupling since this is a primary side feedback device and is not a cancellation winding in any way. Hope I have clarified your queries.