Measuring the parameters on a LLC transformer?

[TroelsM]

Hi.

For an amateur LLC looks very interesting for these reasons: lower EMI and the possibility of separating the pri and sec winding.
We all like low EMI and if the windings are separated on the former it becomes much easier to make a safe transformer.

But LLC also makes the transformer more complicated. if the resonant inductor is included in the Xformer we have 3 inductances to watch for:
- the leakage inductance
- the magnetizing inductance from the airgap
- the "ideal" inductance in the winding.

Correct?

For an amateur working with unknown materials and limited time to do a lot of math (me!) it would be great if we could measure the inductances in different Xformer designs.

So how to do that?

For an transformer without airgap we can measure the inductance on the primary with, and without, shorting the secondary.

Any ideas on a simple way to measure LLC X-former parameters?

Kind regards

 

[steven]

Hello,

I do not have (yet) experience on LLC X-former, but i think you can use the same measurement methods than "usual" SMPS x-former (short circuit secondary). As you must know, air gap have a big influence on inductance.