energy stored in the inductor

[The_Babatian]

I got a question regarding where the energy is stored in the inductor.
The inductor, for example in the buck converter, has a DC current and AC current in the steady state. My understanding is that the energy corresponding to the DC current is stored as magnetic field in the air gap and the energy corresponding to the AC current is stored as magnetic field in the core, but since the average AC current over a switching cycle is 0, so there is actually no energy stored in the core over a switching cycle, am I right?
Thanks in advance!

 

[mtwieg]

Energy storage won't distribute itself according to frequency... the flux in the core and the gap should always be equal (or roughly so, for small gaps and little leakage), and stored energy should be related to flux according to magnetic reluctance. So as long as reluctance is constant with frequency (it should be) so will energy storage.

Dissipated energy, on the other hand, will not shared equally and that will probably depend on frequency.

 

[The_Babatian]

Thanks for reply, I think I do not get it, where do you think is the energy stored in the inductor, the air gap or the core, or both?

 

[mtwieg]

Energy will be stored in both, in some ratio equal to the ratio of their reluctances. So long as the reluctances are fixed, the distribution of energy won't change.

If the air gap is large (large reluctance relative to the reluctance of the core), then most energy will be stored in the air gap. But this has nothing to with whether the signal is AD or DC.

 

[The_Babatian]

That makes sense !! Thank you!!