Inductor hysteresis losses?

[treez]

Hello,
We are designing a 4.19uH inductor for a 680W boost converter.
The inductor current peak is 49.5 Amps.
The inductor current trough is 39.4 Amps.

We are using a PQ40/40 core from EPCOS....as follows...
https://www.epcos.com/inf/80/ds/b65883a.pdf


We are using the core with N92 material, and will put a 3mm gap in it.
This way, 8 turns will give us an inductance of 4.19uH, and a saturation current level of 91.7 Amps.(300mT)

However, how, from the above PQ40/40 ferrite datasheet do we calculate what will be the hysteresis losses in this inductor?
Also, is the gap too large and does this mean it will give a poorly tolerant inductance value?

 

[mtwieg]

Core losses (which include hysteresis losses) should be estimated using nomograms from the material datasheet. You will need your approximate switching frequency and the peak-peak ΔB. However for a choke where the ripple to average ratio is small, these number will probably be off significantly, since the hysteresis curve changes significantly depending on bias field.

Gap size doesn't affect core losses (so long as ΔB is held constant).