Note that for a ~100W at 40KHz, you get a ΔB of under 250mT, so your Bmax will be around 125mT, much less than Bsat.
Thanks, this sounds like the spec for the Epcos TDK PM62/49 core in N87 material.
Ferrite databook of Epcos
https://en.tdk.eu/blob/519704/download/2/ferrites-and-accessories-data-book-130501.pdf
it also sounds like being from page 49 of the above databook? .....ive just noticed that says its for "ring cores", and I wonder if that still makes it applicable for say PM62/49 and other core shapes.
I appreciate that we can all only work to the data given to us, and in the case of core loss data, its always a little ambiguous, what we are served up with by the manufacturers. And of course , industries have utterly no desire for the manufacturers to make the data better presented as their competitors would then grab it.
its worth noting that page 49 of the above databook also conforms to 100degC, and ferrites can operate above 150degC, so page 49 is a little conservative...and Delta B could stretch up to further than the 125mT peak of the databook.
The article by Billings in #7 is very good, but Billings does not say what "core area product" is. I think its core cross section area multiplied by the "winding area"(?), but what the "winding area" refers to I have no idea.
Ive recently been testing a 3.5kw LLC resonant converter vin = 390vdc vout = 250-400vdc, Fsw=100khz at max load and the transformer core was tiny!....about a 6cm by 5cm ETD shaped core. it was a water cooled smps though. The transformer primary had an inductor of 74uH in parallel with it, -so that they can get the circulating current up without overheating the transformer..the 74uh inductor though was just about 3.5cm by 2.5cm by 2cm.
I just cant believe that there delta B in that tiny core was less than 400mT.