I need to redesign an old PFC for some higher input current and I have a problem with the space on my PCB. Now I use a ferrite core with a big air gap and 300mT maximum flux.
For the new choke, in order to have the desired inductance with the same core and bobbin size I will need a ferrite with 400mT capability. I saw that Feroxcube has a develop 3C92 material that can work at 400mT 100°C without a high drop in permeability value but unfortunately the are not so many core sizes available .Ideally I will like to find ETD34 size but a similar size with slightly diferitte shape will also fit in my board space. Did some one experimented other similar ferrite materials with high saturation flux density?

Daniel -- Ferroxcube will do ETD34 in the 3C92 material. Contact your local representative and they can confirm that for you.

Please remember that BH curves are always typical, not worst case. Make sure you have enough margin if pushing that far beyond 0.3 T.


They curves do look better, but there is always a tradeoff.

Daniel,
ETD34-3C92 can be made custom, but unfortunately it is not available as std. I would suggest to use ER28/17/11-3C92 or PQ32/16-3C92. Other option is to use ETD34-3C96: Bsat is slightly lower but not so much (440 vs 460 on spec @100º, 1200A/m)

I am not suggesting the core here. But I suggest you to re look at your design in two perspectives.1. 300mT or 400mT you mentioned, is that working flux density or worst case flux density? If it is steady-state flux, it would have lot of core loss. That makes the efficiency at liter loads to droop. Better to use more number of turns to reduce core loss

Thanks all for your suggestions. I will try to contact our transformer manufacturer for 3C92 material and maybe test it to see where saturates.
Hemanth, in this boost inductor application the core losses are small compared with copper losses, even if the core is magnetized with 300mT.