PFC Inductor design-core selection

Hello Friends,

I am designing a PFC Inductor for the 300watts

Input voltage range:85-265vac

Output voltage:400vdc

Switching frequency:100 khz

power:300w

I calculated the inductance required=754uH

Now i dont know how to select core for the same..??

Pls give me good approch so i can design the same inductor with toroid cores..

It is difficult to make PFC boost inductor with toroid core. Because making air gap in ferrite toroid is difficult otherwise go ahead with distributed air gap powder cores like MPP, High Flux

For this power rating, Ferrite N87 material PQ32 core with 1.5mm Air gap will be good
Or
26mm OD MPP core will suite

smijesh said:

It is difficult to make PFC boost inductor with toroid core. Because making air gap in ferrite toroid is difficult otherwise go ahead with distributed air gap powder cores like MPP, High Flux

For this power rating, Ferrite N87 material PQ32 core with 1.5mm Air gap will be good
Or
26mm OD MPP core will suite

Click to expand...

Hi smijesh, what parameters did you consider while selecting the core material for the inductor?
Also, how did you determine the required air gap?

- Rachit

Peak current and inductance are the input parameters when determing core size and µe respectively air gap.

Ferrite toroid isn't a useful option, either use powder core (e.g. suggested MPP material) which has built-in distributed air gap or a ferrite core (e.g. ETD or EC shape) with discrete air gap.

There are design tools for both core types available from core manufacturers, e.g. Magnetics or Epcos/TDK.

If you opt for powder core, don't forget to calculate the expectable core losses, otherwise you may experience an unpleasant surprise with 100 kHz operation frequency. The factor between useful and saturation flux can be rather large for powder core.

Yes also, try the "kool mu" core and its variants.
But i believe micrometals and others do it.
Also, i believe this gives you a non linear inductor...so there is a procedure for calculating it...in fact, as current increases in it, the inductance decreases.
You have to work from reluctance and go forward like that.

You have to build up the BH graph.....and do this using successive dB/dH calculations......you start off getting the ur at zero H, then you know that ur = dB/dH...so you have the gradient, and you follow this upwards to your next H point, (not too far away) then recalculate the gradient...then project that gradient forwards, and so on and so forth...till you have built up the whole BH graph, bit by bit.

i attach an example

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example core is APH46P60 by Amogreentech