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I am working on the design and prototyping of a boost conductor. With that task in hand I have to design a DC inductor for a boost converter. I am using the material EPCOS N27 since its the only one available to me. My RMS current through the inductor 8.9S and I am using a switching frequency is 150kHz. My question is what is a good selection of flux density and specific power density for this design using the N27 and how does one generally go about selecting these variables. N27 datasheet

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  • \$\begingroup\$ What’s your current ripple? \$\endgroup\$
    – winny
    Commented Sep 11, 2020 at 22:43
  • \$\begingroup\$ My allowable current ripple should be less than 20%, so its 1.3A \$\endgroup\$
    – Kevin
    Commented Sep 11, 2020 at 23:34
  • \$\begingroup\$ "I am using the material EPCOS N27 since its the only one available to me." - what exactly does this mean? \$\endgroup\$ Commented Sep 12, 2020 at 6:27
  • \$\begingroup\$ Sounds like you will be closer to saturation limit than thermal limit. \$\endgroup\$
    – winny
    Commented Sep 12, 2020 at 9:49

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My question is what is a good selection of flux density

enter image description here

I wouldn't want to go above a peak flux density of 350 mT at 25 degC falling linearly to 300 mT if the core rises to 100 degC.

My question is what is a good selection of ...specific power density for this design

Now that depends on a few more things (as well as hysteresis loss implied by core saturation being kept reasonably low). So, work out what H field you will apply to avoid excessive flux density, add gapping if needed (it easily could be needed) and then work out what copper losses you might get with the extra turns (due to gapping) and take it from there.

If it's just core energy density you are considering, this is a guideline from the data sheet: -

enter image description here

But, to transfer this to your design you need to know the volume of your actual ferrite core and this isn't available in the material specification you posted a link to. Note that they are using 200 mT as the peak flux density.

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