How to calculate hysteresis core loss of this flyback?

[grizedale]

How to calculate hysteresis core loss of this flyback (& temp rise)?

Hello,

Please can you help to find the temperature rise due to core loss of the following smps?

I do 43W offline flyback (at 70KHz).

The primary coil current is as follows............

https://i42.tinypic.com/jb7asy.jpg


The ferrite core is ETD29/16/10 with 0.5mm gap (N87 material).....................

https://www.epcos.com/inf/80/db/fer_07/etd_29_16_10.pdf

How can i now go and calculate the core hysteresis loss?
(...the ferrite datasheet does not give graphs of loss vs frequency and delta B.)

 

[atripathi]

Some of the Ferrite vendors (Ex: Feroxube) do provide an empirical formula for core loss calculation. This is function of B & F. It is typically of this form

Pcore (mW) = K1fxBy × Ve
Where:
K1 = Constant for core material
f = Frequency in kHz
B = Peak Flux Density in kGauss
x = Frequency exponent
y = Flux Density exponent
Ve = Effective core volume (cm3)

Try this and see if this helps

https://www.ferroxcube.com/appl/info/plandesi.pdf

 

[grizedale]

OK thanks, though i think working out the power dissipation in the core is one thing...but then translating this into the core temperature rise is another thing entirely.