Get the data sheets and applications manuals from a reputable manufacturer. They will give all the information you need. They may well offer programs or apps which do it all for you, too.

Yes, guidance given by Tony Maine is absolutely correct. I would like to add something......

First identify your application. Then decide the Topology depends upon the Power requirement.

Example: Flyback upto 100W , Push pull upto 600Watts or Half bridge, more than 600 watts use Full bridge etc.

Now I advice you to be practical. If core which you get from Local shop, do not become so aggressive and go for more than 40-50Khz operation. Your magnetic may not work for more frequency and core will become very hot and affect efficiency.

Use bifillar winding depend upon boost or buck type of configuration.(bifillar at primary if boost/ bifillar at secondary if buck converter).

Sandwitch secondary between primary for reducing back-emf and high degree of magnetic coupling.

you may ask any thing on this if you face any problem.

Dear Tony Maine

I did what you told me ....... ferroxcube data sheet provided ratings are low.

I want to design higher power application ferrite core transformer.........

So, ferrite material is available and i have to cut the material using laser according to my own dimensions..

so i want to ask you.... is there any way to design dimensions or its simply according to my requirement (i.e window winding area or pole width and core area).

Thanks in advance for your time

Dear Umair Tahir,

Can you specify the number i.e., intended operating frequency and wattage for your project.

This is very tricky to answer without actual numbers.

Dear Sharan Dilip ,

Its 25 kHz & 100kVA.

Umair Tahir

May I know the voltage?

You might look at the Magnetics Inc type 9740, It should be able to handle 100kVA (though I haven't done the calculation!) It's a toroid so you might have to wind it by hand. Make sure all your winding are multistranded wire and well insulated.

Dear Sir

Thanks a lot for your suggestion.

But i guess flux linkage and coupling coefficients are low for toroid core as compared to shell type. Plus magnetization losses are more of toroid.

so, what are your opinions regarding size of the toroid transformer.? To achieve smallest possible size is also my design constraint...

I think you'll find that coupling inductance depends more on the winding geometry than the type of core. The more interleaved the windings are, the higher the coefficient. But cores of either type must be readily avaiiable as they are used in machines like electric vehicles.