Ferrite core transformer design step by step

[Aucosticraft]

I am looking for practical design of transformers ( ferriet core). its considerations, selection calculations step by step.

for example

a transformer to work on PWM. where duty can vary from 30% to 99%.
frequency of operation is 60khz.
primary voltage is : 21.6V secondary peak voltage is 400V. the ouptut current should be 5Amp.

so if I take above as a input for ferrite core transfrmer design, then what will be the practical steps which need to be followed.

a) like based on Fq, selection of material.
b) size of core.
c) winding turn calculations with wire thickness.
d) something inductor value of the transformer coil( what is its significance)

I have tried to read other threads too they give some information but not enough to built your own. I have also tried to read online information.
but feel lost and at the end feels like back to the square one.

[dtproff]

Try post 8 here. There are some other links in the thread that may also help.

McLyman is probably the single best book I read on the subject.

http://www.amazon.com/Transformer-In...8105453&sr=8-1

Tony

[dtproff]

Sorry forgot the other thread... DCM & CCM DC-DC flyback converter help plz

Tony

[GloBug]

What are you building?
Sounds like a big transformer. Can the 21.6v source supply the 2000watt load your adding to?

Take the little bits of information you can find and put it all together. Like a mosaic.

a) I don't know
b) I don't know
c) The turns is a ratio, there are lot's of threads here for calculating the turns ratio of a transformer. Wire thickness will depend on the VA needed and I don't know. Bigger wire for more current.
d) I don't know what your saying. Do you want to know the inductance of this imaginary transformer?

The threads you have read must have some information, find specifications of already made transformers similar to yours, this will also lend some clues.

There is no "step by step" that I have come across, I have not looked hard. However I have seen the odd chart pop up now and again with lot's of useful information.

[dtproff]

GloBug

This was for a flyback transformer, 85W peak power, 32V output, 65KHz, EE2525 Crore using Acme JPP-44 material.

Hope that helps.

Tony

[Aucosticraft]

@ dtproff

Thanks for the pointers. I managed to get the book you suggested. but still I am toddling to understand it.

friends,more helpful words on the topic would be welcome.

[ChocoHolic]

Oh, ohh... Toni's first post translates to me like:
...optimized transformer design, especially for higher power, cannot be taught by three sentences in a few postings.

I would support this view.
Despite their simple appearance magnetics are a complex design topic.
In addition to the fundamental theory + HF effects a transformer always is key component of a certain circuit. Depending on the circuitry you will need remarkably different designs. Last but not least safety isolation can be a serious concern.

But even if someone of the experienced members would agree on giving you many hours of support for your specific application, means doing the design for you and explain the reasoning behind... - without detailed description of the intended circuitry and mode of operation nobody can help you.

If you are looking more for a general learning about magnetics, then there is no way around books and further online search and practical verification of multiple designs.

[dtproff]

Originally Posted by Aucosticraft

@ dtproff

Thanks for the pointers. I managed to get the book you suggested. but still I am toddling to understand it.

friends,more helpful words on the topic would be welcome.

Tell you what I will do... If you will work with me over the next few days/to a week I will walk you through the design process step by step.

I need a couple things first...

Peak Power Rating
Input Voltage range
Output Voltage

I will then guide you through the various topology decisions, design choices and a detailed walk-through of the math and what it means.

How about it?

Tony

[dtproff]

ChocoHolic is right on the complexity of the power supply.

There was a time several years ago that a few people spent some time keeping me on track so that I didn't go off in the weeds. I am especially thankful to a friend of mine who was one of the best magnetics engineers I have ever had the privelage of working with.

So maybe this is a chance to give back.

Tony

[ChocoHolic]

Stunningly generous offer!!