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MOSFET (Si/SiC) Forum Discussions

User21657
Level 1
First question asked First reply posted
Level 1
Hi,
Kindly help in designing custom transformer for same EVK. Provide any sheet to design transformer from scratch.
I have calculated inductance and turn ratio. I am not able to determine how much turns to use in primary or secondary.
Example: Turn Ratio: 5:1
primary turns can be 5 or 10 or 15 any... So in this case how to choose number of turns?

Vikas Dabas
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1 Solution
Abhilash_P
Moderator
Moderator 25 likes received 250 replies posted 250 sign-ins
Moderator
Hi,

Please find below the link to download the handbook for HFT design.

https://www.engineeringbookspdf.com/download/?file=3818

This book has example case studies for fly back as well as half and full bridge transformer design. It is a step by step guide for transformer and inductor design.
Let me know if this helped you in your transformer design.

Regards,
Abhilash P

View solution in original post

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5 Replies
User21657
Level 1
First question asked First reply posted
Level 1
Hi,
Kindly reply.
Vikas
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Srivatsa
Moderator
Moderator 5 sign-ins 50 replies posted 25 solutions authored
Moderator
Moved post to the right forum.
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Abhilash_P
Moderator
Moderator 25 likes received 250 replies posted 250 sign-ins
Moderator
Hi,

The number of turns on the primary and secondary depends on the following,
1) The turns ratio.
2) The voltage per turn rating of the wire used in the transformer winding.
3) The total copper losses expected.
4) The size of the transformer.
5) The window area.
6) The type of core used ( Flux density dependency)
7) The transformer shouldn’t enter the saturation region. (Ni limit vs AI value)

Please find below the variation of peak flux density with an increase in primary turns,

5109.attach

For detailed transformer designing, please refer the following links,

https://techweb.rohm.com/knowledge/acdc/acdc_pwm/acdc_pwm05/6734
https://techweb.rohm.com/knowledge/acdc/acdc_pwm/acdc_pwm05/6823

For detailed design of Converter magnetics, please refer to the following link,

https://www.ti.com/seclit/ml/slup132/slup132.pdf

Regards,
Abhilash P
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User21657
Level 1
First question asked First reply posted
Level 1
Abhilash P wrote:
Hi,

The number of turns on the primary and secondary depends on the following,
1) The turns ratio.
2) The voltage per turn rating of the wire used in the transformer winding.
3) The total copper losses expected.
4) The size of the transformer.
5) The window area.
6) The type of core used ( Flux density dependency)
7) The transformer shouldn’t enter the saturation region. (Ni limit vs AI value)

Please find below the variation of peak flux density with an increase in primary turns,

5109.attach

For detailed transformer designing, please refer the following links,

https://techweb.rohm.com/knowledge/acdc/acdc_pwm/acdc_pwm05/6734
https://techweb.rohm.com/knowledge/acdc/acdc_pwm/acdc_pwm05/6823

For detailed design of Converter magnetics, please refer to the following link,

https://www.ti.com/seclit/ml/slup132/slup132.pdf

Regards,
Abhilash P


Thanks for reply. But i have gone through this theory multiple times and unable to conclude.
Kindly provide step by step design guide. All points suggested above are known but dont know how they affect number of turns.
If possible, please share example of transformer design. You have multiple design of 3.3KW full bridge. You can take any transformer specs and choose core and number of turns.

Regards
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Abhilash_P
Moderator
Moderator 25 likes received 250 replies posted 250 sign-ins
Moderator
Hi,

Please find below the link to download the handbook for HFT design.

https://www.engineeringbookspdf.com/download/?file=3818

This book has example case studies for fly back as well as half and full bridge transformer design. It is a step by step guide for transformer and inductor design.
Let me know if this helped you in your transformer design.

Regards,
Abhilash P
0 Likes