High Frequency Transformer

Shadow_warrior · Aug 15, 2018

I need to buy a high frequency transformer. What are the steps I should follow for looking a transformer.
My input voltage(primary) should be around 60V and turns ratio be 8.5.
Primary Current 60 Amps.
Frequency of operation=10KHz

ronsimpson · Aug 15, 2018

There is no transformer like that.
You must design it and make it or have some one make it for you.

Shadow_warrior said:
turns ratio be 8.5

It is not clear if the turn ratio is 8.5:1 or 1:8.5. Is the transformer a step up or a step down?

Shadow_warrior said:
Primary Current 60 Amps

That is not easy.

Shadow_warrior said:
Frequency of operation=10KHz

Why so low? You can hear that. Most transformers for PWM operate more than 20khz so you can not hear the noise from the transformer.

Shadow_warrior · Aug 15, 2018

ronsimpson said:
It is not clear if the turn ratio is 8.5:1 or 1:8.5. Is the transformer a step up or a step down?

step up

Shadow_warrior · Aug 15, 2018

ronsimpson said:
Why so low

Because I dont want emi issues

ronsimpson · Aug 15, 2018

Shadow_warrior said:
Because I dont want emi issues

You will have EMI issues just lower.
There are many sources of EMI.

Shadow_warrior · Aug 15, 2018

ronsimpson said:
You will have EMI issues just lower.

Yeah I wanted lower EMI issues as I can not null it completely.

ronsimpson · Aug 15, 2018

Shadow_warrior said:
Primary Current 60 Amps.

This is very big wire. How are you going to do this? Even the 8A secondary wire is not easy.

Flyback? Forward? Center tapped? Resonant? Push pull forward?

cowboybob · Aug 15, 2018

Just curious Shadow_warrior:

What will be the source of the 60VAC, 60A, 10kHz signal to the xformer primary? And what will the xformer output (510VAC, ≈7A) be feeding?

(Just trying to suss out what you're up to ...)

Shadow_warrior · Aug 15, 2018

cowboybob said:
60VAC

it will be a transformer for isolated boost converter. So 30Volt dc will give 60Volt ac at primary

Shadow_warrior · Aug 15, 2018

ronsimpson said:
lyback? Forward? Center tapped? Resonant? Push pull forward?

full bridge

shortbus= · Aug 15, 2018

One thing not mentioned yet is, where will you find a ferrite core big enough for a transformer of this size?

ronsimpson · Aug 15, 2018

shortbus= said:
where will you find a ferrite core big enough for a transformer of this size?

Running at 100khz will reduce the core size.

ronsimpson · Aug 15, 2018

Shadow_warrior said:
My input voltage(primary) should be around 60V

Shadow_warrior said:
isolated boost converter. So 30Volt dc will give 60Volt ac at primary

Is any one but me confused?

Input voltage is 30 VDC 60A.
Full bridge.
Isolated.
Output voltage?

rjenkinsgb · Aug 15, 2018

I suspect he means a centre tapped primary with tap to V+ and push-pull drive.

(30V across each half winding in turn so 60V end-to-end.)

ronsimpson · Aug 15, 2018

rjenkinsgb said:
centre tapped primary with tap to V+ and push-pull drive.

Shadow_warrior said:
full bridge

schmitt trigger · Aug 16, 2018

This will be a full custom transformer that must be designed from scratch.

The classic book for high frequency transformer design is Colonel Mc Lyman's "Transformer and Inductor Design Handbook".
https://books.google.com.mx/books/a...p_read_button&redir_esc=y#v=onepage&q&f=false

Thru his company, he also sells a superb software package to assist you in the design:
https://kgmagnetics.org/?q=node/5

shortbus= · Aug 16, 2018

ronsimpson said:
Running at 100khz will reduce the core size.

But won't it still need to be large to fit the wire?

Shadow_warrior · Aug 16, 2018

shortbus= said:
But won't it still need to be large to fit the wire?

yes

ronsimpson · Aug 16, 2018

ronsimpson said:
Running at 100khz will reduce the core size.

shortbus= said:
But won't it still need to be large to fit the wire?

At 10lhz:
Set the primary inductance so there is some ripple. Current average is 60A. Turn on the MOSFETs at 54A and ramp up to 66A.
At 100khz:
Set the primary inductance so there is some ripple. Current average is 60A. Turn on the MOSFETs at 54A and ramp up to 66A.
The difference is that the 100khz transformer has 1/10 as much inductance or 1/3 as many turns.

ronsimpson · Aug 16, 2018

Full bridge. Two gate driver ICs (half bridge). Output inductor.

Is this what your are think of?

High Frequency Transformer

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