3-phase power supply

[S. Petrukhin]

Dear friends,

I need to develop a low-power supply with an input voltage of 380V AC (540V DC).
Find it difficult to choose the components of the high part: the chip, the transformer. I don't know much about this topic.
This must be a line-voltage-rated power supply, without using zero, not 230V AC.

Can you recommend any solutions?
Maybe there are ready-made modules?

Parameters:

• input voltage 3 phase 380V AC
• output voltage 24V DC 1A

[drvtech]

You might find it difficult to get  such a small (24watt) one but this one fits the bill and is pretty good value considering the spec https://www.mouser.co.uk/ProductDetail/Delta-Electronics/DRP024V120W3BN?qs=Paqgc3NkMbQ5gVgkTVnbOg%3D%3D

[S. Petrukhin]

You might find it difficult to get  such a small (24watt) one but this one fits the bill and is pretty good value considering the spec https://www.mouser.co.uk/ProductDetail/Delta-Electronics/DRP024V120W3BN?qs=Paqgc3NkMbQ5gVgkTVnbOg%3D%3D

Thanks!
But sorry, I didn't specify: I don't need a ready-made device, I need a module for a PCB or a circuit diagram. 

[sandalcandal]

Given its such a low power requirement, is there any hard reason you can't just use a single phase to neutral and then just use a standard single phase module?

Edit: Sorry, didn't realise request was specifically for a no neutral, delta only system.

[drvtech]

He said "without using zero" which I take to mean "neutral" so I guess it's a delta only supply.  Still, it's no different from a 230V supply except that the reservoir capacitors, rectifier and switching transistor and a few other components need to be suitably rated for the higher voltage.
Edit - should have included the transformer in that list. Of course, if neutral is available then all you need is a standard circuit with a different bridge

[Circlotron]

For a 540V DC buss I'd see about using a half bridge.

[Miyuki]

He said "without using zero" which I take to mean "neutral" so I guess it's a delta only supply.  Still, it's no different from a 230V supply except that the reservoir capacitors, rectifier and switching transistor and a few other components need to be suitably rated for the higher voltage.
Edit - should have included the transformer in that list. Of course, if neutral is available then all you need is a standard circuit with a different bridge

Exactly, today are plenty of 1200V or higher voltage transistors
Just take any flyback and use a higher voltage transistor
Transformer can remain (if have enough insulation), just change output rectifier to higher rating
No big deal, just keep insulation distances high
//edit
and for brave enough just order some Chinese ones, they have 400V versions of that small bare board AC/DC

[Jeroen3]

Can you recommend any solutions?
Maybe there are ready-made modules?

ST has some parts in their VIPER series, but you're pushing it quite high that internal fets may not be feasable anymore.
TI also has many controller for this. Id recommend browsing through their catalog of reference designs to learn more theory.
Then buy an eval board and slowly merge it to your design.
This is a challenging endeavor, much cheaper and faster to use a off the shelf supply unit.

Ready-made board modules for this are very rare. But they do exist.
CUI AE40-UW-S24

[S. Petrukhin]

For a 540V DC buss I'd see about using a half bridge.

I do not know how to make a half-bridge in a 3-phase triangle.
In addition, the half-bridge will still give an amplitude value of 540V.

[m k]

Don't use a triangle, two phases are enough.

24W is not so much.
Is primary side passive attenuator out of the question?

[S. Petrukhin]

Can you recommend any solutions?
Maybe there are ready-made modules?

ST has some parts in their VIPER series, but you're pushing it quite high that internal fets may not be feasable anymore.
TI also has many controller for this. Id recommend browsing through their catalog of reference designs to learn more theory.
Then buy an eval board and slowly merge it to your design.
This is a challenging endeavor, much cheaper and faster to use a off the shelf supply unit.

Ready-made board modules for this are very rare. But they do exist.
CUI AE40-UW-S24

Internal fet more than 400B I have not seen, maybe not really understood the variety.
Perhaps the power part and the controller are not too scary for me, but the transformer is a disaster. I can't use an ordinary transformer that is used for 230V converters, isn't it?

The module you proposed is good, it would fit me completely, but the price is like for half an airplane wing. 

What do you think, if I use capacitors instead of diodes in a three-phase rectifier, will I get a C-voltage divider?

[S. Petrukhin]

Don't use a triangle, two phases are enough.

24W is not so much.
Is primary side passive attenuator out of the question?

Between the two phases, the line voltage is 380V (540v amplitude), I can't count on a phase voltage of 230V (310V amplitude) because the device will be installed on the side of the motor where have not neutral core in the wire.

I would like an honest power supply, isolated. And I don't really understand what is passive attenuator. Approximately as I suggested in the previous message?

[themadhippy]

I would like an honest power supply, isolated.

use a suitable rated tranny,380/415v primary to 24v is not a rare beasty for example https://www.ete.co.uk/product/transformer-380v-480v-to-24v-or-48v-50va-wide-input-voltage/

or if your feeling brave a 240v to 15v tranny is roughly the same ratio as 380 to 24

[S. Petrukhin]

I would like an honest power supply, isolated.

use a suitable rated tranny,380/415v primary to 24v is not a rare beasty for example https://www.ete.co.uk/product/transformer-380v-480v-to-24v-or-48v-50va-wide-input-voltage/

No, no, that much iron won't fit in my device. 

[S. Petrukhin]

What do you think about the serial connection of the windings of a 310V switching transformer used for switching power supplies in a 230V one phase network?

[Miyuki]

Cheapest way ...

https://www.aliexpress.com/item/32762537667.html?spm=a2g0o.productlist.0.0.7e676be8WHm8We&algo_pvid=f4b086f0-7927-4515-8b3e-87e183c633b1&algo_expid=f4b086f0-7927-4515-8b3e-87e183c633b1-28&btsid=2100bdcf16046786394757810ea4c0&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_

[akimpowerscr]

Quite simple and cheap with 3 little transformers for printboard 230V/18V 10VA...
https://fr.rs-online.com/web/p/transformateurs-pour-circuit-imprime/1707360/

[akimpowerscr]

A little explanation for who's are not electricians:

The primaries of the three single-phase transformers are star-connected.
There is no need for a neutral because the load is balanced.
Each primary therefore receives a voltage of 380V / 1.73 = 219V
The secondaries are delta-connected to balance the currents and eliminate harmonics 3.
The secondary voltage will be 18V x 219/230 = 17.1Vca
The rectified voltage will be 17.1Vca x 1.41 - 1.2V = 22.9V

If this voltage is insufficient, we can choose a secondary voltage of the transformers of 20V instead of 18V

[S. Petrukhin]

Quite simple and cheap with 3 little transformers for printboard 230V/18V 10VA...
https://fr.rs-online.com/web/p/transformateurs-pour-circuit-imprime/1707360/

Thanks!

It is a great idea to connect the transformers at the input according to the "star" scheme. But this is an expensive German manufacturer, and it will be difficult to get its products in Russia. Miniature transformers at 50 Hz are generally a rare device. 

[akimpowerscr]

The link I gave is just one example, there are dozens if not hundreds of manufacturers of miniature transformers.

These 50Hz transformers are found in many equipment.

It would surprise me very much that it is not found in Russia.

You should also know how many power supplies you expect to produce and sell.

If it's 10 units you won't be able to negotiate the components you buy, if it's 10,000 it can all be very different.

At a minimum, before rejecting a solution, you should make a serious analysis of what is available on the market and consult with Russian manufacturers of transformers.

[S. Petrukhin]

The link I gave is just one example, there are dozens if not hundreds of manufacturers of miniature transformers.

These 50Hz transformers are found in many equipment.

It would surprise me very much that it is not found in Russia.

You should also know how many power supplies you expect to produce and sell.

If it's 10 units you won't be able to negotiate the components you buy, if it's 10,000 it can all be very different.

At a minimum, before rejecting a solution, you should make a serious analysis of what is available on the market and consult with Russian manufacturers of transformers.

They are available from different sellers in Russia, but the price of three such transformers is more than the price of everything else in device. And these are unreliable suppliers: today they have a few pieces, and then wait six months for delivery. Unfortunately, we don't have our own Mouser, Farnell, DigiKey. Russian retailers are very lazy - they do not even bother to sell 1000 PCs. In fact, the only reliable and affordable supplier is LCSC.

I am developing a motor protection unit, I need power for several sensors, buttons, lamps. This is an unjustifiably high price.

[Jeroen3]

The three transformers is the simplest way to do it. Although heavy.
I didn't notice you were in russia, this probably makes the flyback approach very difficult to do since the many export restrictions on parts of US vendors.

However, russia does have access to the chinese market, right? So transformers or flyback controllers could be sourced there?

[akimpowerscr]

The advantage of the power supply that I proposed is that it is very reliable, especially with the transformer of the link which is of high quality and which meets the standards EN60742, VDE 0551, IEC 61558.

If it is a power supply intended to supply sensors, one cannot skimp on the quality, nor on the reliability.

With a switching solution, given the high rectified voltage (540Vcc) it will be very difficult to achieve a reliable power supply, especially for low power (24W).

[akimpowerscr]

I am developing a motor protection unit, I need power for several sensors, buttons, lamps. This is an unjustifiably high price.

That's not right.

The power supply is the most important item , if it fail, all will stop working.
How much cost every hour of brealdown?
How much cost to replace and to repair the power supply ?

So it MUST be very reliable and that justify an eventual high price.

[akimpowerscr]

If you choose the decoupage solution, such a power supply will certainly not be cheap.

You will need to protect it against power surges and transients.

There must be a tolerance of + 10% of the network voltage, so a rectified voltage can reach 594V

1) to protect the rectifier diodes against industrial electrical network transients, 3 x 50Hz protection induxtances should be placed at the input.

2) with such a high dc voltage, the best configuration in order not to stress the components too much (transformer, semiconductors) is the forward configuration with 2 switches with reset of the core.

https://www.onsemi.cn/pub/Collateral/TND378-D.PDF

The voltages in a flyback configuration are too high especially since the dimensions of a 25W ferrite transformer are very small.

You will need to use quality components which will not come cheap.

NB: I apologize to the moderators for having published 3 answers by following, but I did it for clarity because they relate to 3 very distinct points of view