DC to DC step up

[DominickSch]

I have been looking for a schematic for a DC to DC step up

I'm needing to go from 48v DC to 170v DC and probably over 6000 watt on the 170 side.
I'm hoping to stay away from transformers and tune it to be as efficient as possible.

I appreciate your help,
Dom

 

[itsmoked]

You are dreaming...

You will need a transformer. You should look at SEPIC designs.

By the way a 6kW supply like you're proposing is major league. I hope you've done a few 1 or 2 kW projects to warm up with.

If you need just one unit, buy a really big inverter and hack it. You will save a huge amount of time and money.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[DominickSch]

Thanks for the reply.
And yeah I agree after hitting the submit button I did a little more research and was like yeah its going to need a
transformer.

I asked the question because I'm always under the impression
that transformers are parasitic up the voltage and the current goes down And obviously I need the current.

 

[IRstuff]

And, not overtly mentioned, 6kW at 48V is not exactly a trivial matter. 125A continuous requires LARGE cabling.

TTFN

FAQ731-376

 

[Skogsgurra]

Your saying that "transformers are parasitic up the voltage and the current goes down" is quite true - except that 'parasitic' part. You can not have voltage up and keep current. That would violate conservation of energy. At least if you want it to be true over any time.

Gunnar Englund

http://www.gke.org

--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[DominickSch]

Yeah I took the large cabling into consideration.

And true true so what you put in you basically get out
just higher voltage and lower amperage.

So it would be somewhat safe to say that the wattage would almost be the same on both sides?

 

[VEBill]

If you get more 'wattage' (power) OUT than IN over an extended period of time, then there's a Nobel Prize in your future.

 

[DominickSch]

HaHa that would be awesome tho we all know that's not possible.

Anyways I'm gathering I should be stepping this up with
High frequency transformer only problem is every one of these
transformers I look at are small I do not see how they could pass that much amperage. Or I'm looking at it in the wrong way.

 

[IRstuff]

You need to be looking for a transformer that's in the power substation class. 6kW transformer is not something you'd find at your typical circuit component supply store.

Just think about primary windings that look like battery jumper cables.

TTFN

FAQ731-376

 

[itsmoked]

Yep, and semiconductors to handle that same current.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[IRstuff]

And, to be frank, this is not something for a neophyte. The currents are high enough that any error in fabrication or design is likely to result in an instant conflagration.

Having evperienced one myself as a frosh, it ultimately determined that I would graduate as a digital EE from college.

TTFN

FAQ731-376

 

[DominickSch]

cool thanks for the help I see that this will all be all about the transformer.

And no offense But little quick to assume I'm a beginner
specially considering you don't know my background.

But I understand what your saying

 

[waross]

Look for a transformer core and roll your own.
The KVA capability of a core is roughly proportional to the frequency. The maximum Volts per turn is also roughly proportional to the frequency.
Now, you've found a core, but there is not enough space for your windings. Double the frequency and the Volts per turn. Now you need only half as many turns for the same result.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[VEBill]

Even at HF frequencies, 6kw-anything normally sits on the floor, not on the desk. Even with *AIR* cores in the power circuits.

 

[ScottyUK]

I've posted this recommendation before: look for the book 'Soft Ferrites' by Edgar Snelling. It's out of print and second hand copies go for a high price. It's in the reference list for almost any book on HF power transformer design written today, even though the original text was written forty years ago.


----------------------------------

If we learn from our mistakes I'm getting a great education!

 

[sreid]

For experimenting only, 208 VAC Three Phase can give you about 170 VDC at plenty of amps [say, 50 amp service].

208 RMS/(3^1/2) = 120 VAC RMS Phase to Neutral

120 VAC RMS x (2^1/2) =169 V Phase to Neutral Peak

Then 3 Phase half wave rectify and capacitor filter.

 

[danonboost]

Too little info upfront to really help you.

So, I'll just make things easy. Use 110VAC with a redonkulously large capacity full bridge (or parallel them) and a bank of caps to match.

This will give you about 170VDC. Also buy health insurance.

dan

 

[RajeevCell]

DominickSch,

We do not know what you'd do with the 170 VDC output. Are you trying to get 115 Vac from 48 VDC batteries? For telecomm?

If so, then the best way would be using an off-the-shelf inverter. There are plenty of commercial units available for converting 48 volt DC to 115/230 volt ac.

If your main business is not power electronics, then there is absolutely no benefit in developing a 6kW inverter by yourself.

 

[peebee]

I'm also very very curious about why you want to build this, what you want it for.