### Author Topic: High-power voltage doubler?  (Read 4757 times)

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#### ok_cool

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##### High-power voltage doubler?
« on: May 13, 2015, 01:19:14 am »
What am I doing wrong when I cannot get such thing to work? Is it simply not possible?

I need to step 12 volts up to 24 volts but my simulation simply doesn't work (yield the results I expect it to) when I run it with high loads and MOSFETs.

So is it even possible to get it done? Like amps and amps of current.

#### PSR B1257

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##### Re: High-power voltage doubler?
« Reply #1 on: May 13, 2015, 01:33:58 am »
Quote
I need to step 12 volts up to 24 volts
AC or DC?

Quote
but my simulation simply doesn't work
It would be good to see the circuit

Quote
Like amps and amps of current.
Define amps.
In theory, there is no difference between theory and practice. But, in practice, there is.

#### ok_cool

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##### Re: High-power voltage doubler?
« Reply #2 on: May 13, 2015, 01:55:27 am »
12A DC

#### ok_cool

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##### Re: High-power voltage doubler?
« Reply #3 on: May 13, 2015, 02:02:04 am »
But I mean, I only need the knowledge if it can be done. Like, if I can boost 12V to 24V at ONE MILLION amps.

Or if there is something that literally fucks it up.

#### PSR B1257

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##### Re: High-power voltage doubler?
« Reply #4 on: May 13, 2015, 02:11:37 am »
Quote
Or if there is something that literally fucks it up.
No, all a matter of money
In theory, there is no difference between theory and practice. But, in practice, there is.

#### ok_cool

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##### Re: High-power voltage doubler?
« Reply #5 on: May 13, 2015, 02:37:58 am »
Quote
Or if there is something that literally fucks it up.
No, all a matter of money

God damn man, now I have to figure it out on my own

#### PSR B1257

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##### Re: High-power voltage doubler?
« Reply #6 on: May 13, 2015, 02:46:21 am »
If you come up with a meaningful (or at least reasonable specified) question, you maybe get a meaningful answer.

« Last Edit: May 13, 2015, 03:11:38 am by PSR B1257 »
In theory, there is no difference between theory and practice. But, in practice, there is.

#### ok_cool

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##### Re: High-power voltage doubler?
« Reply #7 on: May 13, 2015, 03:19:13 am »
Too bad, I only want intelligent answers. If you know anything about anything you should probably be able to understand what I am after.

#### PSR B1257

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##### Re: High-power voltage doubler?
« Reply #8 on: May 13, 2015, 03:24:24 am »
Am I a clairvoyant, I don't think so.
In theory, there is no difference between theory and practice. But, in practice, there is.

#### ok_cool

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##### Re: High-power voltage doubler?
« Reply #9 on: May 13, 2015, 03:28:03 am »
Am I a clairvoyant, I don't think so.

That's a beautiful word.

#### Sebastian

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##### Re: High-power voltage doubler?
« Reply #10 on: May 13, 2015, 04:27:03 am »
What am I doing wrong when I cannot get such thing to work? Is it simply not possible?

I need to step 12 volts up to 24 volts but my simulation simply doesn't work (yield the results I expect it to) when I run it with high loads and MOSFETs.

So is it even possible to get it done? Like amps and amps of current.

What you need is a switched mode converter. Boost topology in your case.
What you are probably trying to use is a charge pump circuit, which is very uncommonly, or never, used for higher currents than a few hundred milliamps. (At least I can't think of any application where that would be useful.)

#### Neilm

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##### Re: High-power voltage doubler?
« Reply #11 on: May 13, 2015, 04:33:36 am »
What you need is a switched mode converter. Boost topology in your case.

Could also use a flyback circuit or resonant circuit - I have used both for step up applications which needed high voltage isolation.

One simple thing to try would be changing a couple of components - for instance I have had issues with some of the FETs in LTSpice not working correctly. Changing to another FET makes the simulation run.
Two things are infinite: the universe and human stupidity; and I'm not sure about the the universe. - Albert Einstein

#### Sebastian

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##### Re: High-power voltage doubler?
« Reply #12 on: May 13, 2015, 04:38:39 am »
What you need is a switched mode converter. Boost topology in your case.

Could also use a flyback circuit or resonant circuit - I have used both for step up applications which needed high voltage isolation.

One simple thing to try would be changing a couple of components - for instance I have had issues with some of the FETs in LTSpice not working correctly. Changing to another FET makes the simulation run.

Yep, of course there are topologies like flyback with isolated secondary side if you need that. Boost is just the simplest one.

#### ok_cool

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##### Re: High-power voltage doubler?
« Reply #13 on: May 16, 2015, 03:26:17 am »
What you need is a switched mode converter. Boost topology in your case.

Yeah that was my original design. 5 LTC1624 each boosting 12V to 33V at 3A each. But if I got my calculations correct the peak inductor current would be larger than my 6A inductors so it might require larger and more expensive inductors, so I thought maybe it would be possible to first use voltage doubler to do 12V to 24V and then boost it to 33V.
« Last Edit: May 16, 2015, 03:29:06 am by ok_cool »

#### ConKbot

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##### Re: High-power voltage doubler?
« Reply #14 on: May 16, 2015, 08:36:04 am »
No schmatic, just "simulation doesnt work, why?"

Sure, you can build a voltage doubler that can handle a few A. Big enough capacitors, big enough switching mosfets, and you're in business.

#### Delta

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##### Re: High-power voltage doubler?
« Reply #15 on: May 16, 2015, 09:40:50 pm »
If your simulator is running on a PC with a standard ATX PSU, then the maximum voltage it can produce is 12v.

#### Psi

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##### Re: High-power voltage doubler?
« Reply #16 on: May 16, 2015, 10:28:59 pm »
But I mean, I only need the knowledge if it can be done. Like, if I can boost 12V to 24V at ONE MILLION amps.

you would need liquid helium cooled superconductors to carry voltage that low with that current and not lose everything in the wiring.
Greek letter 'Psi' (not Pounds per Square Inch)

#### max_torque

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##### Re: High-power voltage doubler?
« Reply #17 on: May 16, 2015, 10:42:52 pm »
so I thought maybe it would be possible to first use voltage doubler to do 12V to 24V and then boost it to 33V.

It's "possible" to do pretty much anything, given enough money & Time.

However, (as far as we understand today) the lawd of basic physics cannot be changed  #startrek

So, no matter how many stages you use, increasing 12V to 33V is still a step up of 21V.

The efficiency of such a step up is broadly speaking determined by the resistive losses in the path across which the current flows. ie, the mosfets, inductors, capacitors etc in the circuit.

You may choose to do this power conversion in one step, or multiple parallel paths (21Vdc increase, but lower current per path, to limit the size of components, and bringing the advantages of a multiphase architecture to bear etc), or multiple series paths (ie a lower voltage step per stage, but each at full current).

Regardless, this doesn't somehow magically improve efficiency or make it easier to do.

Think about trying to lift 1 ton of rocks up to the 3rd floor of a building.   You could pay lots of people to each take 1 rock up, or pay a lesser number of stronger people to carry say 10 up at once.  In either case the work done is the same.  And although starting with those rocks already on the 3rd floor means they don't have to be lifted as far to reach the 3rd floor, how did they get to the 2nd floor in the first place?

#### mzzj

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##### Re: High-power voltage doubler?
« Reply #18 on: May 17, 2015, 01:45:51 am »
But I mean, I only need the knowledge if it can be done. Like, if I can boost 12V to 24V at ONE MILLION amps.

you would need liquid helium cooled superconductors to carry voltage that low with that current and not lose everything in the wiring.
24000 pcs of 1kW switcher modules wired in parallei, 25mm2 cable to each module,  busbars with 600000 mm2 = 0,6m2 cross section should do.

Smf