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DC-DC converter with floating ground
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electrodacus:

--- Quote from: PlainName on December 30, 2023, 01:21:58 am ---Recorded for what purpose? What are you hoping to achieve?

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It was as a comedic response to him recording my answers :)
Whatever you say is recorded anyway by the forum.
Andy Chee:

--- Quote from: electrodacus on December 29, 2023, 11:10:41 pm ---Please just answer questions A) and B)

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Your analogy is flawed and incorrect. That's my answer.
electrodacus:

--- Quote from: Andy Chee on December 30, 2023, 03:51:15 am ---Your analogy is flawed and incorrect. That's my answer.

--- End quote ---

The questions are not about any sort of analogy.
So you are refusing to answer this questions because you are not sure about the correct answers ?
I'm just assuming that if you where sure you will had no problem answering whatever you think this is analog to some other type of problem or not.
EPAIII:

--- Quote from: electrodacus on December 28, 2023, 03:31:15 pm ---
--- Quote from: EPAIII on December 28, 2023, 06:32:39 am ---Yes, it may be possible to charge the series capacitor that you show and then reverse it's connections to place it is series with the battery to get a higher Voltage across the load FOR A SHORT TIME. But here's what the load will see as these processes happen, using YOUR second drawing, which I would modify.

1. First, starting with the capacitor discharged, it will look like a DC short so the load will see the full battery Voltage or +10 V.

2. As the capacitor charges that charge will show as an increasing Voltage that is bucking the battery so the load will see V2 as decreasing from +10 V down to zero or some lower number depending on how long the capacitor charging is allowed to continue.

3. Then the capacitor is reversed so it's +10 V is in series with the battery and the load sees +20 V for an instant.

4. Then the capacitor starts to discharge through the load and battery so it's Voltage decreases and the load sees a Voltage that decreases from the +20 V value back down to the +10 V value.

5. And it repeats. V2 looks something like this:

{My attachment should be HERE! But this stupid BB software does not seem to want that. I give up. It is below}

I would alter your drawing by having the battery Voltage connected to the load while the capacitor is charging. That way the half of my drawing below 10 V would become a straight line at 10 V.

But even that is NOT how I would double the Voltage to the load. I do not see any reason why a floating ground is needed in this circuit. I would use the battery Voltage to run a DC to AC converter which produces an AC Voltage. Then I would use a conventional Voltage doubler circuit (diodes and capacitors) to boost the Voltage to the 20 VDC level. This would include A GROUND connection to the battery minus terminal.

Or, BETTER YET, just use a DC to DC converter in boost mode WITH A GROUND connection to the battery minus terminal.

The "floating ground" buys you nothing in a battery powered circuit. The whole thing can float. It can float on top of 100,000 VDC if you wish and it will still work. Just turn the 100,000 VDC OFF before changing the battery.



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You are correct for the case where you reverse the connection of that capacitor you can get a peak of 20V but when it will discharge it will drop to zero not to only +10V as the capacitor is reverse charged.

My question was if there is any possibility to get V2 > V1 continuously not intermittent.
And the reason I ask this is because people claim that the mechanical analog of this circuit  can have V2 > V1 continually.
I was even banned on this forum for arguing that will not be possible.

The way I drawn the example with an MPPT DC-DC converter it is possible to  have V2 in the +5V and +30V range never get to zero but still it requires that V2 drops below 10V (below V1). It can be done even as +9V to +30V but it will be impossible to keep it  above +10V (above V1) continually.

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You are neglecting the battery Voltage.

And you were not clear as to the duration of the boost to +20 V. You talked about both continuously and for a brief time.

I only talked about what your second drawing suggested. I did not intend to completely rule out the possibility of a different circuit accomplishing "the impossible". I will not be so brash as to say that it is totally impossible. Just because one possible circuit does not do it, does not mean that none can.

You may want to take a course in logic.
electrodacus:

--- Quote from: EPAIII on December 30, 2023, 12:17:29 pm ---
I only talked about what your second drawing suggested. I did not intend to completely rule out the possibility of a different circuit accomplishing "the impossible". I will not be so brash as to say that it is totally impossible. Just because one possible circuit does not do it, does not mean that none can.

You may want to take a course in logic.

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I specifically mentioned that you can have any circuit you want in the green box as long as there is no energy in the box (so no batteries or hamster wheels in the box).

I will actually be so brash as to say that is totally impossible.
As far as I'm aware nobody has demonstrated that conservation of energy can be broken. So it will be logic to claim that any circuit inside the box will not be able to accomplish "the impossible".  Magic is not real despite multiple claimed evidence of magic smoke :)
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