DC-DC converter with floating ground

[magic]

a) V1 is always 10V (battery voltage).
b) V2 can be made to fluctuate between 5V and 30V using just that green box with only two wires connected to it.  There is no battery in the box but there are multiple capacitors, inductors, mosfets and even a micro controller.

Is your claim that is not possible ?

Is it possible to have the V2 fluctuating between 5V and 30V ?
If not why ?

Do you have an answer to this problem ?

Is it possible that you have a brain and could start using the answers people posted to solve your trivial problems?

Or is this some sort of democracy where truth is established by a majority vote?

[electrodacus]

Is it possible that you have a brain and could start using the answers people posted to solve your trivial problems?

Or is this some sort of democracy where truth is established by a majority vote?

It is a physics problem and this is a sort of survey.
You say the problem is trivial and maybe it is for you but based on other comments it does not seem to be trivial.

I will love to know your answer. I gave mine in the original post.

[boB]

How about an LTspice simulation of one of the answers ?

[electrodacus]

How about an LTspice simulation of one of the answers ?

Is this a question directed to me ?
There are two questions A) and B) in the original post with my answers in bold No and Yes.

A) Is it possible for V2 to be a constant 30V?  No
B) Is it possible for V2 to peak to 30V multiple times while V2 never drops below 5V ?  Yes

So do you not agree with one of my answers ? Or with both ?

If you say Yes to question A) the it will be you that will need to prove that as I can just use an empty box or a wire between the two points and made my case.
If you say No to second question I can describe to you how it will work but the diagram I offered as an example should be sufficient.

The capacitor will be disconnected from the two box terminals and connected to the output of a DC-DC boost converter.
The boost converter can be a max power point so one that maintain a constant voltage at the input and takes what is available.
So say DC-DC MPPT is set to 5V then the other 5V will drop across the 100Ohm resistor meaning 50mA will flow trough the circuit.
5V * 50mA = 0.25W are available with say a 70% efficient DC-DC converter 0.175W are available to charge a large electrolytic capacitor connected at the output of this DC-DC converter.
When this capacitor gets to 20V some analog trip circuit can disconnect the DC-DC and connect the capacitor between the two connection points on the green box.
Thus for a short moment V2 = 10V + 20V = 30V
It can get way more complicated than this with a microcontroller and current measurement to calculate exactly what the resistance value is and what the battery voltage is but this are unnecessary complications just to say that it can be done.

[Andy Chee]

So do you not agree with one of my answers ? Or with both ?

In order to resolve disagreement, we need proof.  Ltspice simulation can be used as proof.

[electrodacus]

So do you not agree with one of my answers ? Or with both ?

In order to resolve disagreement, we need proof.  Ltspice simulation can be used as proof.

As I mentioned above for question A) it will be you that needs to provide the proof.
The question B) I explained in details so it should be sufficient proof but it can be arranged to be simulated in LTspice tho it will take time as it is a relatively complex simulation due to switch logic involved.
They should likely already have some DC-DC boost converters with max power point tracking so that part should be easy.

I provided spice simulation as proof for the Veritasium video on how electricity works and it was of no help. If people do not understand the basics a simulation or even an real experimental demonstration will not help with anything and cost me time.

[Someone]

A) Is it possible for V2 to be a constant 30V?  No
B) Is it possible for V2 to peak to 30V multiple times while V2 never drops below 5V ?  Yes

So do you not agree with one of my answers ? Or with both ?

Now that you have stated a somewhat clear question who has disagreed with you? No-one! So why immediately ask if every poster agrees/disagrees?

[soldar]

I'm more used to having the signal flow drawn from left to right, but whatever.

Me too. Power, voltage, signal flow from left to right and from top to bottom. I often redraw schematics that way because it helps me analyze and understand the circuit.

When I reverse engineer a circuit I start out with a schematic which resembles the PCB but I rearrange it in steps until it is easier to conceptualize.

[tggzzz]

Is A) or B) possible ?  (see original post as it was edited recently and the two questions where added).

... and there we have it. Changing the post to make it look like people are disagreeing with you. There was no need to edit the original post when you can just add your new argument inline. Now we'll have to aggressively quote everything you say to keep the discussion coherent.

The post change can not make people agree or disagree with me. It is to make it simpler to answer with Yes or NO to A) and B)
Those that answered before the two questions where added never mentioned A) or B)
The question was always the same and yes people where not all in agreement with me or with others before or after I added the questions to original post.
It is a problem and based on feedback I can improve the formulation to make thing more clear.
So what is your answer ?

The acceptable way to change your opinion is:

• add a new post indicating your new opinion
• optionally changing the early post, using strikethrough to indicate what you no longer wish other people to consider, and adding "EDIT: ..." to show your new opinion.

Doing that makes you appear to be thoughtful and considerate.

"Silently" changing the early post makes you look like an insecure troll.

[IanB]

There were people in the past that disagreed with the fact that V2 can not be continuously higher than V1 despite the floating GND.

You would need to provide a context reference for that statement, by quoting instances where "people in the past" said this.

[Andy Chee]

There were people in the past that disagreed with the fact that V2 can not be continuously higher than V1 despite the floating GND.

You would need to provide a context for that statement, by quoting instances where "people in the past" said this.

I can provide context.

The DC-DC floating converter problem is supposed to be an electrical analogy to describe the energy interactions behind Veritasium's/Xyla's "downwind faster than wind" vehicle.

"people in the past" is a reference to people discussing the vehicle physics, as opposed to the DC-DC converter problem.  But the OP believes they are directly equivalent.  Go figure.

[IanB]

I fully understand that context. I knew what this was about from the very first post in the thread, since we've been here before.

But I want electrodacus to provide a direct quote where someone said the DC-DC converter could provide a continuous step up in voltage without a third electrical connection. Otherwise he is just being disingenuous and misrepresenting people.

Because I really don't believe anyone on this forum would be likely to say that about the "DC-DC converter" picture in the first post.

[Zero999]

How about an LTspice simulation of one of the answers ?

Is this a question directed to me ?
There are two questions A) and B) in the original post with my answers in bold No and Yes.

A) Is it possible for V2 to be a constant 30V?  No
B) Is it possible for V2 to peak to 30V multiple times while V2 never drops below 5V ?  Yes

So do you not agree with one of my answers ? Or with both ?

If you say Yes to question A) the it will be you that will need to prove that as I can just use an empty box or a wire between the two points and made my case.
If you say No to second question I can describe to you how it will work but the diagram I offered as an example should be sufficient.

The capacitor will be disconnected from the two box terminals and connected to the output of a DC-DC boost converter.
The boost converter can be a max power point so one that maintain a constant voltage at the input and takes what is available.
So say DC-DC MPPT is set to 5V then the other 5V will drop across the 100Ohm resistor meaning 50mA will flow trough the circuit.
5V * 50mA = 0.25W are available with say a 70% efficient DC-DC converter 0.175W are available to charge a large electrolytic capacitor connected at the output of this DC-DC converter.
When this capacitor gets to 20V some analog trip circuit can disconnect the DC-DC and connect the capacitor between the two connection points on the green box.
Thus for a short moment V2 = 10V + 20V = 30V
It can get way more complicated than this with a microcontroller and current measurement to calculate exactly what the resistance value is and what the battery voltage is but this are unnecessary complications just to say that it can be done.

Higher voltage output pulses are possible but not a steady voltage.

How about an LTspice simulation of one of the answers ?

Here's a simulation. A capacitor is first connected in series with the supply and the load, which charges it up. It is then connected the other way round, negative plate to V1 and positive to the output. The capacitor first discharges, adding its voltage to V1, before charging in in the opposite direction. Higher voltages are possible by connecting more capacitors in parallel and then in series for the discharge cycle.

This circuit isn't practical application. It's just a theoretical demonstration. It's possible to use solid state relays connected to a microcontroller for the timing. The microcontroller could be powered via another capacitor which is charged in series with the load resistor.

[electrodacus]

A) Is it possible for V2 to be a constant 30V?  No
B) Is it possible for V2 to peak to 30V multiple times while V2 never drops below 5V ?  Yes

So do you not agree with one of my answers ? Or with both ?

Now that you have stated a somewhat clear question who has disagreed with you? No-one! So why immediately ask if every poster agrees/disagrees?

Just the comment before yours Andy Chee asked for a LTspice simulation as proof for those answers.
Should I understand you do not disagree with my answers to those two questions?
As there will be people asking the opposite of what you are asking.

[electrodacus]

I'm more used to having the signal flow drawn from left to right, but whatever.

Me too. Power, voltage, signal flow from left to right and from top to bottom. I often redraw schematics that way because it helps me analyze and understand the circuit.

When I reverse engineer a circuit I start out with a schematic which resembles the PCB but I rearrange it in steps until it is easier to conceptualize.

I agree and sorry for having the diagrams drawn in a non standard way.  I was thinking that is a simple enough diagram that it will not affect anyone's ability to understand.

[electrodacus]

The acceptable way to change your opinion is:

• add a new post indicating your new opinion
• optionally changing the early post, using strikethrough to indicate what you no longer wish other people to consider, and adding "EDIT: ..." to show your new opinion.

Doing that makes you appear to be thoughtful and considerate.

"Silently" changing the early post makes you look like an insecure troll.

I did not changed my opinion. I made the original post more clear and easier to answer by adding an example of what can be inside the green box and asked two questions that can be answer with a simple Yes or No.

[coromonadalix]

again  an useless thread  wholl endup shutted down ... pffffffffff


and seeing your past threads    "electrodacus"   you seem to love making some ruckus 

im not a mod, but you'd be on a warning

[electrodacus]

I fully understand that context. I knew what this was about from the very first post in the thread, since we've been here before.

But I want electrodacus to provide a direct quote where someone said the DC-DC converter could provide a continuous step up in voltage without a third electrical connection. Otherwise he is just being disingenuous and misrepresenting people.

Because I really don't believe anyone on this forum would be likely to say that about the "DC-DC converter" picture in the first post.

I will try to make a search but it was over a year ago and it will be some work to search trough all those comments.
So should I understand you agree with my answers to both of those questions A) and B)  ?

[coromonadalix]

i agree with nothing, you seriously need to relearn electronics / applications  and a few other things, instead of starting thread and sucking life out of many members here

all you answers can be found elsewhere

its a derailing thread  thats all       



im beginning to wonder if some people want click counts or post / thread counts   the way i see things

in the fpga or micro processor thread  one guy  started 4 thread of the same part with slight differences, and before it would have been blocked,mad a complaint and its still going   

[electrodacus]

Here's a simulation. A capacitor is first connected in series with the supply and the load, which charges it up. It is then connected the other way round, negative plate to V1 and positive to the output. The capacitor first discharges, adding its voltage to V1, before charging in in the opposite direction. Higher voltages are possible by connecting more capacitors in parallel and then in series for the discharge cycle.

This circuit isn't practical application. It's just a theoretical demonstration. It's possible to use solid state relays connected to a microcontroller for the timing. The microcontroller could be powered via another capacitor which is charged in series with the load resistor.

Thanks for doing the simulation and thanks for answering my questions clearly.
I think there are at least 2 or 3 people excluding me that agree with you so I'm looking for those that did not provided a straight answer but doubted that is the case some asking for simulation proof.
 

[electrodacus]

again  an useless thread  wholl endup shutted down ... pffffffffff


and seeing your past threads    "electrodacus"   you seem to love making some ruckus 

im not a mod, but you'd be on a warning

Why will the thread be "shutted down" ?
Not quite sure why you think I "love making some ruckus".
This is a question about an electrical circuit with floating GND.
I do expect much more people here know the correct answers to this but it will not be all.
For those that did not know the answer to this even if they do not comment just read this it is a learning experience.
I do not think I said anything controversial for most people. 

[electrodacus]

i agree with nothing, you seriously need to relearn electronics / applications  and a few other things, instead of starting thread and sucking life out of many members here

I do not understand.
What do you agree or disagree with ?
I'm guessing you are refereeing to me when you say I need to relearn electronics. That sounds like you disagree with my answers to those two questions. Or maybe it is with something else I said ?

It is hard for me to understand why anyone will think I'm a troll or I enjoy this. I do not.

[Zero999]

Thanks for doing the simulation and thanks for answering my questions clearly.
I think there are at least 2 or 3 people excluding me that agree with you so I'm looking for those that did not provided a straight answer but doubted that is the case some asking for simulation proof.

No one said that the output voltage can never exceed the input, just that the output voltage can't be continuous. The original post was poorly worded and the fact you appear to have gone back and changed it hasn't done you any favours.

[PlainName]

I did not changed my opinion.

Then why are you here making yet another thread on the same thing? You're not here to learn; you are here solely to get everyone else to agree with your erroneous but fixed opinion. You won't stop unless every last one says "Oh yes, you're right".

That's it. The thread serves no other purpose except for you to spout off and get agreement that you are right. But you are wrong, and since you will never accept that you will just forever be creating this very same thread again. And again. And again.

The only reason you're doing it here, now, is because you've been banned from every other respectable forum for doing the exact same thing there.

[electrodacus]

No one said that the output voltage can never exceed the input, just that the output voltage can't be continuous. The original post was poorly worded and the fact you appear to have gone back and changed it hasn't done you any favours.

I changed it because it was poorly worded based on the feedback from others. Sorry if you think is still poorly worded. Can you point out what part so I can make it more clear ?