Still left to solve is the current limit
And probably edit of the circuit above to limit the output to 5v max, thats safer than a zener

 

Do you now see that i was asking for a simple circuit?
57 comments in this tread about ewrything else than inventing a circuit and mostly talking about a super advanced expencive task to solve, i just dont get it, we are mostly in lockdown and have alot of free time, for someone that understand circuit design it would take 5min to solve this

I'm not wasting my time on something that's unlikely to work (from trial and error experience) as you think and I'm not in lockdown here. I'm glad you have the circuit and I'm sure you will enjoy the learning experience with it.

 

i got some help elsewhere, i dont know why i write this to this forum, maybe to help other people out witch is looking for the same.

the first problem is to stepdown the battery voltage to a usable voltage.
its done with 9Mohm in series and 1Mohm to ground.
voltage wil be 24 to 27v at each extreme end

second problem is to get 0-5v based on 5v difference on the battery voltage.
solved by this circuit:
View attachment 204068

input at the top left wil be the 24 - 27v
input at the bottom left wil be a regulated adjustable voltage course 24-27v

this circuit wil amplify the difference between this 2 voltages so for example
the battery sit at 241v = 24,1v at the input
the regulated voltage is 24v
then there is 0,1v difference

the output wil be amplified to 1v

this 1v wil be feeding a 0-5v pwm circuit and pwm wil be on 20% duty

i wil order some parts and test it out

the next problem wil be the potential of 30v being on the 0-5v if each if the inputs are at max apart situation.
the output of the 0-5v circuit wil be a current limiting resistor, then a 5v zener to ground to make sure all voltages over 5v is pulled down to 5v.

then the next is current shunt, the current shunt wil be a regular resistor style measuring mv voltage drop across the resistor.
this circuit also need to pull down the 0-5v signal gradually if the current is more than setpoint

afther that its only igbt driver circuit and pwm circuit left to find but thats avalible

then test it all out

Cool, glad you got the circuit you need. That's more or less what I'd offered to attempt, but I haven't had time yet. Since you've got it now, I won't bother with it.

Best of luck with it. I hope it does what you want, although I'll admit to being a little skeptical. I know many of the people commenting here haven't quite understood what you were going for, but there were also a few who did, and they were also still skeptical (and they're people whose opinions I trust based on years of experience with them on this forum.) Those comments aside, good luck and have fun!

 

https://www.analog.com/media/en/tec...ata-sheets/LTC6992-1-6992-2-6992-3-6992-4.pdf

 

Do you now see that i was asking for a simple circuit?
57 comments in this tread about ewrything else than inventing a circuit and mostly talking about a super advanced expencive task to solve, i just dont get it, we are mostly in lockdown and have alot of free time, for someone that understand circuit design it would take 5min to solve this

Not all here are of the same mind. I offered to look into developing a circuit.

 

Not all here are of the same mind. I offered to look into developing a circuit.

Yes and thnks for that, if you have a current limit citcuit in your pocked i would be happy to get that.

Look at the drawing i posted witch i draw with a pen, there you can see my ideafor current limit,
Some way to gradually pull down the 0-5v signal according current passing the current shunt, adjustable by pot
Offcorse my drawing do not work but it should be possible to do it that way

 

https://www.analog.com/media/en/tec...ata-sheets/LTC6992-1-6992-2-6992-3-6992-4.pdf

thanks, i was looking for about 3 to 15khz and 0-5v controlvoltage

do you know of some ic that work wit that?
or is a 555 timer circuit the best way to go?

 

Cool, glad you got the circuit you need. That's more or less what I'd offered to attempt, but I haven't had time yet. Since you've got it now, I won't bother with it.

Best of luck with it. I hope it does what you want, although I'll admit to being a little skeptical. I know many of the people commenting here haven't quite understood what you were going for, but there were also a few who did, and they were also still skeptical (and they're people whose opinions I trust based on years of experience with them on this forum.) Those comments aside, good luck and have fun!

thanks to thaughts, i do not have circuit simulator so if someone could test the voltage devider and 0-5v conversion circuit it would be great

 

Here is a basic PWM controller. See what you think.
This is for 24vdc but for 240vdc we would use more than one transistor as shown as Q1,Q2.
The "REF" would probably be a potentiometer adjustment to adjust the current limit.

 

57 comments in this tread about ewrything else than inventing a circuit and mostly talking about a super advanced expencive task to solve,

And do you think that if this was/is a real problem in the real world it wouldn't already be available?

 

Here is a basic PWM controller. See what you think.
This is for 24vdc but for 240vdc we would use more than one transistor as shown as Q1,Q2.
The "REF" would probably be a potentiometer adjustment to adjust the current limit.

View attachment 204106

I was thinking capacitors on the output of the igbt so the output would be close to dc, this circuit you posted would still work i think but how to use the comperator Q1 Q2 to gradually pull down the 0-5v signal on my circuit?

Or is it compable with 0-5v already? Just need to use some circuit to make the opamp output 0-5v acording to current??

 

I was thinking capacitors on the output of the igbt so the output would be close to dc, this circuit you posted would still work i think but how to use the comperator Q1 Q2 to gradually pull down the 0-5v signal on my circuit?

Or is it compable with 0-5v already? Just need to use some circuit to make the opamp output 0-5v acording to current??

Yes that was the basic circuit for current limit. The circuit would need additional parts to work between 240v and 245v only. So the final circuit will be almost like an Li-ion charger except it will be loading not charging.
It would then operate on voltage with current limit.

Does that sound right now?

 

And do you think that if this was/is a real problem in the real world it wouldn't already be available?

It is available today as a digital subroutine in diversion controllers but no commercial designer would do it with what turns out to be a more complex and difficult to calibrate ,tune, control analog circuit as a substitute for a $1 controller.
http://www.microhydropower.com/wp-content/uploads/2015/03/Diversion-Battery-Control.pdf

 

Yes that was the basic circuit for current limit. The circuit would need additional parts to work between 240v and 245v only. So the final circuit will be almost like an Li-ion charger except it will be loading not charging.
It would then operate on voltage with current limit.

Does that sound right now?

Ummm first voltage is adjustable 240-265 for the start voltage, 100% pwm is 5v higher.

By 240v you mean at the shunt?

The voltage difference across the shunt wil be milivolts, the same as the 0-5v circuit.

So is it enough to use a x10 voltage devider on the potentiometer ground and to the shunt input?
Then the opamp wil compare the 2 voltages and figure the difference.

Howewer i want to hold the 0-5 signal at the perticular voltage witch equal to the current set point, how do that part work ?

I was thinking when the current become higher than setpoint the opamp start to gradually pull down the 0-5v until the current become the same as setpoint and hold the 0-5v at that level

and i explain like a mess as usuale.

what i try to say is that i want to shop/cut the 0-5 voltage at the level witch hold the current i want

 

Ummm first voltage is adjustable 240-265 for the start voltage, 100% pwm is 5v higher.

By 240v you mean at the shunt?

The voltage difference across the shunt wil be milivolts, the same as the 0-5v circuit.

So is it enough to use a x10 voltage devider on the potentiometer ground and to the shunt input?
Then the opamp wil compare the 2 voltages and figure the difference.

Howewer i want to hold the 0-5 signal at the perticular voltage witch equal to the current set point, how do that part work ?

I was thinking when the current become higher than setpoint the opamp start to gradually pull down the 0-5v until the current become the same as setpoint and hold the 0-5v at that level

Check this. Note the similarity to a battery charger.
Ref2 is to adjust voltage set point Ref1 to adjust current limit.
Yes pots will be used for adjustments.

 

maybe a current shunt is not needed at all.
all i want is to prevent the current to be larger than setpoint.
current is directly connected to pwm duty sycle

so if i limit the 0-5 v to for example 2.5v that means only 50% duty sycle wil happen and offcorse the current wil also be lower.
i found a simple clipper circuit here wil that work?:

https://www.brainkart.com/article/Clipper-and-clipper-using-Operational-Amplifier_36014/

 

Check this. Note the similarity to a battery charger.
Ref2 is to adjust voltage set point Ref1 to adjust current limit.
Yes pots will be used for adjustments.

View attachment 204146

that was a nice simple circuit would work fine i think, replace transistor Q2 with igbt, and aditional circuits to work with 240v

 

that was a nice simple circuit would work fine i think, replace transistor Q2 with igbt, and aditional circuits to work with 240v

Next version...

 

Next version...

View attachment 204357

great work, thanks
is vcc +30v?

and what is the values of the resistors and capacitors?

 

Next version...

View attachment 204357

To get 5v batteryvoltage 0-100%duty, the sawtooth waveneed to have 5v between minimum and maximum right?