Proteus: Problem with Output Capacitor

[pagefault]

Hello everyone, this is my first message in the forum I'm also starting with circuit simulations. I'm simulating this simple circuit using Proteus 8...



...and I get the following message:



But if I disconnect the capacitor the problem dissapears. I assume I have convergency problems, but I cannot understand why.

Thanks in advance for your answers =)

 

[Easyrider83]

There are no ground on secondary side.

 

[pagefault]

Thanks for your answer. That actually prevents the error messages from appearing but I think that I'm also losing the isolation between the input and the output, is there a way to specify that their are different grounds? Thanks again.

 

[KlausST]

Hi,

it is a (known) simulation problem.
It doesn´t need to be low ohmic. Often a 100M Ohms resistor to ground the secondary side helps.

BTW: I don´t think it´s a good idea to switch the capacitor with unknown high currents. A current limiting resistor or an inductor helps to keep switching currents low.

Klaus

 

[Easyrider83]

Thanks for your answer. That actually prevents the error messages from appearing but I think that I'm also losing the isolation between the input and the output, is there a way to specify that their are different grounds? Thanks again.

You are worring about being shoked by virtual electricity? :laugh:
All relevant measurements have to use their own grounds.

 

[BradtheRad]

Try adding a high ohm resistor across the diode. I believe the simulator creates oscillations erroneously, due to action of neighboring LCD. The diode starts to turn off below its threshold V, but the inductor wants to produce current regardless, so it turns the diode on again.

 

[pagefault]

Hi everyone, I appreciate all your answer, I've been trying the solutions you propose but I still can't figure out why this is happening.

The same happens to me in every simple circuit I try to implement, like the following:



The circuit seems to be working fine, but when I add the ground to the secondary side and hit the run button, I get error due to CPU overload (I also try adding a high ohm resistor as KlausST suggested but I got the same error).

Can anyone tell me why this is happening?

Thanks in advance.

 

[KlausST]

Hi,

now there´s a new situation.

Add a 1000k resistor from secondary capacitor negative side to GND
Add a 1000k resistor in parallel to D2.

Show us the updated schematic.

Tell us what happens.


Klaus

 

[pagefault]

Hi,

now there´s a new situation.

Add a 1000k resistor from secondary capacitor negative side to GND
Add a 1000k resistor in parallel to D2.

Show us the updated schematic.

Tell us what happens.


Klaus

Hi Klaus, thanks for taking your time to give me a new answer.

I updated the circuit in the way you suggested and it worked perfect :thumbsup:


Now I've been trying to understand what's going on, but I stil didn't get it :roll:

 

[BradtheRad]

Take a look at my Youtube video below. It's an animated simulation, which depicts current flow in this type of power supply. How the capacitor charges, powers the load, etc.

Full-wave diode bridge power supply (Animated):