Body
Hi Sven,
Here is an old answer not yet shown by Yahoo. But it looks like you have solved some of the problem already.
Hi Sven,
The current charging the 10uF capacitor enters from the top going through the capacitor and the first and second exit diodes with the variac inductor between them. When the 10uF capacitor reach the peak voltage for triggering the SCR there is still some current through the variac inductor. This current continues until the variac has fully discharged its magnetic stored energy. As long as this current (red) runs the SCR can't shut off even though the 10uF capacitor may have totally discharged to 0V. I.e. the green current has ended.
I thought the variac was for limiting the discharge current from the 10uF capacitor and then had to be placed in the green current path like between the anode of the SCR and the output transformer.
If placing the variac at the center tap of the output transformer one inductor (variac) limits the current from both SCR halves. Perhaps the output transformer should just have the proper size to be able to not saturate from the amount of energy wanted. Or alternatively the 10uF capacitor has to be discharged at a lower voltage to not saturate the output transformer being used. This limits the power to the level the transformer can take.
"Or you may install on the variacs in parallel capacitors that absorb the energy for a moment. I make a drawing of the Buck plug circuit with any meaningful improvements."
Putting a capacitor in parallel with the inductor makes it an-LC tank which stores the energy. It oscillates until the energy is removed or dissipated. I don't think this will solve the problem.
Regards
Ole
---In [email protected], <s.friedrich@...> wrote :
Hello Ole,
I thought so too. At low inductances, the problem does not occur because the energy does not seem to be stored that much. You could increase the load as this reduces the energy that can flow back
I seem to have a time problem, the energy would have to be stored only between so that the discharge capacitor can fall to the cut-off voltage.
You could use free-wheeling diodes directly at the transformer then the current recirculating diodes I think about.
Or you may install on the variacs in parallel capacitors that absorb the energy for a moment. I make a drawing of the Buck plug circuit with any meaningful improvements.
regards
Sven