Kapanadze Cousin - DALLY FREE ENERGY

[itsu]

Itsu, what kind of shottky diodes (D3,D4) are you using to your setup?

I found some speaker wire 2X2.5mm and i ordered it. I hope this time it will fit across the circumference of my yoke as when i tried to wound it before, i had used two separate 2,5mm cables with thick insulation and couldn't fit.

For C3,C4 i will use normal electrolytic caps. Can they handle the kickback?

Hi Jeg,

thats an old diagram from the beginning of this thread.
Verpies recently showed a newer one using MOSFET drivers instead of transistors, look for it, but basically its the same.

I started with BAT46 (100V) schottky diodes as D3/4, but now i have D12G60C's in.

You can always use thinner "return" wire for your primaries, it should then fit a fairly large yoke.

I have 2x 100uF / 250V elco's as C3/4 and they are "stiffened" by 2x 100nF / 630V Poly caps parallel to them.

Itsu

 

[Jeg]

Hi Jeg,

thats an old diagram from the beginning of this thread.
Verpies recently showed a newer one using MOSFET drivers instead of transistors, look for it, but basically its the same.

I started with BAT46 (100V) schottky diodes as D3/4, but now i have D12G60C's in.

You can always use thinner "return" wire for your primaries, it should then fit a fairly large yoke.

I have 2x 100uF / 250V elco's as C3/4 and they are "stiffened" by 2x 100nF / 630V Poly caps parallel to them.

Itsu

Thanks a lot Itsu
I use Acula's driver with an ir2110 for driving my mosfets. It has not any 'enable' pins, so i guess that this topology fits more to my setup.

[Dog-One]

I use Acula's driver with an ir2110 for driving my mosfets. It has not any 'enable' pins, so i guess that this topology fits more to my setup.

I'm pretty sure verpies mentioned using the enable pin on the gate drivers is just a protection circuit.  I don't think it is mandatory for proper loss-less clamp operation.  You just need to be sure whatever push-pull signal generation you use guarantees high-side and low-side will never be active at the same time.  I could be wrong, but I think this portion of the circuit only kicks-in when you are running on the ragged edge of 50% duty cycle.  If you have a fixed dead-time in your push-pull signal generation, I don't think it's needed.  Verpies can probably clarify.  Or Itsu maybe can connect the scope to his circuit and see if there is ever a point when the disable is active and the input signal is also active, i.e. overlap.

[verpies]

I'm pretty sure verpies mentioned using the enable pin on the gate drivers is just a protection circuit.  I don't think it is mandatory for proper loss-less clamp operation.  You just need to be sure whatever push-pull signal generation you use guarantees high-side and low-side will never be active at the same time.  I could be wrong...

You are correct. 
It's just a safety feature to prevent both MOSFETs from being ON at the same time.

[verpies]

For C3,C4 i will use normal electrolytic caps. Can they handle the kickback?

Almost. Ideally these electrolytic caps should be large and have a smaller pulse capacitors connected in parallel, e.g. 1uF polypropylene film caps.
This is because electrolytic caps have high impedance at high frequencies, unlike film caps.

Itsu, what kind of shottky diodes (D3,D4) are you using to your setup?

These diodes should be able to withstand in reverse at least 2x the voltage applied to the center tap of the primary winding. 
This is the same voltage as the smallest MOSFET's max blocking voltage, that you can get away with.

These diodes must be fast.  The 1N4xxx series diodes will not cut the mustard.

These diodes do not have to be Schottky ...but Schottky diodes are fast and have a low forward voltage drop (V_F), so they also minimize V_F*I losses.

Thats an old diagram from the beginning of this thread.
Verpies recently showed a newer one using MOSFET drivers instead of transistors, look for it, but basically its the same.

Yes. The newer one is here.