View Single Post
Old 07-13-2016, 08:35 PM
Reiyuki's Avatar
Reiyuki Reiyuki is offline
Join Date: Mar 2009
Posts: 51
Originally Posted by k4zep View Post
So one half of the C is on the top side where the primary coils is wound (high Perm) and biased with the magnets the move i'ts knee to where the pulsed waveform can probably kick it over and under that point and the as you call it "Push-Pull-Sleep" or "Forward-Reverse-Off providing that big kick back pulse as you said should be a no brainer to reproduce with a minimum of parts when resonant frequency of the input coil is known.
Yes. I like the 'forward-reverse-off' description better as well and will use that term from now on.
He said on this setup the effect would show up in a fairly wide band, 20-50kcps.

Then the bottom one half is a lower perm material. Do you remember if it was also resonant, I doubt it due to the synchronous rectification?
From the photos I have, the only output connections I see are to those massive electrolytic caps on the left, so you're probably right about that.

It would appear to be a higher "C" circuit, that is less inductance, more Cap. if it is resonant. The most important thing here is he has found a system that appears to work and is open about it!!!!!
The input has HV capacitors on it. It looks vague like a ZVS like in a Tesla Coil, except the FETs are driven manually.

Output circuit is a synchronous rectifier that is normally closed and is opened just before the push/pull transition above. I wonder if this allows a sort of reset in the residule field by removing the load for a short time.
Or, maybe it reflects the flux back and the high perm ferrite sucks it up and gives it back the rest of the cycle? IE: using the field, then returning it. Graham says he doesn't really know either. Since it's 20-50khz, magnetostrictive effects might also be responsible for it.

If and when you get part numbers of those H bridge drivers it would be a great help. As I was not there, Frequency, current etc. into the input coil would be great information. One thing I question is when the input power decreased over time but the output remained the same, any thoughts as to what was happening?

C2M0025120 (1200v with VERY low ON resistance and VERY fast switching).
Amazing carbide MOSFETs. Fragile though, so you'll want lots of protection on the gate to keep the magic smoke inside. Look for the HV russian schematics or Solid State Tesla Coil guys for ways to drive and protect the FETs.

Input: the push/pull is tuned resonant and the OU effects manifests around 20-50khz. It is an H bridge running at 200-300v with a big inductor in series so it becomes a constant current driver.

The total output was always around 5-10w, and COP would vary depending on what point you triggered the interrupter.

Imagine the entire cycle as 360deg, and lets say the Push/Pull pushes from 0-120 and pulls from 120-240.

In that example, the output interrupt occurs around 100-140deg and lasts 100nS-2uS (circuit reengaged just after the pulse peaks, which is ~1200v or as far as the FETs will safely handle).
If I understand him correct, varying the phase would cause changes the COP and the total outputs, so changing the phase interrupt would cause the I/O to look something like this:
100deg 5w in 4w out
110deg 4w in 8w out
120deg 3w in 6w out
130deg 0w in 4w out
140deg -1w in, 3w out

IIRC on his demo, he was interrupting just before 120deg, resulting in ~3.5w in and ~8.5w out.

We're still not sure what components of his system are critical and which are superfluous. It might be possible that the entire thing could be replicated with a single magnet and a split-core Joule Thief that is driven in this unique way. I have not seen anyone playing with a combination of interrupted outputs and PWM driven inputs.

Hope that answers everything, feel free to ask anything else. I may not have a working system but at least I documented one that did
Reply With Quote