Graham Gunderson's Energy conference presentation Most impressive and mysterious

[EMJunkie]

member Smudge has done a ruff analysis from the Photos

respectfully

Chet K

Most awesome work Smudge!!!

Thanks Chet for posting this!!!

This does however present some confusion for me.

Smudge says:

Note that during this period there is no load on the secondary to consume power.

in the Context:

The saturation knee has been set to coincide with the current level at the kink in the current waveform. If the core material were linear the ratio of flux to current either side of this line would be a constant value, but clearly this is not the case. It seems that above that line the material has lower mu, has moved into saturation, while below that line the material has higher mu, below saturation. This now offers an interesting possibility. In the high mu region, at high inductance, the system has produced current at virtually zero power loss because of the phase quadrature.

then Smudge goes on to say:

This shows the output current waveform and the load switch region. I have to admit to being completely baffled by this waveform since it is showing current outside the load connected region.

Being that there is a very good chance that the Mosfets have internal Diodes, and if the Circuit on the Output is a correct implimentation of how Graham is using the Mosfets as a Syncronous Rectification, then we should see conduction in both directions of the Cycle as is shown, only if the Mosfets are on.

This we do see. The Mosfets are switched off, 244.125 Degrees,  then on again abruptly at approximately 248.625 Degrees on the Output Current wave form.

If there was no Conduction of the Output Coils, then we should see Zero Output Current flow on the Scope where the Output Coils are "Not Connected" (Mosfets are Off...) Similar to the half bridge retification image below.

We see Output Current flowing in the Red (Positive Current) and Black (Negative Current) portions of the wave form, there is not any Zero, non conduction periods, except for the Turn Off and Turn On again.

Someone please explain where I have this wrong!!!

   Chris Sykes
       hyiq.org

[EMJunkie]

What if, there appears to be no load, but that the Load really is connected...

There appears to be no load, because there is no reflected Magnetic Field back on the Primary Coil... Lenz's Law is not affecting the Input... Thus the Reactive Nature of the Input is not Damped...

After all, Power is the product of Voltage x Current, anytime there is Current and Voltage present, DC especially, not so much AC Reactive, depending on the Phase Angle, there is an Active Power component...

   Chris Sykes
       hyiq.org

[Reiyuki]

What if, there appears to be no load, but that the Load really is connected...

There appears to be no load, because there is no reflected Magnetic Field back on the Primary Coil... Lenz's Law is not affecting the Input... Thus the Reactive Nature of the Input is not Damped...

After all, Power is the product of Voltage x Current, anytime there is Current and Voltage present, DC especially, not so much AC Reactive, depending on the Phase Angle, there is an Active Power component...

   Chris Sykes
       hyiq.org

  It is not switched that way.  In a synchronous rectifier, the way he has it set up, the two coils are being alternately shorted, not shorted against each-together.

Reactive power and phase-angle is likely indeed important, but as you can see in the device, there are a LOT of factors at play (multipl permeabilities, unique driving circuitry, unique interrupted load, and an input ferrite saturated 'to the knee').  If any of these factors were not critical, it is likely they would not be in the final product he had presented us.

[gotoluc]

I've been playing with this a little and it looks like I can get a similar wave form with just using 36vdc chopped by a mosfet switch around 21.7kHz with a 33% duty cycle to a primary coil which has a 0.002uf capacitor connected in parallel tuned to resonance (21.7kHz).


Yellow is a x100 Voltage probe across primary coil, Blue is a Tektronic P6021 current probe on negative of primary coil, Red is the product (math) of V x I and Purple is the DC output of the secondary (after FWBR to a 27,000uf cap with 20 Ohm load).


Luc

[TinselKoala]

It would be interesting to know the actual value of the Purple trace. Its baseline is offset below the display area. Does the Measurement of 4.07 Vrms represent the actual value or just what is shown on the screen, from the bottom graticule marker to the trace itself? The question mark indicates unreliable measurement, doesn't it?

Nice work, as usual, anyhow.