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Author Topic: Parametric Charging  (Read 38092 times)
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  Interesting question.   18" diameter is huge...

 I wonder if you (PM) could show us a photo of your coil or inductor, with a ruler or something to show the size?

Sure, here is a pix of the coils used thus far.  The air cores are used in the parametric circuit and the smaller ferrite cored inductor is used in the lower frequency resonant charging circuits.

Pm
   
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For those that have some time to tinker, and based on PM's research, I submit this first draft of a stand alone looped device with self oscillating feature.

I have not got the time to test it on the bench but am sure it can be made to self oscillate if the coupled inductor gain is sufficient.

The IXD601 device data sheet states a max logic input current of  only 10 uA,so the input drive should not load the output coil very much.

Whether it will work without the starter circuit as a self powered unit is another matter.

Ion,

Thanks for the looping circuit.  The newer resonant or more accurately off-resonant charging circuit would be an excellent candidate for attempted self running if the switching circuitry can be made efficient enough.

Pm
   
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All,

This is a test of the circuit shown in post #288 running continuously with the frequency adjusted to 60.8kHz which then produces a voltage across loaded C1 that is slightly greater than the 40v dc supply voltage.

In the scope pix, we see the output voltage of 40.64v across C1 with a 7.451k ohm load resulting in a pout = 40.64^2/7.451e3 = 221.7mw.  The pin is seen to be 195.5mw for an apparent COP = 221.7/195.5 = 1.13.  This may be enough gain to achieve self looping but I'm not sure if the Ixd60x series is efficient enough though.

Also to clarify, the circuit is not operating at resonance but rather off-resonance to a higher than resonance frequency or inductive side.  This is evidenced by the input current lag in regards to the input pulse seen on CH1(yel).  It will also operate on the lower than resonance frequency or capacitive side but at a lower efficiency.  At resonance, it is very inefficient.

Pm
   
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Sure, here is a pix of the coils used thus far.  The air cores are used in the parametric circuit and the smaller ferrite cored inductor is used in the lower frequency resonant charging circuits.

Pm
Thanks for the pix of the coils you have used - very nice!
   
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All,

This is the same test run in post #302 but now operating at 23.6kHz or the low side off-resonance.  Contrary to what I stated previously, this is actually more efficient!

In the scope pix we see the voltage across C1 with a 7.451k load is 40.27v resulting in a pout = 40.27^2/7.451e3 = 217.6mw.  Pin is 187.1mw for a COP = 217.6/187.1 = 1.16.

Based on the current waveform, this may yet be another operating mode!

Pm

Edit:  IMO at these low operating frequencies, the Rigol scopes should easily be able to accurately measure a 100ms charge sweep.
   
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  This is remarkable - running at just 23.6 kHz. 

   Just to double-check, in these runs - are you using the smaller ferrite-cored inductor?

Thanks again!
   
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  This is remarkable - running at just 23.6 kHz. 

   Just to double-check, in these runs - are you using the smaller ferrite-cored inductor?

Thanks again!

Yes, these low frequency tests use a 1/4" square ferrite E core with a 0.020" gap as they must operate as linearly as possible.  IMO, there is no limit to the lower frequency that will work except possibly ELFs.

Attached is an example of lower frequency with a charge sweep and continuous run of a low off-resonance (LOR) circuit at 16.5kHz with L1 = 2.46mH, C1 = 3.94uf, and C2 = .01uf.

The first pix is the charge sweep measured over 100ms showing the C1 voltages with the A and B cursors.  The energy differential is (58.28^2-43.03^2) * 3.94e-6/2 = 3.044mJ which equates to a pout = 3.044e-3/99e-3 = 30.7mw.  The input power is seen to be 13.1mw resulting in an apparent COP = 30.7/13.1 = 2.34.

With the average voltage across C1 being 52.91v, we can now calculate the required load resistor RL = 52.91^2/30.7e-3 = 91.2k ohm.

The next scope pix shows the continuous run with a 90.7k (closest value) load resistor at 16.5kHz.  The output voltage across C1 with the load is 53.30v so pout = 53.3^2/90.7e3 = 31.3mw.  The pin is 12.21mw so the apparent COP = 31.3/12.21 = 2.56.  Again note the correlation between the sweep and continuous data.

The downside to this mode is the low power which would be improved by higher operating voltages but perhaps there is a better way.....?

Regards,
Pm 

   
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I'll be doing at least 1 replication, but, as these things go, will likely build half a dozen once I see one do something  O0

There are a bunch of questions though.
Is the 40V input based on raising the Pin and Pout to levels that can be more easily discerned as > COP 1 ?
Could some type of high secondary turns Joule Thief achieve similar end results, with a starting voltage much lower and bumping it to the 40V ?
A similar question for the looping thoughts.
Which components dictate the resonant frequency of the circuit ?
If it's the central WIMA cap bank, what happens if another brand or value of cap is used ?
Can these IXYS MOSFET drivers be used ? https://www.ebay.com/i/162811331846
Otherwise, the type that Itsu has unfortunately witnessed burning are about $7 each at the cheapest.
Is a MOSFET driver needed ?..apologies for my lack of knowledge on this section, if it's merely Gate drive then surely there are passive routes rather than spendy chips.
There was talk of close coupling within the coil windings, but i'm seeing large single winding crystal radio type coils in pics (for want of better wording). Could the coils be explained ?

Many thanks for any answers, have read all 13 pages but those keep niggling.


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I'll be doing at least 1 replication, but, as these things go, will likely build half a dozen once I see one do something  O0

There are a bunch of questions though.
Is the 40V input based on raising the Pin and Pout to levels that can be more easily discerned as > COP 1 ?

No, the >1 COPs will be seen at lower voltage levels if the circuit is working properly.  I run with 40v dc supply because it yields the highest power output which makes the scope measurements more accurate IMO.  The Ixys drivers are actually rated with a max of 35v dc so they a little stressed at this level especially at the higher frequencies.

Quote
Could some type of high secondary turns Joule Thief achieve similar end results, with a starting voltage much lower and bumping it to the 40V ?

I don't see why not as long as it produces a square wave with reasonably fast rise and fall times.  Sine waves will not work.

Quote
A similar question for the looping thoughts.
Which components dictate the resonant frequency of the circuit ?
If it's the central WIMA cap bank, what happens if another brand or value of cap is used ?

In the resonant charging circuit it is L1 and C2 that determine the resonant frequency.  L1 should be a linear inductor and C2 can be any good quality film cap.  The storage cap C1 can be any good quality capacitor and I just prefer the film caps over 'lytics.

Quote
Can these IXYS MOSFET drivers be used ? https://www.ebay.com/i/162811331846
Otherwise, the type that Itsu has unfortunately witnessed burning are about $7 each at the cheapest.

They have output fault protection which might get tripped when the circuits attempt to supply energy back to the power supply but otherwise they should work just fine.

Quote
Is a MOSFET driver needed ?..apologies for my lack of knowledge on this section, if it's merely Gate drive then surely there are passive routes rather than spendy chips.
There was talk of close coupling within the coil windings, but i'm seeing large single winding crystal radio type coils in pics (for want of better wording). Could the coils be explained ?

Actually any type of mosfet gate drive will work and I hope to do more investigating into this to allow looping if possible.  At present there is only one inductor used but there could be many possible combinations of windings that would step up the drive voltage, provide full wave operation, and have L1 integrated in the leakage inductance.  I don't think this is needed at this point to attempt looping with the LOF circuit, just efficient switching of the input pulses.

Pm

Quote
Many thanks for any answers, have read all 13 pages but those keep niggling.
   
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All,

It seems that power output is not a problem with the LOR (low frequency off-resonance) mode it is just a matter of give and take.  The lower the power out the higher the COP and vice-versa.

The first scope pix show the same circuit as previously shown except with a load of 3.71k ohm and operating at 16.3kHz with the supply at 40vdc.  CH3(pnk) shows the dc voltage feeding the circuitry for comparison to the CH3(blu) showing the voltage across C1 with load.  CH2 should be reading in mean rather than rms but with the dc voltage it is the same so we see 40.44v across the 3.71k load resistor for a pout = 40.44^2/3.71e3 = 441mw.  The pin seen in the Math channel is 418mw for an apparent COP = 441/418 = 1.055.  If we increase the load resistance, pout will decrease and the COP will increase so it is a matter of one's choice.

The highest apparent COP that can be obtained with the LOR is at 1/2 the resonant frequency or fo/2.  The resonant frequency is determined by L1 and C2 so in this case fo = 1/((2.46e-3 * .01e-6)^.5 *2*3.14) = 32.08kHz.  So, fo/2 = 16.04kHz.

The second scope pix shows the results of the identical circuit running at 16.0kHz with a 90.7k load at 40vdc.  The output voltage is 40.0vdc so pout = 40^2/90.7e3 = 17.6mw.  The input is seen to be -3.115mw however, due to the very small amount of current being measured during the pulse "on" time, the power measured by the Math channel is rather ambiguous so it will vary between what is seen and ~+2.0mw.  It still equates to a rather high apparent COP.

The power can also be increased for a given load by increasing the frequency towards resonance but the output voltage across C1 will also increase.  These tests were run with the loaded output across C1 to be slightly higher than the power supply voltage. 

Also noteworthy is that the output voltage self regulates quite well in the LOR with changes in load but of course there are limits.

Regards,
Pm 
   
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Many thanks for the prompt answers Pm :)

I think i'm best ordering at least one of the spendier IXYS chips, but also to order the much cheaper versions as well.
As a side note, i've used IXYS 6V 22mA solar panels extensively over the past few years and know them to be a consistent high quality manufacturer.



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ʎɐqǝ from pɹɐoqʎǝʞ a ʎnq ɹǝʌǝu
   
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  PM:  "The second scope pix shows the results of the identical circuit running at 16.0kHz with a 90.7k load at 40vdc.  The output voltage is 40.0vdc so pout = 40^2/90.7e3 = 17.6mw.  The input is seen to be -3.115mw however, due to the very small amount of current being measured during the pulse "on" time, the power measured by the Math channel is rather ambiguous so it will vary between what is seen and ~+2.0mw.  It still equates to a rather high apparent COP."

Yes!   O0
   
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All,

This is a change in topology whereby the circuit connections are inverted that is, the common side of R1 and C1 is now connected to the positive supply rail instead of ground.  This affects the circuit operation greatly by presenting the full resonant current to the positive supply.  In the former common ground connection of R1 and C1, the resonant current is seen only by ground during the driving pulse "low" period.

The new schematic is shown below and it should be noted that the P-channel mosfet M2 operates in both reverse and normal conduction modes to allow energy to be fed back to the power supply.  It should also be noted that the only energy not accounted for here is that required to drive the mosfet gates.

The scope pix shows the waveforms and a Tek current probe is used for the current measurements although a CSR could have been used as well.  For clarity, CH3(pnk0 is the supply voltage and CH2(blu) is the voltage on the negative side of C1.  The sum of the magnitudes of these two voltages is the total presented to the load.  So, pout = (29.67+16.7)^2/7.451e3 = 288.6mw.  The power consumed from the positive supply is seen to be 203.9mw for an apparent COP = 288.6/203.9 = 1.42.

Regards,
Pm

EDIT: There is a measurement error in the above so I will update as soon as the info is corrected.

EDIT2:  The current probe position in the bench test was actually on the right side of mosfet M2 which gave erroneous measurements that included the recirculating current in M2 so the measurements stated are incorrect and the actual COP<1.
« Last Edit: 2018-10-05, 16:25:31 by partzman »
   
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  Intriguing progress, PM - awaiting also you update.

   I do have a question about the new circuit - is it still the case that " The lower the power out the higher the COP and vice-versa"?
   
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  Intriguing progress, PM - awaiting also you update.

   I do have a question about the new circuit - is it still the case that " The lower the power out the higher the COP and vice-versa"?

I'm still sorting out the details but the newest circuit has slightly different operating rules compared to the previous.

Pm
   
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All,

In my previous post #312, I have added a second edit which explains the source of measurement error for that topology that when corrected gives a COP<1.

Instead of pushing ahead at this time, I will wait to see if any more replications similar to Itsu's come forward.

Regards,
Pm
   
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PM,
In earlier tests you had found varying results based on something ,possibly humidity but  local  conditions are playing a part in some way.

You may need to have a reference of some kind, possibly the first apparent high cop circuit which remains un touched as a base line .

I apolagise for stating the obvious but a reference  to a known point will help .After all, this all shoud be impossible right?

SM always pointed to rectifier tubes as an important element ,switching to mosfets after results were "what he wanted"

The best clues I have gleaned, relate to interaction between the local magnetic field and rectifier which may be what you have .

Whatever the case turns out to be , I thank you on behalf of all who are influenced  for your dilligence, aptitude and pragmatisim even skepticisim.
3D



   

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Which topology showed the greatest gain irrespective of operating frequency.

I would think the best approach is to try and use IONs looping circuit to run the best topology, at least the gain can be measured by the amount or lack of hopefully supply power, even if a pot was used with a marked dial to turn up or down the input power a graph could be plotted where the pot needs setting to maintain a set frequency or load, this approach could also be used to study different drive designs, each improvement would be measured against the previous design.
   
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PM,
In earlier tests you had found varying results based on something ,possibly humidity but  local  conditions are playing a part in some way.

You may need to have a reference of some kind, possibly the first apparent high cop circuit which remains un touched as a base line .

I apolagise for stating the obvious but a reference  to a known point will help .After all, this all shoud be impossible right?

SM always pointed to rectifier tubes as an important element ,switching to mosfets after results were "what he wanted"

The best clues I have gleaned, relate to interaction between the local magnetic field and rectifier which may be what you have .

Whatever the case turns out to be , I thank you on behalf of all who are influenced  for your dilligence, aptitude and pragmatisim even skepticisim.
3D

3D,

I totally understand what you are saying and agree 100%.  I do have the elements of the original configurations and run them occasionally for comparison but have not documented the results other than what has been posted.  My inherent problem is that I tend to look too far "forward" sometimes ending up down a path of distraction!

Thank you for your most kind comments!

Pm
   
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Which topology showed the greatest gain irrespective of operating frequency.

I would think the best approach is to try and use IONs looping circuit to run the best topology, at least the gain can be measured by the amount or lack of hopefully supply power, even if a pot was used with a marked dial to turn up or down the input power a graph could be plotted where the pot needs setting to maintain a set frequency or load, this approach could also be used to study different drive designs, each improvement would be measured against the previous design.

Peter,

The parametric charging circuits using mosfets for the non-linear element seem to show the largest apparent gains especially when driven with an increasing frequency sweep.  The question then is if the amount of output power verses gain is sufficient to attempt looping.  There are two types of running for these circuits and that is charge/discharge of a capacitance and continuous.

The topology easiest to loop is the off-resonant type with it's low apparent gains due to the convenience that the output voltage can easily be => the supply voltage.  IOW, the looping circuit is simply achieved by replacing C1 with the power supply.  I have tried this and not experienced self-running to date but I'm not using the most efficient switching circuits at this point in time.  More experimentation needs to be done in this area.

Your suggestion of a variable load is an excellent idea for those unable to generate a charge sweep over time.  I'm sure there are math relationships with various circuit values that would help determine the ideal operating conditions and loads but I'm unable to supply those unfortunately.

IF all else fails, I can see some value in having a simple, extremely efficient boost converter with reasonable regulation at low power levels.  C.C

Pm
   

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Hi partzman
Thanks for the reply, if only I had some free time, I am chomping at the bit to have a go at this device.

I am surprised there's not more people having a go.

Regards
Peter
   
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   Thanks, I'm gathering parts.
    PM -- is the L or size/ferrite of the smaller ferrite-cored coil critical?
   
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   Thanks, I'm gathering parts.
    PM -- is the L or size/ferrite of the smaller ferrite-cored coil critical?

I would not recommend a ferrite cored toroid as it may reach saturation which would reduce efficiency.  Nearly any gapped ferrite core will work and powdered iron toroids as well.  The inductance of L1 could be in the area of what I used and is not critical.  Good luck in your replication!

Pm
   
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Same here, though via the slow boat.
My question is also ferrite related. Have got a couple of CRT yoke ferrites, the big jobbies. I gather that a piece of paper between the halves and a number of windings will suffice ?
But the thinking is about litz and whether it's of use. Especially if the strands are separated and connected as per Romero's device from years ago. Such a method produces a 'super capacitance' coil and might be useful, rather than a single layer winding.   


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ʎɐqǝ from pɹɐoqʎǝʞ a ʎnq ɹǝʌǝu
   
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Same here, though via the slow boat.
My question is also ferrite related. Have got a couple of CRT yoke ferrites, the big jobbies. I gather that a piece of paper between the halves and a number of windings will suffice ?
But the thinking is about litz and whether it's of use. Especially if the strands are separated and connected as per Romero's device from years ago. Such a method produces a 'super capacitance' coil and might be useful, rather than a single layer winding.

The CRT yoke ferrites should work with the paper providing the gap. 

I have tried litz split into two windings for L1 which does result in a relatively large self capacitance but it didn't seem to perform well at all in the circuit.

Pm
   
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