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Author Topic: Parametric Charging  (Read 44049 times)
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This is a new subject dealing with apparent gains seen in diode based capacitor charging circuits utilizing the reverse bias parametric capacitance change of the diode or equivalent.   This all came about from the study of Dr. Stiffler's work and his single wire experiments and disclosures.

This thread was originally private but is now for public viewing.

Regards,
Pm
 
Edit: 9.25.2018
« Last Edit: 2018-09-25, 14:08:52 by partzman »
   
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Dear PM

Thank you for the invite. I am very interested in your work and hope to be able to make some positive contributions.

Regards


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All,

This is a continuation of my previous tests with the latest result of the parametric charger using a rather large CSR of 100 ohms which is reducing the circuit Q but does give very consistent and accurate input power measurements without affecting the circuit performance greatly.  The current probe just does not yield consistent measurements at these low currents!  The schematic below shows the circuit used which has 4 paralleled 1N4148s per leg.

The scope pix below shows a measurement cycle over 100ms with a voltage across C1 at 50 ms of 38.45v mean.  I would like to point out that the circuit has two phases of operation which is important as will be pointed out later on.  This is seen in the large current draw from the start to the ~30ms point where the current then begins to taper off in a linear fashion.

The first data table below was taken with a 40ms horizontal scan and the second was taken over a 100ms horizontal scan with the same start conditions.  These were taken at two different times and I would like to point out the close agreement of the input power measurements when comparing between these tables at the 10-40ms marks.

There appears to be gain in this device and the question is, what is the cause if this is true? 

Regards,
Pm
   
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The parametric charging (PC) circuit shown previously with an applied constant frequency will exhibit two phases as mentioned.  These are due to the resonant frequency differences between C1 being shorted which results in a lower self resonant frequency and a fully charged C1 which will result in a higher self resonant frequency.  This difference is created by the decreasing capacitance of the diodes as the reverse bias voltage increases across them due to the charging of C1 and this diode capacitance change is in series with C2 creating the varying resonant frequency over time. 

Normally, the frequency from the generator is greater than the starting resonant frequency with C1 shorted or discharged.  As C1 charges, the circuit's self resonance frequency increases to a point of being equal to the generator frequency (Phase 1) and then continues increasing to be greater than the generator frequency (Phase 2) and eventually stabilizes at some level depending on circuit Q.   

In measuring and analyzing the previous tests during Phase 2, it seemed apparent that if the proper load value was placed across C1, a gain would be realized in continuous operation.  The following scope pix demonstrate the results.

The first pix is the continuous power input to the circuit which is seen to be 11.54mw.

The second pix shows the voltage across C1 with a 46.5k load resistor attached to be 35.85v mean or dc.  This equates to an output power level of 35.85^2/46.5e3 = 27.64mw. 

This results in an apparent COP = 27.64/11.54 = 2.395.  This is still flea power due to the small capacities and voltages involved but it does show promise IMO.

I might add that the probe measuring the voltage across the CSR uses the probe tip and ground spring directly connected to the resistor leads as is good RF measurement practice.

Regards,
Pm

   
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ION had suggested adding a primary to L1 and driving the primary with the mosfet driver which allows a higher operating voltage level to the circuit.  L1 is currently an air core wound on a 50mm dia pvc form with the primary wound over the secondary and is not an ideal transformer at these frequencies.

Anyway, this test is using the same 46.5k load resistor as previously and at the same frequency of 1.42MHz as can be seen in the schematic below.  The resonance curve has changed but I thought the results would be interesting to post as the power level is creeping upwards.

The first scope pix is the Pin measurement which is 56.52mw.  Note the sample rate of 2.5GS/s.

The second scope pix is the voltage across C1 with the 46.5k ohm load attached and is 75.81vdc.  The output power is 75.81^2/46.5e3 = 124mw.

Therefore, the COP = 124/56.52 = 2.19. 

Pm

   

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ION had suggested adding a primary to L1 and driving the primary with the mosfet driver which allows a higher operating voltage level to the circuit.  L1 is currently an air core wound on a 50mm dia pvc form with the primary wound over the secondary and is not an ideal transformer at these frequencies.

Anyway, this test is using the same 46.5k load resistor as previously and at the same frequency of 1.42MHz as can be seen in the schematic below.  The resonance curve has changed but I thought the results would be interesting to post as the power level is creeping upwards.

The first scope pix is the Pin measurement which is 56.52mw.  Note the sample rate of 2.5GS/s.

The second scope pix is the voltage across C1 with the 46.5k ohm load attached and is 75.81vdc.  The output power is 75.81^2/46.5e3 = 124mw.

Therefore, the COP = 124/56.52 = 2.19. 

Pm

Pm

If the 100r CSR is placed between Ls and the diode array,dose this still give you the same P/in value ?.

Im just thinking maybe most of the P/in is via single wire/avamenco plug type deal here-maybe ? via the positive path.

Added-also,have you included the dissipated power of the 100r CVR in any of your P/out calculations at any point in time ?
Brad
« Last Edit: 2018-08-23, 05:10:16 by TinMan »


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Ok,so now you have my attention Pm  O0

Below is a pic of my setup,and the schematic to go with it.

I decided to give the 1n4007s a go as my diode array,and larger capacitor values to try and get the frequency down.
Well seems i have achieved that,as the frequency is down to just 27.9KHz  O0

The wave forms on the scope are very clean,but making the calculations from the scope is going to be trick,as some of the forward voltage is being recycled through the transformer,and so average cannot be used to make the calculation.

In the schematic,you will see i have added another CVR on the front end,as i had my suspicions that the CVR in position 2 (CVR 2) would not be giving the correct information to use as the current CVR.
The wave form across CVR1 is very different to that of CVR 2.
For my P/in calculations i have used CVR1.

In saying all that,i think we must be missing something here,as my COP is very high  :o

P/in(tonight) was calculated by using my DMMs,as at this low frequency they are very accurate.
V/in was taken by placing the DMM across the primary of L1.
I/In was taken by placing the DMM across CVR1,and measuring the voltage. Then current was calculated using ohms law.

The scope shows(oddly enough)that the voltage and current are dead in phase,and so the power factor is 1  O0
Both DMMs are a different brand,and both show the same voltage readings across CVR 1 and the primary of L1
Scope was used to confirm measurements.

So P/in was calculated to be--
I/in=165mV across 10 ohms=16.5mA
V/in=165mV across L1 primary.Scope average did not agree with DMM in this case--something to look into there.
Scope gave an average voltage of 355mV

Yes,oddly enough the voltage across the primary was the same as the voltage across CVR1 :o
So P/in =2.722mW

P/out is 26.2v over the 15k resistor.
The voltage across R1  C1 was taken with my DMM and scope. Both agree with each other.
P/out=45.762mW

Apparently the COP is 1681%-->!!Apparently!!

I find it hard to believe that both DMMs would be out the very same amount.
My top end DMM has been used many times,and is accurate with pulsed DC far above the frequency being used here.
!BUT! something is not right some where?

What we need is to brainstorm the most accurate way to calculate P/in.
P/out is no problem,as it is smoothed DC across a known resistance.

I will be doing the long hours on this tomorrow night for sure.


Brad

Added
I am driving the circuit with my SG.
« Last Edit: 2018-08-23, 16:19:22 by TinMan »


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Just out of curiosity,i removed L1,C2,and CVR 2,and without changing anything on the SG,i placed the SG across the diode array.
The maximum voltage achieved across C1/R1 was 12.4 volts,for a dissipated power of just 10.25mW

Interesting stuff  O0


Brad


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Pm

If the 100r CSR is placed between Ls and the diode array,dose this still give you the same P/in value ?.

Im just thinking maybe most of the P/in is via single wire/avamenco plug type deal here-maybe ? via the positive path.

Added-also,have you included the dissipated power of the 100r CVR in any of your P/out calculations at any point in time ?
Brad
Brad,

Excellent question and one that I had considered but talked myself out of because normally, the current entering a network will equal the current exiting the network.  This is true however, at these frequencies, there are obvious capacitive conduction paths that I have not accounted for because the current entering the diode/capacitor network is greater than the current exiting the same network.  Therefore, the power measurements taken on the loaded device continuously running with the CSR at the output of the network are too low.  In fact, when the CSR is placed at the network input and the current measured differentially, the COP = .79 or so.

Now the question is, has this affected all my measurements on all the previous tests?  I'm afraid that perhaps this is the case but I will do the tests to find out.  I have seen gains in the lower frequency range of 500-600kHz but these too will be suspect to error.

I've attached a pix of the 3.94uf cap used along with the attached diodes as one can see, I've at least made a nice 1-2MHz antenna array! :-[  There is a lot of surface area to this composite cap that is coupled to any ground surface in the area and I believe this is the basic problem involving the measurement error.

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This is a lower frequency test at 687kHz with a few value changes plus I'm back to the current probe placed at the input of L1.  In order to raise the current measurement well above the noise floor, I have passed the sense lead thru the probe 4 times to raise the measurement level 4x and then compensated in the Math channel with a division by 4.  This gives consistency of the current measurement with the probe and all the input current is accounted for.

The schematic below shows another change and that is the parametric device is now an RFP14N0L5 mosfet.  This device has a BVdss breakdown voltage of ~50 volts but they typically will reach 65-70v as is the case with the devices used here.  When the circuit reaches that level across C1, the voltage increase stops and the pin stays relatively constant.

The data table for a 100ms scan is also attached and can be seen, we still have apparent OU.  The goal from here is to attempt reaching lower frequencies with gain.

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Pm

I am down to a frequency of just 27.9KHz,and measured as you have,i get very high COPs

I believe that the measurement across your CSR 1 should be the RMS value,and not the mean value you have been using,as your transformer secondary will be feeding the circuit an AC .

The diode array is just a double diode FWBR,and i think in my case,it is working just as that-an FWBR.

I will spend some more time on it tonight,and try and work out why the COP seems so high.


Brad


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Ok,so now you have my attention Pm  O0

Below is a pic of my setup,and the schematic to go with it.

I decided to give the 1n4007s a go as my diode array,and larger capacitor values to try and get the frequency down.
Well seems i have achieved that,as the frequency is down to just 27.9KHz  O0

The wave forms on the scope are very clean,but making the calculations from the scope is going to be trick,as some of the forward voltage is being recycled through the transformer,and so average cannot be used to make the calculation.

In the schematic,you will see i have added another CVR on the front end,as i had my suspicions that the CVR in position 2 (CVR 2) would not be giving the correct information to use as the current CVR.
The wave form across CVR1 is very different to that of CVR 2.
For my P/in calculations i have used CVR1.

In saying all that,i think we must be missing something here,as my COP is very high  :o

P/in(tonight) was calculated by using my DMMs,as at this low frequency they are very accurate.
V/in was taken by placing the DMM across the primary of L1.
I/In was taken by placing the DMM across CVR1,and measuring the voltage. Then current was calculated using ohms law.

The scope shows(oddly enough)that the voltage and current are dead in phase,and so the power factor is 1  O0
Both DMMs are a different brand,and both show the same voltage readings across CVR 1 and the primary of L1
Scope was used to confirm measurements.

So P/in was calculated to be--
I/in=165mV across 10 ohms=16.5mA
V/in=165mV across L1 primary.Scope average did not agree with DMM in this case--something to look into there.
Scope gave an average voltage of 355mV

Yes,oddly enough the voltage across the primary was the same as the voltage across CVR1 :o
So P/in =2.722mW

P/out is 26.2v over the 15k resistor.
The voltage across R1  C1 was taken with my DMM and scope. Both agree with each other.
P/out=45.762mW

Apparently the COP is 1681%-->!!Apparently!!

I find it hard to believe that both DMMs would be out the very same amount.
My top end DMM has been used many times,and is accurate with pulsed DC far above the frequency being used here.
!BUT! something is not right some where?

What we need is to brainstorm the most accurate way to calculate P/in.
P/out is no problem,as it is smoothed DC across a known resistance.

I will be doing the long hours on this tomorrow night for sure.


Brad

Added
I am driving the circuit with my SG.
Brad,

If you have time, could you take a scope shot of your input waveforms.  Maybe we can work out from there how you are getting such a high COP.  I can't seem to find a reverse bias capacitance curve for the 1N4000 series diodes and you are at such a low frequency that I'm not sure if you are seeing a parametric effect or not.

Does your scope have math capability?

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Brad,

If you have time, could you take a scope shot of your input waveforms.  Maybe we can work out from there how you are getting such a high COP.  I can't seem to find a reverse bias capacitance curve for the 1N4000 series diodes and you are at such a low frequency that I'm not sure if you are seeing a parametric effect or not.

Does your scope have math capability?

Pm

I believe the 1n4000 series diode capacitance value is 15pf at 4v-1MHz.

My new 4ch scope has all the fruit,just need to learn how to use it.

I will be doing more testing tonight,and get you some wave forms.

The wave forms are preaty  clean,and we can calculate the instantaneous P/in,then devide by duty cycle.
But there is a question with the voltage due to feedback,which i will point out tonight.

I'll get a video up,and show you what is going on.


Brad


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OK Pm,let me see if i can get all this in order.

First pic is of a quick test i did.
Using two of the 1n4007s reversed biased,in series with an LED polarity correct,i connected the SG across the circuit.
The SG was left as it was when driving the diode array circuit.
The aim was to see if the diodes had enough junction capacitance at that lower frequency(30KHz)to run the LED.
Turns out the LED lit up quite well. Even at 10KHz,the LED will light.

Second is the schematic with scope probe positions,and component values--except inductance values of the transformer.

OK,the first scope shot shows the current(blue trace) across the 10 ohm CVR,and the voltage(yellow trace)across both the 10 ohm CVR,and the secondary of the transformer.
So this is where our P.in is taken from,as it is the input to the circuit.

The second scope shot is where i have removed everything other than the 20% on time.
What you see left in that scope shot is what is used to calculate P/in.

In the third scope shot,i have drawn a red box around the 20% on time of the SG.

The forth scope shot shows everything that is going on in the remaining 80% of each cycle,where i have removed the 20% P/in part of each cycle.

You will note that !some how! the value of current is higher in both directions during the off time,than it is during the on time--through the same inductor(the secondary).
You can see that the flyback current value is far greater than the current value during the on time,and then the bounce back current just before the next cycle starts,is also higher than that during the on time.
Now,i was always told that the maximum current you could get during the flyback period would never be higher than that of the maximum current flowing through the inductor during the on time period.
Seems they were wrong ?.

Anyway,my calculations are as follows.

I have calculated the voltage across the 10 ohm CVR during the 20% on period,to be an average of 35mV-or close to.
The voltage seems to be a steady 50v during the on time period.
So P/in is 50v X 3.5mA=175mW.
This is the power for the 20% on time,and so we divide that by 5 to get average power in.
So P/in is 35mW.

P/out is 28.6v over the 15kohm resistor
P/out = 54.53mW
COP=155.8%


Brad


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I offer this Real Time Tuning Method to aid in finding optimum parameters.

I liken it to engine tuning, where you help the engine to run a bit with an external current source and adjust parameters for less dependency on the external current source. (External current source is like the "starter" in a ICE.)

A breakdown device is used to dump some energy from the C1 cap to shock excite a tank coil comprised of the L1 primary and the variable cap C2, which may be deleted if you want to run solely on the self resonance of L2.

The firing point of the breakdown device is another parameter that is part of the tuning, and it should occur as the system is approximately at the maximum parametric charging of C1.

I wish I had time to build this right now but am bogged down with other stuff. I think it would be fun to play with the tuning to see how great a dip in external supplied current could be achieved towards self running.

Regards

edit: post updated to show suggested starter circuit / external current source
« Last Edit: 2018-08-25, 15:00:49 by ion »


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Brad,

OK ,this helps.  At first glance I question whether it is accurate to sample the secondary output and use the 20ms input pulse period to arrive at the input energy consumption but I'm probably wrong.  I think it might be better to compute the entire secondary output voltage and current to arrive at the input to the diode/cap circuit ( this would require using your math channel) or, place the CSR back in the primary and measure the primary voltage and current for input power. 

In any case, you may have something here placing the charging of a cap in a series resonant loop.  I will try a single coil version of your circuit at low frequency to hopefully replicate what you've done as I don't have a transformer on hand that matches yours which has a leakage inductance of ~23mH.

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All,

Here is a continuous run test based on the parameters and data for the circuit shown in post #9.  After analyzing the data, I felt that there should be an energy gain running continuously at 687kHz with a load resistor across C1 that resulted in a C1 voltage of ~24v dc.  Experimentally this value was found to be 15k ohms and the scope shots below show the results. 

The first scope pix shows the input power to be 18.81mw.

The second scope pix shows the voltage across C1 with the 15k attached to be 24.61v for an output power of 24.61^2/15e3 = 40.3mw.

This results in an apparent COP = 40.3/18.81 = 2.14.

This is an easy method of proving or disproving the circuits ability to produce a gain.  I have been trying different mosfets and diodes at these lower frequencies and this is the best combo thus far.

I think that the circuit can be reduced even further by using a full wave center tapped secondary with on two diode elements which should increase the parametric capacitance 2x as compared to the bridge circuit due to the fact that the parametric capacitances are connected in series for each polarity.  This should possibly allow a lower operating frequency.

Regards,
Pm
   
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I offer this Real Time Tuning Method to aid in finding optimum parameters.

I liken it to engine tuning, where you help the engine to run a bit with an external current source and adjust parameters for less dependency on the external current source. (External current source is like the "starter" in a ICE.)

A breakdown device is used to dump some energy from the C1 cap to shock excite a tank coil comprised of the L1 primary and the variable cap C2, which may be deleted if you want to run solely on the self resonance of L2.

The firing point of the breakdown device is another parameter that is part of the tuning, and it should occur as the system is approximately at the maximum parametric charging of C1.

I wish I had time to build this right now but am bogged down with other stuff. I think it would be fun to play with the tuning to see how great a dip in external supplied current could be achieved towards self running.

Regards

ION,

For some reason I didn't see your post until now but I think it is a great idea.  There seems to be too much to do and too little time at the moment but I plan to implement your circuit.  On thing to note is the circuit can get unstable in the sense that if the load resistance is too high or the frequency too low, it will snap to produce maximum voltage across C1 and is very inefficient in this mode.  The breakdown voltage of the 14N05L presently clamps the output to ~68v or it would head to........?

Anyway, more later.

Regards,
Pm
   

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 author=ion link=topic=3655.msg69355#msg69355 date=1535127090]
Quote
I offer this Real Time Tuning Method to aid in finding optimum parameters.

I liken it to engine tuning, where you help the engine to run a bit with an external current source and adjust parameters for less dependency on the external current source. (External current source is like the "starter" in a ICE.)

A breakdown device is used to dump some energy from the C1 cap to shock excite a tank coil comprised of the L1 primary and the variable cap C2, which may be deleted if you want to run solely on the self resonance of L2.

The firing point of the breakdown device is another parameter that is part of the tuning, and it should occur as the system is approximately at the maximum parametric charging of C1.

I wish I had time to build this right now but am bogged down with other stuff. I think it would be fun to play with the tuning to see how great a dip in external supplied current could be achieved towards self running.

Regards
.

Thanks ION

If you have time,could you join in and check my measurements in my next post  O0.

Pm's circuit is very simple,and i recommend those here that can-join in.


Brad


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First off,i do agree with Pm that my setup may not be working as intended(parametric charging),but the circuit is the same,and interesting results are being had.

This will be a long post,as i am at the point where great care must be taken in power measurements,and the events actually taking place at each point in time throughout the circuit.

My measurements are taken from continuous running of the circuit.
The P/out measurements are very simple,as it is a smooth DC voltage across a 15kohm resistor(value checked with 3 different DMMs)

OK,the first schematic is in reference to scope probe placement for P/in measurements.
Scope shot one shows current(blue)and voltage(yellow) traces for P/in measurements.

Scope shot 2 shows a reverse current flow through the primary of the transformer,even though there is a blocking diode on the positive input to the primary winding of the transformer. This will be explained a little later down.

Scope shot 3 shows a time base expanded view of the traces,and where i have averaged both the current and voltage values for the 25% on time(P/in time)
You will note that the current and voltage are in phase,and this can be explained easily a little further on down.

So my P/in is calculated as such

Average current for on time is 1.4v across the 10 ohm CVR (CVR1)
So our current during the on time is 140mA.
Our average voltage across the primary is calculated as being an average of 3.9v- the 1.4v across CVR1 for an average of 2.5v across the primary winding for the 25% on time.

So the P/in for 25% of each cycle is 2.5v X 140mA=350mW

From this we subtract the power dissipated by CVR1,which is 1.4v across 10 ohms=196mW.
This gives us the P/in to the circuit as being 350mW-196mW=154mW.
P/in is 154mW for the 25% on time for each cycle.
Average P/in is 154mW/4-->or 154mW X 25%.
Our average P/in is 38.5mW.

Ok,now we look at the reverse current flow through CVR1,even though the primary has a blocking diode on the positive rail.

The reverse current flow seen across CVR1 is current being transferred via capacitive coupling between the primary and secondary windings of the transformer.
I confirmed this by placing ch1 of the scope across CVR2,while leaving ch2 across CVR1--see test circuit 1B.
In scope shot 4,we can clearly see the reverse current flow shown across CVR1(the transformers primary) also existing across CVR2(the transformers secondary current).
This confirms current being transferred from primary to secondary,via capacitive coupling,and not current being returned to the source through the blocking diode on the primaries positive input rail.


Now the vertical rise of current during the 25% on time,and the current and voltage being in phase.

When we look at the scope shots,we will notice that we already have a forward voltage across the primary of the transformer of close to 2.2 volts just before the 25% on time part of the cycle starts. You will also notice at that time there is 0 volts across the CVR. This means the actual forward voltage across the primary just before P/in starts is actually 2.2 volts.

This is the reason that we see a vertical current trace as P/in starts,and also the reason the voltage and current are in phase.

P/out is easy,as it is a stable DC voltage across the 15kohm resistor (R1)
P/out is 36.8 volts across 15kohms=90.28mW

COP=234.49%


My next step is to increase the size of the DUT.
Im thinking along the lines of a MOT,and driving the input via mosfet or transistor.


Brad
« Last Edit: 2018-08-25, 13:40:35 by TinMan »


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OK,today was another full day of testing,and trying out some other transformers on new setups for higher power conversions.

What i found was this--
Using transformers where the primary and secondary are wound separately(such as MOTs),did not yield any OU results.
High frequency transformers that have the primary and secondary wound together(one over the top of the other,or bifilar type) all yielded OU results.
I put this down to the capacitive coupling between primary and secondary windings playing a vital roll in these circuits. The capacitive coupling between primary and secondary windings on transformers with separate windings will have a value of next to 0,and probably why they do not show OU results.

Going back to the original circuit(as it yields the best results so far),i carried out 3 different tests.
I have made a couple of modifications to the circuit.
I have increased C1s value to 2200uF,and added another diode in series on the input rail.
This was to halve the junction capacitance of the input diode(well,i think it would ?),so as to reduce any feedback to the source(my SG),and sending it to C1 instead--see circuit below for mods.

The needed information and calculations are attached to each scope shot.
Blue chanel across CVR1,and yellow chanel across CVR1 and primary coil.


Brad
« Last Edit: 2018-08-25, 16:19:03 by TinMan »


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Post #14 updated to include suggested starter circuit / external current source.

Note also that other types of oscillators can be tried such as single transistor or push pull types. I chose to start with negative resistance oscillators for practically no loading of C1 up to the firing point, after which bursts are generated due to capacitor discharge into tank circuit.


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OK,today was another full day of testing,and trying out some other transformers on new setups for higher power conversions.

What i found was this--
Using transformers where the primary and secondary are wound separately(such as MOTs),did not yield any OU results.
High frequency transformers that have the primary and secondary wound together(one over the top of the other,or bifilar type) all yielded OU results.
I put this down to the capacitive coupling between primary and secondary windings playing a vital roll in these circuits. The capacitive coupling between primary and secondary windings on transformers with separate windings will have a value of next to 0,and probably why they do not show OU results.

Going back to the original circuit(as it yields the best results so far),i carried out 3 different tests.
I have made a couple of modifications to the circuit.
I have increased C1s value to 2200uF,and added another diode in series on the input rail.
This was to halve the junction capacitance of the input diode(well,i think it would ?),so as to reduce any feedback to the source(my SG),and sending it to C1 instead--see circuit below for mods.

The needed information and calculations are attached to each scope shot.
Blue chanel across CVR1,and yellow chanel across CVR1 and primary coil.


Brad

Brad,

These are very interesting results, O0 but I think you forgot to attach the modified schematic.  I agree with your calculations on your post previous to the modified version and I also agree with your capacitive coupling analysis between primary and secondary.

Late last night I tried a single inductor version of your circuit and it did not produce your waveforms or any OU.  This would support the importance of capacitive coupling between windings rather than the importance of the leakage inductance.

What is the voltage step up or down ratio of the transformer that gives you the best performance?  Also, what is the core material?

Carry on-

Pm 

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TM and PM,

i used the diagram on post #9 above to replicate using:

V1 = IXDN614PI MOSFET driver on 40V  (driven by my FG)
L1 = 322uH (measured) on 5cm OD former
C1 = 5.015uF (measured) 2x 10uF/50V WIMA caps in series
C2 = 3274pF (measured)
Mx = 4x IRF3205 MOSFETs
R1 = 14.86KOhm (measured) load resistor across C1

I think the resonance frequency is around the shown (screenshots) 466Khz. 
Probes are as indicated on the post #9 diagram (including the 4 turns for the current probe).
Blue marker is underneath the red marker on the left side
 
Not sure the current probe is in the righ way, see picture, but this gives positive values (inverted the green trace).

Anyway, is this what i have at resonance, not sure what PM means on his table by sweep (ms).

screenshot 1 is with input calcs (yellow x green = red) 6.2w / 4 =  1.55W     (/ 4 because the 4 turns on the current probe)
screenshot 2 is with output calcs (blue - purple= red)  91V across 14.86KOhm = 560mW

Itsu
« Last Edit: 2018-08-25, 18:07:07 by Itsu »
   

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Buy me a beer
Hi Brad

Should not your circuit be as I have posted below with the addition of the red cables?

Just to clarify :)

Interesting stuff now coming out from all directions but in a similar area.

Regards

Mike 8)


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