All,
I have started this thread so that we can communicate with Bob without crashing his Internet browser. Please do not attach any images of any kind here! ;)
Bob,
I put a transformer secondary (must be at least 1 Henry) as an HF choke between the filtered HV potential supply and the secondary winding, but the DC potential still does not seem to have any effect on the output. My estimated COP is somewhere around 0.1, pretty bad! ;D
Can you see anything else wrong? I have even upped the voltage on my MOSFET drivers to 10V highly filtered DC to see if there were any problems there. I have been running frequency sweeps from 10KHz to 50KHz, and at no point does the COP increase.
Also, maybe another clue, changing the phase slightly does not increase power on the output. When I have the DC potential circuit charged, the core doubles or triples its audible noise output, but the output waveforms look exactly the same as before I charged the DC potential circuit.
My output circuit right now consists of the 120V inverter feeding a bridge rectifier. There is a large electrolytic capacitor across the output of the bridge rectifier. Positive HVDC goes to the HF choke, and then from the choke to the secondary winding. The other end of the secondary connects to the 0.68uF mylar capacitor, and then the other end of that capacitor connects to the load, which then completes the circuit to Earth ground. The negative HVDC terminal also connects to Earth ground.
On the input side, I have three of the primary coils, equidistant from each other, with all of the CCW ends connected to +13.8VDC. The CW ends go to the respective pulse generation MOSFETs, which are set to a pulse width of 5000ns. The ground of the signal generator is connected to Earth ground as well.
Just wondering if you might have some more ideas for me to try... :)
Thanks!
Eldarion
EDIT: I wanted to see if switching time might have been an issue, so I connected my 20ns rise/fall time MOSFET drivers directly to the primary coils in open-ended mode. The HV potential still had no effect, even with those beautiful pulses on the input. :) Not really sure what is going on here; maybe I can call you tomorrow (Saturday) and we can hash out what I am doing wrong?
I'm good to go for a phone call today if you wish.
Bob
Bob,
Could you PM me your phone number?
Thanks!
Eldarion
Quote from: eldarion on October 13, 2007, 01:06:53 PM
Bob,
Could you PM me your phone number?
Thanks!
Eldarion
Phone number sent
Bob
@ Bob
Just a big thank you for helping Eldarion out. We will all keep this thread clear of any images, to ease all communication, for all the replicators, as they run into any future challenges.
Cheers,
Bruce
Hi Bob,
I received a new batch of MAX627 driver chips today, so I went ahead and fired up the controller again. Nothing interesting happened! :o :-[
Connecting either end of the secondary to ground did not short out the lamp like it did last time. COP is now far below 1, and I am scratching my head trying to figure out what happened! :D It is almost as if LMD had manifest in the previous attempt (multiple times and on-demand), but now all I am getting is TEM.
The only thing that I can think of is that the primary drive signals have more oscillation on them than before. Once again, I have no idea how this happened, and I have yet to figure out a way to damp it out. LMD will not manifest with large-amplitude oscillations in the primaries, correct?
Had a bad drive chip, I think. Replaced it and the signals are pretty clean again. Still not working, though.
Running frequency sweeps still changed the intensity of the bulb in a nonlinear fashion, but with the COP so low I couldn't get anything interesting to happen. LMD generation seems rather finicky...
Any ideas would be welcome! ;)
Eldarion
Quote from: eldarion on October 22, 2007, 05:45:44 PM
Hi Bob,
I received a new batch of MAX627 driver chips today, so I went ahead and fired up the controller again. Nothing interesting happened! :o :-[
Connecting either end of the secondary to ground did not short out the lamp like it did last time. COP is now far below 1, and I am scratching my head trying to figure out what happened! :D It is almost as if LMD had manifest in the previous attempt (multiple times and on-demand), but now all I am getting is TEM.
The only thing that I can think of is that the primary drive signals have more oscillation on them than before. Once again, I have no idea how this happened, and I have yet to figure out a way to damp it out. LMD will not manifest with large-amplitude oscillations in the primaries, correct?
Had a bad drive chip, I think. Replaced it and the signals are pretty clean again. Still not working, though.
Running frequency sweeps still changed the intensity of the bulb in a nonlinear fashion, but with the COP so low I couldn't get anything interesting to happen. LMD generation seems rather finicky...
Any ideas would be welcome! ;)
Eldarion
How is the load connected? Remember, LEM will want to flow mostly from the secondary to ground, but you cannot ground or apply the DC potential the other side of the secondary unless you run it through a healthy choke first. Across both ends of the secondary would be some TEM, at low COP. If running in pulsed mode the longitudinals will not produce DC, but rotational mode should.
Bob
Almost forgot, getting rid of one of my old hydroxy version HexControllers on eBay ;-)
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=220163319193
Quote from: Bob Boyce on October 22, 2007, 10:48:59 PM
Quote from: eldarion on October 22, 2007, 05:45:44 PM
Hi Bob,
I received a new batch of MAX627 driver chips today, so I went ahead and fired up the controller again. Nothing interesting happened! :o :-[
Connecting either end of the secondary to ground did not short out the lamp like it did last time. COP is now far below 1, and I am scratching my head trying to figure out what happened! :D It is almost as if LMD had manifest in the previous attempt (multiple times and on-demand), but now all I am getting is TEM.
The only thing that I can think of is that the primary drive signals have more oscillation on them than before. Once again, I have no idea how this happened, and I have yet to figure out a way to damp it out. LMD will not manifest with large-amplitude oscillations in the primaries, correct?
Had a bad drive chip, I think. Replaced it and the signals are pretty clean again. Still not working, though.
Running frequency sweeps still changed the intensity of the bulb in a nonlinear fashion, but with the COP so low I couldn't get anything interesting to happen. LMD generation seems rather finicky...
Any ideas would be welcome! ;)
Eldarion
How is the load connected? Remember, LEM will want to flow mostly from the secondary to ground, but you cannot ground or apply the DC potential the other side of the secondary unless you run it through a healthy choke first. Across both ends of the secondary would be some TEM, at low COP. If running in pulsed mode the longitudinals will not produce DC, but rotational mode should.
Bob
Almost forgot, getting rid of one of my old hydroxy version HexControllers on eBay ;-)
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=220163319193
Ahh...that might explain it. I just had the 60W light bulb hooked up across the two secondary terminals, not between ground and one end of the secondary. Putting in about 30W caused the bulb to glow dimly in that configuration.
So I take it that for optimal LMD creation, the "free" end of the secondary (not connected to the load) should be connected through a choke to some sort of HV potential, but never to ground? I am also guessing that is should not be left floating?
I am always testing in rotational mode; I don't even want to bother with pulsed mode unless absolutely necessary. I did scope across the bottom longitudinal winding, and did not see any DC offset. So do I have to have the system in full LMD overunity mode before the DC offset will show up?
Thanks!
Eldarion
Quote from: eldarion on October 22, 2007, 10:55:02 PM
Ahh...that might explain it. I just had the 60W light bulb hooked up across the two secondary terminals, not between ground and one end of the secondary. Putting in about 30W caused the bulb to glow dimly in that configuration.
So I take it that for optimal LMD creation, the "free" end of the secondary (not connected to the load) should be connected through a choke to some sort of HV potential, but never to ground? I am also guessing that is should not be left floating?
I am always testing in rotational mode; I don't even want to bother with pulsed mode unless absolutely necessary. I did scope across the bottom longitudinal winding, and did not see any DC offset. So do I have to have the system in full LMD overunity mode before the DC offset will show up?
Thanks!
Eldarion
The free end can be left loose, but unless that secondary is within a modulated potential field, it will collect little LEM. I am under the impression that LMD and LEM are different things. LMD is longitudinal potential, while LEM is longitudinal potential that has been modulated for collection.
If you are not seeing DC on the longitudinals, then your field may not be rotating cleanly. Double check your waveforms and timing.
Bob
Hey Eldarion,
you might try putting a cup of water nearby to see if the field has any effect on it. When you get the field rotating properly, the water might respond to it.
Keep up the great work!
God Bless,
Jason O
Thanks for the help! I will try to use the terms LMD and LEM properly next time. ;)
Another one of the IGBTs was apparently on the fritz; it decided to blow just a little while ago. This seems strange, as I am not stressing the bricks by any means (13.8V @ 6A maximum)! I guess they may have been damaged in their prior life. So far, both bricks have failed short-circuit.
This might explain my problems; a dying brick could cause the waveforms to be distorted enough to kill the effect, I suppose. I hope that is all it is, and that replacing the bad brick will restore the odd effects I was seeing earlier.
The first replacement brick has already been sent out; I am trying to decide if I should complain about this one that just blew or not.
Eldarion
Quote from: Jdo300 on October 23, 2007, 01:06:47 PM
you might try putting a cup of water nearby to see if the field has any effect on it. When you get the field rotating properly, the water might respond to it.
Thought I was the only one that tried this sort of thing...
Quote from: Grumpy on October 23, 2007, 05:01:56 PM
Quote from: Jdo300 on October 23, 2007, 01:06:47 PM
you might try putting a cup of water nearby to see if the field has any effect on it. When you get the field rotating properly, the water might respond to it.
Thought I was the only one that tried this sort of thing...
Nope ;D. I know this works. Moab and I played around with this when he was testing his TPUs and at one point, he was able to make standing waves in a cup of water that was sitting in the middle of his ring :). It was pretty cool.
I hear from the MAGVID group that adding a little salt to it enhances the effect too.
God Bless,
Jason O
Jason, Grumpy,
If we get odd things happening in a cup of water, I would be seriously concerned about the health risks of this system. After all, we humans are mostly water... :o
All, especially Bob,
The replacement IGBT finally came, and I was also able to borrow a good 150MHz digital storage oscilloscope through the beginning of December. This should help us nail down the problem with my controller, I hope! ;)
I put a scope shot up on one of my websites here:
http://www.falconir.com/pics/DSC02278.JPG
The bottom trace (channel 1) is the "gate" (IGBT base) drive signal, and the top trace (channel 2) is the switched end of the primary coil. This is F1, the highest frequency, set to a 500ns pulse width. Just look at all that awful ringing! >:( I am pretty sure this is why nothing is happening--the field has major errors in it! Every time the potential drops to near zero on the ringing sine wave, the rotation of the electric field gets messed up. The magnetic field is probably also messed up, as the ringing will cause a small oscillating magnetic field to be generated in the primary.
Hmmm...now to get rid of it. Fast, high-power snubber diodes? Maybe Schottky?
EDIT: This is how I will do it: http://www.falconir.com/pics/snubber.JPG
I have some high-voltage silicon carbide Schottky diodes coming in the mail for testing--if possible, I will see if I can use a cheaper standard Schottky diode instead.
Eldarion
this is a carbon copy with no photos of my reply at:
http://www.overunity.com/index.php?topic=2872.msg56117#msg56117
Eldarion,
ringing is usually caused by
leakage inductance
leads too long
current loops too long
a toroid usually has low leakage inductance.
most people have trouble understanding that a circuit operating at 67 kHz, still needs to be built as if it was operating at hundreds of MHz, even 1 GHz, if there are pulses with fast rise and fall times. Circuits with fast edge transistions MUST USE VERY SHORT LEAD LENGTHS. By short, I mean ZERO mm. Since zero mm is not possible, do every thing in your power to approach zero as close as you can. Spare no effort.
Notice that your gate voltage has ringing that even goes negative.
Remember my image of current loops. Look at this image again and ask yourself if all 3 of your currents loops have a length close to zero?
Is the distance between the ground of the driver IC and the IGBT source = to zero?
Don't forget E = L * di/dt and since we want di/dt to approach infinity to have RE effects, L must approach zero.
Even nanoHenries of inductance can cause sufficient and undesired voltage bounces.
Why do you think PCB designs use maybe a dozen SMD ceramic caps around each microprocessor? The multilayer PCB has one layer dedicated only to being a ground plane.
These caps and CPU ground are connected to through-holes directly to the ground plane.
Post some photos in your thread of your physical layout, and I can make some more comments.
Would like to see a scope photo full screen of just the area in the attached photo.
Regards, Earl
Hi Earl,
Yes, I am very well aware of all of that! ;) If you notice what I wrote earlier, I am still waiting on my PCBs--for these tests, I am still using the old hand-wired MOSFET driver board. The new PCBs have extensive bypassing capacitors, and the SMD capacitors are physically right up against the SMD UCC27322 chips. The only issue might come from the physical size of the IGBT bricks (and therefore the lead length required to connect to them), but seeing as they are switching cleanly on these atrocious gate waveforms, I do not think there will be an issue with gate drive.
The bigger issue here is that the IGBT, when a pulse occurs, sets up a small magnetic field in the primary. Then, when it turns off, it essentially open-circuits that end of the primary. What is the magnetic flux going to do? It can't instantly vanish, so it causes those oscillations, and at a much higher voltage amplitude due to the open-ended circuit. I think a snubber will work wonders here; I just need to get my hands on the diodes I ordered before I can try.
Eldarion
Hi Bob,
Would it be possible for you to post scope shots of the three PWM3F channels hooked up to the coil primaries?
I am having a terrible time getting this thing to work, and I would like to compare my waveforms against yours to see if I can find the problem faster. I have already found the scope shots you put over on the WorkingWaterCar group, but those were taken without the coil's primaries hooked up to the PWM3F, as far as I can tell.
I tried adding the snubber diodes, and while they did clean up the drive waveform, they also dramatically increased power input (x10!!) and almost completely shut off the secondary winding's output. Further poking around revaled the source of the oscillation as the secondary winding itself, coupling back into the primaries.
I am still getting no DC voltage on the longitudinal winding(s), and I have quadruple checked the pulse sequencing and hookups. Also, adding the HV potential still has no effect, so something is still wrong here. :(
As always, thank you for all of the invaluable assistance you have been providing to this group! :) Hopefully we can figure out what is wrong quickly...
Eldarion
EDIT: Maybe the rise/fall times on my gate driver are actually too fast, thus giving rise to the atrocious ringing. I went ahead and added 470 ohms of series resistance to the gate driver output in order to slow down the transition a bit and "shape" the pulse, and the ringing all but disappeared on that primary coil. I have not yet had a chance to try the 470 ohm resistor on the other two primaries.
Am I thinking correctly here? I am assuming that the ringing is going to destroy the effect far faster than a slightly slower rise/fall time on the pulses.
Quote from: eldarion on October 25, 2007, 11:15:56 AM
Hi Earl,
Yes, I am very well aware of all of that! ;) If you notice what I wrote earlier, I am still waiting on my PCBs--for these tests, I am still using the old hand-wired MOSFET driver board. The new PCBs have extensive bypassing capacitors, and the SMD capacitors are physically right up against the SMD UCC27322 chips.
The only issue might come from the physical size of the IGBT bricks (and therefore the lead length required to connect to them),
The source connection on the IGBT is the center of the universe. Everything revolves around it. The only correct way of doing things is to physically mount all electronics such that the ground pin of the UCC27322 has zero mm length to the IGBT source. There must be no wires between the UCC27322 ground and the IGBT source. That is the correct way of doing things, there are millions of incorrect ways.
.... but seeing as they are switching cleanly on these atrocious gate waveforms, I do not think there will be an issue with gate drive.
The bigger issue here is that the IGBT, when a pulse occurs, sets up a small magnetic field in the primary. Then, when it turns off, it essentially open-circuits that end of the primary. What is the magnetic flux going to do? It can't instantly vanish, so it causes those oscillations, and at a much higher voltage amplitude due to the open-ended circuit. I think a snubber will work wonders here; I just need to get my hands on the diodes I ordered before I can try.
The voltage across the inductance can, and does, instantly change polarity. Either the switching device has enough voltage breakdown or
1- it blows up
2- goes into avalanche breakdown and depending upon the pulse energy and avalanche rating either survives or blows up.
Using an R/C snubber is very inefficient and usually generates a lot of heat and increases rise time significantly.
My secret is to use a series ferrite bead & C. I don't use R/C or diode snubbers.
By selecting the proper ferrite bead from a developers kit and using the proper C value the overshoot can be kept small, rise time only minimally degraded, and no heat.
Start with a 1 nF ceramic HV capacitor and go from there through the various ferrite beads in the kit. Short lead lengths to drain and source.
In Europe, I obtained a ferrite bead kit from Murata called "Chip Ferrite Bead BLM series, kit no. EKEM11UA. Of course, if you can convince them you are in R&D and a large series production is planned afterwards, then you are in a better position to obtain a kit.
This does not free you from the obligation to keep the output loop length close to zero.
Eldarion
Quote from: eldarion on October 26, 2007, 08:10:28 PM
As always, thank you for all of the invaluable assistance you have been providing to this group! :) Hopefully we can figure out what is wrong quickly...
Eldarion
EDIT: Maybe the rise/fall times on my gate driver are actually too fast, thus giving rise to the atrocious ringing.
With improper physical layout, it is possible to have too fast transitions. I was not joking when I said your layout must be as if the circuit is operating at 1 GHz.
The only wires should be ones going to the toroid, the driver & switch electronics should have no wires in the switching circuit path. Ground bounce is a big problem is PCB layout of modern digital logic and only good layout can help. If you absolutely must use a wire to connect driver to gate, make it as short as possible and if necessary replace one wire with many insulated ones in parallel (litze). Bob has his reasons for not using litze in the toroid, but these reasons do not apply for hay-wired PCB connections.
I went ahead and added 470 ohms of series resistance to the gate driver output in order to slow down the transition a bit and "shape" the pulse, and the ringing all but disappeared on that primary coil. I have not yet had a chance to try the 470 ohm resistor on the other two primaries.
Am I thinking correctly here? I am assuming that the ringing is going to destroy the effect far faster than a slightly slower rise/fall time on the pulses.
I advise my clients never to use gate resistance, but to combat ringing and RFI legal limits with correct circuit layout. This implies lead length approaching zero.
Hi Earl,
I'm not quite sure what I was thinking when I wrote that edit. Experimenting late at night with no sleep is not a good thing... ::) You are most right, and the gate resistors are now gone. ;)
I do have some other ideas I will try.
Does anyone know of a place to get Dallas/Maxim onewire parts? I was going to order a DS2432 OneWire EEPROM from them, and then noticed the lead time: 22 weeks!!! :o I am using that EEPROM to store settings, and obviously do not want to redesign that portion of the controller.
Thanks!
Eldarion
this is an almost carbon copy of a reply that I made in Ward's thread,
I repost here so Bob has an opportunity to reply without image loading problems.
Hi Ward,
I assume this choke is to keep the radiant energy from shorting to ground via the HV supply.
Two comments:
1- you can always use a resistor is series with the choke.
2- I believe you could also use only a resistor to achieve the same isolation. A 22 Megohm resistor should provide enough isolation.
My suggestion would be to use only several [chip ?] resistors in series. The reasons being that if one should short or get too dusty or dirty or humid, you would still have electrocution protection in case of something stupid happening. The current should be essentially zero, so resistance does not matter. I would use a couple of 1M or 10M SMD chips in series. The distance between total resistance ends should be sufficient to satisfy safety concerns of eventual arc-over. An additional plus is that if the resistance drops any voltage, then you know you have a current leakage somewhere. A series connection of resistors also drops any residual capacitance across the R, 3 Rs in series has 1/3 the capacity of just one resistor.
the choke shown is real nice, but very big. A couple of series SMD resistors has much less volume and will fit into the center of the toroid.
Do not forget that such big chokes while effective at lower frequencies might present a short-circuit at higher frequencies due to inter-turn capacity. There is no such thing as one choke being effective over a broad range of frequencies.
My gut feeling is that series resistors are preferable over an inductance for the following reasons:
1- current limiting against electrocution hazard
2- wider frequency range
3- much smaller volume
One time I had a 220V to 24 VDC switching power supply that had arcing problems because of too close spacing, especially in boat motor rooms (salt vapor in the air). I coated the corresponding area with 5 min epoxy 2-component glue and that solved the problem. A solution, but not really the correct one.
Anything over 50 Volts and 10mA can cause fatal heart fillibration, so safety first. As a teenager, I took 500V between the hands (young brains are not that cautious) and believe me it was not pleasant to have muscle contraction and know I was going to die from electrocution. Only quickly standing up and moving backwards saved my life by pulling the vacuum tube power supply from table onto the floor where it smashed to pieces.
Regards, Earl
All,
I'm rather embarrassed--seems I grew way too trusting with regards to the pulse generator's correctness:
http://www.falconir.com/pics/channel_phasing_OOPS.jpg
I will try to fix this ASAP... :-[
On the bright side, my PCBs came! So I will be stuffing one with parts.
Here is a pic:
http://www.falconir.com/pics/DSC02299.jpg
Eldarion
Further updates on my build will be posted on my thread where they belong, so as not to pollute this thread any further... ;)
Eldarion
Hey there everyone... Sorry, been busy here.
I wrote some simple code for the HexController+ Deluxe. It runs with trouble up to 60 Khz (primarry) with all 8 channels in use. If I drop back to 4 channels then it runs solid up to 90 Khz (primary). The secondary and tertiary are running at precisely 1/2 and 1/4 of the primary frequency, as expected. A little timing glitch pops up on channels 1a and 1b when running in 8 channel mode. I am getting double pulses only on those channels every other pulse, regardless of the frequency setting. I have double, triple, and quadruple checked my code, seems to be a compiler bug. Channels 2a, 2b, 3a,3b,4a, and 4b do not have this pulse anomoly, no matter what frequency I run it at. The double pulses are so close together that it just looks like a pulse that is twice the pulse width of the other pulses. That is until you really open the pulse up on a scope and examine it closely. At first I thought I had a short between channels somewhere, but if that were the case, it would be there when I run other code that pulses all of the channels
The hydroxy gas mode code runs rock solid, but that is at a lot lower in frequency than I would like to get this puppy up to. I really think I'm going to need a faster uC in order to get this up to where I want it, but at least I'm having fun ;-)
I am still seeing a tiny amount of ringing on the unloaded driver outputs. The driver to FET traces are nearly 0.400" long. Longer than I really wanted, but I also wanted to put my MUR410s right at the FET locations. The drivers are bypassed like crazy, with 12 SMD bypass caps surrounding each driver. They are shared where each driver meets the next. I have not installed FETs on this board yet, wanting to get the speed up there first before I waste any FETs.
The HP8116A arrived DOA and smashed control panel. From the packing material and box condition (excellent) it was determined that it had been dropped by some idiot in the shipping dept of Silicon Salvage in CA. They did a partial refund, but I'm still not able to use it yet. I about had a heart attack when the eBay auction for my old hydroxy version HexController closed today at over $1000! Looks like I'll be able to get some better test EQ from eBay ;-)
@eldarion
I was wondering if the waveforms being produced by your board were actually coming out like it was reporting. I know in the case of my new HexController+ Deluxe, measured waveforms were slightly different from what code calculations were predicting. I had to add compensation code to correct it. For example, if set for 42.800 Khz primary, measured output was rock solid, but at 42.794 Khz. the older HexController was even more off, as it would read 42.774 Khz. It required more compensation. Be sure to let us know how it works out.
Bob