Author Topic: No current flowing through half bridge (kaizer sstc 3)  (Read 844 times)

Offline davekni

  • High Voltage Engineer
  • ****
  • Posts: 296
  • Karma: +18/-0
  • Physicist, engineer (electronic), and hobbiest
    • View Profile
Re: No current flowing through half bridge (kaizer sstc 3)
« Reply #20 on: March 26, 2020, 05:18:04 AM »
The 0.1uF capacitor is in the gate drive circuit.  The relevant capacitance here is U2-1, the antenna connection.  CD40106 data sheet lists 5pF typical input capacitance.  I can't find capacitance curves for 1N60 diodes.  The antenna may add another 5pF - depends on how long it is and what other conductive parts it gets close to.  So, the capacitance to use in calculating self-oscillation is around 10 to 15pF.  It is just the first schmitt-trigger inverter stage involved in the self-oscillation, so only U2-1 and U2-2.  You can test self-oscillation without anything else powered up.
David Knierim

Offline prabhatkumar

  • High Voltage Enthusiast
  • *
  • Posts: 47
  • Karma: +0/-0
    • View Profile
Re: No current flowing through half bridge (kaizer sstc 3)
« Reply #21 on: March 26, 2020, 07:09:14 AM »
Well I did some hit and trial and came to conclusion that 200 k resistor shall do the trick i.e the schmitt trigger shall oscillate somewhere around 180 kHz ( at the gates of the mosfets )and advised by you that the oscillation of the schmitt trigger shall be less than the self resonating frequency of the coil ( which is. 240khz here). So could you explain me how does the feedback from the antennae later take over . And won't this resistor interfere with the normal oscillation from the feedback. Thanks
And another thing which I have observed is that the ucc chips start getting warm now which is expected but then one of the ucc chips gets a bit more heated than other in this case the bottom ucc is more heated and I have no idea why . Is that normal . My understanding here is that the top ucc has a resistor in series to the gdt and that 0.1 uF cap also. But then bottom ucc is directly connected to the gdt. So is that causing it or just a matter of coincidence. I have also added a small heatsink to the ucc to make them cooler as I don't have a interrupter working .
And now could you also tell me the procedure I should follow for successful first light now please .
Also how important is grounding of the base of secondary. I have connected it to the ground (earthing )of the house wiring . Is that right ??
« Last Edit: March 26, 2020, 02:08:48 PM by prabhatkumar »

Offline davekni

  • High Voltage Engineer
  • ****
  • Posts: 296
  • Karma: +18/-0
  • Physicist, engineer (electronic), and hobbiest
    • View Profile
Re: No current flowing through half bridge (kaizer sstc 3)
« Reply #22 on: March 26, 2020, 07:26:46 PM »
Great!  Adding the resistor actually increases sensitivity to antenna feedback, as it charges the antenna voltage most of the way for each half-cycle, so only a little extra charge from the antenna is needed for each transition.  Once the secondary voltage ramps up, the antenna feedback current will be much larger than the resistor current, so the resistor will have little effect.

It's not surprising that the UCC chips warm up, as they are running continuously now.  No reason I know for one to heat more than the other.  Likely one happens to have a bit higher drive strength so runs a bit cooler.  The only load difference would be parasitic wiring capacitance, not significant for heating.  Heat-sinking is a good idea, since most SSTC designs don't run at 100% duty cycle.  You won't be able to use an interrupter without the enable pins working.

There are many variations for grounding.  My preference is to lay aluminum foil or sheets or screen on the floor/ground, then wire the secondary ground to the foil and to the power line ground.  Grounding details are more important for SGTCs and DRSSTCs, as they have high peak currents.  You should be fine with just the line ground wire for an SSTC.  (Thinking back, that's all I used for my SSTC.  Haven't had that out in years.)

I've always used current feedback, so hopefully you've found other information on just how close to place the antenna to the secondary to be safe from arcing over.  To start up, place the antenna near the secondary however is typical, apply gate-drive power, then initially some low half-bridge power, perhaps 30V.  With the self-oscillation, 30V bus is likely enough to get it to sync. up.  You can see with the scope if gate-drive (or half-bridge secondary) frequency jumps up to 240kHz.  If not, you can try raising the bus voltage further, or drop the self-oscillation resistor to ~160k to get closer to 240kHz starting point.

Do you have any current-limiting in your bus supply?  A current-limited bench supply would be great for start-up testing.  If running directly from a variac, adding an incandescent light bulb in series between the variac and rectifier bridge is a good current-limit option.  The half-bridge current will be low until the antenna feedback locks the frequency.  Current will jump up when it locks.  Running continuously may draw too much current to allow reaching your intended bus voltage before current gets too high.  Check gate-drive phasing before approaching full power.
David Knierim

Offline prabhatkumar

  • High Voltage Enthusiast
  • *
  • Posts: 47
  • Karma: +0/-0
    • View Profile
Re: No current flowing through half bridge (kaizer sstc 3)
« Reply #23 on: March 26, 2020, 07:44:05 PM »
Hey davekni thanks for the reply. I am looking forward to get my tesla coil working as soon as possible and i will sticking to your advice. As there is complete corona lock down where I live (INDIA),  I dont have access to a variac which is there in my college lab, so for now i will power it with bench power supply which is current limited and handle 60v 5 amps. And i have read about the antennae feedback but I am not very confident about it, I will power the driver side first and see if the gates are receiving proper signals . Also how do you confirm whether the phasing of the primary coil is correct or not. Because the bridge will not draw significant current unless a high enough voltage is reached and till it might be too late to correct the phasing, so could you help me with that. And by hot I mean one of the chips reach 51 degree Celsius within minutes and settles there and increases slowly, while the other reaches 55 degree Celsius and increases slowly. Also I am attaching the waveform at the outputs of the ucc chips. But there is something weird to it. The ucc chip which has the resistor and capacitor in series to its output shows a slightly different rising and falling curve(there are weird peaks and sags in it ) than the other ucc chip. And the irony is that the other ucc chip which doesn't have resistor and capacitor to its output shows a good curve but is getting slightly hotter.
« Last Edit: March 26, 2020, 07:47:53 PM by prabhatkumar »

Offline davekni

  • High Voltage Engineer
  • ****
  • Posts: 296
  • Karma: +18/-0
  • Physicist, engineer (electronic), and hobbiest
    • View Profile
Re: No current flowing through half bridge (kaizer sstc 3)
« Reply #24 on: March 27, 2020, 01:49:23 AM »
Your 60V 5A supply should be perfect for bring up this SSTC!

Coarse phasing (180 degrees or not) is easiest by trying both ways to see which one locks frequency.  Once the coarse phasing is correct and the coil is running with feedback, I suggest measuring the more subtle phase shift.  Scope the H-Bridge output with one probe and use the other probe as an antenna - just hanging in the air somewhere around the coil.  Ideally the H-Bridge output switches at or just before the peaks of the top-load voltage (which the floating scope probe is picking up).  Leave the floating probe separate from the feedback antenna to avoid changing behavior.

Not having any personal experience with antenna feedback, it seems to me that it will end up with more phase lag than ideal, with the H-Bridge output switching after the top-load voltage peak time.  That may still be fine as long as it's within 30 degrees or so.  Phasing might be better with the self-oscillation frequency set at or slightly above resonance - opposite what I'd said earlier.  Since I haven't built an antenna system myself, you'll need to experiment.  Try 150k or even 130k to see what it does to phasing.  At 60V and a 5A limit, your H-Bridge parts shouldn't be at much risk due to any phasing errors.

Concerning the UCC output waveform shape, my guess is that the upper (green trace) UCC chip happens to be slightly faster (shorter delay time) than the other UCC chip.  It switches with a fast edge, then is pulled back a bit by the increased load current when the other UCC chip switches.  As to one being warmer, I don't have any new guesses.  55C doesn't sound problematic.  Is that with the heatsink you added?  Temperature will go up a bit further once the frequency locks to 240kHz.
David Knierim

Offline prabhatkumar

  • High Voltage Enthusiast
  • *
  • Posts: 47
  • Karma: +0/-0
    • View Profile
Re: No current flowing through half bridge (kaizer sstc 3)
« Reply #25 on: March 27, 2020, 08:08:13 PM »
Thanks for the reply davekni. Well this is the first time I heard about the phasing being so critical . In this regard only , my doubt is that will the coil draw no current if the primary is the other way round.( Which I think will not harm any anything , just flip it ) . But does the bridge start drawing current once it locks in at lower voltages like 15 volts or so ?? At this stage I am not worried about the subtle phase difference of the switching of the bridge and the antennae feedback from the coil itself. And the temp of the chips are without the heatsink. The last time I powered my bridge at 30volts , I don't know how the power supply which was supplying zero current suddenly got into current limit mode ( means something shorted obviously ) . So should I not worry about this and continue with the testing of the coil ?
« Last Edit: March 27, 2020, 08:13:22 PM by prabhatkumar »

Offline ZakW

  • High Voltage Enthusiast
  • *
  • Posts: 10
  • Karma: +0/-0
    • View Profile
Re: No current flowing through half bridge (kaizer sstc 3)
« Reply #26 on: March 27, 2020, 10:33:07 PM »
Hey davekni thanks for the reply. I am looking forward to get my tesla coil working as soon as possible and i will sticking to your advice. As there is complete corona lock down where I live (INDIA),  I dont have access to a variac which is there in my college lab, so for now i will power it with bench power supply which is current limited and handle 60v 5 amps. And i have read about the antennae feedback but I am not very confident about it, I will power the driver side first and see if the gates are receiving proper signals . Also how do you confirm whether the phasing of the primary coil is correct or not. Because the bridge will not draw significant current unless a high enough voltage is reached and till it might be too late to correct the phasing, so could you help me with that. And by hot I mean one of the chips reach 51 degree Celsius within minutes and settles there and increases slowly, while the other reaches 55 degree Celsius and increases slowly. Also I am attaching the waveform at the outputs of the ucc chips. But there is something weird to it. The ucc chip which has the resistor and capacitor in series to its output shows a slightly different rising and falling curve(there are weird peaks and sags in it ) than the other ucc chip. And the irony is that the other ucc chip which doesn't have resistor and capacitor to its output shows a good curve but is getting slightly hotter.

Hello prabhatkumar,

I was wondering if your scope probes are correctly compensated? They have a little adjustment screw on them. The wave form looks a lot like when they are under-compensated.

https://sound-au.com/articles/oscope-f13.gif

Offline davekni

  • High Voltage Engineer
  • ****
  • Posts: 296
  • Karma: +18/-0
  • Physicist, engineer (electronic), and hobbiest
    • View Profile
Re: No current flowing through half bridge (kaizer sstc 3)
« Reply #27 on: March 28, 2020, 12:59:53 AM »
Yes, the fine phasing isn't that critical for SSTCs using FETs for the bridge.  It is critical for high-current DRSSTCs using IGBTs.  Still, efficiency is better with good phasing, and bridge layout (low inductance) is less critical with good phasing.

The gate-drive waveforms do look a lot like scope probe mis-adjustment.  However, the time scale is wrong for scope probe compensation.  I think your traces are likely accurate plots of UCC chip outputs.  They change rapidly until the voltage where they can't supply any more current to the gate series resistors.  Then they finish slewing as the gate capacitance is charged.

The bus supply should draw some current even if not sync'ed given the self-oscillation resistor addition - more than 18mA.  When sync'ed, it will increase several times.  At 15Vbus, the self-oscillation frequency will likely need to be adjusted closer to resonance (closer to 240kHz) to get sync'ing.  It should be possible to sync at 15V with good self-oscillation frequency.

The only reason I can imagine for FET frying at 30V is that there was some spike in gate-drive that over-voltaged the gates.  It's easy to get 24V from that gate-drive circuit, but that's generally not enough to fry FETs.  It would require a series resonance of the 0.1uF and gate-drive transformer inductance to go over 24V.  Perhaps somehow the antenna picked up the gate voltage and resonated at that frequency.  You could add a bidirectional TVS diode or back-to-back zener diodes from gate-to-emitter on each FET.  That would protect them from such gate-drive resonances.

Beyond adding FET gate voltage clamps, I don't know what other option you have other than starting to power it up.  I'd start with the current limit set low, perhaps 0.5 to 1A, just to be extra cautious.

Good luck!
David Knierim

Offline prabhatkumar

  • High Voltage Enthusiast
  • *
  • Posts: 47
  • Karma: +0/-0
    • View Profile
Re: No current flowing through half bridge (kaizer sstc 3)
« Reply #28 on: March 28, 2020, 07:05:29 AM »
Well when I was just about to attach the Tesla coil as a load, I tried testing with a 10 ohm resistor as load . Something really bad happened that put me back 2-3 days again. Before I continue , I would like to inform that MY OSCILLOSCOPE IS NOT MAINS-EARTH REFERENCED , I TAPED A PIECE OF TAPE ON THE EARTHING PIN, WHICH ISNT THE BEST WAY TO DO IT.  So now when I attached the bus volatge to the bridge , everything looked flawless , the gate waveforms were very close to retangualr wave , etc. But when I increased the supply volatge to 30 volts or something , I don't know how the supply voltage Rose to 44 volts , even though my supply maximum is 30 volts. Well I thought maybe that was due to extra length of antennae just kept floating in air which injected high frequency noise into the supply. But when I remove the ground clip of OSCILLOSCOPE probe from the source terminal , the supply seems to back on the 30 volt mark. Well my scope is floating then how does it inject noise through the ground wire to the supply.??
Second most important observation, as soon as I remove the ground clip from the source terminal the driver section seems to draw very high current from its current source ( 12 volt battery so that it's in no way connected to the supply ) , the current rose to 620 mA. !! Well under normal condtions , the current is within the 200mA mark always till now. And the weird thing is when the driver drew that high current the ucc chips got nasty hot ( I think it would have burned if I didn't disconnect the power ) and the current to the load from the supply i.e when the ground clip is connected , the load drew 700-800 mA from the supply and when the load is removed , then it drew only 100 mA and around 600 mA from the driver supply was going .
My understanding here is that the ucc basically themselves supply the high current draw of the load themselves rather than the supply itself.
And also when the Slayer exciter is running i.e the feedback from the antennae dominates over the schmitt trigger oscillator , the driver board is back with is nominal current draw within 200 mA. What's causing all this please explain I am going absolutely crazy with these things happening to me.
Another thing is that when I connect the battery negative to earth ground , everything becomes normal but now when I connect my oscillsocpe probe then voltages again shoot up high to 44 v.
Now please tell me which thing is right to do i.e whether I let the ucc draw the high current , or there is something mysterious happening which I am not aware of . Thanks !!
« Last Edit: March 28, 2020, 11:22:31 AM by prabhatkumar »

Offline davekni

  • High Voltage Engineer
  • ****
  • Posts: 296
  • Karma: +18/-0
  • Physicist, engineer (electronic), and hobbiest
    • View Profile
Re: No current flowing through half bridge (kaizer sstc 3)
« Reply #29 on: March 28, 2020, 05:54:40 PM »
That's lots of symptoms.  I certainly won't be able to tell remotely exactly what happened.

"Floating" scopes or other equipment aren't completely floating.  There's always capacitance to the line neutral and hot wires in the scope's power supply.  The scope is likely injecting more noise when floating.  I recommend keeping your scope grounded, and keeping the driver circuit grounded.  During this initial bring-up with a bench power supply, ground the bridge negative supply as well.  With ungrounded circuitry, part of the signal the antenna sees is the noise on its local "ground" reference, the negative driver supply terminal.

(Do you happen to live close to a commercial radio broadcaster?  As a kid we lived about 1km from an AM radio station.  Any sort of antenna picked up obvious amounts of that ~1MHz signal.)

Especially without the secondary in place, the antenna may be picking up noise from any source, including floating "grounds".  The most problematic may be if the gate wiring is long enough and/or close enough to the antenna that gate-drive becomes the feedback.  There's nothing in that circuit to prevent oscillation at high frequency, which would likely happen if picking up feedback from the gate drive wires.  If you ground everything, at least that eliminates some of the noise sources, so it would be easier to see any high-frequency oscillation.

During normal operation, the high secondary voltage dominates over any other noise sources the antenna may pick up.  Testing without the secondary can still be possible as long as things are grounded and the gate-drive wiring is shielded from the antenna.

Concerning 44V, that may be a digital meter getting confused by high-frequency noise.  Cheap meters have little shielding internally.  Usually I see random quickly-changing values in such circumstances rather than voltage errors, but I have occasionally seen just an offset as you are seeing.
David Knierim

Offline prabhatkumar

  • High Voltage Enthusiast
  • *
  • Posts: 47
  • Karma: +0/-0
    • View Profile
Re: No current flowing through half bridge (kaizer sstc 3)
« Reply #30 on: March 28, 2020, 06:30:27 PM »
Well thanks for the reply and going through the wall of text I have written out there. On a positive note , the coil is working now . Also regarding radio/AM station , I doubt that there is any near my house. I live in a seaside building , there is completely sea on one side and other is dense town so I highly doubt they are going to install radio station there.
And for trying grounding of each and everything on the driver board and the scope itself , I have a doubt itself , if I connect my grounded scope to the grounded driver board , there won't be any explosion right ??
And before trying the issue on ambient noise which the antennae might be picking up , I need to verify this with a proper differential probe that the issue is background noise only .
And coming to how I got it to work , first of all I reduced the diameter of the primary ( Initially to come close the coupling given by Java TC, I Made the primary diameter very big and also positioned the secondary coil beginning just above where the primary ends ). By this theoritically  I came close to the recommended coupling . But now after seeing everyone's design I realised that this may cause the driver not to couple properly and link with the secondary leakage and hence not turn the driver on . So I made a new primary with diameter very slightly bigger than the secondary and positioned the secondary directly without any elevation this time. And now just by luck and a trial or two with the phasing, the coil magically started producing arcs. I was damn happy . And now the supply voltage directly goes to 44 volt mark again once I cross the 17 volt mark of my supply ( that's where the relay clicks for the last highest volatge tap selection). But I won't mind it now as I will power it with a beefy 27 volt transformer which can atleast give 5 amps maybe( I don't know the exact ratings as I got it as a salvage for a low price at old metal and paper mart.).
Also I have taken a couple of waveforms for the phase lag you talked about (davekni). But phase lag between which to two waves is of interest to us here ( just tell me the where do I connect my probes so that I upload the waveforms if you are interested in telling me :)
I will update this thread maybe next when I see another issue 😬 and also when I get a hands on a proper differential probe ( which won't happen soon as it is there in my college lab and everything is shut here due to Corona lockdown ). Thanks again davekni and to everyone else who kindly replied to this noob
« Last Edit: March 28, 2020, 06:34:42 PM by prabhatkumar »

Offline davekni

  • High Voltage Engineer
  • ****
  • Posts: 296
  • Karma: +18/-0
  • Physicist, engineer (electronic), and hobbiest
    • View Profile
Re: No current flowing through half bridge (kaizer sstc 3)
« Reply #31 on: March 28, 2020, 07:06:19 PM »
Yes, the radio station thought was unlikely for you.  An AM station antenna would be large, so obvious to see.  It was just childhood memories for me.

As long as it's only the "ground" nodes being grounded, not literally "everything", then nothing will blow up.  The scope should be grounded, the driver ground (pins 4 and 5 of the UCC chips etc.) should be grounded, and the bridge negative supply (negative side of C12) should be grounded.  Then the scope probe ground can be clipped to either the driver or bridge grounds for measuring voltages.  You cannot connect the scope across two non-grounded nodes, such as measuring the voltage across C4 of the driver, because that would be grounding one side of C4.  Always measure voltages relative to ground, with the scope probe ground clip on one of the ground nodes.  (Of course, for the bridge, this works only when using a bench supply or transformer, not when powered directly from line voltage.  Once running on line voltage, don't ground the negative side of C12, and don't clip the scope probe ground to anything on the bridge circuitry.  Leave the driver grounded even with direct line voltage on the bridge.)

It sounds to me like your power supply has an internal failure causing the 44V jump.  Might still be usable though.  If its current limit still functions, that would add a bit of protection over using a transformer directly, even if the voltage isn't fully adjustable.  The supply's internal failure might make current limit non-functional as well.

Yes, higher coupling is generally good for an SSTC, until the point where the primary gets so close to the secondary that voltage starts arcs across the gap.  Look in the dark at the bottom of the secondary and at the primary to see if there's significant corona discharge.  That indicates you are close to a problem there.

As you've found, low coupling doesn't generate enough secondary voltage to couple into the antenna and start oscillation (or lock oscillation to the resonant frequency in this case with self-oscillation).

For phase measurement, here's what I was asking in reply 24:  "Coarse phasing (180 degrees or not) is easiest by trying both ways to see which one locks frequency.  Once the coarse phasing is correct and the coil is running with feedback, I suggest measuring the more subtle phase shift.  Scope the H-Bridge output with one probe and use the other probe as an antenna - just hanging in the air somewhere around the coil.  Ideally the H-Bridge output switches at or just before the peaks of the top-load voltage (which the floating scope probe is picking up).  Leave the floating probe separate from the feedback antenna to avoid changing behavior."

Now that you are running, phase measurement isn't critical.  I am personally interested in the phase measurement, however, not having any experience myself with antenna feedback.  (Antennas seem to likely to pick up other stray signals, so I've always used current feedback.)  Thank you for your willingness to provide the traces!
David Knierim

Offline prabhatkumar

  • High Voltage Enthusiast
  • *
  • Posts: 47
  • Karma: +0/-0
    • View Profile
Re: No current flowing through half bridge (kaizer sstc 3)
« Reply #32 on: March 28, 2020, 07:33:57 PM »
Thanks davekni for letting me know a lot on scope grounding because I was very confused till now. But still I have doubt on that. You told me to scope the output of the h bridge. That should be done with the scope grounded or non grounded . And also the output of the h bridge should be something close to a sine wave of only the current is the primary is a sine wave. If the volatge of the h bridge output is a sine wave then probing the output with scope grounded will lead to an explosion right . Because when the sine wave goes into the negative half then the other terminal ( so called neutral ) gets energised and scope lead connected here will directly lead to an explosion if the scope is grounded . If this logic is correct ,( which mostly isn't ) , then we shouldn't be able to measure any ac wave with a scope eg speaker pins or any other ac wave. So where  I am going wrong here. Do you have any resource that describes the scope measurement with respect to ground and other grounding details . Or if you are extra nice then you could only write over here :)

Also about the power supply. It's a very simple old linear type power supply with simple analog stuff and nothing fancy in there . You can Google hy3005 and you get flooded with hundreds of power supplies with similar structure and just sold by different brand names. Actually you are correct about it malfunctioning. When the supply goes crazy and touches the 44 volt mark or even above 35 volt ( which happens automatically ) I lose the current limit function and until the I bring the knob to very beginning ( i.e zero current ). The supply has grounding pins on front so will shorting the ground to negative help here to reduce the noise ??
And just telling my supply works absolutely fine when powering anything apart from the Tesla coil. (. Current limit also functions every well then ).
« Last Edit: March 28, 2020, 07:53:40 PM by prabhatkumar »

Offline davekni

  • High Voltage Engineer
  • ****
  • Posts: 296
  • Karma: +18/-0
  • Physicist, engineer (electronic), and hobbiest
    • View Profile
Re: No current flowing through half bridge (kaizer sstc 3)
« Reply #33 on: March 29, 2020, 12:43:24 AM »
For grounding, I'll emphasize a line from my last answer: "  (Of course, for the bridge, this works only when using a bench supply or transformer, not when powered directly from line voltage.  Once running on line voltage, don't ground the negative side of C12, and don't clip the scope probe ground to anything on the bridge circuitry.  Leave the driver grounded even with direct line voltage on the bridge.)"

As long as you are running from your hy3005 supply or a transformer, ground the negative side of C12, and clip the scope probe ground to that node as well.  The ground terminal of your hy3005 supply is a good place to ground the bridge.  Don't do that once running directly from line power!  For scoping any circuit, it's best to have the scope probe ground clip connected to the ground node of the circuit you are probing.  If the circuit doesn't have a ground node, such as the h-bridge when connected to line voltage, then a differential probe is needed.  (Floating the scope ground can work instead, but only when the probe's ground lead is connected to a low-impedance circuit node, such as the negative side of C12, where injected noise won't be a problem.  Floating scope ground will now have rectified line voltage, so is a shock hazard.  And the other scope probe's ground clip will be at the same line voltage.  So, don't scope any other signals at the same time - only one signal when using floating ground.  In general, floating scope ground is risky, so I recommend not floating your scope ground.)

Yes, differential probes are useful for scoping many things, such as speaker terminals as you mentioned.  Old amplifiers usually had one speaker terminal at ground and drove the other with the audio signal.  Many amplifiers today drive both sides of the speaker with opposite-polarity audio signals.  So you shouldn't connect either speaker terminal to the scope ground.  For most audio amplifiers, the speaker signal on either side is sufficient for probing, because the other side will be an inverted version of the same waveform.  If you need to scope across the speaker, either use a differential probe, or use both scope probes and the waveform-subtract math function of the scope.  That does the same thing as a differential probe, although not quite as accurately as a good differential probe.

The H-Bridge output should be a square wave with a frequency of 240kHz (your resonant frequency).  It's always connected to either the negative side of C12 or to the positive side of C12.  The phase information I'm interested in is when the square wave edges are timed relative to the secondary high-voltage sine wave.

When the bridge is powered directly from line voltage, then there will be some rectified 50Hz sine wave signal on top of the much higher frequency square wave signal.  Since the frequencies are so different, scoping the bridge output can be useful even when line-powered.  (The scope probe ground needs to be left unconnected when probing a line-powered bridge!)

Sounds like the high-frequency signals of your SSTC are confusing the power supply circuitry.  Connecting the supply negative output to the supply ground terminal may fix that issue, making the supply behave correctly.

If I missed answering anything, please ask again.
David Knierim

High Voltage Forum

Re: No current flowing through half bridge (kaizer sstc 3)
« Reply #33 on: March 29, 2020, 12:43:24 AM »

 


* Recent Topics and Posts

post Re: GDT keeps on killing IGBTs
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
Today at 04:15:12 AM
post Re: GDT keeps on killing IGBTs
[Dual Resonant Solid State Tesla coils (DRSSTC)]
ritaismyconscience
Today at 01:05:28 AM
post Re: TVS diode selection for 400v transistor
[Electronic Circuits]
SteveN87
Today at 12:53:15 AM
post Re: GDT keeps on killing IGBTs
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
April 07, 2020, 10:54:57 PM
post Re: GDT keeps on killing IGBTs
[Dual Resonant Solid State Tesla coils (DRSSTC)]
ritaismyconscience
April 07, 2020, 10:24:16 PM
post Re: Class E SSTC Topology
[Solid State Tesla Coils (SSTC)]
ZakW
April 07, 2020, 09:22:16 PM
post Re: Class E SSTC Topology
[Solid State Tesla Coils (SSTC)]
johnf
April 07, 2020, 09:04:34 PM
post Re: Class E SSTC Topology
[Solid State Tesla Coils (SSTC)]
ZakW
April 07, 2020, 08:48:01 PM
post Re: Class E SSTC Topology
[Solid State Tesla Coils (SSTC)]
Weston
April 07, 2020, 08:15:43 PM
post Re: TVS diode selection for 400v transistor
[Electronic Circuits]
John123
April 07, 2020, 06:23:47 PM
post Re: Where is plasma globe arc arcing to?
[Beginners]
John123
April 07, 2020, 05:59:09 PM
post Re: Where is plasma globe arc arcing to?
[Beginners]
alan sailer
April 07, 2020, 04:30:26 PM
post Re: Powerful easy to build MIDI Interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
Max
April 07, 2020, 01:10:30 PM
post Re: TVS diode selection for 400v transistor
[Electronic Circuits]
SteveN87
April 07, 2020, 12:44:56 PM
post Re: Where is plasma globe arc arcing to?
[Beginners]
John123
April 07, 2020, 07:05:30 AM
post Re: Where is plasma globe arc arcing to?
[Beginners]
Jun
April 07, 2020, 06:40:02 AM
post Re: Class E SSTC Topology
[Solid State Tesla Coils (SSTC)]
ZakW
April 07, 2020, 05:07:31 AM
post Re: TVS diode selection for 400v transistor
[Electronic Circuits]
John123
April 07, 2020, 03:38:12 AM
post Re: TVS diode selection for 400v transistor
[Electronic Circuits]
SteveN87
April 07, 2020, 03:21:55 AM
post Re: TVS diode selection for 400v transistor
[Electronic Circuits]
John123
April 07, 2020, 02:59:28 AM
post Re: TVS diode selection for 400v transistor
[Electronic Circuits]
davekni
April 07, 2020, 02:52:19 AM
post Re: Small DIY plasma globe using ZVS oscillator
[Transformer (Ferrite Core)]
John123
April 07, 2020, 02:29:21 AM
post Re: Where is plasma globe arc arcing to?
[Beginners]
John123
April 07, 2020, 02:21:55 AM
post Re: TVS diode selection for 400v transistor
[Electronic Circuits]
John123
April 07, 2020, 02:00:26 AM
post Re: TVS diode selection for 400v transistor
[Electronic Circuits]
SteveN87
April 07, 2020, 01:25:47 AM
post Re: TVS diode selection for 400v transistor
[Electronic Circuits]
John123
April 07, 2020, 12:38:59 AM
post Re: TVS diode selection for 400v transistor
[Electronic Circuits]
petespaco
April 07, 2020, 12:13:11 AM
post Re: Corona lockdown thread, tell about your situation
[General Chat]
John123
April 06, 2020, 10:07:59 PM
post Re: TVS diode selection for 400v transistor
[Electronic Circuits]
davekni
April 06, 2020, 10:07:11 PM
post Re: Corona lockdown thread, tell about your situation
[General Chat]
Mads Barnkob
April 06, 2020, 09:57:29 PM
post Re: TVS diode selection for 400v transistor
[Electronic Circuits]
John123
April 06, 2020, 08:04:52 PM
post Re: Power MOSFETs with fast recovery body diodes
[Electronic Circuits]
John123
April 06, 2020, 07:49:30 PM
post Re: Where is plasma globe arc arcing to?
[Beginners]
davekni
April 06, 2020, 06:30:24 PM
post Re: GDT keeps on killing IGBTs
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
April 06, 2020, 06:23:27 PM
post Where is plasma globe arc arcing to?
[Beginners]
Jun
April 06, 2020, 02:10:18 PM
post Re: Interuppter code help for sstc (LONEOCEANS SSTC2 )
[Solid State Tesla Coils (SSTC)]
Max
April 06, 2020, 10:21:47 AM
post Journey to a small stand alone CW signal synthesizer
[Radio Frequency]
Da_Stier
April 06, 2020, 09:56:07 AM
post Re: GDT keeps on killing IGBTs
[Dual Resonant Solid State Tesla coils (DRSSTC)]
ritaismyconscience
April 06, 2020, 05:09:29 AM
post Re: Class E SSTC Topology
[Solid State Tesla Coils (SSTC)]
ZakW
April 06, 2020, 02:26:28 AM
post Re: Skm100 coil
[Dual Resonant Solid State Tesla coils (DRSSTC)]
oneKone
April 06, 2020, 02:16:56 AM
post Re: Portable Q(uarantine)CW Tesla Coil
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
April 06, 2020, 12:43:50 AM
post Portable Q(uarantine)CW Tesla Coil
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Weston
April 05, 2020, 10:47:07 PM
post Re: Unconventional 3kW SSTC
[Solid State Tesla Coils (SSTC)]
davekni
April 05, 2020, 10:46:48 PM
post Re: Interuppter code help for sstc (LONEOCEANS SSTC2 )
[Solid State Tesla Coils (SSTC)]
Max
April 05, 2020, 10:09:40 PM
post Re: Interuppter code help for sstc (LONEOCEANS SSTC2 )
[Solid State Tesla Coils (SSTC)]
ritaismyconscience
April 05, 2020, 09:55:33 PM
post Re: Royer oscillator (ZVS) driven Jacob's ladder, E80 core transformer
[Transformer (Ferrite Core)]
davekni
April 05, 2020, 06:53:57 PM
post Re: Corona lockdown thread, tell about your situation
[General Chat]
Uspring
April 05, 2020, 06:18:50 PM
post Interuppter code help for sstc (LONEOCEANS SSTC2 )
[Solid State Tesla Coils (SSTC)]
prabhatkumar
April 05, 2020, 05:20:57 PM
post Optical flatness inspection
[Light, Lasers and Optics]
klugesmith
April 05, 2020, 08:20:08 AM
post Re: Corona lockdown thread, tell about your situation
[General Chat]
klugesmith
April 05, 2020, 07:49:27 AM

Sitemap 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 
SimplePortal 2.3.6 © 2008-2014, SimplePortal