Author Topic: Bridge failure - which went first, board or IGBT?  (Read 465 times)

Offline GrantV

  • High Voltage Experimenter
  • **
  • Posts: 70
  • Karma: +3/-0
    • View Profile
Bridge failure - which went first, board or IGBT?
« on: September 01, 2022, 10:31:12 AM »
Greetings and salutations  8)

The last time I ran my coil I overdid things slightly and was rewarded with the usual flash and bang, which I assumed at the time meant that I had blown an IGBT.

Testing the bridge, I have indeed lost 3 IGBT's, however, unlike the last time that I blew an IGBT, this time none have any physical damage to their casings.

I am attaching photos of my board showing that the tracks off Q4 (full bridge) on both the collector and emitter have been vaporised.

My question is, could this have been a board failure due to an overcurrent/overvoltage/overbps, or, would the failure of the IGBT have caused the board damage?

Secondary question: My coil runs beautifully at very high bps (1500 to 1800) and when it blew, I was likely pushing the bps past 1800. Could this have caused the failure, or, is high bps ok as long as voltage and current are within limits?

Thanks for your comments in advance :-)
Grant


Offline Mike

  • High Voltage Enthusiast
  • *
  • Posts: 40
  • Karma: +3/-0
    • View Profile
Re: Bridge failure - which went first, board or IGBT?
« Reply #1 on: September 01, 2022, 01:21:56 PM »
I've seen identical failures on my bridge. I can't see a way that a PCB failure would cause the IGBT to fail. When the PCB fails it becomes an open circuit and prevents further current from flowing. When the IGBT fails however they normal fail short circuit. In this case there's nothing to stop very high currents flowing which will destroy the PCB.

As for your high repetition rate question, higher BPS means higher duty cycle (assuming you maintain the same on time). This results in the IGBTs heating up more. From here multiple things can go wrong. You could exceed the ability of the part to transfer the energy to the heatsink causing failure. The other thing that changes when you heat up the IGBT is the turn on and more importantly turn off delay increase. This can cause your zero current switching to be further from ideal causing more heating and can ultimately result in shoot through which at elevated temperatures especially, tends to be fatal for the IGBTs.

Offline davekni

  • High Voltage Expert
  • ******
  • Posts: 1791
  • Karma: +88/-1
  • Physicist, engineer (electronic), and hobbiest
    • View Profile
Re: Bridge failure - which went first, board or IGBT?
« Reply #2 on: September 02, 2022, 05:24:10 AM »
Quote
I've seen identical failures on my bridge. I can't see a way that a PCB failure would cause the IGBT to fail. When the PCB fails it becomes an open circuit and prevents further current from flowing. When the IGBT fails however they normal fail short circuit. In this case there's nothing to stop very high currents flowing which will destroy the PCB.

As for your high repetition rate question, higher BPS means higher duty cycle (assuming you maintain the same on time). This results in the IGBTs heating up more. From here multiple things can go wrong. You could exceed the ability of the part to transfer the energy to the heatsink causing failure. The other thing that changes when you heat up the IGBT is the turn on and more importantly turn off delay increase. This can cause your zero current switching to be further from ideal causing more heating and can ultimately result in shoot through which at elevated temperatures especially, tends to be fatal for the IGBTs.
Great answer!  Probably clearer than what I would have written.
David Knierim

Offline GrantV

  • High Voltage Experimenter
  • **
  • Posts: 70
  • Karma: +3/-0
    • View Profile
Re: Bridge failure - which went first, board or IGBT?
« Reply #3 on: September 04, 2022, 04:14:43 PM »
I've seen identical failures on my bridge. I can't see a way that a PCB failure would cause the IGBT to fail. When the PCB fails it becomes an open circuit and prevents further current from flowing. When the IGBT fails however they normal fail short circuit. In this case there's nothing to stop very high currents flowing which will destroy the PCB.

As for your high repetition rate question, higher BPS means higher duty cycle (assuming you maintain the same on time). This results in the IGBTs heating up more. From here multiple things can go wrong. You could exceed the ability of the part to transfer the energy to the heatsink causing failure. The other thing that changes when you heat up the IGBT is the turn on and more importantly turn off delay increase. This can cause your zero current switching to be further from ideal causing more heating and can ultimately result in shoot through which at elevated temperatures especially, tends to be fatal for the IGBTs.

Hi Mike, thanks for that! It does of course make sense that it was the IGBT's that went before the board, I just wanted to throw it out there only because I had found no physical damage to them at all, and there are always lessons to be learned :-)

Thanks also for your answer on the repitition rate. As I am using my own digital ucontroller driven interrupter, it does reduce the on time in track with the increasing bps thus I can never exceed my set max duty cycle. ie. if duty set at 10% bps=200 pw=500 but at bps of 2000 the pulse width will have droped down to just 50usec. Thus, I figured I was relatively in the clear to push the repitition rate higher than 'usual' :-) ?


Offline davekni

  • High Voltage Expert
  • ******
  • Posts: 1791
  • Karma: +88/-1
  • Physicist, engineer (electronic), and hobbiest
    • View Profile
Re: Bridge failure - which went first, board or IGBT?
« Reply #4 on: September 04, 2022, 07:34:06 PM »
Quote
Thanks also for your answer on the repitition rate. As I am using my own digital ucontroller driven interrupter, it does reduce the on time in track with the increasing bps thus I can never exceed my set max duty cycle. ie. if duty set at 10% bps=200 pw=500 but at bps of 2000 the pulse width will have droped down to just 50usec. Thus, I figured I was relatively in the clear to push the repitition rate higher than 'usual' :-) ?
Sounds like a good design.  Yes, in general you should be fine at high repetition rate since you have kept duty cycle constant.  However, two possible high-repetition-rate issues come to mind:
1) The anti-parallel diode in FGH60N60SMD has half the current rating and just under 1/4th the power dissipation capability of the IGBT.  Primary current ring-down after enable ends is conducted through diodes.  Thus diode current duty cycle does increase with repetition rate.  The initial failure may have been with a diode, which then fried the opposite IGBT and then the IGBT with the failed diode.  You may be able to determine if diodes are good or not by dissecting parts.
2) Depending on GDT+wiring leakage inductance, sometimes there are Vge rings or other anomalies at the end of bursts.  Resulting IGBT stress may be tolerated at low BPS, but generate too much total heat at high BPS.

Good luck with your repairs.
David Knierim

Offline Hydron

  • Administrator
  • High Voltage Engineer
  • *****
  • Posts: 446
  • Karma: +19/-0
    • View Profile
Re: Bridge failure - which went first, board or IGBT?
« Reply #5 on: September 04, 2022, 08:33:46 PM »
1) The anti-parallel diode in FGH60N60SMD has half the current rating and just under 1/4th the power dissipation capability of the IGBT.  Primary current ring-down after enable ends is conducted through diodes.  Thus diode current duty cycle does increase with repetition rate.  The initial failure may have been with a diode, which then fried the opposite IGBT and then the IGBT with the failed diode.  You may be able to determine if diodes are good or not by dissecting parts.
This is one of the reasons I picked up some FGY75N60SMD - the diode is still rated less than the IGBT, but by a smaller margin. This is potentially important not just with high BPS, but if free-wheeling or a phase shifted QCW bridge is used - in both these use cases the diode gets a decent workout.

Offline GrantV

  • High Voltage Experimenter
  • **
  • Posts: 70
  • Karma: +3/-0
    • View Profile
Re: Bridge failure - which went first, board or IGBT?
« Reply #6 on: September 05, 2022, 02:39:00 PM »
Sounds like a good design.  Yes, in general you should be fine at high repetition rate since you have kept duty cycle constant.  However, two possible high-repetition-rate issues come to mind:
1) The anti-parallel diode in FGH60N60SMD has half the current rating and just under 1/4th the power dissipation capability of the IGBT.  Primary current ring-down after enable ends is conducted through diodes.  Thus diode current duty cycle does increase with repetition rate.  The initial failure may have been with a diode, which then fried the opposite IGBT and then the IGBT with the failed diode.  You may be able to determine if diodes are good or not by dissecting parts.
2) Depending on GDT+wiring leakage inductance, sometimes there are Vge rings or other anomalies at the end of bursts.  Resulting IGBT stress may be tolerated at low BPS, but generate too much total heat at high BPS.

Good luck with your repairs.

Hey Dave, LOL thank you, I am quite proud of my interrupter :-)

You see, this is exactly why I love this forum so much, post what initially sounds like a no brainer question and all of a sudden you find yourself learning about things you would never have thought of before  ;D Certainly true in my case as I would not have given the anti-parallel diode a seconds thought! I'll have to go do more homework! Happy days.

Re the repairs ... nope, I'll be scrapping that board thank you! Apart from that I do have spares of that board, I'm using the opportunity as an excuse to put my dual bridge board to the test :-) pics later

High Voltage Forum

Re: Bridge failure - which went first, board or IGBT?
« Reply #6 on: September 05, 2022, 02:39:00 PM »

 


* Recent Topics and Posts

post Re: Recommended development boards for QCWDRSSTC
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
davekni
Today at 07:33:57 PM
post Re: Ud failure
[Dual Resonant Solid State Tesla coils (DRSSTC)]
FonziDaytona
Today at 07:06:33 PM
post What am I missing?!?!?
[Spark Gap Tesla Coils (SGTC)]
Conrad73
Today at 06:35:43 PM
post Radiometer Copenhagen OSG 42b Oscilloscope Repair, From The 1950'ish
[Laboratories, Equipment and Tools]
Mads Barnkob
Today at 03:18:22 PM
post Re: Recommended development boards for QCWDRSSTC
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
Rafft
Today at 02:53:30 PM
post Recommended development boards for QCWDRSSTC
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
dru
Today at 09:05:37 AM
post Re: Ud failure
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Mads Barnkob
Today at 08:29:09 AM
post Re: Ud failure
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
Today at 05:27:41 AM
post Re: Gauss meter for strong magnetic fields
[Laboratories, Equipment and Tools]
klugesmith
Today at 02:12:21 AM
post Ud failure
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
Today at 01:50:45 AM
post Re: controlling the negative gate bias voltage of the Gate drive transformer
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 24, 2022, 09:36:58 PM
post UD2.x mod
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Rafft
September 24, 2022, 05:06:28 PM
post Re: Gate drive transformer with negative gate bias voltage
[Dual Resonant Solid State Tesla coils (DRSSTC)]
prabhatkumar
September 24, 2022, 06:56:35 AM
post Re: Gate drive transformer with negative gate bias voltage
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 24, 2022, 06:09:03 AM
post Re: Gauss meter for strong magnetic fields
[Laboratories, Equipment and Tools]
davekni
September 24, 2022, 01:32:08 AM
post Re: Some questions about my first drsstc.
[Dual Resonant Solid State Tesla coils (DRSSTC)]
mthome4
September 23, 2022, 10:55:21 PM
post Re: Gauss meter for strong magnetic fields
[Laboratories, Equipment and Tools]
AstRii
September 23, 2022, 10:39:13 PM
post controlling the negative gate bias voltage of the Gate drive transformer
[Dual Resonant Solid State Tesla coils (DRSSTC)]
prabhatkumar
September 23, 2022, 05:48:17 PM
post Gauss meter for strong magnetic fields
[Laboratories, Equipment and Tools]
Peregrine
September 23, 2022, 02:01:10 PM
post Re: UD2.7 dual Purpose Use
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 23, 2022, 03:04:31 AM
post Re: UD2.7 dual Purpose Use
[Dual Resonant Solid State Tesla coils (DRSSTC)]
FonziDaytona
September 22, 2022, 04:15:36 PM
post Re: SSTC - PCB design
[Beginners]
Przemekk00
September 22, 2022, 12:39:51 PM
post Re: Possible Leads on Single Photon Camera
[General Chat]
alan sailer
September 22, 2022, 12:05:55 AM
post Re: Possible Leads on Single Photon Camera
[General Chat]
Mads Barnkob
September 21, 2022, 10:32:29 PM
post Possible Leads on Single Photon Camera
[General Chat]
alan sailer
September 21, 2022, 03:57:38 PM
post Re: Driverless Single Mosfet Relay interrupted SSTC? - [All kinds of problems]
[Solid State Tesla Coils (SSTC)]
davekni
September 21, 2022, 05:50:15 AM
post Re: Musical interrupter problems
[Solid State Tesla Coils (SSTC)]
RoamingD
September 20, 2022, 10:29:41 PM
post Re: Musical interrupter problems
[Solid State Tesla Coils (SSTC)]
Mads Barnkob
September 20, 2022, 08:24:30 PM
post Re: Driverless Single Mosfet Relay interrupted SSTC? - [All kinds of problems]
[Solid State Tesla Coils (SSTC)]
TiagoBS
September 20, 2022, 06:23:54 PM
post Re: Some questions about my first drsstc.
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 20, 2022, 05:20:07 AM
post Re: TO247 mounting
[Beginners]
davekni
September 20, 2022, 05:15:35 AM
post Re: MidiStick V2.0: Next gen tesla coil interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
TMaxElectronics
September 19, 2022, 11:43:47 PM
post Re: TO247 mounting
[Beginners]
Weston
September 19, 2022, 09:58:56 PM
post Re: Some questions about my first drsstc.
[Dual Resonant Solid State Tesla coils (DRSSTC)]
mthome4
September 19, 2022, 09:05:35 PM
post Re: Musical interrupter problems
[Solid State Tesla Coils (SSTC)]
RoamingD
September 19, 2022, 12:58:35 PM
post Re: UD2.7 dual Purpose Use
[Dual Resonant Solid State Tesla coils (DRSSTC)]
FonziDaytona
September 19, 2022, 12:13:46 AM
post Re: MMC capacitor crash
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 19, 2022, 12:09:22 AM
post Re: UD2.7 dual Purpose Use
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 18, 2022, 11:38:51 PM
post Re: UD2.7 dual Purpose Use
[Dual Resonant Solid State Tesla coils (DRSSTC)]
FonziDaytona
September 18, 2022, 10:41:54 PM
post Re: Musical interrupter problems
[Solid State Tesla Coils (SSTC)]
davekni
September 18, 2022, 10:31:32 PM
post Re: Musical interrupter problems
[Solid State Tesla Coils (SSTC)]
RoamingD
September 18, 2022, 10:09:33 PM
post Re: UD2.7 dual Purpose Use
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 18, 2022, 09:58:34 PM
post Re: UD2.7 dual Purpose Use
[Dual Resonant Solid State Tesla coils (DRSSTC)]
FonziDaytona
September 18, 2022, 08:45:21 PM
post Re: Musical interrupter problems
[Solid State Tesla Coils (SSTC)]
Mads Barnkob
September 18, 2022, 07:55:11 PM
post Re: Syntherrupter - A Feature-rich, Polyphonic Interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
Max
September 18, 2022, 07:25:30 PM
post TO247 mounting
[Beginners]
mthome4
September 18, 2022, 06:32:10 PM
post Musical interrupter problems
[Solid State Tesla Coils (SSTC)]
RoamingD
September 18, 2022, 05:48:17 PM
post Re: UD2.7 dual Purpose Use
[Dual Resonant Solid State Tesla coils (DRSSTC)]
FonziDaytona
September 18, 2022, 05:44:14 PM
post Re: MMC capacitor crash
[Dual Resonant Solid State Tesla coils (DRSSTC)]
JCF
September 18, 2022, 05:22:31 PM
post Re: UD2.7 dual Purpose Use
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 18, 2022, 06:10:33 AM
post Re: UD2.7 dual Purpose Use
[Dual Resonant Solid State Tesla coils (DRSSTC)]
FonziDaytona
September 18, 2022, 12:47:41 AM
post Re: Some questions about my first drsstc.
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 17, 2022, 06:37:23 PM
post Re: Some questions about my first drsstc.
[Dual Resonant Solid State Tesla coils (DRSSTC)]
mthome4
September 17, 2022, 11:56:26 AM
post Re: Some questions about my first drsstc.
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 17, 2022, 01:50:27 AM
post Re: Some questions about my first drsstc.
[Dual Resonant Solid State Tesla coils (DRSSTC)]
mthome4
September 16, 2022, 11:05:46 PM
post Re: MMC capacitor crash
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Mads Barnkob
September 16, 2022, 09:48:56 PM
post Re: MMC capacitor crash
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 16, 2022, 09:04:59 PM
post Re: MMC capacitor crash
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Mads Barnkob
September 16, 2022, 08:32:01 PM
post Re: MMC capacitor crash
[Dual Resonant Solid State Tesla coils (DRSSTC)]
JCF
September 16, 2022, 04:17:31 PM
post Re: MMC capacitor crash
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 16, 2022, 05:40:05 AM
post Re: Getting last joules out of batteries
[Laboratories, Equipment and Tools]
klugesmith
September 15, 2022, 11:18:56 PM
post Re: SALE(US) - 30 amp 3 phase GE volt-pac variac auto transformer 0-520v
[Sell / Buy / Trade]
rikkitikkitavi
September 15, 2022, 10:16:03 PM
post Re: MMC capacitor crash
[Dual Resonant Solid State Tesla coils (DRSSTC)]
JCF
September 15, 2022, 04:15:12 PM
post Re: MMC capacitor crash
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 15, 2022, 05:54:55 AM
post Re: Getting last joules out of batteries
[Laboratories, Equipment and Tools]
Weston
September 14, 2022, 10:36:37 PM
post Re: Help with PLL induction heater driver
[Electronic Circuits]
dbach
September 14, 2022, 09:09:09 PM
post Re: Few questions before a TC show
[Dual Resonant Solid State Tesla coils (DRSSTC)]
AstRii
September 14, 2022, 06:47:04 PM
post Re: The most powerful Russian Tesla coil in Europe (and maybe in the world)
[Dual Resonant Solid State Tesla coils (DRSSTC)]
hammertone
September 14, 2022, 04:45:43 PM
post Re: MMC capacitor crash
[Dual Resonant Solid State Tesla coils (DRSSTC)]
JCF
September 14, 2022, 03:43:03 PM
post Re: SSTC - PCB design
[Beginners]
davekni
September 14, 2022, 06:38:17 AM
post Re: Sources for optical parts?
[Light, Lasers and Optics]
klugesmith
September 14, 2022, 02:16:33 AM
post Re: Circuit drawing software for dummies
[Printed Circuit Board]
Twospoons
September 14, 2022, 12:31:44 AM
post Re: Sources for optical parts?
[Light, Lasers and Optics]
Twospoons
September 13, 2022, 10:21:13 PM
post Re: The most powerful Russian Tesla coil in Europe (and maybe in the world)
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Mads Barnkob
September 13, 2022, 10:20:28 PM
post Re: Where to find a "small" focal spot x-ray tube
[X-ray]
Fijcho
September 13, 2022, 10:05:48 PM
post Re: MMC capacitor crash
[Dual Resonant Solid State Tesla coils (DRSSTC)]
JCF
September 13, 2022, 06:00:00 PM
post Re: Sources for optical parts?
[Light, Lasers and Optics]
klugesmith
September 13, 2022, 05:37:54 PM
post Re: Few questions before a TC show
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Mads Barnkob
September 13, 2022, 10:23:49 AM
post Re: The most powerful Russian Tesla coil in Europe (and maybe in the world)
[Dual Resonant Solid State Tesla coils (DRSSTC)]
TeslaFX_rus
September 13, 2022, 09:59:45 AM
post Sources for optical parts?
[Light, Lasers and Optics]
Twospoons
September 13, 2022, 07:36:43 AM
post Re: Some questions about my first drsstc.
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 13, 2022, 03:43:58 AM
post Re: Circuit drawing software for dummies
[Printed Circuit Board]
LoOdaK
September 12, 2022, 09:45:41 PM
post Re: Some questions about my first drsstc.
[Dual Resonant Solid State Tesla coils (DRSSTC)]
mthome4
September 12, 2022, 08:09:42 PM
post Re: Circuit drawing software for dummies
[Printed Circuit Board]
Mads Barnkob
September 12, 2022, 04:34:54 PM
post Re: Some questions about my first drsstc.
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Maju
September 12, 2022, 04:32:03 PM
post Re: SSTC - PCB design
[Beginners]
Przemekk00
September 12, 2022, 03:00:32 PM
post Re: Circuit drawing software for dummies
[Printed Circuit Board]
LoOdaK
September 12, 2022, 02:26:47 PM
post Re: Circuit drawing software for dummies
[Printed Circuit Board]
Mads Barnkob
September 12, 2022, 01:09:53 PM
post Few questions before a TC show
[Dual Resonant Solid State Tesla coils (DRSSTC)]
AstRii
September 12, 2022, 12:52:58 PM
post Re: Circuit drawing software for dummies
[Printed Circuit Board]
Twospoons
September 12, 2022, 07:20:11 AM
post Re: Help with PLL induction heater driver
[Electronic Circuits]
petespaco
September 12, 2022, 04:48:21 AM
post Circuit drawing software for dummies
[Printed Circuit Board]
abstruse1
September 12, 2022, 03:33:52 AM
post Help with PLL induction heater driver
[Electronic Circuits]
dbach
September 12, 2022, 02:28:17 AM
post Re: QCW music with Midi
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyglas
September 11, 2022, 11:32:31 PM
post SALE(US) - 30 amp 3 phase GE volt-pac variac auto transformer 0-520v
[Sell / Buy / Trade]
pache11
September 11, 2022, 10:31:06 PM
post Re: Question about Flip-Flop wiring for DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
bockett
September 11, 2022, 10:28:43 PM
post Re: Question about Flip-Flop wiring for DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 11, 2022, 10:15:59 PM
post Re: UV-cured cyanoacrylate glues?
[Light, Lasers and Optics]
pache11
September 11, 2022, 10:05:44 PM
post Re: CO2 laser refurbishing
[Light, Lasers and Optics]
pache11
September 11, 2022, 09:57:35 PM
post Re: Question about Flip-Flop wiring for DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
bockett
September 11, 2022, 09:24:04 PM

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