Author Topic: Alternative phase lead  (Read 237 times)

Offline panjaksli

  • High Voltage Enthusiast
  • *
  • Posts: 11
  • Karma: +0/-0
    • View Profile
Alternative phase lead
« on: January 26, 2021, 10:24:39 AM »
Hey everyone,

So I have been looking for a proper analog phase-lead circuit, but unfortunately there is not much information out there.
One thing that's commonly used is variable inductor around 10s of uH with a 51 Ohm resistor, and the feedback voltage being measured across only the inductor. Correct ?
For whatever reason, I couldn't get the feedback to work, even with 1:100, 1:500, 1:1000 CTs. Seems like board wouldn't pick up the weak signal (Clouded leopard driver from Ali).

However the reason I'm writing this post, is that I found quite well working alternative. And that is, to use much larger value inductor 100uH - 300uH straight at the output of CT without any resistor. This way I was able to get the desired phase-lead without signal attenuation. But the thing is, it is pretty hard/impossible to find variable inductor of that value.
And by using a ferrite core, it's pretty hard to hit the sweetspot, because one turn could make the difference between having stable feedback and none feedback. Eg. (200-260uH for me)
But lucky me, the 10 piece package of "same" ferrite cores from Ali had anything but the same cores. After some digging I was able to find a core that would have 230uH at 20 or so turns, so the lower "AL" value is better for fine tuning.

Anyways, here is a picture, I have only one small issue, the igbts seem to turn on sligthly before zero crossing, but it doesn't seem to affect anything, since the feedback works perfectly.


Offline davekni

  • High Voltage Senior
  • *****
  • Posts: 993
  • Karma: +44/-0
  • Physicist, engineer (electronic), and hobbiest
    • View Profile
Re: Alternative phase lead
« Reply #1 on: January 26, 2021, 07:12:46 PM »
The normal UD2.7 etc. feedback signal is CT output current across both the 51-ohm resistor and the variable inductor, not just the inductor.

Without the circuit for your driver, there's no way to know what phase lead options exist.  There may be clamp diodes directly across the CT input terminals.  That makes input impedance vary as current changes.  Your phase-lead solution may change phase as primary current changes.

Voltage switching slightly before current zero-crossing is ideal, better than at the exact same time.  That way the residual current causes a gentle voltage transition during the dead-time when all IGBTs are off.
David Knierim

Offline panjaksli

  • High Voltage Enthusiast
  • *
  • Posts: 11
  • Karma: +0/-0
    • View Profile
Re: Alternative phase lead
« Reply #2 on: February 13, 2021, 11:34:09 PM »
Well, none configuration of R + L worked, but whatever, if the inductor alone works too, don't change it.
I found schematics of the input filter from the clouded leopard driver, it has infact a network of zener/schottky clamping diodes on the input, and then tesistor to the fpga, however adding resistor in series with feedback to reduce load on the CT doesn't really help, I may try lowering the CT ratio even further.

Also found out that the board itself has about 300ns+ propagation delay, which certainly doesn't help.

High Voltage Forum

Re: Alternative phase lead
« Reply #2 on: February 13, 2021, 11:34:09 PM »

 


* Recent Topics and Posts

post Re: Voltage readings on 13.8KV
[Voltage Multipliers]
Mads Barnkob
March 07, 2021, 08:57:23 PM
post Re: MOT tesla coil: Why put the midpoint to ground ?
[Spark Gap Tesla Coils (SGTC)]
Mads Barnkob
March 07, 2021, 08:53:07 PM
post Re: Identification of capacitors
[General Chat]
Mr_Project
March 07, 2021, 08:26:27 PM
post MOT tesla coil: Why put the midpoint to ground ?
[Spark Gap Tesla Coils (SGTC)]
paulj
March 07, 2021, 05:49:49 PM
post Voltage readings on 13.8KV
[Voltage Multipliers]
lex1969
March 07, 2021, 10:47:55 AM
post Re: Etching PCBs with a SLA 3d printer
[Printed Circuit Board]
klugesmith
March 07, 2021, 02:48:08 AM
post Re: Question about the meaning of "±20V" specification for Vge on IGBT datasheet
[Solid State Tesla Coils (SSTC)]
davekni
March 07, 2021, 02:19:47 AM
post Re: Etching PCBs with a SLA 3d printer
[Printed Circuit Board]
TMaxElectronics
March 07, 2021, 01:49:55 AM
post Re: Etching PCBs with a SLA 3d printer
[Printed Circuit Board]
klugesmith
March 07, 2021, 01:26:52 AM
post Re: Question about the meaning of "±20V" specification for Vge on IGBT datasheet
[Solid State Tesla Coils (SSTC)]
jhorneljohn02
March 07, 2021, 12:30:36 AM
post Re: Coil destroyed at 4ms on-time.
[Dual Resonant Solid State Tesla coils (DRSSTC)]
fh89
March 06, 2021, 11:30:27 PM
post Re: Simplified mutli-stage coilgun idea
[Induction Launchers, Coil Guns and Rails guns]
johnnyzoo
March 06, 2021, 10:13:19 PM
post Re: Coil destroyed at 4ms on-time.
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
March 06, 2021, 09:54:31 PM
post Re: Coil destroyed at 4ms on-time.
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Mads Barnkob
March 06, 2021, 09:48:37 PM
post Re: Etching PCBs with a SLA 3d printer
[Printed Circuit Board]
TMaxElectronics
March 06, 2021, 09:44:20 PM
post Re: Identification of capacitors
[General Chat]
Mads Barnkob
March 06, 2021, 09:33:17 PM
post Re: Coil destroyed at 4ms on-time.
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Hydron
March 06, 2021, 09:21:44 PM
post Re: Coil destroyed at 4ms on-time.
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
March 06, 2021, 09:15:09 PM
post Re: Osciloscope
[Laboratories, Equipment and Tools]
rikkitikkitavi
March 06, 2021, 08:55:52 PM
post Re: Coil destroyed at 4ms on-time.
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Hydron
March 06, 2021, 08:51:06 PM
post Re: Help for people buying the "12-48 Volt 1800/2500 Watt ZVS induction Heater"
[Electronic Circuits]
rikkitikkitavi
March 06, 2021, 08:48:52 PM
post Re: Etching PCBs with a SLA 3d printer
[Printed Circuit Board]
Twospoons
March 06, 2021, 08:44:23 PM
post Re: Question about the meaning of "±20V" specification for Vge on IGBT datasheet
[Solid State Tesla Coils (SSTC)]
davekni
March 06, 2021, 06:26:56 PM
post Re: Coil destroyed at 4ms on-time.
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
March 06, 2021, 06:24:15 PM
post Question about the meaning of "±20V" specification for Vge on IGBT datasheet
[Solid State Tesla Coils (SSTC)]
jhorneljohn02
March 06, 2021, 06:00:21 PM
post Re: Welcome new members, come say hello and tell a little about yourself :)
[General Chat]
jhorneljohn02
March 06, 2021, 05:53:40 PM
post Re: Aliexpress Yunbao pulse skipping Product Guide manual
[Dual Resonant Solid State Tesla coils (DRSSTC)]
GrantV
March 06, 2021, 05:49:48 PM
post Re: Search for opinions concerning the use or test of a yunbao / Ebay drsstc skp
[Dual Resonant Solid State Tesla coils (DRSSTC)]
JCF
March 06, 2021, 05:31:42 PM
post Re: Baxandall converter strange output
[Transformer (Ferrite Core)]
dreamth
March 06, 2021, 05:16:24 PM
post Re: Aliexpress Yunbao pulse skipping Product Guide manual
[Dual Resonant Solid State Tesla coils (DRSSTC)]
JCF
March 06, 2021, 04:35:37 PM
post Identification of capacitors
[General Chat]
Mr_Project
March 06, 2021, 03:43:41 PM
post Re: Etching PCBs with a SLA 3d printer
[Printed Circuit Board]
TMaxElectronics
March 06, 2021, 12:33:22 PM
post Re: Coil destroyed at 4ms on-time.
[Dual Resonant Solid State Tesla coils (DRSSTC)]
fh89
March 06, 2021, 08:27:54 AM
post Re: Coil destroyed at 4ms on-time.
[Dual Resonant Solid State Tesla coils (DRSSTC)]
alexhanyuan
March 06, 2021, 06:49:27 AM
post Re: Coil destroyed at 4ms on-time.
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
March 06, 2021, 06:33:58 AM
post Re: Rocket engine questions
[General Chat]
plasma
March 06, 2021, 06:20:59 AM
post Re: Rocket engine questions
[General Chat]
klugesmith
March 06, 2021, 06:03:40 AM
post Re: Help for people buying the "12-48 Volt 1800/2500 Watt ZVS induction Heater"
[Electronic Circuits]
davekni
March 06, 2021, 05:59:49 AM
post Re: Large coil experimenting with long on-times.
[Dual Resonant Solid State Tesla coils (DRSSTC)]
fh89
March 06, 2021, 05:08:48 AM
post Re: Rocket engine questions
[General Chat]
Twospoons
March 06, 2021, 04:50:01 AM
post Re: Rocket engine questions
[General Chat]
klugesmith
March 06, 2021, 04:24:44 AM
post Re: Help for people buying the "12-48 Volt 1800/2500 Watt ZVS induction Heater"
[Electronic Circuits]
hightemp1
March 06, 2021, 03:41:03 AM
post Re: Etching PCBs with a SLA 3d printer
[Printed Circuit Board]
Twospoons
March 06, 2021, 01:20:13 AM
post Re: Etching PCBs with a SLA 3d printer
[Printed Circuit Board]
TMaxElectronics
March 05, 2021, 11:26:36 PM
post Re: Rocket engine questions
[General Chat]
plasma
March 05, 2021, 10:17:39 PM
post Re: Help for people buying the "12-48 Volt 1800/2500 Watt ZVS induction Heater"
[Electronic Circuits]
rikkitikkitavi
March 05, 2021, 08:48:19 PM
post Re: Help for people buying the "12-48 Volt 1800/2500 Watt ZVS induction Heater"
[Electronic Circuits]
davekni
March 05, 2021, 07:41:34 PM
post Re: Baxandall converter strange output
[Transformer (Ferrite Core)]
dreamth
March 05, 2021, 07:22:17 PM
post Re: Baxandall converter strange output
[Transformer (Ferrite Core)]
dreamth
March 05, 2021, 07:18:02 PM
post Re: Baxandall converter strange output
[Transformer (Ferrite Core)]
davekni
March 05, 2021, 07:12:26 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