Author Topic: Small DIY plasma globe using ZVS oscillator  (Read 972 times)

Online davekni

  • High Voltage Senior
  • *****
  • Posts: 555
  • Karma: +30/-0
  • Physicist, engineer (electronic), and hobbiest
    • View Profile
Small DIY plasma globe using ZVS oscillator
« on: January 22, 2020, 06:21:31 AM »
This is my latest little project - only 20 watts.  Made a plasma ball from a plastic wine glass filled with about 15kPa of argon.  Works some with air at lower pressure, around 5kPa.  Experimented with argon/helium mixtures, but plain argon was the brightest.  Don't have neon nor xenon around (due to expense), the normal gasses inside plasma balls.  Mine isn't as bright and doesn't have multiple colors.  Still fun.



For the HV transformer, I used a pair of small already-potted transformers from EBay:
https://www.ebay.com/itm/20KV-high-frequency-high-voltage-transformer-ignition-coil-inverter-driver-bNWUS/323974762353?hash=item4b6e668f71:m:mg4RAb8mo-3R0Me2JUcxcfw

The pair are electrically and magnetically in series, both primary and secondary.  Magnetic path is closed with some NiZn ferrite pieces (low electrical conductivity type).  Still some gap due to the potting.  Driving circuit consists of a normal hard-switched buck converter using the same inductor as the ZVS input inductor, 19V to 15V(adjustable), with ~1.2A current limit.  Separate buck and ZVS boards, still connected with clip leads in the pictures:





The HV winding capacitance and load (plasma ball) capacitance alone makes a ~25kHz resonant frequency.  So, I added only a little bit more primary-side capacitance.  This creates an issue with the two possible resonant modes, one at ~25kHz and another (with primary and secondary voltages opposite) at ~530kHz.  To keep the ZVS oscillation from locking to 530kHz, I added a series LRC notch filter across the ZVS output (transformer primary).  Schematic is:


Here are a few waveforms of the ZVS outputs (transformer primary terminals).  First is with low load (nothing touching the plasma ball).  Second and third are with load (hand on plasma ball), showing lower voltage (due to buck-converter current limit) and a cycle or two of high-frequency mode ring at each zero-crossing.  Without the notch filter, the ZVS locks to the high frequency and stays there.




Any suggestions for improvements?

2/2020 update:  After a longer run, the little transformers developed an arc path between the two, burning through the potting material.  I've replaced them with two identical parts glued end-to-end instead, avoiding the series HV being adjacent.  Haven't ran that configuration for long yet.
« Last Edit: February 20, 2020, 05:17:40 AM by davekni »
David Knierim

Offline John123

  • High Voltage Technician
  • ***
  • Posts: 155
  • Karma: +2/-0
  • All the gear, no idea. UK
    • View Profile
Re: Small DIY plasma globe using ZVS oscillator
« Reply #1 on: April 07, 2020, 02:29:21 AM »
Very cool! Wish I could help with your question for suggestions but I'm not at that level of skill yet, maybe some ferrite beads could help with the spiking on the primary waveforms?

Aw I hate it when hv transformers have insulation breakdown during the fun.

Offline ritaismyconscience

  • High Voltage Technician
  • ***
  • Posts: 159
  • Karma: +3/-0
    • View Profile
Re: Small DIY plasma globe using ZVS oscillator
« Reply #2 on: July 19, 2020, 03:45:01 AM »
I bought the same ferrite transformers a while ago. Since the transformer needed a pulse of around 100Vpp to form the arc in flyback mode, I needed to step up the output of the ZVS using another transformer.

I got a power supply ferrite core and made a 5+5:60 transformer. I used the ZVS circuit but with 30V 60A mosfets and 24V zeners for protection. When I powered the ZVS with 5V, I got around 60Vpp at the output of the transformer, so not as good as the flyback circuit. This was then fed into two transformers connected in series (I think they're rated for DC, not AC)

Here's the result, circuit uses 40W at 5V.


I can stretch the arc over an inch.

High Voltage Forum

Re: Small DIY plasma globe using ZVS oscillator
« Reply #2 on: July 19, 2020, 03:45:01 AM »

 


* Recent Topics and Posts

post Re: Rogowski current probe
[Laboratories, Equipment and Tools]
Hydron
September 27, 2020, 11:48:35 PM
post Polyphonic Interrupter with STM32F103C8T6 (Bluepill)
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
Zipdox
September 27, 2020, 11:43:14 PM
post Re: Rogowski current probe
[Laboratories, Equipment and Tools]
flyglas
September 27, 2020, 11:01:13 PM
post type of driver
[Dual Resonant Solid State Tesla coils (DRSSTC)]
octopus1
September 27, 2020, 10:51:03 PM
post Re: Easy to build Polyphonic MIDI Interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
Max
September 27, 2020, 10:44:43 PM
post Re: MIDI videos from my DRSSTC1/2/3 demonstrations/shows
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Mads Barnkob
September 27, 2020, 09:44:58 PM
post Re: DRSSTC Tuning for Music vs Big Sparks?
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 27, 2020, 09:20:32 PM
post Re: Easy to build Polyphonic MIDI Interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
futurist
September 27, 2020, 07:49:49 PM
post Stroboscopic photography & motors
[Digital Compact Camera]
klugesmith
September 27, 2020, 07:08:06 PM
post Re: Led Closeups with Mobile phone and lens .
[Smart Phones]
klugesmith
September 27, 2020, 06:43:46 PM
post Re: DRSSTC Tuning for Music vs Big Sparks?
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Mads Barnkob
September 27, 2020, 06:42:46 PM
post Re: Finding accelerometer location inside a phone
[Smart Phones]
klugesmith
September 27, 2020, 06:36:41 PM
post Re: steam engine
[Capacitor Banks]
plasma
September 27, 2020, 02:32:14 PM
post Re: Easy to build Polyphonic MIDI Interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
Max
September 27, 2020, 02:02:53 PM
post Re: Easy to build Polyphonic MIDI Interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
futurist
September 27, 2020, 12:24:20 PM
post Re: Easy to build Polyphonic MIDI Interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
Max
September 27, 2020, 12:52:36 AM
post Re: DRSSTC Tuning for Music vs Big Sparks?
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 26, 2020, 11:06:04 PM
post Re: One NOS ac flyback is nice. Finding its identical twin 3 months later is awesome
[Transformer (Ferrite Core)]
profdc9
September 26, 2020, 10:48:41 PM
post Re: Rogowski current probe
[Laboratories, Equipment and Tools]
Hydron
September 26, 2020, 05:27:37 PM
post Re: DRSSTC Tuning for Music vs Big Sparks?
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Zipdox
September 26, 2020, 04:32:53 PM
post Re: DRSSTC Tuning for Music vs Big Sparks?
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Mads Barnkob
September 26, 2020, 04:17:51 PM
post Re: DRSSTC Tuning for Music vs Big Sparks?
[Dual Resonant Solid State Tesla coils (DRSSTC)]
GKnapp
September 26, 2020, 02:06:04 PM
post Re: Rogowski current probe
[Laboratories, Equipment and Tools]
flyglas
September 26, 2020, 10:57:58 AM
post Re: DRSSTC Tuning for Music vs Big Sparks?
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Mads Barnkob
September 26, 2020, 08:55:27 AM
post Re: DRSSTC Tuning for Music vs Big Sparks?
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 26, 2020, 05:19:45 AM
post Re: Rogowski current probe
[Laboratories, Equipment and Tools]
klugesmith
September 26, 2020, 04:46:12 AM
post Re: Easy to build Polyphonic MIDI Interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
Max
September 26, 2020, 01:14:47 AM
post Re: Rogowski current probe
[Laboratories, Equipment and Tools]
flyglas
September 25, 2020, 09:41:10 PM
post Re: DRSSTC Tuning for Music vs Big Sparks?
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Mads Barnkob
September 25, 2020, 08:40:39 PM
post Re: Easy to build Polyphonic MIDI Interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
Mads Barnkob
September 25, 2020, 08:26:52 PM
post Re: FPGA speeds these days?
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
SteveN87
September 25, 2020, 06:56:41 PM
post Re: FPGA speeds these days?
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
klugesmith
September 25, 2020, 06:15:47 PM
post Re: FPGA speeds these days?
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
SteveN87
September 25, 2020, 01:56:27 PM
post Re: FPGA speeds these days?
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
TMaxElectronics
September 25, 2020, 11:55:05 AM
post Re: FPGA speeds these days?
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
Weston
September 25, 2020, 09:18:51 AM
post One NOS ac flyback is nice. Finding its identical twin 3 months later is awesome
[Transformer (Ferrite Core)]
extremeodd
September 25, 2020, 03:43:26 AM
post Re: FPGA speeds these days?
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
davekni
September 25, 2020, 03:42:56 AM
post FPGA speeds these days?
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
klugesmith
September 25, 2020, 02:13:40 AM
post Re: Server PSU OPV Hack - Fujitsu DPS-800GB-5 A
[Electronic Circuits]
klugesmith
September 24, 2020, 03:02:00 PM
post Re: Server PSU OPV Hack - Fujitsu DPS-800GB-5 A
[Electronic Circuits]
v.coelho
September 24, 2020, 01:11:27 PM
post Re: Info needed: probably old military High Voltage Multiplier?
[Voltage Multipliers]
Zipdox
September 24, 2020, 10:25:42 AM
post Re: Info needed: probably old military High Voltage Multiplier?
[Voltage Multipliers]
johnnyzoo
September 24, 2020, 07:32:43 AM
post Re: Current transformer for narrow spaces
[Laboratories, Equipment and Tools]
klugesmith
September 23, 2020, 11:20:53 PM
post WTS [US]:"Terry filter" varistors for sale
[Sell / Buy / Trade]
MRMILSTAR
September 23, 2020, 10:41:54 PM
post Re: Info needed: probably old military High Voltage Multiplier?
[Voltage Multipliers]
Zipdox
September 23, 2020, 10:25:07 PM
post Info needed: probably old military High Voltage Multiplier?
[Voltage Multipliers]
HighVoltageRulezz
September 23, 2020, 10:06:30 PM
post Re: Server PSU OPV Hack - Fujitsu DPS-800GB-5 A
[Electronic Circuits]
petespaco
September 23, 2020, 04:26:34 PM
post Re: 6" Coil Update now 72" and better lighting
[Spark Gap Tesla Coils (SGTC)]
klugesmith
September 23, 2020, 03:06:28 PM
post Re: Server PSU OPV Hack - Fujitsu DPS-800GB-5 A
[Electronic Circuits]
Zipdox
September 23, 2020, 01:34:42 PM
post Server PSU OPV Hack - Fujitsu DPS-800GB-5 A
[Electronic Circuits]
v.coelho
September 23, 2020, 01:11:50 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