If you need assistance, please send an email to forum at 4hv dot org. To ensure your email is not marked as spam, please include the phrase "4hv help" in the subject line. You can also find assistance via IRC, at irc.shadowworld.net, room #hvcomm.
Support 4hv.org!
Donate:
4hv.org is hosted on a dedicated server. Unfortunately, this server costs and we rely on the help of site members to keep 4hv.org running. Please consider donating. We will place your name on the thanks list and you'll be helping to keep 4hv.org alive and free for everyone. Members whose names appear in red bold have donated recently. Green bold denotes those who have recently donated to keep the server carbon neutral.
Special Thanks To:
Aaron Holmes
Aaron Wheeler
Adam Horden
Alan Scrimgeour
Andre
Andrew Haynes
Anonymous000
asabase
Austin Weil
barney
Barry
Bert Hickman
Bill Kukowski
Blitzorn
Brandon Paradelas
Bruce Bowling
BubeeMike
Byong Park
Cesiumsponge
Chris F.
Chris Hooper
Corey Worthington
Derek Woodroffe
Dalus
Dan Strother
Daniel Davis
Daniel Uhrenholt
datasheetarchive
Dave Billington
Dave Marshall
David F.
Dennis Rogers
drelectrix
Dr. John Gudenas
Dr. Spark
E.TexasTesla
eastvoltresearch
Eirik Taylor
Erik Dyakov
Erlend^SE
Finn Hammer
Firebug24k
GalliumMan
Gary Peterson
George Slade
GhostNull
Gordon Mcknight
Graham Armitage
Grant
GreySoul
Henry H
IamSmooth
In memory of Leo Powning
Jacob Cash
James Howells
James Pawson
Jeff Greenfield
Jeff Thomas
Jesse Frost
Jim Mitchell
jlr134
Joe Mastroianni
John Forcina
John Oberg
John Willcutt
Jon Newcomb
klugesmith
Leslie Wright
Lutz Hoffman
Mads Barnkob
Martin King
Mats Karlsson
Matt Gibson
Matthew Guidry
mbd
Michael D'Angelo
Mikkel
mileswaldron
mister_rf
Neil Foster
Nick de Smith
Nick Soroka
nicklenorp
Nik
Norman Stanley
Patrick Coleman
Paul Brodie
Paul Jordan
Paul Montgomery
Ped
Peter Krogen
Peter Terren
PhilGood
Richard Feldman
Robert Bush
Royce Bailey
Scott Fusare
Scott Newman
smiffy
Stella
Steven Busic
Steve Conner
Steve Jones
Steve Ward
Sulaiman
Thomas Coyle
Thomas A. Wallace
Thomas W
Timo
Torch
Ulf Jonsson
vasil
Vaxian
vladi mazzilli
wastehl
Weston
William Kim
William N.
William Stehl
Wesley Venis
The aforementioned have contributed financially to the continuing triumph of 4hv.org. They are deserving of my most heartfelt thanks.
Registered Member #9252
Joined: Fri Jan 04 2013, 06:27AM
Location: Andromeda
Posts: 253
Hello, I have been thinking of replacing the typical SSTC/DRSSTC controller with an arduino board, Like the UNO or the Mega 2560, Would one of those programmed to give a pulsed signal that's the exact resonant frequency of a specific coil work as a viable controller? I am pretty sure you would need some Mosfets to amplify the output if you want to switch IGBTs, I am also sure you can set duty cycle and also play music Is that viable?
Due to the way the uC functions and its lack of a RTC it cannot provide a stable enough stream of pulses for direct driving a TC. Likewise, you can't even precisely time any pulses shorter than 1mS or so. You start seeing delays not accounted for in code from the instruction execution time that muck everything up. There are a few libraries out there that user timer.1 built in timer chip but you're restricted to fractions of the 16MHz oscillator up to 1MHz in roughly 100KHz steps.
Registered Member #9252
Joined: Fri Jan 04 2013, 06:27AM
Location: Andromeda
Posts: 253
Sigurthr wrote ...
Due to the way the uC functions and its lack of a RTC it cannot provide a stable enough stream of pulses for direct driving a TC. Likewise, you can't even precisely time any pulses shorter than 1mS or so. You start seeing delays not accounted for in code from the instruction execution time that muck everything up. There are a few libraries out there that user timer.1 built in timer chip but you're restricted to fractions of the 16MHz oscillator up to 1MHz in roughly 100KHz steps.
For example, For 56Khz Using timer 1, You can set the prescale to 1 and just set the compare match to 142 Are you saying that using Timer 1 will give more reliable results ?
It's more reliable but it isn't nearly reliable enough for TC operation. You're going to get hard switching and missed/extended pulses in the pulse train. I tried it once with a simple SSTC at around 300KHz and the bridge output looked horrid because a SSTC bridge does not tolerate running on the capacitive side well at all (below resonance). I wouldn't try it on a DR coil ever. Maybe at 56KHz there won't be as many errors in the pulse train, but my experiments didn't show it to be promising enough to try.
Also, you can't account for the dynamic load that the streamers present on the secondary and their detuning effect. This isn't a huge issue, I've run SSTCs off of a VCO before, and in some applications it is actually better than real feedback as output power fizzles out to nothing in case an on-looker comes too close and tries to touch the output. In terms of performance though it can't compare to feedback.
Registered Member #9252
Joined: Fri Jan 04 2013, 06:27AM
Location: Andromeda
Posts: 253
Hmmm, It should be noted that the arudino i have is the Mega 2560, So i have a couple more 16 Bit timers, Timer 3, 4 and 5 in addition to Timer 0, 1 and 2 I think there should be a way to make the signal more reliable. Maybe have 2 timers running at the same frequency and then they are " Checked " against each other providing a cleaner, More reliable signal? If 1 timer makes 5 mistakes in 5 places, The other makes 5 different mistakes in 5 different places, Checking them against each other should result in a more reliable signal.
Registered Member #9252
Joined: Fri Jan 04 2013, 06:27AM
Location: Andromeda
Posts: 253
Sigurthr wrote ...
Sounds like it is worth a try. I only have an UNO so it was already beyond it's capabilities (I'm sure I didn't write the most economical code).
Maybe also, Just maybe, We can make it auto tuning by setting the compare match to a variable, Said variable changes according to feedback from an antenna/bottom of resonator Maybe..
Registered Member #30
Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706
I've seen a uC based driver that works in just this way, and it was successful, however it is a serious real-time programming challenge. A DRSSTC burst lasts about 200 microseconds and within that time frame you have maybe 20 switching instants that you have to get right to within maybe 1-2us. And, you are aiming for a moving target, the resonant frequency of the coil changes during the burst as the streamer develops.
The driver I saw used a Cypress programmable system-on-chip (PSoC) and many of the timing functions were accelerated by custom hardware.
Registered Member #9252
Joined: Fri Jan 04 2013, 06:27AM
Location: Andromeda
Posts: 253
Steve Conner wrote ...
I've seen a uC based driver that works in just this way, and it was successful, however it is a serious real-time programming challenge. A DRSSTC burst lasts about 200 microseconds and within that time frame you have maybe 20 switching instants that you have to get right to within maybe 1-2us. And, you are aiming for a moving target, the resonant frequency of the coil changes during the burst as the streamer develops.
The driver I saw used a Cypress programmable system-on-chip (PSoC) and many of the timing functions were accelerated by custom hardware.
I would mainly be aiming for a continuous operation on a regular SSTC, A fiery thick arc is more interesting than interrupted DRSSTCs to me
Registered Member #30
Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706
In that case, the control problem is much easier. No need to worry about missing the zero current switching points as an untuned primary SSTC doesn't have zero current switching to begin with. The Arduino would probably work out fine.
This site is powered by e107, which is released under the GNU GPL License. All work on this site, except where otherwise noted, is licensed under a Creative Commons Attribution-ShareAlike 2.5 License. By submitting any information to this site, you agree that anything submitted will be so licensed. Please read our Disclaimer and Policies page for information on your rights and responsibilities regarding this site.
Would this be a viable controller?
