Solid State Tesla Coil Theory, et. al.
Updated Nov. 5, 2004
Pertinent discussions (IMO) from The Tesla List
Other Miscellaneous and Useful Info
http://www.richieburnett.co.uk/sstate2.html Richie Burnett's Solid State TC Theory
Dr. Gary Johnson's site with an extensive set of Tesla coil "white papers" covering all aspects of design: http://www.eece.ksu.edu/~gjohnson/tcchap1.pdf This is the link to Chapter 1, increment the chapter number to get to all 9 chapters. I downloaded and printed all 9 chapters today, a full 3-ring binder of great theory and practical data.
James Pawson's site on SSTC design: thedatastream.4hv.org/gdt_design.html has moved or disappeared gives much background on circuit design and fabrication for MOSFET driven SSTC's.
Jan Wagner's Tesla coil site with extensive circuit development info on SSTC's: is no longer active hut.fi/~jwagner/tesla/. Scroll down till you get to the SSTC section. The last section on "self-resonant" SSTC design is very interesting, as it describes a driver circuit that continuously varies its frequency to match the resonant frequency of the secondary as its resonant F changes due to streamer loading, nearby objects, etc.
Check the Fairchild site for an "IGBT Basics" paper; a bit more complex than the "datastream" website, but interesting nevertheless.
IGBT Data and Sources
http://www.dynexsemi.com/products/application_note/igbt.htm
http://www.irf.com/technical-info/whitepaper/choosewisely.pdf
IGBT Manufacturers include (all have web presence, via Google).
On-Semiconductor
Fairchild Semiconductor
International Rectifier
Semikron USA
Infineon (ex. Siemens)
Dynex Semiconductor
Westcode
IXYS
Powerex
Toshiba
Mitsubishi
ST Microelectronics
APT (Advanced Power Technologies)
Fuji Semiconductors
Other Relevant Stuff
Date : Tue, 22 Jun 2004 20:13:43 -0600. Subject : Re: Self-Resonant Driver Boards (DRSSTC, ISSTC, etc...)
Original poster: "Eastern Voltage Research Corporation"
> Good, because the way you had put it, it seemed as though the circuit was only to protect the driver chips and not
>the
transistors in the bridge, I guess that would go hand in hand though...
Correct.
> It might be wise to allow some sort of heatsinking on the driver chips, in case they would get warm, But if you're
>using the UCC27321, I don't think that would be needed, as they have a wider temperature operating range.
Heatsinks really aren't needed. If you do the calculations for power
dissipation at 10-15% duty cycle running 20nF gate loads (-30 to +30V swings)
with the UCC chips, there really is no heat dissipation at all.
Remember heat dissipation of the gate driver is:
C * V^2 * Freq * Duty * DividingFactor
C = capacitance of gate loads (typically 20nF + 20nF per paralleled set)
V = 60V (Yes, you are swinging from -30V to +30V with the current configurations
that Steve and I use)
Freq = 50-200kHz (depends on coil)
Duty = 15%
Dividing Factor = (ON Resistance of Drivers/(SeriesGateResistor+ON Resistance
Drivers)).
Dan.
Date : Tue, 22 Jun 2004 20:13:07 -0600. Subject : Re: Self-Resonant Driver Boards (DRSSTC, ISSTC, etc...)
Original poster: "Eastern Voltage Research Corporation"
Really nothing to do with pulse width but more a concern of duty cycle.
PRF of the pulse (interrupter) frequency has little effect as its such a low
frequency to begin with.
I wouldn't run more than a 10-15% duty cycle using the UCC drivers and those
large FAIRCHILD IGBTs.
You have four UCC drivers (two 321 paralleled, and two 322's paralleled) and
driving four (4) 15-20nF
gate loads with the Fairchild IGBT's.
If you ran 100% duty cycle at 100kHz the dissipations on the UCC chips would be
very high and burn them up very quickly. Dan.
> What would be an example of too wide pulse width and too high PRF which would
damage the UCC drive chips.
Finis