SSTC
4
A Single PCB Full-Bridge
Solid State Tesla Coil
|
Solid State Tesla Coil 4 Platform
My SSTC 3 project turned out to
be a good experience in developing my first single-PCB tesla coil. It went pretty
well, but I wanted a little bit more power and had several ideas I
wanted to improve upon for the design. As a result, I decided to modify the SSTC 3 to utilize SMD components,
and added another half
bridge to form a full-bridge for the main inverter. The result is SSTC 4 - a single PCB,
General Purpose Solid-State Tesla Coil Platform capable of
swappable interrupters like a graphics card on a computer, and
configurable for us as a DRSSTC with the addition of a tank cap.
- Note: this page is still under construction!
More to come soon.-
SSTC 4 Project Status: Tested at 120VAC and 240VAC! (Oct 2015)
*Boards for Sale*: I had a bunch of leftover boards
left from the development of this project. Please see my
sales page for more information.
SSTC 4 Specifications (July 2015):
- Compact footprint and mounting holes to fit and mount
exactly in almost all ATX power supply cases (only because they do make
for a cute box!)
- Laminated Full-Bridge topology with low bus
inductance, accepting 4 of your favourite TO-247 IGBTs or MOSFETs
- Robust discrete push-pull MOSFET driver
- Commercial drop-in GDTs for easy assembly, and great performance
- Generous heat-sinking for the full bridge
- General purpose feedback allowing Antenna, Primary Current, Secondary
Current or direct Secondary feedback
- On-PCB logic transformer with switch for easy dual voltage (120 or
240VAC input) operation!
- Swappable interrupters / controllers like GPUs on a motherboard -
compatible with SSTC 3
- Safety protection, bleeder resistors, Under Voltage Lockout, Fuse (5 x
20mm)
- Add one resonant capacitor and an external bus cap to convert this
into a DRSSTC (has flip-flop for zero current turn-off!)
- Added spade-connectors for easy external connections
22 Sept 2015
Project Description
The SSTC 4 single-PCB Tesla Coil was developed as a
full-featured all-purpose Solid State Tesla Coil platform for building a
compact yet powerful full-bridge coil, all on a single PCB. This
revision was developed as an improvement over my reliable and proven
SSTC 3 half-bridge platform, and builds upon it with many improvements.
Full-bridge operation allows significantly more power output compared to
a half-bridge.
Like the SSTC 3, the SSTC 4 platform was designed
primarily to be run from the sine-wave ramp from the mains ('ramped
mode'), but can be easily converted to regular SSTC operation with the
addition of a bus cap, and also into a DRSSTC with the addition of a
tank capacitor. The board was designed to be easy to hand-solder despite
using some SMD components.
Schematics
Full schematics for SSTC 4 are available here. Hopefully this will be
useful to those looking to develop their own designs.
I also developed a very simple test interrupter to go along with SSTC 4.
SSTC 4 was designed primarily to be run in ramped-mode like SSTC 3. This
simple interrupter offers a dual functionality of a mains zero-crossing
detector (via the 12V transformer) and also allows of optical input from
an external controller. In order to reduce parts count, the analog
staccato interrupter used in SSTC 3 has been updated to use only an
optocoupler + a small Atmel microcontroller (ATtiny45/85). SSTC 4's
interrupter input has the same pin-out as SSTC 3 for compatibility.
The source code for the controller can be downloaded here (source
or hex).
PCB Design
Swapping the DIP packages for SMD saved me a bit of
space on the PCB for the large heatsink and additional two IGBTs.
Some features include a laminated bus, multiple
footprints for input/output connections, and laminated gate drive lines.
Improvements from SSTC 3 include a more robust
discrete MOSFET push-pull drive for the GDTs, off-the-shelf GDTs for solder-and-play
operation (no more worrying if you got the phase right!), as well as an
integrated switch for both 120VAC and 240VAC universal operation.
Populating the boards
Finally I got the PCBs fabricated and I'm glad to say that it turned out
very nicely, and fits almost all ATX power supply boxes perfectly :-).
Admittedly, a steel ATX box is hardly the best enclosure for a SSTC
operating at a few hundred kHz, but nevertheless it makes for a cute
case.
Building a Coil
One of the first few coils I built using the SSTC 4 platform was a very
simple and small SSTC running in 'ramped-mode' off the mains sine-wave
ramp, for my friend Philip. This coil runs on 120VAC and was designed to
be a simple, plug-and-play coil which could run reliably and fairly
quietly as a very simple demo unit with zero set up time. As a result,
the coil was not strictly optimized for performance, but nonetheless
produces decent, small sword sparks and effectively serves its purpose
as a good demonstration unit!
Phil helped to take the photo above of the coil in action!
More to come soon, do check back often for updates!
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(c) Gao Guangyan 2024
Contact: loneoceans [at] gmail [dot] com |
