IMPORTANT, I am not trolling, and if I am asking stupid questions,
that's due to my ignorance and malice.
A while ago I asked for suggestions regarding making a square wave
inverter to convert a DC TIG welder into an AC TIG welder.
Many things happened since that time.
1. I bought a real DC TIG welder for $9.99. See it here.
It is a 3 phase welder that I run off my homemade phase converter.
My page with more pictures and my experience so far
2. Spent many times its cost of $9.99 on cabling and various welding
doodads and consumables.
3. I played with arc welding, trying to learn to weld (see above links).
Now, I am a little closer to the aforementioned inverter project. I
bought four Toshiba IGBT, mounted on a heatsink:
My plan is to follow what this guy did:
and to use two IR 2011 gate driver chips, appropriate caps and
resistors, and to use a Wavetek 171 to drive the logic inputs of these
chips. Wavetek 171 can make square waves of arbitrary frequency, set
digitally, and adjust pulse width.
Note that each IGBT is a complete half bridge, so I need just two, out
of the four that I bought. My welder is a 200 A constant current
welder, so it would not exceed the 200 A limit of the IGBT. I set
welding current digitally, using a digital potentiometer on the
control panel of the welder. Thusly, I could, supposedly, get away
with using just two IGBTs, one for each half of the H bridge.
The welder's welding voltage is 28V and OCV is 85V. The IGBTs are
rated for 1,200 V.
Since wavetek 171 can put out pulses of adjustable width and
frequency, I can use it as the control of this inverter. Wavetek's
output will be the input of the IR2011 chips.
For power, I will try to use a computer power supply.
I read various relevant application notes and schematics, by now.
16 years ago