Ignoramus965 wrote:
My objective is to make a square wave inverter for high amperage DC
for TIG welding, from a 300A CC DC welding power supply.

I would actually be content with 200A current. AC would be used for
aluminum only.

I own a Wavetek 171 signal generator:

http://www.labx.com/v2/spiderdealer2...m?LVid=2779965

Can I simply use it to drive either MOSFETs or IGBT's that make up the
H bridge?

i

No. You need a different signal for the high side drivers referenced
to the midpoint of the bridge. Wasn't this question answered already
in an earlier thread? Also, large power stages require a lot of
current to drive them. In basic EE classes, they teach you the gate
driver problem (how can a circuit with no dissipative elements still
dissipate power). You need to understand this problem before designing
gate drivers. I believe Don Lancaster has a nice article on this
matter somewhere on his web site.

Why don't you reference a working design and ask questions based on
that? This will give a reality check and stop you from wasting
people's time and generating all kinds of noise?

I have spent some time checking the following reference design out. I
am fairly sure it will work:

http://www3.telus.net/public/a5a26316/TIG_Welder.html

Sure, you can argue all day about using a signal generator or using
MOSFET's instead of IGBT's, but why don't you reference some questions
to this design. Also, you might be able to get some advice at
www.diywelder.com. There are other designs there as well.

Good luck.