Will this work for building a bench supply ?

[Externet]

120VAC---->isolation transformer---->rectifier---->160VDC---->filtering---->pot.controlledIGBT---->output 0-to-100+VDC

 

[ZipZapOuch]

The IGBT is better as a switch then a regulator.

What kind of loads are you thinking about? I'd go with a very high frequency Switcher design but it depends on what you're after.

Also, if you get a step-down transformer you can clip some waste off of your filtered 160vdc you're planning to use to feed your 0-100v regulator. 60v is a lot of headroom. 120 to 100 transformers are pretty common.

 

[Externet]

What kind of loads are you thinking about?

Charging 12V, 21V, 40V and 80V batteries. Mostly not beyond 5 Amperes.
What do you refer to as 'common' 120-to-100VAC transformer in defunct equipment that can be salvaged ?

 

[crutschow]

You don't need a filter after the rectifier if you are charging batteries.
They don't care if the charging current is smooth or not.

You could use a variac feeding a rectifier to get a variable output with high efficiency.
Of course the variac is not isolated so that must be considered.
Using a GFCI plug (example below) attached to the variac cord would minimize the chance of electrocution.

 

[Externet]

Good. Have variacs, have GFI plugs. Will see...

 

[crutschow]

You would likely want to use a Schottky bridge rectifier.

 

[schmitt trigger]

Years ago, 1983, I built such a system to charge a UPS battery bank, 48 lead-acid cells. With an equalization voltage that would require 112 volts @ 30 amps.
Back then, SCRs were the only way to achieve that much power. But nowadays IGBTs would be the semiconductor of choice.
Operated as a switching, not linear, device. The battery doesn’t care that the current is pulsed.