[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
RE: SS Variac (Low Pass Filter)
- To: tesla@xxxxxxxxxx
- Subject: RE: SS Variac (Low Pass Filter)
- From: "Tesla list" <tesla@xxxxxxxxxx>
- Date: Thu, 24 Mar 2005 17:06:52 -0700
- Delivered-to: testla@pupman.com
- Delivered-to: tesla@pupman.com
- Old-return-path: <teslalist@twfpowerelectronics.com>
- Resent-date: Thu, 24 Mar 2005 18:12:28 -0700 (MST)
- Resent-from: tesla@xxxxxxxxxx
- Resent-message-id: <FT40xD.A.QaD.7V2QCB@poodle>
- Resent-sender: tesla-request@xxxxxxxxxx
Original poster: "Steve Conner" <steve.conner@xxxxxxxxxxx>
>The basic topology is a full wave DC bridge in
>series with hot leg, with a 600V, 40A IGBT across +/- of bridge as a
>commutating
>switch.
Before you do any more work on this, please give some thought to the $64,000
question- When you're driving an inductive load (like a NST etc) through
this device, the current will try to keep flowing when the IGBT turns off.
Where will it flow?
I tried to figure it out but couldn't think of any path for it. I concluded
that the diode bridge or IGBT would be destroyed by inductive kickback when
running with an inductive load, so I gave up on this topology.
If anyone can prove me wrong I'd be happy as it's a very simple and
attractive circuit. I know a guy who successfully used it to do PWM dimming
of filament lamps but of course they are pure resistive loads.
Steve Conner