RE: SSTC transformers

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Leigh Copp" <Leigh.Copp@xxxxxxxxxxx>

In actual practice 2kV rail to rail would almost definitely result in
very expensive beach sand if you used 1kV devices.

There is always some slew and/or propagation difference between the
diagonally opposite switches, so they will not share voltage evenly.
This completely neglects any switching transients that are bound to
occur during hard switching.

Typical application practice for hard switching involves at least 1.8 *
Vdc per device, and 2x is quite common.

Best practices for gate drive on large IGBT's involve floating +/-15VDC
power supplies, and fibre optic isolation (Agilent HBFRx521 is the usual
tool of choice). All of this is per device. It's pretty expensive, but
so are large IGBT's.

Floating the entire driver guarantees that you won't have any common
mode transient immunity problems.

Leigh



Original poster: "Mccauley, Daniel H" <daniel.h.mccauley@xxxxxxxx>


The voltage rating of the IGBTs is for when the devices are turned off.
When the devices are turned on, there is virtually zero volts across
the device. But yes, you could use 2000V rail-to-rail voltage with an
h-bridge made of 1000V IGBTs, however there would be no margin.

Also, assuming you mean GDT transformers, you'll have to wind your own.
Most commercial off-the-shelf GDTs have too much leakage inductance to
be
useful for SSTC use.

Dan
"DRSSTC : Building the Modern Day Tesla Coil " Book - Available May 12,
2006
Check www.easternvoltageresearch.com for more details . . .



In an H-Drive configuration, two semiconductors are in series with
the load at all times.  Could you then supply the drive with twice
the voltage that a single semiconductor could handle (ex. Drive made
of 1000V IGBT's supplied with 2000V).  Also, where is a good place to
find a transformer for an SSTC coil?

Andrew