RE: Long Pulse IGBT GDT design

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Steve Conner" <steve.conner-at-optosci-dot-com> 

 >If drive voltage
 >is 30Vpk to pk, results in a V*t product of 9000V-usecs (typical GDT
 >product is in 200-500V-usecs).

This can be handled by simply using more turns on the transformer.
Unfortunately, then the leakage inductance tends to get excessive, leading
to sluggish rise and fall times and/or excessive ringing.

It might be worthwhile investigating a transmission line transformer. This
is wound with coax cable- the screen is the primary and the core is the
secondary. This gives very low leakage inductance at the expense of high
inter-winding capacitance.

A variant with even lower leakage inductance is the ribbon cable transformer
where all the even numbered cores are connected in parallel to form the
primary, and all the odd numbered ones likewise form the secondary. But this
has even higher interwinding capacitance, and considerably worse isolation
than the coax version (the insulation is thinner and only PVC) I don't
imagine for a minute it could take 2.4kV...

Steve C.