Re: Please help ! IGBT exploded ...

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

Original poster: Mike Poulton <mpoulton-at-mtptech-dot-com> 

Tesla list Wrote:
 > Original poster: "Rajesh Seenivasan" <rajeshkvs-at-hotmail-dot-com>

 > Dear forum members,

 > Yesterday I was experimenting with an old IGBT - BSM100GB60DLC, which I got
 > from my friend,
 > for my SSTC. I used the same gate driver I designed for IRFP460 MOSFET H
 > bridge.
 > I connected the terminals to 220V line and neutral and switched ON my gate
 > drive circuit.
 > The IGBT exploded immediately ! I did not give any load to IGBT. The H
 > Bridge's
 > output terminals were not connected to anything !
 > The gate drive was at 70kHz approx.
 > I observed that the gate drive waveform was not clean like a square wave.
 > Any advise for me ?

Which transistors exploded? Was it two in series (top and bottom on
one half of the bridge)? If so, then shoot-through was certainly the
problem. Was the bridge phased correctly? If you were turning the top
and bottom IGBT's on simultaneously, that would explain it. This could
also be the result of a very unclean or poorly timed gate drive. Check
the gate drives for a series pair of IGBTs on a dual-trace scope and
ensure that they are never on within 100ns or so (depending on IGBT
specs) of one another.  Significant ringing on the gate is definitely
to be avoided -- a 10 to 33 ohm resistor in series with the gate helps
this greatly.

-------------------------------------------------
Mike Poulton
MTP Technologies
mpoulton-at-mtptech-dot-com
KC0LLX (70cm AM ATV, 33cm/12cm FM ATV, Omaha, NE)