Re: Please help ! IGBT exploded ...

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

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

Hi Mike,

The bottom transistor on one leg of the H bridge exploded. (It shows short).
The gate drive waveform of top and bottom igbts crossed each other at 0
volts
and increased from 0 to +/-5 volts in 800ns (very slow rising edge ?).
I had 3.3 ohm resistor in series with gate.


----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Tuesday, March 09, 2004 12:42 AM
Subject: Re: Please help ! IGBT exploded ...


 > 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)
 >
 >
 >