Re: Please help ! IGBT exploded ...

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

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

Hi Sean,

Actually, I did a low voltage testing ( at 24V ).
The output waveforms from IGBT H bridge had square pulses and I could see
ringing
after the rising/falling edges of the output waveforms.
My mistake was that I didnt properly check whether both the IGBTs in one leg
are
turned ON at the same instant. (not a good way of designing circuits !)
Please post the schematic for a dead time controller as you told.
Thanks a lot !


----- 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: Sean Taylor <sstaylor-at-uiuc.edu>
 >
 > IGBTs will tend to be a lot slower than FETs - and have a lot higher gate
 > capacitance.  I'm guessing you had shoot through, and the immense current
 > blew the IGBTs.  ALWAYS ALWAYS do low voltage testing before applying the
 > full voltage - use a variac and monitor the input current, or run from a
12
 > VDC source first and check all the waveforms - see if the output devices
 > have the right gate waveforms, and are in fact turning on and off at the
 > right times.
 >
 > If you'd like, I'll post a schematic for a simple deat time controller so
 > that you can add a small amount of "off" time in between pulses while
 > waiting for the IGBTs to turn off.
 >
 > Sean Taylor
 > Urbana, IL
 >
 > On Mon, 08 Mar 2004 07:45:01 -0700, Tesla list <tesla-at-pupman-dot-com> 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 ?
 > >
 > >
 >
 >
 >
 >
 >
 >