Re: Please help ! IGBT exploded ...

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

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

Sorry Steve, I didnt give the information about the rectifier I used.
I had a bridge rectifier and its output (Positive and Ground) was
connected to IGBT terminals. Thanks for pointing out this.

Thank you Steve and Jan for helping me in debugging my setup.
Please give me some more suggestions ...

Thanks.


----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Tuesday, March 09, 2004 12:44 AM
Subject: RE: Please help ! IGBT exploded ...


 > Original poster: "Steve Conner" <steve.conner-at-optosci-dot-com>
 >
 >  >I connected the terminals to 220V line and neutral and switched ON
 >  >The IGBT exploded immediately !
 >  >Any advise for me ?
 >
 > It sounds like you connected it to AC :-0 You're supposed to put the 220V
 > line through a rectifier before you feed it to the IGBT. With AC, as soon
as
 > it goes negative, the two diodes inside the half-bridge pack will short
the
 > line and neutral together, kablooie!
 >
 > However, those diodes are pretty chunky. If there was a fuse in the 220V
 > line, then the fuse should have blown before the diodes did. So maybe the
 > cause of death was something else. Perhaps your gate drive circuit didn't
 > have enough deadtime*, and the IGBT died from massive shoot-through? (Old
 > IGBTs switch OFF slowly and need some deadtime to recover. Start with 50%
 > deadtime and decrease it until the no-load current draw starts to climb.)
 >
 > *deadtime= time when both IGBTs in the halfbridge are OFF
 >
 > Steve Conner
 >
 >
 >