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short circuit protection of IGBT?
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coppercone2:
So I read if a IGBT has a short circuit current and even if it manages to turn off, you can still have failures.

Assuming you are running something like 300A igbt's, is there some other component you can put ahead of the H-bridge to break the circuit fast enough without this problem?

It would have to work within a microsecond or so of the detection. The idea would not be to turn the h bridge off but to cut off power to the H-bridge.

I thought maybe some kind of SCR or whatever other weirdness there is that would not be appropriate for power conversion (it would not have to work frequently). And maybe something on the bus bar connected to ground that would short it out while its in the middle of turning off?
max_torque:
google "desaturation detection"

coppercone2:
Even  the  short-circuit  current  is  successfully  turned-off,
short-circuit   failure   could still   happen   after   several
microseconds,  which  is  called  delayed  failure  in  [31].  It  is
verified  by  experiments  and  numerical  simulation  that  large
leakage current leads to the thermal runaway [37]. A “critical
energy  (EC)”  is  proposed  to  explain  the  mechanisms  of
catastrophic failure and wear out failure under repetitive short-
circuit operations [38]. When short-circuit energy is below
EC,
IGBT  may  survive  for  more  than  10^4 times repetitive short-circuit  operations  before  failed.  However,  when  short-circuit energy is far beyond EC, IGBT may fail after first short-circuit due to thermal runaway

thats with the detector I am pretty sure

won't cutting power be better then trying to power it down while its over loading? thats what i think. I get the feeling messing with the gate is a bad idea if its really bogged down? it says something about 'local overheating' too.
jbb:
And what kind of switch would you use for removing power from the H Bridge?
PartialDischarge:
Forget it, the least expensive way to protect an igbt is to let the igbt break, that is besides designing a system with enough tolerances.
If there was a switch fast enough to cut the supply it would cost 10x the igbt and add additional inductance to the whole setup, besides weight and size. So in power switching no one does that.
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