IGBT Module gate collector terminals short

[hridyai90]

Hi Friends,

I am currently using semikron IGBT modules for three phase VSI circuit and it was working fine.
But one fine day i found the gate driver is showing fault and after inspection of the circuit i found a short between gate and collector terminals of the igbt. I was not able to find the exact reason for the same. The DC voltage was around 200V and i had not released the switching signals. Also I have a protection circuit for overcurrent and overvoltage.

Can some one help me on this issue with an immediate solution?

Thanks in advance

 

[D.A.(Tony)Stewart]

YOu would need to show a lot of info to get help.
Schem., layout, photos, datasheet links, etc.

How do you know the OVP protects the devices? Have you tested that? with a 3kV pulse? Joules?

What tests have you not done?

SEMiX IGBT modules are sensitive to electrostatic discharge, because discharge of this kind can
damage or destroy the sensitive MOS structure of the gate.

Did you know risetime of ESD can be in picoseconds. Does your filter rise time protection allow clamp circuits to respond in time? or not?

Have you tested for ESD yet?

 

[hridyai90]

Hi,

I have tested the protection circuit which provides protection if overcurrent happens in any of the three phases and also over voltage occurs in the DC bus. I have been using the same hardware structure consisting of protection card, semikron semitrans igbt module and skyper 32R driver module for the past 3 months. Everything was working as expected. I did experiments yday till late night and today, after charging the DC bus, while powering the
control circuit, the dirver in the B phase was showing fault. On inspection it was found that the gate terminal of the
top switch of the module was opened (accidentally!! Not sure how it happened). And later realised that the switch collector was shorted with the gate terminal.