prolem with IGBT

when i repair my melting machine .i have a prolem with IGBT and driver circuit
when i change new IGBT and turn on machine for short time IGBT to burn .
I was check signal and every thing is normal :
VGE = +-18 p-p v

please help me !

A half bridge, high frequency, resonant converter driving an induction furnace...ok

Chances are you tried to replace a warp speed IGBT that can drive around 200KHz out with a slower one, standard speed IGBTs don't get out of the audio range.

You need to measure the operating frequency and pick an IGBT that can do it.

The other thing that would cause that is if you replaced it with an identical part but did not screw it down properly. Bare minimum you need heat sink grease. Often you need good electrical insulation as well.

And it has to be tight to ensure that heat gets out of the case as these parts dissipate 50-100W (at least I assume you are looking at a multi kilowatt industrial unit, I don't think they bother with this sort of stuff at low power)

Or you have not found the root cause, which may be outside of what schematic you showed us.

Willbe said:

Or you have not found the root cause, which may be outside of what schematic you showed us.

Click to expand...

there is that ... I was going on the assumption that he drew that out looking at a power driver board. It stands to reason that he would have inspected the induction coils and connections in the mean time.

Thanks !
in my machine use water cooler ,i think it is not burn by over heat ,inductor coil is ok

thaithanh said:

Thanks !
in my machine use water cooler ,i think it is not burn by over heat ,inductor coil is ok

Click to expand...

The inductor coils are almost always water cooled... how are the IGBTs cooled?

IGBT mount on the aluminum heatsink and water flow in side heatsink.
i will tell you about i do!
today i was test my machine
signal driver IGBT is around 8-10khz ,-+18v p-p I
i connect new IGBT and it can work around 18-20A (input supply curren) when i increar power ,IGBT to short one of IGBT .
new IGBT 200A 600v
i think IGBT short is not by over curren .

You might try looking at the rise-time of your input signal to make sure
it is fast enough for the device you are using. I'd also add a counter EMF
diode to the output collector emitter of the driver transister to handle
those spikes.

If you are using the original transistor model, the driver may have a
problem driving the transistor into saturation fast enough!

Good luck!

Rob )