IGBT Failuaren in Mediam Frequency Inverter

[Riyazahmad]

We have 50KW, 10KHz, Pillar make induction heating equipment.
We are facing problem of frequent Failuare of Costly IGBT.
Can anybady suggest test points or resources to find out the cause.
Thanks in advance. :roll:

 

[Styx]

What voltage is your link?
What current is the inverter rated for

What voltage is the IGBT rated for
What current is the inverter rated for

What kind of packaging is the IGBT's - 6pack? (3phase), 4pack (single phase), induvidual

What IGBT's are failing? Is it a phase leg (ie potential shoot-though), or what

How are they failing? use a DVM to check for Collector-Emitter impedance (short or high impdance), check the anti-parallel diodes, check the gate capacitance and gate impedance.

If you can crack open the module and examine the die (by eye). Overcurrent should be big craters, over-voltage should be stress/fracters at the corners along the edge of the die =since this is a 50kW inverter shold be easy to see with teh naked eye


What is the topology used? what cind of control (voltage, current?)

How long is it running before failure (after a few minuits ~ control problem, after a few days/weeks ~ control/thermal problem)

hope this is of help

 

[Riyazahmad]

IGBT Failuare

Thanks Styx,
Your reply greatly helpful me to solve the problem.
Let me reply to your doubt,

Voltage of line i.e. Bus DC Voltage 480V
Current of inverter rated for 110 Amps
Voltage of IGBT rated for 1200V
Current of Inverter rated for Ic 200 Amps and Icm 400 Amps.
IGBT pakage : 2 transister in each package i.e. 2 IGBT's are used.
Inverter shows Power Supply not ready
Collector-Emitter impedance short after failing.

I am inprocess of crack and check by eye and same will mentioning in next post.

Topolgy used is current contol.

It will running 4-5 week before failure.

Expecting more HINTS, IDEAS from you gaus.

Bye,
Riyazahmad. :roll:

 

[jnegowski]

when you replace the igbt do you replace all or just the one that has failed ? Do you use the same manufactor and same part number ? are your replacements the exact fff as the one's that were the orginals ? some designs requier that the series resistor on the gate must change in value to keep the switching speed correct. just some hints

joe