negative loss

Question

Hi Kris, I have a similar problem, too. But my current value in the error is normal. However, junction temperature is way higher. But I do not believe that the error is in the heatsink. I compared my xml file with a provided model`s xml files. They are similar and with the provided files I have also the similar errors. Sometimes the error is not in igbt, it is in diodes or in the turn off losses.

Comments

Are you able to include your circuit model here? Or you can send it along with the XML files to support@plexim.com. Thanks.

Answer 1

Your conduction loss table specifies 0.646V drop at 125º and 0.576V drop at 175º (for 50A, which is close to your operating point of 46A). At T=589.6º (at which point your IGBT has long gone into flames) the voltage drop is extrapolated to a negative value, resulting in (theoretical) negative conduction losses.

So your problem is not a negative conduction loss but a too high IGBT temperature.