Bert,
The recent "design ideas" discussion led me to an announcement of a IGBT
that does not require a snubbing circuit
There have been IGBTs out there for quite some time, that clamp overvoltage not by avalanching in the main device, but by intentionally turning the device partially on, by means of a zener diode between collector and gate. It's not a new thing.
Prime examples of such devices are the IGBTs used in engine ignition systems. See the datasheet of the STGB20NB37LZ, to learn about it.
It makes perfect sense to extend this technique to higher frequency operation, in switching power supplies.
It's true, of course, that there will be more power dissipation in the IGBT, than when using a snubber. But who cares? What matters to a manufacturer is getting the job done at the lowest possible cost. If a snubberless IGBT mounted on a slightly larger heatsink is cheaper than a plain IGBT mounted on a smaller heatsink plus a power resistor, high voltage capacitor and fast diode, they will go for it. And typically the overall efficiency is better when using such a clamped IGBT, than when using a snubber, because the IGBT clamps just the necessary minimal amount, while a conventional snubber also consumes some energy when the voltage is well inside the allowed range.
Manfred
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