[SOLVED] 600V/2A Diode with a very high VF of 9.07V. Anyone know what kind of diode this is?

[Johansen]

Neutral point clamped makes sense. its called a 3 level inverter.

to put a 9 volt clamp across the switches makes no sense. unless the purpose of doing that is to somehow split up the energy recovery network into two separate networks, one for turn off, one for turn on. but then you wouldn't use an igbt (because the switch never sees more than 9 volts), you would use an xx volt, xxx amp mosfet.

 

[FvM]

to put a 9 volt clamp across the switches makes no sense. unless the purpose of doing that is to somehow split up the energy recovery network into two separate networks, one for turn off, one for turn on. but then you wouldn't use an igbt (because the switch never sees more than 9 volts), you would use an xx volt, xxx amp mosfet.

It's O.K. to say, you don't understand why the module uses a zener clamp across the IGBT. Saying it makes no sense sounds somewhat ignorant in my opinion.

The switch of course "sees more than 9 volts", the clamp is only limiting the IGBT reverse voltage as the schematic in post #14 clarifies.

A brief description of the concept can be found in a Vincotech application note.

 

[lawcuenca]

The diode is clearly showing up as a diode/zener combination, which clarifies the reason for unusual high "forward" voltage.

If it is a diode/zener combination, is it safe to assume that the rated VF of 9V is equal to the sum of the zener voltage and the forward voltage drop of the included diode?

Thanks!

 

[FvM]

is it safe to assume that the rated VF of 9V is equal to the sum of the zener voltage and the forward voltage drop of the included diode?

That's a plausible explanation for the specification.