[SOLVED] Neutral Point Clamping

[emaniac]

Hi

Can anybody explain me what is "Neutral Point Clamping(NPC)" in Inverters?

I referred few documents, But I didn't get a clear picture of what it is :|


Regards

 

[chuckey]

I think its to stop the neutral line in floating too far from earth potential. If the output of the inverter is from a transformer, then if a fault occurred and the live output got shorted to earth, the neutral wire would then become live, which can damage equipment.With a clamped neutral the secondary would see a short circuit and pop its trip.
Frank

 

[FvM]

It's a topology for three-level inverters

 

[emaniac]

Hi chuckey,

Thank you,

With a clamped neutral the secondary would see a short circuit and pop its trip.

I'm sorry, I don't basically understand what is "clamped neutral".
If you have or find any documents that explain NPC the better way, Please suggest me :sad:



Hi FvM,
Thank you, I found this image the other day, but I have hard time correlating the term NPC with the circuit above. Please help me figure that.

Regards

 

[FvM]

I posted the schematic to clarify what NPC basically is, didn't attempt to explain the operation principle in detail. There's quite a lot of technical articles available on the internet.

The essential point is that the AC output is connected to NP in leg state 1, through diodes and switches. You should be able to verify this by tracing the current pathes in the schematic.