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Snubber cap issue

0 votes
Snubber  cap issue.

There is current spike..

I attached the file.

Do you know what is the problem?
asked Mar 17 by oming0731 (21 points)

1 Answer

0 votes
There is no problem.

The capacitor is charged to 500 Volts, then short-circuited with a series resistor of 0.0001 Ohm. I=U/R.

What do you expect? (And why do you need the snubber cap in the first place?)
answered Mar 17 by Oliver Schwartz (447 points)
First, Why do I need the snubber cap...

I am developing a soft-switching inverter. (I am developing ARCP topology)

It is one of the parts of it.

Second, I expected the capacitor to prevent fast switch voltage transition so reduce the turn-off loss due to the snubber cap.

And without the resisor, the circuit is not working...

Is there any advice?

Soft switching implies that you turn on the switch when the voltage across it (and the capacitor) is zero. If you did, there would be no current spike. In all other cases - well, you can't defy Ohm's law.

However, your series resistor is ridiculously low. The on-state resistor of a semiconductor switch is several orders of magnitude higher.

Another hint: R2/R3 and C_dc have no effect when connected in parallel to an ideal voltage source.