In article , Arie de Muynck wrote: [....]
I haven't thought this through but:
It seems to me that the problem could be helped by adding a bit of complexity to the snubber circuit. This added stuff needs to do this:
When the triac is switching on, the snubber circuit is basically open circuited.
When the triac is switching off, the snubber initially is just the capacitor. As time passes the snubber starts to look resistive.
I have something like this in mind:
! --- C1 --- ! ! -------+------- ! ! V --- --- C2 ^ ! !! ! +----!!---- S1 ! ! !! ! / ! ! +/ o-+ ! X1 ! ! +--????---- ! ! ! --- V ^ --- ! ! -------+-------- !
C1 is the capacitor that is normally part of the snubber.
The bridge and C2 makes a way to soak up the energy without having to turn it into heat right at that instant. X1 is something that gets rid of the energy. S1 closes when the voltage hits zero.
Yes, I know this actually won't work! It does seem that something with a low parts count should be possible.