Hi,
please tell exactly how you want to process the zero cross signal.
your post#19 is your
exact description? Two words, a couple of lines, some letters...
There is no information where the signals come from and no information how you decided to generate them.
I assume there is a big lack of understanding how it should work.
Reread the whole thread. Read the recommended documents.
* there is no point of time where you can switch ON all three phases to get "zero cross switch"
* therefore you need to start with two phases only
* therefore you need to know the zero cross point of those two phases
* after switching ON those two phases there is voltage at the star point.
* switch ON the third phase when it's voltage is equal to star point voltage
Use pulse trains.
If you want to design such a circuit you need to be able to calculate/draw/simulate somehow the resulting voltages and currents.
You may use a paper and a pencil, Excel, matlab....whatever.
Otherwise I recommend you to start with simpler designs.
Klaus