SCR triggering for soft starter

hello,

am designing a soft starter for three phase induction motor, i will be using the Ardiuno to trigger the SCR's in the following way:

i will use an opto-SCR to trigger the main SCR which will control the voltage on a 400v line, and i will use the Ardiuno to trigger the main SCR through the opto-SCR, this will provide a great protection.

i will be using anti-parallel SCR's on each phase line , which mean i have to trigger 6 SCR's , two on each line.

i need the ardiuno to do the following functions (to be extended but this is what i need for now):

  • An interrupt/reset input, which takes a signal from a zero voltage crossing detector, this interrupt/reset will be the "order to start/reset" for the Arduino to trigger the SCR's as programmed.

  • Outputs to trigger the opto-SCR's, this needs a pulse generator, so i need the Ardiuno to generate pulses (with specific pulse width) for the issue of triggering.

  • An input, which sense different voltages (from a potentiometer), in order to change the triggering angle of the SCR's for each specific voltage as programmed.

i hope i can get help with which best component and best method/pins/tactic to use the Ardiuno with , to trigger the SCR's.

and it would be grateful if someone would suggest the most suitable way to connect the opto-SCR between the Ardiuno and the anti-parallel SCR's. ratings are not big issue.

sorry to write in details, but i hope it will be helpful for others who search the same subject and helpful for readers to understand what i need.