SCR gate controller circuit using arduino

Hello.. I m practically new to arduino. I m doing a project about controlling a phase of SCR's in H bridge rectifier. I have to design on how to control the firing angle of the SCR. Based on my review, i have to produce pulse using the arduino and interupt signal from a zero crossing detector. From the slow learning, i m trying to use the PWM pulse to trigger the gate. But i cant seem to have an idea on how to vary the firing angle where the pulse trigger the SCR. Example, If i set the firing angle to be 45 degree, the pulse from arduino after receiving the interupt signal, start producing pulse on the 45 degree. Can someone show me some examples perhaps.

Forget the PWM that will not help you. You need to detect the zero crossing point of the AC and then delay after that to give you a phase angle.

Is there a tutorial for it?

Just google Arduino zero crossing detector And there are lots.

Thank you so much... much appreciated....