It has been very difficult to control power electronics with proper tool selection and knowledge of driving it
i would like to share some knowledge to trigger scr with the help of 16f877a. since i have to control firing angle of scr with help of pic i have to fully isolate the power side and mcu side power supply this can be easily done with moc3021 opto ic which is used to fire or trigger scr and triac. On the power side i hade only on scr so for the full wave support i have pre rectified the line neutral to give me DC supply you can check out my design in the proteus file. before we start please check out this site’s to gain some extra knowledge how they work.
The source code of this project was written in c language using ccs compiler. An inverting type schmitt trigger is used to give an interrupt to mcu at every falling edge of the pulse. after the falling edge pulse interrupt a timer is started. and after the timer interrupt occurs the firing pulse is given to scr. the timer values vary according to the analog read from the mcu pin so the degree of firing or triggering changes according to the analog value
for 50 Hz it should be nearly 8 ms delay for 0 angle and 0 ms for 180 angle. Since i have used 10 bit adc i can control firing angle upto 180/1023 = 0.17441860465116279069767441860465 angle accuracy.
below is the video i have added after fully successfully testing the circuit
Please note since this projects is related with power electronics you should have proper knowledge of working with 230 volt ac and do it at your own risk.
Download Project source code and related files
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