Hi,

I am reworking on my thyristor controlled power supply. I have previously used a sliding control method with deadband to regulate the output voltage. In this scheme I measure the output voltage and increase or decrease (fine or course depending upon the % error value) to obtain stable voltage. This works okay for steady load such as battery charging. However for a heavy load switching on-off the system experiences hunting. I have used a linear current transfer lookup table for firing angle computation found here http://www.tinaja.com/glib/muse109.pdf .

I would like to improve the control algorithm for better response and less overshoots (when a heavy load is removed) and undershoot (when a heavy load is connected).

I am using a Full Cycle Half controlled Bridge followed by DC choke and capacitors. I am measuring input supply, output voltage and current. The firing scheme is interrupt based. The firing angle is computed every cycle and on a zero cross it is loaded (offseted) into timer1. When timer1 rollovers the thyristors are fired. The zero cross is high priority and all the interrupt routines in asm utilizing shadow registers. My control range is between 5 degree and 150 degrees. BTW I am using a 18F452 @ 10Mhz.

My previous thread on a printer grabber went unanswered I hope I get replies on this topic.