OK, so, yesterday I tried to do what I wanted:
1) Have a RC filter with R=65 kOhm, C=0.47 uF. I read the instantaneous value from this filter and use as a input to make decisions when to turn high frequency arc starter on or off. I say, if my measured bus voltage is more than 45 volts, turn it on, and if it is less than 40 volts, turn it off.This gives me a very quick reaction time (for me) average, with ripple of about 2%.
2) For display purposes (I have a serial display), I take the value above and further average it using exponential moving average. That's so that display would not endlessly oscillate between similar numbers.It worked absolutely great. The HF relay engages right after I switch voltage, with no lag like before.
I think that I will do the same with the current input, as well.
I also spent half the evening battling a seeming bug in the microcontroller, where if I define a function taking a real number, and call it, everything goes haywire.
i