Hi Richard,

Thank you for the link. I’ve been reading a lot about TEC controllers lately but did not find this one.
I know my goal might be too ambitious but so far the results are encouraging.
All I did so far is trying to create a poor man’s PID system at its simplest form.
Based on the temperature difference (act_temp – set_temp) I change the output level of my PWM.
It might be a little abrupt in the beginning but after the temperature stabilizes there will be only small steps in the voltage output (about 0.15V per step). That puts me lower than maximum admitted ripple for the TEC (5 – 10%) and it is only an occasional change not continuous like a non-filtered AC to DC voltage.
If I can find the right range (more testing is needed and unfortunately I must travel a lot for the next few weeks) I might not have to turn the TEC OFF at all and only lower the output voltage to maintain the temperature, which in turn keeps the TEC happy.
Since I’m having the fans paralleled with the TEC I must keep this min_pwm adove a certain value. Some brushless fan manufacturers recommend 5V as minimum running voltage and 7V as minimum starting voltage. That is the reason why I’m starting the system with a kick.
Not sure if this is the best approach reason for which I’m posting here.

Thank you for the input. I hope others will be interested in this project and bring new ideas to the table.

Nick