Hello i would like to ask how is compensation done on switching PSU with wide range variable output voltage (from zero to several hundres of volts). I have succesfuly (I guess) simulate my own design with simplis (picture #1). I am using TL494 which needs non-inverting type 3 compensation, i have played around values calculated thanks to @VerbalKint in this topic TL494 compensation. I have tried to calculate values at my own. I have follow steps in book "Switching Power Supplies A to Z from Sanjaya ManiktalaL" in chapter "Feedback Loop Analysis and Stability" page 481, second edition. Delivered values need some sort of tweaking, There was need to increase number of iterations in POP... ) Failed run at Picture #4. I actually dont know if this is the correct way to calculate it, i played with values anyway, result #5. So if @VerbalKint is reading this topic can you please tell in which book did you find the right procedure? Maniktalal procedure at #2, used values at #3.
The main question is how its done at wide range output voltage. If you look at picture #6 (using setup from #5) i have changed reference voltage to have 20V at output (with resistor divider/ potentiometer) and as you can see phase and gain is completely different. How to face this? I have seen lab PSU from HSPY on ALI with range 0-1000V. How to stabilize this? Also they are probably using for reference voltage PWM output from MCU connected to RC network maybe with buffer at output? If someone know more details about that i would appreciate it. A Thanks very much