Hi everyone
After long break i would like to resurrect topic.
I changed LC filter to 300uH inductor and total capacity 9000uF plus common mode choke. Also i bought Analog Discovery 2 to measure bode plot.
Quick recap:
Topology - Half Bridge
PWM Controller - SG3525
Mosfet Drivers - HCPL3120
Transistors - IRFP460
Rectifer - 4 x 60CPQ150
Voltage after diodes on max PWM - 43V
Target output voltage 0-30V (regulated)
Feedback OP-AMP - TL3474C
Used compensators - Type 2 , or Type 3
Load = about 1ohm
LC_Filter schematic

I have charts bode plot with out compensator, and few charts for compensator type 2 and type 3. Can you evaluate where put zero and pole looking to uncompensated chart. Also i would ask you to evaluate attached charts for compensator type 2 and type 3.
Feedback loop uncompensated Output = 5V

Feedback loop uncompensated Output = 12V

Type 2 compensator Output = 5V

Type 2 compensator Output = 12V

I have hope that toogether we will resolve feedback loop compensation problem, and acquired knowledge will be usefull for others designers