Please release switch after starting simulation! In other case initial transformer current will be paranornally high.
Full bridge MOSFET switch mode power supply with high frequency forward transformer 563V to 0,5 - 48V (potentiometer gives reference voltage). First right OpAmp is error amp, then error signal goes to PID controller and two last OpAmps works as comparators for PWM modulation. Deriverate unit is needed to decrease LC circuit oscilations. Output bridge has two inductors instead of lower diodes to increase efficency. Similar circuits works in forklifts batteries chargers. Have a fun!
It looks very simple but I was working on it for one week to achive nice step response.
Normally output capacitor is bigger but design would work very slowly.