Design voltage-mode boost converter

2018-06-05 08:17:11

I am trying to simulate boost converter using voltage-mode controller as the schematic below. However, the circuit doesn't work as expected. Output voltage is supposed to be equal to reference voltage which is 8V but in this case it is only 3V.

Also the output of comparator is always 0 which means the switch is permanent OFF.

I tried to tune PI controller parameters but it doesn't help much. Is there a systematic method to design this without having to tune a lot?

Schematic:

Output voltage and inductor current waveforms:

Vsaw, VPI3, Vsw signals:

VPI1, VPI2: