you show a partial schematic with 5 IGBT
then a hand drawn optical coupler and FET driver
then a drawing of the FET driver driving one FET
then a drawing of the optical coupler
please draw at least a block diagram showing input, all power components,
the drive configuration for all IGBTs, a timing diagram showing when the various IGBTs are on or off, including dead time
also, a brief description of how its supposed to work
the better information you provide, the better answer you will get.