grid tied pv system grounding to sub-panel

i am installing a grid tied pv array system using enphase m250 micro-inverters that connect to an a/c shut off switch and then feed to a sub panel via 12-3 wiring.

the sub-panel wiring from the primary load center in the system has only 3 wires; neutral is bonded to ground at the primary load center.

the sub-panel is about 120’ from the primary load center. the pv array is about 50’ from the sub-panel.

in order to pass inspection and to be safe, how should the pv array ground be incorporated into this configuration?

thanks much.