There are 2 commonly used protocols for DC Rapid Charging an EV conversion.
|Chademo uses a separate socket to the ac charging port. This is found on Nissan Leaf.
||CCS combines the AC charging port with 2 additional pins for DC charging and comes in 2 different socket type, type 1 more common in USA and the type 2 more common in Europe.|
Another way may be using a TP-Link TL-PA4010 ("AV500") and repurposing it as a CCS EVCC.
A third method may be to a board that contains an STM microcontroller and a QCA700x IC.