That’s why it took several months to solve the problem. The Harvi needs a varying AC current to determine the current in the cable (using a CT clamp). Getting a simulation of this signal took some working out.
My solution uses an AC transformer (AC to AC) and an LED/LDR combination to control the AC current. I couldn’t find another way to do it. The LED is pulsed by the microcontroller and this varies the LDR resistance in the AC side. That is the principle but it also took several hundred lines of code.

What system have you got in terms of panels, batteries, and inverter?