Convert Solar Power from the Data block to SimPowerSystems Currents ？

Recently, I am studying the mircogrid in Matlab：24-hour Simulation of a Vehicle-to-Grid (V2G) System. Here is the link: https://ww2.mathworks.cn/examples/simpower/mw/sps_product-power_V2G-24-hour-simulation-of-a-vehicle-to-grid-v2g-system?s_tid=srchtitle

Although I found a good demo, I do not really understand it. The demo is shown in the first figure that I attached. The weather data (solar irrdiance) is sent to the PV block and the PV block converts this weather data into SimPowerSystems currents. I do not understand this process.

Particularly, inside this PV block (as I attached in the second figure), there are two important equations. I think they are the keys. However, I do not really understand them. So please help me. Maybe some good reference or books?

Many thanks!

[Payam]

Did you ever figure this out? I am also interested