Could someone please give me some advice on my PV model in Simulink.

I am trying to model a PV system connected to 2MW Grid. The goals are to scope the output power and monitor frequency on the grid.

Now I have several questions:

1. g input for DC-AC inverter should be control but I do not know what kind of control should I do. I just want the inverter to convert DC voltage from PV to AC.
2. I have irradiance data to be used for this model, but I do not know how to input it to workspace block. Somehow I could not change the Data parameters in'From Workspace' block.
3. What block should I add so I could monitor the effect of PV power fluctuation on the frequency of the Grid?
4. The Grid should be set to 2 MW, but I am not sure whther to use RLC Load or Dynamic load?

I would really appreciate it if someone could give me some advice.