I am running a simulation of solar generation for every zip code in the U.S. using SAM and its LK scripting interface. I am also performing the same simulation with Sandia's PVLIB (
pvpmc.sandia.gov/applications/pv_lib-toolbox/) model. It is my understanding that SAM's Sandia PV Arary Performance Model should yield the same results as PVLIB if the weather inputs are the same. However, I have tested this using TMY3 weather files, and the AC generation output is different, even with the exact same parameter settings. Is there a possible explanation for different results?
Also, are there any available comparisons between SAM's various models (i.e., PVWatts, Sandia, and CEC) that might indicate which of these is the best model to use for countrywide simulations of AC output from residential PV systems?