The paper deals with the modeling and comparison of the performance of photovoltaic (PV) generators with panels from different technologies. The generators are part of an experimental platform at the Technical University of Sofia and operate in real weather conditions. The modeling of the PV modules is based on the Durisch's model using two approaches. The comparison of the models with measured data shows good agreement. We observe that a limited number of characteristic days can be used for the modeling of the PV panels. The inverter's model is based on the manufacturer data. The comparison with the measured data shows good coincidence. Finally the combination of modules' and inverter models is compared with experimental data and we observe a good level of overlap.