A PV system consists of many cells connected in series and parallel to provide the desired output terminal voltage and current. This PV system exhibits a nonlinear I-V characteristic. Masoum et al., introduced a verified model for silicon solar PV panel. In this paper, this model is modified to integrate the electrolyzer and FC/UC system as shown in Fig. 2. The PV cell equivalent model, which represents the dynamic nonlinear I-V characteristics of the PV system shown in Fig. 2, is used within the hybrid system. The parameters used in the mathematical modeling of the PV system are as follows: