The success on forecasting the performance of PV systems, it lies in depicting the non-linear behavior dynamics of its I–V curves, as a direct consequence of the variations in the operational conditions, where the photovoltaic system is set up. Throughout this work, authors address the physical–mathematical basics, and the assumptions made, so as to propose a theoretical approach, on purpose of describing the dynamics concerning to these systems. Findings, as well as the manuscript novelty, they comprise a full model deduced by subsections dealing with the phenomena under analysis; all them derived as function of the irradiance and module temperature.