The air pollution was much worse, and it became necessary to replace the fossil energy sources by the renewable energies. The causes are related to reserves that can be exhausted, to pollution and their impacts on the environment. Production of toxic gases from the combustion of coal for the effect of increasing the temperature of the earth. Solar energy is a clean and inexhaustible excellent alternative. We propose a modeling and simulation of a solar system consists of a photovoltaic generator (PVG), a boost chopper, to supply a telecommunications relay station (BTS), According to the load characteristics (I = 60A, V = 48V) DC (3 kW). A stage adaptation composed of this chopper controlled by a PWM controller (Pulse Width Modulation) is used to control the optimal operating point (MPPT) and optimize system performance using Matlab / Simulink.