Among a large number of photovoltaic applications, we are interested in the cathodic protection. It is one of the solutions used for the structures subjected to corrosion, mainly in oil and gas industries. In this work, optimum design sizing and system description are presented. Based on the design of a solar photovoltaic powered minicathodic protection system, a standard configuration of the photovoltaic system using a combination of four panels (two in series and two in parallel), has been derived. This standard size option must be matched at any cases of the cathodic protection station. For this purpose, an adaptive circuit, which is a voltage regulator with variable output, has been developed. Usually, cathodic protection systems work with constant current output, which is the necessary condition to procure immunity voltage of the structures against corrosion. The major difficulty to achieve this goal is the variations in the surrounding medium resistivity. To overcome this difficulty, several systems of control and regulation intended for cathodic protection system powered by photovoltaic energy have been designed and discussed. In our case, we propose an adaptive adjustment of the buck-boost converter output voltage by means of the microcontroller pulse width modulation output. In this paper, a complete design of the adaptive cathodic protection system using photovoltaic energy is carried out.