In the paper energy supply system based on photovoltaic (PV) arrays was described. Also models of a single PV cell and a voltage boost converter were described. The boost converter was used for holding an appropriate work state of the PV arrays associated with its maximum power point level in various work conditions associated with irradiance level and the arrays temperature. Finally, comparison of two strategies of voltage level control in PV arrays system was put forward. These strategies were used to attain the maximum power point, and to define the work conditions, in which described control algorithms are the most effective.