This thesis analyzes a photovoltaic system with a DC-DC step-down converter without galvanic isolation, in which three different MPPT methods are used to achieve optimal PV panel power. The basic characteristics of photovoltaic panels, DC-DC step-down converter without galvanic isolation, and some of the most commonly used methods for monitoring maximum power are described. The analyzed system consists of a photovoltaic panel, a DC-DC step-down converter, a control circuit, and a working load and a battery at the output. The PV panel voltage is regulated using a PI controller whose parameters are adjusted by the trial and error method. The effectiveness of the considered MPPT algorithms was tested using a system simulation model created in the MATLAB-Simulink software package. Three simulations were performed, one for each of the considered MPPT methods, covering wide ranges of insolation and PV panel temperatures. For better comparison, the same insolation and temperature values were given in all three cases, at the same time points. Simulation results are presented and analyzed in the last chapter of the paper.