This thesis deals with the regulation of the voltage of a load supplied from a photovoltaic panel using two different DC converters, a step-up and a step-down DC converter. The basic principles of photovoltaic conversion and photovoltaic cells are described, as well as the topology and operating principle of the converters used. Simulation models of the considered systems were created in the Matlab Simulink software package. The basic components of the model are the photovoltaic panel, the DC converter, the control circuit and the load. The load voltage regulation was implemented using a PI regulator. The operating type of the load was used in the simulations. The optimal parameters of the PI regulator were determined by the trial and error method. The responses of the regulated variable to sudden changes in the associated reference value and to the occurrence of disturbances in the system in the form of sudden changes in insolation were considered. The paper presents simulation results for both considered DC converters, obtained with previously optimized PI regulator parameters. The system operation was tested at different levels of insolation and load resistance with different constant levels of load reference voltage and PV panel temperature. The tests were carried out for three different PV panel temperatures ranging from 0 °C to 50 °C.