In this thesis, the basic properties of PV cells are first described. By connecting PV cells, usually in series, a PV module is obtained, whose lifetime is typically 25 years. With PV systems, it is important that the cells are correctly connected to meet the voltage and current requirements and that they are protected from atmospheric influences. Then the ideal PV model with current source and diode as well as the photoelectric effect is described. Since power electronics converters are responsible for most of the power losses in a PV system, methods to improve PV system efficiency are also clarified. The basic requirements for connecting the PV source to the grid and protection are regulated by international standards, with islanding protection being perhaps the most technically demanding since the inverter must disconnect the PV system from the grid in a very short time after the grid is turned off. Converter topologies for connecting PV modules to the power grid consist of power optimizers and microinverters. As for the string exchanger, all processed topologies use the bridge topology (H-bridge) as a starting point and represent its upgrade. Central exchangers are explained using NPC topology. The methods of synchronization with the grid using Fourier analysis and using a phase-locked loop, which provides information about the phase angle and amplitude of the grid voltage, are also explained. The basic structure of the phase-locked loop, its block diagram and response are presented, and the corresponding key parameters are given.