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 service life 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, an ideal PV model with a current source and a diode is described, as well as the PV effect. Since power electronic converters are responsible for most of the power losses in a PV system, methods for improving the efficiency of the PV system are also explained. The basic requirements for connecting PV sources to the grid and protection are regulated by international standards, with the anti-islanding being technically perhaps the most demanding feature 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 a PV module to the power grid consist of a power optimizer and a microinverter. As for the string inverters, all covered topologies use the full-bridge topology (H-bridge) as a starting point and represent its upgrade. Central inverters are explained using the NPC topology. Methods of synchronization with the grid using Fourier analysis and using a phase-locked loop, which provides information on 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 shown, and the corresponding key parameters are given.