With the advances in high power converter technologies, photovoltaic (PV) power has been integrated into the utility system in greater pace in recent years. This paper aims to provide a broad overview of the various grid-connected PV system configurations and their power converter technologies for applications in single- and three-phase utility power systems. Grid-connected PV systems presented include module-integrated, string, and centralized configurations. Single- and three-phase power converters discussed include full-bridge (with an additional switch in the DC link and back-to-back IGBT on the AC terminals), and neutral point clamped converters. The synchronization techniques for grid-connected PV applications are discussed in this paper. An improved method to detect the grid frequency and voltage magnitude for single-phase system is introduced. More importantly, harmonic distortions resulting from the operation of grid-connected photovoltaic systems are addressed and analyzed. Methods for reducing harmonic currents using three types of passive filters, L, LC, and LCL, are presented. The LCL-filter design guidelines for a specific PV system are presented in detail. The effectiveness of these filters is demonstrated on 3 kW and 50 kW photovoltaic systems.