In order to meet standard specifications in terms of power quality and safety for grid-connected systems the phase angle, the amplitude and the frequency of the grid voltage are a critical piece of information. Phase locked loop (PLL) algorithms are very important for grid synchronization and monitoring in most of the grid-connected power converters system. This paper presents a performance comparison of single-phase synchronization techniques: Synchronous Reference Frame-Phase Locked Loop (SRF-PLL), Enhanced Phase-Locked-Loop (EPLL), Quadrature-Phase Locked Loop (QPLL) and Second-Order Generalized Integrator - Phase Locked Loop (SOGI-PLL).