Grid Voltage Synchronization for Distributed Generation Systems under Grid Fault Conditions

Abstract

Distributed Generation (DG) System is a small scale electric power generation at or near the user’s facility as opposed to the normal mode of centralized power generation. In order to ensure safe and reliable operation of power system based on DS, grid synchronization algorithm plays a very important role. This paper presents a Double Synchronous Reference Frame (DSRF) phase locked loop (PLL) based on synthesis circuit for grid synchronization of distributed generation (DG) system under grid disturbances aimed to provide an estimation  of the angular frequency and both the positive and negative sequences of the fundamental component of an unbalanced three-phase signal. The design of this PLL is based on a complete description of the source voltage involving both positive and negative sequences in stationary coordinates and considering the angular frequency as an uncertainparameter.