Single-phase distributed generation synchronization with a distorted or weak grid

Fast and accurate synchronization of power electronics interfaced distributed generation to the grid or a microgrid is an important step in the management and utilization of the distributed energy resources. Several synchronization algorithms have been proposed to improve the phase tracking of the grid voltage. However, when the grid is weak or distorted, the synchronization process may suffer from poor frequency regulation. Therefore, Sliding Discrete Fourier Transform Phase-locked-loop (SDFT-PLL) algorithm is proposed to extract an accurate angle of the fundamental voltage while rejecting the harmonics in a distorted or weak grid. The SDFT-PLL algorithm and simulation results to validate this method are presented in this paper.