Research on Filter Enhanced Phase Locked Loop based on Multiple Second Order Generalized Integrator

Abstract

In the process of low voltage crossing of photovoltaic grid-connected power generation system, the traditional three-phase phase-locked loop cannot accurately lock the phase when the grid fault occurs. Aiming at the deficiency that the filtering ability of traditional complex filter (CCF) cannot meet the requirements of power grid, this paper proposes a three-phase voltage phase-locked loop structure based on second-order generalized integrator (SOGI), and optimizes the signal quality before entering the phase-locked loop. In the simulation, the phase-locking effect and the acquisition ability of positive and negative sequence components of the improved PLL are verified respectively, and the effectiveness of the proposed structure is verified.