Influence of Filter Inductance on Synchronization Stability of Grid-Connected Converter

With the increased penetration of renewable energy, grid-connected converter systems face the increasing risk of losing synchronism under large disturbance. The influencing factors of synchronization stability have begun to receive attention. This paper examines the impact of filter inductance on synchronization stability in grid-connected converter systems. First, an equivalent circuit model of grid following (GFL) converter considering current transient is established. Based on this model, it is expounded that the filter inductance must be considered for synchronization stability analysis. Second, the relation between filter inductance and frequency deviation of phase-locked loop (PLL) is derived when a fault occurs, following by the influence of filter inductance on synchronization stability. It is concluded that with the increase of filter inductance, the PLL frequency deviation increases, as well as the synchronization stability of the system decreases during the fault. Finally, the theoretical analysis has been validated through simulation using Matlab/Simulink.