An Improved Algorithm of Grid-Connected Inverter for Islanding Detection

As the fact that the existing positive feedback active frequency drift (AFDPF) islanding detection algorithm has contradiction between detection time and total harmonic distortion (THD). In this paper, a variable coefficient positive feedback active frequency drift algorithm is provided, which based on the analysis of traditional positive feedback active frequency drift method. The simulation model of active frequency drift is established based on MATLAB/SIMULINK, to testify the function of improved algorithm. It can be seen that the proposed method not only detected island effect effectively, but also had less blind detection.