Performance of PLL based DSGCPS and FLL controlled SSGCPS under normal condition and different grid faults: A comparative study

This paper presents two separate studies to address the increasing need for renewable energy sources in the grid to cope with the rising energy consumption. Firstly, a Double Stage Grid Connected Photovoltaic System (DSGCPS) based on Phase Locked Loops (PLL) is developed using Matlab-Simulink. Secondly, a model of a single-stage grid-connected photovoltaic system (SSGCPS) controlled by a frequency locked loop (FLL) is created with comparable environmental parameters and a loading pattern. The research compares the active and reactive power flow dynamics and DC link voltage fluctuations of both systems. Results indicate that the SSGCPS is the preferred option due to its lower hardware requirements. However, it has a lower performance in cases of grid faults compared to DSGCPS. Moreover, the study analyzes the Total Harmonic Distortion (THD) of both models, a crucial factor for performance analysis. The comparative study shows that DSGCPS performs better than SSGCPS during fault in terms of THD. In conclusion, it can be inferred that both models have unique advantages and disadvantages, which are contingent on specific operating conditions