Utility Synchronization of PV-WGS-BES Based Distributed Generation Microgrid Using ITOF-FLL Control Algorithm

The dynamic performance of the conventional phaselocked loop (PLL) leads to frequency divergence and oscillations in the converter’s power output. Thus, this paper implements improved third-order filter (ITOF) frequency-locked loop as an efficient grid converter control and theta (θ) extraction method for utility synchronization (US). This manages the renewable energy sources (RES) based microgrid in both standalone and utility tied mode, while feeding loads with green and uninterrupted power. This control also provides a fast and accurate assessment of the harmonics component of load currents with their respective phases of synchronization to execute microgrid in its generic utility conditions. ITOF control is implemented with a frequency-locked loop (FLL), making the control frequency adaptive. Therefore, in comparison to the PLL approach, the implemented ITOF-FLL control has reduced complexity, faster, precise in frequency tracking and easier parameter tuning. This control algorithm eliminates harmonics of load current thereby reducing the total harmonic distortion (THD) of the PCC current. Accordingly reducing the THD within acceptable IEEE 519 limits. The behavior of the ITOF-FLL control under load and generation perturbation is validated by simulation results, which demonstrates its excellent performance.