Power Flow and Stability Analysis of a PV-Based Distributed Generation System with UPQC

·                    This paper proposed an Single stage 3-phase 4-wire grid tied PV system  performing the tasks of a UPQC operating with a dual compensating strategy and also  FFCL. The system PV-UPQC was built by means of two back-to-back connected three level NPC inverters. Along with providing active power from the PV arrangement the PV-UPQC system was able to perform series-parallel power line conditioning. Hence   both static and dynamic performances of the system were experimentally evaluated under disturbed grid voltage conditions including sags, unbalances and harmonics. Apart from series compensation suppression of load harmonic currents  as well as compensation of load reactive power were carried out such that an effective power factor correction was achieved. The effectiveness of the FFCL acting on the series converter current references was properly evaluated under sudden solar irradiation changes. Fuzzy logic controller is proposed in this paper for the mitigation of total harmonic distortion(THD). The proposed PV-UPQC system hence represents a promising solution to be applied to DG systems, as well as  AC micro grids too.

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