Droop Controlled Microgrid With Intelligent PV-DSTATCOM for Power Quality Improvement

A droop controlled microgrid composed of a battery energy storage system (BESS) and a photovoltaic based distribution static compensator (PV-DSTATCOM) is developed in this study to improve the power quality of a microgrid. Owing to the high penetration rate of the renewable energy source-based distributed generators, the extensive usage of inductive loads and unexpected load change, the power quality issues, including unbalanced currents, current harmonics, and lagging power factor (PF), have become severe challenges in the microgrid. Consequently, a novel control scheme of PV-DSTATCOM is developed to overcome the power quality issues in the droop controlled microgrid. The developed PV-DSTATCOM combines the power generated from PV system with the reactive power compensation of a DSTATCOM to enhance power quality and grid reliability. In other words, the developed PV-DSTATCOM owns the angular frequency/active power ω-P droop characteristic and the ability to reduce the total harmonic distortion (THD) of the current, correct PF, compensate the reactive power for voltage support, and mitigate the three-phase unbalanced system currents of the microgrid. Furthermore, to effectively improve the transient response of the reactive power compensation and the performance of the PV-DSTATCOM during load variations, an intelligent online trained Petri Legendre fuzzy neural network (PLFNN) controller is proposed to replace the conventional proportional-integral (PI) controller. Furthermore, the network structure and the online learning algorithm of the proposed PLFNN are derived in detail. Finally, the effectiveness of the proposed PLFNN-based PV-DSTATCOM to improve the power quality of the microgrid is verified by the experimentation.