Fuzzy logic adjustment for power sharing in wind and PV-based isolated microgrid

Power flow control is one of the major issues in parallel connected inverters of an isolated microgrid. Droop control is considered to be the well-known method for managing power flows between micro-grid converters in decentralized manner. In this work, the fuzzy logic based improved droop control technique is developed to control the power flow between voltage source inverters connected in wind and solar photovoltaic (PV) based isolated low voltage AC microgrid. A proportional resonant (PR) voltage and current controllers are designed to control the current and voltage output of the voltage source inverter (VSI) connected with the dc battery. In the proposed micro-grid model, one battery is associated with wind turbine generator (WTG) system and another battery with PV system. The fuzzy logic controller (FLC) adjusts the droop coefficient values of the VSI connected with each DC battery according to its state of charge (SOC) and the power difference between total load and renewable generation. This technique demonstrates the robustness of the control system even in sudden load change condition and improves the system frequency response in wind and PV based isolated microgrid.