قباد شفیعی

Microgrids represent a new structure in power systems, characterized by the presence of distributed generator (DG) sources. These systems have prompted the reconfiguration of traditional power systems to accommodate the unique capabilities of microgrids. One of the most significant features of microgrids is their ability to operate in an islanded mode, which enables them to supply the required energy during disturbances in the main grid. Power sharing is an essential requirement for islanded microgrids, and it presents a substantial challenge. Insufficient power sharing leads to unbalanced load sharing, which can cause damage to both consumers and the grid during grid-connected operation, as well as create voltage instability conditions. Appropriate power sharing enhances microgrid performance and controllability during faults. Achieving proper power sharing among DGs in a microgrid necessitates suitable control schemes. In microgrids comprising multiple DGs, droop control is a widely used technique for power sharing purposes. Droop control maintains voltage and frequency at different values compared to reference levels and distributes active and reactive power among DGs. While active power is proportionally shared among DGs according to their rated power, reactive power sharing is prone to errors due to differences between line impedance and inverter output impedance. To achieve precise power sharing using droop control in microgrids, it is crucial to compensate for these impedance differences. The proposed control approach in this work is based on the implementation of virtual dynamic loops as a modifying term for effective power sharing. Employing virtual dynamic loops is a promising strategy for improving the performance of conventional droop control methods. The primary objective of this work is to utilize virtual dynamic loops to achieve accurate active and reactive power sharing in microgrids. The application of virtual dynamic loops reduces the dependency of droop control on line impedance and inverter output impedance while preserving the simplicity of the droop control structure. Furthermore, the straightforward design of virtual dynamic loops enhances system reliability. In this work, various types of virtual dynamic loops, such as virtual impedance loops and virtual control loops, are employed to accomplish precise power sharing and improve the performance of microgrids