Active and reactive power sharing control strategy for VSGs in microgrid considering the different capacities of distributed energy resources

Abstract

Since the concept that inverters can be controlled to behave like a synchronous generator has been proposed, the virtual synchronous generator (VSG) started to become the mainstream control of distributed energy resources connected distributed system. This concept simulates the frequency and voltage regulation of synchronous generator to improve the overall stability of the medium- and low-voltage power system. Although significant research works have considered the application of VSGs in active and reactive power sharing, it seems to be that the issue of the proportional power sharing of VSGs of different capacities has not considered much in the previous works, especially when the distribution lines have increased resistive components. Such resistive disturbs the power flow and causes the power coupling. When focusing eyes on the parallel operation, VSGs need to coordinate parallel operation to increase the microgrid power quality, reliability, and for easy maintenance. Based on an improved droop control and virtual complex impedance, this study adjusts PI controller parameters to implement the proportional power sharing and decoupling for VSGs of different capacities. Simulation results are shown to verify the feasibility and validity of the control method.