Virtual Impedance‒Based Adaptive Droop Control to Improve Reactive Power Sharing for Inverter-Based Microgrids

Authors

Abstract

With recent advances in power-electronics, inverter-based microgrids are gaining great attention. Droop control is one of the main methods to share the real and reactive power among distributed energy resources (DERs) in an islanded microgrids. Due to different characteristics of microgrid feeders, reactive power sharing is not fully accurate and, consequently, some DERs may face overload. To address this problem, this paper presents a droop-based method using virtual impedance concept in the DER control system. The resultant voltage drop on the virtual impedance increases reactive power sharing accuracy. To adjust this virtual impedance, the local controllers of DERs exchange the required data with the microgrid management center by using the low bandwidth communication links. Afterwards, through the proposed virtual impedance‒reactive power droop characteristic the value of virtual impedance is calculated. The slope of this characteristic is adaptively adjusted based on the microgrid load. To verify the effectiveness of the proposed method, the researchers have tested various scenarios on the benchmark low voltage microgrid network.

Keywords


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