Stability Enhancement of Decentralized Inverter Control Through Wireless Communications in Microgrids

This paper proposes a power sharing based control strategy which incorporates the information of the total real and reactive power generation of all DG units and evaluates the performance of the proposed control strategy based on small-signal stability analysis.

Abstract

Abstract—Decentralized inverter control is essential in dis-tributed generation (DG) microgrids for low deployment/oper-ation cost and high reliability. However, decentralized inverter control suffers from a limited system stability mainly because of the lack of communications among different inverters. In this paper, we investigate stability enhancement of the droop based de-centralized inverter control in microgrids. Specifically, we propose a power sharing based control strategy which incorporates the information of the total real and reactive power generation of all DG units. The information is acquired by a wireless network (such as a WiFi, ZigBee, and/or cellular communication network) in a decentralized manner. Based on the desired power sharing of each DG unit and the acquired information of total generation, addi-tional control terms are added to the traditional droop controller. We evaluate the performance of the proposed control strategy based on small-signal stability analysis. As timely communication may not be established for a microgrid with low-cost wireless communication devices, two kinds of analytical models are devel-oped with respect to negligible and nonnegligible communication delays, respectively. Extensive numerical results are presented to demonstrate the system stability under the proposed control strategy with respect to different communication delays. Index Terms—Delay, droop control, inverter, microgrid, smart grid, stability, wireless network. I.