A Distributed Framework for Minimizing the Asymmetrical Power Request in Multi-Agent Microgrids With Unbalanced Integration of DERs

Microgrids (MGs) are initiated in power systems to speed up the integration of the independently operated distributed energy resources (DERs) into the network. In this regard, in multi-agent microgrids (MAMGs), independent agents aim to operate their resources, while the MG operator (MGO) coordinates independent agents to address the operational issues and ensures reliability of the system. In an MAMG, the high integration of single-phase DERs as well as their independent operational scheduling could result in the asymmetrical power flow in the upper-level system. Respectively, addressing the asymmetrical power request of the MAMGs by exploiting the scheduling of DERs seems to be essential due to the limited flexibility capacity in the upper-level power network, which would finally improve the operating condition of the power system. Consequently, this paper aims to develop a transactive-based scheme to minimize the conceived asymmetrical operation of MAMGs. Accordingly, MGO employs transactive energy signals to minimize the asymmetrical power request of the MAMG by exploiting the scheduling of DERs, while ensuring the privacy of independent agents. Eventually, the proposed framework is applied on an MAMG test system to study its efficacy in alleviating the asymmetrical power request from the upper-level system.

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Novel Universal Power Electronic Interface for Integration of PV Modules and Battery Energy Storages in Residential DC Microgrids

This paper introduces the novel concept of a highly versatile smart power electronic interface for fast deployment of residential dc microgrids. The proposed approach has bidirectional power flow control capabilities, wide operating voltage range, and high efficiency resulting from the topology morphing control utilization. This enables universal compatibility with the majority of the commercial 60- and 72-cell photovoltaic modules, as well as the efficient charge/discharge control of the 24 V and 48 V battery energy storages using the same hardware platform. The proposed concept features fully autonomous operation where switching between the photovoltaic and battery interfacing modes is automatically done using the input source identification algorithm. Moreover, the proposed universal interface converter employs droop control and solid-state protection, making it fully compatible with the emerging standards and requirements for power electronic systems used in dc microgrid environments. A 350 W prototype was developed and tested in the residential 350 V dc microgrid with droop control to validate the proposed concept experimentally.

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