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• Unbalance load sharing in islanded microgrids using negative sequence power droop. • New consensus-based secondary-level control scheme for cooperative adjustment of droop gains. • Cooperative controller reduces voltage unbalance at sensitive load buses. • Small signal analysis of the consensus dynamics for a converter-based Microgrid. • Simulation model demonstration for a 4-bus microgrid power system. It is common for industrial and commercial microgrids to experience high levels of load unbalance when operating in islanded mode, which degrades the real output power capability of inverters, causes power quality problems, and impacts on the protection regime. Conventional droop control methods are not designed for sharing of unbalance power where multiple inverters are used, and existing proposals for negative sequence power sharing have several practical disadvantages which are identified. This paper proposes a novel secondary scheme for cooperative adjustment of negative sequence droop gains for voltage source converters. The new design provides an option for sharing of unbalance power, while also correcting voltage unbalance at sensitive buses. In contrast to other designs, the scheme proposes hierarchical unbalance control using a fully distributed architecture. It is robust to communication network failure and adapts to impedance changes in the electrical network. A simulation model of the proposed scheme is demonstrated using MATLAB/Simulink for a reference case. [ABSTRACT FROM AUTHOR]

• High frequency (HF) emissions are a new power quality concern. • Photovoltaic (PV) inverters are major HF emission sources. • No PV inverter models suitable for HF studies are found in current literature. • A generic method is proposed to develop black box models of PV inverters for HF studies. • The models developed have less than 6.5% errors with 95% confidence. There is a growth of high frequency (HF) emissions in the range of 2–150 kHz (also known as Supraharmonics) in electricity distribution networks, primarily due to the increasing number and capacity of AC grid connected equipment having power electronic interfaces. Although PV inverters are a major HF source in electricity distribution networks, PV inverter models that are suitable for HF emission studies are yet to be developed. To this end, a generic method that can be used to develop HF models of small-scale (<5 kW), grid-tied, single-phase PV inverters using a black box approach is presented in this paper. Accordingly, HF models of three PV inverters that are commonly used in domestic and commercial installations are developed assuming standard network conditions. It is shown that these HF models are capable of successfully capturing the HF performance of the selected PV inverters under a wide range of operating conditions. The outcomes of this work are expected to broaden the knowledge pertaining to the HF emissions in the frequency range considered. [ABSTRACT FROM AUTHOR]