An Improved Control Scheme for Power Sharing between Distributed Power Converters in Islanded AC Microgrids

Power sharing in islanded AC microgrids is a growing area of interest for researchers. Droop control methods are basic de-centralized methods of power sharing between power converter nodes in an islanded AC microgrid. However, these methods have certain drawbacks including the need for a secondary control layer to correct deviations in voltage and frequency caused by droop action in primary power sharing control loop. Alternatively, multiagent consensus based control methods utilize localized controls at each converter node such that all nodes work to reach a consensus upon required parameters through communication based sharing of measured values. However, using these methods, reactive power sharing is not satisfactorily achieved. Moreover, the control response tends to be slower and in-accurate. This paper proposes a distributed consensus based control scheme to ensure proportional sharing of both active and reactive power between distributed converters in an islanded AC microgrid, whilst also restoring voltage and frequency to their nominal values. Effectiveness of the proposed method has been verified through simulation studies in MATLAB Sim power systems.