Adaptive Active Power Sharing Techniques for DC and AC Voltage Control in a Hybrid DC/AC Microgrid

Abstract

This paper deals with the ac and dc dynamic voltage control in a hybrid dc/ac microgrid (MG) with central and distributed battery energy storage systems (BESSs), applying a power sharing mechanism between the different devices in the MG. The MG is composed by a multiport transformation center and two fixed frequency three phase ac nanogrids (NGs) coupled to a dc bus through three-phase power electronic converters. The system pursues to minimize the dependence on the utility grid and the stress in the MGs central BESS, while increasing the power handling capability and the overall system stability during islanding condition. In order to approach the proposed aim, two main concerns are studied in this paper: An adaptive power sharing mechanism between the dc bus and the ac NGs for dc voltage control, and the design and implementation of an ac dynamic local voltage compensator based on distributed energy storage system. The proposed techniques are validated through simulations and experimental results.