Search

This study is concerned with presenting control strategy for interlink converters in hybrid microgrids. When both ac microgrids (AC‐MGs) and dc microgrids are in the vicinity of each other, they can be interconnected via ac–dc converters, known as ICs, making it possible to exchange energy between two grids. Common methods employed in IC control strategy use frequency variation and CCM in their structure. This method requires the frequency variation at IC ac‐side to be large, leading to poor power quality and stability of AC‐MG. Furthermore, CCM does not directly regulate the IC ac‐side voltage, which again deteriorates the IC ac‐side voltage quality. The proposed strategy is based on droop method, similar to what is used in the autonomous control of sources in an AC‐MG. This technique uses voltage‐controlled method and does not need frequency measurement in its structure. This considerably improves the voltage quality of AC‐MG. The derivation of appropriate droop characteristic is explained. Time‐domain simulation is used to verify the performance of the proposed method. The small‐signal stability of the system is studied. It is shown how by introducing a proper virtual impedance, the small‐signal stability of the system can be improved. [ABSTRACT FROM AUTHOR]

Abstract—This article proposes a method that enables ideal sharing of reactive power among converter-based micro-sources in a microgrid with a decentralized control strategy. Power sharing must be properly performed among micro-sources to avoid circulating currents or overloading. Using conventional droop characteristics to achieve power sharing is not satisfactory, as system asymmetry will greatly impact the quality of sharing. In the proposed method, droop characteristic parameters are modified upon a change in system operating point such that ideal sharing takes place after the modification process. Simulation results are presented to show the validity of analysis. [ABSTRACT FROM PUBLISHER]