Communication-Free Power Management Strategy for the Multiple DAB-Based Energy Storage System in Islanded DC Microgrid

Abstract

Along with the development of the renewable energy, such as the photovoltaics and the wind turbine, the energy storage system (ESS) is becoming as a critical part for the renewable-based microgrids. In this article, dual-active-bridge (DAB) dc-dc converter with bidirectional power flowing ability, wide soft-switching range, and ultrafast dynamic characteristic is adopted for integrating multiple energy storage units (ESUs) for balancing the power flowing between the renewable energy and the loads in a islanded dc microgrids. For the multiple DAB-based ESS, a communication-free power management strategy is proposed in this article to maintain the dc-link voltage for the islanded dc microgrid, and high robustness of the dc-link voltage can be ensured when the output voltage of energy storage equipment, the load condition, and the power sharing performance of the ESS are changed. The proposed strategy also ensures seamless ESU plug-in or plug-out operations. Finally, the small-scale simulation model and experimental platform are both employed to verify the effectiveness of the proposed communication-free power management scheme.