Series-Resonant DC-DC Interface Converter for Battery Integration into DC Microgrids

The paper focuses on the galvanically isolated series-resonant dc-dc converter (SRC) operating at low values of the quality factor of the resonant tank. This topology is considered as a bidirectional step-up front-end dc-dc converter with buck-boost functionality for integration of battery energy storage in dc microgrids. The main aim of the study is to develop a universal dc-dc converter for the parallel connection of batteries to the dc microgrid. The paper presents a closed-loop control system of the SRC capable of regulating the current of a battery and softly changing the power flow direction. The developed closed-loop control system is based on droop control for parallel operation in the dc microgrid. Experimental results show the performance of the developed converter in operation as a battery front-end interface converter in the dc microgrid. Depending on the voltage in the dc microgrid, the control system regulates the current of a battery and changes the power flow direction for storing energy in the battery or supplying the dc microgrid.