A Novel Three-Port DC-DC Converter for Integration of PV and Storage in Zonal DC Microgrids

Abstract

Energy conversion process of distributed renewable energy resources and energy storage devices highly depends on the DC-DC converters as interfaces. Reducing the number of conversion stages can lead to less complex energy conversion process. Multi-port converters with their flexible structure and control strategy are good candidates for this purpose. A management and integration study of PV/battery in zonal DC microgrids is presented in this paper. Moreover, a novel isolated three-port converter with continuous input current called three-port DC-DC interface is presented. Also, a zonal DC microgrid architecture based on three-port DC-DC interface is presented and discussed. An efficient four-layer control strategy for power flow management in DC microgrid is presented and discussed thoroughly. Simulations are conducted under various operation modes and loads to demonstrate the capability of proposed interface and the presented methods and strategies. The proposed three-port DC-DC interface converts and manages the power flow in the DC microgrid with high efficiency values of 91.8% and 95.6% for two-stage and single-stage conversion processes, respectively.