Energy management of distributed renewable energy sources for residential DC microgrid applications

This paper proposes a low voltage (400 Vdc) distributed renewable energy fed DC microgrid structure for a residential system, which uses DC voltage for the electronic appliances. The distributed energy sources—solar photovoltaic (PV) and wind energy are considered as input sources. The output power from these sources is stochastic in nature. An efficient energy management and switching circuit is designed to control the power flow from the sources with a high gain DC-DC converter as the main component. The output power regulation is achieved by means of controlling duty ratios of the switches in the proposed high gain converter through PI controller. The control algorithm effectively converts the unregulated DC power from the solar PV and wind into regulated DC for driving a DC load connected in DC-microgrid. The energy management and switching circuits account for seamless operation of the DC microgrid under various modes when one or all the sources and loads are connected directly at the DC grid link. The designed energy management and switching circuit also ensures the power balancing in the proposed system. The proposed DC microgrid structure is simulated using MATLAB Simulink. The performance of the proposed high gain converter for the DC grid link voltage regulation is analyzed under source power variation and dynamic changes in load for various operating conditions. The proposed DC microgrid structure is validated using simulation results.