Bidirectional DC-DC Converter for Battery Storage Systems with Support for Mitigation of Voltage Imbalance in Bipolar DC Microgrids

Nowadays DC microgrids provide a valuable alternative to AC technology in the context of electrical energy distribution grids and increasing energy demand. One of the main structures of DC microgrids are the bipolar solutions. Although presenting several advantages over unipolar solutions, the major problem is the voltage imbalance that can appear. This paper presents a non-isolated bipolar DC-DC converter to be integrated in battery storage systems. The converter was designed to transfer energy between the DC microgrid and batteries, and at the same time, to support the balance of the bipolar DC microgrid. This support can be achieved in two ways, namely through the transference of the energy between the DC microgrid and batteries using only the pole that requires support for the balance or as a standalone voltage balancer. Simulations and experimental results of the DC-DC converter operating in bidirectional mode will be provided. From the presented results, it will be possible to verify the capability of the converter to operate as bidirectional interlink between the battery storage systems and the bipolar DC microgrid.