Design and implementation of a DC-DC converter for renewable energy source powered systems

Electricity systems are confronted with concurrent pressures arising from growing demand, supply security uncertainties, and carbon reduction goals. This dynamic thereby positions on-site energy solutions as a prominent focus within modern energy systems. End-use placement of generation and storage units can mitigate network loading under suitable conditions. Within this context, DC microgrids are gaining prominence due to their suitability for local generation, storage integration, and precise power management. Motivated by these needs, this study proposes and experimentally validates a novel battery-coupled bipolar DC-DC converter that enables controlled power exchange among a DC source, a battery, and regulated bipolar outputs. The topology employs a boost stage that establishes a battery-coupled DC bus, where the duty ratio directly regulates the battery power. This is followed by an isolated stage in which phase-shift control regulates the total bipolar output voltage, while its inherent balancing characteristic maintains symmetry between the bipolar outputs. The topology enables direct connection of the energy storage unit without extra interface stages, and its natural balancing property eliminates additional sensing or balancing circuits, thereby reducing system complexity and cost.The proposed topology has been validated through simulations and experimental tests, demonstrating reliable power exchange among the ports while maintaining balanced bipolar outputs. Furthermore, the inherent balancing characteristic was verified under both symmetric and asymmetric load conditions with successful outcomes.