An Isolated Three-Port DC-DC Converter with a Current-Fed Half-Bridge Port for Battery Energy Storage System

Battery energy storage is widely used in renewable energy systems because of its mature technology and ability to provide sufficient energy and power density. Connecting the dc microgrid and the battery through a voltage-fed dc-dc converter will produce large current ripples, which will affect the performance and life of the battery. In this article, an isolated three-port dc-dc converter with a current-fed half-bridge port is proposed. The dual inductors of the current-fed half-bridge are directly connected to the battery, the current ripple can be reduced without the need for an additional LC filter on the energy storage side, and the high voltage gain can flexibly adapt to a wide range of battery voltages. Then the operating principle of the topology in the two modes of battery charging and discharging is analyzed, and the operating boundary conditions of the two modes are introduced. Finally, the performance of the topology was verified through simulation and experiments, and the prototype efficiency was measured.