An Interleaving 90° Three-Level DC-DC Converter and Current Sharing Control

A new topology of an interleaving three-level bidirectional DC/DC converter with voltage-loop control, which is suitable for single bus DC microgrid, was proposed in this paper. The three-level DC/DC converter can make the voltage stress of switching device half of the voltage of the high voltage terminal and common location of input and output, while the two bridges interleaving 90° can reduce the input current ripple, improve the life of the energy storage unit. The operating principle of the proposed interleaving three-level bidirectional DC/DC converter as well as the influence of the duty ratio on the operating state are analyzed in this paper to establish a state-space averaging model. Using the double loop control did not reduce the dynamic response speed of the converter, and the current loop suppresses the interphase circulation. The current sharing control for the converter is to stabilize the voltage of dc bus. Experimental results obtained from a 1kW converter prototype confirm the steady-state and the dynamic characteristics of the bidirectional energy transfer.