Bidirectional Multiple-Port Three-Level DC-DC Converter for HESS in DC Microgrids

Abstract

This paper proposes a bidirectional multiple-port three-level (BMPTL) DC-DC converter with two-stage structure for the hybrid energy storage system (HESS). The advantages of the proposed converter over the conventional converters for HESSs including reduced component size, superior extension capability and better control flexibility. These advantages results from the two-stage structure, the availability of three voltage levels, and the multiple-port design. A new control method based on deadbeat control strategy has been developed to regulate the BMPTL DC-DC converter. The proposed deadbeat-based method can mitigate the power imbalanced in DC microgrid and allocate proper power assignment for the battery and supercapacitor according to their characteristics simultaneously. To conduct the verification, a DC microgrid simulation model including the PV, load and HESS interfaced by the proposed BMPTL DC-DC converter is built. The simulation results are discussed in detail to demonstrate the effectiveness of the proposed BMPTL DC-DC converter with the deadbeat-based method.