Design, Analysis and Performance Characterization of Dual-Active-Bridge DC-DC Converter Utilizing Three-Phase Resonant Immittance Network

This paper proposes a three-phase dual-active-bridge (3p-DAB) dc-dc converter that utilizes three-phase resonant immittance network (3p-RIN) to achieve the unity power factor operation. The proposed 3p-RIN maintains the unity power factor operation at both ac links of the 3p-DAB over full range of operation; thus, mitigating the reactive power loss. It can perform the full ZVS operation as well for diminishing the switching losses. For the unity power factor operation, the converter operates in in-phase mode between primary and secondary side voltages, whereas for the full ZVS operation, the converter operates in lagging phase relationship between the primary and secondary side voltages, respectively. The power flow through the converter is controlled by modulating either internal (for unity power factor operation) or both internal and external phase-shift angles (for full ZVS operation); thus, providing two degrees of freedom. A detailed evaluation of the converter is performed using the fundamental component analysis for voltages and currents of 3p-RIN. The theoretical analysis is supported by the experimental results obtained from a 400-V/220-V, 2-kW prototype operated at both unity power factor and full ZVS operating modes. The unity power factor operation gives better performance as compared to the full ZVS operation for the selected specifications of the converter.