Comparison of LLC-DAB DC-DC Converters with Partial Power Capability for EV Powertrains

In this paper two Dual Active Bridge (DAB) based DC-DC interfaces with Partial Power Converter (PPC) capability are evaluated and compared in terms of overall system efficiency. The power topology structure analyzed in this work is specifically designed for the energy management of high-power density in Electric Vehicle (EV) powertrains. The implementation of a LLC-DAB (Inductor-Inductor-Capacitor DAB) converter gives the possibility of improved operation at zero DC-bias in the High Frequency Transformer (HFT) compared with conventional DAB. In fact, this paper lies in the combination of this LLC-DAB topology with a PPC input-parallel output-series (IPOS) connection. The LLC-DAB and PPC LLC-DAB topologies operation are commanded under two modulation schemes with simulation results. By summary, the overall peak efficiency is achieved with the PPC LLC-DAB at 97.75% with the dual phase-shifted modulation (DPS).