| Abstract |
In this paper a two-stage bidirectional Power Factor Correction (PFC) boost-buck topology featuring a novel built-in energy storage buffer functionality is proposed, specifically tailored for (isolated) OBC applications.Main concept idea is to allow a certain amount of voltage oscillation at twice the line frequency at the output of the boost PFC stage (allowing a significant reduction of the dc-bus capacitor), and let the cascaded step down converter, namely the SCB-PPB, to dynamically absorb the pulsating energy, aiming at supplying a stiff voltage for the multi-port DCX stage feeding the battery.The topology incorporates modular single-phase TP modules that deliver 3.6kW each in a three-phase set-up, or can be configured in parallel for single-phase operation at 2.4kW each, resulting in total output powers of 11kW and 7.2kW, respectively.The proposed active buffer solution allows enhancing the power density of the system, by minimizing the capacitor size, and makes use of varied semiconductor devices with breakdown voltages of 750V and 1.2kV.A MOO process is adopted to seek for the most effective balance between bulk capacitance and inductive components against losses and switching frequencies, thus achieving peak power density.Comprehensive analytical and simulation results are shown to validate the effectiveness of the proposal, together with a sketch of the actual experimental prototype. |
