Fig. 1. Conceptual diagram of a LVDC system.
Fig. 2. Schematic of three-phase DAB converter.
Fig. 3. Theoretical waveforms of a three-phase DAB converter inthe forward power flow.
Fig. 4. Comparison of the RMS current and reactive powerbetween the Y-Y windings and Y-? windings.
Fig. 5. Loss comparisons between the Y-Y and Y-Δ connections.
Fig. 6. Control-to-output voltage transfer function of a three-phase DAB converter from 0 Hz to 100 kHz.
Fig. 7. Magnitude and phase Bode plots of a transfer functionaccording to output capacitance increments.
Fig. 8. Closed-loop gain with a PI controller.
Fig. 9. Closed-loop gain with a 2P1Z controller.
Fig. 10. Comparison of the output impedances using a PI and a2P1Z controller in the s-domain.
Fig. 11. Comparison of the transient performance using a PI anda 2P1Z controller in the time-domain.
Fig. 12. 5 kW prototype of the three-phase DAB converter.
Fig. 13. Experimental waveforms during steady-state operation: (a) 500 W; (b) 1.5 kW; (c) 3.5 kW; (d) 5 kW.
Fig. 14. Comparison of the controller performance: (a) PIcontroller (7A?14A); (b) 2P1Z controller (7A?14A).
Fig. 15. Bi-directional experimental waveform (3.5 kW ? -3.5 kW).
Fig. 16. Efficiency graphs of the proposed converter using a PIand a 2P1Z controller.
TABLE I DESIGN SPECIFICATIONS
TABLE II PERFORMANCE COMPARISON
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