Small-Signal Model and Control Design Considerations for Three-Phase Dual Active Bridge Converters

This paper presents a full-order small-signal model for three-phase dual active bridge (3ph-DAB) converters for the use in electrical vehicles on-board power supply systems, connecting the HV side to LV batteries. The transfer function from phase-shift to output current is derived considering the use of different filter efforts. Employing the phasor transformation technique to formulate the small-signal model allows the identification of the inherent resonant property near the switching frequency and the one due to the input and output filters, which in turn are critical for the design of a stable control loop. Finally, Bode and Nyquist criteria are used to determine the stability of the calculated control system.