Accurate small-signal model for an automotive bidirectional Dual Active Bridge converter

The derivation of an accurate small-signal model for a galvanically isolated, bidirectional DC-DC converter and the implementation of a corresponding controller on a digital signal processor (DSP) as well as key methods and functions required for the digital implementation are detailed in this paper. The investigated DC-DC converter, an automotive Dual Active Bridge (DAB) system enables power transfer between a low voltage port (ranging from 11 V to 16 V) and a high voltage port (240 V to 450 V). The nominal power rating is 2 kW. The developed small-signal model yields highly accurate results for the DAB system, but the proposed modelling procedure could also be applied to arbitrary resonant power converters with unidirectional or bidirectional power transfer.