Modeling of Dual Active Half Bridge (DAHB) converter based on discrete time techniques

The Dual-Active-Half-Bridge (DAHB) converter is being explored as a candidate for applications requiring low cost, reliable and power dense power conversion. This paper describes the discrete modelling of a DAHB converter, applicable to different modulation strategies such as Single Phase Shift (SPS), Dual-phase-shift (DPS) or Triple-Phase Shift (TPS). Discrete modelling allows a very accurate description of high frequency effects, phenomena that cannot be effectively predicted with averaged methods. This is especially useful if the half-bridge capacitance is small and the resonant frequency is comparable to the switching frequency. The modelling approach generates an accurate dynamic model, as well as a steady-state model predicting very precisely the current and voltage wave-forms, which in turn allows to make an optimal design based on numerical methods. The model has been validated with time domain simulations in both dynamic and static operation.