Modelling and Control of Dual Active Bridge DC-DC Converters in DC Grids

This paper investigates the stability of cascaded Dual Active Bridge (DAB) DC/DC converters operating under a range of conditions. The multi-DAB converter’s reduced-order small signal models are formulated, and outer voltage and inner current loop controls are designed for each DAB converter. The performance of the proposed reduced-order model with the proposed control was validated via PSCAD/EMTDC simulation. These are used to predict the dynamics of the two DAB converters connected through a transmission line for different parameter values. Using sensitivity analysis, the impact of the transmission line inductance on the dynamic performance of the multi-DAB converter is investigated.