A Comprehensive Comparison of Two Fast-Dynamic Control Structures for the DAB DC-DC Converter

Benefitting from some significant advantages, the dual active bridge (DAB) dc-dc converter has become one of the most promising candidates for dc-dc power conversion. In recent years, some strategies have been proposed to boost the dynamic performance of DAB dc-dc converter under the disturbance of input voltage and load condition. According to the relationship between the compensation part and the model-based part, these existing schemes can be divided into two structures including the parallel structure and series structure. In the parallel control structure, the compensation part is added to the model-based part. In contrast, the compensation part is multiplied with the model-based part in the series control structure. By adopting proper feedback control, both control structures can provide excellent dynamic performance for DAB dc-dc converter easily. Hence, the modified parallel-structure fast-dynamic control scheme and the modified series-structure fast-dynamic control scheme are both proposed in this article. Then, using these two proposed schemes as examples, the merits and the demerits of both structures are analyzed, and the corresponding compensation methods are also presented. Moreover, a general PI design principle of the model-based control scheme for the DAB dc-dc converter is provided, which is different from the traditional concept for designing the PI parameters. In addition, the control delay of these two proposed schemes is analyzed, and a compensation method is also proposed. Finally, simulation results and experimental results are obtained to verify the analysis in this article and the excellent performance of the proposed methods.

Automated summary

The dual active bridge (DAB) dc-dc converter has emerged as a promising candidate for dc-dc power conversion due to its advantages. However, the dynamic performance of the converter can be affected by input voltage and load disturbances. This article proposes modified parallel-structure and series-structure fast-dynamic control schemes to enhance the dynamic performance. The merits, demerits, and compensation methods of both structures are analyzed. Additionally, a general PI design principle for the model-based control scheme is provided, along with an analysis of control delay and a proposed compensation method. Simulation and experimental results demonstrate the effectiveness of the proposed methods.