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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. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive optimization control scheme to improve efficiency and dynamic response of dual-active-bridge (DAB) dc–dc converters. Unified-phase-shift (UPS) control is widely used to increase the efficiency of DAB dc–dc converters by minimizing the peak current, but dynamic performance of the converters needs to be further enhanced. In this paper, to gain superior dynamic performance of DAB dc–dc converters, an equivalent power-balancing (PB) model is employed, which is capable of predicting dynamic behavior of converter output voltages due to input voltage fluctuation and load disturbance. And then, combining the UPS control and the PB control, a comprehensive UPS and PB (UPS-PB) scheme is proposed to improve the efficiency and dynamic performance simultaneously. This work also includes the detailed inductance parameter sensitivity of the proposed UPS-PB scheme and a zonal voltage control strategy to further improve dynamic responses of the output voltage under the start-up process or a large step change of the output voltage reference. Moreover, the variant of UPS-PB scheme for constant power load is analyzed in the experimental part. Finally, experimental results have verified the excellent performance of the proposed UPS-PB scheme and correctness of theoretical analysis in this work. [ABSTRACT FROM AUTHOR]

High dynamic performance is an essential requirement for the dual-active-bridge (DAB) dc/dc converters. As dc voltage sources, they should maintain the desired output voltage instantly under all working conditions. However, the previous literature mainly focus on the dynamic control of the voltage-fed DAB converters, and the existing control schemes for the current-fed DAB converters achieve limited dynamic performance. Aiming at improving the dynamic performance, a direct actual-power control (DAPC) scheme based on virtual impedance estimation (VIE) is proposed for the current-fed DAB converters in this article. The proposed DAPC scheme is based on a parallel structure instead of the series structure of existing control schemes, and it realizes fast dynamic control through combining actual power control with the VIE method. The proposed DAPC scheme can obtain the fastest transient response for the output voltage without voltage overshoot in transient conditions, such as load step change, input voltage fluctuation, and the desired output voltage step change. Besides, a leakage inductor precharging method is integrated into the DAPC scheme to avoid the current mismatching. Finally, the proposed DAPC schemes are compared with two existing control schemes and tested in a scale-down experimental prototype. Experimental results verify the effectiveness of the proposed DAPC scheme. [ABSTRACT FROM AUTHOR]