Novel asymmetric duty modulation for DAB converters to improve light load efficiency

In a DC distribution network, the solid-state transformer (SST) and energy storage systems require an isolated bidirectional DC–DC converter (IBDC). Among the many IBDCs, the dual active bridge (DAB) converter has been widely studied due to its advantages in terms of high power density and high efficiency. The traditional control strategy for DAB is phase shift control. However, when the primary and secondary side voltages do not match, the soft-switching characteristic and increasing current in the phase shift control affect the application of DAB in scenarios involving input and output voltage changes. To improve the above-mentioned defects, a novel asymmetric duty modulation (ADM) control is proposed in this paper. Among the various multi-variable ADM controls, the two-variable ADM control is simple, but its current is higher under light loads. To improve this defect, this paper introduces trapezoidal modulation (TZM) control proposed for phase shift control into ADM to form a similar TZM (STZM) control corresponding to TZM control. This paper first expounds the basic principle of STZM control. On this basis, its basic characteristics are researched. With current stress as the optimization goal, an optimal STZM (OSTZM) control scheme with minimum current stress is proposed, and the effectiveness of the theoretical analysis is verified on the experimental bench. The result shows that STZM control can improve efficiency under light loads by reducing the current and ensuring full ZVS.

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Cite this article

[IEEE Style]

F. Wang, X. Cui, F. Zhuo, J. Tian, Z. Zheng, R. Xu, "Novel asymmetric duty modulation for DAB converters to improve light load efficiency," Journal of Power Electronics, vol. 23, no. 4, pp. 592-606, 2023. DOI: 10.1007/s43236-022-00565-0.

[ACM Style]

Feng Wang, Xinyu Cui, Fang Zhuo, Jiachen Tian, Zhi Zheng, and Ruixin Xu. 2023. Novel asymmetric duty modulation for DAB converters to improve light load efficiency. Journal of Power Electronics, 23, 4, (2023), 592-606. DOI: 10.1007/s43236-022-00565-0.