Efficiency optimization modulation strategy for dual active bridge converters at light loads considering IGBT dynamic charge characteristics

Dual active bridge (DAB) converters play a crucial role in bidirectional DC-DC systems, making efficiency optimization strategies particularly important. In high-power applications, insulated gate bipolar transistors (IGBT) are commonly used as switching devices. The turn-off losses in IGBTs are primarily determined by the charge accumulation in the N-base region during switching. This paper analyzes the dynamic charge behavior within IGBTs and introduces a current correction modulation strategy (MCSM) based on triangular wave modulation, specifically designed for light load conditions. By reshaping the inductor current in the DAB converter, this method increases the time available for charge recombination within the IGBT, effectively reducing the turn off losses. The effectiveness of the proposed optimization modulation method is experimentally validated with a 4 kW DAB converter. Experimental results reveal that the converter achieves up to 90% efficiency at load power levels ranging from 5 to 42%. Compared to the zero current switching (ZCS), the zero voltage switching (ZVS) technique, and traditional single phase shift modulation, the proposed method improves efficiency by 8.42%, 11.67%, and 29.55%, respectively. Overall, this approach significantly reduces the turn off losses in the primary-side switches of the DAB converter.

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Cite this article

[IEEE Style]

X. Liu, X. Guo, L. Xu, Y. Li, K. Li, X. Hao, "Efficiency optimization modulation strategy for dual active bridge converters at light loads considering IGBT dynamic charge characteristics," Journal of Power Electronics, vol. 26, no. 2, pp. 305-315, 2026. DOI: 10.1007/s43236-025-01071-9.

[ACM Style]

Xuan Liu, Xizheng Guo, Lei Xu, Yue Li, Kai Li, and Xin Hao. 2026. Efficiency optimization modulation strategy for dual active bridge converters at light loads considering IGBT dynamic charge characteristics. Journal of Power Electronics, 26, 2, (2026), 305-315. DOI: 10.1007/s43236-025-01071-9.