Energy Reports (Sep 2023)
Proposed asymmetric phase shift modulation strategy to improve zero-voltage-switch range and transmission power range for dual active bridge converter
Abstract
The dual active bridge (DAB) DC–DC converter is typical in DC transformers to realize the voltage transformation and power transmission, which is determined by modulation. However, in traditional phase shift modulation strategies, the zero-voltage-switch (ZVS) range and the transmission power range of DAB are limited, and the current bias exists in light load. Therefore, a proposed asymmetric phase shift modulation strategy (PAPSM) to realize full ZVS range, larger transmission power, and non-DC bias in high frequency link (HFL) for DAB is introduced in this paper. In PAPSM, the modulation signals in adjacent periods are symmetric and in the opposite direction, and the current characteristics in the adjacent periods are still consistent. Thus, the equivalent period of DAB in PAPSM is expended, and the current bias accumulation in light load is eliminated in the equivalent period, without any extra operation. Then, the operating principles of DAB in PAPSM are introduced, to analyze the ZVS range, power delivery range, and maximum transmission power in detail. Compared with traditional phase shift modulation strategies, PAPSM can realize full ZVS range, wider power delivery range, and larger maximum transmission power by adjusting an outer phase shift ratio and an asymmetric duty ratio, and the DC bias in HFL can be eliminated. Finally, a DAB experimental setup is established based on RT-LAB, proving the theoretical analysis.
