Segmental Optimal Control of Minimum Backflow Power in Bidirectional Full-bridge DC-DC Converters Based on Dual Phase-shift Control

The bi-directional full-bridge DC-DC converter has become an indispensable part of the DC microgrid due to its advantages of light weight, high power density, and bidirectional energy flow. However, the bi-directional full-bridge DC-DC converter has problems such as the backflow power and the current stress under the traditional single phase shift control, especially when the input voltage and output voltage do not match, the backflow power and current stress may increase significantly. Aiming at the mismatch between the input voltage and the output voltage, this paper proposes a minimum backflow power control strategy for the bi-directional full-bridge DC-DC converter under the double phase shift. The control strategy obtains the optimal phase shift angle of the converter under different transmission power ranges by optimizing the backflow power in sections. By comparing the proposed control strategy with the traditional dual phase-shift control, it is found that the control strategy proposed in this paper has smaller return power and current stress, and improves the performance of the converter. Finally, an experimental prototype is built based on the proposed control strategy, and the experimental results verify the correctness and effectiveness of the control strategy. © 2024 Power System Technology Press. All rights reserved.