Flexible Power-Sharing Control Strategy for Triple-Active-Bridge DC–DC Converter With Fast-Dynamic Response

Abstract

Triple-active-bridge (TAB) dc-dc converter is a good candidate for multiple applications such as renewable energy, electric, and fuel cell vehicles due to its capability of integrating different sources and loads into a single system. Furthermore, it is essential to have a robust control strategy to obtain better dynamic performance for this converter. However, the realization of a fast-dynamic response using the traditional control approaches of the TAB dc-dc converter is hard due to the coupling among the three inductances of each port. Thus, modulation calculation and the model-based control design become very difficult. As a solution, the TAB dc-dc converter can be modified to a three-port dual-active-bridge (DAB) dc-dc converter, and the power coupling among the ports can be significantly reduced. Then, this article proposes a flexible power-sharing control strategy for the TAB dc-dc converter based on the combination of model-based feedforward compensation and output voltage feedback control strategy. Moreover, the stability analysis of the proposed control strategy is presented to verify the robustness of the control scheme in different conditions. In addition, the design principle of the PI parameters is provided for this converter. Finally, the effectiveness of the proposed control strategy and the accuracy of the PI parameters design are validated using simulation results and experimental results obtained from a small-scale hardware prototype.