Modeling and Analysis of a Dual-Active-Bridge-Isolated Bidirectional DC/DC Converter to Minimize RMS Current With Whole Operating Range

• Published in: IEEE transactions on power electronics Vol. 33; no. 6; pp. 5302 - 5316
• Main Authors: Tong, Anping, Hang, Lijun, Li, Guojie, Jiang, Xiuchen, Gao, Shenyu
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.06.2018; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Analytical models; Bridge circuits; Computational modeling; Dual-active-bridge-isolated bidirectional dc/dc converter; Electric bridges; Electric converters; Exact solutions; Feasibility studies; Inductors; Mathematical model; Mathematical models; minimum current operation; Modulation; optimal modulation scheme; Phase modulation; triple phase shift (TPS); Voltage converters (DC to DC); zero current switching
• ISSN: 0885-8993; 1941-0107
• DOI: 10.1109/TPEL.2017.2692276

The triple phase shift (TPS) modulation scheme, which provides three control freedoms, is of great importance for the optimized operation of a dual active bridge (DAB) isolated bidirectional dc/dc converter. First of all, this paper introduces an accurate, universal model to describe the analytic expressions of the DAB converter under TPS control. Based on this, six operating modes of the DAB converter are further discussed. Afterwards, the concept of global optimal condition (GOC) equations is proposed to derive the closed form of analytic expressions of an optimal modulation scheme that makes the DAB converter operate with minimized root-mean-square (rms) current during whole power range with different operating modes. According to the GOC equations, the physical explanation of the proposed modulation scheme is further given in details, and the complex interaction among the control variables, the transferred power, and rms current is revealed. The real-time optimization process of the proposed method is also specified. Finally, the proposed methods are applied to a laboratory prototype. The experimental results confirm the theoretical analysis and practical feasibility of the proposed strategies.