Dual-Coupled-Inductor-Based DAB DCX Converter with Full Load Range ZVS

This article proposes a dual-coupled-inductor-based dual-active-bridge dc transformer (DCX). The proposed converter utilizes the dual coupled inductor, which can integrate the leakage and magnetizing inductance together and thus reduce the required magnetic components numbers. In addition, because two coupled inductors are the same, the symmetrical structure of the converter can be obtained. Besides, the magnetic inductance can provide the possibility to achieve full load range zero voltage switch (ZVS) even with slight voltage fluctuation. Based on the integrated magnetics and considering the charging of switching junction capacitors and the magnetic inductance, the ZVS model is established under single phase shift (SPS) control. Consequently, the corresponding parameter design for achieving ZVS within the full load range of all switches under slight voltage fluctuation is introduced. Finally, the coupled inductors design considerations based on the analysis of the reluctance model, and the interleaved winding structure are discussed. Experimental results from a prototype of 250 kHz, 400/48 V, and 1000 W are provided to verify the feasibility of the proposed converter and the correctness of the theoretical analysis.