Research On Multi-Winding-Coupled-Inductor-Based Dual Active Bridge DC-DC Converter

In the all-electric combat vehicle power supply system,as a bridge connecting high voltage bus and low voltage equipment or energy storage device,the dual active bridge DC-DC converter has the advantages of symmetrical circuit structure and easy to realize soft-switching.However,in the application of wide voltage range,the number of magnetic components of current-fed dual active bridge DC-DC converter is large,resulting in low power density of the system.In order to solve this problem,this paper proposes a multi-winding-coupled-inductor-based dual active bridge DC-DC converter topology.And the specific innovative work includes:(1)In order to solve the problems of large number of magnetic elements,large volume ratio and low power density in the current-fed dual active bridge DC-DC converter,a multi-winding-coupled-inductor-based dual active bridge DC-DC converter topology is proposed in this paper.The number of magnetic components can be significantly reduced and the power density of the converter can be increased by using multi-windingcoupled-inductor to integrate magnetic components.At the same time,the proposed magnetic integrated circuit topology has the advantages of small input current ripple,wide fload range soft-switching and wide voltage range.(2)Aiming at the proposed converter topology,an analysis method of multi-winding-coupled-inductor integrated magnetic components is proposed in this paper,furthermore,the modes,poer thransport character and the condition of soft-switching are analysied in detail.Based on the magnetic reluctance model of multi-winding-coupled-inductor and combined with working modes analysis,the proposed analysis method can clearly show the relationship between the current,voltage and magnetic flux inside the magnetic parts,and greatly simplify the magnetic circuit analysis.And it is of great significance to the characteristics analysis and parameter optimization design of soft-switching.(3)On the premise of meeting the soft-switching conditions of switches,taking the minimum inductance RMS current as the optimized objective,the optimization design process of inductance parameters is improved in this paper.It not only realizes the full range of soft switching but also significantly reduces the inductance RMS current and improves the efficiency of the converter.Finally,an experimental prototype of multi-winding-coupledinductor-based dual active bridge DC-DC converter with rated 18-36 V input and 360V/1000 W output was designed.The experimental results show that all the switches can realize wide voltage range ZVS.The proposed magnetic intergrated converter significantly improves the operating efficiency and power density.