A power efficiency improvement technique for a bi-directional dual active bridge DC-DC converter at light load

Recently, the bi-directional dc-dc converter has been focused on because of the huge demand for diversification of power supply network including battery. The dual active bridge (DAB) dc-dc converter is one of the most popular circuits for bi-directional applications because of its simple structure. However, power efficiency at light load is the intrinsic problem of a bi-directional DAB DC-DC converter. In this paper, the simple solution with digital operation for the problem is proposed and experiments are performed with 1kW system. This method can reduce a switching surge without other circuits such as snubber and improve power efficiency at light load. Therefore it can reduce loss of switching surge and, improve power efficiency. From the results, 37% maximum power efficiency improvement at light load is confirmed. Furthermore, this method is capable of control in the conventional method in the heavy load range. Consequently, it is possible to reduce the switching surge and realize high power efficiency in a wide load range.

[1]  J.A. Ferreira,et al.  Concept of 50 kW DC/DC converter based on ZVS, quasi-ZCS topology and integrated thermal and electromagnetic design , 2005, 2005 European Conference on Power Electronics and Applications.

[2]  D.M. Divan,et al.  A three-phase soft-switched high power density DC/DC converter for high power applications , 1988, Conference Record of the 1988 IEEE Industry Applications Society Annual Meeting.

[3]  Yoichi Ishizuka,et al.  A Power Efficiency Improvement Technique for a Bidirectional Dual Active Bridge DC–DC Converter at Light Load , 2014, IEEE Transactions on Industry Applications.

[4]  D.M. Divan,et al.  Performance characterization of a high power dual active bridge DC/DC converter , 1990, Conference Record of the 1990 IEEE Industry Applications Society Annual Meeting.

[5]  Tamotsu Ninomiya,et al.  Switching surge reduction of a bi-directional dual active bridge DC-DC converter with a digital operation , 2013, 2013 15th European Conference on Power Electronics and Applications (EPE).

[6]  Ishizuka Yoichi,et al.  A static characteristic analysis and high power efficient technique of the light load condition of Bi-Directional Dual Active Bridge DC-DC Converter , 2013 .

[7]  Hirofumi Matsuo,et al.  An ac-link bidirectional DC-DC converter with synchronous rectifier , 2010, IECON 2010 - 36th Annual Conference on IEEE Industrial Electronics Society.

[8]  Nikolaus Schibli.  Symmetrical multilevel converters with two quadrant DC-DC feeding , 2000 .

[9]  H. Akagi,et al.  A Bidirectional Isolated DC–DC Converter as a Core Circuit of the Next-Generation Medium-Voltage Power Conversion System , 2007, IEEE Transactions on Power Electronics.

[10]  T. Ninomiya,et al.  A unified analysis of resonant converters , 1991 .