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

Abstract

Abstract-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.

A static characteristic analysis of proposed bi-directional dual active bridge DC-DC converter

“…However, the problem of switching surges reduction was not addressed. In [13], the novel switching surge reduction technique is proposed and confirmed with some analysis and experimental results. And also, the results of power efficiency improvement of the light load were described.…”

“…The detailed description of the ideal circuit is revealed in a previous paper [13]. Therefore, only the results are shown in this paper.…”

“…It can be reduce the switching surges at the light load, without any of additional circuits such as the snubber circuits or resonant circuits [13]. Fig.…”

Static Characteristic Analysis of Proposed Bi-Directional Dual Active Bridge DC-DC Converter

“…The detailed description of the ideal circuit is revealed in previous papers (15) (16) . Therefore, only the results are shown in this paper.…”

“…We have proposed the software-based compensation method for a basic DAB dc-dc converter topology (15) (16) . It can reduce the switching surges for a light load, without any of additional circuits such as the snubber circuits or resonant circuits.…”