Soft-Switching Isolated Dual Active Bridge Bidirectional DC-DC Converter with Simple Structure

In this paper, a soft-switching isolated dual active bridge bidirectional DC-DC converter is proposed. Bidirectional DC-DC converters have many applications for electrical energy storage systems. Dual active bridge structures are the basic structure of this application due to their higher power density and efficiency. But the leakage inductance of this converter leads to increased conduction and switching losses and reduces efficiency. Some techniques such as active snubber, active clamp and resonant circuits are applied to achieve soft-switching conditions for the converter in recent researches. However, additional elements and variable frequency are the main disadvantages of these techniques. In the presented converter, the soft-switching conditions is provided by use of phase shift control with no auxiliary switch or circuit. The switching frequency and resonance frequency are equal in this converter which results in simplicity of control circuit. In this survey, the proposed converter and operating modes are illustrated and experimental results are reported to demonstrate theoretical analysis.