Design of high-performance bidirectional DC/DC converter applied for more electric aircraft

Bidirectional DC/DC converter is an important part of the more electric aircraft (MEA). A high-performance bidirectional DC/DC converter with high efficiency and power density reduces the both volume and power loss of the converter. There are mainly two kinds of basic topologies applied to bidirectional DC/DC converter. One is a dual active bridge (DAB) and the other is symmetrical CLLC resonant topology. Both topologies can realise zero-voltage switch (ZVS). The DAB has been widely researched and applied to many fields including the MEA as DAB is easy to design and control. However the ZVS region of the DAB is limited. What is worse, the DAB always switches when the current is at the peak. Symmetrical CLLC resonant topology has also been widely researched in recent years. Compared with the DAB, the symmetrical CLLC resonant converter can reach ZVS in a wider region. In this study both the topologies are discussed and the design of the better one is demonstrated. A 3 kW symmetrical CLLC resonant converter is designed to verify the conclusion.