Comparative Evaluation of Isolated Bidirectional DC/DC Converter in High-Power High-Frequency Occasions

The Isolated Bi-directional DC/DC Converter (IBDC) is a key equipment in Solid State Transformer (SST) and Electric Energy Router (EER) for power distribution networks. Topologies namely DAB, LLC and CLLC are chosen as candidates because of their DC voltage regulate capability, bi-directional power transmission capability, and soft switching characteristics to achieve high efficiency. In this paper, these topologies are compared in high-power high-frequency occasions comprehensively. Their topology models and control methods are investigated. Based on a 30kW, 20kHz IBDC module, their design procedures are carried out to achieve best soft switching characteristics. Their main transmission characteristics and loss characteristics are evaluated and compared using design results. Moreover, this paper clarifies advantages and drawbacks of these topologies. Resonant topology holds advantage of soft switching feature and ease of control. Topology selection advice is given at last.