Research on Optimal Design of Bidirectional Converter Based on Multiplexing of DAB and CLLC

In this paper, an optimal design scheme of a bidirectional power converter is proposed by multiplexing the switch bridges of the DAB and CLLC converters. The proposed scheme operates the converter at a fixed switching frequency, adjusting the output voltage only through phase-shift control. The proposed multiplexing structure leverages the respective advantages of DAB and CLLC. The CLLC part benefits from its higher conversion efficiency and thus undertakes more power conversion, while the DAB part is responsible for the overall gain regulation of the converter due to its wide gain regulation range. This enables the proposed bidirectional power conversion scheme to maintain high conversion efficiency while satisfying a wide range of gain regulation. In addition, the full-range zero-voltage turn-on of all switches and the zero-current turn-off of synchronous rectification switches can be realized through bridge multiplexing and parameter optimization design. To verify the validity of the proposed scheme, this paper analyzes the operation principle and soft switching characteristics of the proposed converter in detail, and builds an experimental prototype with 200 V input, 40−56 V output (40−56 V input, 200 V output when working in reverse), and a rated power of 120 W.