Design Methodology for Bidirectional Resonant Converter With Dual Resonant Frequencies for Wide Voltage Range

This article presents the design methodology for a bidirectional
CLLC
resonant converter with dual resonant frequencies for charging a wide range of battery voltages. The proposed design method improves the battery-charging voltage range by operating at two resonant frequencies with constant current and constant voltage regardless of load variations. Furthermore, the proposed design method improves the conversion efficiency and simplifies the controller because it operates at fixed resonant frequencies. To validate the proposed design method, a 3.6-kW experimental prototype is configured. Experimental results show that compared with the conventional method, the proposed design method improves the efficiency by approximately 3.13% under light load conditions, and the measured maximum efficiency in the charging and discharging modes is 98.04% and 98.05%, respectively.