Controller Design of a DAB Converter for Battery Charging and Discharging Applications

Recently, as the demand for DC systems has rapidly increased, research on battery chargers has been conducted extensively. Among DC/DC converters, the DAB converter has the advantage of enabling ZVS(Zero Voltage Switching) operation and securing bidirectional power transmission and insulation by using a transformer in a left-right symmetrical structure. Since bidirectional operation is possible, it is widely used in DC grid systems and battery chargers. This paper proposes a switching method that integrates three switching methods, TPS, EPS, and SPS, for efficient converter operation in a wide load range. In addition, a controller that smoothly operates CC-CV (Constant Current–Constant Voltage) mode conversion and has self-protection operation is proposed, and the operating characteristics are verified through simulation and experiments using the fabricated DAB converter.