A Comprehensive Modulation Scheme of DAB with Variable Voltage Gain

Dual active Bridge (DAB) converter has features as zero voltage switching (ZVS), high frequency isolation and symmetrical bridge operation in both power direction. In this paper, a practical triple-phase-shift (TPS) modulation with only one `root' control degree is proposed to optimize the inductor current which also flows though power switching devices. All switching devices on the high voltage side can realize ZVS, while only one bridge leg on the low voltage side can't realize ZVS under the condition of light load, though the low switching current of this leg could bear low switching loss. This modulation scheme can reduce DAB loss when the variable voltage gain is not equal to 1. Experiment has been carried out to verify the modulation scheme.