In this paper, a universal power flow model for the Dual Active Bridge (DAB) based dc-dc converters with phase-shift modulation is derived. The model considers the lossy components, the dead time, and the resonant commutations of the converters. A power flow model for the Partial Parallel Dual Active Bridge (P2DAB) converter is generated from the universal power flow model. Based on the calculations, the power plateau phenomenon and the anti-power phenomenon, as well as their causes and influences are discussed. Because of the zero-reactivepower-loss in the lagging full-bridge, the zero-voltage-turn-on of all of the switches, and the zero-current-commutation of the switches in the lagging full-bridge during the power plateau, a hypothesis, which claims that the converter is more efficient in the power plateau operation than in other operation modes, is made. A laboratory prototype of the P2DAB converter is constructed. The analysis about the power plateau and the antipower phenomenon is verified, as well as the proposed hypothesis is proved. Compared against the measured power, the model for the (P2DAB) converter has the maximum error less than 10%. Therefore, the validity of the universal power flow model is verified.
- Bidirectional dc-dc converter
- Dual active bridge
- Phase-shift modulation
- Power flow model