A High Efficient DAB Converter under Heavy Load Conditions Using Inner Phase Shift Control

In heavy load conditions, the dual active bridge (DAB) bidirectional dc-dc converter transfers the power with lower efficiency due to the existence of larger circulating power flow (CPF). This paper proposes an inner phase shift (IPS) control of DAB converter to improve the efficiency under heavy load conditions by minimizing the CPF. In addition, it reduces the current stress and achieves a wide range of soft switching region. The detailed operational waveform, average power transmission analysis of DAB in the proposed IPS control has been discussed in this paper. And also, this paper presents the zero voltage switching (ZVS) characteristics and its requirements are investigated in detail. Furthermore, the operation principle of theoretical study has been validated through simulation and confirmed with the experimental demonstration.