Characterization of Cycling Current in Pumpback Test for Loss Assessment of DAB Converter

Dual active bridge (DAB) converter using SiC devices can transfer power of tens to hundreds of kilowatts. To evaluate the performance and loss of the converter, pumpback is used under laboratory conditions, where capacity of distribution box is limited. In this paper, the mechanism of the pumpback line current fluctuation is analyzed for the first time. A simplified circuit model is established, which reveals that the line inductance is the major influence factor of the fluctuation. Finally, this paper gives some advice on the choice of the line inductance value. A 100 kW DAB converter is established. Simulation and experiment results prove the validity of the analysis.