Ripple current control for single phase-shift dual active bridge converters

Nowadays, the need for isolated bidirectional DC/DC converters is growing. In these types of equipment, the dual active bridge topology is widespread, where mostly the transformer leakage inductance value determines its dynamic behavior. Voltage imbalance between the primary and secondary side results in unwanted excessive transformer peak current if the leakage inductance is low, thus limiting the load transient response of the converter. In this paper, a ripple current control method is presented, which reduces the transformer peak current to its minimal level, furthermore, allows the magnetizing current components to be distributed between the primary and secondary sides in an arbitrary proportion. The proposed control was tested in HIL simulation and on a real 360kW dual active bridge converter. Based on the results the current stress on semiconductors and DC capacitors were reduced while the utilization and the efficiency of the converter were increased. Key words: Dual active bridge, ripple current, single phase-shift, converter