Reactive current optmisation for high power dual active bridge DC/DC converter

This paper presents a new approach for minimizing reactive power for the dual active bridge DC/DC converter for high power applications. The chosen topology comprises of two active bridges with internal medium frequency transformer. Assuming the converter operate in steady-state, both bridges are analyzed with an AC equivalent circuit where only the fundamental component of the voltages and currents are considered. The phase shift angle between the two AC voltages can manipulate the power flow of the converter and the phase shift on the individual bridge branches control the AC voltage magnitude are realized in the steady-state analysis. It is possible to achieve zero reactive power based on the control strategies and proper selection of the transformer parameters. The transformer design steps based on zero reactive power conditions are also provided. Finally, a 3 MW 4/40 kV dual active bridge DC/DC converter is modeled in SABER platform to confirm the converter performance from the theoretical analysis.