Transient DC bias suppression and general dynamic modulation for dual active bridge converter

This paper proposed a suppression strategy based on double equivalent superposition to solve the transient DC bias problem in dual-active-bridge (DAB) converter. Taking the triple phase-shift (TPS) as an example, the triple phase-shift values are decoupled by double equivalence, and the transient DC bias under the equivalent action of each single phase-shift angle is treated separately. Based on the phase-shift optimization scheme, a general dynamic modulation method is proposed, which makes use of the relative timing relation between gate signals and carrier to give a clear analysis of the process from transient phase-shift values to PWM (pulse-width modulation) generation. The comprehensive scheme is not affected by the specific working mode and power conditions and can reach the new steady-state in half a cycle. Simulation results verify the effectiveness of the suppression strategy.