Transient DC Bias Suppression with Rapid Power Reversing for EPS Whole Voltage Range in Dual Active Bridge DC-DC Converter

During typical dynamic operations of a dual-active bridge (DAB) converter, such as start-up and power changes, a transient DC bias may emerge, potentially causing harm to its components, power supply facilities, and connected electrical loads. Traditionally, transient optimizations have mainly focused on unidirectional analysis, ignoring the inherent bidirectional power transmission and zero voltage switching (ZVS) capability of the DAB converter. This work proposes a novel DC bias suppression strategy based on a straightforward phase-shift optimization method for rapid power reversal, which is valid for achieving transient ZVS with a wide load range in the DAB converter. Conventional control schemes rely on the single-phase-shift (SPS) modulation method to reduce DC variation while ignoring the limitations of SPS control strategies, such as excessive backflow and a limited zero-voltage-switch range. Comprehensive experimental results indicate that DC deviation generated during the transient power reverse stage can be well eliminated with all switches achieving ZVS in all load conditions without any added snubbers.