To address the inability of conventional dual active bridge (DAB) converters to simultaneously achieve zero backflow power and global soft switching under wide input voltage variations

an improved triple-phase-shift (ITPS) modulation strategy for LCL-T resonant DAB converters is proposed. First

the power transfer characteristics and soft-switching behaviors of the LCL-T resonant DAB converter are analyzed

deriving the control variable expressions for achieving zero backflow power under different voltage conversion ratios. Subsequently

by leveraging the symmetry of the LCL resonant network and incorporating ZVS constraints considering switching device parasitic capacitances

unified ITPS modulation control expressions are derived that are continuous over the entire operating range

have a uniform form

and require low computational effort

with the modulation trajectories further optimized. Finally

a 1 kW experimental prototype validates the effectiveness of the proposed modulation strategy. Experimental results demonstrate that the ITPS modulation strategy achieves a wider input voltage range

zero backflow power

and global soft-switching capability

compared to conventional modulation strategies.