Closed-Loop Black Start-Up of Dual-Active-Bridge Converter With Boosted Dynamics and Soft-Switching Operation

This letter proposes a closed-loop black start-up control for the dual-active-bridge (DAB) converter. With a simple combination of the extended phase-shift and triple phase-shift modulation schemes, the DAB converter can start up with the maximum allowable precharge current while realizing soft-switching operation in the trapezoidal current mode simultaneously. Compared to the conventional start-up procedure that usually requires multiple steps of operation and parameter fine-tuning, the proposed start-up method can be implemented simply into the existing closed-loop controller and can shorten the start-up transients of the DAB converter significantly. The presented methods are validated experimentally on a downscaled DAB converter prototype.