Abstract

The multilevel dual-active-bridge (ML-DAB) is a cutting-edge converter configuration designed to enhance the performance of dc–dc conversion, particularly in the medium-voltage electric vehicle (EV) charging applications. ML-DAB offers improved voltage blocking and power range capability compared with traditional DAB converters. In this article, a switch-control scheme for a T-type neutral-point-clamped (TNPC) DAB dc–dc converter is presented. The key novelty of the proposed modulation scheme is the reconfigurable operation of the TNPC-based DAB converter among six different power configurations without the need to modify the implementation scheme. In fact, by only changing two modulation angles, two-to-five levels can be generated. The contribution of this article is the implementation of a switch control and state machine scheme that allows working on a reconfigurable ML-DAB topology with different improved figure-of-merit (FOM) performances. The evaluation of the maximum combined efficiency curve highlights that the half-bridge, DAB, and proposed ML-DAB configurations exhibit better efficiencies at low-, medium-, and high-power ranges, respectively. Experimental tests under a scaled-down power prototype to verify the proposed modulation method and control scheme implementation are performed. © 2013 IEEE.