Moonem, M. A.Pechacek, C. L.Hernandez, R.Krishnaswami, Hariharan2021-04-192021-04-192015-04-20Electronics 4 (2): 239-260 (2015)https://hdl.handle.net/20.500.12588/345Dual active bridge (DAB) converters have been popular in high voltage, low and medium power DC-DC applications, as well as an intermediate high frequency link in solid state transformers. In this paper, a multilevel DAB (ML-DAB) has been proposed in which two active bridges produce two-level (2L)-5L, 5L-2L and 3L-5L voltage waveforms across the high frequency transformer. The proposed ML-DAB has the advantage of being used in high step-up/down converters, which deal with higher voltages, as compared to conventional two-level DABs. A three-level neutral point diode clamped (NPC) topology has been used in the high voltage bridge, which enables the semiconductor switches to be operated within a higher voltage range without the need for cascaded bridges or multiple two-level DAB converters. A symmetric modulation scheme, based on the least number of angular parameters rather than the duty-ratio, has been proposed for a different combination of bridge voltages. This ML-DAB is also suitable for maximum power point tracking (MPPT) control in photovoltaic applications. Steady-state analysis of the converter with symmetric phase-shift modulation is presented and verified using simulation and hardware experiments.Attribution 4.0 United Stateshttps://creativecommons.org/licenses/by/4.0/dual active bridgeDC-DC multilevel converterneutral point clamped (NPC)symmetric modulationsoft-switchingArticle2021-04-19