Theoretical and experimental analysis of the soft switching process for SiC MOSFETs based Dual Active Bridge converters

In the new electrical grids, series/parallel converters architectures can be considered for medium and high voltage power conversion. Dual Active Bridge (DAB) topology is a serious candidate to be implemented within these converters. In order to increase the power density, the trend is to operate with a higher switching frequency. Thanks to Zero Voltage Switching (ZVS) operation, DAB topology allows the switching losses to be reduced. Theoretically, the ZVS operation range depends only on the operating range of the converter. In reality, since the parasitic elements are involved in the soft switching process, the ZVS operation range may be modified. In this paper, the authors propose an analysis of the soft switching process for the case of a SiC MOSFET based DAB converter. This study is based on analytical analysis and experimental results obtained with a 1.2 kV - 100 kW DC-DC converter prototype.