Comparative Analysis of Unidirectional High Step-Up Converters for Medium-Voltage Applications

Abstract:
Connection of renewable energy sources to the MVDC collection grid requires an efficient, reliable and economically viable high power DC/DC converter. With these requirements in mind, the paper presents a comparative analysis of two bulk-power processing converter topologies - the Single Active Bridge (SAB) and the Phase Shifted Full Bridge (PSFB) converter from the standpoint of suitability for the application, considering power hardware design and control requirements. The aim of the work is to provide a clear summary of trade-offs between the SAB and PSFB converter without their detailed design optimization. An overview of the converters’ operating principles and steady-state models is presented first, laying the foundation for the comparison through converter characteristics. Based on carefully chosen exemplary designs the advantages and drawbacks of both topologies are identified and preliminary semiconductor losses are evaluated for each case. Finally, the input voltage regulation of the converters is addressed as well as additional considerations relevant for the applications of interest.