Pre-design methodology and results of a robust monolithic Inter Cell Transformer (ICT) for parallel multicell converter

In this paper, the pre-design methodology of a monolithic Inter Cell Transformer (ICT) in parallel multicell converters is presented for normal operation and with a reduced number of phases. The goal is not to saturate the active phases when the number of cells is reduced. An analysis and comparison of monolithic ICT have been conducted in these two configurations. The increased volume and mass of the robust monolithic ICT is very important for low number of cells. Air-gaps have been inserted in order to limit this augmentation. These air-gaps balance and reduce the overload flux density in active cores during the post-failure operation. In order to validate the theoretical results, a ladder structure of a 6-phase monolithic ICT and a reconfigurable converter has been built. The experimental results for the prototype will be presented by the authors in their next paper.