Modular double-cascade converter

A new multilevel converter topology with cascaded H-bridges and a multi-winding medium frequency isolation transformer is introduced. The proposed converter topology has a modular structure, which is achieved using cascaded H-bridges. The isolation for the H-bridges is provided by medium frequency isolation transformers which are small compared with line frequency transformers with the same power rating. The building blocks of the proposed converter topology can be connected in series or in parallel. Series connection adds voltage steps to output voltage, and parallel connection increases the power rating of the converter.