Analysis and design of a DC to DC resonant converter for railroad applications

This paper presents the analysis and design of a series DC to DC resonant converter for railroad applications. The proposed power converter is based on IGBT modules for the AC-DC link and fast power diodes for the AC-DC conversion. The application sought is a SMPS for start-up verification of mechanical, electrical and electronic systems of train locomotives. A special feature of this converter is the use of a variable air-gap transformer in the AC link. Twelve possible operating sequences, during resonant commutation, are detailed in an analytical investigation. Experimental results are presented and commented upon.