This paper presents the findings of a R&D project connected to the development of 50 kW auxiliary power supply for the high-voltage DC-fed commuter trains. The aim was to design a new-generation power converter utilizing high-voltage IGBT modules. which can outpace the predecessor (6. 5 kV IGBT based twolevel half-bridge DC/DC converter) in terms of power density. https://www.roneverhart.com/Persol-3195-S-58mm/