Comparison of Selected Megawatt-Level Traction Converter Power Module Implementations in terms of Commutation Inductance and Practicality

Abstract:
Rail vehicles utilize traction converter in high-, mid-, and low-power segments. The high power segment converters with above 1 MW are mainly utilized in locomotives and high speed EMUs. For these converters; semiconductors, capacitors and busbars are critical regarding power capability, electrical performance, reliability as well as practicality (ease of production, maintenance and testing). This study focuses on a 1250 kW locomotive traction converter with two-level circuit employing 3.3 kV IGBT modules in conventional package. In this paper, the converter circuit realization options with various DC-bus structure, power module busbars and capacitor types are introduced and experimentally evaluated. This paper shows that the converter realization with distributed DC-bus, two-layer power module busbar and cylindrical capacitors brings improvements in commutation inductance and practicality.