Analysis of implementation possibilities and benefits of three-level half-bridge NPC topology in static auxiliary converters for rolling stock

This paper is focused on the high-voltage (≥2 kV) high-power (≥20 kW) isolated DC/DC converters for the rolling stock applications. The 3.3 kV IGBT based three-level half-bridge neutral point clamped (NPC) inverter topology was analyzed as an alternative to the two-level half-bridge with 6.5 kV IGBTs. The properties of primary switches, theirs selection procedure as well as inverter loss distribution and design challenges of both concurrent topologies were evaluated and compared.