Evaluation of different high-voltage switch solutions for high-power converters used in rolling stock

Feeding of rolling stock power converters by high-voltage DC catenary (3.0 kV DC) is complicated because of wide variations in supply voltages (2.0 kV...3.6 kV). The most efficient and simple topology for the rolling stock voltage converters is a two-level VSI directly connected to the traction catenary. This requires primary inverter switches with high voltage blocking capability to be implemented. Basically, the implementation of high-voltage switch is often a tradeoff between compactness, complexity, efficiency, and cost. This paper presents a comparison between different solutions for the 400 A/6.5 kV switch for the 3.0 kV DC catenary-fed rolling stock power converters. The main criteria of comparison are: complexity, switching performance, efficiency, and implementation costs. Some generalizations and practical considerations are provided.