High voltage, chopper for electrical traction applications using series connection of large GTO thyristors

Abstract

The authors present considerations for the series connection of GTOs (gate turn-off thyristors). Criteria for the selection of GTOs, design of snubbers, and adoption of GTO control are given. The advantages and drawbacks of the strategies used are discussed. Detailed experimental results concerning the GTO commutations and the snubber circuit are presented. The influence of important parameters, such as the load current, on the transient and steady-state voltage distribution on the GTOs is discussed. As series connection of GTOs is liable to be used in the high-voltage static converters utilized in rail traction systems, two industrial realizations are considered.<>