| Abstract |
In high-power GTO converters for traction applications, transfer of the control command and a checkback signal between the control system and the GTO gate units via optical waveguides is nowadays state of the art. The general signal convention for the control command path is "light on" = "GTO should conduct", "light off" = "GTO should block". On the feedback path, as a rule "light on" = "GTO blocking", "light off" = "GTO status unknown". This mode does not make it possible to recognise faults and also affords little checkback information on the system status. The present paper describes a transmission procedure that is fault-tolerant and also affords more status information. This procedure consists of transmission codes for the control command and checkback signals and the code/decode and fault identification methods. It is built up on the principles of: as simple as possible - quick transmission - reduced electronic circuitry for coding and decoding. This procedure makes it possible to monitor the entire "coder => optical fibre => receiver => GTO gate unit => GTO => status identification => optical waveguide => receiver => decoder" loop for proper functioning. |
