GTO Inverter for AC Traction Drives

A 600-kVA capacity GTO inverter for traction drives has been developed using 2500-V/1000-A gate turn-off (GTO) thyristors, and running tests have been carried out. To utilize the advantages of GTO thyristors, circuit inductance of both main loops and snubber loops were minimized in order to decrease overvoltage applied to GTO thyristors after turn-off. Appropriate protection systems for the GTO inverter against commutation failure and overcurrent in traction motors were developed. Running tests for an electric car driven by the GTO inverter showed good control characteristics.