Newer generation Diesel / Electric locomotives, EMUs, DMUs and Metro cars equipped with AC Traction Motors require sophisticated Traction Converters to control these motors as part of propulsion system.

Diesel locomotive and DMU propulsion system architectures provide rectified alternator output as stable DC link bus voltage input to the Traction Converter. Traction Converter could be a combination of one or more inverters each controlling one or more traction motors.

EMU and Electric locomotive propulsion system architectures typically provide secondary winding of traction transformer as input feed to the Traction Converter. Traction Converter would have multiple line converters which convert single phase AC input to a stable DC link bus voltage. A combination of one or more inverters converts this DC bus voltage to 3-phase power controlling one or more traction motors each. For Metro cars, depending on OHE voltage or third rail DC voltage, traction converter may include line converters and inverters or only inverters.