Traction technology of the new class S252 and S447 power units for the Spanish Railways Renfe

To meet future requirements, the Spanish National Railways Renfe has ordered 75 high-performance locomotives of Class S252 and 71 electrical multiple units of Class S447 with an option of 110 further units. Both vehicles are equipped with modern AC traction technology and digital control systems. The author describes the design of the vehicles, the power circuits of both converter systems, the induction traction motors, and the microcomputer-based control. Both projects clearly show that AC drive systems using induction motors and GTO (gate turn-off thyristor) PWM (pulse width modulation) inverters can be successfully used in modern rail vehicles. Multisystem circuits can be implemented without excessive additional cost. Individual axle control is now state of the art for high-performance vehicles. Microcomputer controls for traction and central functions have made it possible to provide future-proof concepts.<>