Torque tracking strategy for antislip control in railway traction systems with common supplies

The traction system of the subway VAL 206 is ensured by DC machines connected in series. A common chopper supplies the armature windings and a double-chopper supplies the field windings. Another power structure is suggested in order to increase performances during losses of adhesion. A specific control strategy is defined in order to obtain different torque on both machines despite their common armature current. An antislip control can thus be developed in applying the desired torque to each bogie at just the right time. This torque tracking strategy is validated on a 1.5 kW experimental set-up.