State Transitions in Vector Controlled AC Tram Drive

The paper deals with the control strategy for the prototype AC tram drive designed for modernization of existing trams in Poland. The basis of the drive are vector-controlled induction motors sourced from voltage inverters. Motor shaft speed sensing enables torque and rotor flux indirect control in stator-current oriented co-ordinates system. In the paper the block scheme of such a control is given and distinct work-states of the drive during the tram driving by motorman are described. Traction properties of the drive were checked during street tests of the tram. During tests the behavior of the drive in dynamic states while accelerating and electromagnetic braking of the tram was especially observed. Results of these observations at different tram drive operation conditions in a form of torque and speed transients were enclosed.