Control of induction motors with winding commutation for traction applications

This paper deals with a direct vector control induction motor drive, for electrical vehicle (EV) applications, that, in order to get high peak torque value over a wide frequency range, employ an induction motor with winding commutation. The stator windings are series connected at low speed and parallel connected at high speed, thus a constant voltage supply region of 1:n is reached from the point of view of the whole drive, while 1:(n/2) constant voltage supply region is reached from the point of view of the motor. The motor characteristics, both with series and parallel windings, are analyzed and experimentally verified. The winding changeover procedure, with direct field oriented control, is presented with experimental results.