Query on Vector Control of Induction Motors


In Vector control of induction motor, stator currents iqs (torque component of stator current) and ids (field component of stator current) are controlled separately just as in the case of a separately excited DC motor by keeping either of the current components constant.

My question is, how is such independent control electrically possible in induction motors when the rotor current itself is dependent on the rotating magnetic field (ids) by transformer action. How does rotor current increase or decrease independently without varying field current ids?

Iqs is just the reflected rotor current and should have no direct influence whatsoever on the rotor current iqr and hence output torque, as iqr is a result of induction due to the rotating magnetic field (ids).