Decoupled flux and torque control schemes for high performance induction motor drive systems: a comparative study with various new strategies

In order to obtain high-performance drives with induction motors one must ensure vector decoupling between flux and torque control loops. The authors present a systematic study of the various strategies proposed to achieve this vector decoupling in an induction motor drive system. The decoupling strategies are grouped into two broad classes: vector-slip and quadrature strategies. The choice of an appropriate set of state variables for representing the motor as well as an adequate reference frame leads one to use standard controllers in the flux and torque loops. The comparison between the strategies is done via digital simulation for a standard VSI-PWM induction motor drive