New scheme of sliding-mode control for high performance induction motor drives

A new sliding mode control approach for induction motor drives is presented. The control algorithm is based on the model of an induction motor in a frame rotating synchronously with the stator current vector. As with the indirect vector control of induction motor, the method allows rotor flux and torque to be controlled by two independent control variables. The distinct advantage of the proposed method lies in its insensitivity to motor parameter variations. Since the control law is represented in a set of inequalities instead of equalities, as the motor parameters change, the stability of the sliding mode and the feature of independent control of the flux and torque will not be destroyed as long as the corresponding inequalities hold. Experiment results have verified the advantages of the method.