Integral-variable-structure-control-based adaptive speed estimator and resistance identifier for an induction motor

The proposed system adopts neither position nor velocity sensor but uses only measurement of the stator current and stator phase voltage commands to estimate the rotor velocity and to identify the resistance of the stator and rotor for an ac induction motor. In the proposed scheme, the integral variable structure control approach is firstly applied to design an observer and identifier. Also, Lyapunov functions are chosen for determining the adaptive law for a speed estimator and a resistance identifier of an induction motor. Simulation results demonstrate that the proposed approach can achieve accurate speed estimation and resistance identification under load disturbance and motor parameter variation.