On-line full state and parameter estimation in induction motors and application in control and monitoring

Induction motors are known to be of great interest for industrial applications but at the same time to be difficult to control, basically because of nonlinearities in the variables to be controlled, unavailable measurements, and significant variations in the electrical parameters while operating. In this note, an observer is proposed for state and parameter estimation of all usually unmeasured variables, that is only using measurements of stator currents and rotor speed. Estimation results are shown in simulation, as well as the effect on flux and torque tracking control when using the obtained estimates, and their possible use in detecting abrupt parameter variations.