Speed estimation of induction motor using modified voltage model flux estimation

Speed estimation in field-oriented vector control of induction motor depends on effective estimation of rotor flux. This paper proposes speed estimator using improved rotor flux estimator based on modified voltage model with a high orders low-pass filter (LPF) and a low-pass filter in series and an error compensator by rotor flux oriented current model. In the flux estimation based on voltage model, a high orders LPF can remove the DC offset input of back EMF, a LPF is normally used to replace the pure integrator to avoid integration drift and saturation problems and the flux estimation error is compensated according to rotor flux oriented current model. The proposed the speed estimator realizes errorless speed estimation in steady state and makes the error of speed estimation smaller in dynamic state. The speed estimation is verified by speed sensorless field-oriented vector controlled 2.2 kW induction motor. Experimental results demonstrate high performance of the speed estimator.