Abstract：The voltage model of rotor flux observer is applied, because it is simple. But the model is extremely sensitive to measurement errors at low speed because the voltage drop of stator resistance and the pure integrator of the voltage model has some disadvantages like DC offset and initial value problems. In this paper, an improved rotor flux observer is presented. The stator electromotive force is compensated by introducing the errors between the current model and the voltage model of the stator flux. The ideal integrator is replaced by the new modified low-pass filter. The voltage model of rotor flux is deduced from the voltage model of stator flux. The speed is identified based on the improved rotor flux observer. Simulation and experimental results verify that this strategy improves the dynamic and static performance of the speed identification, especially at low speed.
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2012, Vol. 27 
