Induction motor stator flux measurement using a finite impulse response digital filter

With direct torque control of induction motors,the stator flux is usually observed based on the U-I model.However,the DC and low-frequency components reduce the accuracy of the stator flux measurement which reduces the motor performance.This paper describes a combination of the U-I model and the Finite Impulse Response Digital Filter that gives more accurate measurement.Experiments comparing the combined method with traditional U-I observations and observations based on a Chebyshev filter show that the combined method gives more precise stator flux measurement over a large motor speed range which improves the motors' performance fed by direct torgue control.