METHOD AND APPARATUS FOR DETERMINING THE TIME CONSTANT OF THE ROTOR OF A FIELD ORIENTATED INDUCTION MACHINE

摘要

1. A method for determining the time constant (T) of the rotor of an induction machine (1), wherein a) from operating data and an input parameter (T) for the time constant of the rotor of an induction machine the direction of flow (angle gamma M ) of a balanced model flow (psi M ) is determined ; b) a respective theoretical value is given for the field-forming (flow-parallel) component (i gamma 1-* ) and the torque-forming (flow-transverse) component (i gamma 2-* ) of the machine current ; and c) the machine stator current (_i) is regulated or controlled in accordance with the flow direction of the two theoretical values of the model flow ; characterised in that d) on the theoretical value (i gamma 1-* ) for the one component is superimposed an interference magnitude (K) having a non-constant time course ; e) the time course of the actual value (n = dt-dn ) of an operating magnitude (number of revolutions n) determined by the other component (i gamma 2-* ) is detected ; f) a correlation magnitude (average of Intg K (t-DELTA) . n (t) . dt=DELTA T) for the correlation in time of the interference magnitude and the detected operating magnitude is determined ; and g) the input parameter (T) for the time constant of the rotor is changed in dependence upon the correlation magnitude (DELTA T) until the correlation magnitude is virtually zero.