| 摘要 |
<p>The present invention relates to methods and to devices for improving the automatic control of an asynchronous motor (10) having a stator (12), and a rotor (13) comprising magnetic anisotropy, wherein the asynchronous motor (10) is automatically controlled by means of a model, in particular a field-based automatic control model which is supplied with time-dependent measured voltage and/or current values which are dependent on magnetic fields that occur in the asynchronous motor (10), and wherein the model takes into account at least one variable parameter, wherein moreover the variations in the measured current and/or voltage values generated by the magnetic anisotropy of the rotors (13) are evaluated in an anisotropy evaluator (21), and from the evaluation result a current slip frequency and/or rotational speed of the rotor (13) is determined. According to the invention, this is done by determining deviations of the model parameter from a value that is desirable for reasons pertaining to automatic control engineering, by comparing the current slip frequency or rotational speed obtained in the anisotropy evaluator (21) to a corresponding estimated value obtained based on the model, and by changing the parameter until the current slip frequency or rotational speed estimated based on the model, and the one determined by the anisotropy evaluator (21) are substantially in agreement. The invention also relates to an associated measurement system having a rotor (13) of an asynchronous motor (10), which is constructed from individual ferromagnetic metal plate layers (11), wherein the metal plate layers as a whole define a preferential direction (P) with regard to the magnetisability of the rotor (13), resulting during operation in an anisotropic magnetic field rotating with the rotor (13), wherein voltage and/or current transducers(18) are associated with the asynchronous motor (10), and wherein means (21) are present for the selective evaluation of the effects of the anisotropy of the time-dependent currents and/or voltages measured by the voltage and/or current transducers (18). The invention allows a precise, encoderless, automatic control of rotational speed at low cost.</p> |
