| 摘要 |
The invention relates to a method for determining an estimate for the stator flux of an asynchronous machine when the supply frequency ?s, stator inductance Ls, stator resistance Rs or an estimate Rse therefor, and short circuit inductance .sigma.Ls are known, in which method the stator current ?s and stator voltage ?s are measured, a difference voltage is calculated by subtracting the product of the stator resistance or its estimate and the stator current from the stator voltage, and said difference voltage is integrated in relation to time to obtain a stator flux estimate ?se. To improve the accuracy of the estimate, prior to the integration a correction term based on the feedback stator flux estimate ?se and being proportional to the product of the difference variable .epsilon. and the direction vector ? given therefor is subtracted from said difference voltage, said difference variable being determined from the equation: (?se-Ls?s) . (?se-Ls?s) = .epsilon. and the direction vector ? being formed from the feedback stator flux estimate ?se by turning it for the angle .theta. which is dependent on the operational mode of the machine.
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