Sensor-less speed control of an induction motor with no influence of secondary resistance variation

Calculation methods for the rotor and the secondary resistance of an induction motor are proposed. The first method is a rotor speed calculation method by which the exact speed can be computed directly. The method does not require information about the secondary resistance, which makes it free from the variation of the secondary resistance. The second method is a direct secondary resistance calculation method. It can be applied to compensation in speed sensorless vector control for exact speed extimation of a secondary resistance. The effectiveness of the proposed methods was verified by digital simulation and experimental results. The influence of the machine and control circuit parameters is also examined.<
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