A new field oriented controller utilizing spatial position measurement of rotor end ring current

An approach to induction motor field-oriented control is proposed which utilizes measurement of the spatial position but not amplitude of the rotor end ring currents. Since drift problems caused significant errors in the amplitude measurement inherent in previous schemes, the method is considerably more robust than previously reported controllers. The motor torque can be accurately controlled even down to zero-frequency operation. The controller is completely independent of rotor-time-constant variations.<
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