Title: A simple but high-performance IM speed drive

Authors: Giuseppe Buja, Roberto Menis

Addresses: Department of Electrical Engineering, University of Padova, Via Gradenigo 6/a, 35131 Padova, Italy. ' Department of Electrotechnics, Electronics and Computer Science, University of Trieste, Via Valerio 10, 34127 Trieste, Italy

Abstract: The paper deals with an induction motor (IM) speed drive having high performance over a large speed range in the constant torque region. The drive is built up around an outer loop of speed equipped with an incremental encoder and two inner loops of torque and flux implemented in a direct torque control (DTC) scheme. The scheme takes advantage of the available speed to estimate the motor torque and the stator flux magnitude by means of the IM current model. This allows the full exploitation of the drive capabilities even in the low speed range. Furthermore, with a suitable representation of the IM current model, the drive can be operated down up to zero speed. The paper closes by analytically investigating the detuned behaviour of the scheme due to a rotor time constant mismatch. Experimental results substantiate the low-speed capabilities of the scheme and the findings on its detuned behaviour.

Keywords: industrial IM drives; direct torque control; IM current modelling; low-speed operation; detuned behaviour; induction motors; stator flux magnitude.

DOI: 10.1504/IJIED.2009.025347

International Journal of Industrial Electronics and Drives, 2009 Vol.1 No.1, pp.64 - 71

Published online: 19 May 2009 *

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