Title: Design and implementation of a MRAS sliding mode observer for the inverse of the rotor time constant of the induction motor

Authors: Mihai Comanescu

Addresses: Department of Engineering, Penn State Altoona, 3000 Ivyside Park, Altoona, PA 16601, USA

Abstract: The paper presents an estimator for the inverse of the rotor time constant of the induction motor. Estimation is done using a sliding mode observer under the assumption that the stationary frame fluxes are known. With measured voltages, currents, and with known fluxes and speed, the paper develops an MRAS-type sliding mode observer. This works well under ideal conditions; however, if the speed is inaccurate or if the magnetising inductance saturates, the accuracy suffers. The paper develops a model for the saturated induction motor and attempts to also estimate the saturation level. In the second part, an observer with only a single set of feedback terms is developed. This is transformed into a sensorless observer by feeding it with a speed estimate (assumed inaccurate). The error in the estimated rotor time constant can be reduced by operating the motor drive with a low ratio of i_d to i_q.

Keywords: induction motor control; model reference adaptive control; rotor time constant estimation; sliding mode observer; voltage model observer.

DOI: 10.1504/IJPELEC.2018.088377

International Journal of Power Electronics, 2018 Vol.9 No.1, pp.52 - 78

Received: 02 Jan 2017
Accepted: 23 Apr 2017
Published online: 05 Dec 2017 *

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