Improved rotor flux estimation at low speeds for torque MRAS-based sensorless induction motor drives

Andrew N. Smith, Shady M. Gadoue, John W. Finch

Research output: Contribution to journalArticlepeer-review


In this paper, an improved rotor flux estimation method for the Torque model reference adaptive schemes (TMRAS) sensorless induction machine drive is proposed to enhance its performance in low and zero speed conditions. The conventional TMRAS scheme uses an open loop flux estimator and a feedforward term, with basic low pass filters replacing the pure integrators. However, the performance of this estimation technique has drawbacks at very low speeds with incorrect flux estimation significantly affecting this inherently sensorless scheme. The performance of the proposed scheme is verified by both simulated and experimental testing for an indirect vector controlled 7.5-kW induction machine. Results show the effectiveness of the proposed estimator in the low- and zero-speed regions with improved robustness against motor parameter variation compared to the conventional method.

Original languageEnglish
Article number7299286
Pages (from-to)270-282
Number of pages13
JournalIEEE Transactions on Energy Conversion
Issue number1
Publication statusPublished - 1 Mar 2016

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  • Flux estimation
  • induction motor
  • model reference adaptive system (MRAS)
  • sensorless vector control


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