A STABLE ADAPTIVE FLUX OBSERVER FOR A VERY LOW SPEED-SENSORLESS INDUCTION MOTOR DRIVES INSENSITIVE TO STATOR RESISTANCE VARIATIONS | ||||
| ERJ. Engineering Research Journal | ||||
| Article 10, Volume 32, Issue 2, April 2009, Page 201-210 PDF (325.03 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/erjm.2009.69410 | ||||
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| Author | ||||
| Moharned S. Zaky | ||||
| Electrical Engineering Department, Faculty of Engineering, Minoufiya University, Shebin El-Kom, Egypt | ||||
| Abstract | ||||
| n recent years, numerous attempts have been made to improve the performance of speedsensorless induction motor drives. Adaptive flux observer (AFO) is one of the machine model based methods of speed estimation. Parameter variations, low-speed operation and the difficulty encountered in the design of the feedback gain and the adaptation mechanism are the most critical aspects affecting the accuracy and stability of this method. In this paper, design of the observer feedback gain is proposed to ensure the stability over a wide range of operation especially in the low-speed region. The characteristic equation of the closed loop speed estimator is derived. The values of the adaptive law parameters corresponding to the marginal system stability are determined based on Routh-Hunvitz criterion. The sensitivity of AFO to stator resistance mismatch is studied. A stator resistance adaptation scheme for accurate speed estimation at low speeds is derived using Popov's hyper-stability theory. The relation between the identification error of the rotor speed and adaptive gains is clarified. An experimental setup based on a DSP system is implemented. The simulation and experimental results confirm the efficacy of the proposed approach | ||||
| Keywords | ||||
| Sensorless control; Stability analysis; adaptive law design; low speed; stator resistance estimation | ||||
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