A STABLE ADAPTIVE FLUX OBSERVER FOR A VERY LOW SPEED-SENSORLESS INDUCTION MOTOR DRIVES INSENSITIVE TO STATOR RESISTANCE VARIATIONS

Document Type : Original Article

Author

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 speed￾sensorless 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

ERJ. Engineering Research Journal
Volume 32, Issue 2
April 2009
Pages 201-210

Files

Share

How to cite

Statistics