Position Control of the Induction Motor Using an Adaptive Sliding-Mode Controller and Observers

An adaptive robust position control for real-time high-performance applications of induction motors is developed in this work. The proposed sliding-mode controller provides a global asymptotic position tracking in the presence of model uncertainties and load torque variations. The proposed control scheme incorporates an adaptation law for the switching gain, so that the controller can calculate the switching gain value that is necessary to overcome the existing system uncertainties. The design also incorporates a sliding-mode-based load torque and rotor flux observers in order to improve the control performance without using sensors that increase cost and reduce reliability. The proposed design does not present a high computational cost and, therefore, can be easily implemented in real-time applications. Simulated and experimental results show that this scheme provide high-performance dynamic characteristics, and that it is robust with respect to plant parameter variations and external load disturbances.

I. Introduction

INDUCTION motors (IMs) have been widely used in industrial applications such as machine tools, steel mills, and paper machines, owing to their good performance provided by their solid architecture, low moment of inertia, low ripple of torque, and high initiated torque. In order to regulate the IM in high-performance applications, several control techniques have been developed, being the field-oriented control method [1] one of the most popular techniques.