Velocity Control Using Sliding Mode Control Based on Singular Perturbation Theory for Induction Motors

Abstract

In this thesis, we propose sliding mode velocity controller based on singular perturbation for induction motor to improve velocity tracking performance. By using singular perturbation theory, we design input voltage to ensure that the boundary-layer system is globally exponentially stable. In singular perturbation theory, we use two invariant manifolds, slow and fast manifolds. By defining a new time variable, fast manifold approaches to zero. The reduced-order model, which is only consist of slow model, is obtained by using the quasi-steady state. Then, sliding mode velocity and flux control are proposed to improve velocity and flux tracking performance. Rotor speed and stator phase currents are measured, but rotor flux and load torque, which are not measured values, are estimated. Simulation and experimental results validate the effectiveness of the proposed method.