Speed Sensorless DTC of Induction Motor Based on an improved Adaptive Flux Observer

Abstract

This paper presents a method for estimation of the stator flux components and rotor speed based on the theory of an adaptive control and a direct torque control (DTC). A linear observer for estimation of the stator flux is synthesized, by using a Lyapunov theory in order to guarantee stability for state estimation. The adaptive observer is associated to a direct torque control of an induction motor. To illustrate the performances and the robustness of this observer, a simulation results is presented.

A Novel High Performance Discrete Flux Integrator for Control Algorithms of Fast Rotating AC Machines

“…In the same way, introducing ϕ e as the rotor excitation flux matrix, the flux equation becomes (7).…”

“…In the literature, this function is very well studied, with different types, more or less specific to the machine to control and with different strengths and weaknesses. For example, the sliding mode algorithm [2,3] requires a double integration for currents and fluxes; the Butterworth method presented in [4] present the same double integration plus the need for an additional PI regulator; the dead-beat direct control in [5] is not really ideal for flux estimation, since it looks only at the end torque result; the adaptive model of [6] or, more recently, [7,8] could be very calculation heavy; the methods compared in [9] are just for machines with magnets. Moreover, a flux observer is required for any sensorless application such as permanent magnets [10], reluctance [11], or induction machines [12] that all use the machine equations to find the rotor flux angle, since this operation is intended for applications without the direct measurement of the rotor position and speed.…”