Speed estimation of a Doubly Fed Induction Machine controlled by a Field Oriented Control Strategy

Abstract

This paper studies the estimation problem of speed in a Doubly Fed Induction Machine (DFIM) controlled by a Field Oriented Control (FOC) Strategy. The DFIM is the most responsive in variable speed. The chosen configuration uses two voltage inverters connected to the stator and rotor windings, to adopt the power distribution between them through the pulses distribution of the stator and the rotor in motor operating mode. It is necessary to model the DFIM in three-phase equations and then in two-phase equations faithfully representing the characteristics of the machine. From this model, we can design and simulate the control. The control by oriented rotor flux can be realized by using the speed provided by sensors or estimators. In this paper, we have used the Extended Kalman Filter (EKF) in order to avoid problems caused by the motor speed sensor and improve the robustness of the control and its performance without using any speed sensor.