Cost-Effective Predictive Flux Control for a Sensorless Doubly Fed Induction Generator

Abstract

The paper introduces a cost effective predictive flux control (PFC) approach for a sensorless doubly fed induction generator (DFIG). The base operation of the proposed PFC depends on controlling the rotor flux (α-β) components using a cost function which is derived through analyzing the relationship between the developed torque and the angular slip frequency. To improve the rotor flux estimation and prediction, an effective rotor flux observer is proposed. A robust rotor position estimator is proposed to guarantee a precise co-ordinate transformation. In order to save the cost, only one rotor current sensor is utilized to evaluate the rotor currents. The finite control set (FCS) principle is utilized to select the voltage vectors which enables the elimination of the pulse width modulation (PWM). To validate the feasibility of the proposed sensorless PFC approach, a comprehensive comparison is carried out between the proposed sensorless PFC and the predictive torque control (PTC) for the DFIG. The obtained results confirm and emphasize the superiority of the proposed PFC in achieving the control objectives with lower ripples content and less computational burdens. Moreover, the effectiveness of the rotor position and rotor flux estimators has been confirmed through the obtained results.