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 coordinate 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. INDEX TERMS Doubly fed induction generator (DFIG), predictive control, flux control, torque control, sensorless, flux estimation, current estimation, finite control set (FCS).

Improving the Dynamic Performance of a Variable Speed DFIG for Energy Conversion Purposes Using an Effective Control System

“…Due to the several advantages of the DFIG as a generation unit, researchers have made great efforts to develop various control techniques and then test them with the DFIG. In [21][22][23][24][25], the vector orientation control (VOC) technique is performed, while in [26][27][28], the direct torque control (DTC) technique is used. The VOC technique has been performed in various configurations according to the selected variable to be aligned with the direct (d) axis of the rotating synchronous frame.…”

“…The VOC technique has been performed in various configurations according to the selected variable to be aligned with the direct (d) axis of the rotating synchronous frame. For instance, in [21], the stator field was chosen to rotate with a speed equal to that of the synchronous frame, while in [22], the stator voltage was chosen to be aligned with the direct axis of the synchronous frame. In [23][24][25], the rotor field was chosen to be oriented in the same direction as the direct axis of the rotating frame.…”

Performance Enhancement of a Hybrid Renewable Energy System Accompanied with Energy Storage Unit Using Effective Control System

“…But on the other hand, they suffered from the need for a separate excitation source. After that, the doubly-fed induction generator (DFIG) came into consideration [22][23][24][25], which possessed several merits, such as using power converters with a lower rating which saves the cost, in addition to the ability to ride through the fault occurrence. However, the DFIG suffered from the high maintenance cost and reduced efficiency due to the copper losses.…”

Robust Flux and Speed State Observer Design for Sensorless Control of a Double Star Induction Motor

“…In practice, the state observer takes two different forms, a reduced order observer, where only the immeasurable state variables of the system are reconfigured [22][23][24], and a full order observer, for which all state variables of the system are reconfigured. The performance of this structure obviously depends on the choice of the gain matrix [25][26][27][28][29]. Unfortunately, rare studies in the literature were concerned with the sensorless operation of double star IM; some of them used the sliding mode observers [30], and others adopted the MRAS estimator [31,32].…”