Stator voltage fault detection and optimal rotor current limiting in doubly fed induction generators

Abstract

Summary Doubly fed induction generators are widely used in wind power plants, yet their performance is vulnerable to grid voltage faults. Recent regulations require the wind generator to have the capability of fault crossing to stay connected even in faulty conditions. This paper investigates the problem of stabilizing the rotor current when the stator voltage is affected by the faults that occurred at the nearby grid. The proposed controller consists of 2 terms: the first is responsible for the internal stability of generator dynamics and the second compensates for the effect of the fault on the stator voltage. The stability of generator circuit is verified by using linear quadratic regulator and pole placement criteria. Also, to enhance the performance of the stabilizers, genetic algorithm is used to adjust the stabilizers. To detect the stator voltage disorders and to determine the suitable time for switching in fault stabilizers, a fault observer is also suggested. The fault detection and stabilization structure is simulated and shows higher levels of performance in faulty conditions than in conventional rotor side converter controllers in faulty grid conditions.

Wind turbines sustainable power generation subject to sensor faults: Observer‐based MPC approach

“…20,21 Also, the task of fault tolerant control (FTC) is cost reduction of maintenance and increasing reliability especially for the offshores WTs. [22][23][24] Actuators, sensors, and system faults are the most common faults in the practice. In this study, we focus on the sensor faults of the WT system.…”

“…An important problem in the detection of wind turbine faults is designing a suitable controller during the fault occurrence that causes wind energy reduction and increasing the output performance 20,21 . Also, the task of fault tolerant control (FTC) is cost reduction of maintenance and increasing reliability especially for the offshores WTs 22‐24 . Actuators, sensors, and system faults are the most common faults in the practice.…”

Vector control optimization of DFIGs under unbalanced conditions

“…Moreover, the negative sequence rotor current is needed to be controlled to prevent possible damages to the rotor converter because of overcurrent. 8 Furthermore, the controller must be designed to reduce torque oscillations to prevent depreciation of drivetrain unit. [9][10][11] Meanwhile, the control system must also minimize active/reactive power oscillations caused by negative sequence voltages and currents in order to preserve power quality.…”

“…To avoid insulation fatigue, stator overcurrent caused by voltage unbalances must be controlled. Moreover, the negative sequence rotor current is needed to be controlled to prevent possible damages to the rotor converter because of overcurrent . Furthermore, the controller must be designed to reduce torque oscillations to prevent depreciation of drivetrain unit .…”

Optimal design of a modular axial‐flux permanent‐magnet synchronous generator for gearless wind turbine applications

“…3,4 DCWTs provide many advantages in terms of reliability, maintenance cost, and efficiency in comparison with geared types. 5,6 Nevertheless, owing to the lower speed of DCWTs, the generator of such types of turbines must be designed with a high torque density value to decrease the generator volume and weight. 7 In this respect, permanent-magnet machines are highly interesting for wind turbine applications.…”