scholarly journals An Improved Droop Control Scheme of a Doubly-Fed Induction Generator for Various Disturbances

Energies ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7980
Author(s):  
Yien Xu ◽  
Pei Chen ◽  
Xinsong Zhang ◽  
Dejian Yang
Keyword(s):  
Rate Of Change ◽  
Frequency Regulation ◽  
Droop Control ◽  
Doubly Fed Induction Generator ◽  
Control Coefficient ◽  
Induction Generators ◽  
Doubly Fed Induction Generators ◽  
Control Scheme ◽  
Doubly Fed ◽  
System Frequency

Doubly-fed induction generators (DFIGs) participate in the system frequency regulation using a fixed-coefficient droop control scheme. Nevertheless, the frequency-supporting capability of this control scheme with fixed gain is limited for different disturbances. This paper suggests an improved droop control scheme for a DFIG that can both alleviate the frequency nadir and maximum rate of change of frequency (ROCOF) during the frequency regulation. To achieve this, an adaptive droop control coefficient based on the ROCOF is suggested. The proposed droop control coefficient is a linear function of the ROCOF. Therefore, the proposed scheme can adjust the control coefficient according to the varying ROCOF. Simulation results clearly demonstrate that the proposed droop control scheme shows better effectiveness in improving the maximum ROCOF and frequency nadir under various sizes of disturbance, even in a varying wind speed.

scholarly journals Fast Stepwise Inertial Control Scheme of a DFIG for Reducing Second Frequency Drop

2021 ◽  
Vol 11 (17) ◽  
pp. 8259
Author(s):  
Yien Xu ◽  
Dejian Yang ◽  
Jiejie Huang ◽  
Xinsong Zhang ◽  
Liang Hua
Keyword(s):  
Wind Speed ◽  
Rotor Speed ◽  
Induction Generators ◽  
Doubly Fed Induction Generators ◽  
Frequency Drop ◽  
Control Scheme ◽  
Grid Codes ◽  
Inertial Control ◽  
Doubly Fed ◽  
System Frequency

With the fast growth in the penetration of wind power, doubly fed induction generators (DFIGs) are recommended for their ability to enforce grid codes that provide inertial control services by releasing rotational energy. However, after supporting the system frequency, a second frequency drop (SFD) is prone to occurring to regain the rotor speed caused by the sudden reduction in output. In this article, we propose a torque limit-based fast stepwise inertial control scheme of a DFIG using a piecewise reference function for reducing the SFD while preserving the frequency nadir (FN) with less rotor energy released. To achieve the first objective, the power reference increases to the torque limit and then decays with the rotor speed toward the preset operating point. To achieve the second objective, the power reference smoothly lessens over time based on the exponential function. The performance of the proposed stepwise inertial control strategy was studied under various scenarios, including constant wind speed and ramp down wind speed conditions. The test results demonstrated that the frequency stability is preserved during the frequency support phase, while the second frequency drop and mechanical stress on the wind turbine reduce during the rotor speed restoration phase when the DFIG implements the proposed stepwise inertial control scheme.

scholarly journals An Analytical Method for Estimating the Maximum Penetration of DFIG Considering Frequency Stability

2020 ◽  
Vol 12 (23) ◽  
pp. 9850
Author(s):  
Mengqi Qing ◽  
Fei Tang ◽  
Fusuo Liu ◽  
Dichen Liu ◽  
Nianchun Du ◽  
...  
Keyword(s):  
Frequency Domain ◽  
Wind Power ◽  
Analytical Method ◽  
Frequency Stability ◽  
Wind Generation ◽  
Induction Generator ◽  
Frequency Regulation ◽  
Doubly Fed Induction Generator ◽  
Doubly Fed ◽  
System Frequency

With the increasing wind power in power systems and the wide application of frequency regulation technology, the accurate calculation of the limit wind power capacity in systems is critical to ensure the stability of the frequency and guide the planning of wind power sources. This paper proposes an analytical method for calculating the maximum wind generation penetration under the constraints of frequency regulation control and frequency stability taking doubly fed induction generator as an example. Firstly, the frequency-domain dynamic model of the doubly fed induction generator is established considering the supplementary frequency proportion-differentiation control under small disturbance. The equivalent inertia time constant of the doubly fed induction generator is calculated. On this basis, the frequency response model of the power system with the consideration of wind power integration in frequency regulation control is constructed. Then, the frequency-domain analytical solution of the system frequency is obtained. Finally, with the constraint by the steady-state deviation and dynamic change rate of the system frequency, the maximum wind generation penetration is analytically solved. The accuracy of the proposed analytical calculation method for the limit value of the percentage of wind power is verified by MATLAB/Simulink.

scholarly journals Descending Viewer Method for Fault Tolerant Control

2018 ◽  
Vol 7 (3) ◽  
pp. 199
Author(s):  
K. Lenin
Keyword(s):  
Fault Tolerant ◽  
Short Circuit ◽  
Fault Tolerant Control ◽  
Doubly Fed Induction Generator ◽  
Strong Condition ◽  
Induction Generators ◽  
Doubly Fed Induction Generators ◽  
Rotor Resistance ◽  
Simulation Results ◽  
Doubly Fed

<span lang="EN-US">In this paper Descending Viewer Method (DVM) projected for finding and fault tolerant control of stator inter-turn short circuit faults in doubly-fed induction generators based in wind turbine. A process has been developed that allows the way from ostensible controllers designed for strong condition, to vigorous controllers designed for defective condition. Finally value of the rotor resistance estimated &amp; is based on the use of the error between real and probable value of doubly fed induction generator (DFIG) in faulty condition, this will perk up the performance of this viewer. Simulation results show the reliability of the proposed Descending Viewer Method (DVM) approach.</span>

scholarly journals Enhanced Inertial Response Capability of a Variable Wind Energy Conversion System

Energies ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 8132
Author(s):  
Jun Wang ◽  
Yien Xu ◽  
Xiaoxin Wu ◽  
Jiejie Huang ◽  
Xinsong Zhang ◽  
...  
Keyword(s):  
Control Strategy ◽  
Maximum Rate ◽  
Rate Of Change ◽  
Frequency Deviation ◽  
Control Coefficient ◽  
Maximum Frequency ◽  
Induction Generators ◽  
Inertial Response ◽  
System Frequency ◽  
Response Capability

An inertial response emulated control strategy of doubly-fed induction generators (DFIGs) is able to arrest their frequency decline following a severe frequency event. Nevertheless, the control coefficient is unchanged, so as to limit the benefit potentiality of improving the inertial response capability for various disturbances and provide less of a benefit for boosting the frequency nadir. This paper addresses an enhanced inertial response emulated control scheme for a DFIG to improve the maximum frequency deviation and maximum rate of change of frequency for various disturbances. To this end, the control coefficient is coupled with the system frequency deviation so as to regulate the control coefficient according to the system frequency deviation (i.e., sizes of the disturbance). Results clearly indicate that the proposed inertial response emulated control strategy provides better performance in terms of improving the maximum rate of change of frequency and maximum frequency deviation under various sizes of disturbance and random wind speed conditions.

scholarly journals Coordinated Secondary Frequency Regulation Strategy of Doubly-Fed Induction Generator and Electric Vehicle

2019 ◽  
Vol 9 (14) ◽  
pp. 2815
Author(s):  
Qian Zhang ◽  
Yan Li ◽  
Chen Li ◽  
Zhuwei Ding ◽  
Wenrui Xie
Keyword(s):  
Wind Speed ◽  
Real Time ◽  
Electric Vehicle ◽  
Time Allocation ◽  
Pitch Angle ◽  
Induction Generator ◽  
Frequency Regulation ◽  
Doubly Fed Induction Generator ◽  
Doubly Fed ◽  
System Frequency

Wind turbines can participate in frequency regulation by controlling active power output, but the indeterminacy and volatility of wind power result in low reliability of frequency support. Therefore, as a kind of energy storage system, an electric vehicle is adopted to coordinate with wind turbines to regulate system frequency considering its large-scale development. First, based on the reasonable division of wind speed regions and operation point selection of pitch angle, the de-loading strategy of doubly-fed induction generator for reserve capacity under continuously varying wind speed is proposed. Then, through the combination of rotor speed and pitch angle control, frequency regulation model of a doubly-fed induction generator in whole wind speed range is established. Finally, taking into account the driving demand of electric vehicle owners, through the real-time allocation of system frequency regulation task based on frequency regulation capacity, the coordinated control strategy of doubly-fed induction generator and electric vehicle cluster for secondary frequency regulation is put forward. The simulation results show that the coordinated frequency regulation strategy based on real-time allocation can suppress frequency deviation effectively, and the regulation effect is better than the situations of wind turbine coordinating with the conventional unit or coordinating with electric vehicle cluster based on fixed allocation ratio.

Sign in / Sign up

Export Citation Format

Share Document