Power Control Of Wind Turbine Research Articles

Reactive power control of DFIG wind turbines for power oscillation damping under a wide range of operating conditions

This study analyses the effect of replacing existing synchronous generators (SGs) equipped with power system stabilisers (PSS) by doubly fed induction generator (DFIG) based wind farms on the damping of power system oscillations in a multi-machine power system. A power system stabiliser was designed to enhance the capability of DFIG to damp power systems oscillations. The validity and effectiveness of the proposed controller are demonstrated on the widely used New England 10-machine 39-bus test system that combines conventional SGs and DFIG based wind farms using eigenvalue analysis and non-linear simulation. The non-linear simulation is used to demonstrate how the damping contribution of DFIG based wind farms is affected by different operating conditions within the same wind farm and stochastic wind speed behaviour. The results show that installing conventional fixed parameters PSS within reactive power control loop of DFIG rotor side converter has a positive damping contribution for a wide range of operating conditions. Furthermore, the results clearly show that DFIG based wind farms equipped with the proposed farm level PSS can damp power system oscillations more effectively than SGs PSS.

LPV-based active power control of wind turbines covering the complete wind speed range

This paper focuses on the active power control of wind turbines. Modern grid codes increasingly demand active power control in order to guarantee utility grid stability under high wind energy penetration. Active power control provides capabilities to regulate wind power below rated, to maintain a power reserve, to indirectly regulate the grid frequency, etc. New controllers are necessary to tackle the extended operating modes and new objectives. This paper addresses the control problem using LPV techniques, since they are particularly suited to cope with the nonlinearities that arise along the extended operating region. The proposed controller was evaluated on a 5 MW wind turbine benchmark. For that purpose, very demanding and realistic testing scenarios were built using the FAST aeroelastic wind turbine simulator as well as standardized wind speed profiles. The proposed controller was compared with the gain scheduled PI traditionally used for wind turbine control and also with a gain scheduled ℋ∞ controller. Finally, a comparative load analysis is presented with the aim of showing that the softer and lower pitch activity of the proposed controller decreases the extreme load events.

An adaptive observer for wind velocity using a new torque model of a wind turbine

ABSTRACTIn this paper, a new mechanical torque model of a wind system is presented, which is used to design an adaptive observer, whose goal is to estimate the wind speed and the mechanical torque in a wind turbine. This adaptive observer allows to obtain, in real time, the turbine maximum power point with wind turbine power control purposes without requiring the precise knowledge of the performance coefficient curve or look-up tables, that are currently used in most control schemes. The new model is compared with a heuristic model and validated with an experimental system.

WIND TURBINE POWER CONTROL

In this paper, we proposed an algorithm of wind turbine power control when it supports maximum extracted power independently of tip speed ratio and/or wind speed. We proved the efficiency of control of small wind turbines in urban regions. We also formulated the conditions and structure of microprocessor operation, described the algorithm of wind turbine power control showing the possible situations and states.

Micro/small wind turbine power control for electrolysis applications

This paper compares the efficiency of three power converter and maximum power point tracking (MPPT) systems for connecting a micro/small wind turbine to an electrolyser stack: a conventional DC–DC voltage converter with hill-climb search (HCS); a novel variable electrolyser cell load controller where the number of series cells varies to allow MPPT; a novel hybrid DC–DC voltage converter integrated with direct-connect circuitry, variable cell control and lookup-based MPPT. The variable cell and hybrid converters demonstrated superior performance, averaging efficiencies 2–4% higher than the conventional converter, reaching near ideal at a wind speed of 7.7 ms−1 due to direct connection. MPPT function measured electrolyser current as a power reference. HCS performed MPPT at approx. 98% of ideal but requiring very advanced function including variable step size and intelligent perturbation to achieve this during dynamic conditions. The variable cell and hybrid converters produced superior MPPT (based on lookup data) to HCS. This demonstrates alternative novel power control and MPPT approaches for low-cost and efficient hydrogen production from micro/small wind-electrolysis systems.

Effective MPPT technique and robust power control of the PMSG wind turbine

Wind generator performance improvement requires sophisticated and robust control techniques to overcome various constraints and achieve optimal aerodynamic energy conversion. Because of the continuously changing nature of the wind, the output power of a wind energy conversion system (WECS) can be maximized if the wind rotor is driven at an optimal rotational speed for a particular wind speed. This is achieved with a maximum power point tracking (MPPT) controller. Over the years, a variety of MPPT studies have been made, but very few provide guidelines to single out the most suited MPPT technique. In this paper, a comprehensive comparison of the four most used schemes has been made in relation to a permanent magnet synchronous generator (PMSG) wind turbine system. These techniques can be classified into various categories. The obtained results show clearly the superiority of the fuzzy logic control (FLC) technique. Using this MPPT approach, the generated power by the turbine is considered to be, in terms of power control, an auxiliary source feeding a grid. To achieve smooth regulation of the active and reactive power exchange between the PMSG and the grid, direct power control, using space vector modulation DPC‐SVM strategy combined with sliding mode control (SMC) is applied in the grid‐side converter. Simulation results show the efficiency and reliability of the control strategy proposed in this paper. © 2015 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

에너지저장장치를 이용한 풍력발전 출력 제어 성능 평가

In this paper, we describe construction of a wind stabilization demo-site and effects of output power control of wind turbines for suppression of ramp rate using ESS (Energy Storage System). It is difficult to control the output power of distributed generator such as wind turbine which of variation is very large. If the large capacity wind farm be interconnected into power system may cause blackout due to Power Quality. For these reasons, the international standards such as Grid-Code is limited to less than 10 [%/min] of renewable energy ramp rate. The case of Korea, government actively conducts propagating large-scale renewable energy for green growth policy, to interconnecting more renewable energy into power system is necessary for stabilization technology. For these reasons, the POSCO consortium has constructed a wind stabilization demo-site that is configured as 500 [kWh] battery energy storage systems can output up to 3 [C-Rate] and two wind turbines rated 750 [kW]. In POSCO consortium, which implements various methods stabilizing output power of wind turbine such as smoothing, section firming and ramp control, we derive the results of long-term demonstration that can be controlled to satisfy to the international standard about ramp rate [%/kW] of wind turbine output power.

A Fuzzy Logic Control Strategy for Doubly Fed Induction Generator for Improved Performance under Faulty Operating Conditions

In this paper, decouple PI control for output active and reactive powers which is the common control technique for power converter of Doubly Fed Induction Generator (DFIG) is presented. But there are some disadvantages with this control method like uncertainty about the exact model, behavior of some parameters or unpredictable wind speed and tuning of PI parameters. To overcome the mentioned disadvantages a fuzzy logic control of DFIG wind turbine is presented and is compared with PI controller. To validate the proposed scheme, simulation results are presented, these results showed that the performance of fuzzy control of DFIG is excellent and it improves power quality and stability of wind turbine compared to PI controller. The Fuzzy logic controller is applied to rotor side converter for active power control and voltage regulation of wind turbine. The entire work is carried out in MATLab/Simulink. Different faulty operating conditions are considered to prove the effective implementation of the proposed control scheme. DOI: http://dx.doi.org/10.11591/ijpeds.v4i4.5966

Maximum power control system for small wind turbine using predicted wind speed

This paper describes a novel approach of maximum power control for small wind turbines by using predicted wind speed data. Because of the moment of inertia of the wind turbine, when using conventional control method, the time lag of control will occur due to turbulence in the environment. Our proposed control system uses future information, which is the predicted wind speed, for wind turbine control. The control algorithm creates a reference trajectory of the rotational speed of the wind turbine. The advantage of using the predicted data is that the controller can operate the wind turbine efficiently so that the rotational speed of the wind turbine catches up with the reference speed at the maximum power point. Simulation results show improvement of generation efficiency compared to the conventional control method. Then we discuss the influence of the prediction error of wind speed on control performance. © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

One-cycle control application to wind turbine power control

Summary In this paper, a one-cycle control (OCC)-based approach for wind turbines equipped with doubly fed induction generators (DFIGs) is presented. The OCC is used to control back-to-back converter which includes generator-side converter and grid-side converter. The former is used for regulating generator speed, and the latter is used for controlling reactive power. Also, particle swarm optimization is used to improve the accuracy of parameters of PI controllers. The proposed approach is studied under different conditions, including load change, fault and nonlinear loads. Also, uncertainty of wind speed is considered. Moreover, a comparison between pulse width modulation (PWM)-based and OCC-based controllers is done. The OCC is a non-linear PWM method so its control technique turns a non-linear switch into a linear path. In contrast to the traditional PWM method, OCC control realizes PWM and fast/nonlinear control simultaneously by modulating the slope of the saw-tooth waveform. The simulation results show that accuracy and speed control of DFIG converter by OCC are superior in comparison with conventional control strategies from tracking reference signal and oscillations point of view. Copyright © 2014 John Wiley & Sons, Ltd.

Adaptive Controller for Drive System PMSG in Wind Turbine

This paper proposes adaptive Maximum Power Point Tracking (MPPT) controller for Permanent Magnet Synchronous Generator (PMSG) wind turbine and direct power control for grid side inverter for transformer less integration of wind energy. PMSG wind turbine with two back to back voltage source converters are considered more efficient, used to make real and reactive power control. The optimal control strategy has introduced for integrated control of PMSG Maximum Power Extraction, DC link voltage control and grid voltage support controls. Simulation model using MATLAB Simulink has developed to investigate the performance of proposed control techniques for PMSG wind turbine steady and variable wind conditions. This paper shows that the direct driven grid connected PMSG system has excellent performances and confirms the feasibility of the proposed techniques. While the wind turbine market continues to be dominated by conventional gear-driven wind turbine systems, the direct drive is attracting attention. PM machines are more attractive and superior with higher efficiency and energy yield, higher reliability, and power-to-weight ratio compared with electricity-excited machines.

A Fuzzy-PI Control Technique Designed for Power Control of Wind Turbine Based on Induction Generator

In this paper, we develop the overall model of the wind energy conversion systems (WECS) structure based on induction generator (IG). The goal of this paper is to control the power generated by the WECS and transmitted to the grid. We propose a new control strategy based on fuzzy logic in order to control the power of the WECS. The main drawback is that the WECS is highly nonlinear. An adaptive Fuzzy-PI power controller is proposed to overcome this problem. A Simulation study is done to validate the strategy used in power control.

Doubly fed induction generator wind turbines with fuzzy controller: a survey.

Wind energy is one of the extraordinary sources of renewable energy due to its clean character and free availability. With the increasing wind power penetration, the wind farms are directly influencing the power systems. The majority of wind farms are using variable speed wind turbines equipped with doubly fed induction generators (DFIG) due to their advantages over other wind turbine generators (WTGs). Therefore, the analysis of wind power dynamics with the DFIG wind turbines has become a very important research issue, especially during transient faults. This paper presents fuzzy logic control of doubly fed induction generator (DFIG) wind turbine in a sample power system. Fuzzy logic controller is applied to rotor side converter for active power control and voltage regulation of wind turbine.

Active and Reactive Power Control for Wind Turbine Based on a MIMO 2-Sliding Mode Algorithm With Variable Gains

This study proposes a power control strategy for a grid-connected variable-speed wind turbine, based on a doubly-fed induction generator (DFIG) with slip power recovery. The control objectives vary with the zones of operation (dependant on the wind speed), aiming to maximize the active power in the partial load zone and to limit it when operating within the full load zone, while regulating the stator reactive power following grid requirements. The control design, based on the second-order sliding modes (SOSM) and Lyapunov, uses a modified version of the super-twisting algorithm with variable gains which can be applied to nonlinear multiple inputs-multiple outputs (MIMO) systems. The well-known robustness of the sliding techniques, the simplicity of the algorithm, and the adaptive characteristic of its gains are used together in this study to obtain a controller able to deal robustly with the exacting challenges presented by these systems. An additional benefit of the proposal lies in the smoothness of the control action, an important issue regarding applied mechanical efforts. Representative results obtained by simulation of the controlled system are shown and discussed.

Optimal tracking and robust power control of the DFIG wind turbine

In the present paper, an optimal operation of a grid-connected variable speed wind turbine equipped with a Doubly Fed Induction Generator (DFIG) is presented. The proposed cascaded nonlinear controller is designed to perform two main objectives. In the outer loop, a maximum power point tracking (MPPT) algorithm based on fuzzy logic theory is designed to permanently extract the optimal aerodynamic energy, whereas in the inner loop, a second order sliding mode control (2-SM) is applied to achieve smooth regulation of both stator active and reactive powers quantities. The obtained simulation results show a permanent track of the MPP point regardless of the turbine power-speed slope moreover the proposed sliding mode control strategy presents attractive features such as chattering-free, compared to the conventional first order sliding technique (1-SM).

The Analysis of Power Performance for Small H-Vertical Axis Wind Turbine

This paper mainly aims to get rotor aerodynamic performance curve and has studied the matching between the rotor and generator based on the numerical simulation method of the computational fluid dynamics, using the finite volume method to calculate the pneumatic performance of H-type wind power generator, so as to provide guidance for the power control of the small h-vertical axis wind turbine.

Power Control of Wind Turbine based on Fuzzy Controllers

In this paper, we develop the overall model of the wind energy conversion system (WECS) structure based on induction generator (IG), and propose a study of the electrical parts (induction machine and static converter). Our study is developed on a wind conversion system in order to produce optimum power and to extract the maximal wind power. The goal of this paper is to control the power generated by the WECS and transmitted to the grid. We propose a new control strategy based on fuzzy logic in order to control the power generated by the WECS. The main drawback is that the WECS is highly nonlinear, and thus a nonlinear control strategy is required. An adaptive fuzzy power controller is proposed to overcome this problem. A simulation study is done to prove the validation of the strategy used in power control.

Modeling and application of permanent magnet synchronous generator (PMSG) based variable speed wind generation system

n the early development of wind energy, the majority of wind turbines were operated at constant speed. Recently, the number of variable-speed wind turbines installed in wind farms has increased and more wind turbine manufacturers are making variable-speed wind turbines. In this paper, maximum power control of wind turbine and permanent magnet synchronous generator connected with two back to back voltage source converters to grid are studied. Machine currents are controlled by indirect vector control method. In this method, generator side converter controls the maximum excitation (air gap flux) by machine's d-axis current and controls generator torque by machine's q-axis current. Permanent magnet synchronous generator (PMSG) speed is controlled by tip speed ratio upon the wind speed variations to generate the maximum output power. Grid side converter regulates the DC link voltage and injective active power by d-axis current and regulates the injective reactive power by q-axis current using simple control method P-Q. Simulation results depict that the proposed method operates properly. Key words: Wind turbine, permanent magnet synchronous generator, maximum power control, superconductive inductor.

Maximum power point tracking of variable speed wind energy conversion system

This paper proposes a simple method to maximum power control of wind turbine and induction generator connected with two back to back voltage source converters to grid. Machine currents are controlled by indirect vector control method. In this method, generator side converter controls the maximum excitation (air gap flux) by machine's d-axis current and controls generator torque by machine's q-axis current. Induction generator speed is controlled by tip speed ratio (TSR) upon the wind speed variations in order to generate the maximum output power. Grid side converter regulates the DC link voltage and injective active power by d-axis current and regulates the injective reactive power by q-axis current using simple control method P-Q. Simulation results show that the proposed method operates correctly.

Small wind turbine power control in intermittent wind gusts

This paper analyzes control strategies for a small scale wind turbine in intermittent winds using a computer model based on wind data collected on-site and computer simulation data. Standard generator control with a lowered gain was found to produce the greatest power capture by biasing the rotational speed towards high energy wind gusts. Optimal gain was able to be determined by calculating an estimated wind speed using physical and measured quantities. An augmentation to the standard control provides a method for capturing power safely beyond the rated wind speed.