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Showing papers on "Blade pitch published in 2016"


Journal ArticleDOI
TL;DR: The simulation results confirm that the coordinated control of blade pitch angle of wind turbine generators and plug-in hybrid electric vehicles using MPCs is able to reduce the number of PHEVs and the frequency fluctuation can be maintained significantly.
Abstract: This paper proposes coordinated control of blade pitch angle of wind turbine generators and plug-in hybrid electric vehicles (PHEVs) for load frequency control of microgrid using model predictive controls (MPCs). The MPC is an effective model-based predictive control, which calculates future control signals by optimization method using plant model, current, and past signals of the system. The MPC-based PHEVs' power control can be used to reduce frequency fluctuation of microgrid effectively. However, for large system, large number of PHEVs is needed to produce satisfying frequency deviation. In order to reduce the number of PHEVs, the smoothing of wind power production by pitch angle control using MPC method is proposed and is coordinated with PHEVs control in this paper. The simulation results confirm that the coordinated control of pitch angle and PHEVs using MPCs is able to reduce the number of PHEVs and the frequency fluctuation can be maintained significantly. In addition, the proposed method is robust to the system parameters variation over proportional–integral derivative controllers.

186 citations


Journal ArticleDOI
TL;DR: In this article, the axial induction-based control of wind turbines is investigated in which the generator torque or blade pitch degrees of freedom of the wind turbines are adjusted to improve the performance of the turbines.
Abstract: Wind turbines are typically operated to maximize their performance without considering the impact of wake effects on nearby turbines. Wind plant control concepts aim to increase overall wind plant performance by coordinating the operation of the turbines. This paper focuses on axial-induction-based wind plant control techniques, in which the generator torque or blade pitch degrees of freedom of the wind turbines are adjusted. The paper addresses discrepancies between a high-order wind plant model and an engineering wind plant model. Changes in the engineering model are proposed to better capture the effects of axial-induction-based control shown in the high-order model. Copyright © 2015 John Wiley & Sons, Ltd.

171 citations


Journal ArticleDOI
TL;DR: This study proposes to ensure an optimal mechanical power generated by a wind turbine in a chain for a wide range of winds by implementing a pitch control in order to tap maximum energy at wind speeds lower than rated wind speed.
Abstract: Wind power generation has grown at an alarming rate in the past decade and will continue to do so as power electronic technology continues to advance. In this article, this study proposes to ensure an optimal mechanical power generated by a wind turbine in a chain for a wide range of winds. The amount of power output from a wind energy conversion system depends upon the accuracy with which the peak power points are tracked by the maximum power point tracking (MPPT) method searches an optimal operating point from the slope of the power rotational. This can be achieved by implementing a pitch control in order to tap maximum energy at wind speeds lower than rated wind speed, since the proposed method selects the operating mode according to the wind speed. If the wind speed exceeds its rated value, blades are controlled to limit the electrical power to its nominal value. Pitch angle control is the most common means for adjusting the aerodynamic torque of the wind turbine. A fractional pitch angle controller is developed in this paper. The fractional control strategy may reach the potential when the system contains strong non-linearity, especially when the wind turbulence is strong. The controller PI classical and PIα fractional in pitch angle control are compared with the wind gust disturbance. The simulation tests were conducted using MATLAB/Simulink.

78 citations


Journal ArticleDOI
TL;DR: It is clear that fuzzy PID controller performed better than PI and Fuzzy Controller in simulation comparisons of controllers with Matlab/Simulink Software.
Abstract: This article presents a study on set of PID parameters of blade pitch angle controller of wind turbine with fuzzy logic algorithm. Three individual control methods were used to control the wind turbine pitch angle. These control methods are conventional PI, fuzzy and fuzzy PID. With the use of these control methods, the system was protected from possible harms in high wind speed region and maintained changing of nominal output power. It was aimed to the control the wind turbine blade pitch angle in different wind speeds and to hold the output power stable in the set point by simulation of controllers with Matlab/Simulink Software. By evaluating the steady state time of output power received from the simulation results and steady state errors, the performances of the control systems have been measured and compared with one another. As a result of these simulation comparisons, it is clear that fuzzy PID controller performed better than PI and Fuzzy Controller.

65 citations


Journal ArticleDOI
Qing'an Li1, Junsuke Murata1, Masayuki Endo1, Takao Maeda1, Yasunari Kamada1 
15 Oct 2016-Energy
TL;DR: In this article, the effect of turbulence intensity and wind shear on the power characteristics of a two-bladed HAWT was analyzed by using a wind tunnel experiments, and the results showed that the power coefficient was strongly dependent on the blade pitch angle and yaw angle.

63 citations


Journal ArticleDOI
TL;DR: In this paper, a fuzzy logic controller for individual pitch control (IPC) of a wind turbine was designed in order to optimize a trade-off among several control objectives such as blade root moment and generator torque.
Abstract: With the increasing size of modern large wind turbine (WT), the effects of dynamic loading on the structures become an important influence factor. There are mitigation measures for WT control systems to reduce these imbalance structural loads and regulate power. It has motivated the development of blade individual pitch control (IPC) methodologies. This study focuses on the design of fuzzy logic controller (FLC) for IPC. The controllers are designed in order to optimise a trade-off among several control objectives such as blade root moment and generator torque. Three different FLC had been used in the controllers, the first one related to blade pitch angle and electromagnetic torque control variables to meet specified objectives for operation region, the second control model and the third model related to d-q axis blade moment in non-rotating frame of reference. Likewise, the optimisation criteria of FLC consider for each controller objective to mitigate fatigue loads and regulate output power. Finally, the effectiveness of proposed method is verified by simulation results for three-bladed NREL 2 MW WT. The results proved that the fatigue loads in the turbine are reduced obviously.

62 citations


Journal ArticleDOI
TL;DR: In this paper, a top-down approach was used to develop the FAST model, starting with modeling the blades and working down to the mooring system, and validated simulation results against field measurements.

59 citations


Journal ArticleDOI
TL;DR: In this paper, the feasibility of a flexible bladed (or morphing) VAWT, wherein individual blades are able to passively adapt to local flow conditions and serve as a pitch control mechanism to increase rotor efficiency, was investigated.

57 citations


Journal ArticleDOI
TL;DR: The survey results show that the proposed ELM model is suitable and precise for sensor-less wind speed predictions and has much higher performance than the other approaches examined in this study.

56 citations


Journal ArticleDOI
TL;DR: In this article, a detailed investigation of the scale effects on the open water characteristics of a moderately skewed 4-bladed controllable pitch propeller is presented, where the influence of duct design on the flow characteristics, as well as the blade and duct forces in model and full scale conditions, has been studied using three ducts of different design.

56 citations


Journal ArticleDOI
TL;DR: In this paper, an aerodynamic model based on double multiple streamtube theory coupled with an airfoil table lookup based blade element theory analysis and attached unsteady aerodynamics is used for performance prediction.

Journal ArticleDOI
Xin Shen1, Hong Yang1, Jinge Chen1, Xiaocheng Zhu1, Zhaohui Du1 
TL;DR: In this article, the authors optimized the wind turbine blades with 3D stacking line to increase the annual energy production and have better starting behavior compared with 2D-optimized blade geometries.

Journal ArticleDOI
TL;DR: In this article, the effect of solidity, number of blades, tip speed ratio, Reynolds number, fixed blade pitch angle, and blade thickness on the aerodynamic efficiency of the H-Darrieus type is evaluated using the same performance evaluation set-up in order to determine what would be the best aerodynamic configuration and operation parameter in a given application.
Abstract: A parametric study of vertical axis turbines of the H-Darrieus type is conducted using state-of-the-art Computational Fluid Dynamics (CFD) and the k-ω Shear Stress Transport RANS model in its unsteady form. Although most parameters have previously been investigated individually, the effect of solidity, number of blades, tip speed ratio, Reynolds number, fixed blade pitch angle, and blade thickness on the aerodynamic efficiency of the turbine is evaluated using the same performance evaluation set-up in order to determine what would be the best aerodynamic configuration and operation parameter in a given application. The quantitative impact of 3D effects associated with the blade aspect ratio and the use of end-plates is also investigated. For high-Reynolds applications, optimal radius-based solidity is found to be around σ=0.2, while higher solidities show a lower maximum efficiency than what was previously published using simpler streamtube based methods. In 3D, a small blade aspect ratio ( AR=7) leads to...

Journal ArticleDOI
TL;DR: In this article, an active power curtailment strategy for small wind turbines to prevent overvoltage by controlling the pitch angle of the turbine blades is proposed. But, the proposed strategy is only activated when needed, and it is activated only when needed.
Abstract: Overvoltage is a major limiting factor for the integration of distributed generation in distribution systems. Among various solutions to the overvoltage problem, active power curtailment is an attractive solution since only small adjustments in the controllers are necessary for implementing this technique. Furthermore, it is activated only when needed. In wind energy systems, this can be achieved by adjusting the pitch angle of a wind turbine. The objective of this paper is to develop an active power curtailment strategy for small wind turbines to prevent overvoltage by controlling the pitch angle of the turbine blades. The required blade pitch angle was calculated by using the voltage droop method. The developed control strategy was validated by a real time simulation of a rural feeder model developed using RT-Lab software. The feeder is based upon a North American rural distribution network consisting of 96 small wind turbines of 20 kW, a 30 MVA distribution substation with an on-load tap-changing transformer, a rural feeder with 288 houses, a 120 kV/25 kV LV transformer, and rural loads. The results show the effectiveness of the method in keeping the voltage within acceptable limits and a reduction in network losses.

Journal ArticleDOI
TL;DR: The new IGA approach has more successfully adjusted the blade pitch of a WT running at higher wind speeds than other GA methods, and its superiority has been proved by comparing the other genetic algorithm (GAs).
Abstract: Output powers of wind turbines (WTs) with variable blade pitch over nominal wind speeds are controlled by means of blade pitch adjustment. While tuning the blade pitch, conventional proportional–integral–derivative (PID) controllers and some intelligent genetic algorithms (IGAs) are widely used in hot systems. Since IGAs are community-based optimisation methods, they have an ability to look for multi-point solutions. However, the PID parameter setting optimisation of the IGA controllers is important and quite difficult a step in WTs. To solve this problem, while the optimisation is carried out by regulating mutation rates in some IGA controllers, the optimisation is conducted by altering crossover point numbers in others. In this study, a new IGA algorithm approach has been suggested for the PID parameter setting optimisation of the blade pitch controller. The algorithm rearranging both the mutation rate and the crossover point number together according to the algorithm progress has been firstly used. The new IGA approach has also been tested and validated by using MATLAB/Simulink software. Then, its superiority has been proved by comparing the other genetic algorithm (GAs). Consequently, the new IGA approach has more successfully adjusted the blade pitch of a WT running at higher wind speeds than other GA methods.

Journal ArticleDOI
Qing'an Li1, Yasunari Kamada1, Takao Maeda1, Junsuke Murata1, Kohei Iida1, Yuta Okumura1 
15 Mar 2016-Energy
TL;DR: In this article, the authors focus on the evaluation of aerodynamic forces depending on suppressing undesired turbine's motion by a rotor thrust control which is controlled by pitch changes with wind tunnel experiments.

Journal ArticleDOI
01 Sep 2016
TL;DR: In this paper, the axial induction-based control of two in-line model turbines was investigated in a wind tunnel and it was shown that the radial distribution of kinetic energy in the wake area can be controlled by modifying the upstream turbine's tip speed ratio.
Abstract: In state-of-the-art wind farms each turbine is controlled individually aiming for optimum turbine power not considering wake effects on downstream turbines. Wind farm control concepts aim for optimizing the overall power output of the farm taking wake interactions between the individual turbines into account. This experimental wind tunnel study investigates axial induction based control concepts. It is examined how the total array efficiency of two in-line model turbines is affected when the upstream turbine's tip speed ratio (λcontrol) or blade pitch angle (β-control) is modified. The focus is particularly directed on how the wake flow behind the upstream rotor is affected when its axial induction is reduced in order to leave more kinetic energy in the wake to be recovered by a downstream turbine. It is shown that the radial distribution of kinetic energy in the wake area can be controlled by modifying the upstream turbine's tip speed ratio. By pitching out the upstream turbine's blades, however, the available kinetic energy in the wake is increased at an equal rate over the entire blade span. Furthermore, the total array efficiency of the two turbine setup is mapped depending on the upstream turbines tip speed ratio and pitch angle. For a small turbine separation distance of x/D=3 the downstream turbine is able to recover the major part of the power lost on the upstream turbine. However, no significant increase in the two-turbine array efficiency is achieved by altering the upstream turbine's operation point away from its optimum.

Journal Article
TL;DR: In this paper, a rotor blade modification is a blade combination where the circle-shaped conventional model is combined with the one of a concave elliptical model, which will not affect the simplicity of construction and cost of turbine rotors.
Abstract: – Many modifications have been made on c onventional Savonius wind turbine’s rotor blades have been made to improve the performances. The rotor blade modification in this research is a blade combination where the circle-shaped conventional model is combined with the one of a concave elliptical model. The combined blade will not affect the simplicity of construction and cost of manufacture of turbine rotors. The aim is to analyze the influence of the blade combination towards the performance of Savonius turbine. The research includes experimental method using open-jet-type wind tunnel of rotor’s prototype with three different blade models of the same dimension. The experiment shows, there are influences of the modification of the rotor blade to the performances of the turbine. The combined blade improves the performances of the power coefficient maximum (Cp max ) up to 11 % compared to the conventional blade at the tip speed ratio (TSR) of 0.79 Keywords - Savonius turbine, combined blade, experimental, performance


Proceedings ArticleDOI
06 Jul 2016
TL;DR: This paper compares two different wind turbine control methodologies to provide active power control (APC) ancillary services, which include derating or curtailing power generation, providing automatic generation control (AGC), and providing primary frequency control (PFC).
Abstract: As wind energy generation becomes more prevalent in some regions, there is increased demand for wind power plants to provide ancillary services, which are essential for grid reliability. This paper compares two different wind turbine control methodologies to provide active power control (APC) ancillary services, which include derating or curtailing power generation, providing automatic generation control (AGC), and providing primary frequency control (PFC). The torque APC controller provides all power control through the power electronics whereas the pitch APC controller uses the blade pitch actuators as the primary means of power control. These controllers are simulated under various wind conditions with different derating set points and AGC participation levels. The metrics used to compare their performance are the damage equivalent loads (DELs) induced on the structural components and AGC performance metrics, which are used to determine the payments for AGC services by system operators in the United States. The simulation results show that derating the turbine reduces structural loads for both control methods, with the APC pitch control providing larger reductions in DELs, lower AGC performance scores, and higher root-mean-square pitch rates. Providing AGC increases the structural loads when compared to only derating the turbine, but even the AGC DELs are generally lower than those of the baseline control system. The torque APC control methodology also allows for more sustained PFC responses under certain derating conditions.

Journal ArticleDOI
TL;DR: In this article, a variable pitch Darrieus-type wind turbine has been proposed that can reduce both the blades oscillating motion and the magnitude of angle of attack in one revolution compared to that of the fixed pitch turbines.
Abstract: Unlike horizontal axis turbines, the Darrieus-type wind turbines have less efficiency and suffer from the self-starting inability. The effects of fixed and variable blade pitch angle as an idea for improving the performance of Darrieus turbine have been investigated using the CFD analysis, and a pitching system (variable pitch Darrieus-type wind turbine) has been proposed that can reduce both the blades oscillating motion and the magnitude of angle of attack in one revolution compared to that of the Darrieus-type wind turbines. In this study, the method of computational fluid dynamics with moving mesh has been used for analyzing the unsteady two-dimensional flow simulation. The numerical results show that the SST k-ω turbulence model matches well with the experimental results and can capture the flow separation phenomenon at low tip speed ratios. Also, it was observed that a small negative fixed pitch angle of −3° can delay the separation and improve the performance of wind turbine. The numerical simulation also showed that the variable-pitch blade turbine can reduce or eliminate the flow separation on its blades at a lower tip speed ratios than that of the fixed pitch blades. This result increases the starting torque and obtaining high efficiency with decreasing in torque ripple on blades during the turbine operation compared to that of the fixed-pitch blade Darrieus turbine.

Journal ArticleDOI
TL;DR: In this paper, the effect of pitch angle on the performance of a horizontal axis wind turbine was investigated using a commercial CFD code Fluent, where a frozen rotor model is used for simulation, wherein the governing equations are solved in the moving frame of reference rotating with the rotor speed.

Journal ArticleDOI
01 May 2016-Energy
TL;DR: In this article, an experimental investigation of a scale-model three-bladed HATT turbine operating under different wave-current combinations was carried out in the recirculating water channel at the University of Liverpool with a paddle wavemaker installed upstream of the working section to induce surface waves travelling in the same direction as the current.

Journal ArticleDOI
TL;DR: In this paper, a robust optimization strategy for the aerodynamic design of horizontal axis wind turbine rotors including the variability of the annual energy production due to the uncertainty of the blade geometry caused by manufacturing and assembly errors is presented.
Abstract: Presented is a robust optimization strategy for the aerodynamic design of horizontal axis wind turbine rotors including the variability of the annual energy production due to the uncertainty of the blade geometry caused by manufacturing and assembly errors. The energy production of a rotor designed with the proposed robust optimization approach features lower sensitivity to stochastic geometry errors with respect to that of a rotor designed with the conventional deterministic optimization approach that ignores these errors. The geometry uncertainty is represented by normal distributions of the blade pitch angle, and the twist angle and chord of the airfoils. The aerodynamic module is a blade-element momentum theory code. Both Monte Carlo sampling and the univariate reduced quadrature technique, a novel deterministic uncertainty analysis method, are used for uncertainty propagation. The performance of the two approaches is assessed in terms of accuracy and computational speed. A two-stage multi-objective evolution-based optimization strategy is used. Results highlight that, for the considered turbine type, the sensitivity of the annual energy production to rotor geometry errors can be reduced by reducing the rotational speed and increasing the blade loading. The primary objective of the paper is to highlight how to incorporate an efficient and accurate uncertainty propagation strategy in wind turbine design. The formulation of the considered design problem does not include all the engineering constraints adopted in real turbine design, but the proposed probabilistic design strategy is fairly independent of the problem definition and can be easily extended to turbine design systems of any complexity.

Journal ArticleDOI
TL;DR: In this paper, a 3D CFD model based on Fluent is validated by corresponding experimental data and is used for the numerical simulation of the turbine performance for different setting angles under steady conditions.

Journal ArticleDOI
TL;DR: In this paper, a combination of variable rotor speed and variable blade twist was used to reduce the rotor power of a UH-60A helicopter with a forward speed of 250 km/h and a weight coefficient of 0.0065.

Journal ArticleDOI
TL;DR: In this paper, an electro-hydraulic digital pitch system is proposed to regulate output power and drive-train torque for wind turbines, which is driven by an EH-digital pitch controller.
Abstract: An electro-hydraulic digital pitch system is proposed in this paper to regulate output power and drive-train torque for wind turbines. This pitch system is driven by an electro-hydraulic digital se...

Journal ArticleDOI
TL;DR: In this article, the authors investigated the possibility of using active individual blade pitch control for positioning moored ocean current turbines within an array and showed that harmonic blade oscillations with amplitudes of 1.5° can be used to displace an ocean current turbine laterally by a distance equal to one rotor diameter when the mooring cable length is approximately 30 times the diameter of the rotor blade.

Journal ArticleDOI
TL;DR: In this paper, the performance of a small-scale vertical-axis wind turbine using dynamic blade pitching was investigated, and it was shown that the turbine efficiency is a strong function of the pitch amplitude.
Abstract: This paper describes the systematic experimental and computational studies performed to investigate the performance of a small-scale vertical-axis wind turbine using dynamic blade pitching. A vertical-axis wind turbine prototype with a simplified blade pitch mechanism was designed, built, and tested in the wind tunnel to understand the role of pitch kinematics in turbine aerodynamic efficiency. A computational fluid dynamics model was developed, and the model predictions correlated well with test data. Both experimental and computational fluid dynamics studies showed that the turbine efficiency is a strong function of blade pitching amplitude, with the highest efficiency occurring around ±20 to ±25 deg amplitude. The optimum tip-speed ratio depends on the blade pitch kinematics, and it decreases with increasing pitch amplitude for the symmetric blade pitching case. A computational fluid dynamics analysis showed that the blade extracted all the power in the frontal half of the circular trajectory; however...

Journal ArticleDOI
TL;DR: In this paper, a physics-based dynamic model of a twin-spool turboshaft engine that drives a variable pitch propeller is developed, where the dynamics of the engine are defined to be the two spool speeds and the control inputs are defined as the fuel flow rate and the propeller pitch angle.
Abstract: A physics-based dynamic model of a twin-spool turboshaft engine that drives a variable pitch propeller is developed. The primary purpose for the development of this model is for researchers to use it to develop new engine control algorithms and study/predict off-design transient responses of gas turbine propulsion systems. In this model, the dynamics of the engine are defined to be the two spool speeds, and the control inputs are defined to be the fuel flow rate and the propeller pitch angle. Mockups of the turboshaft engine and the variable pitch propeller are developed using CAD software, and based on the mockups, a test stand for gas turbine engine static tests is developed. Experimental results are used to verify the dynamic model of the JetCat SPT5 turboshaft engine with a variable pitch propeller mounted on it. Based on experimental data, realistic performance maps of the engine components, including the high-pressure compressor, high- and low-pressure turbines, and variable pitch propeller are cons...