Showing papers on "Blade pitch published in 2022"

Discussion of Wind Turbine Performance Based on SCADA Data and Multiple Test Case Analysis

Abstract: This work is devoted to the formulation of innovative SCADA-based methods for wind turbine performance analysis and interpretation. The work is organized as an academia–industry collaboration: three test cases are analyzed, two with hydraulic pitch control (Vestas V90 and V100) and one with electric pitch control (Senvion MM92). The investigation is based on the method of bins, on a polynomial regression applied to operation curves that have never been analyzed in detail in the literature before, and on correlation and causality analysis. A key point is the analysis of measurement channels related to the blade pitch control and to the rotor: pitch manifold pressure, pitch piston traveled distance and tower vibrations for the hydraulic pitch wind turbines, and blade pitch current for the electric pitch wind turbines. The main result of this study is that cases of noticeable under-performance are observed for the hydraulic pitch wind turbines, which are associated with pitch pressure decrease in time for one case and to suspected rotor unbalance for another case. On the other way round, the behavior of the rotational speed and blade pitch curves is homogeneous and stable for the wind turbines electrically controlled. Summarizing, the evidence collected in this work identifies the hydraulic pitch as a sensible component of the wind turbine that should be monitored cautiously because it is likely associated with performance decline with age.

Nonlinear Control Strategies for Enhancing the Performance of DFIG-Based WECS under a Real Wind Profile

Abstract: Wind speed variations affect the performance of the wind energy conversion systems (WECSs) negatively. This paper addressed an advanced law of the backstepping controller (ABC) for enhancing the integration of doubly fed induction generator (DFIG)-based grid-connected WECS under wind range of wind speed. This enhancement was achieved through three control schemes, which were blade pitch control, rotor-side control, and grid-side control. The blade pitch control was presented to adjust the wind turbine speed when the wind speed exceeds its rated value. In addition, the rotor and grid-side converter controllers were presented for improving the direct current link voltage profile and achieving maximum power point tracking (MPPT) under speed variations, respectively. To evaluate the effectiveness of the proposed ABC control, a comparison between PI and sliding-mode control (SMC) was presented, considering the parameters of a 1.5 MW DFIG wind turbine in the Assilah zone in Morocco. Moreover, some changes in the DFIG parameters were introduced to investigate the robustness of the proposed controller under parameter uncertainties. Simulation results showed the capability of the proposed ABC controller to enhance the performance of the DFIG-WECS based on variable speed and variable pitch turbine, at both below and above-rated speed, leading to an error around 10−3 (p.u), with an ATE = 0.4194 in the partial load region; in terms of blade pitch control, an error of 2.10−4 (p.u) was obtained, and the DC-link voltage profile showed a measured performance of 5 V and remarkable THD value reduction compared to other techniques, with a measured THD value of 2.03%, 1.67%, and 1.46% respectively, in hyposynchronous, hypersynchronous, and pitch activation modes of operation. All simulations were performed using MATLAB/SIMULINK based on real wind profiles in order to make an exhaustive analysis with realistic operating conditions and parameters.

Experimental Testing of a Preview-Enabled Model Predictive Controller for Blade Pitch Control of Wind Turbines

Abstract: Model predictive control (MPC) is a control method that involves determining the input to a dynamical system as the solution to an optimization problem that is solved online. In the wind turbine research literature, MPC has received considerable attention for its ability to handle both actuator constraints and preview disturbance information about the oncoming wind, which can be provided by a lidar scanner. However, while many studies simulate the wind turbine response under MPC, very few physical tests have been carried out, likely due in part to the difficulties associated with solving the MPC problem in real time. In this work, we implement MPC on an experimental, scaled wind turbine operating in a wind tunnel testbed, using an active grid to create reproducible wind sequences and a hot-wire anemometer to generate upstream wind measurements. To our knowledge, this work presents the first physical test of MPC for blade pitch control of a scaled wind turbine. We compare two MPC strategies: one including preview disturbance information and one without. Our results provide further evidence that feedforward control can improve wind turbine performance in transition and above-rated conditions without increasing actuation requirements, which we hope will encourage industry experimentation and uptake of feedforward control methods. We also provide a high-level analysis and interpretation of the computational performance of the chosen approach. This work builds upon the results of an earlier study, which considered unconstrained optimal blade pitch control.

Fault-tolerant optimal pitch control of wind turbines using dynamic weighted parallel firefly algorithm

Abstract: With steadily increasing interest in utilizing wind turbine (WT) systems as primary electrical energy generators, fault-tolerance has been considered decisive to enhance their efficiency and reliability. In this work, an optimal fault-tolerant pitch control (FTPC) strategy is addressed to adjust the pitch angle of WT blades in the presence of sensor, actuator, and system faults. The proposed scheme incorporates a fractional-calculus based extended memory (EM) of pitch angles along with a fractional-order proportional-integral-derivative (FOPID) controller to enhance the performance of the WT. A dynamic weighted parallel firefly algorithm (DWPFA) is also proposed to tune the controller parameters. The efficiency of the proposed algorithm is evaluated on the test functions adopted from 2017 IEEE congress on evolutionary computation (CEC2017). The merits of the proposed fault-tolerant approach are tested on a 4.8-MW WT benchmark model and compared to conventional PI and optimal FOPID approaches. Corresponding comparative simulation results validate the effectiveness and fault-tolerant capability of the proposed control paradigm, where it is observed that the proposed control scheme tends to be more consistent in the power generated at a given wind speed.

Multivariable Model-Free Adaptive Controller Design With Differential Characteristic for Load Reduction of Wind Turbines

Abstract: The asymmetric loads on wind turbines are becoming a fatal constraint factor with the increase of wind turbine size. In order to tackle this challenge, individual pitch control mechanism is introduced into the wind turbines. However, the application scopeof the traditional individual pitch control (IPC) is limited due to the complex dynamic coupling among wind turbine components, the strong nonlinearity of the pitch system and the inevitable unmodeled dynamics. Therefore, a multivariable model-free adaptive control (MIMO-DE-MFAC) strategy with differential characteristic is first proposed in this paper. Then, the proposed method is applied to the individual pitch control of the 5MW wind turbine. The simulation results from FAST demonstrate that the MIMO-DE-MFAC achieves a notable performance improvement on blade root compared with the PI. Furthermore, compared with other existing model-free adaptive control (MFAC) strategies, the proposed method not only achieves the optimal control results, but also has stronger robustness in speed-varying wind fields. Finally, the hardware-in-the-loop (HIL) experiment further verifies the reliability of the above simulation results, which provides a useful reference value for the field test.

Optimization procedures for a twin controllable pitch propeller of a ROPAX ship at minimum fuel consumption

Abstract: A propeller optimization procedure is developed by coupling a propeller design tool with a nonlinear optimizer. An optimized propeller contributes toward maritime decarbonization and the mitigation of exhaust emissions from ships. The main objective of this optimization procedure is to select two ducted controllable pitch propellers from the Kaplan 19A series at the service speed for a roll-on/roll-off passenger ship sailing in calm water as a case study. The selected ship is operated by two four-stroke marine diesel engines, each connected to a controllable pitch propeller via a gearbox and a propeller shaft. The propeller selection is performed at the engine operating point with minimum fuel consumption instead of considering only the maximum propeller efficiency. The propeller diameter, pitch, expanded area ratio and rotation speed are optimized as well as the gearbox ratio taking into account the limitations of noise and cavitation criteria. The calculated results from each simulation are compared with the typical procedure used in ship design, which is the selection of the propeller at maximum efficiency. The results show that optimizing the propeller in terms of fuel consumption can reduce the amount of fuel consumed by up to 5.2% rather than only considering the propeller efficiency.

A New combined MPPT-Pitch Angle control of a Large Variable Speed Wind Turbine in Different Operating Areas based on Synergetic control

Abstract: The aim of this paper is to create a novel combination between two controls, maximum power point tracking (MPPT) and Pitch angle control system of a variable-speed wind turbine. The main objective sought is to achieve the maximization of the power produced by the fixed pitch angle turbine through the MPPT control in the zone 02 of operation. Then, limit the power to its nominal value by using the Pitch control with variable pitch angle in zone 03 of operation. Our contribution will be to propose strategies based on two types of controllers. The first is the control by the MPPT control, it is applied in light winds to extract the maximum power. The second is Variable Pitch Control, which is applied in strong winds to keep power constant at its nominal value, as well as protecting the wind turbine from high winds. For this, linear and non-linear control laws (PI, SC) respectively are implemented to achieve the defined objective. The simulation results show the feasibility and effectiveness of the techniques used.

Effect of pitching motion on production in a OFWT

Abstract: Abstract The performance of offshore floating wind turbines (OFWTs) is affected by the movement along the 6 Degrees of Freedom (DOFs), which is caused by the combined influence of wind and waves. Particularly, interesting is the pitching motion, which can lead to significant changes in aerodynamic and net generated power. This paper analyzes the influence of pitching motion on the net generated power, considering for the first time in literature the OFWT control systems (blade pitch and generator controller). An in-house model based on the Blade Element Momentum (BEM) theory is used, in which sinusoidal pitch movements characterized by different values of amplitude, frequency and offset are imposed. In this way, it is possible to evaluate the influence of these three parameters on the extracted power at different values of wind speed. Results identify in the pitch amplitude and frequency the most significant variables for variations in OFWT power output, and that the influence of pitch oscillation on the average extracted power considerably varies at different wind conditions.

Handling Individual Pitch Control within an Actuator Disk framework: verification against the Actuator Line method and application to wake interaction problems

Abstract: The present study aims at assessing the Actuator Disk (AD) method supplemented with an Individual Pitch Control (IPC) strategy, at a resolution appropriate for the Large Eddy Simulation of large wind farms. The IPC scheme is based on a state-of-the art individual pitch control, generalized to be applied to an AD approach. This procedure also requires an accurate recovery of the flapwise bending moment on each blade, which is not trivial for a disk-type model. In order to compute flapwise moments on each blade, blade trajectories are reproduced through the disk and the AD aerodynamic forces are interpolated onto these virtual blades at each time step. We verify the AD model with IPC in simulations of an isolated wind turbine, for different wind speeds and turbulence intensities, and in a configuration with two rotors. We compare the AD statistics with those obtained using an Actuator Line (AL) method. The comparison done in terms of equivalent moment shows that the AD and AL simulations produce very similar results.

A Comparative Analysis of the Characteristics of Platform Motion of a Floating Offshore Wind Turbine Based on Pitch Controllers

Abstract: The installation of fixed offshore wind power systems at greater water depths requires a floating body at the foundation of the system. However, this presents various issues. This study analyzes the characteristics of the platform motion of a floating offshore wind turbine system based on the performance of the pitch controller. The motion characteristics of the platform in a floating offshore wind power generation system, change according to the response speed of the blade pitch controller since the wind turbine is installed on a floating platform unlike the existing onshore wind power generation system. Therefore, this study analyzes the platform motion characteristics of a floating offshore wind turbine system using various pitch controllers that have been applied in previous studies. Consequently, an appropriate pitch controller is proposed for the floating offshore wind turbine system. The floating offshore wind turbine system developed in this study consists of an NREL 5-MW class wind turbine and an OC4 semi-submersible floating platform; the pitch controller is evaluated using FAST-v8 developed by NREL. The results of this study demonstrate that the pitch controller reduces the platform motion of the floating offshore wind power generation system, considering both the individual pitch control and the negative damping phenomenon. Additionally, it is confirmed that the output increases by approximately 0.42%, while the output variability decreases by 19.3% through the reduction of the platform movement.

CFD Simulation of Co-Planar Multi-Rotor Wind Turbine Aerodynamic Performance Based on ALM Method

Abstract: Considering requirements such as enhanced unit capacity, the geometric size of wind turbine blades has been increasing; this, in turn, results in a rapid increase in manufacturing costs. To this end, in this paper, we examine the aerodynamics of co-planar multi-rotor wind turbines to achieve higher unit capacity at a lower blade length. The multiple wind rotors are in the same plane with no overlaps. The ALM-LES method is used to investigate the interaction effect of the blade tip vortices, by revealing the regulation of aerodynamic performance and flow field characteristics of the multi-rotor wind turbines. The simulated results suggest an observable reduction in the blade tip vortices generated by blades located closely together, due to the breaking and absorption of the blade tip vortices by the two rotors. This results in increased aerodynamic performance and loads on the multi-rotor wind turbine. The influence between the blade tip vortex is mainly located in the range of 0.2 R from the blade tip, with this range leading to a significant increase in the lift coefficient. Thus, when the wind rotor spacing is 0.2 R, the interaction between the blade tip vortices is low.

Reduction and analysis of rotor blade misalignments on a model wind turbine

Abstract: Model wind turbines with rotor diameters below 1 m often make use of a collective pitch control instead of an individual pitch control. As a result it is more difficult to achieve a high precision in the rotor blade pitch angle, especially when it comes to achieving the same pitch angle on each rotor blade. For the Model Wind Turbine Oldenburg 0.6 (MoWiTO 0.6) a rotor blade misalignment between the individual blades of up to 2.5 degrees was found. Due to the design, similar blade misalignments could also occur at other model wind turbines with a collective pitch mechanism. Here, it is shown that even small rotor blade misalignments influence the experimental results of small model wind turbines and should be avoided. In addition, a new mounting procedure is presented that serves to minimize blade misalignments when assembling the individual rotor blades in the manufacturing process. This procedure makes use of 3D printed parts that enclose the rotor blade during the mounting process and guarantee a precise pitch angle. The presented procedure is easily applicable to other model wind turbines as well. The subsequent experimental investigations of blade misalignments in the range of ±2.5 degrees show a significant influence on the turbine performance and thrust. A blade misalignment of +2.4 degrees for only one blade already decreases the mean power output of the turbine by up to 9%. Additionally, the mean thrust measurements show a clear influence of the blade misalignment (up to 17% difference) in comparison to the optimal pitch reference case. Furthermore the 1P (one-per-revolution) peaks of the thrust spectrum are significantly increased with present blade misalignments which suggests cyclic loads. These results underline the relevance of a precise rotor blade attachment for model wind turbines used in wind tunnel experiments.

Numerical and experimental analysis on the helicopter rotor dynamic load controlled by the actively trailing edge flap

Abstract: Abstract Reducing the rotor dynamic load is an important issue to improve the performance and reliability of a helicopter. The control mechanism of the actively controlled flap (ACF) on the rotor dynamic load is numerically and experimentally investigated by a 3-blade helicopter rotor in this paper. In the aero-elastic numerical approach, the complex motion of the rotor such as the stretching, bending, torsion and pitching of the blade including the deflection of the ACF are all taken into consideration in the structural formulation. The aerodynamic solution adopted the vortex lattice method combined with the free wake model, in which the influence of ACF on the free wake and the aerodynamic load on the blade is taken into account as well. While the experimental method of measuring hub loads and acoustic was accomplished by a rotor rig in a wind tunnel. The result shows that the 3/rev ACF actuation can reduce the 3 ω hub load by more than 50% at maximum, which is significantly better than the 4/rev control. While 4/rev has greater potential to reduce blade vortex interaction (BVI) loads than 3/rev with µ = 0.15. Further mechanistic analysis shows that by changing the phase difference between the dynamic load on the flap and the rest of the blade, the peak load on the whole blade can be improved, thus achieving effective control of the hub dynamic load, the flap reaches the minimum angle of attack at 90 ∘ –100 ∘ azimuth under best control condition; when the BVI load is perfectly controlled, the flap reaches the minimum angle of attack at 140 ∘ azimuth, and by changing the circulation of the wake, the intensity of BVI in the advancing side is improved. Moreover, an interesting finding in the optimal control of noise and vibration is that an overlap point exists on the motion patterns of the flap with different frequencies.

Wind tunnel investigation of the aerodynamic response of two 15 MW floating wind turbines

Abstract: Abstract. The aerodynamics of floating turbines is complicated by large motions which are permitted by the floating foundation, and the interaction between turbine, wind, and wake is not yet fully understood. The object of this paper is a wind tunnel campaign finalized at characterizing the aerodynamic response of a 1:100 scale model of the IEA 15 MW subjected to imposed platform motion. The turbine aerodynamic response is studied focusing on thrust force, torque, and wake at 2.3D downwind the rotor. Harmonic motion is imposed in the surge, sway, roll, pitch, and yaw directions with several frequencies and amplitudes, which are selected to be representative of the two 15 MW floating turbines developed within the COREWIND project. Thrust and torque show large-amplitude oscillations with surge and pitch motion, the main effect of which is an apparent wind speed; oscillations in thrust and torque are negligible with the other motions, the main effect of which is to alter the wind direction. The thrust and torque response measured in the experiment is compared with predictions of a quasi-steady model, often used for control-related tasks. The agreement is good in the case of low-frequency surge motion, but some differences are seen in the pitch case. The quasi-steady model is not predictive for the response to wave-frequency motion, where blade unsteadiness may take place. Wake was measured imposing motion in five directions with frequency equal to the wave frequency. The axial speed is slightly lower with motion compared to the fixed case. The turbulence kinetic energy is slightly lower too. Wave-frequency motion seems to produce a more stable and lower flow mixing.

Wells Turbine as a Power Take-Off Mechanism for Wave Energy Converters

Abstract: Wells turbine is an axial flow bi-directional turbine used for wave energy conversion by Oscillating Water Column (OWC) system. Different variations of Wells turbine have been studied and tested to find out the best rotor geometry. A comprehensive review of Wells turbine is presented here to familiarize the reader with the state of the art of Wells turbine. Turbines are broadly classified into two types: monoplane and biplane, with further classifications including attachment of guide vanes and variation of blade pitch angles. Numerical optimization works carried out on air turbines for wave energy system are also presented in this chapter. Turbines with optimized geometry give a better performance compared to standard turbines in terms of overall system performance, efficiency, and energy absorption.

Control of the rated production power of DFIG-wind turbine using adaptive PSO and PI conventional controllers

Abstract: Production of rated power and protection of generator and power converter from an overload are necessary. Therefore, measuring the accurate value of the pitch angle of the doubly fed induction generator (DFIG) wind turbine is essential. An assessment study between the adaptive particle swarm optimisation (PSO) technique and conventional proportional integral (PI) controller of the pitch control system in limiting the electrical output power at the rated value of DFIG is introduced in this study. Pitch control with PSO is designed by solving the nonlinear equation of pitch angle at each wind speed higher than rated wind speed. The PI controller gains of the pitch system are evaluated to keep the power limited at rated value. Accuracy in measuring pitch angle is essential because a small difference in pitch angle value results in an overload on the generator. The performance of each parameter of DFIG with a detailed analysis is studied. The simulation shows that the pitch control system with PSO technique gives better results in regulating the DFIG output power compared to PI controller method under wind speed variation.

Development of Pitch Angle Control Algorithm for PMSG Based Wind Energy Conversion System

Abstract: An efficient control system is required to operate various components of the wind energy conversion system smoothly. One of the most significant elements for the proper operation of wind turbine blades is the pitch angle control system. This paper has developed a pitch angle controlling algorithm for vertical axis wind turbines, and its performance is evaluated in a simulated environment using MATLAB/Simulink software. The effect of pitch angle variations on power production has been investigated. When the wind speed crosses the limited value of the rated power, the pitch control algorithm steps in and adjusts the blade pitch angle (beta) by an appropriate increment, allowing the power output to remain within the rated amount. The proposed system has a rated output power of 1 kW, consisting of a permanent magnet synchronous generator, a vertical-axis wind turbine incorporated with a pitch controller, and an MPPT-controlled boost converter.