Torque Of Wind Turbine Research Articles

Computational Fluids Dynamics Performances Analysis of Ramie-Albizia Composited for Wind Turbine Rotor

Computational Fluids Dynamics was performed to simulate the performance of torque and output power of wind turbine. Propeller of wind turbine is made by sandwich composite. The composite is combination of ramie fiber with Albizia wood as a core. FLUENT is used to perform simulation of propeller at different wind speeds. The wind speeds ranges from 3 to 5 m/s at coastal area of Kwaru, Bantul, Yogyakarta. Spallart-Almaras method uses to simulate the torque and power output at different Reynold Number. The simulation result shows that the torque of rotor ranges from 25 to 75 Nm, power outputs range from 50 to 240 W and power output coefficients are lay between 0.35 to 0.40 for wind speed from 3 to 5 m/s which is typical in coastal area of Indonesia.

Voltage and Reactive Power Control of Front-end Speed Controlled Wind Turbine via H∞ Strategy

According to the characteristics like rapidity, time variability and the uncertainty of the input mechanical torque of the front-end speed control wind turbine (FSCWT) with directly grid-connected electrically excited synchronous generator (EESG), a double-loop H ∞ control approach was proposed. In which, a simpilified structure of brushless excitation system was used. For the inner loop, first H ∞ excitation controller was designed for realizing a fast excitation control; the second H ∞ power system stabilizer (PSS) was designed by solving the Riccati equation for the purpose of eliminating the oscillation and desynchronization of generator may caused by fast excitation and improving the system transient stability, which ensured the generator with stable operation in grid-connecting and effectively solved the contradiction between fast excitation and transient stability. Then the designed H ∞ controllers were applied to the voltage and reactive power control system (VRCS), which realized the output voltage and reactive power control requriements by tuning the weighting functions. Simulation results show that the double-loop H ∞ control approach was more effective than the single H ∞ excitation control in voltage and reactive power control of FSCWT. DOI: http://dx.doi.org/10.11591/telkomnika.v11i8.2423

Combined Feedback–Feedforward Control of Wind Turbines Using State-Constrained Model Predictive Control

An application of model predictive control (MPC) to the wind turbine collective pitch and torque control problem in full-load operation is presented. The applied controller is able to include upstream wind speed information, e.g., from light detection and ranging measurements. Furthermore, a method is presented to include constraints on the turbine states in the problem formulation, such as on rotor speed, even in the presence of unmeasured disturbances. In a simulation study, the effects of both preview control and state constraints are evaluated for three different scenarios: normal operation, gusts, and grid-loss load cases. It is found that preview control provides significant benefits in normal operation and under gust conditions. It is further found that including state constraints in the MPC formulation can be used to avoid unnecessary shutdowns due to the violation of the overspeed limit or to control the turbine effectively when the turbine needs to run at a reduced level of generator torque.

Reduction of Wind Turbine Torque Fluctuation Using Individual Pitch Control Based on Edgewise Moment

In order to eliminate the nonuniform force on the wind rotor caused by wind shear, tower shadow and turbulence and smooth the torque fluctuation of the wind turbine and the unbalanced loads on the wind turbine, a new individual pitch control strategy based on edgewise moment using single neuron PID controller is proposed. That is, the presented control strategy directly controls the blade edgewise moment generated by aerodynamic force. At the same time, to simulate the wind turbine loads, a dynamic model of three-bladed upwind horizontal axis wind turbine is built. Thus, the influence rules of the wind turbine torque fluctuation are deduced at length. Finally, to verify the effectiveness of the proposed individual pitch control system with the single neuron PID controller, the 2MW wind turbine generator system is modeled and simulated. The performance of the controller is illustrated its capability of not only reducing the wind turbine fluctuation, but also smoothing the fluctuation of the flapwise moment, the yaw moment and the tilt moment.

Open-loop frequency response analysis of a wind turbine using a high-order linear aeroelastic model

Wind turbine controllers are commonly designed on the basis of low-order linear models to capture the aeroelastic wind turbine response due to control actions and disturbances. This paper characterizes the aeroelastic wind turbine dynamics that influence the open-loop frequency response from generator torque and collective pitch control actions of a modern non-floating wind turbine based on a high-order linear model. The model is a linearization of a geometrically non-linear finite beam element model coupled with an unsteady blade element momentum model of aerodynamic forces including effects of shed vorticity and dynamic stall. The main findings are that the lowest collective flap modes have limited influence on the response from generator torque to generator speed, due to large aerodynamic damping. The transfer function from collective pitch to generator speed is affected by two non-minimum phase zeros below the frequency of the first drivetrain mode. To correctly predict the non-minimum phase zeros, it is essential to include lateral tower and blade flap degrees of freedom. Copyright © 2013 John Wiley & Sons, Ltd.

1204 マイクロ・オウバル風車の特性実験と音計測

1204 マイクロ・オウバル風車の特性実験と音計測

Different Strategies for Controlling Output Power Smoothing of a PMSG-Based Wind Energy Conversion Systems

Abstract This paper deals with controlling the output power smoothing of a wind energy conversion systems (WECS) by using permanent magnet synchronous generator (PMSG). It uses the inertia control of the wind turbine and DC-link voltage control. The PMSG is connected to the grid through a generator-side converter and a grid-side inverter based on AC-DC-AC methods. The generator-side converter is used to control the torque of the PMSG while the grid-side inverter is used to control DC-Link voltage and grid voltage. Fuzzy logic is implemented to determine the torque command by using inertia of wind turbine. The inputs of the fuzzy logic are given by the operating point of the rotational speed of the PMSG and the difference between the wind turbine torque and the generator torque. From the proposed method, the generator torque is smoothed and kinetic energy generated by the inertia of the wind turbine is used to smooth the power fluctuations of PMSG. Also, a stable operation of WECS is achieved during the system fault by using the chopper circuit in the DC-link circuit. The output power smoothing is achieved with stability and low cost. The effectiveness of the proposed method is verified by the numerical simulations.

Scaled ice accretion experiments on a rotating wind turbine blade

This work presents ice accretion tests of a model wind turbine blade mounted on a rotor test stand. The model test blade was scaled to reproduce local flow and icing conditions at the 95% radial station of the NREL Phase VI Rotor. A modified Ruff scaling method was implemented to scale atmospheric icing conditions that could be generated in a laboratory facility. Scaling laws allowed for reduced testing time as well as a reduced chord length of the blades compared to on-site icing events were implemented. Classical Blade Element Momentum Theory (BEMT) was utilized to correlate inflow conditions at the test facility to actual operating conditions of the NREL Phase VI Rotor. Experimentally obtained rime ice shapes are compared to LEWICE predictions and are used to validate the capability of the facility to reproduce representative icing conditions. The rime ice results matched with predictions to within 1% of both ice thickness and ice extent along the blade surfaces. The effects of angle-of-attack, temperature, liquid water content, and icing time on the final ice shapes were investigated in a parametric study. Experimentally obtained glaze ice shapes are used to demonstrate the severity of the icing events on wind turbine torque. The present work comprises testing procedures and experimental data that can be used for future efforts in ice accretion modeling and testing.

최적 주속비 구간에서 로터속도 비선형 파라미터를 이용한 풍력터빈의 토크제어

Aerodynamic torque of wind turbine has nonlinear properties. Nonlinearity of aerodynamic torque is very important in wind turbine in the aspect of control. The traditional torque control method using optimal mode gain has been applied in many wind turbines but its response is slower as wind turbine size is larger. In this paper, a torque control method using a nonlinear parameter of rotor speed among nonlinear properties of aerodynamic torque. Simulink model is implemented to obtain the nonlinear parameter of rotor speed and numerical simulations for a 2MW wind turbine are carried out and simulation results for the traditional and proposed torque control methods are compared.

A Fuzzy-Logic Based Output Power Smoothing Method of WECS with Permanent Magnet Synchronous Generator using Inertia of Wind Turbine

This paper presents a fuzzy-logic-based output power smoothing method of a wind energy conversion system (WECS) with a permanent magnet synchronous generator (PMSG) using the inertia of wind turbine. The generator-side converter controls the generator torque of the PMSG, while the grid-side inverter controls the DC-link and grid voltages, respectively. For the generator-side converter, the torque command is determined by using the fuzzy logic. Inputs the fuzzy logic are the operating point of the rotational speed of the PMSG and the difference between the wind turbine torque and t he generator torque. By means of the proposed method, the generator torque can be smoothed and the kinetic energy stored by the inertia of the wind turbine can be utilized to smooth the power fluctuations of the PMSG, and the wind turbine's shaft stress is mitigated compared to a conventional maximum power point tracking (MPPT) control. Effectiveness of the proposed method is verified by the numerical simulations.

가변속도-가변피치 풍력터빈의 공기역학적 토크의 비선형 특성에 관한 고찰

Aerodynamic torque of wind turbine is highly nonlinear due to the nonlinear interactions between wind and blade. The aerodynamic nonlinearity is represented by nonlinear power and torque coefficients which are functions of wind speed, rotational speed of rotor, and pitch angle of blade. It is essential from the viewpoint of understanding and analysis of dynamic characteristics for wind turbine to linearize the aerodynamic torque and define aerodynamic nonlinear parameters as derivatives of aerodynamic torque with respect to the three parameters. In this paper, a linearization method of the aerodynamic torque from power coefficient is presented through differentiating it by the three parameters. And steady-state values of three aerodynamic nonlinear parameters according to wind speed are obtained and their nonlinear characteristics are investigated.

풍력터빈의 피치 PI 제어기 특성 고찰

블레이드와 바람의 상호작용에 의해 발생하는 풍력터빈의 공기역학적 토크와 파워의 특성은 매우 비선형적이다. 그러므로 풍력터빈의 전체 동적 거동은 풍속의 크기에 따라서 비선형적인 특성을 가진다. 공기역학적 비선형성은 또한 풍력터빈 제어시스템의 특성에 영향을 미치므로, 풍력터빈 제어기를 설계하기 위해서는 비선형적인 공기역학적 특성들에 대한 해석을 통한 고찰이 필연적이다. 본 논문에서는 정격파워 이상에서 풍속 크기에 따른 비선형적인 공기역학적 특성들과 이 비선형성들이 PI 제어기를 가지는 폐루프 피치계에 미치는 영향들을 1-질량 모델의 풍력터빈에 대하여 살펴본다

Determination of fault operation dynamical constraints for the design of wind turbine DFIG drives

This paper presents an efficient design tool for the estimation of the transient electromagnetic peak torque and transient rotor over-voltages of wind turbines (WT) doubly-fed induction generators (DFIG) during severe fault conditions on the grid side. This versatile and robust tool is well adapted to the implementation in a DFIG drives CAD environment using iterative optimization procedures. In such an application, it is used to compute the dynamical constraints function during the integrated design process of the whole drive including the generator, the gearbox and the power converters. Results show that it is necessary to take into account the dynamical constraints under fault operation, during the early steps of the system design process. Another application of the tool is also illustrated in the paper: the design of the protection system (i.e. the crowbar resistance) for a given generator, a given gearbox and a given power converter.

가변속도-가변피치 풍력터빈의 정상상태 곡선 결정 방법

Aerodynamic power and torque of wind turbine are highly nonlinear and its operation mode depends on control strategies. Therefore, it is essential to define steady-state curves for the purpose of control and operation of wind turbine system. The steady-state curves of wind turbine can be defined by determining its operating points. In this paper, an algorithm to determine operating points of variable-speed variable-pitch wind turbine is presented on the basis of pitch-to-feather control strategy. And this algorithm is applied to obtain steady-state curves for an 1.5MW wind turbine.

Modeling and simulation of wind turbine Savonius rotors using artificial neural networks for estimation of the power ratio and torque

The power factor and torque of wind turbines are predicted using artificial neural networks (ANNs) based on experimental data which have been collected for seven prototype vertical Savonius rotors tested in a wind tunnel. In this research, the rotors with different configurations were located in the wind tunnel and the tests were repeated 4–6 times in order to reduce errors. Since the Reynolds number has a negligible effect on power ratio, therefore tip speed ratio (TSR) is the main input parameter to be predicted in neural network. Also, the rotor’s power factor and torque were simulated for different tip speed ratios and different blade angles. The simulated results show a strong capability for providing reasonable predictions and estimations of the maximum power of rotors and maximizing the efficiency of Savonius turbines. According to artificial neural nets simulations and the experimental results, increasing tip speed ratio leads to a higher power ratio and torque. For all the tested rotors, a maximum and minimum amount of torque has happened at angle of 60 o and 120 o, respectively.

Simulation of the aerodynamic behaviour of a micro wind turbine

In this paper the Computational Fluid Dynamics (CFD) simulation of a wind turbine with a rotor diameter of 2.2 meters is performed using the Fluent commercial code. Renewable energies are only effective if implemented in a large scale basis. Given this fact, this CFD study is part of the effort that is currently being made at the University of Beira Interior, Portugal, in order to develop a family of complete micro wind systems suitable for partial production by the final users. The target objectives of the project are to provide a quality, open source, small wind turbine project for the masses, with emphasis on low cost, reliability and ease construction. In a first phase battery charging systems are being developed, to be followed later by grid connected ones. The micro turbines being developed follow the mainstream configuration for this size class, and so are of the horizontal axis type, have three blades, a tip speed ratio of 6, constant pitch and a passive wind orientation system with side furling. The generators are of the axial flux permanent magnet type. The blades have a NACA 4415 wing section in all their span which is, at present, judged as a good compromise between performance and structural ruggedness given that it is a relatively thick profile. A 3D CAD model of the rotor was modelled with the Rhinoceros 3D program. In order to support the physical development of the wind turbine CFD simulations were performed. In this work results will be presented for turbulent flow computations around the wind turbine. The flow was computed by solving the Navier-Stokes equations with   k turbulence model. A detailed analysis of the pressure distribution for three sections along the blade span is also presented. Load distribution and boundary layer separation is studied. Finally, a series of computations are performed in order to obtain the wind turbine torque and efficiency signature as a function of rotation. The obtained results will be, in the near future, compared to fullscale field tests. These will be carried out on a mobile test rig currently under development at University of Beira Interior, Portugal.

J0503-2-5 垂直軸風車翼の空力研究(風力発電(2))

The torque of vertical axis wind turbines fluctuate periodically, because the relative wind velocity experienced by the blade varies with the azimuth angle of the rotor. The periodic torque fluctuation brings about fatigue load which causes increasing cost. The objective of this study is to clarify the torque fluctuation on blades of vertical axis wind turbines. The wind tunnel experiment was performed with actual size vertical axis wind turbine and the torque fluctuation was observed by using strain gages. In addition, the torque fluctuation was analyzed by CFD. This paper describes the comparison between the experimental results and the numerical results.

1206 直線翼垂直軸型風車のトルク変動解析(OS12-2 再生可能流体エネルギー,オーガナイズドセッション)

The rotor torque of straight-blade vertical axis wind turbines fluctuates periodically, because the relative wind velocity experienced by the blade varies with the azimuth angle of the rotor. The objective of this study is to clarify the torque fluctuation on blades of vertical axis wind turbines. The wind tunnel experiment was performed with actual size vertical axis wind turbine and the torque fluctuation was observed by using strain gages. In addition, the torque fluctuation was analyzed by CFD. This paper describes the comparison between the experimental results and the numerical results. And the relation between wind turbine design conditions and the torque fluctuation is clarified.

Wind Turbine Simulation Procedures

The main goal of this work is to develop specific procedures for implementation in wind turbine simulators designed especially for small machines. Using blade element methodology, we establish procedures for the torque and power characteristics of a small wind turbine, where some physical construction parameters are known. The algorithm is developed for two simulation procedures, which differ by the parameter used for the set of characteristics (wind speed or pitch angle).

Simulation of a Fixed Pitch Wind Turbine Powered Induction Generator in EMTP

Simulation of a fixed pitch wind turbine powered induction generator in EMTP Described are two models of a fixed pitch wind turbine drive train coupled to an induction generator compatible with the Electromagnetic Transients Program (EMTP). The models require wind speed or turbine torque changes. Model performance is studied on a 30 kW commercial arrangement.