Simulation Model Of Wind Turbine Research Articles

The impacts of atmospheric icing on performance and behavior of a controlled large-scale wind turbine

Icing degrades turbine performance by altering the geometry of blade airfoils, reducing turbine power output, and increasing structural loads. In this study, the impacts of atmospheric icing on the full performance and behavior of a controlled large-scale wind turbine are thoroughly investigated. Using the Mustafa Sahin bladed wind turbine simulation model, the National Renewable Energy Laboratory 5 MW turbine is simulated with and without iced blades. The turbine blades are considered fully covered by light icing at the leading edge, which causes a reduction of up to 9.27% in Cl and an increase of up to 48% in Cd data of blade airfoils. Turbine static performance and behavior are examined at different uniform winds between cut-in and cut-out wind speeds, while the dynamic performance and behavior are estimated under turbulent winds at below (region II) and above (region III) rated regions. Simulation results are presented in terms of various turbine parameters, such as rotor power, thrust, their coefficients, blade pitch angle, rotor speed, etc. Results show that such light icing alters the turbine's aerodynamic characteristics and dynamics, increasing the turbine's cut-in and rated wind speeds, and reducing the thrust and maximum power coefficients by 5.5% and 13.35%, respectively. Under the same uniform winds, due to icing, turbine static performance and behavior are drastically disrupted in below rated region, resulting in reduced rotor speed, turbine efficiency, thrust, and power output by up to 4.77%, 39.7%, 7.63%, and 40%, respectively. In region III, however, thrust increases by up to 15% although the power output, rotor speed, and turbine efficiency do not change considerably. When the dynamic responses are examined under turbulent wind with a mean of 7.9 m/s in region II, mean power and fluctuations reduce by 14.17% and 10.88%, respectively. The mean thrust decreases by 6.86%, while its fluctuations reduce by 11.33%. The mean rotor speed reduces by 3.83%, and its fluctuations decrease by 12.84%. Under turbulent wind with a mean of 15.7 m/s in region III, the mean power and fluctuations decrease by 0.053% and 1.95%, respectively. The mean thrust increases by 11.99% and its fluctuations drop by 0.84%. The mean rotor speed does not change much, but its fluctuations increase by 0.132%. The mean blade pitch angle reduces by 9.39%, while its fluctuations increase by 7.39%.

Fast Frequency Control Strategy for Direct Drive Wind Turbines Considering the Suppression of Secondary Frequency Drop in the Power Grid

Inertia and damping in the power system are important parameters in frequency regulation and oscillation suppression. Inertia will reduce the rate and amplitude of frequency changes after active power sudden changes. Damping in the system can effectively suppress low-frequency oscillations after grid disturbances. As the penetration rate of wind turbines increases, it will significantly reduce the effective inertia in the power grid and reduce the friendliness of wind power grid connection. To provide better frequency support for the power grid in the event of large disturbances in the power system, this paper proposes a fast frequency control strategy for wind farms that considers the suppression of secondary frequency dips in the power grid. The strategy combines frequency droop control with grid frequency bias control and evaluates the kinetic energy reserve online based on wind power prediction and hourly speed, thus balancing the frequency regulation and suppression of secondary frequency dips in the power grid. A 2.5 MW direct drive wind turbine simulation model was built based on the PSCAD simulation platform, verifying the effectiveness of the proposed comprehensive control strategy.

Effects of Atmospheric Icing on Performance of Controlled Wind Turbine

Icing deteriorates the performance of wind turbine rotors by changing the blade airfoils’ shapes. It decreases the lift, increases the drag, and subsequently causes power production losses and load increase on turbines’ structures. In the present study, the effects of atmospheric icing on the performance of a controlled large-scale wind turbine is estimated through simulations. To achieve the target, the MS (Mustafa Sahin) Bladed Wind Turbine Simulation Model is used for the analyses of the National Renewable Energy Laboratory (NREL) 5 MW turbine with and without iced blades. Icing modeling is realized based on its main characteristics and its effects on blade aerodynamics. Turbine performance estimations are carried out at various uniform wind speeds between cut-in and cut-out wind speeds and are presented in terms of various turbine parameters such as power, thrust force, blade pitch angle, and rotor speed. Simulation evaluations show that even a light ice accretion along the blades varies the turbine characteristics and dynamics, changes the cut-in and rated wind speeds, and affects the aforementioned turbine parameters differently in the below and above rated regions.

Control Strategy and Parameter Optimization Based on Grid Side Current Dynamic Change Rate for Doubly-Fed Wind Turbine High Voltage Ride Through

High voltage ride through (HVRT) control strategies for doubly-fed induction wind turbines (DFIG) have mostly focused on the rotor side converter, while the reactive power compensation capability of the grid side converter and the impact of grid side converter current transients have often been ignored on the DC bus voltage and reactive power. Therefore, a control strategy based on grid side current dynamic change characteristics is proposed, which resets the reference values of the grid side active and reactive currents for wind turbine HVRT to ensure partial absorption of reactive power on the grid side. Secondly, the key parameter in the proposed control strategy is optimization to get the most suitable DC bus voltage value with the grey wolf algorithm. Finally, the grid-integrated wind turbine simulation model is built on the MATLAB/SIMULINK and RT-Lab platforms. The simulation test results show that the proposed HVRT control strategy and its parameter optimization method are effective, DFIG can achieve HVRT when the wind turbine voltage rises to 1.3 pu.

Adaptive envelope protection control of wind turbines under varying operational conditions

This study introduces a new Envelope Protection System (EPS) algorithm for wind turbines. The algorithm is adaptive to turbine-changing operational conditions and can effectively reduce turbine excessive/ultimate loads. Through an adaptive neural network, the proposed algorithm continuously monitors instantaneous wind and turbine states. Simultaneously, it predicts the near future response of the turbine load and detects its future crossing with a predefined safe envelope limit by comparing the actual wind speed to a theoretically estimated wind speed. When required, a protection action is applied based on the comparison to keep the turbine load response within the safe limit. In this paper, the thrust force is used as the critical load and is chosen as the limit parameter. Simulations are carried out using the MS (Mustafa Sahin) Bladed Wind Turbine Simulation Model for the National Renewable Energy Laboratory (NREL) 5 MW turbine under normal turbulent winds with different mean values. Simulations show that the EPS algorithm adapts to varying operational conditions such as changes in turbine operating point in the below rated, transition, and above rated regions, as well as rotor blade icing and successfully reduces the excessive thrust forces. Performance analyses indicate that, for keeping the thrust force within the limit, the proposed EPS algorithm reduces the thrust force by 98.89%, 98.43%, 99.26% relative to standard baseline controls in the aforementioned regions, respectively and by 99.61% under blade icing. Also, the mean value and the fluctuations of thrust force are reduced up to 5.52% and 68.7%, respectively. Depending on the operating region, the mean power decreases up to 2.07% or increases up to 1.21%, while power fluctuations decrease up to 30.97%.

Small Magnus Wind Turbine: Modeling Approaches

Renewables have passed the peak of the inflated expectation hype cycle for emerging technologies, but interest in the design of new energy conversion devices is still high due to widespread distributed energy systems for private households. Magnus effect-based wind turbine combines mechanical and electronic engineering that provides a broader wind speed range and potential maximum power point tracking for deeper grid integration. This paper provides a comparative analysis of Magnus effect-based wind turbine simulation models and the development of the numerical model for the maximum power point tracking algorithm. The advanced model contributes to the reduction of the number of actual tests required for the mechatronics system tuning and deals with sustainability-related challenges, such as climate change and the development of new renewable sources of energy.

Research and application of low voltage ride through capability of wind turbines in microgrid

In order to adapt to the stable operation of microgrid operating conditions, asynchronous constant speed wind turbines need to have low voltage ride through capability. For the characteristics of a certain type of asynchronous wind turbine,the technical control of full-power back-to-back converter is proposed. The machine-side converter stabilizes the stator voltage, the grid-side converter stabilizes the DC bus voltage and controls the active and reactive decoupling. The 750 kW wind turbine simulation model is established in MATLAB/Simulink, and the rectified unit is field tested and verified to have low voltage ride through capability.

Research on the Influence of Wind Characteristics on Output Characteristics of Doubly - fed Wind Turbines

The inherent randomness and intermittence of wind power will make it difficult to accurately predict the output of wind farms and the regulation and stability of power grids. As the output power of the turbine is proportional to the third power of the wind speed, tiny variation of the wind speed will cause much larger fluctuation of the turbine output. With the construction of wind farms gradually moving to non-wind resource-rich areas such as mountainous areas, wind turbines have to face more pulsating wind and greater turbulence intensity. In this paper, based on field measurement data and Generated wind conditions, a doubley-fed wind turbine simulation model was built to simulate the influence of different wind condition variations on the output characteristics of the doubly-fed wind turbines. The response of wind turbines to pulsating wind speed is analyzed by using the step response module to simulate the characteristics of wind. By dividing three different working intervals of wind turbine, the influence of different turbulence intensity on the output characteristics of wind turbines is analyzed. The simulation results have theoretical significance for improving the accuracy of wind turbine output prediction and wind turbine optimization design.

Engineering modelling of wind turbine applied in real‐time simulation with hardware‐in‐loop and optimising control

In order to constantly improve the output characteristics of wind turbines, the HIL (Hardware In the Loop) experimental platform of wind turbines is built to optimize control. According to the product parameters of 1.5 MW direct-drive PMSG (Permanent Magnet Synchronous wind Generator) of Dongfang Electric Corporation (DEC), the simulation model of wind turbine is built in RTDS (Real Time Digital Simulator), and optimised by comparing with the wind speed–power curve of products, the simulation model of wind turbine with engineering accuracy can be obtained. Base on the engineering model and actual controller of products, the HIL experimental platform of wind turbines is built to optimise control. In the case of unbalanced or asymmetrical grid voltage, in order to make the wind turbine output be stable, the DDSOGI-PLL (direct Decoupling Double Second-Order Generalized Integral Phase-Locked Loop) is proposed to improve the performance of PLL, the active/reactive current decoupling algorithm based on positive and negative sequence voltage orientation respectively is proposed to eliminate the negative sequence current to maintain a constant output power. The effectiveness of algorithm is verified by the HIL experimental platform, the active power output of wind turbine remains constant, the grid-connected adaptability of wind turbines is improved significantly.

Observer design and optimization for model-based condition monitoring of the wind turbine rotor blades using genetic algorithm

In this paper a model based approach for condition monitoring and diagnosis of faults in the wind turbine rotor blades is described. The investigation is focused on creating a fault-free reference system, the design and optimization of the controller/observer based on the Disturbance Accommodating Control theory and the multi-objective genetic optimization algorithm in order to further enhance the condition monitoring and faults diagnosis. Test cases are presented by injecting a parameter change, e.g. pitch angle, as an error to the non-linear wind turbine simulation model in order to demonstrate that the proposed method is able to detect the fault on the blades.

Electrical Signal Analysis for Bearing Fault of Wind Turbine Based on EMD

In this paper, according to the bearing current signal is nonstationary and nonlinear characteristics, establish of doubly fed wind turbine simulation model and test bench, respectively under the normal and fault condition of bearing of motor current signal by EMD processing and analysis. Through the simulation analysis and experimental verification, it shows that after the EMD decomposition of the IMF component can effectively isolate the fault information in the current signal.EMD is an effective method of current signal processing

Sensor Fault-Tolerant Control of a Drivetrain TestRig via an Observer-Based Approach within a WindTurbine Simulation Model

This paper presents the implementation of an observer-based fault reconstructionand fault-tolerant control scheme on a rapid control prototyping system. The observer runs inparallel to a dynamic wind turbine simulation model and a speed controller, where the latter isused to control the shaft speed of a mechanical drivetrain according to the calculated rotor speedobtained from the wind turbine simulation. An incipient offset fault is added on the measuredvalue of one of the two speed sensors and is reconstructed by means of a Takagi-Sugeno sliding-mode observer. The reconstructed fault value is then subtracted from the faulty sensor valueto compensate for the fault. The whole experimental set-up corresponds to a sensor-in-the-loopsystem.

Blind Test 2 calculations for two in-line model wind turbines where the downstream turbine operates at various rotational speeds

In this paper we report on the results of the Blind Test 2 workshop, organized by Norcowe and Nowitech in Trondheim, Norway in October 2012. This workshop was arranged in order to find out how well wind turbine simulation models perform when applied to two turbines operating in line. Modelers with a suitable code were given boundary conditions of a wind tunnel test performed in the large wind tunnel facility at the Department of Energy and Process Engineering, at NTNU Trondheim, where two almost identical model turbines with a diameter of about 0.9∼m had been tested under various operating conditions. A detailed geometry specification of the models could be downloaded and the modelers were invited to submit the calculation without knowing the experimental results in advance.Nine different contributions from eight institutions were received, representing a wide range of simulation models, such as a LES coupled with an actuator line rotor model, RANS using an actuator disc, U-RANS models applied to fully resolved turbine model geometries, as well as a vortex panel method. The comparison showed a larger than expected scatter on the performance calculation of the upstream turbine (±20%), and an even higher uncertainty for the downstream turbine, especially at operating conditions close to the runaway point. The modelers were requested to document the wake development downstream of the second turbine, the development behind the first turbine had been the challenge for a previous blind test (see Krogstad and Eriksen [17]).Mean flow calculations reported at X = 1D downstream of the second turbine showed that the models which fully resolved boundary layers on the rotor surface performed best. Including the tower and the hub in the simulation improved the accuracy of the predictions and is essential in capturing the important asymmetries that develop in the wake. These turbine details strongly influence the development near the center of the wake, but are often omitted in simulations in order to incorporate simplifying symmetry conditions in the calculations. Further from the rotor, at X = 4D, the LES simulations coupled to actuator line rotor models performed well and were able to capture the main features of the mean and turbulent flows, while RANS models using actuator disc models showed limitations especially in predicting correctly the turbulent kinetic energy.

Model‐independent periodic stability analysis of wind turbines

AbstractIn this work, a new method is proposed for the stability analysis of wind turbines. The method uses input–output time histories obtained by conducting virtual excitation experiments with a suitable wind turbine simulation model. Next, a single‐input/single‐output periodic reduced model is identified from the recorded response and used for a stability analysis conducted according to the Floquet theory. Since only input–output sequences are used, the approach is model independent in the sense that it is applicable to wind turbine simulation models of arbitrary complexity. The use of the Floquet theory reveals a much richer picture than the one obtained by widespread classical approaches based on the use of the multi‐blade coordinate transformation of Coleman. In fact, it is shown here that, for each principal mode computed by the classical approach, there are in reality infinite super‐harmonics of varying strength fanning out from the principal one at multiples of the rotor speed. The relative strength of each harmonic in a fan provides for a way of measuring how periodically one specific fan of modes behaves. The notion of super‐harmonics allows one to justify the presence of peaks in the response spectra, peaks that cannot be explained by the classical time‐invariant analysis. The Campbell diagram, i.e., the plot of system frequencies vs. rotor speed, is in this work enriched by the presence of the super‐harmonics, revealing a much more complex pattern of possible resonant conditions with the per‐rev excitations than normally assumed. Copyright © 2014 John Wiley & Sons, Ltd.

High Voltage Ride through of PMSG-Based Wind Turbines

The fault ride through capability of wind turbine is becoming more important with the rapid growth of wind power installed capacity. Among several grid faults the voltage swell is a critical event. Thus, to enhance the high voltage ride through capability of popular PMSG-based wind turbine, the behavior of the PMSG wind turbine when subjected to a voltage swell was analyzed and a strategy was proposed. The overvoltage results in an increasing converter DC bus voltage. By analyzing the vector diagram of line-side converter, the paper recommends increasing inductive current assisted with chopper resistors to ride through the overvoltage safely, and the reactive current reference calculation method is given. The analysis of the performance and the strategy is presented and verified by simulations with a 1.5MW PMSG wind turbine simulation model.

타워와 블레이드의 탄성효과를 고려한 부유식 해상풍력발전기의 동적거동해석

부유식 해상풍력발전기의 시뮬레이션을 위해서 본 연구에서는 2㎿ 육상 풍력발전기에 부유구조물인 Tension Leg Platform(TLP) 구조를 추가하였다. 기상청 관측데이터와 해수면으로부터의 높이에 대해 풍속을 정의하는 지수법칙을 이용하여 풍하중을 산출하고 블레이드와 타워에 일정한 높이간격으로 적용하였다. 상대모리슨 방정식을 이용하여 파랑하중을 모델링하였다. 블레이드의 회전속도를 정격속도인 18rpm 으로 고려하고, 풍하중과 파랑하중 작용 시 2㎿ 의 부유식 해상풍력기의 동적거동 해석을 수행하였다. 파랑하중에 대한 해상풍력기의 공진특성을 조사하기 위해 타워와 블레이드의 탄성체 모델을 구성하여 해상풍력기의 고유진동수를 계산하였다. 타워와 블레이드의 탄성효과가 해상풍력기의 거동에 미치는 영향을 분석하기 위해 타워만 탄성체로 구성된 탄성타워모델과 타워와 블레이드가 탄성체로 고려된 탄성타워 블레이드모델을 각각 강체 모델과 비교하였다.

Characteristic Simulation of Wind Turbine Based on an Induction Motor

In order to better research wind power generation technology in the laboratory, this paper analyzes the characteristics of the wind turbine. Then on the basis of the analysis results, a wind turbine simulation model is built in MATLAB/SIMULINK and a simple torque imitation scheme is proposed. The program imitates the output torque characteristics of wind turbine, by controlling the induction motor torque current to control its output torque. The simulation results verify the feasibility of the wind turbine imitation program. It lays the foundation for the wind energy study.

The Use of a Code‐generating System for the Derivation of the Equations for Wind Turbine Dynamics

AbstractFor many reasons the size of wind turbines on the rapidly growing wind energy market is increasing. Relations between aeroelastic properties of these new large turbines change. Modifications of turbine designs and control concepts are also influenced by growing size. All these trends require development of computer codes for design and certification. Moreover, there is a strong desire for design optimization procedures, which require fast codes. General codes, e.g. finite element codes, normally allow such modifications and improvements of existing wind turbine models. This is done relatively easy. However, the calculation times of such codes are unfavourably long, certainly for optimization use. The use of an automatic code generating system is an alternative for relevance of the two key issues, the code and the design optimization. This technique can be used for rapid generation of codes of particular wind turbine simulation models. These ideas have been followed in the development of new versions of the wind turbine simulation code VIDYN. The equations of the simulation model were derived according to the Lagrange equation and using Mathematica®, which was directed to output the results in Fortran code format. In this way the simulation code is automatically adapted to an actual turbine model, in terms of subroutines containing the equations of motion, definitions of parameters and degrees of freedom. Since the start in 1997, these methods, constituting a systematic way of working, have been used to develop specific efficient calculation codes. The experience with this technique has been very encouraging, inspiring the continued development of new versions of the simulation code as the need has arisen, and the interest for design optimization is growing. Copyright © 2003 John Wiley & Sons, Ltd.