Low Wind Speed Areas Research Articles

Power Maximization and Control of Variable-Speed Wind Turbine System Using Extremum Seeking

Maximizing the power capture is an important issue to the turbines that are installed in low wind speed area. In this paper, we focused on the modeling and control of variable speed wind turbine that is composed of two-mass drive train, a Squirrel Cage Induction Generator (SCIG), and voltage source converter control by Space Vector Pulse Width Modulation (SPVWM). To achieve Maximum Power Point Tracking (MPPT), the reference speed to the generator is searched via Extremum Seeking Control (ESC). ESC was designed for wind turbine region II operation based on dither-modulation scheme. ESC is a model-free method that has the ability to increase the captured power in real time under turbulent wind without any requirement for wind measurements. The controller is designed in two loops. In the outer loop, ESC is used to set a desired reference speed to PI controller to regulate the speed of the generator and extract the maximum electrical power. The inner control loop is based on Indirect Field Orientation Control (IFOC) to decouple the currents. Finally, Particle Swarm Optimization (PSO) is used to obtain the optimal PI parameters. Simulation and control of the system have been accomplished using MATLAB/Simulink 2014.

Study on Optimization of Control Mechanism in Vertical Axis Wind Turbine

Objective-This paper describes an attempt to streamline the execution of the Vertical Axis Wind Turbines (VAWT) utilizing dynamic sharp edge pitch control. Methods/analysis- Aerodynamic model is chosen based on the surface profile and NACA 4-digit series was found to be the most suitable category under which NACA 0018 aerofoil design parameters have been chosen for the VAWT blade design, based on the previous research. The outline of wind turbine picked here is an H-sort Darrieus VAWT which deals with the lift drive of the wind. Findings- Active Pitch controlled VAWT with individual pitch control of each blade along with vertical roller bearings in the system is done to obtainmaximum coefficient of power harnessed from the wind turbine setup and increase the efficiency by 12.5%. Applications: The proposed design system is suitable for low wind speed areas which turbine is installed at lower heights.

On the Mathematical Modelling of Adaptive Darrieus Wind Turbine

Darrieus wind turbines are experiencing a renewed interest for their application in decentralized power generation and urban installation. Much attention and research efforts have been dedicated in the past to develop as an efficient standalone Darrieus turbine. Despite these efforts, these vertical axis turbines are still low in efficiency compared to the horizontal axis counterparts. The current architecture of the turbine and their inherent characteristics limit their application in low wind speed areas as confirmed experimentally and computationally by past research. To enable and extend their operation for weak wind flows, a novel design of Adaptive Darrieus Wind Turbine (ADWT) is proposed. The hybrid Darrieus Savonius rotor with dynamically varying Savonius rotor diameter based on the wind speed enables the turbine to start, efficiently operate and stop the turbine at high winds. As the wake of Savonius rotor has a profound impact on the power performance of the combined rotor, the wake of two buckets Savonius rotor in open and closed configuration is reviewed. The current study aims to develop an analytical model to predict the power coefficient and the influence of other design parameters on the proposed design. The formulated analytical model is coded in python, and the results are obtained for the 10 kW rotor. Parametric analysis on the chord length and the diameter of the closed Savonius rotor is performed in search of an optimized diameter to maximize the annual energy output. Blade torque and the rotor torque are evaluated with respect to azimuthal angle and compared with conventional Darrieus rotor. The computed results show that peak power coefficient of ADWT is 13% lower than the conventional Darrieus rotor at the rated wind speed of 10 m/s.

Torsional Vibration Reduction with Augmented Inverse Model-based Controller in Wind Turbine Drivetrain

Wind energy has shown promising advantages in reducing the greenhouse effect by minimizing carbon dioxide emissions to improve earth climate. Wind turbine which falls under the umbrella of renewable energy family promises cleaner environment while generating electricity from wind energy with no burnt fossil fuel. However, it portrays challenges in terms of high operating cost due to component failure. Thus this paper discusses on mitigating one of the problems related to wind turbine failure, the torsional vibration reduction in drive train. A generator torque control is investigated together with the particle swarm optimization technique in search for accurate parameters of the controller. This control strategy is a solution to low wind speed areas especially around South East Asian region. An augmented inverse model-based controller and band pass filter is proposed to obtain vibration attenuation at the dominant mode. The modelling endeavor is firstly obtained via particle swarm optimization search capability to obtain an accurate transfer function of the inverse model. A band pass filter (BPF) is then augmented with the inverse model as controller for torsional vibration suppression. Results have shown favorable comparison between the proposed and conventional methods in terms of vibration attenuation level.

DESAIN DAN ANALISIS WIND TURBINE PROTOTYPE TIPE PROPELLER POROS HORIZONTAL MENGGUNAKAN AIRFOIL AH79100 C BERBAHAN DASAR KOMPOSIT

The utilization of renewable energy at a low wind speed area (namely 2 m /s until 8 m / s) like Indonesia is still rarely performed due to it is low efficiency. This research is intended to know the performance of horizontal axis wind turbine propeller type 5-bladed, using airfoil AH79-100C type with 1,1 m it is diameter. It is expected which the parameters and characteristics of the blade can be used as reference to create a small-scale wind turbine. The results showed that the value of the power coefficient (Cp) is best obtained at a speed of 6 m / s with a value of 44,26%, while for the smallest power coefficient values obtained at wind speed of 17 m / s amounted to 16,76%. This wind turbine are most suitable for use at wind speeds ranging from 6 m / s to 12 m / s.

Experimental study of two-stage Savonius rotors with different gap ratios and phase shift angles

The Savonius rotor has been attracting more and more attention in recent years owing to its appealing features, such as simplicity of the fabrication, cost-effectiveness in low wind speed areas and low noise levels. It can be used for lighting, ventilation, hydropower generation and irrigation. As a traditional single-stage two-blade Savonius rotor has two defects, researchers proposed the multi-stage two-blade Savonius rotor to overcome them. However, most of the previous studies on the multi-stage Savonius rotors focused on the comparison between one- and two-stage rotors or the effect of the aspect ratios. This paper is different from previous researches and focuses on the comparison between two-stage rotors through the wind tunnel test. It also studies the effect of the gap ratio (GR) and phase shift angle (PSA) on the performance of the two-stage rotors at different wind speeds. Results showed that the negative azimuth angle range was narrowed and the torque coefficient (CT) values were improved as GR and PSA increased. Hence, the two-stage rotor with larger GR and PSA can overcome the two defects of the single-stage rotor. In terms of the power coefficient (CP), the optimized performance was determined by the GRs, PSAs, and wind speeds. When the wind speed increased, the difference among CP curves of one tested rotor was reduced. Generally speaking, the rotors with GR = 1/6 exhibited the optimized performance compared with those with other GRs when the PSA = 0° and PSA = 45°. While keeping the PSA = 90°, the rotor with GR = 0 had a superior performance to the others when PSA = 90° at wind speed of 4 m/s. The rotor with GR = 1/3 gave the highest CP value of 0.303 in the vicinity of the tip speed ratio 0.9 at wind speed of 6 m/s. And the rotor with GR = 1/6 attained the best CP when the wind speeds were 8 m/s and 10 m/s.

Optimizing the wind power generation in low wind speed areas using an advanced hybrid RBF neural network coupled with the HGA-GSA optimization method

Enhancing the energy production from wind power in low-wind areas has always been a fundamental subject of research in the field of wind energy industry. In the first phase of this research, an initial investigation was performed to evaluate the potential of wind in south west of Iran. The initial results indicate that the wind potential in the studied location is not sufficient enough and therefore the investigated region is identified as a low wind speed area. In the second part of this study, an advanced optimization model was presented to regulate the torque in the wind generators. For this primary purpose, the torque of wind turbine is adjusted using a Proportional and integral (PI) control system so that at lower speeds of the wind, the power generated by generator is enhanced significantly. The proposed model uses the RBF neural network to adjust the net obtained gains of the PI controller for the purpose of acquiring the utmost electricity which is produced through the generator. Furthermore, in order to edify and instruct the neural network, the optimal data set is obtained by a Hybrid genetic algorithm along with a gravitational search algorithm (HGA-GSA). The proposed method is evaluated by using a 5MW wind turbine manufactured by National Renewable Energy Laboratory (NREL). Final results of this study are indicative of the satisfactory and successful performance of the proposed investigated model.

Micro-Turbine Design, Production and Testing

Large scale utilization of electricity started at the end of 19th century with the construction first power plant and there phase current was introduced. Power plant technology evolved rapidly and electricity use has increased rapidly since then. Outbreak of energy crisis in 1970s and threat of the global warming has forced the people to search clean energy resources. Among the renewable energy sources, wind energy has become the most popular case. Development of the necessary technology for wind turbines reached a commercial competence In the 1990s. Turning to wind energy in Turkey began after 2006 and has shown a rapid increase until 2015. When considering the country's wind potential it tends to stay in rapid growth. In this study, 2 kW micro-turbines is designed, manufactured and tested by using local facility. The aim of this study is to design a micro-turbine for use in low wind speed area, create industrial infrastructure related to the production of micro-turbine, and develop different production technologies for local industry.

A preliminary energy and environmental assessment of a micro wind turbine prototype in natural protected areas

This paper presents a preliminary energy and environmental analysis of a vertical-axis micro wind turbine with a nominal electric power of 3.7kW. This prototype is called AM300.The main aim of the paper is to assess the amount of electric energy production of the AM300 and its feasible use in low wind speed areas. Furthermore, analyzing its low environmental impact, a potential installation in a natural protected area was considered.The turbine power curve was estimated by anemometric measurements. Furthermore, foreseeable prototype hybridization with PV array was analyzed.The environmental performance was assessed evaluating the soil, hydro geological, biodiversity and noise impacts. Finally, an analysis of the CO2 emissions avoided is reported. The obtained results show good sustainability perspectives.

Overview and Design of self-acting pitch control mechanism for vertical axis wind turbine using multi body simulation approach

Awareness about wind energy is constantly growing in the world. Especially a demand for small scale wind turbine is increasing and various products are available in market. There are mainly two types of wind turbines, horizontal axis wind turbine and vertical axis wind turbines. Horizontal axis wind turbines are suitable for high wind speed whereas vertical axis wind turbines operate relatively low wind speed area. Vertical axis wind turbines are cost effective and simple in construction as compared to the horizontal axis wind turbine. However, vertical axis wind turbines have inherent problem of self-start inability and has low power coefficient as compare to the horizontal axis wind turbine. These two problems can be eliminated by incorporating the blade pitching mechanism. So, in this paper overview of various pitch control systems is discussed and design of self-acting pitch mechanism is given. A pitch control linkage mechanism for vertical axis wind turbine is modeled by multi-body approach using MSC Software. Aerodynamic loads are predicted from a mathematical model based on double multiple stream tube method. An appropriate airfoil which works at low Reynolds number is selected for blade design. It is also focused on commercialization of the vertical axis wind turbine which incorporates the self-acting pitch control system. These aerodynamic load model will be coupled with the multi-body model in future work for optimization of the pitch control linkage mechanism. A 500 Watt vertical axis wind turbine is designed and it is planned to implement the self-acting pitch control mechanism in real model.

Power Curve of a Wind Generator Suitable for a Low Wind Speed Site to Achieve a High Capacity Factor

It is well known that energy generated by a wind generator (WG) depends on the wind resources at the installation site. In other words, a WG installed in a high wind speed area can produce more energy than that in a low wind speed area. However, a WG installed at a low wind site can produce a similar amount of energy to that produced by a WG installed at a high wind site if the WG is designed with a rated wind speed corresponding to the mean wind speed of the site. In this paper, we investigated the power curve of a WG suitable for Korea's southwestern coast with a low mean wind speed to achieve a high capacity factor (CF). We collected the power curves of the 11 WGs of the 6 WG manufacturers. The probability density function of the wind speed on Korea's southwestern coast was modeled using the Weibull distribution. The annual energy production by the WG was calculated and then the CFs of all of the WGs were estimated and compared. The results indicated that the WG installed on the Korea's southwestern coast could obtain a CF higher than 40 % if it was designed with the lower rated speed corresponding to the mean wind speed at the installation site.

Performance Testing and Dimensional Analysis of Multi-Blade Wind Turbine for Low Wind Speed Applications

This article is to present the study results of small multi blade wind turbine for use in low wind speed area. In this experiment, the wind turbine has a diameter is 1 m, 30 blades. Each blade has the chord length of 6.5 cm, the length of 0.25 m, which has a curvature plate ratio of 0.15, and blade setting angle of 30 degree. Wind turbine was tested by wind tunnel at wind velocity of 3, 4 and 5 m/s. The results from the test run of, this the wind turbine give maximum mechanical power in each wind velocity of 3.66, 9.91 and 21.76 watts, respectively. From the dimensional analysis of wind rotor turbine by using Buckingham Pi theorem, the wind turbine is up to two times as large that is 2 m diameter; give maximum mechanical power increased to 14.64, 39.24 and 87.04 watts, this power can be generate electric power or use for water pumping for a household.

Comparison of Energy Yield of Small Wind Turbines in Low Wind Speed Areas

The objective of this paper is to compare the energy yield and generated electricity cost of several commercially available small wind turbines under low wind speed condition. Many small wind turbines were not able to generate the amount of electricity promised by the manufacturers. The predicted annual energy yield simulated using manufacturers' power curve were sometimes higher than actual measured values by up to a factor of two. Furthermore, above a rotor size of 3 m, large diameter turbines performed better, having both low generated electricity cost ( € /kWh) and high annual energy yield per swept area (kWh/m 2).

Wind tunnel study of pedestrian level wind environment around tall buildings: Effects of building dimensions, separation and podium

It is well known that high-rise buildings affect the surrounding pedestrian level wind environment. In recent years, awareness and concern has increased about the creation of low wind speed areas around tall buildings which may lead to poor out-door air ventilation. In addition, new building developments are often not restricted to a single building, but comprise a row of buildings, which may have complex plan-forms, and some integrating an extensive podium. This paper aims at providing a fundamental understanding of wind–structure interactions that govern the effects of building dimensions and separations, a row of buildings and podium on the pedestrian level wind environment, for both weak and strong wind conditions, by a series of parametric wind tunnel studies. The study area covered an extensive area which covered up to 400 m downstream of the test buildings. The results show that a single wider building created adverse effects on the natural air ventilation at pedestrian level around the building while a taller building improved the near-field air ventilation conditions. In the studies of building separation effects, the results show an adverse effect on natural air ventilation at pedestrian level when the building separations are less than half the building width. Inclusion of a podium was also found to adversely affect the air movement around buildings.

Air concentrating nozzles: a promising option for wind turbines

Although the use of wind turbines has become necessary in many parts of the world, the actual developments in wind turbines do not concern countries where the average wind speeds are low. The paper introduces a new vertical axis wind rotor using a convergent nozzle for low wind speed areas. This paper brings a detailed theoretical and practical study of air concentrating nozzle and the optimum nozzle dimensions have been analysed in detail. A research programme involving wind tunnel tests of five different nozzle models has also been conducted. The length and the outlet area of the nozzle were changed periodically to see their effect on the increase of wind speed. The variation of the output speed with different values of input wind speed, different input areas of nozzle and different lengths of nozzle placed at different distances from the wind tunnel have been outlined in the paper. Results of additional study of the new rotor's performance characteristics using concentrating nozzles have also been outlined.