Linear wind generator (LWG) is a sufficient way of wind energy harnessing process. However, complicated
LWG energy extraction mechanism such as complex system for transferring linear motion to rotational
motion and problems related to changing the angle of attack is resulted to energy dissipation. In the other
hand the linear generator that delivers ocean wave energy to electricity has been developed as a new renewable energy extraction method. Some of the problems associated with this technology are corrosion,
high cost of manufacturing, high requirement for installation and construction, economical consideration,etc. In the most recent works, low dissipation energy in mechanism, low cost, simplicity and high performance are highly regarded as environmentally friendly methods for wind energy extraction mechanisms. In the current study, we would like to introduce a new and efficient method to extract wind energy using airfoil linear wind generator(ALWG). ALWG is a new method that produces liner reciprocating motion via attached airfoils to a mover in a magnetic field in order to generate electricity.The most important advantage of ALWG is its simplicity and its compatibility to all wind situations that can be more controllable relative to ocean-based and also relative to LWG that become challengeable problem.
This paper presents a study analysis of a complete wind energy conversion system, the system based on a doubly fed induction generator (DFIG); a vector control with stator flux orientation of the DFIG is also used to control independently the active and reactive powers. A comparative study have been performed between the conventional PI controller and fuzzy logic control to investigate its dynamic and static performances. This research work involves the study of a phase in advance, to provide effective assistance, to all those who have to make decisions regarding the planning and implementation of wind energy projects. The main objective is to model the wind chain and the use of two types of strategies for the control of this generator to ensure a good regulation we started with the modeling of the wind chain then the modeling of the DFIG and then the use of the two strategies for the regulation of the latter .The complete system is modeled and simulated in the MATLAB/ Simulink. The performance and robustness are analyzed and compared by Matlab / Simulink .Simulation results prove the excellent performance of fuzzy control unit as improving power quality and stability of wind turbine.
Design & Analysis of a Helical Cross Flow TurbineAnish Anand
We investigate the flow past a cross flow hydrokinetic turbine (CFHT)in which a helical blade turns around a shaft perpendicular to the free stream under the hydrodynamic forces exerted by the flow. The ability of a cross flow turbine to rotate in the same direction independent of the water flow direction gives an advantage for hydrokinetic applications.
This type of turbine, while very different from the classical horizontal axis turbine commonly used in the wind energy field, presents advantages in the context of hydro kinetic energy harvesting, such as independence from current direction, including reversibility, stacking, and self-starting without complex pitch mechanisms.
A PROPOSAL FOR WIND-ENERGY CONVERSION FOR LOW WIND–SPEED AREAS OF INDIAIAEME Publication
This is the methodology to conversion of electricity through wind energy using convergent nozzle in low wind speed area. By the help of this process of conversion we convert low wind speed in sufficient power conversion with the use of nozzle. Then this maximizes the wind speed, that maximum wind speed rotate fan blade at useful speed level. And then sufficient amount of energy are produced
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
Wind Turbines: Will they ever become economically feasible? Jeffrey Funk
The cost electricity from wind turbines is still too for most situations and the cost of electricity has fallen very slowly over the last 30 years (about 2% a year). Even worse, the costs have risen over the last two years. These slides show that the falling costs of electricity from wind turbines are primarily from increases in the scale of wind turbines and that the recent increases are probably from increasing the scale of the rotor diameter too much. Increases in the rotor diameter and the height of towers have directly and indirectly led to reductions in the cost of electricity from wind turbines. They have directly led to reductions in cost because the output of a wind turbine is a function of diameter squared and they indirectly led to reductions in cost because output is a function of wind speed cubed and larger wind turbines can handle higher wind speeds. The major challenge for further increasing the scale of wind turbines is finding materials for the turbine blades that have higher strength to weight ratios. Finally, several new wind turbine designs may also lead to lower costs of electricity from wind turbines.
A Novel Approach Concerning Wind Power EnhancementWaqas Tariq
Being a tropical country, Bangladesh does have wind flow throughout the year. However, the prospect for wind energy in Bangladesh is not at satisfactory level due to low average wind velocities at different regions of the country. The field survey data indicated that the wind velocities are relatively higher from the month of May to August, whereas, it is not so for the rest of the year. Therefore, exploiting the wind energy at low wind velocities is a major predicament in creating a sustainable energy resource for a country with inauspicious forthcoming energy crisis. The scope of this paper concentrates on an innovative approach to harness wind power by installing an auxiliary unit which would only assist the primary turbine unit in case the wind velocity falls under the required value. The auxiliary unit would comprise a secondary turbine, which would be operated by a DC motor connected to a battery system that is charged by a solar panel. A specially designed conduit would encompass both the primary and auxiliary turbine units. A CFD simulation utilizing ANSYS FLOTRAN was carried out to investigate the velocity profiles for different pressure differences at different regions of the prototype conduit. A feasibility analysis of the modified system was eventually carried out for the preferred conduit design.
This paper presents a study analysis of a complete wind energy conversion system, the system based on a doubly fed induction generator (DFIG); a vector control with stator flux orientation of the DFIG is also used to control independently the active and reactive powers. A comparative study have been performed between the conventional PI controller and fuzzy logic control to investigate its dynamic and static performances. This research work involves the study of a phase in advance, to provide effective assistance, to all those who have to make decisions regarding the planning and implementation of wind energy projects. The main objective is to model the wind chain and the use of two types of strategies for the control of this generator to ensure a good regulation we started with the modeling of the wind chain then the modeling of the DFIG and then the use of the two strategies for the regulation of the latter .The complete system is modeled and simulated in the MATLAB/ Simulink. The performance and robustness are analyzed and compared by Matlab / Simulink .Simulation results prove the excellent performance of fuzzy control unit as improving power quality and stability of wind turbine.
Design & Analysis of a Helical Cross Flow TurbineAnish Anand
We investigate the flow past a cross flow hydrokinetic turbine (CFHT)in which a helical blade turns around a shaft perpendicular to the free stream under the hydrodynamic forces exerted by the flow. The ability of a cross flow turbine to rotate in the same direction independent of the water flow direction gives an advantage for hydrokinetic applications.
This type of turbine, while very different from the classical horizontal axis turbine commonly used in the wind energy field, presents advantages in the context of hydro kinetic energy harvesting, such as independence from current direction, including reversibility, stacking, and self-starting without complex pitch mechanisms.
A PROPOSAL FOR WIND-ENERGY CONVERSION FOR LOW WIND–SPEED AREAS OF INDIAIAEME Publication
This is the methodology to conversion of electricity through wind energy using convergent nozzle in low wind speed area. By the help of this process of conversion we convert low wind speed in sufficient power conversion with the use of nozzle. Then this maximizes the wind speed, that maximum wind speed rotate fan blade at useful speed level. And then sufficient amount of energy are produced
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
Wind Turbines: Will they ever become economically feasible? Jeffrey Funk
The cost electricity from wind turbines is still too for most situations and the cost of electricity has fallen very slowly over the last 30 years (about 2% a year). Even worse, the costs have risen over the last two years. These slides show that the falling costs of electricity from wind turbines are primarily from increases in the scale of wind turbines and that the recent increases are probably from increasing the scale of the rotor diameter too much. Increases in the rotor diameter and the height of towers have directly and indirectly led to reductions in the cost of electricity from wind turbines. They have directly led to reductions in cost because the output of a wind turbine is a function of diameter squared and they indirectly led to reductions in cost because output is a function of wind speed cubed and larger wind turbines can handle higher wind speeds. The major challenge for further increasing the scale of wind turbines is finding materials for the turbine blades that have higher strength to weight ratios. Finally, several new wind turbine designs may also lead to lower costs of electricity from wind turbines.
A Novel Approach Concerning Wind Power EnhancementWaqas Tariq
Being a tropical country, Bangladesh does have wind flow throughout the year. However, the prospect for wind energy in Bangladesh is not at satisfactory level due to low average wind velocities at different regions of the country. The field survey data indicated that the wind velocities are relatively higher from the month of May to August, whereas, it is not so for the rest of the year. Therefore, exploiting the wind energy at low wind velocities is a major predicament in creating a sustainable energy resource for a country with inauspicious forthcoming energy crisis. The scope of this paper concentrates on an innovative approach to harness wind power by installing an auxiliary unit which would only assist the primary turbine unit in case the wind velocity falls under the required value. The auxiliary unit would comprise a secondary turbine, which would be operated by a DC motor connected to a battery system that is charged by a solar panel. A specially designed conduit would encompass both the primary and auxiliary turbine units. A CFD simulation utilizing ANSYS FLOTRAN was carried out to investigate the velocity profiles for different pressure differences at different regions of the prototype conduit. A feasibility analysis of the modified system was eventually carried out for the preferred conduit design.
Modeling and Control of a Doubly-Fed Induction Generator for Wind Turbine-Gen...IJPEDS-IAES
This paper presents a vector control direct (FOC) of double fed induction generator intended to control the generated stator powers. This device is intended to be implemented in a variable-speed wind-energy conversion system connected to the grid. In order to control the active and reactive power exchanged between the machine stator and the grid, the rotor is fed by a bi-directional converter. The DFIG is controlled by standard relay controllers. Details of the control strategy and system simulation were performed using Simulink and the results are presented in this here to show the effectiveness of the proposed control strategy.
Using position control to improve the efficiency of wind turbineTELKOMNIKA JOURNAL
Wind energy is one of the renewable energies that can be using to generate electricity. Increasing demand for this type of renewable energy for sustainability and accessibility. Environmentally as it does not cause any pollution in addition to the abundance of required equipment and lessmaintenance and long operation life of its parts despite the high cost of the system at its installation but at long term, become cheaper. Wind power generators depend on their operation on wind speed and direction. Therefore,it should be installing in places where the wind speed is adequate and sufficient to rotate its rotor, it knows that wind speed is variable in its speed and direction they change every hour and every season. In this design, many practical and theoretical (simulation) experiments have been done which will be mentioned and explained in details in this research shows that this mechanism raises the efficiency of wind power generators by 80% when the rotor of the wind turbine directed towards the wind than if they were fixed direction.
Modeling of Wind Energy on Isolated AreaIJPEDS-IAES
In this paper, a model of the wind turbine (WT) with permanent magnet generator (PMSG) and its associated controllers is presented. The increase of wind power penetration in power systems has meant that conventional power plants are gradually being replaced by wind farms. In fact, today wind farms are required to actively participate in power system operation in the same way as conventional power plants. In fact, power system operators have revised the grid connection requirements for wind turbines and wind farms and now demand that these installations be able to carry out more or less the same control tasks as conventional power plants. For dynamic power system simulations, the PMSG wind turbine model includes an aerodynamic rotor model, a lumped mass representation of the drive train system and generator model. In this paper we propose a model with an implementation in MATLAB / Simulink, each of the system components off-grid small wind turbines.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
The purpose of this work is to present the advantages of the power control (active and reactive) of a wind energy system in order to improve the quality of the energy produced to the grid by presenting two control strategies applied to the conversion system of wind energy equipped with an asynchronous generator with dual power supply. Both techniques are studied and developed and consist of a field control (FOC) and a sliding mode control. They find their strongest justifications for the problem of using a nonlinear control law that is robust to the uncertainties of the model. The goal is to apply these two commands to independently control the active and reactive powers generated by the decoupled asynchronous machine by flow orientation. Thus, a study of these commands will be detailed and validated in the Matlab / Simulink environment with the simultaneous use of the "Pitch Control" and "Maximum Power Point Tracking (MPPT)" techniques. The results of numerical simulations obtained show the increasing interest of the two controls in the electrical systems. They also attest that the quality of the active and reactive powers and voltages of the wind system is considerably improved.
A Review and Aspects of High Altitude Wind Power GenerationAyyarao T S L V
With the consciousness on green energy as well as the positive industrial growth outlook, the energy gap between the demand and supply has to be filled by renewable energy sources alone. This paved for a renewed interest in wind energy systems. Though there is a good research already been done in low altitude wind power extraction, the focus on high altitude wind energy systems is undermined. There is a tremendous scope as well as challenges associated with these systems. This paper investigates the paradigms, generator selection, generation control and transmission modes of high altitude wind energy systems. Also various aspects of feasibility, installation and control methods are critically reviewed.
An Overview of Wind Power Generation and Design Aspects in Indiaijiert bestjournal
There is huge activity in wind power,pan-India with the instal led capacity increasing to 10,000MW. India today has the fifth largest installed capacity of wind power in the world w ith 11087MW installed capacity and potential for on-shore capabilities of 65000MW. However the plant load factor (PLF) in wi nd power generation is very low,often in the single digits. The increase in interest in wind energy is due to inves tment subsidies,tax holidays,and government action towards renewable energy playing a big part in nation�s energy system. T here is a need to generate environment friendly power that not only raises energy efficiency and is sustainable too. The time has come for moving to generation based subsidies and understanding the drawbacks associated with wind power in India. The capital cost of wind power is third higher than Conventional thermal power;further electrical problems like v oltage flicker and variable frequency affect the implementation of wind farm. However advances in technologies such as offshore construction of wind turbines,advanced control methodologies,and simulation of wind energy affecting over all grid performance are making a case for wind energy.
Analysis and Comparisons of Different Type of WCES- A Literature Reviewpaperpublications3
Abstract: With very rapid development of wind power technologies and significant growth of wind power capacity installed worldwide, various wind turbine concepts have been developed. The wind energy conversion system is required to be more cost-competitive, so that comparisons of different wind generator systems are necessary. A literature review of different types wind energy conversion systems is presented. First, the modern wind turbines are described with respect to both their control features and drive train types, and their advantages and disadvantages are described. Then, the quantitative comparison and market penetration of different wind generator systems are presented. The promising permanent magnet generator types are also investigated. After that the ongoing trends of wind generator systems and related comparison criteria are discussed.
The objective of this paper is to provide an overview of the current state of renewable energy resources in Bangladesh, as well as to examine various forms of renewable energies in order to gain a comprehensive understanding of how to address Bangladesh's power crisis issues in a sustainable manner. Electricity is currently the most useful kind of energy in Bangladesh. It has a substantial influence on a country's socioeconomic standing and living standards. Maintaining a stable source of energy at a cost that is affordable to everyone has been a constant battle for decades. Bangladesh is blessed with a wealth of natural resources. Bangladesh has a huge opportunity to accelerate its economic development while increasing energy access, livelihoods, and health for millions of people in a sustainable way due to the renewable energy system.
Design of Lattice Wind Turbine Towers With Structural OptimizationIJERA Editor
This article aims to study the self-supporting truss towers used to support large wind turbines in areas with high altitude. The goal is to evaluate and validate numerically by finite element method the structural analysis when the lattice structures of the towers of wind turbines are subjected to static loads and these from common usage. With this, it is expected minimize the cost of transportation and installation of the tower and maximize the generation of electricity, respecting technical standards and restrictions of structural integrity and safety, making vibration analysis and the required static and dynamic loads, thereby preventing failures by fractures or mechanical fatigue. Practical examples of towers will be designed by the system and will be tested in structural simulation programs using the Finite Element Method. This analysis is done on the entire region coupling action of the turbine, with variable sensitivity to vibration levels. The results obtained for freestanding lattice tower are compared with the information of a tubular one designed to support the generator with the same characteristics. At the end of this work itwas possible to observe the feasibility of using lattice towers that proved better as its structural performance but with caveats about its dynamic performance since the appearance of several other modes natural frequency thus reducing the intervals between them in low frequency and theoretically increase the risk of resonance.
This paper proposes a feedback linearization control of doubly fed induction generator based wind energy systems for improving decoupled control of the active and reactive powers stator. In order to enhance dynamic performance of the controller studied, the adopted control is reinforced by a fuzzy logic controller. This approach is designed without any model of rotor flux estimation. The difficulty of measuring of rotor flux is overcome by using high gain observer. The stability of the nonlinear observer is proved by the Lyapunov theory. Numerical simulations using MATLAB-SIMULINK shown clearly the robustness of the proposed control, particularly to the disturbance rejection and parametric variations compared with the conventional method.
Study of Wind Turbine based Variable Reluctance Generator using Hybrid FEMM-M...Yayah Zakaria
Based on exhaustive review of the state of the art of the electric generators fitted to Wind Energy Conversion System (WECS), this study is focused on an innovative machine that is a Variable Reluctance Generator (VRG). Indeed, its simple and rugged structure (low cost), its high torque at low speed (gearless), its fault-tolerance (lowest maintenance), allow it to be a potential candidate for a small wind power application at variable wind
speed. For better accuracy, a finite element model of a studied doubly salient VRG is developed using open source software FEMM to identify the electromagnetic characteristics such as linkage flux, torque or inductance versus rotor position and stator excitation. The obtained data are then transferred into look-up tables of MATLAB/Simulink to perform various simulations. Performance of the proposed wind power system is analyzed for several parameters and results are discussed.
Experimental validation of effect of equivalence ratio on detonation characte...ijmech
Experimental studies were carried out for using Propane as fuel for Pulse Detonation Engine application. In the present study Detonation Characteristics of Propane & Oxygen mixture at various equivalence ratios were presented. In these experiments Propane and Oxygen under regulated pressures were injected into a Detonation Tube from the head end using unlike impinging doublet injector. The fuel and oxidizer were allowed to mix and fill the tube. Subsequently, the mixture was ignited using a spark plug positioned close to the head end of the tube. The pressures generated due to the combustion of the mixtures were captured using five high frequency pressure transducers which were spaced 100mm apart on the detonation tube. Apart from these pressures, velocities of the combustion wave were computed using ‘time of flight’ method. These
tests were done for different equivalence ratios varying from 0.8 to 1.6 by varying the feeding pressure of
Propane. In the present study the performance of the combustion wave at different locations and effect of
equivalence ratios on detonation characteristics were presented. In addition effect of presence of obstacles in
the flow path i.e., Shchelkin spirals were also studied in reducing the Deflagration to Detonation Transition
(DDT) distance.
EXPERIMENTAL AND PERFORMANCE ANALYSIS OF SINGLE NOZZLE JET PUMP WITH VARIOUS ...ijmech
Water is central to survival, without water human, plant and animal life would be impossible. Therefore supply of water has become one of the fundamental requirements of any society and the need to transfer water has generated the design of various forms of mechanical devices, which can be categorized as pumps. Jet pump is a device that performs its pumping action by the transfer of energy from a high velocity supply jet to one of low velocity suction flow. These two flows mix in the mixing tube and the kinetic energy of the combined flow is converted partially into the pressure energy in the diffuser. The optimization of the design of single hole nozzle jet pump with various area ratios and five different diameter mixing tubes. For
each of the mixing tube, experiments were conducted for two more distances above and the one used for the
first set of experiments. The spacing was increased using 2 (6 mm) gaskets for one distance and 3 (9 mm)
gaskets for another distance. The area ratios chosen have been modified and the final area ratios used were R = 0.20, 0.28, 0.36, 0.43 & 0.50. Discharge ratios (M), Head ratio (N), Efficiency () were used to draw performance curves. Experiments were done for all other area ratios as spacing is increasing there is an increase in efficiency.
technoloTwo dimensional numerical simulation of the combined heat transfer in...ijmech
A numerical investigation was conducted to analyze the flow field and heat transfer characteristics in a vertical channel withradiation and blowing from the wall. Hydrodynamic behaviour and heat transfer results are obtained by the solution of the complete Navier–Stokesand energy equations using a control volume finite element method. Turbulent flow with "Low Reynolds Spalart-Allmaras Turbulence Model" and radiation with "Discrete Transfer Radiation Method" had been modeled. In order to have a complete survey, this article has a wide range of study in different domains including velocity profiles at different locations, turbulent viscosity, shear stress, suctioned mass flow rate in different magnitude of the input
Rayleigh number, blowing Reynoldsnumber, radiation parameter, Prandtl number, the ratio of length to width and also ratio of opening thickness to width of the channel. In addition, effects of variation in any of the above non-dimensional numbers on parameters of the flow are clearly illustrated. At the end resultants had been compared with experimental data which demonstrated that in the present study, results have a great accuracy, relative errors are very small and the curve portraits are in a great
agreement with real experiments.
Modeling and Control of a Doubly-Fed Induction Generator for Wind Turbine-Gen...IJPEDS-IAES
This paper presents a vector control direct (FOC) of double fed induction generator intended to control the generated stator powers. This device is intended to be implemented in a variable-speed wind-energy conversion system connected to the grid. In order to control the active and reactive power exchanged between the machine stator and the grid, the rotor is fed by a bi-directional converter. The DFIG is controlled by standard relay controllers. Details of the control strategy and system simulation were performed using Simulink and the results are presented in this here to show the effectiveness of the proposed control strategy.
Using position control to improve the efficiency of wind turbineTELKOMNIKA JOURNAL
Wind energy is one of the renewable energies that can be using to generate electricity. Increasing demand for this type of renewable energy for sustainability and accessibility. Environmentally as it does not cause any pollution in addition to the abundance of required equipment and lessmaintenance and long operation life of its parts despite the high cost of the system at its installation but at long term, become cheaper. Wind power generators depend on their operation on wind speed and direction. Therefore,it should be installing in places where the wind speed is adequate and sufficient to rotate its rotor, it knows that wind speed is variable in its speed and direction they change every hour and every season. In this design, many practical and theoretical (simulation) experiments have been done which will be mentioned and explained in details in this research shows that this mechanism raises the efficiency of wind power generators by 80% when the rotor of the wind turbine directed towards the wind than if they were fixed direction.
Modeling of Wind Energy on Isolated AreaIJPEDS-IAES
In this paper, a model of the wind turbine (WT) with permanent magnet generator (PMSG) and its associated controllers is presented. The increase of wind power penetration in power systems has meant that conventional power plants are gradually being replaced by wind farms. In fact, today wind farms are required to actively participate in power system operation in the same way as conventional power plants. In fact, power system operators have revised the grid connection requirements for wind turbines and wind farms and now demand that these installations be able to carry out more or less the same control tasks as conventional power plants. For dynamic power system simulations, the PMSG wind turbine model includes an aerodynamic rotor model, a lumped mass representation of the drive train system and generator model. In this paper we propose a model with an implementation in MATLAB / Simulink, each of the system components off-grid small wind turbines.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
The purpose of this work is to present the advantages of the power control (active and reactive) of a wind energy system in order to improve the quality of the energy produced to the grid by presenting two control strategies applied to the conversion system of wind energy equipped with an asynchronous generator with dual power supply. Both techniques are studied and developed and consist of a field control (FOC) and a sliding mode control. They find their strongest justifications for the problem of using a nonlinear control law that is robust to the uncertainties of the model. The goal is to apply these two commands to independently control the active and reactive powers generated by the decoupled asynchronous machine by flow orientation. Thus, a study of these commands will be detailed and validated in the Matlab / Simulink environment with the simultaneous use of the "Pitch Control" and "Maximum Power Point Tracking (MPPT)" techniques. The results of numerical simulations obtained show the increasing interest of the two controls in the electrical systems. They also attest that the quality of the active and reactive powers and voltages of the wind system is considerably improved.
A Review and Aspects of High Altitude Wind Power GenerationAyyarao T S L V
With the consciousness on green energy as well as the positive industrial growth outlook, the energy gap between the demand and supply has to be filled by renewable energy sources alone. This paved for a renewed interest in wind energy systems. Though there is a good research already been done in low altitude wind power extraction, the focus on high altitude wind energy systems is undermined. There is a tremendous scope as well as challenges associated with these systems. This paper investigates the paradigms, generator selection, generation control and transmission modes of high altitude wind energy systems. Also various aspects of feasibility, installation and control methods are critically reviewed.
An Overview of Wind Power Generation and Design Aspects in Indiaijiert bestjournal
There is huge activity in wind power,pan-India with the instal led capacity increasing to 10,000MW. India today has the fifth largest installed capacity of wind power in the world w ith 11087MW installed capacity and potential for on-shore capabilities of 65000MW. However the plant load factor (PLF) in wi nd power generation is very low,often in the single digits. The increase in interest in wind energy is due to inves tment subsidies,tax holidays,and government action towards renewable energy playing a big part in nation�s energy system. T here is a need to generate environment friendly power that not only raises energy efficiency and is sustainable too. The time has come for moving to generation based subsidies and understanding the drawbacks associated with wind power in India. The capital cost of wind power is third higher than Conventional thermal power;further electrical problems like v oltage flicker and variable frequency affect the implementation of wind farm. However advances in technologies such as offshore construction of wind turbines,advanced control methodologies,and simulation of wind energy affecting over all grid performance are making a case for wind energy.
Analysis and Comparisons of Different Type of WCES- A Literature Reviewpaperpublications3
Abstract: With very rapid development of wind power technologies and significant growth of wind power capacity installed worldwide, various wind turbine concepts have been developed. The wind energy conversion system is required to be more cost-competitive, so that comparisons of different wind generator systems are necessary. A literature review of different types wind energy conversion systems is presented. First, the modern wind turbines are described with respect to both their control features and drive train types, and their advantages and disadvantages are described. Then, the quantitative comparison and market penetration of different wind generator systems are presented. The promising permanent magnet generator types are also investigated. After that the ongoing trends of wind generator systems and related comparison criteria are discussed.
The objective of this paper is to provide an overview of the current state of renewable energy resources in Bangladesh, as well as to examine various forms of renewable energies in order to gain a comprehensive understanding of how to address Bangladesh's power crisis issues in a sustainable manner. Electricity is currently the most useful kind of energy in Bangladesh. It has a substantial influence on a country's socioeconomic standing and living standards. Maintaining a stable source of energy at a cost that is affordable to everyone has been a constant battle for decades. Bangladesh is blessed with a wealth of natural resources. Bangladesh has a huge opportunity to accelerate its economic development while increasing energy access, livelihoods, and health for millions of people in a sustainable way due to the renewable energy system.
Design of Lattice Wind Turbine Towers With Structural OptimizationIJERA Editor
This article aims to study the self-supporting truss towers used to support large wind turbines in areas with high altitude. The goal is to evaluate and validate numerically by finite element method the structural analysis when the lattice structures of the towers of wind turbines are subjected to static loads and these from common usage. With this, it is expected minimize the cost of transportation and installation of the tower and maximize the generation of electricity, respecting technical standards and restrictions of structural integrity and safety, making vibration analysis and the required static and dynamic loads, thereby preventing failures by fractures or mechanical fatigue. Practical examples of towers will be designed by the system and will be tested in structural simulation programs using the Finite Element Method. This analysis is done on the entire region coupling action of the turbine, with variable sensitivity to vibration levels. The results obtained for freestanding lattice tower are compared with the information of a tubular one designed to support the generator with the same characteristics. At the end of this work itwas possible to observe the feasibility of using lattice towers that proved better as its structural performance but with caveats about its dynamic performance since the appearance of several other modes natural frequency thus reducing the intervals between them in low frequency and theoretically increase the risk of resonance.
This paper proposes a feedback linearization control of doubly fed induction generator based wind energy systems for improving decoupled control of the active and reactive powers stator. In order to enhance dynamic performance of the controller studied, the adopted control is reinforced by a fuzzy logic controller. This approach is designed without any model of rotor flux estimation. The difficulty of measuring of rotor flux is overcome by using high gain observer. The stability of the nonlinear observer is proved by the Lyapunov theory. Numerical simulations using MATLAB-SIMULINK shown clearly the robustness of the proposed control, particularly to the disturbance rejection and parametric variations compared with the conventional method.
Study of Wind Turbine based Variable Reluctance Generator using Hybrid FEMM-M...Yayah Zakaria
Based on exhaustive review of the state of the art of the electric generators fitted to Wind Energy Conversion System (WECS), this study is focused on an innovative machine that is a Variable Reluctance Generator (VRG). Indeed, its simple and rugged structure (low cost), its high torque at low speed (gearless), its fault-tolerance (lowest maintenance), allow it to be a potential candidate for a small wind power application at variable wind
speed. For better accuracy, a finite element model of a studied doubly salient VRG is developed using open source software FEMM to identify the electromagnetic characteristics such as linkage flux, torque or inductance versus rotor position and stator excitation. The obtained data are then transferred into look-up tables of MATLAB/Simulink to perform various simulations. Performance of the proposed wind power system is analyzed for several parameters and results are discussed.
Experimental validation of effect of equivalence ratio on detonation characte...ijmech
Experimental studies were carried out for using Propane as fuel for Pulse Detonation Engine application. In the present study Detonation Characteristics of Propane & Oxygen mixture at various equivalence ratios were presented. In these experiments Propane and Oxygen under regulated pressures were injected into a Detonation Tube from the head end using unlike impinging doublet injector. The fuel and oxidizer were allowed to mix and fill the tube. Subsequently, the mixture was ignited using a spark plug positioned close to the head end of the tube. The pressures generated due to the combustion of the mixtures were captured using five high frequency pressure transducers which were spaced 100mm apart on the detonation tube. Apart from these pressures, velocities of the combustion wave were computed using ‘time of flight’ method. These
tests were done for different equivalence ratios varying from 0.8 to 1.6 by varying the feeding pressure of
Propane. In the present study the performance of the combustion wave at different locations and effect of
equivalence ratios on detonation characteristics were presented. In addition effect of presence of obstacles in
the flow path i.e., Shchelkin spirals were also studied in reducing the Deflagration to Detonation Transition
(DDT) distance.
EXPERIMENTAL AND PERFORMANCE ANALYSIS OF SINGLE NOZZLE JET PUMP WITH VARIOUS ...ijmech
Water is central to survival, without water human, plant and animal life would be impossible. Therefore supply of water has become one of the fundamental requirements of any society and the need to transfer water has generated the design of various forms of mechanical devices, which can be categorized as pumps. Jet pump is a device that performs its pumping action by the transfer of energy from a high velocity supply jet to one of low velocity suction flow. These two flows mix in the mixing tube and the kinetic energy of the combined flow is converted partially into the pressure energy in the diffuser. The optimization of the design of single hole nozzle jet pump with various area ratios and five different diameter mixing tubes. For
each of the mixing tube, experiments were conducted for two more distances above and the one used for the
first set of experiments. The spacing was increased using 2 (6 mm) gaskets for one distance and 3 (9 mm)
gaskets for another distance. The area ratios chosen have been modified and the final area ratios used were R = 0.20, 0.28, 0.36, 0.43 & 0.50. Discharge ratios (M), Head ratio (N), Efficiency () were used to draw performance curves. Experiments were done for all other area ratios as spacing is increasing there is an increase in efficiency.
technoloTwo dimensional numerical simulation of the combined heat transfer in...ijmech
A numerical investigation was conducted to analyze the flow field and heat transfer characteristics in a vertical channel withradiation and blowing from the wall. Hydrodynamic behaviour and heat transfer results are obtained by the solution of the complete Navier–Stokesand energy equations using a control volume finite element method. Turbulent flow with "Low Reynolds Spalart-Allmaras Turbulence Model" and radiation with "Discrete Transfer Radiation Method" had been modeled. In order to have a complete survey, this article has a wide range of study in different domains including velocity profiles at different locations, turbulent viscosity, shear stress, suctioned mass flow rate in different magnitude of the input
Rayleigh number, blowing Reynoldsnumber, radiation parameter, Prandtl number, the ratio of length to width and also ratio of opening thickness to width of the channel. In addition, effects of variation in any of the above non-dimensional numbers on parameters of the flow are clearly illustrated. At the end resultants had been compared with experimental data which demonstrated that in the present study, results have a great accuracy, relative errors are very small and the curve portraits are in a great
agreement with real experiments.
Performance prediction of a turboshaft engine by using of one dimensional ana...ijmech
Performance estimation of the axial flow gas turbines under variety of operating conditions like different speeds and pressure ratios has been hampered by lack of reliable experimental data and experiments cost.Simulation of gas turbine is a simple way to reduce testing costs and complexity.One-dimensional (1D).Simulation is a simple, fast and accurate method for performance prediction of turbine with different geometries. In this approach, inlet flow conditions and turbine geometry are known and by considering loss model, the turbine performance characteristics are predicted. In following work, that is based on one dimensional modelling method, after the presentation of solution algorithm by trial and error method and introduction of different loss models for modelling, this method were examined for a turbo shaft engine and
compared with experimental results. Comparison of the results with experimental data shows so good adaptation. Also according to these results, Kacker and Okapuu’s developed model gave the closest results to the reference data.
THERMAL PERFORMANCE TESTING OF A FLAT PLATE SOLAR AIR HEATER USING OPTICAL ME...ijmech
Experimental test set up at laboratory scale has been developed for thermal performance testing of flat
plate solar air heater with simulated solar radiation intensity; 600W/m2. A test cell of size 1m x 0.5m x
0.1m was fabricated. Three designs namely (i) plane absorber (ii) transverse V- porous ribs and (iii)
inclined V-porous ribs of absorber are tested. All the experiments are conducted with artificial solar
radiation and in natural convection. Performances of these three designs have been compared on the basis
of overall thermal efficiency and thermal gradient along normal to the base. Thermal gradient has been
determined by laser beam deviation method. PT-100 temperature sensors have also been used to validate
the optical results of thermal gradient. The overall thermal efficiencies of these designs have been found as
14.91%, 17.24% and 20.04% respectively. It has also been seen that thermal gradient tends to reduce with
increase in efficiency.
ULTIMATE LIMIT STATE ASSESSMENT OF STIFFENED PANEL STRUCTURES FOR VERY LARGE ...ijmech
Reduces weight of hull structures designed for a very large carrier plays an important role as the economic
efficiency is the most significant aspect. It is known that the traditional allowable working stress
approaches with high safety and reliability, it means that the hull structural weight is higher than the
actual requirement in operation. Recently, the limit state approach has been widely applied for analysis
and assessment of marine structures, the limit strength of structures is determined by nonlinear finite
element analysis (FEA) method. A Very Large Ore Carrier (VLOC) is designed by using IACS Common
Structural Rules (CSR) method in this article, and pre-CSR method is adopted to improve cross-sectional of
the bottom and deck structures. Given that the stiffened panel under the combination of axial or biaxial
compression and lateral pressure loads for computation, ultimate strength of the ship structures designed
by using the aforementioned method are analyzed by using the nonlinear finite element method (FEM). The
results show that the difference of ultimate strength of ship structures designed by using pre-CSR method
and CSR method is able to neglect. It can be seen that the weight of hull structure can be reduced by 0.56
percent (640 tons in this case) without reducing ultimate strength when pre-CSR method is applied.
Comparative analysis of passenger ride comfort using various semi active susp...ijmech
In this paper, different semi-active control strategies for non-linear quarter car model equipped with controllable magneto-rheological (MR) shock absorbers and fuzzy logic controller are compared.Polynomial model is selected to characterize the experimental results of MR shock absorber. A combination of Forward Fuzzy Logic Controller (FFLC) and Inverse Fuzzy Logic Controller (IFLC) is
designed for proper working of MR shock absorber i.e. generation and supply of control current to MR shock absorber, which provides damping force to suspension system for vibration control purpose.Simulink responses of four different cases are evaluated for passenger ride comfort analysis taking uncontrolled, primary suspension controlled, secondary suspension controlled and fully controlled quarter car models. The obtained results in graphical and mathematical form demonstrate that the fully controlled quarter car system provides excellentperformance in suppression of passenger seat vibrations compared to other control strategies while the vehicle travels over the sinusoidal type of input road profile
COMPARISON OF SURFACE ROUGHNESS OF COLDWORK AND HOT WORK TOOL STEELS IN HARD ...ijmech
The hard turning process has been attracting interest in different industrial sectors for finishing operations
of hard materials at its hardened state.Surface roughness is investigated in hard turning of AISI D3 and
AISI H13 steels of same hardness 62HRC. In this paper, an attempt has been made to model and predict
the surface roughness in hard turning of AISI D3 and AISI H13 hardened steels using Response Surface
Methodology (RSM). The combined effects of three machining parameters such as cutting speed, feed rate
and depth of cut are investigated for main performance characteristic that is surface roughness. RSM
based Central Composite Design (CCD) is applied as an experimental design. Al2O3/TiC mixed ceramic
tool with corner radius 0.8 mm is employed to accomplish 20 tests with six center points. The acceptability
of the developed models is checked using Analysis of Variance (ANOVA).The combined effects of cutting
speed; feed rate and depth of cut are investigated using surface plots.
PARAMETRIC STUDIES ON THE EFFECT OF FOUR TYPES OF FASTENER MODELING IN CHANNE...ijmech
In this paper, some parametric studies on four types of Channel type tension fitting’s fasteners’ stiffness
modeling is presented. Tension fittings are commonly classified into five types. They are Bathtub fitting,
Channel fitting, Angle fitting, ‘PI’ fitting and Double angle fitting. Tension fittings are conservatively sized
as their weight is usually small relative to their importance. In the previous studies, the channel fitting was
considered to be fixed at all the fastener locations. Thus, the results obtained were conservative because
the load was getting reacted at the first line of fasteners only. In order to study the effect of fastener’s
flexibility and hence the load flow inside the tension fitting two methods (Tate & Swift) of fastener modeling
were employed in the previous study. It observed that, the flexible boundary condition allow for a better
load flow into the channel fitting as compared to the fixed boundary condition. In this study, fastener
flexibility with two more methods (Grumann and Huth) is performed on the distribution of internal stresses
in the channel fitting as compared to the fixed boundary conditions. Also comparison of previous results
(Tate and Swift) is made with Grumann and Huth methods of modeling of fastener. Aluminum alloy 7050-
T7452 is selected for the study.
CFD SIMULATION OF SOLDER PASTE FLOW AND DEFORMATION BEHAVIOURS DURING STENCIL...ijmech
In 20th century, Electronics elements have become most significant part of the regular life. The main heart
of electronic element is PCB which supports and manages mostly machines and equipments these days.
Therefore manufacturing of board and assembly of electronic elements is one of the crucial and significant
objectives for most of the companies. Better life of PCB’s depends on electronic elements and its assembly
with board. Solder paste is used as adhesive material for assembly purpose. It is deposited on board using
stencil and electronic elements are mounted on it and heated for strong bond.
This study investigates on factors affecting stencil printing process due to variation in squeegee speed and
density of solder paste. This study is based on computational fluid dynamics virtual simulation. Prototype is
developed for modelling purpose and simulation software is used to simulate the flow behaviour of solder
paste during stencil printing process.
A fuzzy logic model for evaluation of oil film pressure in hydrodynamic bearingijmech
This study presents a new approach for evaluation of oil-film pressure in hydrodynamic bearing. Oil-filmpressure is one of the critical parameter which determines the performance of hydrodynamic bearing. In this research parameters of rotational speed, bearing load and oil-feed pressure are considered as model independent variables. Modelling and simulations are done in Matlab. The research shows that as compared to other conventional techniques approximate fuzzy reasoning provides a more logical approach.
THE STUDY OF THE EFFECTS OF RADIATION AND BLOWING FROM THE WALL OF A VERTICAL...ijmech
This article investigates the effects of radiation and blowing from a wall on a turbulent heat transfer in vertical channels with asymmetrical heating. The equations involved were numerically solved with three turbulent models including SpalartAllmaras, R-N-G k-
with"Standard Wall Function" wall nearby model, R-N-G k- with "Enhanced Wall Treatment" wall nearby model and "Ray Tracing" radiation techniques. The results were compares with experimental data and appropriate methods were selected for turbulent modeling. The problem
of Rayleigh number, Reynolds, radiation parameters and Prandtl were solved and the effects of these parameters on the flow lines, lines of constant temperature, radiation, convection, heat transfer caused by blowing and the total heat transfer were determined.
SIMULTANEOUS OPTIMIZATION OF SEMIACTIVE QUARTER CAR SUSPENSION PARAMETERS USI...ijmech
In present paper, a methodology is presented related to the optimization of semi-active quarter car model
suspension parameters having three degrees of freedom, subjected to bump type of road excitation.
Influence of primary suspension stiffness, primary suspension damping, secondary suspension stiffness and
secondary suspension damping are studied on the passenger ride comfort, taking root mean square (RMS)
values of passenger seat displacement and settling time into account. Semi-active quarter car model
assembled with magneto-rheological (MR) shock absorber is selected for optimization of suspension
parameters using Taguchi method in combination with Grey relational analysis. Confirmatory results with
simulation run indicates that the optimized results of suspension parameters are helpful in achieving the
best ride comfort to travelling passengers in terms of minimization of passenger seat displacement and
settling time values.
DESIGN IMPROVISATION OF ELECTROMECHANICAL ACTUATORS FOR OPERATION AT SUB ZERO...ijmech
Control surface actuators are the key systems in any flight vehicle for enabling a strict control on the flight
parameters. The electromechanical actuator developed for an Unmanned aerial vehicle (UAV) is subjected
to sub-zero temperatures due to the altitude of operation. This paper discusses on how an actuator
developed is studied experimentally and improvised in design to ensure performance at -40oC. The
experimental observations are reasoned and supported by theoretical studies and remedial measures
incorporated to improve the actuator performance.
AMPPS_CNC IN AN AUTOMATED MODULAR PROCESS PLANNING SYSTEM FOR ROTATIONAL PARTijmech
The decision on sequencing of operations, tool travel and machining time calculations is done in microplanning. After a set of processes has been selected for all the features of part, the sequencing task begins by searching and analysing relationship between features. This is done
by rule to detect geometrical interactions and the appropriate precedence relationship in knowledge base. For deciding sequence of operations precedence relationship among the different operations is developed using decision rules. CNC program is generated based on the process plan of a given component. The generated CNC program is then validated by simulation software before giving it to CNC machine.
Increasing life of spur gears with the help of finite element analysisijmech
The Focus of this research is on mathematical analysis of life of gears and reducing noise frequency of gears due to change of material from C-45 to 19mncr5. Calculations for gears life was done with the help of Lewis equation and Buckingham formula. Basically life of a gear is depending upon the stress, more the stress on gear lesser life of gear will be. In this paper some major condition to perform a gear without failure is achieved i.e. tangential force should be less than tangential load to sustain static load, dynamic
load should be less than endurance load to sustain dynamic load and wear load should be less than static
load to sustain wear load. After calculation of 19mncr5 material we evaluate that endurance load acting on the gear which is greater than the dynamic load so our gear come out be safe. Also this study shows declination of noise level in 19mncr5 material compare to C-45 material.
EFFECT OF NOSE RADIUS ON SURFACE ROUGHNESS DURING CNC TURNING USING RESPONSE ...ijmech
The work and study presented in this paper aims to investigate the effect of nose radius on surface
roughness, in CNC turning of Aluminium (6061) in dry condition. The effect of cutting conditions (speed,
feed and depth of cut) and tool geometry (nose radius) on surface roughness were studied and analysed.
Design of Experiments (DOE) were conducted for the analysis of the influence of the turning parameter on
the surface roughness by using Response Surface Methodology (RSM) and then followed by optimization of
the results using Analysis of Variance (ANOVA) to minimize surface roughness. The nose radius was
identified as the most significant parameter. Surface roughness value decreased with increase in nose
radius.
DESIGN AND DEVELOPMENT OF MACHINE FAULT SIMULATOR (MFS) FOR FAULT DIAGNOSISijmech
Recent years have seen the rise of vibration problems associated with structures, which are more delicate
and intricate, machines that are faster, more complex and production process that are automated and
interlinked. The occurred problems are directly related to demands of lower investment, running and
maintenance cost in incidence with the requirement of increase productivity and efficiency. This work
developed aMachine Fault Simulator (MFS),whichis the most comprehensive laboratory scale machine on
the market for performing rotor dynamics experiments.Also, it helps in learning vibration signature of the
most common machinery faults in a controlled manner without compromising your quality production/
profits. The bench top system has a spacious modular design featuring versatility, operational simplicity
and robustness in depth studies of a variety of faults can be conducted using over many applications. Some
examples are rolling element bearing defects, Gear defect, belt and pulley defect, motor bearing defect.
SELECTION OF MATERIAL HANDLING EQUIPMENT FOR FLEXIBLE MANUFACTURING SYSTEM US...ijmech
Material handling equipment plays an important role in the design and development of advance
manufacturing systems (AMS) like flexible manufacturing systems. Material handling equipments affects
the performance and productivity of these advance manufacturing systems. So it becomes very important to
select a right kind of equipment while designing the high end manufacturing systems like FMS. In this
paper an attempt has been made to select the most appropriate material handling equipment for the design
and development of FMS. The proposed model has been build on the basis of material handling attributes
and sub attributes which are critical for material handling equipment selection.
Environmental factors such as air pollution and increase in global warming by using polluting fuels are the most important reasons of using renewable and clean energy that runs in global community. Wind energy is one of the most suitable and widely used kind of renewable energy which had been in consideration so well. This paper introduces an electric power generation
system of wind based on Y-source and improved Y-source inverter to deliver optimal electrical power to the network. This new converter is from impedance source converters family. This presented converter has more degrees of freedom to adjust voltage gain and modulation. Also, by limiting the range of simultaneous control (shooting through) while it maintains the
highest power of maximizer, it can operate in higher modulation range. This causes the reduce of stress in switching and thus it will improve the quality of output. Recommended system had been simulated in MATLAB/Simulink and shown results indicate accurate functionality.
Performance analysis of wind turbine as a distributed generation unit in dist...ijcsit
In this paper, the performance analysis of wind turbine as a distributed generation unit is presented. In this
study a model of wind power is driven by an induction machine. Wind power that is distributed generation
is capable of supplying power to ac power distribution network. Wind power generation system is modeled
and simulated using Matlab Simulink software such that it can be suitable for modeling some kind of
induction generator configurations. To analyze more deeply the performance of the wind turbine system,
both normal and fault conditions scenarios have been applied. Simulation results prove the excellent
performance of the wind power unit under normal and fault conditions in the power distribution system.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
A Hybrid Wind and Hydroelectric Power Production Systemijtsrd
The purpose main purpose of this paper is to study the feasibility of electrification without grid in the Indian subcontinent. The electrical installation will be done with a mixed system that includes Small Hydropower using compensation for water flow, and wind power. Given the climate change that has been observed in regions around the world and believed to be due to the use of conventional energy sources, we must turn our attention to renewable energy sources that are conducive to the future. This paper presents research on the design and simulation of small wind hydro power. After execution, this experimental station will be used primarily to study the potential for hydropower plants to conserve wind power through hydro energy. Indra Pal Singh | Dr. Ravinder Kumar "A Hybrid Wind and Hydroelectric Power Production System" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-6 | Issue-4 , June 2022, URL: https://www.ijtsrd.com/papers/ijtsrd50175.pdf Paper URL: https://www.ijtsrd.com/engineering/electrical-engineering/50175/a-hybrid-wind-and-hydroelectric-power-production-system/indra-pal-singh
Novel control strategy for the global model of wind turbineIJECEIAES
This paper presents a new nonlinear control for the overall model of a three-blade horizontal axis variable speed wind turbine (VSWT) including mechanical and electrical parts, with the aim of improving its performance and making it more profitable. The proposed control is an extension of the classical sliding mode control (SMC) by converting its sliding surface into a sliding sector. The classical SMC approach is widely used for nonlinear systems due to its stability against parameter variation, it is robustness against modeling uncertainties, its good results against external disturbances, and its ease of implementation in real time. Unfortunately, the SMC has a major drawback related to the chattering phenomenon. This phenomenon is due to the utility of a higher switching gain in the case of large uncertainties, it causes high-frequency oscillations once the sliding regime is reached, and it can cause a loss of accuracy by influencing the input control variables. This is the reason that aims to develop a new control law to eliminate the chattering and to guarantee stability, which is demonstrated by the Lyapunov theory. The effectiveness of the developed control is compared with the SMC and is illustrated by numerical simulations using MATLAB toolboxes.
Energy is a fundamental need for industries in every part of the world. The cost of
electricity has increased significantly in the recent years and this trend is expected to continue in the
coming years as well. Ventilation is a key component in the design and execution of all underground
mine operations. Energy-efficient ventilation design is crucial for maintaining safe working
conditions in underground coal or metal mines. Ventilation demand in metal mines may vary
throughout the year, and a careful redesign of the ventilation system can optimize energy costs to a
good extent. This paper investigates the potential for energy savings in underground metal mines by
installing variable frequency drives (VFDs) on the main ventilation fans to provide variable control of
airflow. VFDs are cost-effective, easy to control and require little maintenance. It has been found that
significant amounts of electrical energy can be saved by installing VFDs on the main ventilation fans.
Wind-Driven SEIG Systems: A Comparison StudyCSCJournals
Wind energy is one of the fastest growing renewable energies in the world. This is because it has a much lower environmental impact than conventional energy. In addition, it is one of the lowest-priced renewable energy technologies.
Due to wind speed variation, induction generators are the best choice for such applications. However, they have poor voltage and frequency regulation against wind speed or load variations.
For its operation, the induction generator needs a reasonable amount of reactive power. In stand-alone applications, the reactive power could be supplied to the induction generator by a bank of capacitors as implemented here.
In this paper, simulation of wind turbine driven self excited induction generator (SEIG) has been carried out. Three methods of voltage and frequency regulation have been presented, simulated and analyzed.
The aim of this paper is to compare the three methods from many aspects highlighting the advantages and disadvantages of each one.
Wind Turbine Generator Tied To Grid Using Inverter Techniques and Its DesignsIJSRD
This paper proposes a method of using small sizes WTG of 300W low capacity turbine in small grid channel with inverter techniques. Power can be fed directly to grid by improving durability and eliminating battery usage, using WTG inverter technique. The proposed wind tied with grid by PMG includes boost converter and three phase inverter. For tracking wind speed with variations of wind power MPPT method is used. Interleaving technique is adopted for different frequency variables to improve power capacity. Final result proves WTG helps in improving wind power application as shown in simulation result.
Sizing Optimization of Stand-Alone Wind Power System Using Hybrid Energy Stor...ijsrd.com
In this study, the hydrogen production potential and costs by using wind/electrolysis system were considered. In order to evaluate costs and quantities of produced hydrogen, number of wind-turbines and hub heights are considered as the variable Levelized cost of electricity method was used in order to determine the cost analysis of wind energy and hydrogen production. The results of calculations brought out that the electricity costs of the wind turbines and hydrogen production costs of the electrolyzers are decreased with the increase of turbine hub height. The maximum hydrogen production quantity was obtained 1420KWh/year.
Performance of piezoelectric energy harvester with vortex-induced vibration a...TELKOMNIKA JOURNAL
Piezoelectric energy harvesters (PEHs) are a kind of energy harvester that generates electricity due to pressure or vibration. Vortex-induced vibration (VIV) is a method that utilized wind energy and bluff body to generate the vibration in PEH. The objective of this research was to study the output voltage that generates in different bluff bodies with various airflow velocities. Experimental and simulation have done in this study. Experimental used PEH that consists of piezoelectric bimorph and rectangular-trapezoid fin. Bluff bodies with various cross-sectional areas, namely rhombus, square, and triangle were set up in front of the PEH at a distance of 80 cm. The various air velocities are set up to 5, 7, and 9 m/s in the wind tunnel with a cross-section of 250 mm × 250 mm. The simulation used the finite element method in explore the fluid flow pattern. The rhombus cross-sectional bluff body can generate voltage with an average of 1.5 volts. It is more voltage generated than a square and triangle. A vortex is formed near the rhombus bluff body and generates pressure fluctuation in its wake region. This pressure fluctuation takes place until airflow hits and leads PEH to vibrate and generate the voltage.
Renewable Energy Sources are those energy sources which are not destroyed when their energy is harnessed. Human use of renewable energy requires technologies that harness natural phenomena, such as sunlight, wind, waves, water flow, and biological processes such as anaerobic digestion, biological hydrogen production and geothermal heat. Amongst the above mentioned sources of energy there has been a lot of development in the technology for harnessing energy from the wind.
State of ICS and IoT Cyber Threat Landscape Report 2024 previewPrayukth K V
The IoT and OT threat landscape report has been prepared by the Threat Research Team at Sectrio using data from Sectrio, cyber threat intelligence farming facilities spread across over 85 cities around the world. In addition, Sectrio also runs AI-based advanced threat and payload engagement facilities that serve as sinks to attract and engage sophisticated threat actors, and newer malware including new variants and latent threats that are at an earlier stage of development.
The latest edition of the OT/ICS and IoT security Threat Landscape Report 2024 also covers:
State of global ICS asset and network exposure
Sectoral targets and attacks as well as the cost of ransom
Global APT activity, AI usage, actor and tactic profiles, and implications
Rise in volumes of AI-powered cyberattacks
Major cyber events in 2024
Malware and malicious payload trends
Cyberattack types and targets
Vulnerability exploit attempts on CVEs
Attacks on counties – USA
Expansion of bot farms – how, where, and why
In-depth analysis of the cyber threat landscape across North America, South America, Europe, APAC, and the Middle East
Why are attacks on smart factories rising?
Cyber risk predictions
Axis of attacks – Europe
Systemic attacks in the Middle East
Download the full report from here:
https://sectrio.com/resources/ot-threat-landscape-reports/sectrio-releases-ot-ics-and-iot-security-threat-landscape-report-2024/
Kubernetes & AI - Beauty and the Beast !?! @KCD Istanbul 2024Tobias Schneck
As AI technology is pushing into IT I was wondering myself, as an “infrastructure container kubernetes guy”, how get this fancy AI technology get managed from an infrastructure operational view? Is it possible to apply our lovely cloud native principals as well? What benefit’s both technologies could bring to each other?
Let me take this questions and provide you a short journey through existing deployment models and use cases for AI software. On practical examples, we discuss what cloud/on-premise strategy we may need for applying it to our own infrastructure to get it to work from an enterprise perspective. I want to give an overview about infrastructure requirements and technologies, what could be beneficial or limiting your AI use cases in an enterprise environment. An interactive Demo will give you some insides, what approaches I got already working for real.
Smart TV Buyer Insights Survey 2024 by 91mobiles.pdf91mobiles
91mobiles recently conducted a Smart TV Buyer Insights Survey in which we asked over 3,000 respondents about the TV they own, aspects they look at on a new TV, and their TV buying preferences.
Encryption in Microsoft 365 - ExpertsLive Netherlands 2024Albert Hoitingh
In this session I delve into the encryption technology used in Microsoft 365 and Microsoft Purview. Including the concepts of Customer Key and Double Key Encryption.
Connector Corner: Automate dynamic content and events by pushing a buttonDianaGray10
Here is something new! In our next Connector Corner webinar, we will demonstrate how you can use a single workflow to:
Create a campaign using Mailchimp with merge tags/fields
Send an interactive Slack channel message (using buttons)
Have the message received by managers and peers along with a test email for review
But there’s more:
In a second workflow supporting the same use case, you’ll see:
Your campaign sent to target colleagues for approval
If the “Approve” button is clicked, a Jira/Zendesk ticket is created for the marketing design team
But—if the “Reject” button is pushed, colleagues will be alerted via Slack message
Join us to learn more about this new, human-in-the-loop capability, brought to you by Integration Service connectors.
And...
Speakers:
Akshay Agnihotri, Product Manager
Charlie Greenberg, Host
Key Trends Shaping the Future of Infrastructure.pdfCheryl Hung
Keynote at DIGIT West Expo, Glasgow on 29 May 2024.
Cheryl Hung, ochery.com
Sr Director, Infrastructure Ecosystem, Arm.
The key trends across hardware, cloud and open-source; exploring how these areas are likely to mature and develop over the short and long-term, and then considering how organisations can position themselves to adapt and thrive.
Generating a custom Ruby SDK for your web service or Rails API using Smithyg2nightmarescribd
Have you ever wanted a Ruby client API to communicate with your web service? Smithy is a protocol-agnostic language for defining services and SDKs. Smithy Ruby is an implementation of Smithy that generates a Ruby SDK using a Smithy model. In this talk, we will explore Smithy and Smithy Ruby to learn how to generate custom feature-rich SDKs that can communicate with any web service, such as a Rails JSON API.
Neuro-symbolic is not enough, we need neuro-*semantic*Frank van Harmelen
Neuro-symbolic (NeSy) AI is on the rise. However, simply machine learning on just any symbolic structure is not sufficient to really harvest the gains of NeSy. These will only be gained when the symbolic structures have an actual semantics. I give an operational definition of semantics as “predictable inference”.
All of this illustrated with link prediction over knowledge graphs, but the argument is general.
Securing your Kubernetes cluster_ a step-by-step guide to success !KatiaHIMEUR1
Today, after several years of existence, an extremely active community and an ultra-dynamic ecosystem, Kubernetes has established itself as the de facto standard in container orchestration. Thanks to a wide range of managed services, it has never been so easy to set up a ready-to-use Kubernetes cluster.
However, this ease of use means that the subject of security in Kubernetes is often left for later, or even neglected. This exposes companies to significant risks.
In this talk, I'll show you step-by-step how to secure your Kubernetes cluster for greater peace of mind and reliability.
AI for Every Business: Unlocking Your Product's Universal Potential by VP of ...
Airfoil linear wind generator (alwg) as a novel wind energy extraction approach
1. International Journal of Recent advances in Mechanical Engineering (IJMECH) Vol.3, No.4, November 2014
DOI : 10.14810/ijmech.2014.3406 51
AIRFOIL LINEAR WIND GENERATOR (ALWG): AS A
NOVEL WIND ENERGY EXTRACTION APPROACH
Hossein Darijani1
and Abbas Panahi2
1,2
Department of Mechanical Engineering, College of Engineering, Shahid
Bahonar University of Kerman, Kerman, Iran
ABSTRACT
Linear wind generator (LWG) is a sufficient way of wind energy harnessing process. However, complicated
LWG energy extraction mechanism such as complex system for transferring linear motion to rotational
motion and problems related to changing the angle of attack is resulted to energy dissipation. In the other
hand the linear generator that delivers ocean wave energy to electricity has been developed as a new
renewable energy extraction method. Some of the problems associated with this technology are corrosion,
high cost of manufacturing, high requirement for installation and construction, economical consideration,
etc. In the most recent works, low dissipation energy in mechanism, low cost, simplicity and high
performance are highly regarded as environmentally friendly methods for wind energy extraction
mechanisms. In the current study, we would like to introduce a new and efficient method to extract wind
energy using airfoil linear wind generator(ALWG). ALWG is a new method that produces liner
reciprocating motion via attached airfoils to a mover in a magnetic field in order to generate electricity.
The most important advantage of ALWG is its simplicity and its compatibility to all wind situations that can
be more controllable relative to ocean-based and also relative to LWG that become challengeable problem.
KEYWORDS
Keywords: ALWG, Airfoil, Linear Generator, Wind Energy
1. INTRODUCTION
An urgent and strategic issue of our society is the solution of the atmosphere pollution problems
which posed by electric energy generation from fossil flues as nonrenewable sources [1].
Obviously, these problems can be resolved by the use of natural sources that are renewable,
cheap, easily available and sustainable for the environment. However, the actual renewable
technologies up to now had not such potentials. As a result, many attempts have been conducted
in order to utilize wind [2], ocean wave [3], solar [4], etc. as green energy sources. One of the
most well-known examples is wind mills or wind turbine that is used as a realistic approach to
harness wind energy in great amount. Wind farms have problems of land occupation and
environmental impact because of this fact that their electrical production depend on the amount of
area that they occupy [5]. To overcome these problems, Milanese et al. has developed a new class
of wind energy generators, named “Kitegen” as shown in Figure 1, [6, 7].
2. International Journal of Recent advances in Mechanical Engineering (IJMECH) Vol.3, No.4, November 2014
52
Figure 1. The mechanism of operation of kite generator
There are many obstacles in front of Kitegen project development, due to the main problems that
wind has created for controlling the trajectory of kite and its stability [8]. Up to now, there are
rare methods to utilize this project efficiently. Consequently, there is much consideration on
Kitegen project in the recent years in order to extract wind energy using this method practically.
For example, Laddermill [9] with similar situations to Kitegen is one of the used technologies. In
the Laddermill structure there are many kites which are connected to a main rode that is twisted
around an attached drum to generator (Figure 2).
Figure 2. The structure of a Laddermill
Another important approach which has been introduced based on Kitegen operation principle, is
linear wind generator (LWG). The LWG can convert an equivalent swept area of wind compared
to wind turbine generator (WTG) into twice the amount of electricity. Also, it is simple to install
and can produce electricity at a substantially lower cost and within a significantly smaller land
area compared to WTGs.
To introduce the LWG operation its principle is demonstrated in Figure 3.
3. International Journal of Recent advances in Mechanical Engineering (IJMECH) Vol.3, No.4, November 2014
53
Figure 3. The principle of action of a LWG
As shown in Fig.3, first, air passing over the initial stage blades to produce a lift force. The air
velocity, after passing the first stage, is reduced significantly and requires the second stage blades
to be angled appropriately because of the changed apparent wind vector. The second stage blades
also produce a lift force component in the direction of cable travel thereby adding to the first
stage’s contribution; by this way the most amount of winds energy have been harnessed .
As you can see in the LWG operation mechanism, it suffers from a complicated energy extraction
process due to a complex system for transferring linear motion to rotational motion. Furthermore,
it has problems originated from changing the angle of attack which are resulted to the energy
dissipation and system life reduction.
One of the newest ideas is the use of linear generator (LG) to convert ocean wave energy to
electricity [10]. The simple structure of a LG for energy extraction from ocean is shown in Figure
4.
Figure 4. The main structure of an ocean wave energy generator
Although the energy extraction from ocean ,[11], is interesting and can be used for special
applications, however it suffer from some drawbacks such as corrosion, high cost of
manufacturing, high requirement for installation and construction, economical consideration, etc.
[12] . Nowadays, some modifications to already existing methodologies to renewable energy
extraction, considering the environmental consciousness in both industrial and academic studies,
have received great attention. Along this line, herein, we introduce a new mechanism (Figure 5)
4. International Journal of Recent advances in Mechanical Engineering (IJMECH) Vol.3, No.4, November 2014
54
based on aerodynamic forces exerts on airfoil by air current. In this method we used from linear
generator instead of rotary generator. Overall, in our protocol the lock-unlock mechanisms and
angle of attack changer is eliminated in order to save energy by use of a flywheel and change of
angleof attack only.
Figure 5. Overall picture of an ALWG
2.1. The structure and mechanism of AWLG
The main structure of a designed AWLG is depicted in Figure 6.
Figure 6. The main components of ALWG and its operation
As shown in Fig. 6, an AWLG contains 3 substructures: 1) a set of airfoils, 2) linear generator and
3) a device for saving energy (flywheel or spring). In AWLG, in first cycle the angle of attack of
airfoil will be changed in order to exert an upward force on airfoil. While the airfoil reaches to the
maximum level in the vertical path, simultaneously the flywheel is saving fraction of the energy.
After this process the flywheel operates and complete the other cycle. Taking into account the
fact that airfoil is on a beam, a reciprocating motion will be produce in perpendicular direction
relative to wind. Considering this issue that radial and axial force occur in the linear generator
(between rotor and stator, this force is due to the geometrical magnetic anisotropy of the
5. International Journal of Recent advances in Mechanical Engineering (IJMECH) Vol.3, No.4, November 2014
55
generator), the existence of flywheel is necessary in order to maintain continues motion and
homogenize anisotropy forces [13]. In the second cycle (operation of flywheel), the changer of
angle of attack mechanism can deplete it to minimum level. This action decrease the lift force on
the airfoil to zero as it reaches to minimum length relative to generator. Affected by this actionthe
flux in the stator coils varies with the mover position from maximum to minimum. Consequently,
an AC motion-induced voltage is produced in the stator coil as a result of up-and-down
oscillatory motion of the mover.
2.2. Conservation of energy
The magnetic flux (φ) can be determined using the following equation (Eq. 1) in the presence of
a magnetic field (B):
∅ = න .ܤ ݀ܽԦ
(1)
Also, to determine the electromotance, in the presence of a magnetic field the Faraday induction
low is used (Eq. 2). (For more study [14])
݁ = −
݀ሺܰ∅ሻ
݀ݐ
(2)
According to this equation the electromotance (voltage) induced in a close circuit are equal minus
the time derivation of total flux enclosed by the circuit. The minus sign is confirmed that the
direction of the current induced in the circuit is opposed to the direction of increasing flux.
The mechanism of operation of linear actuator according to the equations 1 and 2 is shown in
Figure 7, which is the principle of a linear generator in reverse manner.
Figure 7. The principle of operation of linear generator & actuator
Because the electromechanical energy conversion process is reversible, actuators can be operated
as linear electric generators, in which case mechanical energy is transformed into electric energy.
The fundamental energy conversion equation is demonstrated in Eq. 3.
ݔܨሶ = ܸܫ (3)
Where F is mechanical force, N; dx/dt is mechanical velocity m/s; V is voltage, and I is current. It
is assumed that F and x are in the same direction.
6. International Journal of Recent advances in Mechanical Engineering (IJMECH) Vol.3, No.4, November 2014
56
When the stator coil is fed with an electric current, the ferromagnetic translator is pulled into the
air gap (between the stator poles) until, for x = 0, the force becomes zero. At x = 0 all the flux
lines ideally become vertical (aligned flux position) and the stored energy in the magnetic field is
minimal. Now, if the current is turned off, the mechanical spring pulls the translator out from the
air gap to x = -l/2 position. At this position the current is turned on again. Sustained oscillations
obtain. This mechanism explain the work of linear actuator ,but it is practical that we reverse the
mechanism in order to getting electricity by enforce mover to experience a reciprocating motion
.We do this work by means of lift force that has been accomplished by an airfoil [14] .
2.3. Mathematical modeling of motion of airfoil
Figure 8 schematically shows an airfoil installed in wind direction.
Figure 8. The mathematical modeling of an airfoil motion
It is assumed that the airfoil can move only vertically. The displacement of the center of mass is z
and it is positive when going upward. The wind is blowing at uniform horizontal of speed u.
When the airfoil moves upward at a speed of v the surrounding air moves downward relative to
the airfoil at the same speed. To the oncoming air flow, the angle of attack of the airfoil can be
obtained by use of the following equation:
ߙ = ߙ + ݊ܽݐିଵ
ቀ
ݒ
ݑ
ቁ (4)
In absence of wind the angle of attack of airfoil is ߙ and after that airfoil senses wind the angle
of attack increases as amount of ݊ܽݐିଵ
ሺ
௩
௨
ሻ.
The lift of the airfoil in the direction normal to the flow has the expression as:
ܮ =
1
2
ߩሺݑଶ
+ ݒଶሻ݈ܵܥ
(5)
Where ߩ is air density, S the projected area of airfoil, and CL is the lift coefficient of the airfoil.
The lift coefficient increases by enhancement of the angle of attack up to stall point. It should be
mentioned that the angle of attack will be reduced, if the rising of angle of attack continue. The
curve of CL versus angle of attack is shown in Figure 9.
7. International Journal of Recent advances in Mechanical Engineering (IJMEC
Figure 9. Lift coefficient (C
In this study the thin airfoil theory is used in which lift coefficient has a linear relation with angle
of attack (Eq. 6).
ܥ = 2ߨߙ
It is necessary to avoid very high angle of attack due to the effect of induced drag that cause
exerting an undesirable force in direction of air flow. In high angle of attack, the linear generator
may experience unfavorable input and this can effects on b
motion on it (Fig. 5). Consequently,
More importantly, 'vortex' is an imperative point that could exist when aspect ratio (AR) is
finite. Vortex causes some circulation behind of the airfoil
top and below of the airfoil, that all together cause low effective angle of attack relative to airfoil
section with infinite aspect ratio (AR=
drag force and induced drag as two main factors in structure designing.
The equations of motion for the center of mass are:
݀ݖ
݀ݐ
= ݉ ݀݊ܽ ݒ
݀ݒ
݀ݐ
= −
Upon substitution of the value ܿݏ
݉
݀ݒ
݀ݐ
= −݉݃ − ݂௫ + ߨߩܵ
In which m is the sum of mass of airfoil and rotor ( considered 5 Kg ) ,u is velocity of wind,
velocity of mover,݂௫is axial force due to the effect of geometrical magnetic anisotropy of the
generator ,ߙ is initial angle of attack ,S is projected area of airfoil .
By considering the fact that electrical power plus losses in generator
current… etc. is equal the mechanical power, so we determined its value as follow:
ܲ = ܸܨ
International Journal of Recent advances in Mechanical Engineering (IJMECH) Vol.3, No.4, November 2014
Figure 9. Lift coefficient (CL) versus angle of attack (α)
In this study the thin airfoil theory is used in which lift coefficient has a linear relation with angle
It is necessary to avoid very high angle of attack due to the effect of induced drag that cause
exerting an undesirable force in direction of air flow. In high angle of attack, the linear generator
may experience unfavorable input and this can effects on beam that airfoil has a reciprocating
motion on it (Fig. 5). Consequently, α should be selected in a certain range in order to avoid stall.
More importantly, 'vortex' is an imperative point that could exist when aspect ratio (AR) is
ortex causes some circulation behind of the airfoil, unbalanced pressure distribution on
top and below of the airfoil, that all together cause low effective angle of attack relative to airfoil
section with infinite aspect ratio (AR=∞). In this work for simplicity we ignored the effects of
drag force and induced drag as two main factors in structure designing.
The equations of motion for the center of mass are:
−݉݃ + ݏܿܮሺ∆ߙሻ − ݂௫
ܿߙ∆ݏ =
௨
√௨మା௩మ
and L, the second equation becomes:
ߨߩܵ ݑ ቆߙ + ݊ܽݐିଵ
ቀ
ݒ
ݑ
ቁቇ ඥݑଶ + ݒଶ
In which m is the sum of mass of airfoil and rotor ( considered 5 Kg ) ,u is velocity of wind,
is axial force due to the effect of geometrical magnetic anisotropy of the
is initial angle of attack ,S is projected area of airfoil .
By considering the fact that electrical power plus losses in generator due to hysteresis, iron, eddy
etc. is equal the mechanical power, so we determined its value as follow:
H) Vol.3, No.4, November 2014
57
In this study the thin airfoil theory is used in which lift coefficient has a linear relation with angle
(6)
It is necessary to avoid very high angle of attack due to the effect of induced drag that cause
exerting an undesirable force in direction of air flow. In high angle of attack, the linear generator
eam that airfoil has a reciprocating
should be selected in a certain range in order to avoid stall.
More importantly, 'vortex' is an imperative point that could exist when aspect ratio (AR) is
, unbalanced pressure distribution on
top and below of the airfoil, that all together cause low effective angle of attack relative to airfoil
work for simplicity we ignored the effects of
(7)
and L, the second equation becomes:
(8)
In which m is the sum of mass of airfoil and rotor ( considered 5 Kg ) ,u is velocity of wind, ݒ is
is axial force due to the effect of geometrical magnetic anisotropy of the
due to hysteresis, iron, eddy
(9)
8. International Journal of Recent advances in Mechanical Engineering (IJMECH) Vol.3, No.4, November 2014
58
By substituting (8) into (9) following equation will be obtained:
ܲ = ቆ−݉݃ − ݂௫ + ߨߩܵ ݑ ቆߙ + ݊ܽݐିଵ
ቀ
ݒ
ݑ
ቁቇ ඥݑଶ + ݒଶቇ ݒ
(10)
And also eq. 11 is as follow:
ܲ =
ܸଶ
ܴ
(11)
In Eq. 11 R is the equivalent resistant in circuit which depends on the generator and also electrical
properties of stator and rotor which is considered its value a constant. Figure (10) shows
schematically a lumped circuit equivalent of the generator can be used to understand how the
current in generator is related to induced electromotance.
Figure 10 : Lumped circuit equivalent of a synchronous generator
The circuit equivalent is only an approximation but is useful for pedagogical reasons. Figure (10)
shows the equivalence of a generator where the measurable voltage is described by an
electromotance Enl .This voltage is referred to no load voltage, which is the measurable voltage at
the coil ends when no current flows through the generator’s is the reactance of the generator .Rc
is the resistance in the coil windings .The outer circuit, or the load, can be either purely resistive
or reactive. In this work the load is assumed to be strictly resistive and is described by a resistance
RloadThe voltage over the load U will thus be in phase with the armature current Ia.
2.4 Power losses
The power losses in a generator consist of three parts:
1. Losses due to the changing magnetic field (often referred to steel losses)
2. Resistive losses in the coil windings
3. Mechanical losses such as friction and deformation.
The main part of these losses happen in the stator steel .It consists of two parts: hysteresis losses
and losses due to eddy currents.
9. International Journal of Recent advances in Mechanical Engineering (IJMECH) Vol.3, No.4, November 2014
59
2.4.1 Hysteresis losses
Hysteresis losses is the energy it takes to reverse the magnetization of the material and will only
effect materials that are magnetic dipoles .The losses are approximately proportional to the
frequency of the magnetic field and the acquirer of the magnetic induction and per unit volume is
as follows:
ܲ = ܥܤଶ
݂ (12)
Where Ch is a material dependent constant. Hysteresis losses can be reduced by selecting a
material with soft magnetic properties i.e. a material that is easily re-magnetized hysteresis.
2.4.2 Eddy current losses
Eddy currents are circular electric current in a material by the changing magnetic field. These
current are directly proportional to the electromotance induced in circuit by changing magnetic
flux. And the power losses per unit volume is proportional to the square of current as follow:
ܲா = ܥா
1
ܶ
න ൬
߲ܤ
߲ݐ
൰
ଶ
≈ ܥாܤଶ
݂ଶ
்
(13)
CE is a material constant depending on the resistivity and T is the time of one period .The major
part of eddy losses appear in stator and can be depleted by assembling them with electric isolated
lamination of the stator steel.
2.4.3 Resistive losses
The resistive losses in the coil windings are referred to as copper losses because the conductor in
most cases are made of copper. Since copper is not a magnetic dipole material hysteresis losses
will not appear. The resistive losses in a conductor with electrical resistance R caring current I
are:
ܲ = ܫଶ
ܴ (14)
Table 1. The value of wasted powers in a considered linear generator
Hysteresis (KW) 0.52
Eddy current losses (KW) 0.07
Rotational losses (KW) 0.03
Total iron losses (KW) 0.62
In the Eq.15 the principle of conservation of energy is mentioned, that explain the relation
between electrical energy and mechanical energy and also their relevant losses.
P(mechanical)+P(friction-loss)=P(electrical)+P(Copper, iron,… losses) (15)
By substituting (eq. 10) into (eq. 11) and by use of (eq. 15) and also ignoring the amount of losses
(because estimating the maximum energy output of this mechanism is regarded). As a result the
following equation is obtained.
10. International Journal of Recent advances in Mechanical Engineering (IJMECH) Vol.3, No.4, November 2014
60
ܸ = ඨܴ ቆ−݉݃ − ݂௫ + ߨߩܵ ݑ ቆߙ + ݊ܽݐିଵ ቀ
ݒ
ݑ
ቁቇ ඥݑଶ + ݒଶቇ ݒ (16)
After plotting P (power) versus mover velocity, this shows that mechanical power increase
dramatically as velocity increases slightly (Figure 11).
Figure 11: The increment of pure mechanical power versus velocity of mover
It is possible to use several airfoils vertically but what is important here is the distance between
the used airfoils. From aerodynamic point of view when air passes on the airfoil, it changes the
stream shape and makes a disturbance in the vicinity around airfoil. This function affects the
pressure distribution around upper or lower airfoil and generally causes depletion in lift force of
them. We supposed that there is no limitation on installing airfoils which have been arranged in a
logical manner that causes no bad effect on the other airfoil. By this way the mechanical power
that has extracted increase dramatically.
Equation 16 is a relation that shows Induced-voltage versus velocity of mover. It should be
considered that velocity can be instantaneous or constant. In the following the induced voltage
and mechanical power for some condition are illustrated.
3. Results and discussions
The mechanical power was plotted versus velocity of mover as depicted in Figure 12.
11. International Journal of Recent advances in Mechanical Engineering (IJMECH) Vol.3, No.4, November 2014
61
Figure 12. Power versus mover velocity in different wind condition
As shown in Fig. 12 by increasing the wind velocity the amount of mechanical power is increased
dramatically.
In other attempt, we investigate the effect of projected area on mechanical power for u=10 m/s.
The diagram of this investigation is shown in Figure 13.
Figure 13. Power versus mover velocity in different value of projected area
Figure 12 show that by increasing the projected area (S) the mechanical power is increased. You
can see that the effect of this parameter is more than wind velocity so that in same velocity of
mover the power output become 3 times greater than the its amount in figure 12.
Other important factor to increase the mechanical power is initial angle of attack. As shown in
Figure 14 the mechanical power is increased with addition of initial angle of attack. For example
for 1 m/s velocity of mover, 10 m/s velocity of wind and initial angle of attacks 10, 14 and 16 the
mechanical power were calculated 6, 7 and 8 KW respectively.
12. International Journal of Recent advances in Mechanical Engineering (IJMECH) Vol.3, No.4, November 2014
62
Figure 14. Power versus mover velocity in different initial angle of attack
Our studies on the effect of number of airfoil on mechanical power showed that this parameter
has significant influence on power output.
Figure 14. Power versus mover velocity for 20, 30 and 40 number of airfoils
As shown in Figure 14, at a certain velocity of mover when the numbers of airfoils increase twice
the power become 7 times approximately. This is very interesting point because we can improve
the power output in huge amount using only manipulation the number of airfoils.
Next we evaluated the effect of wind velocity, projection area, and initial angle of attack on the
overall induced-voltage in the main circuit of system. The results demonstrated that by increment
of wind velocity the output voltage enhance (Figure 15).
13. International Journal of Recent advances in Mechanical Engineering (IJMECH) Vol.3, No.4, November 2014
63
Figure 15. Induced-voltage versus mover velocity in different wind condition
As shown in Figure 15, when the wind velocity changed from 10 m/s to 15 m/s the voltage
become twice. Effect of projected area on voltage is shown in Figure 16.
Figure 16. Induced-voltage versus mover velocity in different projected area
Figure 16 shows that by increase of projection area the voltage is increased so that at u = 10 m/s
when S raise from 1 to 3 voltage change from 350v to 750 v.
Also by increment of initial angle of attack the overall induced-voltage is increased. As shown in
Fig. 17, by enhancement of alpha from 10 to 16 at a specific wind velocity the output voltage
becomes twice approximately.
14. International Journal of Recent advances in Mechanical Engineering (IJMECH) Vol.3, No.4, November 2014
64
Figure 17. Induced-voltage versus mover velocity for different initial angle of attack
Furthermore, Figure 18 shows the value of mechanical power and velocity of mover in same
time, confirming that with past of time these parameters enhance in same manner. This diagram
demonstrated that with increment of time that is same to increase the amplitude of oscillation of
mover, the power output will increase too.
Figure 18 .Value of mechanical power and velocity of mover in same time
3.1. A comparison between ALWG and ocean wave energy
The total energy in an ocean wave can be calculated in joules per unit of width of wave front by
summing up the potential and kinetic energy of all waves together [15]. The potential energy in a
wave of length L is generated by the displacement of the water away from the mean sea level. The
kinetic energy of a wave is a result of both horizontal and vertical water particle motions [16].
The total potential and kinetic energy of an ocean wave can be expressed as:
15. International Journal of Recent advances in Mechanical Engineering (IJMECH) Vol.3, No.4, November 2014
65
ܧ =
1
2
ߩ݃ܣଶ
(18)
Where g =9.8 m/s2
and ρ is density of water (1000 Kg/m3
) and A is wave amplitude. To obtain
the average energy flux or power of a wave period, energy is multiplied by the speed of wave
propagation, Vp:
ܸ =
ܮ
2ܶ
(19)
Where T is the wave period (s) and L is wavelength (m) [18]:
ܲݓ =
1
2
ߩ݃ܣଶ
ܮ
2ܶ
(20)
And by following relation L and T are related:
ܮ =
݃ܶଶ
2ߨ
(21)
So the final relation will be:
ܲݓ =
ߩ݃ଶ
ܶܣଶ
8ߨ
=
ߩ݃ଶ
ܶܪଶ
32ߨ
(22)
Where H is the height of wave and A is amplitude (H=2A).
In the Figure 19, there is a comparison between the total power of a wave and an AWLG in same
condition. This point has been shown that for the 20 number of airfoil arrangement, the power is
approximately same, of course not for very high value of mover velocity (Table 1).
Table 1. A numerical comparison between ALWG and ocean wave energy
V =H/2T Wave energy (W) 20 airfoil (W) 35 airfoil (W)
H (m) V (m/s)
1 0.125 1000 2000 6000
2 0.25 8000 5000 10000
3 0.375 15000 9000 18000
4 0.5 30000 15000 25000
16. International Journal of Recent advances in Mechanical Engineering (IJMECH) Vol.3, No.4, November 2014
66
Figure 19. A comparison between the total power of a wave and an AWLG in same condition
a) 10 airfoil b) 20 airfoil c) 30airfoil d) 40 airfoil
Conclusion
This work has disclosed a study intended to scrutinize airfoil linear wind generator (ALWG) as a
new class of wind energy extractor, talented to overcome the main limitations of the present wind
energy extractor technologies. Moreover, ALWG has introduced in order to eliminate some of the
problems associated with the previous extractor systems such as LWG and ocean-based systems.
In fact, ALWG is a new method to produces liner reciprocating motion via attached airfoils to a
mover in a linear generator in order to generate electricity.Herein, we have introduced a new
mechanism (Figure 5) based on aerodynamic forces exerts on airfoil by air current. In this method
we used from linear generator instead of rotary generator. Overall, in our protocol the lock-unlock
mechanisms and angle of attack changer is eliminated in order to save energy by use of a
flywheel and change of angleof attack only.
Our study shows that in a certain velocity of mover: 1) increasing the projected area of airfoil has
a considerable effect on mechanical power and also on induced voltage of generator 2) the
mechanical power and induced voltage of generator are increased with addition of initial angle of
attack; 3) wind velocity is a contributory factor but its influence is not more higher than
increasing projected area and initial angle of attack thus the extraction of more energy from wind
is practical using an appropriate design of airfoils in the absence of high wind velocity; 4) the
power will be increased dramatically by increasing the number of airfoils.
Acknowledgment
We gratefully acknowledge Zarand power generation Management Company under management
of Mr. Heidary for partial support of this work. Also, we are thankful to Prof. Mansoori and Prof.
Ameri in Mechanical Engineering Department of Shahid Bahonar University for their helpful
comments.
17. International Journal of Recent advances in Mechanical Engineering (IJMEC
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Authors
Hossein Darijani received the BSc degree in mechanical engineering from Shahid Bahonar
University of Kerman. He received the MSc and PhD, both in mec
Sharif University of Technology (SUT). His technical interestsare Nonlinear Continuum
Mechanic Constitutive Modelling of Hyperelastic Materials Non
Deformation Thermoelasticity Plasticity. Now, he is assi
University of Kerman.
Abbas Panahi was born in January 21nd 1992,in Shiraz. He received his BSc degree in
mechanical engineering from Shahid Bahonar University of Kerman. His research interests
are computational nanotechnology, Atomistic simulation (molecular dynamic),
mechanic and renewable energy systems (wind, solar).
International Journal of Recent advances in Mechanical Engineering (IJMECH) Vol.3, No.4, November 2014
Chen D, Xinhui Bi, Jinping Zhao, Laiguo Chen, Jihua Tan, Bixian Mai, Guoying Sheng, Jiamo Fu,
Minghung Wong Pollution characterization and diurnal variation of PBDEs in the atmosphere of an
waste dismantling region, Environmental Pollution, Volume 157, Issue 3, March 2009, Pages 1051
A reviewontheperformanceofSavoniuswind turbines Renewable and Sustainable Energy Reviews,
Volume 16, Issue 5, June 2012, Pages 3054-3064-João Vicente Akwa, Horácio Antonio Vielmo,
energy extraction' Johannes Falnes, Marine Structures 20 (2007) 185
economicanalysisof solardistillationsystems: A review Renewable and
Sustainable Energy Reviews, Volume 27, November 2013, Pages 709-723
M.Canale, L. Fagiano,M. Milanese, 'Kitegen: A revolution in wind energy generation '
Ippolito M. Smart control system exploiting the characteristics of generic kites or airfoils to convert
ean patent # 02840646, 2004.
Milanese M, Ippolito M. Sistema e procedimento di controllo automatico Del volo di pro
Potenza. Patent no. TO2006A000372, 2006 [in Italian]
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Energy, Volume36, Issue10, Octobe, 2011, Pages2667-2678 George M. Dadd, Dominic A. Hudson,
Laddermill, a novel concept to exploit the energy in theairspace Aircraft Design, Volume4, Issues2
Pages81-97Wubbo J. Ockel
Historical Aspects of wave energy conversion, Comprehensive Renewable Energy, Volume 8, 2012,
Energy harvesting (solar, wind and ocean energy conversion system),Alireza khaligh, OmerC.onar,
national Standard Book Number: 978-1-4398-1508-3
Design of a linear generator for wave energy plant, O.Danielsson, Upssala University Sweden
Constantin GHITA,Aurel Iounut CHIRILA,Ioan Dragos DEACONU, and Daniel Ion ILINA,'The
a linear generator used to obtain electrical energy from waves energy '
Department of Electrical Engineering Politehnica University of Bucharest
Linear Electrical actuators and Generators, by I.Boldea (Polytechnic Institute, Timisoara, Romania)
Syed A.Nasar (university of Kentucky)
Energy harvesting (solar, wind and ocean energy conversion system),Alireza khaligh, Omer Conar,
International Standard Book Number: 978-1-4398-1508-3
G.T. Heydt, “An assessment of ocean thermal energy conversion as an advanced electric Generation
methodology,” Proceedings of the IEEE, 81, 409–418, 1993
Hossein Darijani received the BSc degree in mechanical engineering from Shahid Bahonar
University of Kerman. He received the MSc and PhD, both in mechanical engineering, from
Sharif University of Technology (SUT). His technical interestsare Nonlinear Continuum
Mechanic Constitutive Modelling of Hyperelastic Materials Non-Linear elasticity Finite
Deformation Thermoelasticity Plasticity. Now, he is assistant professor in Shahid Bahonar
was born in January 21nd 1992,in Shiraz. He received his BSc degree in
mechanical engineering from Shahid Bahonar University of Kerman. His research interests
nanotechnology, Atomistic simulation (molecular dynamic), fluid
energy systems (wind, solar).
H) Vol.3, No.4, November 2014
67
Chen D, Xinhui Bi, Jinping Zhao, Laiguo Chen, Jihua Tan, Bixian Mai, Guoying Sheng, Jiamo Fu,
Minghung Wong Pollution characterization and diurnal variation of PBDEs in the atmosphere of an
3, March 2009, Pages 1051-
A reviewontheperformanceofSavoniuswind turbines Renewable and Sustainable Energy Reviews,
João Vicente Akwa, Horácio Antonio Vielmo,
energy extraction' Johannes Falnes, Marine Structures 20 (2007) 185–201
economicanalysisof solardistillationsystems: A review Renewable and
M.Canale, L. Fagiano,M. Milanese, 'Kitegen: A revolution in wind energy generation '-Journal of
Ippolito M. Smart control system exploiting the characteristics of generic kites or airfoils to convert
Milanese M, Ippolito M. Sistema e procedimento di controllo automatico Del volo di profili alari di
forshippropulsion Renewable
2678 George M. Dadd, Dominic A. Hudson,
Laddermill, a novel concept to exploit the energy in theairspace Aircraft Design, Volume4, Issues2–3,
Historical Aspects of wave energy conversion, Comprehensive Renewable Energy, Volume 8, 2012,
Energy harvesting (solar, wind and ocean energy conversion system),Alireza khaligh, OmerC.onar,
Design of a linear generator for wave energy plant, O.Danielsson, Upssala University Sweden
Constantin GHITA,Aurel Iounut CHIRILA,Ioan Dragos DEACONU, and Daniel Ion ILINA,'The
a linear generator used to obtain electrical energy from waves energy '-
Linear Electrical actuators and Generators, by I.Boldea (Polytechnic Institute, Timisoara, Romania)
Energy harvesting (solar, wind and ocean energy conversion system),Alireza khaligh, Omer Conar,
ion as an advanced electric Generation
was born in January 21nd 1992,in Shiraz. He received his BSc degree in
mechanical engineering from Shahid Bahonar University of Kerman. His research interests
fluid