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International Journal of Engineering Science and Technology , 2012,
Abstract: The depleting fossil fuel reserves and increasing concern towards global warming have created the need to surge for the alternative power generation options. Renewable energy sources like Wind, Solar-PV, Biomass and fuel cells are gaining prominence nowadays, as they are more energy efficient, reduce pollution and also they serveas a promising solution to the toughest energy crisis faced during the recent years. This paper focuses on the modeling and simulation of solar – photovoltaic, wind and fuel cell hybrid energy systems using MATLAB/Simulink software. The intermittent nature of solar and wind energy sources make them unreliable. Hence Maximum Power Point Tracking (MPPT) is used to extract maximum power from the wind and sunwhen it is available. The standard perturb and observe method of MPPT is used for the PV system and for the wind generation system. The simulation results of the PV/Wind /Fuel cell hybrid system are presented in graph showing the effectiveness of the proposed system model. Also, hardware implementation of microcontroller based MPPT for solar-PV alone and unit sizing of the hybrid system for the PG simulation lab in EEE Dept. of Thiagarajar College of Engineering is depicted in the paper.
Simulation of Dynamic Response of Small Wind-Photovoltaic-Fuel Cell Hybrid Energy System  [PDF]
Saeid Esmaeili, Mehdi Shafiee
Smart Grid and Renewable Energy (SGRE) , 2012, DOI: 10.4236/sgre.2012.33027
Abstract: Renewable energy systems are of importance as being modular, nature-friendly and domestic. Among renewable energy systems, a great deal of research has been conducted especially on photovoltaic effect, wind energy and fuel cell in the recent years. This paper describes dynamic modeling and simulation results of a small wind-photovoltaic-fuel cell hybrid energy system. The hybrid system consists of a 500 W wind turbine, a photovoltaic, a proton exchange membrane fuel cell (PEMFC), ultracapacitors, an electrolyzer, a boost converter, controllers and a power converter that simulated using MATLAB solver. This kind of hybrid system is completely stand-alone, reliable and has high efficiency. In order to minimize sudden variations in voltage magnitude ultracapacitors are proposed. Power converter and inverter are used to produce ac output power. Dynamics of fuel-cell component such as double layer capacitance are also taken into account. Control scheme of fuel-cell flow controller and voltage regulators are based on PID controllers. Dynamic responses of the system for a step change in the electrical load and wind speed are presented. Results showed that the ability of the system in adapting itself to sudden changes and new conditions. Combination of PV and wind renewable sources is made the advantage of using this system in regions which have higher wind speeds in the seasons that suffers from less sunny days and vice versa.
Modeling, Control, and Simulation of a Solar Hydrogen/Fuel Cell Hybrid Energy System for Grid-Connected Applications  [PDF]
Tourkia Lajnef,Slim Abid,Anis Ammous
Advances in Power Electronics , 2013, DOI: 10.1155/2013/352765
Abstract: Different energy sources and converters need to be integrated with each other for extended usage of alternative energy, in order to meet sustained load demands during various weather conditions. The objective of this paper is to associate photovoltaic generators, fuel cells, and electrolysers. Here, to sustain the power demand and solve the energy storage problem, electrical energy can be stored in the form of hydrogen. By using an electrolyser, hydrogen can be generated and stored for future use. The hydrogen produced by the electrolyser using PV power is used in the FC system and acts as an energy buffer. Thus, the effects of reduction and even the absence of the available power from the PV system can be easily tackled. Modeling and simulations are performed using MATLAB/Simulink and SimPowerSystems packages and results are presented to verify the effectiveness of the proposed system. 1. Introduction At present, most of energy demand in the world relies on fossil fuels such as petroleum, coal, and natural gas that are being exhausted very fast. One of the major severe problems of global warming is one of these fuels combustion products, carbon dioxide; these are resulting in great danger for life on our planet [1]. Fossil fuels can have as an alternative some renewable energy sources like solar, wind, biomass, and so; among them on the photovoltaic (PV) generator which converts the solar radiation into electricity, largely used in low power applications. The photovoltaic generator is chosen for its positive points including being carbon free and inexhaustible; moreover, it does not cause noise for it is without moving parts and with size-independent electric conversion efficiency [2]. Nevertheless, the power generated by a PV system is influenced by weather conditions; for example, at night or in cloudy periods, it would not generate any power or application. In addition, it is difficult to store the power generated by a PV system for future use. The best method to overcome this problem is to integrate the PV generator with other power sources such as an electrolyser, hydrogen storage tank, FC system, or battery due to their good features such as high efficiency response, modular production, and fuel flexibility [3, 4]. Its coordination with a PV system could be successful for both grid-connected and stand-alone power applications. Thanks to the rapid response capability of the fuel cell power system, the photovoltaic fuel cell hybrid system can be able to overcome the inconvenience of the intermittent power generation. Furthermore, unlike a secondary
Analysis of Principle and Key Technology of the Hybrid Power Generation System with Wind Turbine, Photovoltaic and Electric Storage  [PDF]
Hongchun Yao,Ming Xu
International Journal of Computer and Electrical Engineering , 2013, DOI: 10.7763/ijcee.2013.v5.699
Abstract: This paper proposes the meaning and essentiality of developing the hybrid power generation system with wind turbine, photovoltaic and electric storage, and expatiates the basic principle of the system. Then, this paper discusses the key technology of Wind-PV-ES ratio optimization algorithm, hybrid power generation system optimization integration, power estimation, integrated monitoring, and maintenance. Finally, the development and application outlook of the system in China is analyses and proved.
10 kW combined hybrid (wind and solar photovoltaic) energy systems for isolated generating system  [PDF]
M. Muralikrishna,V. Lakshminarayana
Journal of Engineering and Applied Sciences , 2011,
Abstract: There is a potentially vast world market for stand-alone power sources. In rural districts of the developing world, the energy consumption per capita is very low and basic energy needs are for water pumping, electricity supplies to small hospitals, lighting, cooling and telecommunications. Often the cost of connection to the grid in remote locations cannot be justified. Photovoltaic and wind power can meet these needs, but either source alone provides an intermittent supply and energy storage is needed to deliver a reliable supply. However, these two sources are complementary since sunny days are usually calm and strong winds are often accompanied by cloud and may occur at night. A combined plant therefore has higher availability than either individual source and so needs less storage capacity. A stand-alone electrical supply system is described which combines the output of wind a solar Photovoltaic generating systems. The experimental system comprise wind and solar collectors, each of 5 KW rating, with a lead-acid battery for storage and a 10 KW PWM inverter for the final output. The wind turbine generator is a 200 rpm, direct drive, Permanent-magnet, axial-flux machine based on the ‘Torus’ configuration. Its three-phase output is rectified to form a variable-voltage dc link. The power converter uses two dc-dc converters connected in series, each with a bypass diode which conducts continuously when the corresponding source is not available. For all load demands the levelised energy cost for PV-wind hybrid system is always lower than that of standalone solar PV or wind system. The PV wind hybrid option is techno-economically viable for rural electrification.
Hybrid Control Strategy for Matrix Converter Fed Wind Energy Conversion System  [PDF]
Jamna Ayadathil, Jamuna Venkatesan
Circuits and Systems (CS) , 2016, DOI: 10.4236/cs.2016.710259
Abstract: In this paper, a hybrid control strategy for a matrix converter fed wind energy conversion system is presented. Since the wind speed may vary, output parameters like power, frequency and voltage may fluctuate. Hence it is necessary to design a system that regulates output parameters, such as voltage and frequency, and thereby provides a constant voltage and frequency output from the wind energy conversion system. Matrix converter is used in the proposed solution as the main power conditioner as a more efficient alternative when compared to traditional back-back converter structure. To control the output voltage, a vector modulation based refined control structure is used. A power tracker is included to maximize the mechanical output power of the turbine. Over current protection and clamp circuit input protection have been introduced to protect the system from over current. It reduces the spikes generated at the output of the converter. The designed system is capable of supplying an output voltage of constant frequency and amplitude within the expected ranges of input during the operation. The matrix converter control using direct modulation method, modified Venturini modulation method and vector modulation method was simulated, the results were compared and it was inferred that vector modulation method was superior to the other two methods. With the proposed technique, voltage transfer ratio and harmonic profile have been improved compared to the other two modulation techniques. The behaviour of the system is corroborated by MATLAB Simulink, and hardware is realized using an FPGA controller. Experimental results are found to be matching with the simulation results.
PMSG Wind Energy Conversion System: Modeling and Control  [PDF]
Omessaad Elbeji, Mouna Ben Hamed, Lassaad Sbita
International Journal of Modern Nonlinear Theory and Application (IJMNTA) , 2014, DOI: 10.4236/ijmnta.2014.33011

In this paper, a model of a variable speed wind turbine using a permanent magnet synchronous generator (PMSG) is presented and the control schemes are proposed. The model presents the aerodynamic part of the wind turbine, the mechanic and the electric parts. Simulations have been conducted with Matlab/Simulink to validate the model and the proposed control schemes.

Frequency control of wind-photovoltaic hybrid power systems

ZHANG Bo-quan,YANG Yi-min,GAN Lu,

控制理论与应用 , 2008,
Abstract: Because of strong randomicity of wind and photovoltaic resources and the variety of loads, the stability of frequency of wind-photovoltaic hybrid power systems becomes low. The optimization of active power not only ensures the safety and stability of frequency of power systems, but also makes it operating economically. However, it is a non-linear optimization problem with constraints and multi-extremum, so this problem is difficult to be solved by traditional methods. With the size of wind-photovoltaic hybrid power farm increasing, the performance of real-time control becomes worse. Based on the above analysis, a mathematical model with the minimal generation cost as objective is constructed. Also a new particle swarm optimization(PSO) based on uniform design and inertia mutation (UMPSO) and a multi-Agent based collaborative optimization method are brought forward, which are used to optimize and control the frequency of power system. Experiment verifies the correctness of the mathematical model and shows the higher effect of UMPSO than that of the standard one. Another experiment indicates that the multi-Agent based collaborative optimization method is preferable for larger power generation farm to the sole population PSO.
Reactive power and voltage control of wind/photovoltaic hybrid power farm based on an improved genetic algorithm

WANG Jian-bin,YANG Yi-min,GAN Lu,

控制理论与应用 , 2008,
Abstract: In the wind/photovoltaic hybrid power generation systems, with strong fluctuation of wind and photovoltaic resources, the stability of voltage becomes low. So voltage control is of the utmost importance for wind/photovoltaic systems. Voltage control is usually implemented by the optimization of local reactive power. The optimization of reactive power is a non-linear combination optimization problem with constraints and multi-extrema. It is very difficult to solve by the traditional methods. So an improved genetic algorithm (IGA) is designed for optimizing reactive power in the wind/photovoltaic hybrid power generation systems. Based on the simple genetic algorithm, the algorithm is improved with the method of coding, operators and termination conditions. Experimental results show that the improved algorithm can remarkably improve the convergent speed and calculational precision, and implement the reactive power and voltage control more efficiently.
Modeling and Simulation of Renewable Hybrid Power System using Matlab Simulink Environment  [PDF]
Cristian Drago? Dumitru,Adrian Gligor
Scientific Bulletin of the ''Petru Maior" University of T?rgu Mure? , 2010,
Abstract: The paper presents the modeling of a solar-wind-hydroelectric hybrid system in Matlab/Simulink environment. The application is useful for analysis and simulation of a real hybrid solar-wind-hydroelectric system connected to a public grid. Application is built on modular architecture to facilitate easy study of each component module influence. Blocks like wind model, solar model, hydroelectric model, energy conversion and load are implemented and the results of simulation are also presented. As an example, one of the most important studies is the behavior of hybrid system which allows employing renewable and variable in time energy sources while providing a continuous supply. Application represents a useful tool in research activity and also in teaching
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