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====7."[http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=5618014 Photovoltaics — Control of hybrid battery/ultra-capacitor energy storage for stand-alone photovoltaic system]" ====  
====7."[http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=5618014 Photovoltaics — Control of hybrid battery/ultra-capacitor energy storage for stand-alone photovoltaic system]" ====  
'''By  Xiong Liu ; Div. of Power Eng., Nanyang Technol. Univ., Singapore, Singapore ; Peng Wang ; Poh Chiang Loh ; Feng Gao '''  
'''By  Xiong Liu ; Div. of Power Eng., Nanyang Technol. Univ., Singapore, Singapore ; Peng Wang ; Poh Chiang Loh ; Feng Gao ''' <br />
'''Review''':Battery life is an important criterion in a stand-alone photovoltaic system operation due to intermittent characteristic of solar irradiation and demand. This paper presents a stand-alone photovoltaic system with Ni-MH battery and ultra-capacitor serving as its energy storage elements. A control strategy is proposed in this paper to reduce charging and discharging cycles and avoid deep discharges of battery. The battery converter is controlled in current mode to track a charging/discharging reference current which is given by energy management system, whereas the ultra-capacitor converter is controlled to corporate solar irradiation fluctuations, load spikes and variations to maintain a stable dc-link voltage. Isolated PV system with the proposed control schemes is created using MATLAB SIMULINK. An optimum performance is achieved to serve as both high power and high energy sources due to complementary characteristic of battery and ultra-capacitor.
'''Review''':Battery life is an important criterion in a stand-alone photovoltaic system operation due to intermittent characteristic of solar irradiation and demand. This paper presents a stand-alone photovoltaic system with Ni-MH battery and ultra-capacitor serving as its energy storage elements. A control strategy is proposed in this paper to reduce charging and discharging cycles and avoid deep discharges of battery. The battery converter is controlled in current mode to track a charging/discharging reference current which is given by energy management system, whereas the ultra-capacitor converter is controlled to corporate solar irradiation fluctuations, load spikes and variations to maintain a stable dc-link voltage. Isolated PV system with the proposed control schemes is created using MATLAB SIMULINK. An optimum performance is achieved to serve as both high power and high energy sources due to complementary characteristic of battery and ultra-capacitor.



Revision as of 04:03, 28 January 2014

Smart shade Literature Review

1."Photovoltaics — a path to sustainable futures" By Joshua M Pearce

Review: As both population and energy use per capita increase, modern society is approaching physical limits to its continued fossil fuel consumption. The immediate limits are set by the planet’s ability to adapt to a changing atmospheric chemical composition, not the availability of resources. In order for a future society to be sustainable while operating at or above our current standard of living a shift away from carbon based energy sources must occur. An overview of the current state of active solar (photovoltaic, PV) energy technology is provided here to outline a partial solution for the environmental problems caused by accelerating global energy expenditure. The technical, social, and economic benefits and limitations of PV technologies to provide electricity in both off-grid and on-grid applications is critically analyzed in the context of this shift in energy sources. It is shown that PV electrical production is a technologically feasible, economically viable, environmentally benign, sustainable, and socially equitable solution to society’s future energy requirements.



2."Hybrid Micropower Source for Wireless Sensor Network" By Yanqiu Li, Hongyun Yu, Bo Su, and Yonghong Shang

Review:Wireless sensor networks have become a very significant enabling technology in many applications and the use of environmental energy is a feasible source for low-power wireless sensor networks. The challenges of developing a power supply including generation or conversion, storage, and power management are manifold to extend the lifetime of a wireless sensor network. The objective of this research is to develop an intelligent hybrid power system to realize a self-sustaining wireless sensor node. The photovoltaic and thermoelectric generators are adopted as energy converters. The lithium ion battery and ultracapacitor are used as reservoirs. An intelligent power management system has been developed to control the power distribution. The design data and experimental results show that the hybrid micropower source can extend the lifetime of a sensor network.


3."Photovoltaics — A System Design Approach for Unattended Solar Energy Harvesting Supply " By Kimball, J.W. ; Missouri Univ. of Sci. & Technol., Rolla, MO ; Kuhn, B.T. ; Balog, R.S.

Review:Remote devices, such as sensors and communications devices, require continuously available power. In many applications, conventional approaches are too expensive, too large, or unreliable. For short-term needs, primary batteries may be used. However, they do not scale up well for long-term installations. Instead, energy harvesting methods must be used. Here, a system design approach is introduced that results in a highly reliable, highly available energy harvesting device for remote applications. First, a simulation method that uses climate data and target availability produces Pareto curves for energy storage and generation. This step determines the energy storage requirement in watt-hours and the energy generation requirement in watts. Cost, size, reliability, and longevity requirements are considered to choose particular storage and generation technologies, and then to specify particular components. The overall energy processing system is designed for modularity, fault tolerance, and energy flow control capability. Maximum power point tracking is used to optimize solar panel performance. The result is a highly reliable, highly available power source. Several prototypes have been constructed and tested. Experimental results are shown for one device that uses multicrystalline silicon solar cells and lithium-iron-phosphate batteries to achieve 100% availability. Future designers can use the same approach to design systems for a wide range of power requirements and installation locations.




4."Battery Management System for Solar Energy Applications " By Glavin, M. ; Nat. Univ. of Ireland, Galway ; Hurley, W.G.

Review:Generally in photovoltaic applications the storage battery has the highest life time cost in the system; it has a profound affect on the reliability and performance of the system. Currently the most commonly used storage technology for photovoltaic applications is the lead acid battery. The advantages of the lead acid battery are its low cost and great availability. The problem is that photovoltaic panels are not an ideal source for charging batteries. With the lead acid battery the charging regime may have a significant impact on its service life. The battery management system described in this paper aims to optimize the use of the battery, to prolong the life of the battery, making the overall system more reliable and cost effective. Maximum power point tracking will also be incorporated into the battery management system, to move the solar array operating voltage close to the maximum power point under varying atmospheric conditions, in order to draw the maximum power from the array. This paper will describe different battery technologies that are currently used with photovoltaic systems along with some of the charging techniques that are available




5."Design of a Solar-Harvesting Circuit for Batteryless Embedded Systems " By Brunelli, D. ; Dept. of Electron., Comput. Sci. & Syst. (DEIS), Univ. of Bologna, Bologna, Italy ; Moser, C. ; Thiele, L. ; Benini, L.

Review:The limited battery lifetime of modern embedded systems and mobile devices necessitates frequent battery recharging or replacement. Solar energy and small-size photovoltaic (PV) systems are attractive solutions to increase the autonomy of embedded and personal devices attempting to achieve perpetual operation. We present a battery less solar-harvesting circuit that is tailored to the needs of low-power applications. The harvester performs maximum-power-point tracking of solar energy collection under nonstationary light conditions, with high efficiency and low energy cost exploiting miniaturized PV modules. We characterize the performance of the circuit by means of simulation and extensive testing under various charging and discharging conditions. Much attention has been given to identify the power losses of the different circuit components. Results show that our system can achieve low power consumption with increased efficiency and cheap implementation. We discuss how the scavenger improves upon state-of-the-art technology with a measured power consumption of less than 1 mW. We obtain increments of global efficiency up to 80%, diverging from ideality by less than 10%. Moreover, we analyze the behavior of super capacitors. We find that the voltage across the supercapacitor may be an unreliable indicator for the stored energy under some circumstances, and this should be taken into account when energy management policies are used.


6."A stand-alone photovoltaic supercapacitor battery hybrid energy storage system" By Glavin, M.E. ; Power Electron. Res. Centre, Nat. Univ. of Ireland, Galway ; Chan, P.K.W. ; Armstrong, S. ; Hurley, W.G.

Review:Most of the stand-alone photovoltaic (PV) systems require an energy storage buffer to supply continuous energy to the load when there is inadequate solar irradiation. Typically, Valve Regulated Lead Acid (VRLA) batteries are utilized for this application. However, supplying a large burst of current, such as motor startup, from the battery degrades battery plates, resulting in destruction of the battery. An alterative way of supplying large bursts of current is to combine VRLA batteries and supercapacitors to form a hybrid storage system, where the battery can supply continuous energy and the supercapacitor can supply the instant power to the load. In this paper, the role of the supercapacitor in a PV energy control unit (ECU) is investigated by using Matlab/Simulink models. The ECU monitors and optimizes the power flow from the PV to the battery-supercapacitor hybrid and the load. Three different load conditions are studied, including a peak current load, pulsating current load and a constant current load. The simulation results show that the hybrid storage system can achieve higher specific power than the battery storage system.



7."Photovoltaics — Control of hybrid battery/ultra-capacitor energy storage for stand-alone photovoltaic system"

By Xiong Liu ; Div. of Power Eng., Nanyang Technol. Univ., Singapore, Singapore ; Peng Wang ; Poh Chiang Loh ; Feng Gao
Review:Battery life is an important criterion in a stand-alone photovoltaic system operation due to intermittent characteristic of solar irradiation and demand. This paper presents a stand-alone photovoltaic system with Ni-MH battery and ultra-capacitor serving as its energy storage elements. A control strategy is proposed in this paper to reduce charging and discharging cycles and avoid deep discharges of battery. The battery converter is controlled in current mode to track a charging/discharging reference current which is given by energy management system, whereas the ultra-capacitor converter is controlled to corporate solar irradiation fluctuations, load spikes and variations to maintain a stable dc-link voltage. Isolated PV system with the proposed control schemes is created using MATLAB SIMULINK. An optimum performance is achieved to serve as both high power and high energy sources due to complementary characteristic of battery and ultra-capacitor.


8."Photovoltaics — a path to sustainable futures" By Joshua M Pearce

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9."Photovoltaics — a path to sustainable futures" By Joshua M Pearce

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10."Photovoltaics — a path to sustainable futures" By Joshua M Pearce

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