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SOLAR BASED MOBILE CHARGER FOR R URAL AREAS

(Recharge Your Mobile Devices on the Go Using the Energy of the Sun)

With the existing push in the direction of sustainable, clean sources of power, it is no

surprise that solar power has become one of the most popular alternative energy sources. Free

and available everywhere, the power of the sun can be employed to power everything like cel

phones and MP3 player. The sun's energy is usually harvested through solar panels that are made

up of photovoltaic cells. These cells can convert the sun's power into electricity that can be used

for a number of purposes. For private use, a handheld solar hybrid charger can be employed to

recharge little device for instance a MP3 player, a cell phone, or a camera.

A normal PN junction diode is used for unidirectional flow of charge current. The output

of the solar panel depends on the intensity of the solar light. To regulate this voltage, LM317 is

used. LM317 is an adjustable voltage regulator. The regulator circuit is designed to get a fixed

voltage of 5V.

An alternative charger circuit is also provided to charge the mobile by house hold general

purpose 230V in the absence of the sun light. This charge circuit uses regulated 5V, 750mA

power supply. 7805 three terminal voltage regulator is used for voltage regulation. Bridge type

full wave rectifier is used to rectify the ac output of secondary of 230/18V step down

transformer.

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Solar Panel

Unidirectional flowControl Device

Regulator

Batteryunder

charge

Power supply torechargeable battery

Stepdown T/F

BridgeRectifier

FilterCircuit Regulato

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POWER SUPPLY:

The input to the circuit is applied from the regulated power supply. The a.c. input i.e.,

230V from the mains supply is step down by the transformer to 12V and is fed to a rectifier. The

output obtained from the rectifier is a pulsating d.c voltage. So in order to get a pure d.c voltage,

the output voltage from the rectifier is fed to a filter to remove any a.c components present even

after rectification. Now, this voltage is given to a voltage regulator to obtain a pure constant dc

voltage.

Fig: Power supply

Re ulatorFilter

Bridge

Rectifier

Step down

transformer

230V

AC

D.C

Output

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Transformer:

Usually, DC voltages are required to operate various electronic equipment and these

voltages are 5V, 9V or 12V. But these voltages cannot be obtained directly. Thus the a.c input

available at the mains supply i.e., 230V is to be brought down to the required voltage level. This

is done by a transformer. Thus, a step down transformer is employed to decrease the voltage to a

required level.

Rectifier:

The output from the transformer is fed to the rectifier. It converts A.C. into pulsatingD.C. The rectifier may be a half wave or a full wave rectifier. In this project, a bridge rectifier is

used because of its merits like good stability and full wave rectification.

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The Bridge rectifier is a circuit, which converts an ac voltage to dc voltage using both

half cycles of the input ac voltage. The Bridge rectifier circuit is shown in the figure. The circuit

has four diodes connected to form a bridge. The ac input voltage is applied to the diagonally

opposite ends of the bridge. The load resistance is connected between the other two ends of the

bridge.

For the positive half cycle of the input ac voltage, diodes D1 and D3 conduct, whereas

diodes D2 and D4 remain in the OFF state. The conducting diodes will be in series with the load

resistance R L and hence the load current flows through R L.For the negative half cycle of the input

ac voltage, diodes D2 and D4 conduct whereas, D1 and D3 remain OFF. The conducting diodes

D2 and D4 will be in series with the load resistance R L and hence the current flows through R L in

the same direction as in the previous half cycle. Thus a bi-directional wave is converted into a

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unidirectional wave.

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Filter:

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Capacitive filter is used in this project. It removes the ripples from the output of rectifier

and smoothens the D.C. Output received from this filter is constant until the mains voltage and

load is maintained constant. However, if either of the two is varied, D.C. voltage received at this

point changes. Therefore a regulator is applied at the output stage.

Voltage regulator:

As the name itself implies, it regulates the input applied to it. A voltage regulator is an

electrical regulator designed to automatically maintain a constant voltage level. In this project,

power supply of 5V and 12V are required. In order to obtain these voltage levels, 7805 and 7812

voltage regulators are to be used. The first number 78 represents positive supply and the numbers

05, 12 represent the required output voltage levels. The L78xx series of three-terminal

positive regulators is available in TO-220, TO-220FP, TO-3, D2PAK and DPAK

packages and several fixed output voltages, making it useful in a wide rangeof applications. These regulators can provide local on-card regulation,

eliminating the distribution problems associated with single point regulation.

Each type employs internal current limiting, thermal shut-down and safe

area protection, making it essentially indestructible. If adequate heat sinking

is provided, they can deliver over 1 A output current. Although designed

primarily as fixed voltage regulators, these devices can be used with

external components to obtain adjustable voltage and currents.

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Solar Panel

A solar panel (photovoltaic module or photovoltaic panel ) is a packaged

interconnected assembly of solar cells, also known as photovoltaic cells . The solar panel is used

as a component in a larger photovoltaic system to offer electricity for commercial and residential

applications.

Because a single solar panel can only produce a limited amount of power, many

installations contain several panels. This is known as a photovoltaic array . A photovoltaic

installation typically includes an array of solar panels, an inverter , batteries and interconnection

wiring.

Photovoltaic systems are used for either on- or off-grid applications, and for solar panels on

spacecraft .

http://en.wikipedia.org/wiki/Solar_cellshttp://en.wikipedia.org/wiki/Photovoltaic_cellshttp://en.wikipedia.org/wiki/Photovoltaic_arrayhttp://en.wikipedia.org/wiki/Inverter_(electrical)http://en.wikipedia.org/wiki/Battery_(electricity)http://en.wikipedia.org/wiki/Off-gridhttp://en.wikipedia.org/wiki/Solar_panels_on_spacecrafthttp://en.wikipedia.org/wiki/Solar_panels_on_spacecrafthttp://en.wikipedia.org/wiki/Solar_cellshttp://en.wikipedia.org/wiki/Photovoltaic_cellshttp://en.wikipedia.org/wiki/Photovoltaic_arrayhttp://en.wikipedia.org/wiki/Inverter_(electrical)http://en.wikipedia.org/wiki/Battery_(electricity)http://en.wikipedia.org/wiki/Off-gridhttp://en.wikipedia.org/wiki/Solar_panels_on_spacecrafthttp://en.wikipedia.org/wiki/Solar_panels_on_spacecraft

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protected from mechanical damage during manufacture, transport, installation and use (in

particular against hail impact, wind and snow loads). This is especially important for wafer-

based silicon cells which are brittle .

protected from moisture, which corrodes metal contacts and interconnects, (and for thin-

film cells the transparent conductive oxide layer ) thus decreasing performance and lifetime.

Most modules are usually rigid, but there are some flexible modules available, based on thin-film

cells.

Electrical connections are made in series to achieve a desired output voltage and/or in parallel to

provide a desired amount of current source capability.

Diodes are included to avoid overheating of cells in case of partial shading. Since cell heating

reduces the operating efficiency it is desirable to minimize the heating. Very few modules

incorporate any design features to decrease temperature, however installers try to provide good

ventilation behind the module.

New designs of module include concentrator modules in which the light is concentrated by an

array of lenses or mirrors onto an array of small cells. This allows the use of cells with a very

high-cost per unit area (such as gallium arsenide ) in a cost-competitive way.

Depending on construction, the photovoltaic can cover a range of frequencies of light and can

produce electricity from them, but sometimes cannot cover the entire solar spectrum

(specifically, ultraviolet , infrared and low or diffused light ). Hence much of

incident sunlight energy is wasted when used for solar panels, although they can give far higher

efficiencies if illuminated with monochromatic light. Another design concept is to split the light

into different wavelength ranges and direct the beams onto different cells tuned to the

http://en.wikipedia.org/wiki/Hailhttp://en.wikipedia.org/wiki/Brittlehttp://en.wikipedia.org/wiki/Thin-film_cellhttp://en.wikipedia.org/wiki/Thin-film_cellhttp://en.wikipedia.org/w/index.php?title=Transparent_conductive_oxide&action=edit&redlink=1http://en.wikipedia.org/wiki/Layerhttp://en.wikipedia.org/wiki/Series_and_parallel_circuits#Series_circuitshttp://en.wikipedia.org/wiki/Series_and_parallel_circuits#Parallel_circuitshttp://en.wikipedia.org/wiki/Diodehttp://en.wikipedia.org/wiki/Concentratorhttp://en.wikipedia.org/wiki/Lens_(optics)http://en.wikipedia.org/wiki/Gallium_arsenidehttp://en.wikipedia.org/wiki/Frequencyhttp://en.wikipedia.org/wiki/Ultraviolethttp://en.wikipedia.org/wiki/Infraredhttp://en.wikipedia.org/w/index.php?title=Diffuse_light&action=edit&redlink=1http://en.wikipedia.org/wiki/Sunlighthttp://en.wikipedia.org/wiki/Hailhttp://en.wikipedia.org/wiki/Brittlehttp://en.wikipedia.org/wiki/Thin-film_cellhttp://en.wikipedia.org/wiki/Thin-film_cellhttp://en.wikipedia.org/w/index.php?title=Transparent_conductive_oxide&action=edit&redlink=1http://en.wikipedia.org/wiki/Layerhttp://en.wikipedia.org/wiki/Series_and_parallel_circuits#Series_circuitshttp://en.wikipedia.org/wiki/Series_and_parallel_circuits#Parallel_circuitshttp://en.wikipedia.org/wiki/Diodehttp://en.wikipedia.org/wiki/Concentratorhttp://en.wikipedia.org/wiki/Lens_(optics)http://en.wikipedia.org/wiki/Gallium_arsenidehttp://en.wikipedia.org/wiki/Frequencyhttp://en.wikipedia.org/wiki/Ultraviolethttp://en.wikipedia.org/wiki/Infraredhttp://en.wikipedia.org/w/index.php?title=Diffuse_light&action=edit&redlink=1http://en.wikipedia.org/wiki/Sunlight

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appropriate wavelength ranges. This is projected to raise efficiency by 50%. Also, the use

of infrared photovoltaic cells can increase the efficiencies, producing power at night.

Sunlight conversion rates (module efficiencies) can vary from 5-18% in commercial production

(solar panels), that can be lower than cell conversion.

The current market leader in efficient solar energy modules is SunPower , whose solar panels

have a conversion ratio of 19.3%, with Sanyo having the most efficient modules at

20.4%. However, a whole range of other companies ( HoloSun , Gamma Solar , NanoHorizons )

are emerging which are also offering new innovations in photovoltaic modules, with a

conversion ratio of around 18%. These new innovations include power generation on the front

and back sides and increased outputs; however, most of these companies have not yet produced

working systems from their design plans, and are mostly still actively improving the technology.

Crystalline silicon modules

Solar Cell

Most solar module are currently produced from silicon PV cells . These are typically categorized

into either monocrystalline or multicrystalline modules.

Thin-film modules

Third generation solar cells are advanced thin-film cells. They produce high-efficiency

conversion at low cost.

http://en.wikipedia.org/wiki/Infrared_photovoltaic_cellhttp://en.wikipedia.org/w/index.php?title=Sunlight_conversion_rate&action=edit&redlink=1http://en.wikipedia.org/wiki/SunPowerhttp://en.wikipedia.org/w/index.php?title=HoloSun&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Gamma_Solar&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=NanoHorizons&action=edit&redlink=1http://en.wikipedia.org/wiki/Solar_Cellhttp://en.wikipedia.org/wiki/Photovoltaic_cellshttp://en.wikipedia.org/wiki/Monocrystallinehttp://en.wikipedia.org/wiki/Multicrystallinehttp://en.wikipedia.org/wiki/Infrared_photovoltaic_cellhttp://en.wikipedia.org/w/index.php?title=Sunlight_conversion_rate&action=edit&redlink=1http://en.wikipedia.org/wiki/SunPowerhttp://en.wikipedia.org/w/index.php?title=HoloSun&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Gamma_Solar&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=NanoHorizons&action=edit&redlink=1http://en.wikipedia.org/wiki/Solar_Cellhttp://en.wikipedia.org/wiki/Photovoltaic_cellshttp://en.wikipedia.org/wiki/Monocrystallinehttp://en.wikipedia.org/wiki/Multicrystalline

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Rigid thin-film modules

In rigid thin film modules , the cell and the module are manufactured in the same production

line.

The cell is created on a glass substrate or superstrate, and the electrical connections are

created in situ , a so called " monolithic integration ". The substrate or superstrate is laminated with

an encapsulant to a front or back sheet, usually another sheet of glass.

The main cell technologies in this category are CdTe, or a-Si , or a-Si+uc-Si tandem, or CIGS (or

variant). Amorphous silicon has a sunlight conversion rate of 6-12%.

Flexible thin-film modules

Flexible thin film cells and modules are created on the same production line by depositing

the photoactive layer and other necessary layers on a flexible substrate .

If the substrate is an insulator (e.g. polyester or polyimide film) then monolithic integration can

be used.

If it is a conductor then another technique for electrical connection must be used.

The cells are assembled into modules by laminating them to a transparent

colourless fluoropolymer on the front side (typically ETFE or FEP ) and a polymer suitable for

bonding to the final substrate on the other side. The only commercially available (in MW

quantities) flexible module uses amorphous silicon triple junction (from Unisolar ).

http://en.wikipedia.org/wiki/Substrate_(materials_science)http://en.wikipedia.org/wiki/Superstratehttp://en.wikipedia.org/w/index.php?title=Monolithic_integration&action=edit&redlink=1http://en.wikipedia.org/wiki/Laminatedhttp://en.wikipedia.org/w/index.php?title=Encapsulant&action=edit&redlink=1http://en.wikipedia.org/wiki/Sheethttp://en.wikipedia.org/wiki/Cadmium_telluridehttp://en.wikipedia.org/wiki/Amorphous_siliconhttp://en.wikipedia.org/wiki/Micromorphous_siliconhttp://en.wikipedia.org/wiki/Copper_indium_gallium_selenidehttp://en.wikipedia.org/wiki/Photoactive_layerhttp://en.wikipedia.org/wiki/Layerhttp://en.wikipedia.org/wiki/Flexible_substratehttp://en.wikipedia.org/wiki/Insulator_(electrical)http://en.wikipedia.org/wiki/Polyesterhttp://en.wikipedia.org/wiki/Polyimidehttp://en.wikipedia.org/wiki/Die_(integrated_circuit)http://en.wikipedia.org/wiki/Laminatinghttp://en.wikipedia.org/wiki/Fluoropolymerhttp://en.wikipedia.org/wiki/ETFEhttp://en.wikipedia.org/wiki/Fluorinated_ethylene_propylenehttp://en.wikipedia.org/wiki/Amorphous_siliconhttp://en.wikipedia.org/wiki/Multijunction_photovoltaic_cellhttp://en.wikipedia.org/w/index.php?title=Unisolar&action=edit&redlink=1http://en.wikipedia.org/wiki/Substrate_(materials_science)http://en.wikipedia.org/wiki/Superstratehttp://en.wikipedia.org/w/index.php?title=Monolithic_integration&action=edit&redlink=1http://en.wikipedia.org/wiki/Laminatedhttp://en.wikipedia.org/w/index.php?title=Encapsulant&action=edit&redlink=1http://en.wikipedia.org/wiki/Sheethttp://en.wikipedia.org/wiki/Cadmium_telluridehttp://en.wikipedia.org/wiki/Amorphous_siliconhttp://en.wikipedia.org/wiki/Micromorphous_siliconhttp://en.wikipedia.org/wiki/Copper_indium_gallium_selenidehttp://en.wikipedia.org/wiki/Photoactive_layerhttp://en.wikipedia.org/wiki/Layerhttp://en.wikipedia.org/wiki/Flexible_substratehttp://en.wikipedia.org/wiki/Insulator_(electrical)http://en.wikipedia.org/wiki/Polyesterhttp://en.wikipedia.org/wiki/Polyimidehttp://en.wikipedia.org/wiki/Die_(integrated_circuit)http://en.wikipedia.org/wiki/Laminatinghttp://en.wikipedia.org/wiki/Fluoropolymerhttp://en.wikipedia.org/wiki/ETFEhttp://en.wikipedia.org/wiki/Fluorinated_ethylene_propylenehttp://en.wikipedia.org/wiki/Amorphous_siliconhttp://en.wikipedia.org/wiki/Multijunction_photovoltaic_cellhttp://en.wikipedia.org/w/index.php?title=Unisolar&action=edit&redlink=1

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So-called inverted metamorphic (IMM) multijunction solar cells made on compound-

semiconductor technology are just becoming commercialized in July 2008. The University of

Michigan 's solar car that won the North American Solar challenge in July 2008 used IMM thin-

film flexible solar cells.

The requirements for residential and commercial are different in that the residential needs are

simple and can be packaged so that as technology at the solar cell progress, the other base line

equipment such as the battery, inverter and voltage sensing transfer switch still need to be

compacted and unitized for residential use. Commercial use, depending on the size of the service

will be limited in the photovoltaic cell arena, and more complex parabolic reflectors and solar

concentrators are becoming the dominant technology.

The global flexible and thin-film photovoltaic (PV) market, despite caution in the overall PV

industry, is expected to experience a CAGR of over 35% to 2019, surpassing 32GW according to

a major new study by IntertechPira.

Module embedded electronics

Several companies have begun embedding electronics into PV modules. This enables performing

Maximum Power Point Tracking ( MPPT ) for each module individually, and the measurement of

performance data for monitoring and fault detection at module level. Some of these solutions

make use of Power Optimizers , a DC to DC converter technology developed to maximize the

power harvest from solar photovoltaic systems.

http://en.wikipedia.org/w/index.php?title=Inverted_metamorphic&action=edit&redlink=1http://en.wikipedia.org/wiki/Multijunction_solar_cellhttp://en.wikipedia.org/wiki/Compound_semiconductorhttp://en.wikipedia.org/wiki/Compound_semiconductorhttp://en.wikipedia.org/wiki/University_of_Michiganhttp://en.wikipedia.org/wiki/University_of_Michiganhttp://en.wikipedia.org/wiki/Solar_carhttp://en.wikipedia.org/w/index.php?title=North_American_Solar_challenge&action=edit&redlink=1http://en.wikipedia.org/wiki/MPPThttp://en.wikipedia.org/wiki/Power_optimizerhttp://en.wikipedia.org/w/index.php?title=Inverted_metamorphic&action=edit&redlink=1http://en.wikipedia.org/wiki/Multijunction_solar_cellhttp://en.wikipedia.org/wiki/Compound_semiconductorhttp://en.wikipedia.org/wiki/Compound_semiconductorhttp://en.wikipedia.org/wiki/University_of_Michiganhttp://en.wikipedia.org/wiki/University_of_Michiganhttp://en.wikipedia.org/wiki/Solar_carhttp://en.wikipedia.org/w/index.php?title=North_American_Solar_challenge&action=edit&redlink=1http://en.wikipedia.org/wiki/MPPThttp://en.wikipedia.org/wiki/Power_optimizer

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Module performance and lifetime

Module performance is generally rated under Standard Test Conditions (STC) : irradiance of

1,000 W/m , solar spectrum of AM 1.5 and module temperature at 25C.

Electrical characteristics include nominal power (P MAX , measured in W), open circuit

voltage (V OC), short circuit current (ISC, measured in amperes ), maximum power

voltage (V MPP),maximum power current (IMPP) and module efficiency (%).

In kWp, kW is kilowatt and the p means peak as peak performance. The p however does not

show the peak performance, but rather the maximum output according to STC .

Solar panels must withstand heat, cold, rain and hail for many years. Many Crystalline

silicon module manufacturers offer warranties that guarantee electrical production for 10 years at

90% of rated power output and 25 years at 80%

Production

7.5 GW of installations were completed and connected in 2009. IMS Research estimates

that shipments of PV modules were far higher. Shipments exceeded installations due to the

record amount of modules shipped in the final quarter of the year to serve installations completed

in the first quarter of 2010 in booming European markets such as Germany, Italy, France and

Czech Republic

http://en.wikipedia.org/wiki/Irradiancehttp://en.wikipedia.org/wiki/W/m2http://en.wikipedia.org/wiki/Spectrumhttp://en.wikipedia.org/wiki/Airmasshttp://en.wikipedia.org/wiki/Whttp://en.wikipedia.org/wiki/Open_circuit_voltagehttp://en.wikipedia.org/wiki/Open_circuit_voltagehttp://en.wikipedia.org/wiki/Short_circuit_currenthttp://en.wikipedia.org/wiki/Amperehttp://en.wikipedia.org/w/index.php?title=Maximum_power_voltage&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Maximum_power_voltage&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Maximum_power_current&action=edit&redlink=1http://en.wikipedia.org/wiki/Hailhttp://en.wikipedia.org/wiki/Crystalline_siliconhttp://en.wikipedia.org/wiki/Crystalline_siliconhttp://en.wikipedia.org/wiki/GWhttp://en.wikipedia.org/w/index.php?title=IMS_Research&action=edit&redlink=1http://en.wikipedia.org/wiki/Shipmenthttp://en.wikipedia.org/wiki/Irradiancehttp://en.wikipedia.org/wiki/W/m2http://en.wikipedia.org/wiki/Spectrumhttp://en.wikipedia.org/wiki/Airmasshttp://en.wikipedia.org/wiki/Whttp://en.wikipedia.org/wiki/Open_circuit_voltagehttp://en.wikipedia.org/wiki/Open_circuit_voltagehttp://en.wikipedia.org/wiki/Short_circuit_currenthttp://en.wikipedia.org/wiki/Amperehttp://en.wikipedia.org/w/index.php?title=Maximum_power_voltage&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Maximum_power_voltage&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Maximum_power_current&action=edit&redlink=1http://en.wikipedia.org/wiki/Hailhttp://en.wikipedia.org/wiki/Crystalline_siliconhttp://en.wikipedia.org/wiki/Crystalline_siliconhttp://en.wikipedia.org/wiki/GWhttp://en.wikipedia.org/w/index.php?title=IMS_Research&action=edit&redlink=1http://en.wikipedia.org/wiki/Shipment

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Procedure

1. keep the solar panel in sunlight

2. As solar panel gets heated up it charges the mobile connected to the output pin.

3. During night mobile can also be charged by using power supply circuit.

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Advantages:

Highly sensitive

Visual identification with LED

Low cost and reliable circuit

Sensitivity can be adjusted

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CONCLUSION

This project presents a SOLAR BASED MOBILE CHARGER FOR RURAL AREAS

Experimental work has been carried out carefully. The result shows that higher efficiency

is indeed achieved using the dual supply. The proposed method is verified to be highly beneficial

for the purpose for rural areas.

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REFERENCE

www. howstuffworks.com

Magazines:

Electronics for you

Electrikindia

http://www.google.com/http://www.google.com/