Wireless Pg Using Sps&R-final

7/29/2019 Wireless Pg Using Sps&R-final

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PRESENTED BY

G.SATYA PRATAP [email protected] [email protected]


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CONTENT :

Introduction

History of Free Space Power Transmission

Wireless energy transferHow Does WPT Work

WPT Today

Solar energy conversion

Solar Energy: A limitless source of energy

Development of a Functional System

Model of the Solar Power SatelliteRectenna

Brief introduction of Schottky Barrier

Diode

Efficiency

Applications of WPTAdvantages of SPS

Conclusion

Regency Institute of Technology


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Introduction

A "world system" for "the transmission of electrical energywithout wires" that depends upon the electrical conductivityof the earth was proposed by Tesla in 1904.

WPT is exactly what the name states, to transfer electricalpower from a source to a device without the aid of wires.

Aswireless technologieswere being developed during theearly 1900s, researchers further investigated these different

wireless transmission methods.

http://g/wiki/Wireless_technologieshttp://g/wiki/Wireless_technologies


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H i s t o r y o f F r e e S p a c e

Power TransmissionA power conversion device from microwave to DC, called a

rectenna,Was invented and used for the microwave-powered helicopter.

Later, the point contact semiconductor diodes were replaced by silicon

Schottky-barrier diodes, which raised the microwave-to-DC conversion

efficiency from 40 % to 84 %.Power was successfully transferred from the transmitting large

parabolic antenna dish to the distant rectenna site over a distance of 1.6

km. The DC output was 30 kW.

The concept of the SPS was First proposed by P. E. Glaser in 1968 to

meet both space-based and earth-based power needs.The SPS will generate electric power of the order of several hundreds to

thousands of megawatts using photovoltaic cells of sizable area, and

will transmit the generated power via a microwave beam to the

receiving rectenna site.



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Wireless energy transfer

Wireless energy transfer or wireless power transmission isthe process that takes place in any system where electricalenergyis transmitted from a power source to an electrical

load, without interconnecting wires. Wireless transmissionis employed in cases where instantaneous or continuousenergy transfer is needed, but interconnecting wires areinconvenient, hazardous, or impossible.

With wireless energy transfer, the efficiency is a morecritical parameter and this creates important differences inthese technologies.

http://g/wiki/Electrical_energyhttp://g/wiki/Electrical_energyhttp://g/wiki/Power_supplyhttp://g/wiki/Electrical_loadhttp://g/wiki/Electrical_loadhttp://g/wiki/Technologyhttp://g/wiki/Technologyhttp://g/wiki/Electrical_loadhttp://g/wiki/Electrical_loadhttp://g/wiki/Power_supplyhttp://g/wiki/Electrical_energyhttp://g/wiki/Electrical_energy


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How Does WPT Work?

Wireless power transfer is a varied andcomplicated process.

The mechanisms of converting from RFenergy to DC c and vise versa are the samefor all WPT systems.

The process of converting DC to RF startswith the power, that will be transmitted isfirst tapped from the main power grid atabout 50Hz AC. The voltage is then reducedto a viable load for rectifying into DC.

Solar power is a truly unlimited energy

supply. A constant transmission of energyfrom the satellites down to earth wouldprove that there would be no need for costlystorage devices to hold excess energy.

However problems occur when trying toimplement a WPT system .egency Institute of Technology


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WPT Today

WPT is becoming a world renowned idea and is in a position to change thesociety in countless ways.

In the U.S., Dr Joseph Hawkins and William Brown are experimenting with afully operational microwave powered helicopter that was publiclydemonstrated in 1995 at a conference for WPT in Japan.

Using magnetic induction to make the conversion, the cyclotron was tested tohave greater than 74% efficiency.

Being concerned about global warming, Japan has created an energy plan thatstates that 30% of the worlds electrical needs will come from space by the year2040. The equipment is not being developed but the plan is to have a series ofsolar powered satellites that would provide 1 GW of power each to the mainpower grid. Another experiment titled ISY-METS is one of the most successfulamong recent years.

This proved to be one of the most important steps toward developing a solidWPT system.

Regency Institute of


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Solar energy conversion

Two methods of converting photons to electricity have been studied,Solar Dynamic (SD) and Photovoltaic (PV).

. PV uses semiconductors (e.g. Silicon or Gallium Arsenide) to directlyconvert sunlight photons into electric potential. Commonly known asSolar cells.

A limitless source of energyThe solar energy that reaches the Earth is about 10,000 times totalhuman energy production today and the energy available in near-Earthspace is limitless.

But in order to supplycontinuous electric power, solar systems on Earthneed much greater area for collection, large scale energy storage for supplyduring the night- time and when it's cloudy, and long-distancetransmission from desert areas to population centers.

http://g/w/index.phphttp://g/wiki/Photovoltaichttp://g/wiki/Semiconductorshttp://g/wiki/Siliconhttp://g/wiki/Gallium(III)_arsenidehttp://g/wiki/Electric_potentialhttp://g/wiki/Solar_cellshttp://g/wiki/Solar_cellshttp://g/wiki/Electric_potentialhttp://g/wiki/Gallium(III)_arsenidehttp://g/wiki/Siliconhttp://g/wiki/Semiconductorshttp://g/wiki/Photovoltaichttp://g/w/index.php


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Development of a Functional System Model of

the Solar Power Satellite

SPS is a strawman model of solar power satellites withmicrowave power output of 10 MW.

The primary objective of SPS research is to show whether SPScould be realized with the present technology and to find outtechnical problems.

SPS has the shape like a triangular prism as shown in Figure 2.

SPS moves on an equatorial LEO at an altitude of 1100km.

The spacetenna directs a microwave power beam to theposition where a pilot signal is transmitted from a ground-based segment of power system, the rectenna. Therefore, thespacetenna has to be a huge phased- array antenna in size witha retro directive beam control capability.

So, microwave circuits are connected to each antenna elementand driven by DC power generated in the huge solar panels. Afrequency of 2.45 GHz is assigned to transmit power to theearth.



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Rectenna It is a special type of antenna that rectifies the incoming microwave radiation

into DC current and hence thename Rectenna.

A rectenna comprises of a mesh of dipoles and diodes for absorbing microwave

energy from a transmitter and converting it into electric power.

A simple rectenna can be constructed from a schottky diode placed between

antenna dipoles as shown in Fig. 1. The diode rectifies the current induced inthe antenna by the microwaves. Rectenna are highly efficient at convertingmicrowave energy to electricity.

In future rectennas will be used to generate large-scale power from microwavebeams delivered from orbiting SPS satellites.



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Brief introduction of Schottky Barrier Diode

A Schottky barrier diode is different from a common P/N silicon diode.

a Schottky barrier diode is formed by connecting a metal with a semiconductor.

A Schottky barrier diode is a majority carrier device, while a common diode is a

minority carrier device. Below is the comparison of power consumptionbetween a common diode and a Schottky barrier diode:

P=0.6*1=0.6W

P=1.1*1=1.1W

Another advantage of the Schottky barrier diode is a very low noise index thatis very important for a communication receiver; its working scope may reach20 GH



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Efficiency

The efficiency of wireless power is the ratio between power that reachesthe receiver and the power supplied to the transmitter.

Generally wirelessly transmitted energy is dispersed as the energy

radiates into the environment or is lost as heat at the transmitter orreceiver.

Generally, wireless energy transfer works best at short range;

Although long distances are possible if the transmitters and receiversare physically large, or

The energy is able to be formed into a tight beam, such as with lasers orlarge microwave dishes.

http://g/wiki/Receiverhttp://g/wiki/Transmitterhttp://g/wiki/Transmitterhttp://g/wiki/Receiver


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Advantages

The SPS concept arose because space has several major advantages overearth for the collection of solar power.

There is no air in space, so the satellites would receive somewhat more

intense sunlight, unaffected by weather. More long-term, if not limiting the satellites to orbiting Earth, the

potential amount of power production is enormous.

This allows systems to avoid the expensive storage facilities (eg, lakesbehind dams) necessary in many earth-based renewable or low impact

power generation systems.



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APPLICATIONS

Wireless power transfer has the ability to change the world with all the differentapplications it has to offer.

The first applications that consumers are most likely to see would be a chargingstation that will range from about one to five meters.

Wireless power transfer charging systems are proven to have efficiencies near

that of conventional charging devices.Once wireless power transfer becomes more advanced, the scale of applicationscan begin to grow.

Once the range reaches around twenty meters, entire homes will be able to becharged by a single transmitter located close to the home.

Once this point emerges, consumers can notice cars converting to completely

electric with the capability of being wireless charged.

Roads will adapt to have wireless chargers spaced so far apart so a car will beable to run endlessly.

Wireless power transfer also has an application in the medical field.



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Conclusion From the above presentation we concluded that through use of wireless

power reception through Rectenna is helpful for power generationthroughout 365 days in a year. With out any shortages it is prefered touse this technique in developing countries like India for powergeneration.

The wireless system would combine electrical power transmissionalong with broadcasting and wireless telecommunications, allowing forthe elimination of many existing high-tension power transmission linesand facilitate the interconnection of electrical generation plants on aglobal scale.



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PRESENTED BY:

G.SATYA PRATAP [email protected] [email protected]


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Wireless Pg Using Sps&R-final