08-03-2011, 01:43 PM
PRESENTED BY
D.SANDEEP KUMAR
[attachment=9773]
ABSTRACT
Human brains always search for the new ways and means which makes life easy and simple. Over the past years great scientists invented great things which changed the world completely and effectively. Even then the thrust for the new inventions was not fulfilled.
So many new things are dumped in to the market time-to-time. Among those electronic gadgets have major share. Now a days our life depends much on electronic devices. All these devices have different cables and pins for their operation. We have to insert those cables in the sockets for the supply and also some times to recharge some of the devices.
Let us take an example as cell phone. We have to charge it time to time other wise it will be switched off. So we use a cable to charge it. If we forget that we will loss some thing. Similarly all the electronic gadgets depend on cables for their operation.
Imagine if all the gadgets take care of themselves and become independent of cables. It will be a great and very useful thing to implement. A professor from MIT named MARIN SOLJACIC had this wonderful thought and with the help of some other members found one interesting concept called WITRICITY. Witricity is a portmanteau for wireless electricity. This concept laid the way to get rid of the wires and cables.
INTRODUCTION
Electricity is today a necessity of modern life. It is difficult to imagine passing a day without electricity. The conventional use of electricity is made possible through the use of wires. However researchers in MIT have devised a means of providing electricity without any wires.
These researchers coined the term WITRICITY, which is basically a portmanteau for wireless electricity. This principle of wireless electricity works on the principle of using coupled resonant objects for the transference of electricity to objects without the use of any wires. A Witricity system consists of a Witricity transmitter and another device called the receiver.
The receiver works on the same principle as radio receivers where the device has to be in the range of the transmitter. It is with the help of resonant magnetic fields that Witricity produces electricity, while reducing the wastage of power. This is unlike the principle adopted by Nikola Tesla in the later part of the 19th century; where conduction based systems were used. The present project on Witricity aims at power transmissions in the range of 100 watts. May be the products using WITRICITY in future might be called Witric or Witric's.
So far the MIT researchers have been able to power a 60 watt light bulb from a power source that is located about seven feet away, while providing forty percent efficiency. This was made possible using two copper coils that were twenty inches in diameter which were designed so that they resonated together in the MHz range. One of these coils were connected to a power source while the other, to a bulb. With this witricity setup, the bulb got powered even when the coils were not in sight.
Resonant induction:
In November 2006, Marin Soljacic and other researchers at the Massachusetts Institute of Technology applied the near field behavior well known in electromagnetic theory to a wireless power transmission concept based on strongly-coupled resonators. In a theoretical analysis (see Ref: Annals of Physics), they demonstrate that, by designing electromagnetic resonators that suffer minimal loss due to radiation and absorption and have a near field with mid-range extent (namely a few times the resonator size), mid-range efficient wireless energy-transfer is possible. The reason is that, if two such resonant objects are brought in mid-range proximity, their near fields (consisting of so-called 'evanescent waves') couple (evanescent wave coupling) and can allow the energy to tunnel/transfer from one object to the other within times much shorter than all loss times, which were designed to be long, and thus with the maximum possible energy-transfer efficiency. Since the resonant wavelength is much larger than the resonators, the field can circumvent extraneous objects in the vicinity and thus this mid-range energy-transfer scheme does not require line-of-sight. By utilizing in particular the magnetic field to achieve the coupling, this method can be safe, since magnetic fields interact weakly with living organisms.
1) Power from mains to antenna, which is made of copper
2) Antenna resonates at a frequency of 6.4MHz, emitting electromagnetic waves
3) 'Tails' of energy from antenna 'tunnel' up to 5m (16.4ft)
4) Electricity picked up by laptop's antenna, which must also be resonating at 6.4MHz. Energy used to re-charge device
5) Energy not transferred to laptop re-absorbed by source antenna. People/other objects not affected as not resonating at 6.4MHz
On June 7, 2007, it was reported that a prototype system had been implemented. In an experimental demonstration (see Ref: Science), the MIT researchers successfully demonstrated the ability to power a 60-watt light bulb wirelessly using two copper coils of 60cm diameter that were 2m (7ft) away at roughly 45% efficiency. The coils were designed to resonate together at 10MHz and were oriented along the same axis. One was connected inductively to a power source, and the other one to a bulb. The setup powered the bulb on, even when the direct line of sight was blocked using a wooden panel.
"Resonant inductive coupling" has key implications in solving the two main problems associated with non-resonant inductive coupling and electromagnetic radiation, one of which is caused by the other; distance and efficiency. Electromagnetic induction works on the principle of a primary coil generating a predominantly magnetic field and a secondary coil being within that field so a current is induced within its coils. This causes the relatively short range due to the amount of power required to produce an electromagnetic field. Over greater distances the non-resonant induction method is inefficient and wastes much of the transmitted energy just to increase range. This is where the resonance comes in and helps efficiency dramatically by "tunneling" the magnetic field to a receiver coil that resonates at the same frequency. Unlike the multiple-layer secondary of a non-resonant transformer, such receiving coils are single layer solenoids with closely spaced capacitor plates on each end, which in combination allow the coil to be tuned to the transmitter frequency thereby eliminating the wide energy wasting "wave problem" and allowing the energy used to focus in on a specific frequency increasing the range.
Beginning in the early 1960s resonant inductive wireless energy transfer was used successfully in implantable medical devices [14] including such devices as pacemakers and artificial hearts. While the early systems used a resonant receiver coil later systems implemented resonant transmitter coils as well. These medical devices are designed for high efficiency using low power electronics while efficiently accommodating some misalignment and dynamic twisting of the coils. The separation between the coils in implantable applications is commonly less than 20 cm. Today resonant inductive energy transfer is regularly used for providing electric power in many commercially available medical implantable devices.
Wireless electric energy transfer for experimentally powering electric automobiles and buses is a higher power application (>10kW) of resonant inductive energy transfer. High power levels are required for rapid recharging and high energy transfer efficiency is required both for operational economy and to avoid negative environmental impact of the system. An experimental electrified roadway test track built circa 1990 achieved 80% energy efficiency
While recharging the battery of a prototype bus at a specially equipped bus stop, the bus could be outfitted with a retractable receiving coil for greater coil clearance when moving.
D.SANDEEP KUMAR
[attachment=9773]
ABSTRACT
Human brains always search for the new ways and means which makes life easy and simple. Over the past years great scientists invented great things which changed the world completely and effectively. Even then the thrust for the new inventions was not fulfilled.
So many new things are dumped in to the market time-to-time. Among those electronic gadgets have major share. Now a days our life depends much on electronic devices. All these devices have different cables and pins for their operation. We have to insert those cables in the sockets for the supply and also some times to recharge some of the devices.
Let us take an example as cell phone. We have to charge it time to time other wise it will be switched off. So we use a cable to charge it. If we forget that we will loss some thing. Similarly all the electronic gadgets depend on cables for their operation.
Imagine if all the gadgets take care of themselves and become independent of cables. It will be a great and very useful thing to implement. A professor from MIT named MARIN SOLJACIC had this wonderful thought and with the help of some other members found one interesting concept called WITRICITY. Witricity is a portmanteau for wireless electricity. This concept laid the way to get rid of the wires and cables.
INTRODUCTION
Electricity is today a necessity of modern life. It is difficult to imagine passing a day without electricity. The conventional use of electricity is made possible through the use of wires. However researchers in MIT have devised a means of providing electricity without any wires.
These researchers coined the term WITRICITY, which is basically a portmanteau for wireless electricity. This principle of wireless electricity works on the principle of using coupled resonant objects for the transference of electricity to objects without the use of any wires. A Witricity system consists of a Witricity transmitter and another device called the receiver.
The receiver works on the same principle as radio receivers where the device has to be in the range of the transmitter. It is with the help of resonant magnetic fields that Witricity produces electricity, while reducing the wastage of power. This is unlike the principle adopted by Nikola Tesla in the later part of the 19th century; where conduction based systems were used. The present project on Witricity aims at power transmissions in the range of 100 watts. May be the products using WITRICITY in future might be called Witric or Witric's.
So far the MIT researchers have been able to power a 60 watt light bulb from a power source that is located about seven feet away, while providing forty percent efficiency. This was made possible using two copper coils that were twenty inches in diameter which were designed so that they resonated together in the MHz range. One of these coils were connected to a power source while the other, to a bulb. With this witricity setup, the bulb got powered even when the coils were not in sight.
Resonant induction:
In November 2006, Marin Soljacic and other researchers at the Massachusetts Institute of Technology applied the near field behavior well known in electromagnetic theory to a wireless power transmission concept based on strongly-coupled resonators. In a theoretical analysis (see Ref: Annals of Physics), they demonstrate that, by designing electromagnetic resonators that suffer minimal loss due to radiation and absorption and have a near field with mid-range extent (namely a few times the resonator size), mid-range efficient wireless energy-transfer is possible. The reason is that, if two such resonant objects are brought in mid-range proximity, their near fields (consisting of so-called 'evanescent waves') couple (evanescent wave coupling) and can allow the energy to tunnel/transfer from one object to the other within times much shorter than all loss times, which were designed to be long, and thus with the maximum possible energy-transfer efficiency. Since the resonant wavelength is much larger than the resonators, the field can circumvent extraneous objects in the vicinity and thus this mid-range energy-transfer scheme does not require line-of-sight. By utilizing in particular the magnetic field to achieve the coupling, this method can be safe, since magnetic fields interact weakly with living organisms.
1) Power from mains to antenna, which is made of copper
2) Antenna resonates at a frequency of 6.4MHz, emitting electromagnetic waves
3) 'Tails' of energy from antenna 'tunnel' up to 5m (16.4ft)
4) Electricity picked up by laptop's antenna, which must also be resonating at 6.4MHz. Energy used to re-charge device
5) Energy not transferred to laptop re-absorbed by source antenna. People/other objects not affected as not resonating at 6.4MHz
On June 7, 2007, it was reported that a prototype system had been implemented. In an experimental demonstration (see Ref: Science), the MIT researchers successfully demonstrated the ability to power a 60-watt light bulb wirelessly using two copper coils of 60cm diameter that were 2m (7ft) away at roughly 45% efficiency. The coils were designed to resonate together at 10MHz and were oriented along the same axis. One was connected inductively to a power source, and the other one to a bulb. The setup powered the bulb on, even when the direct line of sight was blocked using a wooden panel.
"Resonant inductive coupling" has key implications in solving the two main problems associated with non-resonant inductive coupling and electromagnetic radiation, one of which is caused by the other; distance and efficiency. Electromagnetic induction works on the principle of a primary coil generating a predominantly magnetic field and a secondary coil being within that field so a current is induced within its coils. This causes the relatively short range due to the amount of power required to produce an electromagnetic field. Over greater distances the non-resonant induction method is inefficient and wastes much of the transmitted energy just to increase range. This is where the resonance comes in and helps efficiency dramatically by "tunneling" the magnetic field to a receiver coil that resonates at the same frequency. Unlike the multiple-layer secondary of a non-resonant transformer, such receiving coils are single layer solenoids with closely spaced capacitor plates on each end, which in combination allow the coil to be tuned to the transmitter frequency thereby eliminating the wide energy wasting "wave problem" and allowing the energy used to focus in on a specific frequency increasing the range.
Beginning in the early 1960s resonant inductive wireless energy transfer was used successfully in implantable medical devices [14] including such devices as pacemakers and artificial hearts. While the early systems used a resonant receiver coil later systems implemented resonant transmitter coils as well. These medical devices are designed for high efficiency using low power electronics while efficiently accommodating some misalignment and dynamic twisting of the coils. The separation between the coils in implantable applications is commonly less than 20 cm. Today resonant inductive energy transfer is regularly used for providing electric power in many commercially available medical implantable devices.
Wireless electric energy transfer for experimentally powering electric automobiles and buses is a higher power application (>10kW) of resonant inductive energy transfer. High power levels are required for rapid recharging and high energy transfer efficiency is required both for operational economy and to avoid negative environmental impact of the system. An experimental electrified roadway test track built circa 1990 achieved 80% energy efficiency
While recharging the battery of a prototype bus at a specially equipped bus stop, the bus could be outfitted with a retractable receiving coil for greater coil clearance when moving.
