13-05-2011, 09:15 AM
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1. INTRODUCTION
Can we imagine the life without electrical wires? From now answer to this question is Yes. The method proposed in the present paper called “WiTricity “will facilitate to Transfer power without using wires. (WiTricity is nothing but wireless electricity. Transmission of electrical energy from one object to another without the use of wires is called as WiTricity. WiTricity will ensure that the cell phones, laptops, iPods and other power hungry devices get charged on their own, eliminating the need of plugging them in. Even better, because of WiTricity some of the devices won't require batteries to operate.)
The efficient midrange power can be transmitted to any device which uses that range of power by the technique used in this WiTricity concept. Now a days there is a Rapid development of autonomous electronics like Laptops, Cell-phones, House-hold robots and all the above devices typically rely on chemical energy storage(Battery) .As they are becoming daily needs to present generation, Wireless energy transfer would be useful for many applications as above and they need midrange energy. This is the main reason to prepare this paper. When two Magnetically Resonating objects at “Strongly coupled” regime tend to exchange energy efficiently by transfer of power in the non-radiating fields. This is the basic principle involved in it. By taking two coils having same magnetic resonance and one is coupled to source and other is coupled to Device. So that the energy transfer is efficient even the air gap between them is high.
This paper describes the basic history of wireless power transmission, what are Magnetic resonance and strongly coupled regime, Experimental design, Range and rate of coupling (coupling calculations) and Design of parameters and Simulation for variation of power with and without the external object between source and load.
The technology used for wireless power transmission is known as WiTricity. Wireless power transmission is not a new idea; Nikola Tesla proposed theories of wireless power transmission in the late 1800s and early 1900s. Tesla's work was impressive, but it did not immediately lead to wide spread practical methods for wireless power transmission. Since then many researchers have developed several techniques for moving electricity over long distances without wires. Some exist only as theories or prototypes, but others are already in use. In 2006 researchers at Massachusetts Institute of Technology led by Marine Soijacic discovered an efficient way to transfer power between coils separated by a few meters. They have dubbed this technology as WiTricity.
WiTricity is based upon coupled resonant objects. Two resonant objects of the same resonant frequency tend to exchange energy efficiently, while not interchanging the surroundings. The researchers demonstrate the ability to transfer 60W with approximately 40% efficiency over distance in excess of 2 meters. Currently the project is looking for power transmission in the range of 100watts. As WiTricity is in the development stage, lots of work is to be done in improving the range of power transmission and efficiency. This chapter provides a literature review of the history of wireless power transfer throughout the last century. All of the methods that have been used to achieve wireless power transfer will be reviewed along with the advantages and disadvantages of each method. The chapter will conclude with a small discussion on issues with wireless power transfer.
2. What’s Happening Today!!!!!
Currently, wired electricity powers nearly everything. It travels through wires in the form of Alternating Current, and powers most of our devices in the form of Direct Current.
In our present electricity generation system we waste more than half of its resources. Especially the transmission and distribution losses are the main concern of the present power technology.
The resistance of the wire used in the electrical grid distribution system causes a loss of 26-30% of the energy generated. This loss implies that our present system of electrical distribution is only 70-74% efficient. We have to think of alternate technology to transmit and distribute the electricity. The transmission of power without wires may be one noble alternative for electricity transmission.
What do you mean by WiTricity!!!
The Transfer of Electricity from one place to another without wires is known as “WiTricity”.
On June 7 ’07, a team of researchers at MIT announced the successful operation of WiTricity concept.
They had lit up a 60W bulb with a power source at a distance of 7 feet(over 2m) with no wires.
Wireless transmission is useful in cases where instantaneous or continuous energy transfer is needed, without connecting wires.
Most common form of wireless power is carried out, using electrodynamic induction, microwaves or lasers
3. The Brain behind WiTricity
Prof. Marin Soljacic from Massachusetts Institute of Technology (MIT), is the one who has proved that magnetic coupled resonance can be utilized in order to transfer energy without wires. What's even more interesting is how he came about this idea. Soljacic, just like any of us was fed up of his 'low battery' beeping cell phone and wondered just like any of us if there was a way to get rid of this 'charging problem'.
However, here is where the difference between Soljacic and any of us comes in. He didn't just stand there wondering, instead he tried to figure out if there existed any physical phenomenon which could be of some help. He remembered Michael Faraday's discovery of electromagnetic induction (1831) and used it to come up with WiTricity
4. WiTricity Basics
There are 3 major types of wireless energy transfer:
Short range; Inductive Coupling
Medium range; Resonant Induction
Long range; Electromagnetic Wave Power Transfer
Short Range Wireless Energy Transmission: Inductive Coupling
What Is Inductive Coupling?
Inductive Coupling is a method for short range wireless energy transfer.
Its range can vary, but it’s often very short.
Because of its short range it usually is used when the device containing the receiver and the device containing the transmitter are touching.
How does Inductive Coupling Work?
Inductive coupling works on the principles of electromagnetism:
When a current (electricity) passes through a wire, it generates a magnetic field perpendicular to the wire.
This effect can be magnified through coiling the wire.
When a wire is in proximity to a magnetic field, it generates a current in that wire.
Transferring energy between wires through magnetic fields is inductive coupling.
Magnetic fields decay quickly , making inductive coupling effective only at very short range
[attachment=13690]
[attachment=13689]
1. INTRODUCTION
Can we imagine the life without electrical wires? From now answer to this question is Yes. The method proposed in the present paper called “WiTricity “will facilitate to Transfer power without using wires. (WiTricity is nothing but wireless electricity. Transmission of electrical energy from one object to another without the use of wires is called as WiTricity. WiTricity will ensure that the cell phones, laptops, iPods and other power hungry devices get charged on their own, eliminating the need of plugging them in. Even better, because of WiTricity some of the devices won't require batteries to operate.)
The efficient midrange power can be transmitted to any device which uses that range of power by the technique used in this WiTricity concept. Now a days there is a Rapid development of autonomous electronics like Laptops, Cell-phones, House-hold robots and all the above devices typically rely on chemical energy storage(Battery) .As they are becoming daily needs to present generation, Wireless energy transfer would be useful for many applications as above and they need midrange energy. This is the main reason to prepare this paper. When two Magnetically Resonating objects at “Strongly coupled” regime tend to exchange energy efficiently by transfer of power in the non-radiating fields. This is the basic principle involved in it. By taking two coils having same magnetic resonance and one is coupled to source and other is coupled to Device. So that the energy transfer is efficient even the air gap between them is high.
This paper describes the basic history of wireless power transmission, what are Magnetic resonance and strongly coupled regime, Experimental design, Range and rate of coupling (coupling calculations) and Design of parameters and Simulation for variation of power with and without the external object between source and load.
The technology used for wireless power transmission is known as WiTricity. Wireless power transmission is not a new idea; Nikola Tesla proposed theories of wireless power transmission in the late 1800s and early 1900s. Tesla's work was impressive, but it did not immediately lead to wide spread practical methods for wireless power transmission. Since then many researchers have developed several techniques for moving electricity over long distances without wires. Some exist only as theories or prototypes, but others are already in use. In 2006 researchers at Massachusetts Institute of Technology led by Marine Soijacic discovered an efficient way to transfer power between coils separated by a few meters. They have dubbed this technology as WiTricity.
WiTricity is based upon coupled resonant objects. Two resonant objects of the same resonant frequency tend to exchange energy efficiently, while not interchanging the surroundings. The researchers demonstrate the ability to transfer 60W with approximately 40% efficiency over distance in excess of 2 meters. Currently the project is looking for power transmission in the range of 100watts. As WiTricity is in the development stage, lots of work is to be done in improving the range of power transmission and efficiency. This chapter provides a literature review of the history of wireless power transfer throughout the last century. All of the methods that have been used to achieve wireless power transfer will be reviewed along with the advantages and disadvantages of each method. The chapter will conclude with a small discussion on issues with wireless power transfer.
2. What’s Happening Today!!!!!
Currently, wired electricity powers nearly everything. It travels through wires in the form of Alternating Current, and powers most of our devices in the form of Direct Current.
In our present electricity generation system we waste more than half of its resources. Especially the transmission and distribution losses are the main concern of the present power technology.
The resistance of the wire used in the electrical grid distribution system causes a loss of 26-30% of the energy generated. This loss implies that our present system of electrical distribution is only 70-74% efficient. We have to think of alternate technology to transmit and distribute the electricity. The transmission of power without wires may be one noble alternative for electricity transmission.
What do you mean by WiTricity!!!
The Transfer of Electricity from one place to another without wires is known as “WiTricity”.
On June 7 ’07, a team of researchers at MIT announced the successful operation of WiTricity concept.
They had lit up a 60W bulb with a power source at a distance of 7 feet(over 2m) with no wires.
Wireless transmission is useful in cases where instantaneous or continuous energy transfer is needed, without connecting wires.
Most common form of wireless power is carried out, using electrodynamic induction, microwaves or lasers
3. The Brain behind WiTricity
Prof. Marin Soljacic from Massachusetts Institute of Technology (MIT), is the one who has proved that magnetic coupled resonance can be utilized in order to transfer energy without wires. What's even more interesting is how he came about this idea. Soljacic, just like any of us was fed up of his 'low battery' beeping cell phone and wondered just like any of us if there was a way to get rid of this 'charging problem'.
However, here is where the difference between Soljacic and any of us comes in. He didn't just stand there wondering, instead he tried to figure out if there existed any physical phenomenon which could be of some help. He remembered Michael Faraday's discovery of electromagnetic induction (1831) and used it to come up with WiTricity
4. WiTricity Basics
There are 3 major types of wireless energy transfer:
Short range; Inductive Coupling
Medium range; Resonant Induction
Long range; Electromagnetic Wave Power Transfer
Short Range Wireless Energy Transmission: Inductive Coupling
What Is Inductive Coupling?
Inductive Coupling is a method for short range wireless energy transfer.
Its range can vary, but it’s often very short.
Because of its short range it usually is used when the device containing the receiver and the device containing the transmitter are touching.
How does Inductive Coupling Work?
Inductive coupling works on the principles of electromagnetism:
When a current (electricity) passes through a wire, it generates a magnetic field perpendicular to the wire.
This effect can be magnified through coiling the wire.
When a wire is in proximity to a magnetic field, it generates a current in that wire.
Transferring energy between wires through magnetic fields is inductive coupling.
Magnetic fields decay quickly , making inductive coupling effective only at very short range
