Wi tricity


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Wi tricity

  1. 1. WiTricityWiTricity
  2. 2. Wireless Power TransmissionWireless Power Transmission 05/27/14 Wireless Power Transmission 2
  3. 3. What is WPT?What is WPT? The transmission of energy from one place to another without using wires Conventional energy transfer is using wires But, the wireless transmission is made possible by using various technologies 05/27/14 Wireless Power Transmission 3
  4. 4. HistoryHistory Nikola Tesla in late 1890s Pioneer of induction techniques His vision for “World Wireless System” The 187 feet tall tower to broadcast energy All people can have access to free energy Due to shortage of funds, tower did not operate 05/27/14 Wireless Power Transmission 4
  5. 5. ORIGINAL WORK OF TESLAORIGINAL WORK OF TESLA 05/27/14 Wireless Power Transmission 5
  6. 6.  There’s something new coming up to play with ‘Wireless Electricity’.  In the first successful trial of its kind, the team was able to illuminate a 60-watt light bulb 7ft away .  The team from Massachusetts Institute of Technology, who call their invention ‘WiTricity‘.
  7. 7. What Is Inductive Coupling? InductiveCoupling is a method for short range wireless energy transfer.  Its range can vary, but it’s often very short. Short Range Wireless EnergyShort Range Wireless Energy Transmission: Inductive CouplingTransmission: Inductive Coupling
  8. 8. Inductive couplingInductive coupling Primary and secondary coils are not connected with wires. Energy transfer is due to Mutual Induction 05/27/14 Wireless Power Transmission 8
  9. 9. How does Inductive CouplingHow does Inductive Coupling Work?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. When a wire is in proximity to a magnetic field, it generates a current in that wire. Magnetic fields decay quickly , making inductive coupling effective only at very short ranges.
  10. 10.  What Is Resonant Induction?  A group of engineers at MIT came up with the idea to use resonant induction to transmit power wirelessly. They deemed their result “WiTricity” (like Wi-Fi) . WiTricity can transmit electricity wirelessly at 40% efficiency to about 7 feet. Medium Range Wireless EnergyMedium Range Wireless Energy Transmission: Resonant InductionTransmission: Resonant Induction
  11. 11. Resonance Inductive Coupling(RIC)Resonance Inductive Coupling(RIC) Combination of inductive coupling and resonance Resonance makes two objects interact very strongly Inductance induces current 05/27/14 Wireless Power Transmission 11
  12. 12. How resonance in RIC?How resonance in RIC? Coil provides the inductance Capacitor is connected parallel to the coil Energy will be shifting back and forth between magnetic field surrounding the coil and electric field around the capacitor Radiation loss will be negligible 05/27/14 Wireless Power Transmission 12
  13. 13. Block diagram of RICBlock diagram of RIC 05/27/14 Wireless Power Transmission 13
  14. 14. An exampleAn example 05/27/14 Wireless Power Transmission 14
  15. 15. WiTricity (contd…)WiTricity (contd…) 05/27/14 Wireless Power Transmission 16
  16. 16. DisadvantagesDisadvantages Distance constraint Field strengths have to be under safety levels Initial cost is high In RIC, tuning is difficult High frequency signals must be the supply Air ionization technique is not feasible 05/27/14 Wireless Power Transmission 17
  17. 17. Microwave PowerMicrowave Power Transfer(MPT)Transfer(MPT) Transfers high power from one place to another. Two places being in line of sight usually Steps: ◦ Electrical energy to microwave energy ◦ Capturing microwaves using rectenna ◦ Microwave energy to electrical energy 05/27/14 Wireless Power Transmission 18
  18. 18. MP T (contd…)MP T (contd…) AC can not be directly converted to microwave energy AC is converted to DC first DC is converted to microwaves using magnetron Transmitted waves are received at rectenna which rectifies, gives DC as the output DC is converted back to AC 05/27/14 Wireless Power Transmission 19
  19. 19. Solar Power Satellites (SPS)Solar Power Satellites (SPS) To provide energy to earth’s increasing energy need To efficiently make use of renewable energy i.e., solar energy SPS are placed in geostationary orbits 05/27/14 Wireless Power Transmission 20
  20. 20. SPS (contd…)SPS (contd…) Solar energy is captured using photocells Each SPS may have 400 million photocells Transmitted to earth in the form of microwaves/LASER Using rectenna/photovoltaic cell, the energy is converted to electrical energy Efficiency exceeds 95% if microwave is used. 05/27/14 Wireless Power Transmission 21
  21. 21. RectennaRectenna Stands for rectifying antenna Consists of mesh of dipoles and diodes Converts microwave to its DC equivalent Usually multi-element phased array 05/27/14 Wireless Power Transmission 22
  22. 22. Rectenna in USRectenna in US Rectenna in US receives 5000MW of power from SPS It is about one and a half mile long 05/27/14 Wireless Power Transmission 23
  23. 23. Other projectsOther projects Alaska’21 Grand Bassin Hawaii 05/27/14 Wireless Power Transmission 24
  24. 24. MIT's WiTricity is only 40 to 45% efficient and they have to be twice as efficient to compete with the traditional chemical batteries.  Aim is to get a robotic vacuum or a laptop working, charging devices placed anywhere in the room  The researchers have said that in another five years time, they will come up with a WiTricity system for commercial use. What's the Future of WiTricity?What's the Future of WiTricity?
  25. 25. ConclusionConclusion Transmission without wires- a reality Efficient Low maintenance cost. But, high initial cost Better than conventional wired transfer Energy crisis can be decreased Low loss In near future, world will be completely wireless 05/27/14 Wireless Power Transmission 26