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Wireless power transfer

Inductive charging pad for a smartphone as an example of near-field wireless transfer. When the phone is set on the pad, a coil in the pad creates a magnetic field[1] which induces a current in another coil, in the phone, charging its battery.
Generic block diagram of a wireless power system

Wireless power transfer (WPT; also wireless energy transmission or WET) is the transmission of electrical energy without wires as a physical link. In a wireless power transmission system, an electrically powered transmitter device generates a time-varying electromagnetic field that transmits power across space to a receiver device; the receiver device extracts power from the field and supplies it to an electrical load. The technology of wireless power transmission can eliminate the use of the wires and batteries, thereby increasing the mobility, convenience, and safety of an electronic device for all users.[2] Wireless power transfer is useful to power electrical devices where interconnecting wires are inconvenient, hazardous, or are not possible.

Wireless power techniques mainly fall into two categories: Near and far field.[3] In near field or non-radiative techniques, power is transferred over short distances by magnetic fields using inductive coupling between coils of wire, or by electric fields using capacitive coupling between metal electrodes.[4][5][6][7] Inductive coupling is the most widely used wireless technology; its applications include charging handheld devices like phones and electric toothbrushes, RFID tags, induction cooking, and wirelessly charging or continuous wireless power transfer in implantable medical devices like artificial cardiac pacemakers, or electric vehicles. In far-field or radiative techniques, also called power beaming, power is transferred by beams of electromagnetic radiation, like microwaves[8] or laser beams. These techniques can transport energy longer distances but must be aimed at the receiver. Proposed applications for this type include solar power satellites and wireless powered drone aircraft.[9][10][11]

Wireless power transfer is a generic term for a number of different technologies for transmitting energy by means of electromagnetic fields.[12][13][14] The technologies differ in the distance over which they can transfer power efficiently, whether the transmitter must be aimed (directed) at the receiver, and in the type of electromagnetic energy they use: time varying electric fields, magnetic fields, radio waves, microwaves, infrared or visible light waves.[15]

In general a wireless power system consists of a "transmitter" device connected to a source of power such as a mains power line, which converts the power to a time-varying electromagnetic field, and one or more "receiver" devices which receive the power and convert it back to DC or AC electric current which is used by an electrical load.[12][15] At the transmitter the input power is converted to an oscillating electromagnetic field by some type of "antenna" device. The word "antenna" is used loosely here; it may be a coil of wire which generates a magnetic field, a metal plate which generates an electric field, an antenna which radiates radio waves, or a laser which generates light. A similar antenna or coupling device at the receiver converts the oscillating fields to an electric current. An important parameter that determines the type of waves is the frequency, which determines the wavelength.

Wireless power uses the same fields and waves as wireless communication devices like radio,[16][17] another familiar technology that involves electrical energy transmitted without wires by electromagnetic fields, used in cellphones, radio and television broadcasting, and WiFi. In radio communication the goal is the transmission of information, so the amount of power reaching the receiver is not so important, as long as it is sufficient that the information can be received intelligibly.[13][16][17] In wireless communication technologies only tiny amounts of power reach the receiver. In contrast, with wireless power transfer the amount of energy received is the important thing, so the efficiency (fraction of transmitted energy that is received) is the more significant parameter.[13] For this reason, wireless power technologies are likely to be more limited by distance than wireless communication technologies.

Wireless power transfer may be used to power up wireless information transmitters or receivers. This type of communication is known as wireless powered communication (WPC). When the harvested power is used to supply the power of wireless information transmitters, the network is known as Simultaneous Wireless Information and Power Transfer (SWIPT);[18] whereas when it is used to supply the power of wireless information receivers, it is known as a Wireless Powered Communication Network (WPCN).[19][20][21]

An important issue associated with all wireless power systems is limiting the exposure of people and other living beings to potentially injurious electromagnetic fields.[22][23]

  1. ^ Hoffman, Chris (15 September 2017). "How Does Wireless Charging Work?". How-To Geek. How-To Geek LLC. Retrieved 11 January 2018.
  2. ^ Ibrahim, F.N.; Jamail, N.A.M.; Othman, N.A. (2016). "Development of wireless electricity transmission through resonant coupling". 4th IET Clean Energy and Technology Conference (CEAT 2016). pp. 33 (5 .). doi:10.1049/cp.2016.1290. ISBN 978-1-78561-238-1.
  3. ^ Kracek, Jan; Mazanek, Milos (June 2011). "Wireless Power Transmission for Power Supply: State of Art" (PDF). Radioengineering. 20 (2): 457–463.
  4. ^ Cite error: The named reference ECN2011 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference Trancutaneous Capacitive Wireless Power Transfer was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference Capacitive Elements for Wireless Power Transfer to biomedical implants was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference Capacitive Wireless Power Transfer to biomedical implants was invoked but never defined (see the help page).
  8. ^ Miguel Poveda-García; Jorge Oliva-Sanchez; Ramon Sanchez-Iborra; David Cañete-Rebenaque; Jose Luis Gomez-Tornero (2019). "Dynamic Wireless Power Transfer for Cost-Effective Wireless Sensor Networks using Frequency-Scanned Beaming". IEEE Access. 7: 8081–8094. Bibcode:2019IEEEA...7.8081P. doi:10.1109/ACCESS.2018.2886448.
  9. ^ Bush, Stephen F. (2014). Smart Grid: Communication-Enabled Intelligence for the Electric Power Grid. John Wiley & Sons. p. 118. ISBN 978-1118820230.
  10. ^ "Wireless energy transfer". Encyclopedia of terms. PC Magazine Ziff-Davis. 2014. Retrieved 15 December 2014.
  11. ^ Marks, Paul (22 January 2014). "Wireless charging for electric vehicles hits the road". New Scientist.
  12. ^ a b Shinohara, Naoki (2014). Wireless Power Transfer via Radiowaves. John Wiley & Sons. pp. ix–xiii. ISBN 978-1118862964.
  13. ^ a b c Gopinath, Ashwin (August 2013). "All About Transferring Power Wirelessly" (PDF). Electronics for You E-zine: 52–56. Archived from the original (PDF) on 19 January 2015. Retrieved 16 January 2015.
  14. ^ Lu, X.; Wang, P.; Niyato, D.; Kim, D. I.; Han, Z. (2016). "Wireless Charging Technologies: Fundamentals, Standards, and Network Applications". IEEE Communications Surveys and Tutorials. 18 (2): 1413–1452. arXiv:1509.00940. doi:10.1109/comst.2015.2499783. S2CID 8639012.
  15. ^ a b Sun, Tianjia; Xie, Xiang; Zhihua, Wang (2013). Wireless Power Transfer for Medical Microsystems. Springer Science & Business Media. pp. 5–6. ISBN 978-1461477020.
  16. ^ a b Sazonov, Edward; Neuman, Michael R. (2014). Wearable Sensors: Fundamentals, Implementation and Applications. Elsevier. pp. 253–255. ISBN 978-0124186668.
  17. ^ a b Shinohara (2014). Wireless Power Transfer via Radiowaves. John Wiley & Sons. p. 27. ISBN 9781118862964.
  18. ^ Krikidis, Ioannis; Timotheou, Stelios; Nikolaou, Symeon; Zheng, Gan; Ng, Derrick Wing Kwan; Schober, Robert (2014). "Simultaneous wireless information and power transfer in modern communication systems". IEEE Communications Magazine. 52 (11): 104–110. arXiv:1409.0261. Bibcode:2014arXiv1409.0261K. doi:10.1109/MCOM.2014.6957150. S2CID 3462059.
  19. ^ Bi, Suzhi; Zeng, Yong; Zhang, Rui; Dong in Kim; Han, Zhu (2016). "Wireless powered communication networks: An overview". IEEE Wireless Communications. 23 (2): 10–18. arXiv:1508.06366. doi:10.1109/MWC.2016.7462480. S2CID 3504276.
  20. ^ Lu, Xiao; Wang, Ping; Niyato, Dusit; Dong in Kim; Han, Zhu (2018). "Maximizing Ergodic Throughput in Wireless Powered Communication Networks". arXiv:1807.05543 [cs.IT].
  21. ^ Bi, Suzhi; Ho, Chin Keong; Zhang, Rui (2015). "Wireless powered communication: Opportunities and challenges". IEEE Communications Magazine. 53 (4): 117–125. arXiv:1408.2335. doi:10.1109/MCOM.2015.7081084. S2CID 7127575.
  22. ^ Lu, Yan; Ki, Wing-Hung (2017). CMOS Integrated Circuit Design for Wireless Power Transfer. Springer. pp. 2–3. ISBN 978-9811026157.
  23. ^ Sun, Tianjia; Xie, Xiang; Wang, Zhihua (2013). Wireless Power Transfer for Medical Microsystems. Springer Science and Business Media. ISBN 978-1461477020.

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نقل الطاقة لاسلكيا Arabic Transmissió d'energia sense fil Catalan Bezdrátové nabíjení Czech Drahtlose Energieübertragung German Transmisión inalámbrica de energía Spanish انتقال بی‌سیم برق FA Transmission d'énergie sans fil French वायरलेस उर्जा हस्तांतरण HI Bežični prijenos energije Croatian Daya nirkabel ID

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