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Inductive charging

From Wikipedia, the free encyclopedia
"Wireless charging" redirects here. For other power transfer, see conductive wireless charging.
The primary coil in the charger induces a current in the secondary coil in the device being charged.

Inductive charging, also known as wireless charging or cordless charging, is a type of wireless power transfer. It uses electromagnetic induction to provide electricity to portable devices. Inductive charging is also used in vehicles, power tools, electric toothbrushes, and medical devices. The equipment can be placed over an inductive pad free of any electrical contacts such as a dock or plug.

Inductive charging transfers energy through inductive coupling: alternating current passes through an induction coil, generating a fluctuating magnetic field, which creates an induced alternating electric current in a nearby secondary coil. The alternating current can be rectified to a direct current which charges a battery or provides operating power.[1][2]

Greater distances between sender and receiver coils, such as those required for wirelessly charging electric vehicles, can be achieved with resonant inductive coupling. The alternating current of the system can use a resonance frequency tuned with capacitors to create a transmitter and receiver LC circuit with a specific resonance frequency. The frequency is chosen depending on the distance desired for optimal efficiency.[1] Charging efficiency is sensitive to lateral, longitudinal, and vertical misalignment.[3] Some resonant inductive coil systems align their coils by having the receiver coils mounted on a movable arm that can be lowered closer to the transmitter coils, for example it can be lowered from the underside of a truck closer to a transmitter coil on the ground.[4]

Applications

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Applications of inductive charging can be divided broadly into low power and high power. Low power applications generally target consumer electronic devices such as cell phones, handheld devices, computers, and similar devices which normally require power below 100 watts. The AC utility frequency of 50 or 60 hertz is often used,[5] or in the case of Qi-compliant devices, frequencies in the range of 87 to 205 kHz are typical.[6] High power inductive charging generally refers to power above 1 kilowatt. Such power is required for electric vehicles, and some implementations reach 300 kilowatts or higher. High-power inductive charging systems use resonant inductive coupling for higher efficiency. These systems are usually implemented in the long wave range of frequencies up to 130 kHz. The use of short wave frequencies can enhance the system's efficiency and size but would eventually transmit the signal worldwide.[7] High power at 85 kHz raise the concern of electromagnetic compatibility and radio frequency interference over background noise levels at ranges of up to 300 km (190 mi).[8]

Inductive charging offers protected connections free of need of corrosion protection. Induction circuits offer protection from faults such as short circuits due to insulation failure, especially where connections are made or broken frequently.[9] Without the need to constantly plug and unplug the device, there is significantly less wear and tear on the socket of the device and the attaching cable.[9] For embedded medical devices, the transmission of power via a magnetic field passing through the skin avoids the infection risks associated with wires penetrating the skin.[10] Automatic operation of inductive charging in roads can allows vehicles to operate without charging stops through opportunity charging over inductive coils embedded in the road.[11]

Power losses and waste heat

[edit]
Charging with induction (left image) creates more waste heat than using a cable (right image).

Due to the lower efficiency of inductive charging compared to conductive charging, devices took 15 percent longer to charge when supplied power is the same amount when tested in 2018.[12] Inductive charging also requires drive electronics and coils in both device and charger, increasing the complexity and cost of manufacturing.[13][14] Mobility is more limited with inductive charging compared to charging with a cable, as the mobile device must be left on a pad to charge, and cannot be moved around or easily operated while charging. With some standards, charging can be maintained at a distance, but only with nothing present between the transmitter and receiver.[9]

Inefficiency has other costs besides longer charge times. Inductive chargers produce more waste heat than wired chargers, which may negatively impact battery longevity.[15][better source needed] An amateur 2020 analysis of energy use conducted with a Pixel 4 found that a wired charge from 0 to 100 percent consumed 14.26 Wh (watt-hours), while a wireless charging stand used 19.8 Wh, an increase of 39%. Using a generic wireless charging pad and mis-aligning the phone produced consumption up to 25.62 Wh, or an 80% increase. The analysis noted that while this is not likely to be noticeable to individuals, it has negative implications for greater adoption of smartphone wireless charging.[16]

Waste heat is a concern for high-power implementations of inductive charging for transportation. Trials in France in 2023 found risk of thermal damage to the road under regular operating conditions due to the induction coils exceeding temperatures of 100 °C (212 °F).[17]

Standards

[edit]
Wireless charging pad used to charge devices with the Qi standard
Electric vehicle wireless charging station

Electronics

[edit]

The most commercially-successful standard for compatibility between inductive chargers and small electronic devices is the Qi standard, which started development in 2008 and was first published in 2010. It quickly expanded in the mid 2010s[18] and became ubiquitous by the mid 2020s.[19] Other standards include: Power Matters Alliance (PMA), which was publicly announced in January 2012;[20] and Rezence, which was developed by the Alliance for Wireless Power (A4WP) and merged with PMA in 2015 under the AirFuel name.[21]

Electric vehicles

[edit]

A group was launched in May 2010 by the Consumer Electronics Association to set a baseline for interoperability for chargers. General Motors, Toyota, and Ford expressed interest in the technology and the standards effort.[22] Daimler's Head of Future Mobility, Professor Herbert Kohler, expressed caution and said in 2011 that the inductive charging for EVs was at least 15 years away, and the safety aspects of inductive charging for EVs have yet to be looked into in greater detail.[23]

The first standard for vehicle wireless charging was the SAE J2954 standard. It allows inductive car charging over a pad, with power delivery up to 11 kW. The standard provides a methodology for activating the charger only when sufficient alignment is detected.[24] As of 2024, standards for higher-power wireless charging and for charging while driving are being developed.[25] Magne Charge, a largely obsolete inductive charging system, also known as J1773, used to charge battery electric vehicles (BEV) formerly made by General Motors.

DWPT EV standards

[edit]
See also: Electric road § Wireless electric roads

In the 2020s, organizations continued developing dynamic wireless power transfer (DWPT) electric vehicle (EV) charging technologies and standards. Among them: Vedecom,[26] ENRX (formerly IPT),[27] Magment,[28] Electreon, Utah State University, Purdue University, and the University of Auckland.[29] WiPowerOne (an offshoot of the KAIST OLEV project) and Electreon, two wireless electric road companies, have been working on new dynamic inductive charging standards in the early 2020s.[30] IPT (which later became a subsidiary of ENRX[31]) has been working on its PRIMOVE system that uses inductive cables instead of coils, as according to their CEO the existing standards which use coils are "extremely expensive" for dynamic charging.[32] SAE International has started developing standards for dynamic wireless power transfer in 2023.[25] The Michigan Department of Transportation (MDOT) has tested one wireless electric road technology from 2023 to 2025 on a quarter-mile stretch of public road. One of the project's goals is developing an interoperable system that will interact with the infrastructure regardless of manufacturer.[33]

Electronic devices

[edit]
Samsung Galaxy Z smartphones inductively charging smart watches.

Manufacturers of smartphones have started adding inductive charging technology into their devices in the late 2010s, the majority adopting the Qi wireless charging standard.[34] Some battery-powered devices offer wireless bidirectional charging, allowing a charged device to charge the battery of another device.[35][36][37]

Early modern proprietary implementations

[edit]
See also: Wireless power transfer § Inductive coupling
  • Electric toothbrushes which use inductive charging have been commercially available since as early as the 1970s.[38]
  • Visteon introduced in 2007 a device inductive charging system to allow vehicles to charge specially made cell phones and MP3 players with compatible receivers.[39]
  • Energizer introduced in 2009 an inductive charging station for the Wii remote.[40]
  • The 2009 Palm Pre smartphone had an optional inductive charger accessory, the "Touchstone". Further Palm and HP devices used Touchstone charging technology.[41][42]
  • An MIT inductive power project started in 2006, WiTricity, uses a curved coil and capacitive plates.[43][44]

Transportation

[edit]
A wirelessly powered model lorry at the Grand Maket Rossiya museum

Electric vehicle wireless power transfer or wireless charging is generally divided into three categories: stationary charging when the vehicle is parked for an extended period of time; dynamic charging when the vehicle is driven on roads or highways; and quasi-dynamic or semi-dynamic charging, when the vehicle moves at low speeds between stops,[45]: 847  for example when a taxi slowly drives at a taxi rank.[46]

Inductive charging is not considered a mature dynamic charging technology as it delivers the least power of the three electric road technologies, its receivers lose 20%-25% of the supplied power when installed on trucks, and its health effects have yet to be documented, according to a French government working group on electric roads.[47] SAE International notes that wireless charging systems do not have well-established foreign object detection technologies, and proposes establishing safety tests for these technologies. Foreign objects pose a fire or burn risk if metals or organisms are between the ground pad and the receiver when the system is active.[25]

Early developments

[edit]

M. Hutin and M. Le-Blanc proposed in 1894 an apparatus and method to power an electric vehicle with inductive power transfre.[48] At the time, combustion engines proved more popular, and this technology was not widely implemented.[2] In 1972, Professor Don Otto of the University of Auckland proposed a vehicle powered by induction using transmitters in the road and a receiver on the vehicle.[2] Bolger, Kirsten, and Ng implemented in 1978 an electric vehicle powered by inductive power transfer at a frequency of 180 Hz and power of 20 kW.[2] An inductive-charging bus was operated in the 1980s in California, and similar developments in inductive power transfer were being explored in France, Germany, and other European countries.[2]

Early modern examples

[edit]
200kW Charging-Pad for Buses, 2020 Bombardier Transportation.
  • In 1997 Conductix Wampler started with wireless charging in Germany, In 2002 20 buses started in operation In Turin with 60 kW charging. In 2013 the IPT technology was bought by Proov. In 2008 the technology was already used in the house of the future in Berlin with Mercedes A Class. Later Evatran also began development of Plugless Power, an inductive charging system it claims is the world's first hands-free, plugless, proximity charging system for Electric Vehicles.[49] With the participation of the local municipality and several businesses, field trials were begun in March 2010. The first system was sold to Google in 2011 for employee use at the Mountain View campus.[50]
  • Magne Charge inductive charging was employed by several types of electric vehicles around 1998, but was discontinued[51] after the California Air Resources Board selected the SAE J1772-2001, or "Avcon", conductive charging interface[52] for electric vehicles in California in June 2001.[53] General Motors and Toyota agreed on this interface and it was also used in the Chevrolet S-10 EV and Toyota RAV4 EV vehicles.
  • EPCOT Universe of Energy is equipped with moving theater "pews," which take passengers/viewers through the exhibit. They are self-propelled, and inductively recharged when at rest.[54] This exhibit with the recharging technology was in place ca. 2003.
  • In November 2011, the Mayor of London, Boris Johnson, and Qualcomm announced a trial of 13 wireless charging points and 50 EVs in the Shoreditch area of London's Tech City, due to be rolled out in early 2012.[55][56] In October 2014, the University of Utah in Salt Lake City, Utah added an electric bus to its mass transit fleet that uses an induction plate at the end of its route to recharge.[57] UTA, the regional public transportation agency, planned to introduce similar buses in 2018.[58] In November 2012 wireless charging was introduced with 3 buses in Utrecht, The Netherlands. January 2015, eight electric buses were introduced to Milton Keynes, England, which uses inductive charging in the road with IPT technology at either end of the journey to prolong overnight charges.[59]
  • Bombardier-Transportation presented in September 2015 its PRIMOVE 3.6 kW Charger for cars,[60] which was developed at Site in Mannheim, Germany.[61] Primove was bought in 2021 by IPT,[62] which by 2023 became a subsidiary of ENRX.[31]
  • Transport for London trialed inductive charging for double-decker buses in London in 2014.[63]
  • Evatran began selling the Plugless L2 Wireless charging system to the public in 2014.[64]
  • Wärtsilä operated a full-scale pilot installation in 2017 employing 1.6MW of power over 50 cm (20 in) distance between landside and onboard coils for charging of an electric hybrid ferry in commercial operation. The pilot test was run for one year.[65]
  • A partnership between Cabonline, Jaguar, Momentum Dynamics, and Fortum Recharge is trialed wireless charging a taxi fleet in Oslo, Norway. The fleet consisted of 25 Jaguar I-Pace SUVs equipped with inductive charging pads rated at 50-75 kW. The pads use resonant inductive coupling operating at 85 Hz.[66] Momentum Dynamics, which was renamed InductEV, has been undergoing insolvency assignment in 2025.[67]

Dynamic charging

[edit]

Wireless charging of an electric vehicle while driving is known as "dynamic wireless charging" or "dynamic wireless power transfer", DWPT. The first working full-scale DWPT prototype is generally regarded to have been developed at the University of California, Berkeley in the 1980s and 1990s. The first commercialized DWPT system, Online Electric Vehicle (OLEV), was developed as early as 2009 by researchers at the Korea Advanced Institute of Science and Technology (KAIST).[45]: 848  Vehicles using the system draw power from a power source underneath the road surface, which is an array of inductive rails or coils.[68][69] Commercialization efforts of the technology have not been successful because of high costs.[70]

The main technical challenge of DWPT is low efficiency.[71]: 57  The cost of a single wireless electric lane at 50% coverage at large-scale deployment was estimated in 2021 to be about 6.5 million dollars per mile.[72]

The German Ministry of Economy, BMWK tested in-road wireless EV charging infrastructure implemented by Electreon in 2023. The tests included a bus equipped with inductive coils that receive power from a 200-meter strip of transmitters under the road surface. The receivers were able to collect 64.3% of the energy emitted from the transmitters. Installation proved complex and costly, and finding suitable locations for the coils' roadside power cabinets proved difficult.[73]

Effects on road surface

[edit]

Inductive charging infrastructure was found in 2017 to increase the occurrence of reflective cracks in road surfaces.[71]: 64 [74] Testing of various bonding materials between the inductive coils and the asphalt in 2023 showed that standard installation techniques of inductive coils under the asphalt were not satisfactory and resulted in critical strains. Performance was satisfactory with the use of specific bonding resins, with non-critical degradation in performance compared to reference pavements with no inductive coils. Despite satisfactory results, even the best-performing methods showed risk of debonding.[75][76] The 2023 trials showed increased risk of thermal damage to the road under regular operating conditions due to the induction coils exceeding temperatures of 100 °C (212 °F).[17] INDOT has been testing in 2024 a DWPT installation with special polymer-concrete previously used for bridges.[27]: 38m19s 

Medical implications

[edit]

Wireless charging is making an impact in the medical sector by means of being able to charge implants and sensors long-term that is located beneath the skin. Multiple companies offer rechargeable medical implant (e.g. implantable neurostimulators) which use inductive charging. Researchers have been able to print wireless power transmitting antenna on flexible materials that could be placed under the skin of patients. This could mean that under skin devices that could monitor the patient status could have a longer-term life and provide long observation or monitoring periods that could lead to better diagnosis from doctors. These devices may also make charging devices like pacemakers easier on the patient rather than having an exposed portion of the device pushing through the skin to allow corded charging. This technology would allow a completely implanted device making it safer for the patient. It is unclear if this technology will be approved for use – more research is needed on the safety of these devices. While these flexible polymers are safer than ridged sets of diodes they can be more susceptible to tearing during either placement or removal due to the fragile nature of the antenna that is printed on the plastic material. While these medical based applications seem very specific the high-speed power transfer that is achieved with these flexible antennas is being looked at for larger broader applications.[77]

See also

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References

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  1. ^ a b Wireless charging: The state of disunion
  2. ^ a b c d e Treffers, Menno (2015). "History, Current Status and Future of the Wireless Power Consortium and the Qi Interface Specification". IEEE Circuits and Systems Magazine. Vol. 15, no. 2. pp. 28–31. doi:10.1109/mcas.2015.2418973.
  3. ^ Emma Piedel; et al. (May 29, 2024), "Review and Evaluation of Automated Charging Technologies for Heavy-Duty Vehicles", World Electric Vehicle Journal, 15 (6): 235, doi:10.3390/wevj15060235
  4. ^ Insider's Guide to Energy podcast (December 23, 2024), "37 - The Future of Wireless EV Charging: Insights from Electreon's Charlie Levine", YouTube, 3 minutes and 14 seconds
  5. ^ Dipert, Brian (28 March 2019). "Wireless charging: The state of disunion". Retrieved 12 September 2021.
  6. ^ "Qi Specification Introduction". Wireless Power Consortium. p. 11. Archived from the original on November 5, 2019. Retrieved 8 September 2023.
  7. ^ Regensburger, Brandan; Kumar, Ashish; Sreyam, Sinhar; Khurram, Afridi (2018), "High-Performance 13.56-MHz Large Air-Gap Capacitive Wireless Power Transfer System for Electric Vehicle Charging", 2018 IEEE 19th Workshop on Control and Modeling for Power Electronics (COMPEL), IEEE, pp. 1–4, doi:10.1109/COMPEL.2018.8460153, ISBN 978-1-5386-5541-2, S2CID 52285213
  8. ^ Karina Fors (December 2019), "Interference Risks from Wireless Power Transfer for Electric Vehicles" (PDF), Totalförsvarets forskningsinstitut
  9. ^ a b c Madzharov, Nikolay D.; Nemkov, Valentin S. (January 2017). "Technological inductive power transfer systems". Journal of Electrical Engineering. 68 (3). The Journal of Slovak University of Technology: 235–244. Bibcode:2017JEE....68..235M. doi:10.1515/jee-2017-0035.
  10. ^ “Wireless Power For Medical Devices.” MDDI Online, 7 Aug. 2017, www.mddionline.com/wireless-power-medical-devices.
  11. ^ Condliffe, Jamie. "Do you really need wireless charging roads?". MIT Technology Review. Retrieved 2018-10-04.
  12. ^ Chen, Brian X. (3 October 2018). "Wireless Charging Is Here. So What Is It Good For?". The New York Times. Retrieved 2018-10-04.
  13. ^ "How can an electric toothbrush recharge its batteries when there are no metal contacts between the toothbrush and the base?". HowStuffWorks. Blucora. April 2000. Archived from the original on August 17, 2007. Retrieved August 23, 2007.
  14. ^ US 6972543  "Series resonant inductive charging circuit"
  15. ^ Bradshaw, Tim. "Review: the joys of smartphone wireless chargers". Financial Times. Archived from the original on September 19, 2019.
  16. ^ Ravenscraft, Eric (August 5, 2020). "Wireless Charging Is a Disaster Waiting to Happen". onezero. Medium. Retrieved 2020-08-27.
  17. ^ a b Hornych, Pierre (2023), "Design of a pavement solution for electric vehicle charging by induction", XXVIIe Congrès mondial de la Route, AIPCR
  18. ^ S.Y. Ron Hui (2016), "Past, Present and Future Trends of Non-Radiative Wireless Power Transfer" (PDF), CPSS Transactions on Power Electronics and Applications
  19. ^ Simon Hill (August 21, 2025), "What Is Qi2? The Wireless Charging Standard Goes Magnetic", WIRED
  20. ^ "Global Industry Leaders Aim To Refine Power in 21st Century as Smart and Wireless with Formation of the Power Matters Alliance". IEEE newsroom. 2012-01-09. Archived from the original on 2013-07-13.
  21. ^ "Former wireless charging rivals join forces as new AirFuel Alliance". airfuel.org. 2015-11-03. Archived from the original on 2019-06-08. Retrieved 2019-06-08.
  22. ^ Merritt, Rick (October 20, 2010). "Car makers signal interest in wireless charging". EE Times. Archived from the original on October 28, 2010.
  23. ^ Davis, Matt (July 2011). "Mission Critical". Electric & Hybrid, Vehicle Technology International: 68.
  24. ^ "Wireless Power Transfer for Light-Duty Plug-in/Electric Vehicles and Alignment Methodology". SAE International. 23 April 2019.
  25. ^ a b c Katrina Sutton (December 2024), "Effectiveness of Wireless Charging for Electric Transit Buses" (PDF), FTA Reports and Publications, US Department of Transportation Federal Transit Administration, pp. 10–13
  26. ^ "Inductive charging for electric vehicles while driving: a major ecological challenge", vedecom.fr, April 19, 2022
  27. ^ a b Greg Reilly (November 21, 2024), "Dynamic Wireless Power Transfer Pilot Projects", Fall 2024 Kent Seminar Series
  28. ^ Amy M. Dean (August 29, 2021), "German Co. Works Alongside INDOT to Create Concrete Roads that Can Charge EVs as they Drive Along", International Society for Concrete Pavements
  29. ^ "ASPIRE Steering Committee Mtg, Utah Intelligent Electrified Transportation Planning Initiative" (PDF), Utah Department of Transportation, April 8, 2024
  30. ^ Electric Road Systems - PIARC Online Discussion - 17 February 2021, 23 February 2021, 2 hours and 17 minutes into the video
  31. ^ a b ENRX (Mar 27, 2023), ENRX: A new powerhouse in advanced induction technology
  32. ^ E-Mobility Engineering staff (September 6, 2021), Wireless Charging
  33. ^ Robert L. Reid (February 5, 2025), "Looking for anxiety-free EV driving? In-road charging holds promise", ASCE
  34. ^ Alleven, M (2017). "Apple buoys wireless charging industry with WPC membership". FierceWirelessTech. ProQuest 1880513128.
  35. ^ "Which Electric Cars Have Bidirectional Charging (V2L, V2G, V2H)?". Zecar. 21 March 2025.
  36. ^ Younker, Scott (20 February 2025). "iPhone 17 Pro rumor says Apple will finally steal this feature from Samsung Galaxy phones". Tom's Guide.
  37. ^ Pocket-lint (2021-07-30). "What is reverse wireless charging?". www.pocket-lint.com. Retrieved 2022-04-21.
  38. ^ David L. Heiserman (1974), Handbook of Small Appliance Troubleshooting and Repair, Prentice-Hall, p. 182, ISBN 9780133817492
  39. ^ "Visteon to unveil wireless charger for your car at CES". mobilemag.com. 2007-01-03. Archived from the original on 2013-06-06.
  40. ^ "Energizer Induction Charger for Wii Preview". IGN.com. 2009-04-28. Archived from the original on 2009-05-02.
  41. ^ Miller, Paul (2009-01-08). "Palm Pre's wireless charger, the Touchstone". Engadget. Archived from the original on 2017-09-12.
  42. ^ Mokey, Nick (February 25, 2010). "Palm Pre Plus Review". Digital Trends. Archived from the original on March 24, 2010. Retrieved 2010-03-09.
  43. ^ Hadley, Franklin (2007-06-07). "Goodbye wires…". MIT News. Massachusetts Institute of Technology. Archived from the original on 2007-09-03. Retrieved 2007-08-23.
  44. ^ Castelvecchi, Davide (November 15, 2006). "Wireless energy may power electronics: Dead cell phone inspired research innovation" (PDF). TechTalk. 51 (9). Massachusetts Institute of Technology. Archived (PDF) from the original on March 2, 2007. Retrieved August 23, 2007.
  45. ^ a b Young Jae Jang (2018), "Survey of the operation and system study on wireless charging electric vehicle systems", Transportation Research Part C, 95 (95): 844–866, Bibcode:2018TRPC...95..844J, doi:10.1016/j.trc.2018.04.006
  46. ^ Tom Fogden (September 10, 2021), "Tomorrow's Wireless Charging Taxis – Mobility Moments With Sprint Power Director Ben Russell", autofutures.tv, archived from the original on October 18, 2021, retrieved April 3, 2022
  47. ^ Laurent Miguet (April 28, 2022), "Sur les routes de la mobilité électrique", Le Moniteur
  48. ^ US527857A, Maurice Hutin and Maurice Leblanc, "TRANSFORMER SYSTEM FOR ELECTRIC RAILWAYS", published 1894-10-23 
  49. ^ Hubbard, Nate (September 18, 2009). "Electric (Car) Company". Wytheville News. Archived from the original on January 11, 2013. Retrieved 2009-09-19.
  50. ^ Thibaut, Kyle (22 March 2011). "Google Is Hooking Up Their Employees With Plugless Power For Their Electric Cars (Video)". TechCrunch.com. Techcrunch. Archived from the original on April 2, 2015. Retrieved March 6, 2015.
  51. ^ "EV1 Club Home Page". EV1 Club. Archived from the original on 2008-06-03. Retrieved 2007-08-23. GM Pulls the Plug on Inductive Charging: Letter from General Motors Advanced Technology Vehicles (Letter dated 2002-03-15)
  52. ^ "Rulemaking: 2001-06-26 Updated and Informative Digest ZEV Infrastructure and Standardization" (PDF). title 13, California Code of Regulations. California Air Resources Board. 2002-05-13. Archived (PDF) from the original on 2010-06-15. Retrieved 2010-05-23. Standardization of Charging Systems
  53. ^ "ARB Amends ZEV Rule: Standardizes Chargers & Addresses Automaker Mergers" (Press release). California Air Resources Board. 2001-06-28. Archived from the original on 2010-06-16. Retrieved 2010-05-23. the ARB approved the staff proposal to select the conductive charging system used by Ford, Honda and several other manufacturers
  54. ^ "EPCOT's Universe of Energy Companion Site: Pavilion". progresscityusa.com. Retrieved 2022-04-22.
  55. ^ "London charges ahead with wireless electric vehicle technology". Source London, Transport for London. November 10, 2011. Archived from the original on 24 April 2012. Retrieved 2011-11-11.
  56. ^ "First Electric Vehicle Wireless Charging Trial Announced for London". Qualcomm Incorporated. November 10, 2011. Retrieved 2011-11-11.
  57. ^ Knox, Annie. "University of Utah electric bus runs on a wireless charge". Salt Lake Tribune. Archived from the original on December 20, 2016. Retrieved December 17, 2016.
  58. ^ "UTA Announces Plans to Add First All-Electric Buses to Fleet". Ride UTA. Utah Transit Authority. Archived from the original on 20 December 2016. Retrieved 17 December 2016.
  59. ^ "Wirelessly charged electric buses set for Milton Keynes". BBC. January 9, 2015. Archived from the original on January 14, 2015. Retrieved 2015-01-08.
  60. ^ Bombardier Mannheim (2015-09-17). "Experts convinced by PRIMOVE solution for cars". Bombardier. Archived from the original on 2016-04-05. Retrieved 2015-09-17.
  61. ^ Sybille Maas-Müller (2015-03-12). "SITE FACT SHEET Mannheim Germany" (PDF). Bombardier. Archived from the original (PDF) on 2016-04-05. Retrieved 2015-03-12.
  62. ^ IPT Technology ENRX (May 20, 2022), "IPT - 25 years in 2 minutes", YouTube
  63. ^ "New hybrid bus charging technology trial announced". Transport for London. Archived from the original on 24 August 2016. Retrieved 2 December 2016.
  64. ^ Bacque, Peter (January 6, 2014). "Evatran to begin shipping its Plugless electric vehicle charging system". Richmond.com. Retrieved March 6, 2015.
  65. ^ "Videos - Wärtsilä".
  66. ^ "Wireless Charging Tech to Keep EVs on the Go". IEEE Spectrum: Technology, Engineering, and Science News. 27 August 2020. Retrieved 2020-09-29.
  67. ^ Ryan Mulligan (November 28, 2025), "King of Prussia's InductEV to be acquired by Israeli firm for $10.5M", Philadelphia Business Journal
  68. ^ Ridden, Paul (August 20, 2009). "Korean electric vehicle solution". New Atlas. Archived from the original on April 5, 2017.
  69. ^ H. Feng, R. Tavakoli, O. C. Onar and Z. Pantic, "Advances in High-Power Wireless Charging Systems: Overview and Design Considerations," in IEEE Transactions on Transportation Electrification, vol. 6, no. 3, pp. 886-919, Sept. 2020, doi:10.1109/TTE.2020.3012543.
  70. ^ Kwak Yeon-soo (March 24, 2019). "ICT minister nominee accused of wasting research money". The Korea Times.
  71. ^ a b Martin G. H. Gustavsson (March 5, 2021), Research & Innovation Platform for Electric Road Systems (PDF), RISE, ISBN 978-91-89385-08-5
  72. ^ Konstantinou, T.; et al. (2021), Feasibility study and design of in-road electric vehicle charging technologies, Purdue University, doi:10.5703/1288284317353
  73. ^ A. Wendt et al., "Wireless Electric Road Systems – Technology Readiness and Recent Developments," 2024 IEEE Wireless Power Technology Conference and Expo (WPTCE), Kyoto, Japan, 2024, pp. 177-182, doi: 10.1109/WPTCE59894.2024.10557264.
  74. ^ F. Chen, N. Taylor, R. Balieu, and N. Kringos, “Dynamic application of the Inductive Power Transfer (IPT) systems in an electrified road: Dielectric power loss due to pavement materials,” Construction and Building Materials, vol. 147, pp. 9–16, Aug. 2017, doi: 10.1016/j.conbuildmat.2017.04.149
  75. ^ Danial Arzjania; et al. (May 4, 2025), "Evaluating the structural performance of eRoad pavements: impact of inductive charging coils on mechanical behaviour", Road Materials and Pavement Design, 26: 55–71, doi:10.1080/14680629.2025.2492142
  76. ^ Pierre Hornych (October 11, 2024), "Advancing road-based charging for electric vehicles", Fall 2024 Kent Seminar Series
  77. ^ Yong Zhi, Cheng; Ji, Jin; Wen Long, Li; Jun Feng, Chen; Bin, Wang; Rong Zhou, Gong (2017). "Indefinite-permeability metamaterial lens with finite size for miniaturized wireless power transfer system". AEU - International Journal of Electronics and Communications. 12: 1777–1782.
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