Disney could someday deploy the far-field wireless charging tech in its amusement parks
Disney Research has invented a new method of wirelessly charging mobile devices that could someday allow amusement park patrons to walk about freely while also getting their mobile devices charged.
The technology, which Disney has dubbed "quasistatic cavity resonance" (QSCR), enables purpose-built structures such as cabinets, rooms and warehouses to generate quasistatic magnetic fields that "safely deliver kilowatts of power to mobile receivers contained nearly anywhere within."
Disney's wireless charging technology research was published in the peer-reviewed journal PLOS ONE.
Disney Research isn't the first company to create wireless charging at distance, or far-field wireless charging. Start-ups Ossia and Energous have demonstrated wireless charging beyond 15 feet.
Both Energous' WattUp and Ossia's Cota mobile device charging systems work much like a wireless router, sending radio frequency signals that can be received by enabled mobile devices, such as wearables and mobile phones. A small RF antenna in the form of a PCB board, an ASIC and software comprise the wireless power receivers.
Disney Research uses a magnetic resonator coil, not unlike those used by conventional resonant wireless charging or "near-field" technologies sold today, to project a field at distance through which devices can receive power. In the center of an experimental room stands a copper pipe with capacitors that transmit the electrical current.
An experimental demonstration showed that in a 16×16x7.5-ft room with a floor, ceiling and walls made of painted aluminum sheet metal, the QSCR could deliver power to small coil receivers in nearly any position with 40% to 95% efficiency. Up to 1900 watts of power can be transmitted safely between transmitters and a coil receiver in a mobile device, "enabling safe and ubiquitous wireless power," the company said in its research.
In the future, Disney said, the amount of aluminum used in a space to create the magnetic field can be reduced by optimizing the QSCR, "and retrofitting of existing structures will be possible via modular panels or conductive paint.
"Ultimately, QCSR based wireless power offers a viable method for eliminating the wires and batteries that have limited many innovative solutions in the industrial, medical, and consumer electronic spaces while providing an unprecedented amount of spatial charging freedom," the company said.
At the turn of the last century, Nikola Tesla routinely demonstrated far field wireless power transfer using what is typically called the "Tesla coil."
In recent years, regulatory agencies have adopted strict safety guidelines for the use of far-field magnetic resonance devices like the Tesla coil.
"This has resulted in a long-standing tradeoff between the range at which a device can be wirelessly powered and the maximum amount of power that can be safely delivered," Disney Research said. "These far-field wireless power techniques have not found widespread use, since they are limited to delivering only a few milliwatts of power due to health and safety concerns."
Near-field magnetic resonance is a highly localized -- traveling a few millimeters to a few feet before transfer efficiency drops off rapidly as the source and receiver are separated by more than a coil diameter. "Likewise, it is not possible to strongly couple coils of drastically different sizes," Disney said.
Disney Research used far-field electromagnetic waves to generate uniform field patterns in a metallic chamber, which can create near-field standing waves for strong coupling to small receivers.
"This is accomplished by stimulating the resonant electromagnetic mode of a specially designed, enclosed metallic structure such that induced currents flowing through the walls, ceiling and floor are channeled through discrete capacitors. These oscillating currents in turn generate magnetic fields that permeate the interior of the structure, thus enabling wireless power transfer to receivers contained within, while simultaneously isolating the potentially harmful electric fields in capacitors."
This story, "Disney Research demonstrates open-air wireless charging" was originally published by Computerworld.
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