Disney's Roomscale Wireless Charging..

Wireless power is an idea that came into main stream ever since from 1891, when Nikola Testla demonstrated that you could transfer power between two objects via electromagnetic field. But it took over a century for the technology to find its own way, in the past few years wireless charging has finally emerged onto the consumer electronics market. But existing wireless charging is facing two challenges: range and health concerns. Safe, non-radiative methods such as near-field coupling are highly localized and require the devices to be placed near the charging source. It interrupts freedom and Charging is restricted to a confined area. Scientists at a branch of the Walt Disney Company called Disney Research have found a way to tackle these problems and charge devices on a room-scale without using any wires.

Disney has created a prototype living room where10 objects, a smartphone, a lamp, a fan, an RC car, and more are powered, without using any cables. The room built was lined with aluminum panels. In its center was a copper tube between the floor and the ceiling, with a current running through it. Fifteen capacitors in the pole are used to set a resonant frequency in the room and isolate electric fields from a signal generator, which outputs at 1.32 MHz. A uniform magnetic field is then run through the room at the same frequency. The receivers use a coil of wire to resonate at the same frequency, providing power to a device. The researchers were able to deliver about 1,900 watts with an efficiency of 40 to 95 percent.

Unlike existing wireless power transfer solutions, which mostly require an object to be placed very close to a wireless charging pad, the objects in Disney's living room can receive power while freely roaming; you can walk into the room with a smartphone in your pocket and it will start charging.The efficiency of the system is quite high, between 40 and 95 percent, depending on the receiver's position within the room.

The technology called as quasistatic cavity resonance (QSCR), can enable 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. A theoretical model of a quasistatic cavity resonator is derived, and field distributions along with power transfer efficiency are validated against measured results. Alanson Sample, associate lab director & principal research scientist at Disney Research said this new innovative method will make it possible for electrical power to become as ubiquitous as WiFi.

Following are the disadvantages in this system:

1. The circular nature of the magnetic field produced means receivers only work when at right angles to it,. i.e, ,if you want to receive power while freely moving around the room create a new receiver design that consists of three orthogonal coils, so that one of them is always able to receive power.
2. Safety-wise: to stay within the SAR limits, a measure of how much energy is absorbed by the human body,no humans can stand within 46 centimetres of the copper pole. Need of safety strategies such as intrusion detection or a decorative walls around the pole, right in the middle of the room.
3. Due to the large amount of unused power stored in the room, the appliances in the space would have to use and receive that much power. Some kind of real-time power consumption tracking, would be required to use1,900 watts in the room, you also need devices to be using this to remain safe.

Disney Research isn't the first company to create wireless charging at distance, or far-field wireless charging but the thing to be noted is that they used 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. A copper pipe with capacitors that transmit the electrical curren stands in the center of an experimental room.
Eventhough this system is far from commercial ready, it’s no less impressive and as they develop it further in the coming years, may soon extend to many more applications. For instance, electric buses wireless charging stations into public locations so that people with so-called battery anxiety can be relaxed. QCSR based wireless power offers a viable method for eliminating the wires and batteries, which can be restricted various imaginative arrangements in the mechanical, restorative, and customer electronic spaces while giving an anticipated measure of spatial charging flexibility. I must say it’s the most feasible yet. In addition, Disney aims to have Audio-Animatronics figures, which able to run throughout the day via wireless power source.