Witricity, Wireless Electricity Technology: The Concept, Applications and Future

WiTricity, The Wireless Electricity means a Future without Power Cables. Imagine Laptops, Cell Phones, MP3 Players, household Robots and other Portable Electronic Appliances automatically being charged without plugging.

The idea of Wireless Power Transfer is motivated by the shortcoming of revolutionary autonomous electronic devices and gadgets that have become an integral part of our lives. But the Physics Principles for such provisions were always existing in the nature. A conclusion drawn by MIT Researchers working on the feasibility of using resonant objects, strongly coupled through the tails of their non-radiative modes, for few meters mid-range Wireless Power Transfer applications.

Witricity, The Wireless Power Transfer

Witricity is portmanteau term coined for wireless electricity. With Electricity being the life of modern world living, and conventional use of electricity made possible through the wires, researchers at MIT devised a means of providing electricity without wires.

The Witricity works on the principle of using coupled resonant objects for the transference of electricity to objects without using any wires. A typical Witricity system consists of a Witricity Transmitter and Receiver, same as the transfer of Electromagnetic waves in Radio Transceivers systems.

Witricity is rooted in such well-known laws of physics that it makes one wonder why no one thought of it before. Prof. Joannopoulos, an MIT researcher points out the reason:

In the past, there was no great demand for such a system, so people did not have a strong motivation to look into it. Over the past several years, portable electronic devices, such as laptops, cell phones, iPods and even household robots have become widespread, all of which require batteries that need to be recharged often.

Witricity make use of Resonant Magnetic Field in the range of 100 watts initially. This is unlike the principle adopted by Nikola Tesla in the later part of the 19th century; where conduction based systems were used.

In initial experiments, researchers powered a 60 watt light bulb from a Witricity Power Source located at the distance of 2 meters with great efficiency.

Research and Development at MIT

The first successful experiment of witricity, the concept of wireless electricity, was conducted in the year 2007, in Institute for Soldier Nanotechnologies at Massachusetts Institute of Technology (MIT), lead by Prof. Marin Soljacic and Prof. John Joannopoulos. This work was funded by the Army Research Office, National Science Foundation and Department of Energy, USA.

This experiment was done using two feet diameter copper coils, a 10 MHz transmitter that was attached to a power source and a receiver that was placed about seven feet from the transmitter. This receiver was attached to a light bulb and once power was switched on at the transmitter, the bulb lit up without any physical connection.

Data collected through measurements showed that there was transference of 40% of electricity through Witricity, successfully passing through obstacles like wood, metal and concrete.

In a Witricity Systems, the transmitter resonates with a certain low frequency electromagnetic energy waves. While the objects having a Witricity receiver with same resonance frequency tend to receiver that energy . Just like in acoustic resonance, where there is a chance of a glass breaking if you strike the right tone. Low frequency electromagnetic waves are safe for human body unlike electric waves which are strongly harmful to human body.

Witricity Applications

Witricity Applications are expected to work on the anything and everything rechargeable that is in close proximity to a source of wireless power without the need of being plugged in.

The first Wireless Powering System to market was an inductive device, much like the one Tesla saw in his dreams, but a lot smaller. It looks like a mouse pad and can send power through the air, over a distance of up to a few inches. A powered coil inside that pad creates a magnetic field, which as Faraday predicted, induces current to flow through a small secondary coil that's built into any portable device, such as a flashlight, a phone, or a BlackBerry. The electrical current that then flows in that secondary coil charges the device's on-board rechargeable battery. (That iPhone in your pocket has yet to be outfitted with this tiny coil, but, as we'll see, a number of companies are about to introduce products that are.)

The practical benefit of this approach is huge. You can drop any number of devices on the charging pad, and they will recharge wirelessly. No more tangle of power cables or jumble of charging stations. What's more, because you are invisible to the magnetic fields created by the system, no electricity will flow into you if you stray between device and pad. Nor are there any exposed "hot" metal connections. And the pads are smart: Their built-in coils are driven by integrated circuits, which know if the device sitting on them is authorized to receive power, or if it needs power at all. So you won't charge your car keys. Or overcharge your flashlight.

The dominant players in Witricity Technology Products and Services are:

1. WiTricity Corporation, Watertown, MA
2. Fulton Innovation, Michigan, US
3. WiPower, Florida, US

They are regularly unveiling a range of wirelessly charged consumer products at the Consumer Electronics Shows for last two years. Fulton's new pad-based eCoupled systems are being used by police, fire-and-rescue, and contractor fleets an initial market of as many as 700,000 vehicles. The system is being integrated into a truck console designed and produced by Leggett & Platt, a $4.3 billion commercial shelving giant; it allows users to charge anything from a compatible rechargeable flashlight to a PDA. The tools and other devices now in the pipeline will have a support from companies such as Bosch, Energizer, and others. Companies such as Philips Electronics, Olympus, and Logitech are creating standard for their products to be compliance with this new Witricity technology. A step toward making Witricity as product standard feature like we have already seen in the case of Bluetooth, WiFi support features.

Here under are few domestic, industrial, transportational and other Applications areas for Witricity:

1. Automatic wireless charging of mobile electronics (phones, laptops, game controllers, etc.) in home, car, office, Wi-Fi hotspots … while devices are in use and mobile.
2. Direct wireless powering of stationary devices (flat screen TV’s, digital picture frames, home theater accessories, wireless loud speakers, etc.) eliminating expensive custom wiring, unsightly cables and “wall-wart” power supplies.
3. Direct wireless powering of desktop PC peripherals: wireless mouse, keyboard, printer, speakers, display, etc… eliminating disposable batteries and awkward cabling.
4. Consumer Electronics Applications
5. Direct wireless power and communication interconnections across rotating and moving “joints” (robots, packaging machinery, assembly machinery, machine tools) eliminating costly and failure-prone wiring.
6. Direct wireless power and communication interconnections at points of use in harsh environments (drilling, mining, underwater, etc.) where it is impractical or impossible to run wires.
7. Direct wireless power for wireless sensors and actuators, eliminating the need for expensive power wiring or battery replacement and disposal.
8. Automatic wireless charging for mobile robots, automatic guided vehicles, cordless tools and instruments…eliminating complex docking mechanisms, and labor intensive manual recharging and battery replacement.
9. Automatic wireless charging for existing electric vehicle classes: golf carts, industrial vehicles.
10. Automatic wireless charging for future hybrid and all-electric passenger and commercial vehicles, at home, in parking garages, at fleet depots, and at remote kiosks.
11. Direct wireless power interconnections to replace costly vehicle wiring harnesses and slip rings.
12. Direct wireless power interconnections and automatic wireless charging for implantable medical devices (ventricular assist devices, pacemaker, defibrilator, etc.).
13. Automatic wireless charging and for high tech military systems (battery powered mobile devices, covert sensors, unmanned mobile robots and aircraft, etc.).
14. Direct wireless powering and automatic wireless charging of smart cards.
15. Direct wireless powering and automatic wireless charging of consumer appliances, mobile robots, etc.

Witricity: Wireless Power Future

Since Witricity is in the developmental stage with lots of improvement work still to be done, its potential applications are expected to materialize in the new future with few years time. Like every scientific invention, there are few controversies and debates attached to the benefits of the Witricity concept, including fears of a risky living with a power network running in the air around us in the home. However despite these contraindications, Witricity has a bright future with the many advantages it provides in terms of weight, convenience and portability of electrical appliances. As one of its inventors, Prof. Soljacic explains:

Once, when my son was about three years old, we visited his grandparent's house. They had a 20-year-old phone and my son picked up the handset, asking 'Dad! why is this phone attached with a cord to the wall?' That is the mindset of a child growing up in a wireless world. My best response was, 'It is strange and awkward, isn't it?' Hopefully, we will be getting rid of some more wires, and also batteries soon.