Sony develops an efficient system for wireless electricity transfer

It seems like science fiction, but it is not. Numerous work groups and R&D companies are betting heavily on the development of wireless electricity. Now, Sony has unveiled its proposal based on magnetic resonance that stands out for its high energy efficiency, being capable of transferring 60 watts of electricity at a distance of, for the moment, half a meter.

Sony Corporation está trabajando intensamente en un interesante desarrollo encaminado a enviar electricidad, un eficientísimo sistema inalámbrico de transferencia de energía que evita tener que usar cables de alimentación en dispositivos electrónicos tales como televisores. Con este sistema, es posible llevar hasta 60 vatios de energía eléctrica sin cable alguna a una distancia de 50 cm. Su eficiencia es de aproximadamente 80% y de aproximadamente 60% cuando se incluye un rectificador.

El nuevo sistema inalámbrico de transferencia de energía incorpora una forma de tecnología de transmisión de energía eléctrica sin contactos, basada en la resonancia magnética. Con la resonancia magnética, la energía electromagnética es sólo transferida a dispositivos receptores que comparten las mismas frecuencias resonantes de la fuente de energía, de manera que se mantiene la eficiencia de transferencia de energía, incluso cuando hay desalineamientos. Por otra parte, incluso si hay objetos metálicos situados entre el transmisor y el receptor, no hay inducción térmica.

Sony has also leveraged its many years of experience in developing high frequency radio frequency technologies for use in wireless communications and broadcasting products to create a new rectifier that realizes both high speeds and high levels of efficiency. The new wireless power transfer system combines these technologies to deliver a transfer efficiency of 60%, even when a rectifier is included. Sony has also developed passive expander units configured at the same frequencies as the transmitting and receiving devices, allowing the transfer distance to be extended from 50 to 80 cm without degradation of transmitting efficiency.

With the increase in networked products, the number of cables used to connect these products has also increased. While data cables are rapidly being replaced by wireless communication systems, such as Wi-Fi, demand for wireless power transfer systems continues to grow as well. Sony will continue its efforts to develop other technologies that meet customer needs for transferring energy over a wide range of products, distances and energy levels.

Minimum energy loss

Sony has drawn on its long experience and expertise in radio frequency technologies and incorporated new optimal components to develop a new rectifier that combines high speeds and high levels of efficiency. This achievement minimizes energy loss when transferring it from the transmitter to the receiver, and allows products such as televisions or laptops to be powered efficiently wirelessly.

Extendable distance

Con el uso de unidades expansoras pasivas situadas entre el transmisor y el receptor es posible extender la distancia de transferencia sin degradación de la eficiencia. En experimentos llevados a cabo por Sony usando sólo dispositivos componentes, la distancia de transferencia ha podido ser extendida de 50 cm a 80 cm. Aun cuando generalmente se requieren transmisores y receptores relativamente grandes para transferir energía en distancias largas, las unidades expansoras pasivas pueden usarse para retransmitir energía entre un transmisor pequeño y unidades receptoras.

Un reto perseguido desde hace años

Although Sony has managed to reduce one of the biggest obstacles of the system, the loss of energy efficiency, the truth is that several institutions and R&D companies have been researching this wireless electricity for years. One of the work groups that first successfully carried out the experience was a team from the Physics department of the Massachusetts Institute of Technology (MIT) that managed to light a 60W light bulb using copper coils located two meters away from it. The members of this working group, Andre Kurs, Aristeidis Karalis, Robert Moffatt, and professors Peter Fisher and John Joannopoulos) managed to bring electricity without cables, but with the disadvantage of losing almost half of the energy on the way between the emitting coils and the bulb.

The 'secret' of these experiments is found in the magnetic resonance that makes a certain object vibrate when energy of a certain frequency is applied to it. When two objects have the same resonant frequency (generally below 10 Mhz) they exchange energy without destroying the objects located around them. 'Witricity' uses the resonance of electromagnetic waves with a very low frequency, exactly 10 Mhz.

In addition to Sony, other companies like MIT are investing large amounts of funds in improving the system, even some companies like MIT have already named this system: WiTricity. Its CEO Eric Giler showed its results in public for the first time at the TED (Technology, Entertainment, Design) Convention organized by this academic organization last summer in Oxford.