Fujitsu announces development of wireless recharging technology

Researchers at Fujitsu have made huge steps toward developing effective magnetic resonance-based wireless charging systems for mobile devices.

We're all aware of how annoying a tangled mass of electrical wires can be. Fortunately, a research effort from Fujitsu is tackling the problem at its very source. During a conference held in the Institute of Electronics, Information and Communication Engineers at Osaka Prefecture University, the Japanese electronics giant announced a major step in developing a wireless recharging technology that can work simultaneously with multiple portable devices.

Researchers have been struggling with wireless electricity for some time now, and have come up with a number of different possible solutions, most of which are only at a prototype stage because of technological hurdles that can't be circumvented. As far as wireless charging goes, the two most popular solutions are electromagnetic induction and magnetic resonance.

Electromagnetic induction works by creating a magnetic flux between a power-transmitting and a power-receiving coil. While this is a promising technology for some applications, and particularly for recharging electric cars, it also seems to lack some flexibility since it only works over short distances, and the power transmitter and power receiver need to be in alignment for the system to work properly.

By contrast, the magnetic resonance method appears much more versatile, as it can transport electricity from a single transmitter to multiple receiving devices over a range of several meters and regardless of the relative position of the two ends.

While better in theory, the development of magnetic resonance has been hindered by practical design issues: a number of factors — parasitic capacitance, external magnetic fields, even the batteries in the device to be charged can influence the magnetic fields and drastically decrease the charging efficiency. Furthermore, the smaller the devices, the more they are subject to external influences, making this technology particularly hard to incorporate into mobile phones.

All these issues can be sorted out by properly designing the charging system, but the process takes time. In fact, the development of wireless charging for portable electronics has so far been hindered mainly by problems associated with design and analysis of the systems themselves.

What the Fujitsu researchers developed is essentially a sophisticated simulator that takes into consideration the coil model and the magnetic resonance conditions. This tool can guide manufacturers' decisions in setting the parameters of the wireless chargers in such a way to maximize the charging efficiency for multiple transmitters and receivers even for devices, such as mobile phones, that used to be problematic because of their small size.

The tool, which reportedly reduces design time by a whopping factor of 150, was used to design a compact power receiver and to manufacture prototype mobile phones with built-in wireless charging. The mobile phones can get charged from anywhere within the transmitter's range, reaching 85 pecent efficiency.

Fujitsu said it will use this technology to develop wireless charging systems for mobile phones and other portable devices, which should hit the shelves in 2012. The company is also looking to apply the technology for power transmission between computer chips and to provide mobile charging systems for electric cars.

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