Fujitsu Develops Power Transmitter For Mobiles, Cars

Fujitsu Laboratories said on Monday it has overcome a key design challenge in the manufacture of wireless chargers based on a technology called magnetic resonance, paving the way for such devices to become widespread by 2012.

Chargers based on magnetic resonance could allow charging at a distance of up to several meters and could work with something as large as an electric vehicle, Fujitsu said. Such chargers don’t require the transmitter and power receiver to be in alignment, meaning that several devices could be charged at the same time.

The technology competes with techniques such as electromagnetic induction, used as the basis for the Qi standard announced by the Wireless Power Consortium earlier this month. That technology has limitations including the necessity for the device to be charged to be within close range.

Design challenge

Wireless charging is considered by some to have environmental benefits to the extent that it encourages the use of rechargeable batteries, as opposed to disposable batteries.

In the US, for instance, consumers purchase 3 billion disposable dry-cell batteries every year, in a worldwide market of 15 billion, with 2.8 billion of them going into landfills each year.

The efficiency of wireless charging has in the past been relatively low, on average around 60 percent, according to figures cited by research and consulting firm Frost & Sullivan. On the other hand, typical corded mobile phone chargers have an efficiency of at least 80 percent, according to figures cited by green consultancy Ecos Consulting. Fujitsu said a prototype mobile phone charger operated at 85 percent efficiency.

Thus far a problem holding back the development of magnetic resonance-based chargers is that the chargers must be carefully configured to avoid causing interference in the devices to be charged. The tuning process has meant that such chargers are too time-consuming to develop, according to Fujitsu.

The company said it has now developed a simulator greatly speeding up the tuning process.

“These technologies represent the world’s first practical magnetic resonance design simulator, which enables rapid and precise designs for transmitters and receivers according to the desired resonance requirements,” Fujitsu said in a statement. “Manufacturers will be able to design charging systems in 1/150th of the time currently required.”

Prototypes

Fujitsu said it used the simulator to design a compact power receiver and to manufacture prototype mobile phones with built-in wireless charging.

“The prototype mobile phones can charge anywhere within the power transmitter’s range, regardless of their position in reference to the transmitter, with 85 percent efficiency,” Fujitsu stated.

The technology could be used to transmit power between circuit boards or computer chips, or could be used to build charging points under roads for the recharging of electric vehicles.

The company is to present the details of its research on Tuesday at a conference of the Institute of Electronics, Information, and Communication Engineers (IEICE) at Osaka Prefecture University in Japan.