Power transfer goes wireless at MIT

Technology demonstration lights a 60-W light bulb from a power source 7 ft away

A team from MIT’s Department of Physics, Department of Electrical Engineering and Computer Science, and Institute for Soldier Nanotechnologies has experimentally demonstrated a wireless power transfer technology by driving a 60-W light bulb from a power source 7 ft away. “WiTricity” (wireless electricity) technology is not based on RF or directed electromagnetic energy, but rather on magnetically coupled resonance.

A team from MIT has demonstrated a wireless power transfer technology.

Two objects of the same resonant frequency tend to exchange energy efficiently, while interacting weakly with extraneous off-resonant objects. The team explored a system of two electromagnetic resonators coupled mostly through their magnetic fields; they were able to identify the strongly coupled regime in this system, even when the distance between them was several times larger than the sizes of the resonant objects.

The experimental design consists of two copper coils, each a self-resonant system. The sending unit fills the space around it with a nonradiative magnetic field oscillating at MHz frequencies, mediating the power exchange with the receiving coil specially designed to resonate with the field. The advantage is that most of the power not picked up by the receiving coil remains bound to the vicinity of the sending unit, instead of being radiated into the environment and lost. For more information, visit http://web.mit.edu/newsoffice/2007/wireless-0607.html.

Alix L. Paultre