Since researchers from the MIT first announced that they had a working prototype of a wireless power supply in 2007, Japanese companies (and not only) sought to replicate and even surpass MIT’s results.
The Arakawa & Komurasaki Laboratory of the University of Tokyo together with DENSO Corp. of Japan released a paper discussing magnetic resonance, at the IEICE 2010 conference, held March 16-19.
According to professor Kimiya Komurasaki, the system that can be built by following the specifications written in the study can supply power to devices ranging from mobile phones to objects moving freely in space.
The researchers studied the link of the position of the magnetic resonator within the three-dimensional space to transfer efficiency, by using computer simulations and actual measurements. When the distance between the transmitter and the receiver changes, a coupling constant also changes, which in turn causes the whole system to re-adapt the impedance ratio accordingly. Measurements results confirmed the fact that impedance matching is vital in an efficient wireless power transfer.
One interesting application would be powering moving on-board sensors, where wiring is not possible or difficult due to harsh conditions (temperature, vibration), and efficiency is not imperative because the sensors operate at low power. Komurasaki believes the range of applications will expand, commenting “It will be possible to measure a variety of things in the car that we cannot measure now.”
“We wanted to escape the bonds imposed by MIT,” explains Takehiro Imura, Doctor’s Degree Candidate, Graduate School, of Engineering, Institute of Industrial Science, University of Tokyo, stating that their wireless power transmission system could be implemented from kHz to GHz frequencies. Since MIT first got out with their project in 2007, they were approached by several corporations and institutions, but they all relied on a 10 MHz frequency (although MIT never got stuck to that number).
The Japanese researchers are currently studying how they could improve microwave power transmissions (which could serve well in power transmissions from orbital solar harvesting satellites). Their first efficiency result was 83.7% in simulations, and 76% in real life.
The first useful wireless power transmissions were accomplished by Nikola Tesla, in early 1900s. Since then, it’s been nothing but small steps in this field…