An efficient way to transmit electricity through the air
In 2011, when she was a doctoral student in paleobiology at the University of Pennsylvania, Meredith Perry found herself wondering if the cumbersome cable that connected her laptop charger would ever be replaced by something more modern. She began looking for ways to make this idea a reality. She discovered that wireless energy transmitters based on magnetic resonance or induction already exist, but their range is limited. The problem with these transmitters is the fact that the intensity of the electromagnetic radiation decays characteristically as the square of the distance from the radiation source.
Mechanical vibrations, on the other hand, do not suffer from this problem. Therefore, using piezoelectric transducers that will convert the mechanical energy of air vibrations into electricity seems like a much better idea. Since sound is nothing more than vibrations of air particles, it is possible, at least in theory, to use sound waves to transfer energy. And sound at supersonic frequencies (ultrasound) would be perfect for this purpose because it is safe, quiet and carries a lot of energy.
When Perry presented this idea to professors at her university and elsewhere, many of them told her it was not feasible. Their claim was that it was simply impossible to extract enough energy from ultrasound waves to charge electronic devices and that any attempt to do so would involve it in a tangle of engineering problems, both from the electrical and acoustic aspects. "But I knew the math was right," she says. "And no one has provided me with conclusive evidence that this is indeed impossible." Perry therefore founded a company, uBeam, to develop the technology. The transmitter developed by the company, currently in the prototype phase, works like a directional speaker. It focuses ultrasound waves to create a concentrated point of energy; A receiver that is attached to an electronic device receives this energy and converts it into electricity. Perry plans to bring the first generation of its products to market within two years.
According to Perry, the universal wireless charging system will eliminate the countless chargers and cables that we currently have to drag with us everywhere and will allow mobile devices to perform energy-consuming operations without draining their batteries. With the disappearance of the charging cables, new possibilities for interior design will also be opened and the weight of airplanes, cars, spaceships or any other vehicle that is currently loaded with wiring for energy supply purposes will be reduced. "All in all, wireless charging will allow us freedom in our interactions with the physical world," Perry says. "She will cut off the thickets that are currently tying us to the wall."
The article was published with the permission of Scientific American Israel
13 תגובות
There is now a short section of road (several kilometers) in Britain, one of whose lanes is intended for charging an electric car, electro-magnetic charging while driving. Sounds very promising, the main problem is the cost of the infrastructure.
I got. You don't have to run after technology because it's there. Some prefer wireless charging and some don't.
I agree that wireless charging is unnecessary. Today I can use the phone while charging, and this time is relatively short.
In wireless charging, the device must be placed on the charger and cannot be used. And in addition - the loading is very slow.
Right. The charger is close to the cell phone.
The topic of electromagnetic wireless charging is hot today. This is a research topic today in universities in Israel, check 100%.
In addition, the advanced cell phones are charged this way. Until today I have not heard of electric acoustic charging but only of electromagnetic charging
The whole issue of wireless charging is irrelevant. A. There should be an energy transmitter nearby (tens of cm). Inside the phone or connected to it will be the energy receiver. third. Both need to be compatible with each other.
Joseph
In principle, you can put a microphone in front of a speaker and thus transfer energy, if the microphone is of the right type (dynamic microphone). It's very inefficient but it will work. If you make sure that the speaker and the microphone are in resonance then there will be a more efficient transfer of energy - think of the famous Tacoma Straits Bridge...
Nissim, you are right about your corrections. I know charging by electromagnetic radiation, not acoustic.
Joseph
You are mixing up a lot of concepts. There is no mention of a thermocouple anywhere, but a piezo-electric transducer. What detects an audio signal is called a microphone and not a speaker...
The frequency of ultrasound is in the megahertz range, and it is already possible today to transfer a lot of energy with this method. One of the uses is burning cancerous tumors with the help of such waves. In the past, this method was used in the treatment of breast cancer, and today it is also known to be used for brain tumors.
This is perhaps the big problem of the method, unlike a magnetic field that does not affect our body, an ultrasound beam will transfer its energy to anything that has mass.
I am open to innovations. I am skeptical about this invention and state in advance that this is only a personal opinion. Transferring energy by acoustic waves to a thermocouple is possible, but the energy of the basic sound packets, phonons - is small because of the wavelength, I guess about 40 kilohertz - not in the audible range. The energy of the fundamental quotient of electromagnetic waves, for example microwaves - measured in photons, is 100,000 to a million times higher.
Detection of an acoustic signal by an electric sensor is possible and it is done - it's a speaker. Generation of electricity by piezoelectric fabric I've heard about that too - I don't know if it's applicable.
But theoretically the idea is possible, so I give her credit. I'm not knowledgeable enough.
The way to criticize it - has the researcher published articles in the professional press on the subject. If so - then it is up to the researchers to review. In my opinion it is at the stage of a shirt that produces energy - impractical, they don't know how to store it yet. Can be applied in the future perhaps.
It reminds me of charging a toothbrush, already there.
Does anyone have any idea why, as they write, in radiation-based transmitters, the electromagnetic radiation decays characteristically as the square of the distance from the source of radiation, and in sound waves it doesn't? As far as I know, the reduction in intensity directly proportional to the square of the distance is due to the way a spherical wave disperses. This is valid for both electromagnetic sources and sound waves.
Nice invention. I just hope it won't cause all kinds of unexpected effects, such as adversely affecting dogs, bats, kidney stones and other formations that are known, or we don't know, how ultrasonic waves affect them.