What is the Future of Wireless Power?

mfbatzap writes "According to Firdooze, we have seen various devices that can free ourselves from wires at CES 2008. The manufactures, Wildcharge, Powercast and Fulton Innovation, came out with two different methods of transmitting power from source to the devices. Wildcharge and Fulton banked on magnetic coupling while Powercast decided to go with RF (Radio Frequency). So which technology will eventually prevail to be the future of wireless power? Or will the technological setbacks from transferring power wirelessly make it unrealistic to accomplish a wire-free world?"

Re:Out of curiousity...

[tjstork]

All fuels take more energy to produce... in a sense, our present fossil fuel predicament is because we are using stored energy from the sun over millions of years. That we can even think about creating biofuels or really, any sort of fuel, efficiently, says a lot for how far the technology has come. But we'll never be able to just "create" a fuel, and the world's going to have to accept that.

Re:Out of curiousity...

[MBCook]

I'd think you'd have problems with RF, it'd be easy to waste power that way. The magnetic people mentioned in the article say they've hit 98.5%, which is great.

Re:I say neither, you say neither

[Lumpy]

you dont need to shoot it across the room, just charge the device when set on a table. Make ALL your tables charging stations and now you attain the "wireless power" illusion.

I did this way back in the 90's for one of my EE projects. I created a charge mat and charge adapters to make devices charge from the mat. worked great, erased tapes , credit cards, and discs though... All you did was set the device down and it started charging. worked great and could supply 100ma of charge current to 3 devices.

omnidirectional wireless power

[sluke]

I'm relatively pessimistic about both of the technologies mentioned due to the inherent limitations that they pose (large leakage of radiated power or short range). I'm looking forward to seeing products based on the wireless power idea that came out of the Joannopoulos group at MIT in 2006.
The idea was that you can setup an RF wireless power transmitter in such a way that it does not actually transmit any power unless it resonantly couples to a precisely shaped receiver. This way there is little to no leakage and they claimed that the power transfer was quite efficient. I'm sure this was posted to slashdot, but I can't seem to find it. Here's a link to the paper if you are somewhere with access to Science: Science 6 July 2007: Vol. 317. no. 5834, pp. 83 - 86 [sciencemag.org] and here's [mit.edu] a link to the press release by the MIT news office (no subscriptions required).

It is simply a bad idea

[damburger]

There is one of two ways you can get power wireless with RF radiation:

1. Send it out in all directions. Incredibly wasteful and, because of the inverse square law, has to be so powerful it will interfere with other stuff.

2. Send it out in a narrow beam. I really wouldn't want to be standing in between a laptop and an outlet if this were the method...

Either way, I prefer living in a home that isn't a microwave oven.

It's called "WiTricity"

[replicant108]

As I mentioned elsewhere, the BBC named it as one of the 'technologies of the year' - The technology with impact 2007 [bbc.co.uk]

Re:Wireless power?

[Anonymous Coward]

Telsa was an absolute prodigy. It's a damn shame he is not more often mentioned in the history and school books!

Don't know who he is? Take 10 mins. and see that he is an equal to names like Einstein and Newton:
http://www.youtube.com/watch?v=gt8Y93k0pB0 [youtube.com]

Really, just do this, open your eyes!

He had wireless power working with his 'radiant energy' approach... almost with zero loss.

There is not a single student being taught the complete thing when it comes to EE. Maxwell's original theories have been simplified by Heaviside; this is why so many interesting behaviour of electrical systems is lost. As a result, this missing part of EE is not researched anymore.. at least not in public projects..

(Public) EE is still in it's infancy and free electricity is possible, 'from the very wheelworks of nature'.

Way better ideas

[Casandro]

Well first of all, the biggest untapped energy source on the planet still is an increase in efficiency. Why does my laptop need take 60 Watts of power in order to heat up my lap?
Why do we have displays in mobile devices that waste 5/6 of the light they generate?
Why do we still have processors that take _Watts_ of power althought alternatives with milliwatts are available?

I believe that a 1 Watt laptop-like device is definitely possible. It won't have a colour screen nor Windows Vista, but it would do everything you want it to do. Just look at old Psions which ran for months.

Re:omnidirectional wireless power

[Big_Breaker]

Sorry but you have this one wrong - converting mains AC to 1mhz is very easy. A common switch mode power supply chops the 50/60hz AC from the wall into a 100khz to 1Mhz waveform with a common (but fast) MOSFET. The chopped signal is then run through a stepdown transformer. The transformer and ripple filtering capacitors in the second stage can be MUCH smaller and more efficient due to the higher input frequency. In this way the high frequency generation is effectively free for a wireless power system, since most DC converter will have a high frequency first stage anyway.

The resonant coupling is the hard part. Switch mode frequency chopping is bog standard.

Re:Out of curiousity...

[Monkier]

Seems every one is more interested in your comment on biofuels. Me too :)

"A team of US researchers also found that switchgrass-derived ethanol produced 540% more energy than was required to manufacture the fuel."

http://news.bbc.co.uk/2/hi/science/nature/7175397.stm [bbc.co.uk]