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Gov't Researchers Develop Wireless Car Chargers That Are Faster Than Plug-ins (computerworld.com)
An anonymous reader quotes a report from Computerworld: The U.S. Department of Energy has demonstrated a 20,000 watt (20KW) wireless car-charging system that offers three times the efficiency of today's plug-in systems for electric vehicles (EVs). The research is the first step in creating a 50KW wireless charging system that may someday allow roadways to charge vehicles while they are being driven. The DOE's Oak Ridge National Laboratory (ORNL) in Tennessee demonstrated the new system in partnership with Toyota, Cisco Systems, Evatran and the Clemson University International Center for Automotive Research. ORNL said the 20KW charging system for passenger cars is the world's highest power wireless system. It was developed in less than three years using a "unique architecture that included an ORNL-built inverter, isolation transformer, vehicle-side electronics and coupling technologies."
A Tesla charger has an efficiency of over 90%. If this charger has an efficiency three times that, then it should be above 270%. Maybe it can feed the extra 170% back into the grid.
The actual quote from the article is " achieved 90 percent efficiency at three times the rate of the plug-in systems commonly used for electric vehicles today.", not three times the efficiency. They're comparing the charger to a typical home charger. Which is meaningless since the system isn't limited by the connection to the car. And think about it. 10% loss of charging energy so you don't have to go to all the trouble of plugging it in? What a waste of our tax dollars.
Can't find any clue as to what frequency is being used for the charger. The prospect of 50 kW of power in your garage or wherever is worrying, despite being "well shielded". Even if it's a lower frequency (in the kHz range), there will be harmonics all over the spectrum, putting radio amateurs and anyone else using sensitive radio gear in a bind.
Fiat Lux.
The wireless charging system is not faster than all plug-in chargers, just the ones commonly used at home. The charge stations available commercially are faster and the article mentions this. It is also not three times more efficient, it's 3x faster than the home charging systems. It's 90% percent efficient, which is impressive but I seriously doubt any charging system is only 30% efficient.
Think globally but act within local variable scope.
There's an abundance of research showing that strong electric and magnetic fields can be hazardous.
No there isn't.
It's also been shown that too much exposure [to MRI] causes cancer.
Total BS.
Who said a MRI is dangerous? Thousands of people have them every day with no increase in cancer risk.
If you bring a large chunk of metal in to the room then sure it's dangerous but that's more to do with the metal flying physically towards a magnet rather than cancer.
Yes yes, terrible summary.
The 'fun' part is the 10% coupling waste (versus I would imagine much less than 1% for plugin charging).
Remember, we are not talking about the battery charge efficiency here, their 10% is just for the transfer of power to the car..
So, thats 'only' 2kw continuous loss. Thank god everyone is converting their houses to LED lighting, which still wont
offset the losses here.
Go Progress!
50kw, or even 20kw is extremely dangerous to couple. Outside of the leaking RF spectrum possibly interfering with electronics, the danger is something with a similar resonant field could be nearby and absorb some of that power. Even just a few tens of watts could start a fire. They probably need something akin to a gfci circuit that monitors the power in and out precisely and if something is absorbing power that shouldn't be, notice the discrepancy and terminate the charge.
The actual picture is pretty funny, with a ginormous briefcase put under the back of the vehicle, a mere 2 inches above the similar unit embedded in the floor. No way is that remotely practical, they would need to increase the air gap by at least triple, to 5x+ to properly mount it under reasonable vehicles. To keep the same coupling, the size would then have to be increased substantially. Further there is no way in hell that is working while you drive, it has to be precisely aligned which isn't going to happen period, even at stoplights. I could see it embedded into a garage stall, or even a parking stall outdoors, perhaps, but alignment would be a major issue and one that is not being addressed at this stage from anything I can gather.
I think they usually monitor the procedure in real-time, adjusting the area being scanned, etc. I can't imagine why having a computer in the same room as a 1.5T superconducting magnet would be a bad idea...
Only crack the nuts that crack. You don't put the ones that don't crack in the sack.
There's an abundance of research showing that strong electric and magnetic fields can be hazardous.
Sure, like the electric field formed between clouds and the Earth, but only if you happen to be around when the field discharges.
Only crack the nuts that crack. You don't put the ones that don't crack in the sack.
You do realise that inside many DC-DC converters, and indeed inside all of the power transformers between the power station and your house, there are magnetically coupled coils that effectively transfer the energy "wirelessly".
The difference in this case is using an air cored coil at a greater distance. It's definitely harder to make them efficient but they have clearly shown great potential here, with 90% efficiency versus DC-DC converters at 95% and regular transformers at 98%.
As long as there is a properly installed quench tube to vent the boiling Helium and prevent it from filling the room, I don't see how a quench can kill or injure someone.
What would make sense is that someone went near the scanner with something magnetic, injuring/killing themselves or someone else, and resulting in an emergency shutdown of the field (i.e. a quench).
Alkaline batteries are dangerous too, if I eat them.
Only crack the nuts that crack. You don't put the ones that don't crack in the sack.
Not MRIs. When I did a paediatric anaesthesia fellowship we would routinely sit in the room for the scan. Think cardiac MRIs requiring breath holds. The techs sit outside the room cause they need to use computers to run the scanner and also it's really (unpleasantly Even with quality ear protection) noisy. Plus something about pressure in the room that I never understood.
...government charges YOU!!!
20kw is nowhere near three times the efficiency of an average charger.
Home chargers for Tesla offer 20kw (22kw in EU) for usual setup.
Superchargers offer a lot more - 135kw for Tesla superchargers, 50kw for regular EU charging stations.
Tesla Model S was the best selling EV in the US last year (yes, it outsold the next best - the Leaf, in number of units, not just sales $) - source http://insideevs.com/monthly-p....
Typical home charger for a Tesla is the mobile connector which delivers 10KW charging from a dryer outlet. Owners have an option to install a 20KW Tesla plug-in charger in their garages, which many people do. Tesla plug-in "superchargers" charge up to 120KW, so 20KW wireless is not 3 times the rate of any of those plug-in chargers (it's actually only 1/6th of the most powerful one). It probably is 3x the rate of the original, discontinued a couple of years ago, RAV4 EV charger, but saying it's 3x the rate of plug-in chargers used today is incorrect. Lastly, there are public chargers limited to ~6.6KW, but their limit is not because of the fact that they are wired, it's mostly their power source (the J1772 connector used by most of those can handle up to 20KW).
It would not need to be "magnetic" ( assuming you mean ferrous ), only conducting.
An aluminum bolt/rod/whatever in your person would still conduct, and moving thru a magnetic field, would have current induced in it.
That current, having nothing to do, would likely heat the component in question.
emt 377 emt 4
This is awesome news, but there is a threat here:
I'm fairly certain, that future technology will not allow anonymous charging. It could, but it will not — for the same gratuitous reasons you can't use and recharge a toll-paying transponder anonymously (the way you could use a phone-calling card, for example), but must associate it with both yourself and your car. (Well, New Hampshire, sort of, makes it possible to avoid providing your name, but the cars must still be listed in advance.)
And it is increasingly impossible to drive in certain places without such a transponder, which is, of course, routinely used for surveillance.
As happened with electronic toll-paying, the on-the-road charging too will go from optional to mandatory. Manufacturers will reduce the battery-sizes in many models to save weight and space — and how much of a charge do you need to get from the powered highway to your home (over unpowered streets), right? Effective tracking of your car will become possible. Worse, it may also become possible to remotely disable your car by revoking your access to these chargers.
Today's concerns over license-plate readers may then appear naively quaint...
In Soviet Washington the swamp drains you.
Then why do radiologists always stand behind lead-lined walls/glass when they operate the machines?
Radiologist doing MRI do not stand behind lead lined glass. The reason they stand outside of the imaging room is to keep sensitive equipment (computers) out of the magnetic field and prevent random pieces of metal in their pockets from accelerating towards the patient. You must be mixing MRI (magnetic resonance imaging, which uses nuclear magnetic resonance) with CT (computer tomography, which uses relatively high intensity X-ray).