• Nov 1, 2010

One could easily argue that parking between the white lines at any local hangout presents a challenge for some inexperienced drivers. So, why in the world would a company develop a system that forces drivers to align their vehicle over top of a 3,300 watt pad that's no bigger than a stop sign? The answer all boils down to simplicity. Delphi and WiTricity have teamed up to develop and market a wireless charging system for electric vehicles (EVs). Wireless charging uses an electromagnetic field to transfer energy between two objects. This action takes place without the need for a plug, and in the case of the Delphi-WiTricity design, will be activated the moment a vehicle is aligned with the charging pad below.

The system can charge battery-powered vehicles at a rate comparable to most home-based chargers, so we'd expect a full charge to take anywhere from two to eight hours depending on the vehicle's battery size. EV owners would only be tasked with parking their vehicles in alignment with the pavement-mounted pad and could then go about their day. Delphi envisions placing these charging systems in homes and embedded in company parking lots. One bump in the road still remains, though. Automakers, or some aftermarket company, will have to outfit battery-powered vehicles with a power capture resonator, and until that becomes a standard item on each and every EV, a nation dotted with wireless chargers remains just a dream.

[Source: Delphi Automotive]


Delphi Working to Make Electric Vehicle Wireless Charging a Reality

Revolutionary, green technology to help advance the establishment of a global infrastructure for electric vehicle charging

TROY, Mich. - Delphi Automotive has reached an agreement with WiTricity Corp., a wireless energy transfer technology provider, to develop automatic wireless charging products for hybrid and electric vehicles. The collaboration between the two companies will help establish a global infrastructure of safe and convenient charging options for consumer and commercial electric vehicles.

"This is groundbreaking technology that could enable automotive manufacturers to integrate wireless charging directly into the design of their hybrid and electric vehicles," said Randy Sumner, director, global hybrid vehicle development, Delphi Packard Electrical/Electronic Architecture. "Delphi's expertise in global engineering, validation and manufacturing coupled with WiTricity's patented wireless energy transfer technology uniquely positions us to make wireless charging of electric vehicles a reality."

Sumner said the wireless charging system would involve no plugs or charging cords. Drivers would simply park their electric vehicle over a wireless energy source that sits on the garage floor, or is embedded in a paved parking spot. The system will automatically transfer power to the battery charger on the vehicle.

According to Eric Giler, chief executive officer, WiTricity, their wireless system can already transfer over 3,300 watts - enough to fully charge an electric car at the same rate as most residential plug-in chargers.

"Charging an electric car should be as easy as parking it in your garage or parking spot," Giler said. "WiTricity's high efficiency wireless energy transfer technology is ideally suited for electric vehicle charging, and our partnership with Delphi will help to quickly get this technology deployed in OEM vehicles and infrastructure projects worldwide."

"Delphi can bridge the gap between the laboratory and the highway by providing E/E systems integration expertise, a global manufacturing and engineering footprint and high-voltage, high-power components specifically engineered for the hybrid and electric vehicles of today and tomorrow," Sumner said.

Wireless charging technology will need to co-exist with plug-in charging solutions, Sumner added, so that electric vehicle drivers have the ability to charge their vehicle when they are away from their wireless charging source.

Delphi also makes a Portable Electric Vehicle Charger that fits conveniently in the trunk of an electric vehicle. The user-friendly, UL-listed charging system plugs into any standard 120-volt outlet to enable safe electric vehicle battery charging at home or away. The charging unit can also be integrated into stationary charging applications.

About Delphi

Delphi is a leading global supplier of electronics and technologies for automotive, commercial vehicle and other market segments. Operating major technical centers, manufacturing sites and customer support facilities in 30 countries, Delphi delivers real-world innovations that make products smarter and safer as well as more powerful and efficient. Connect to innovation at www.delphi.com

About WiTricity Corp.

WiTricity Corporation designs, develops, manufactures, and markets patented technology for wireless energy transfer. Founded in 2007, the company is commercializing technology invented by a team of MIT physicists in 2006. This technology utilizes magnetism to transfer energy without wires in a way that is safe, efficient, and that works over distance. WiTricity is developing wireless energy transfer solutions for a broad range of consumer electronics, electric vehicle, medical, industrial, and military applications. For more information, visit www.witricity.com

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    • 1 Second Ago
      • 4 Years Ago
      Wow I can't believe I am just stumbling across this now. Ha I love this topic and have actually been working on this very technology for my thesis project. Some very interesting stuff coming about.

      Hermperez is correct in pointing out that WiTricity's use of electromagnetic induction is a far more efficient use of the technology at larger distances, plus with the added impact of showing no real health concerns. I question how can you not get excited about this. Not simply with the fact that you don't have to manually plug in your phone, camera, laptop, tv, coffee maker, but you don't have to physically manufacture the cords that go along with these electronics when you purchase them. What is the cost savings in that, not to mention the saved copper and recyclable factor of the unused cords we will have as a result of this technology. I mean who doesn't have a drawer full of random no-name cords that haven't been used in years.

      Its like if you were to get from one place to another. Would you A. Follow a distinct path and follow that to the end spot? or B. Fly directly there?
        • 4 Years Ago
        Answer? Probably which one cost cheaper... Ha but honestly I think the way this whole thing will work out will be dependent upon the devices. Mobile devices probably make since to be retrofitted with more distance charging such as WiTricity, while more stationary objects could get power through more surface to surface electromagnetic induction ... well at least not until efficiency comes up and cost goes down.
      • 4 Years Ago
      Well yeah that is one of the problems. Passenger vehicles have very different ground clearances. So each car would have its plate mounted at a different height. Unless you want to make things very complicated.
      • 4 Years Ago
      Ok maybe this is a stupid question but I am curious.....Is there any danger of electric shock in the space between the car and the floor?

      Would it maybe...kill a cat...that perhaps walked under the car to get warm?

      Seems like a good idea overall but wonder if there are any safety concerns.
        • 4 Years Ago
        Not really, there are very high energy densities in between the plates, but the efficiency is highly related to how close the plates are. A commercial system in use in Europe on buses gets to be less than an inch apart. Since they are so highly coupled, there's no chance for harm, even if someone with a modern pacemaker hugs the device. Safety isn't a problem, but cost is.
        • 4 Years Ago
        Great thanks for the information.
        • 4 Years Ago
        Nope, no risk of electric shock, the wireless transmission here isn't a harmful spectrum. You can use microwaves to transmit power wirelessly but that would present more of a danger issue to things like cats than magnetic waves. Unless there's magnetic material in them (like steel pins from surgery), this presents no threat to anything biological. It's the same as putting your hand on an induction stove. It doesn't get hot unless there's ferric (iron) material in the way (like a pot or pan).

        It'd probably be a warm little pad though, cats would probably love it! Another reason to have the wireless pads move up to meet the receiver.
      • 4 Years Ago
      Maaaan. You know when you have an idea and you're like "Wow! I should talk to a patent officer RIGHT AWAY!". Ya...

      This article is saying the biggest problem is a lack of the power receiver on the car but it's no more difficult (in fact less so) than installing a home charging station. It could be installed after production and an adapter could be fitted to the plug that still leaves it open to plugging in (no need to rewire). I saw it's easier to install since your car is mobile and you could take it to a garage to be installed instead of scheduling an expensive-as-hell electrician to come to your home.

      However, unless either the receiver moves down or the transmitter moves up (or a combination) to close the gap between the two, efficiency will be a problem. Intel has wireless power transmission record at 75% at a distance of 2-3 feet which is awesome, but even at closer distances, 90% transmission efficiency is a pipe dream at the moment. I'm pretty sure people would rather take a few seconds to plug in to get the near 100% transmission efficiency of a physical connection. Parking accurately isn't even that big an issue if the parking space has something in the way of guides or a little dip / blocks for your front or back tire to go into. Those lasers that you can install in your garage to help you park perfectly every time would finally have a use!
        • 4 Years Ago
        Yeah. Like a lowrider! Cue the Carlos Santana now, please!

        Just kidding. It would be a simple matter to lower the magnetic receiver pad on the bottom of the vehicle. Nothing built into the street should be required to move: too much maintenance and expense.

        How could it move? Inflatable/deflatable air bags. A screw drive actuated by an electric motor. A cable pulley mechanism. Etc.
        • 4 Years Ago
        I like the inflatable bag idea. a robust rubber cylinder with the right wall thickness and a small vacuum pump would do it.
      • 3 Years Ago
      The concept shows you're thinking, the model shows you not thinking hard enough. The PLUG & PLAY system now is the easiest. Don't make it harder so the sake of technology. The idea that MONEY would have to be spent to install the "source" into the ground the a "capture" into a vehicle is a pointless step. What if someone parks in your space? What if it's a snowy day? What if you run over a small child on a bike and he gets stuck to the CAPTURE under your car. Who pays to repair that? poor kids paper route makes less money than you daily latte! Improve the current electrical devices before taking a step into trivial forms of power dispersion. Low cost, quick-chargers and car chargers for affordable cordless lawn care machines. (Mowers, trimmers, clippers etc...) Cordless POWERFUL vacuums. How about a regular electric car that runs on common 12v car batteries and 4 alternators hooked up to the wheels!? Easy and cheap to replace and charge. We currently eat with our mouths - are you going to tell us we should try stuffing food into other orifices or can we stick with the proven method?
      • 4 Years Ago
      "Wireless charging works by using a low-density magnetic field to create friction that generates electricity." That's brilliant! I wonder if the friction from rubbing two sticks together would generate much electricity.
        • 4 Years Ago
        I was wondering if I was the only person who noticed that.

        Friction Eric, really? Friction?

        Probably in your line of work, if you don't understand something you should just not say anything.

        How about "current on one set of looped wires (in the pad) produces an oscillating magnetic field, which when passed through another set of looped wires (in the car), inducing a current in them".
      • 4 Years Ago
      This is not the usual inductive coupling of an airgap transformer.


      "In particular, WiTricity is based on using 'strongly-coupled' resonances to achieve a high power-transmission efficiency. Aristeidis Karalis, referring to the team's experimental demonstration, says that "the usual non-resonant magnetic induction would be almost 1 million times less efficient in this particular system".[3] The researchers suggest that the exposure levels will be below the threshold for FCC safety regulations, and the radiated-power levels will also comply with the FCC radio interference regulations."
      • 4 Years Ago
      Resonant inductive power transfer is a hoax. It's just a smart technique of building up large enough magnetic fields (on both sides) without exerting much stress on electronics. There's no magic, though, in order to transfer tens of kW's of power across some decent distances generated magnetic fluxes must be absolutely huge (and of fairly high frequency too).

      There are some serious concerns about safety and EMI here. They are all being dismissed without consideration with a single word "safe". Not entirely convincing, taking into account that these devices generate larger magnetic fluxes than anything but MRI (which is DC), are to be used in uncontrolled environments by unqualified people and for extended periods of time.

      Besides, why would anyone want to have such a thing in the garage if he/she can simply put a plug in a socket? That's not even useful.
        • 4 Years Ago
        I'm afraid your intuition is right.

        There are no easy explanations but all this boils down to simple physics - relation between the magnetic field strength (in the open space) and the distance. In near field the coupling coefficient drops with ~distance^3, so even at a relatively short distance it ends up pretty small (resonant power transfer typically targets coupling coefficients of 1% or less). To compensate for that you need a lot stronger magnetic field, ideally on both sides. A resonant LC circuit is simply just a method to produce such a field (other would be to simply use a beefy power amplifier but that could be less efficient). For example, if you use an LC circuit with Q=100, in each oscillation cycle 100x more energy will flow from L to C and back than it is being delivered to the load (or lost).

        On the plus side - inductive power transfer can be quite efficient (more than EM radiation). The near field mostly stores the energy, only a fraction of it is going to be radiated out as an EM wave and lost. But there are some traps as well - high Q LC circuits loose little power but at this current levels all losses add up to pretty substantial numbers. Also, any lossy resistive (water, metal) or ferromagnetic (steel) materials will loose power in either eddy currents or magnetic histeresis.

        OTOH, inductive power transfer works very well at short distances and/or if some magnetic material is used to carry the magnetic flux around. In both cases coupling coefficient is pretty high (e.g. 0.7~0.99) so most of problems simply disappear and resonant circuits are no longer needed (other than for matching the impedances etc). But since both these methods require either fairly accurate alignment of both coils there is no benefit over simply using a cable.
        • 4 Years Ago
        I never bothered to properly investigate what Tesla patented and started building. There's a cult and conspiracy mania on the internet with anything regarding Tesla. I found it difficult to believe that we wouldn't already be using his techniques if there wasn't some problem with either cost, safety or efficiency. If you know can you explain in layman's terms. Why can't we have wireless recharging that works for cell phones that would work say within a room so it could charge in your pocket? That would not seem to require high power.
      • 4 Years Ago
      This could be used to address the no garage - park on the street problem for apartment dweller EV owners.
        • 4 Years Ago
        If you make those systems so that any vandal vandalizing them gets 400V@50A in their system I think vandalism would stop quite fast. First few get a Darwin Award, rest learn from examples.
        • 4 Years Ago
        Fair point re GE charger and of course this would need to be public infrastructure - however it is more convenient ie. no need to remember to plug in ever if you stop for just a few short minutes you will get a charge (albeit a small charge).

        Less visable charging infrastructure will likely have less vandalism as a result to.
        • 4 Years Ago
        Actually no more than the GE curb side charger. This would still require the community to install the charger. It not like the EV owner is going to dig up the concrete to install this on their own. I would think the curd side charger is probably still less expensive but this eliminates the security concern of having one's valuable cord out for tampering.
      • 4 Years Ago
      We already have cars that can do a complex task like parallel parking a car all by itself. Positioning a car to park over the top of a stop-sign sized device sounds like child's play in comparison.

      Have the car automatically park itself in perfect alignment.

      Then have a simple arm drop from the car to make contact with the pad. How hard is it to design a single articulating arm that automatically retracts itself when you are ready to drive?

      Get and inductive charging system that is 90+% efficient when the pad is in direct contact with the arm, and Lazy America will be happy.
      • 4 Years Ago
      Looks like you trade a bit of efficiency for the convenience of “no cord to plug in”.
        • 4 Years Ago
        Yep, that is the case with all inductive charging. Some systems have as bad as a 50% power loss.. others have 80% at best that i've heard.

        When a lot of our energy is still coming from coal, I think it's pretty irresponsible to run around wasting a ton of energy just for convenience.
      • 4 Years Ago
      isn't wireless charging ever so slightly wastefull?
        • 4 Years Ago
        Don't know what hoops you have to jump through to get there, but the WiTricity site says "In many applications, efficiency can exceed 90%.".
        • 4 Years Ago
        Is it really what people want? Everyday millions of people open/close the door by hand. Some even like it.

        I guess the winning solution would be a rather heavy and fetish looking plug that makes a pleasant "click" sound when inserted into a socket. :-)
        • 4 Years Ago
        Yeah. It seems to me that a better solution might be to build a robotic connector, similar to Better Place's ideas for batteries.
        There would seem to be no reason why an imput point on the underneath of the car could not emit a signal when you push a button, when you are about in the right place and want to charge.
        A robot arm from the ground homing in and making the connection would not seem enormously difficult to engineer.
        Providing it were articulated precise placement of the car should not be needed.
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