• 33
Daimler B-Class E-Cell Inductive Charging Tests
  • Daimler B-Class E-Cell Inductive Charging Tests
  • Daimler B-Class E-Cell Inductive Charging Tests

  • Daimler B-Class E-Cell Inductive Charging Tests
  • Daimler B-Class E-Cell Inductive Charging Tests

  • Daimler B-Class E-Cell Inductive Charging Tests
  • Daimler B-Class E-Cell Inductive Charging Tests

  • Daimler B-Class E-Cell Inductive Charging Tests
  • Daimler B-Class E-Cell Inductive Charging Tests

  • Daimler B-Class E-Cell Inductive Charging Tests
  • Daimler B-Class E-Cell Inductive Charging Tests

  • Daimler B-Class E-Cell Inductive Charging Tests
  • Daimler B-Class E-Cell Inductive Charging Tests

  • Daimler B-Class E-Cell Inductive Charging Tests
  • Daimler B-Class E-Cell Inductive Charging Tests

  • Daimler B-Class E-Cell Inductive Charging Tests
  • Daimler B-Class E-Cell Inductive Charging Tests

  • Daimler B-Class E-Cell Inductive Charging Tests
  • Daimler B-Class E-Cell Inductive Charging Tests

  • Daimler B-Class E-Cell Inductive Charging Tests
  • Daimler B-Class E-Cell Inductive Charging Tests

  • Daimler B-Class E-Cell Inductive Charging Tests
  • Daimler B-Class E-Cell Inductive Charging Tests

  • Daimler B-Class E-Cell Inductive Charging Tests
  • Daimler B-Class E-Cell Inductive Charging Tests

Whether its WiFi vs. ethernet or cell phones vs. land lines, it's pretty clear that wireless technology is more appealing to people than wired ones. The same will some day be true of plug-in cars, since companies like Rolls-Royce and Toyota, Nissan and Volvo are all trying to get energy from the grid to your car without a wire. Daimler wants to join the club.

That's why Daimler and Conductix-Wampfler are teaming up on inductive charging tests with a Mercedes-Benz B-Class E-Cell Plus. The general idea is that a car can automatically charge up when parked over (or, perhaps, while driving) a special unit in the ground. This eliminates all sorts of potential problems with wired EVs, from vandalism of charging units to people unplugging cars to plain laziness. (Note we said potential; none of these "problems" have been reported in any great numbers, if at all.)

Daimler's tests showed confirmed "the considerable gain of comfort in comparison with cable based charging and that inductive charging is suitable in principle. The potential optimization regarding package, weight and integration in future vehicle model lines is identified and will accordingly be further developed." More information is available after the jump.

Daimler and Conductix-Wampfler conducted the tests with help from the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety. Currently, the efficiency of this wireless technology sits at around 90 percent, which is a bit lower than the performance capability reported by other inductive charging companies. Conductix-Wampfler has been operating wireless charging electric buses Italy since 2003.

*UPDATE: Added Daimler's press release and new photos.
Show full PR text
Field Test on Wireless Charging of Electric Vehicles by Daimler and Conductix-Wampfler

Introduction
The idea sounds as easy as convincing: Instead of „filling up" an electric vehicle by cable the driver parks conveniently above the power source when using contactless inductive charging of the battery. The charging process starts automatically as soon as the car is parked over a charging point. Additional advantages come to the fore especially in public areas: The inductive charging points can be integrated into the ground safe from vandalism.

Currently widespread inductive charging is still a long way off. Yet to test feasibility of such a system Daimler and Conductix-Wampfler have elaborated the basics for wireless charging of electric vehicles in a research project cofunded by the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (Bundesministerium für Umwelt, Naturschutz und Reaktorsicherheit, BMU). Main target of the project "wireless charging" was a safe, automotive grade charging system with maximum efficiency and minimum weight and package.

More Comfort and High Efficiency
Goal of the field test was to evaluate everyday-usability of wireless charging as well as to probe advantages and disadvantages in comparison with charging by plug and cable. As early as a few days into the field test the advantages customer comfort and charging safety by the automated charging process became apparent.

The testing focused on the basic charging process. Efficiency of the system admittedly still doesn´t match charging by cable, but is with 90 percent already very promising and only slightly beneath cable based solutions, if all components from socket to battery are taken into account.

There was an evaluation of the first "driving-experiences" with study participants who had to "drive onto the optimum charging position". After two or three exercise runs this could be well achieved supported by parking assistance functions. The system tolerates smaller deviations within the range of a few centimeters without noteworthy loss of charging efficiency or transferable power. Also, the system showed already good results regarding electro magnetic compatibility. It is the task of future engineering work to optimize this as well as to improve efficiency and to develop solutions for a series application.

Technology and Vehicle
The protototypes built within the project on the basis of the B-Class E-CELL with range extender are equipped with an electronic rectifier and a collector coil integrated into the underbody cover. Main components on the infrastructure side are the supplying electronic and the charging coil, which was realized in two variants – as an above ground and beneath ground coil.

Besides the wireless energy transfer other functional aspects are the wireless communication between infrastructure and car, the driver assistance function "driving onto the position above the charging coil", the automatic start of the charging process and the vehicle identification. In the area between the coils an object detection avoids risks by warmed metal items.

Detailed scientific studies generated the foundation for the first layout of the inductive transfer components with automotive specific requirements and their optimization regarding package and weight. Comprehensive system simulations served to validate the designs.

Conductix-Wampfler has developed all components of the system and could rely during the process on comprehensive experience with inductice power transfer in manufacturing automation as well as on know-how from the wireless charging of electric busses in Genoa and Turin. These are in operation since 2003.

Daimler has defined the functions of the charging system on the car´s side and realized the assistance system for driver support. The system was integrated into two vehicles with range extender, nameplate Mercedes-Benz B-Class E-CELL Plus. The coil integration within the underbody cover of the cars was designed and supplied by Röchling Automotive.

After the prototype vehicles had been built the complete system was mechanically and electrically integrated and taken into operation as a whole. Two inductive charging stations are in the field at the Daimler-Engineering-Location Böblingen-Hulb and are intensively used for the everyday-tests.

Résumé and Outlook
First conclusions confirm the considerable gain of comfort in comparison with cable based charging and that inductive charging is suitable in principle. The potential optimization regarding package, weight and integration in future vehicle model lines is identified and will accordingly be further developed.

At the same time an evaluation is done on new common projects with potential inductive charging applications in small commercial vehicles and busses. The results of the current tests are important to national and international standardization activities – with the aim to guarantee interoperability of inductive charging systems of different suppliers and vehicle manufacturers.

Short Profile Conductix-Wampfler
Conductix-Wampfler is the world's leading supplier of mobile energy supply and data transmission systems. With own companies and several partners Conductix-Wampfler is present in nearly all relevant countries. With about 1.000 employees across the globe, the group generated sales of over € 177 million in fiscal 2010.

Electric car unplugged – Daimler to test inductive charging in everyday trial

Berlin, Dec 07, 2011

Project "Effizienzhaus-Plus mit Elektromobilität" combines zero-emission living and driving in Berlin

Daimler is first automotive partner to provide three electric vehicles for the project sponsored by the Federal Ministry of Transport, Building and Urban Affairs

Berlin – Charging electric cars without an electric cable – how does that work? Daimler AG is about to test inductive charging for the first time on a vehicle in everyday use in the form of a technically modified Mercedes-Benz A-Class E-CELL. With the inductive charging principle, an electric car fitted with a special charging coil merely has to be positioned over a charging coil in the ground to start the charging process fully automatically, with no need for cable contact. "We are keen to find out how the inductive charging process proves in daily use," says Herbert Kohler, head of e-drive & future mobility in the Research and Advance Development department at Daimler AG. "We have already demonstrated the essential feasibility of the technology. The experience in day-to-day use will now provide important pointers for the further course of development. A number of technical and financial issues also need to be resolved before we can really assess the marketability of this technology."

The electric car will be deployed from March 2012 in the project "Effizienzhaus-Plus mit Elektromobilität", which was inaugurated in Berlin today by Federal Chancellor Dr. Angela Merkel and Dr. Peter Ramsauer, Member of the Bundestag and Federal Minister of Transport, Building and Urban Affairs. Through the application of cutting-edge technologies, the energy-efficient house in this pilot project is intended to generate more electricity than it consumes. This surplus electricity can be used to recharge battery-powered electric vehicles, for example – the home as a personal filling station. The entire building has been designed along energy-efficient lines, seamlessly incorporating the area of electric mobility. Both the inductive and the cable-based charging devices are harmonically integrated in the house's architecture, for example. A family of four will live at the house on an experimental basis for 15 months, beginning in March 2012. During their stay at the house they will use various electric vehicles to explore and demonstrate how a new generation of buildings and electric mobility interact in daily life. Apart from the Mercedes-Benz A-Class E-CELL with inductive charging option, Daimler AG will be providing the "Effizienzhaus-Plus mit Elektromobilität" project from the start in March 2012 with two other battery-powered electric vehicles for around three months: the second-generation smart fortwo electric drive and the smart ebike. The family will thus have a broad spectrum of battery-powered local emission-free electric vehicles from Daimler at its disposal to cover the most diverse uses. From the two-seater tailored perfectly to urban needs through the 5-seater family car to the electric bike which opens the door to electric mobility without any need for a driving licence. Daimler will also attend to installation of the necessary charging infrastructure at the house, providing a wallbox for conductive charging with a cable and a charging coil for inductive charging in the carport. Alternatively, the family will also be able to charge all the vehicles at public charging stations or by plugging them into a standard domestic power outlet.

The project "Effizienzhaus-Plus mit Elektromobilität" will show that sustainable living and driving is possible without compromising on one's quality of life. Scientific evaluation of the data on usage of the vehicle which are collected in the course of the project may additionally provide important insights into customers' wishes – and show how electric cars can become yet more sustainable and at the same time more comfortable and convenient in the future.

Charging without a cable

In addition to charging with a cable, the Mercedes-Benz A-Class E-CELL to be deployed in this project can also be charged inductively. This involves non-contact transmission of the charging current by means of an electromagnetic field. For this purpose, both the vehicle and the parking space at the energy-efficient house are fitted with corresponding coils. A special display system helps the driver to manoeuvre the vehicle into the ideal position over the charging coil.

In cooperation with Conductix-Wampfler and Röchling Automotive KG, Daimler has already developed a prototype version of this technology and demonstrated its functional effectiveness in a project sponsored by the Federal Ministry of the Environment. The technology's suitability for everyday use is now to be sounded out thoroughly in the course of the practical trial.

A perfect match: energy-efficient house and electric vehicle in coordinated design

In order to highlight the close functional relationship between house and vehicle, a special edition has been developed for the "Effizienzhaus-Plus" project in close consultation between the Mercedes-Benz Design department and "Effizienzhaus-Plus" architect Prof. Werner Sobek. In keeping with the design and colour concept for the house, white and natural tones are predominant in the exterior and interior design of the Mercedes-Benz A-Class E-CELL and the second-generation smart fortwo electric drive. A specially developed pearl coat in platinum white metallic lends the vehicles a strong presence and reflects heat, thereby helping to keep the interior cool. The combined use of natural textiles such as wool, linen and nappa leather provides for an attractive contrast.

The coordinated design means that the family will feel totally at home in the cars, thus communicating the concept of integrated sustainable home living and motoring on a visual and an emotional level.

Further information about the project is available online: www.bmvbs.de/effizienzhausplus


I'm reporting this comment as:

Reported comments and users are reviewed by Autoblog staff 24 hours a day, seven days a week to determine whether they violate Community Guideline. Accounts are penalized for Community Guidelines violations and serious or repeated violations can lead to account termination.


    • 1 Second Ago
  • 33 Comments
      Spec
      • 3 Years Ago
      Well if everyone is all gung-ho about these wireless charging systems then they really should start addressing the real issue . . . creating industry standards so any EV can use any wireless charging system. And billing systems for charging the EV owner. It is costs and politics that are the issue, not technology with wireless charging.
        JakeY
        • 3 Years Ago
        @Spec
        That's what I mentioned too in other threads. With all the different wireless systems being developed, there better be standards very soon (I heard SAE is working on one) or it'll be a huge mess (even worse than the connector situation since adapters won't work here).
        Joeviocoe
        • 3 Years Ago
        @Spec
        Wireless standards would be nice.. but much more difficult to implement than connectors. The size and placement of the car's inductive charging coil(s) makes it a very restrictive proposition for automakers. A charging port such as Mennekes, Chademo, or SAE is small enough to be placed any where convenient and not in the way of other vehicle components. But it takes very specific engineering to make sure that the vehicle's coil(s) are large enough to get over 90% efficiency while not being Exactly over the ground coil(s), and at the same time not being too close to large section of metals that would affect the EM field of the induction. Also, how close can the battery get without affecting either the induction charging or the battery itself? A hastily done standard could make engineering a good EV more difficult. Let's first prove that an EV can be made with 24 kwh or greater Li-Ion battery under the cabin, and still have plenty of room for a 90% or greater efficiency inductive charger. Then we can start talking about industry wide standards. The conductive charging standard(s) did not come until MANY EVs had working non-standard charging methods.
          Spec
          • 3 Years Ago
          @Joeviocoe
          How about "Let's prove that the EV market is a viable business" before we start adding more expensive bells & whistles. Then again, maybe the fact that people push forward with wireless charge systems mean that they take EVs as a real viable industry for granted.
          Joeviocoe
          • 3 Years Ago
          @Joeviocoe
          Spec, I don't think we should wait for those bells and whistles at all. I don't know why I came across that way. I just think we should wait to "standardize" those features across the whole industry.
      • 3 Years Ago
      Inductive charging has some logistical and use advantage, but I’m skeptical it will actually be accepted in the EU. This is a regulatory environment in which household energy use is constantly being analyzed for improvement, where the push for “renewable” sources will stretch the REAL (not nameplate) generating capacity, and where the general habit of conservation is very strong. (If you’re a Yank who neglects the “one up, two down” elevator rule in a French office building, you’ll find this out quickly.) BTW, I’m not demeaning the personal conviction toward conservation --- I admire it. So how is it that the EU regulator will look at a 10% charge power throwaway for the sake of convenience and sign off on that? Say a Fluence consumes about 150w/km (which for the sake of discussion is close enough). Fabrice, let’s call him --- a typical driver --- will put 40-50km a day in his commute from the suburbs of Toulouse to his job at EADS, including dropping off the kids at their school and running odd errands. He’ll need to put 7kW-hr back in the battery at night. No problem; with a charging efficiency in the range of 95% or so (optimistic), he’ll consume about 7.5kW-hr. Unless he’s using an inductive unit, which will burn an additional 600W-hr (I’m assuming better than 90% for the inductive connection). So Fabrice and nine other residents of the quiet little Rue du Banlieusard will be throwing away almost enough energy to charge another Fluence, all because they were too lazy to plug in. Mon dieu --- do you honestly think the Bureaucrats of La Belle France will sign up to this, in a place where an errant 600W-hr per day will cause an EU regulator to yank a refrigerator off the market? It’s even dumber for rapid charging, BTW. Not in the cards, je pense…
        Hans
        • 3 Years Ago
        I beg to differentiate. At home you'd use a cable - of course. If only it were to avoid the electric smog (whether it's a myth or a fact - some people care) and the waste of energy. In public areas though (parking at the mall, at work, on the street) the cable is not just a nuisance. The whole electrical installation can be vandalised, takes precious space, takes a permit to even put one up. Embed the whole thing into the road, like an induction cooker. Clean, safe, robust.
          JakeY
          • 3 Years Ago
          @Hans
          "The whole electrical installation can be vandalised, takes precious space, takes a permit to even put one up. Embed the whole thing into the road, like an induction cooker. Clean, safe, robust." I think that is a bit too ideal of a look. 1) Vandalism: If the cord is locked to the car while charging, what kind of vandalism can really be done (besides from cutting the cord, which most people won't do for fear of shock)? The worst is someone unplugging the socket if it's not lockable. There is no evidence there is a big concern for this at this point. And it's not like an inductive system is immune to vandalism (it still needs a box to pay for and manage the charge and vandals can still put things between the charging pads to screw with you). 2) "takes precious space": Again, in an inductive charging system, you still need a box to pay for and manage the charge (although it may be integrated into one per block; not that a conductive system can't do the same thing - except for the cable). 3) "takes a permit to even put one up" And an inductive system doesn't? The main convenience is saving you a couple of seconds from plugging in and saving the "clutter" (visual and physical) of a cable.
        Spec
        • 3 Years Ago
        Well I agree with that sentiment. Is it really worth a 10% hit to save the 7 seconds it takes to plug in?
          EZEE
          • 3 Years Ago
          @Spec
          If your marriage is worth it it damn sure is! I am in a jolly mood this morning.
      DaveMart
      • 3 Years Ago
      I'd use a cord at home, but getting rid of the clutter of street furniture needed for corded charging away from home make wireless far more practical there and worth the energy penalty. I'd like to see the post that Nissan retain done away with too. Some sort of electronic handshake should be able to do the job without needing it. Perhaps 90% of charging is likely to be done at home, so assuming a 10% efficiency penalty for wireless total losses would only be of the order of 1%.
        JakeY
        • 3 Years Ago
        @DaveMart
        "Perhaps 90% of charging is likely to be done at home, so assuming a 10% efficiency penalty for wireless total losses would only be of the order of 1%." That's incorrect. You aren't losing 10% out of the 10% normal charging losses (what you did in your calculation). So your math (10% wireless transmission loss * 10% charger loss = 1% overall loss) is incorrect. The math should be 90% transmission efficiency * 90% charging efficiency = 81% overall efficiency. For example: Let's assume 90% conventional charging efficiency. So for every 100kWh from the mains, you see 90kWh stored in the battery after charging is done. If air gap losses is 10%, that means after you go through the air gap, you see 90kWh left (100kWh * 90%). Then you see the additional 10% loss after that from normal charging, so 81kWh is left (90kWh * 90%).
        Letstakeawalk
        • 3 Years Ago
        @DaveMart
        I agree, the biggest benefit will be in the public space. Not having corded charging stations will make them much more visually acceptable in a variety of urban environments.
        DaveMart
        • 3 Years Ago
        @DaveMart
        JakeY: You are missing the argument I was making. I was assuming using wired charging at home, so that if your argument is correct that that is the most efficient way of charging, and I am assuming in the argument in this post is it, you are at 100% or IOW the 'best possible' efficiency, whatever that is in terms of actual efficiency, be it 90% or 80% or whatever. If you then do just 10% of your charging away from home, then I am assuming that you have an energy penalty of 10% over and above whatever the losses are on wired charging. So I come out with an overall loss of 1% of the best possible efficiency we could hit by using all wired charging.
      DaveMart
      • 3 Years Ago
      I've just come across Ine's invaluable comment in another thread, which I will quote here in its entirety: '"But an EVSE has additional system losses. Once the AC reaches your vehicle, it has to be converted to higher voltage DC by the charger in your car. This requires a transformer (or equivalent switching circuit) to get to that voltage and rectification. What is a transformer? Two coils of wire right next to each other that create an EM field that passes from one to the other. What is an inductive charger? two coils of wire that create a focused EM field that is transferred from one to the other. The big difference is the focused EM field is travelling a further distance with an inductive charger vs. an unfocused EM field travelling a very short distance in a transformer. Basically, you greatly simplify the power supply and replace transformer losses. Think about the Sonicare toothbrush example... there is no powersupply for charging (that black box at the end of your cell phone charger). Much of the losses associated with the powersupply in a conventional charger offset the inductive charger losses. So no, EVSE charger losses are not on top of that.' This means that there are further savings apart from losses in the cord. It should be noted that Utah University claim 98% efficiency: http://www.ksl.com/?nid=148&sid=18116082&autostart=y Presumably they are using Resonant Inductive Coupling, which is described here for those who can follow it, but is way above my pay grade: http://en.wikipedia.org/wiki/Resonant_inductive_coupling
        lne937s
        • 3 Years Ago
        @DaveMart
        BTW, This diagram from the 2009 prototype shows further detail. It clearly shows the coil going to the rectifier (not charger) to the battery. http://www.nissan-global.com/EN/TECHNOLOGY/OVERVIEW/charging.html By taking care of the voltage change outside of the car, you gain eficiencies. In addition, making more of the system stationary means you can optimize efficiency without size and bulk tradeoffs associated with carrying it around. Now, nobody is claiming this has superior efficiency . And, as gaps vary, the numbers cited by different manufacturers are not always comparable. However, Nissan and others have gotten the chargers to the point where the efficiency is pretty close... enough to justify the convenience.
          lne937s
          • 3 Years Ago
          @lne937s
          I'll have to look around when I get a chance. There was some discussion in October, when the Nissan system was announced, and some more in 2009, which is probably out of date. However, I don't have the links at hand.
          DaveMart
          • 3 Years Ago
          @lne937s
          I have found it: http://www.nissan-global.com/COMMON/PDF/TECHNOLOGIES/te_111013-01-06-e.pdf
          JakeY
          • 3 Years Ago
          @lne937s
          @DaveMart: "a near unity power factor" http://en.wikipedia.org/wiki/Power_factor That refers to loads that have energy storage, capacitors or inductors, (which would generally a power factor under 1.0) rather than being purely resistive (which would have a "unity" or 1.0 power factor). The issue with loads with energy storage (non-unity power factor) is there is power being transferred that isn't directly used by the load. Rather, it is stored by the load and then later transferred back to the grid. This causes additional current to flow which isn't actually being used to do any useful work, which is wasteful (since it increase resistive losses through the power line). "BTW I was quite wrong that it is limited to low power. The system powering buses in Italy is rated at 60kw." A resonance based system can operate at higher power because of the coupling mentioned in the previous links (the standard induction based system in Nissan's implementation doesn't have the same coupling, which is why it is limited in power). The coil to coil efficiency can be 98% (which reduces the amount of waste heat and interference generated by the coils), but there are extra losses from the power supply to the transmitting coil (because you need extra switching on the transmitter side to get to that resonant frequency). And a bus-sized system may have large coils that are not practical in a car.
          DaveMart
          • 3 Years Ago
          @lne937s
          JakeY Many thanks. It seems from the above then that the efficiency compared to wired charging is underestimated at any rate at the grid level, so that although the customer may not see it on their bill the actual amount of energy the grid would have to supply may be very close for inductive charging and wired, or even have some small advantage to inductive. Have I got that about right, and does this consideration alter your own evaluation? On the 98% efficiency coil to coil of magnetic resonant, we now have a figure which makes sense of Utah University's claims. Do you have any ball-park estimates for the losses in the extra switching?
          DaveMart
          • 3 Years Ago
          @lne937s
          JakeY: Just to be clear I am not an engineer and don't fancy myself as being able to constructively critique the various designs. The best I can do is collate and present other people's claims and presentations. It is not unusual in a new technology, or at any rate one only now hitting the big time, for different approaches to present different figures and efficiencies, nor is it always clear that the ones they are using are comparable.
          JakeY
          • 3 Years Ago
          @lne937s
          "It clearly shows the coil going to the rectifier (not charger) to the battery." That doesn't necessarily mean that they do any step up with the transformer. Some EV chargers don't use transformers, but rather use diodes to do voltage multiplication (then they can use buck converters to do the rest). http://en.wikipedia.org/wiki/Rectifier#Voltage-multipling_rectifiers "By taking care of the voltage change outside of the car, you gain eficiencies" I dispute that. There is no way a transformer with such a huge air gap and alignment issues will be higher in efficiency than a transformer with virtually no air gap and possibly a core (plus you also can use other techniques to boost the voltage if that turns out more efficient). This is making it sound like there are efficiency gains over a conductive system, which I'm pretty sure no wireless system will claim. However, it might be more efficient than going through a second transformer (depending if the doing the step up has any effect over transmission efficiency), if that is what you are saying. "Now, nobody is claiming this has superior efficiency" But people are claiming it is very close to conductive efficiency (see DaveMart's long comment in the previous article: http://green.autoblog.com/2011/12/04/future-nissan-leaf-could-be-cheaper-may-have-more-range-wil/#aol-comments) to the point of there being insignificant differences (quoting ~80% overall charging efficiency in the Tesla and the Leaf). I'm arguing the figures are not measuring the same things. Even if you assume this replaces the transformer (which after doing some research, doesn't seem to make much efficiency difference, less than 5%), that leaves out the rectifier and battery losses. Actual verification of the efficiency difference will require waiting until an inductive charging system is offered for sale. Anyways, even at 90% efficiency (I'm assuming air gap here), I would agree that probably is "good enough" to justify the convenience in public charging. I still question it in other situations where a conductive system works perfectly fine (automakers are trying to squeeze every last drop of efficiency out of cars, and it seems wasteful to just throw it away). I would rather wait for resonance based wireless charging, as that seems to be much more efficient (although more complicated: it probably won't work with the typical 60Hz input from mains power so there needs to be more electronics). And regardless which technology prevails, there needs to be standards (coil size/number, distance, tolerances, location of the pads, input and output voltages, etc) to ensure all systems are compatible.
          DaveMart
          • 3 Years Ago
          @lne937s
          Ine, Have you a link to the pdf referred to on system losses? I haven't spotted it in the discussion about it.
          DaveMart
          • 3 Years Ago
          @lne937s
          Here is another factor which I am unable to make head or tail of, but others might be able to - a near unity power factor: 'UK-based induction charging system developer HaloIPT claims that its system places minimal strain on existing grids because it offers ‘near unity power factor’. In doing so, it reduces power loss so that utilities can supply power to it without radically overhauling their distribution infrastructure. Managing Director Anthony Thompson explains: “We use power factor correction with capacitors and filtering to control harmonics. The significance of power factor lies in the fact that utility companies supply customers with volt-amperes, but bill them for watts. Power factors below unity require a utility to generate more than the minimum volt-amperes necessary to supply the real power (watts), which increases generation and transmission costs.” If the load power factor was 0.7, for instance, the apparent power would be 1.4 times the real power used by the load. Line current in the circuit would also be 1.4 times the current required at 1.0 power factor. The losses in the circuit would therefore be doubled (since they are proportional to the square of the current). “Alternatively all components of the system such as generators, conductors, transformers, and switchgear would be increased in size (and cost) to carry the extra current”, Thompson concludes. One of HaloIPT’s corporate partners, the consulting engineer Arup, knows a thing or two about infrastructure, and has also been significantly involved in automotive engineering. Meanwhile, HaloIPT’s installation partner in the UK, Chargemaster, evolved from the traffic information supplier Trafficmaster’s 25 years experience within telematics.' http://analysis.evupdate.com/industry-insight/inductive-charging-part-2-challenges-wireless-pioneers And there is a rather nice illustration of the reduction is the clutter of street furniture possible here: http://www.oasys-software.com/dyna/en/events/users_jan-11/HaloIPT_Matt-Cooper.pdf BTW I was quite wrong that it is limited to low power. The system powering buses in Italy is rated at 60kw.
        DaveMart
        • 3 Years Ago
        @DaveMart
        It seems total losses may be, emphasis may be, no greater than using a cord, in which case it makes sense to use it at home too and not bother about a cord. An exception may be for very fast charging, as 6.6kw seems to be about it.
        EZEE
        • 3 Years Ago
        @DaveMart
        Electrical Engineer Here... What he just said...
          lne937s
          • 3 Years Ago
          @EZEE
          EZEE- Glad what I said made sense. I am not an electrical engineer and sometimes do not use the technically correct terminology. Most of my experience with electronics came from building amplifiers and speakers as a hobby.
          JakeY
          • 3 Years Ago
          @EZEE
          @DaveMart This wiki article is going to be insightful: http://en.wikipedia.org/wiki/Resonant_inductive_coupling
          DaveMart
          • 3 Years Ago
          @EZEE
          EZEE Electrical Engineer: How about pulling your finger out then and going through some of the stuff I can't understand such as Resonant Inductive Coupling and giving us the low-down of what you reckon the achievable efficiencies are compared to wired? :-) I'm not even sure what the 98% efficiency claim of Utah represents, as of course there are battery charging losses.
          DaveMart
          • 3 Years Ago
          @EZEE
          Jake: Thanks for the link. It is somewhat clearer, but of course that does not mean that I can follow the mathematics. On the same site Witricity say that efficiencies of over 95% are possible, although it is not clear whether that is achievable in a car application.
          JakeY
          • 3 Years Ago
          @EZEE
          @Jakey whoops, I didn't realize you already had that wiki link. The wiki seemed pretty clear to me, but perhaps you need a bit of EE background to understand it fully. Perhaps this link provides a easier explanation: http://www.witricity.com/pages/technology.html
        Dave
        • 3 Years Ago
        @DaveMart
        The transformer does not convert AC current to DC current. The rectifier does. http://en.wikipedia.org/wiki/Rectifier
          lne937s
          • 3 Years Ago
          @Dave
          Exactly--I thought that was clear. A transformer changes AC voltage before the rectifier. This is where the AC induction coils come in. EV batteries do not charge at 120v or 240v, the charger (essentially a transformer and a rectifier) increases the voltage and converts to DC. The induction coils eliminate the transformer (or equivalent switching circuit) from the circuit that charges the battery in the car. Rectifier losses are a fairly small portion of the energy losses in a power supply.
    • Load More Comments