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Autonomous Vehicle Charging, Carbon Footprint, "Small Markets" Survey

Discussion in 'Tesla' started by 22522, Apr 8, 2017.

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Do California Tesla owners care enough about carbon footprint to use efficient AV charging?

  1. No, I like the charging confidence associated with a manual plug. Even if 1% less energy efficient.

    0 vote(s)
    0.0%
  2. No, energy efficiency and convenience are less important than style.

    2 vote(s)
    50.0%
  3. Yes, I could see it as a viable option in California, and China, where energy efficiency matters.

    2 vote(s)
    50.0%
  1. 22522

    22522 Member

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    Do California Tesla owners care enough about carbon footprint to use the self parking summon feature to home charge the vehicle with a better efficiency than what is provided by the hand engaged plug used today?


    The home charging scenario is an ultra efficient inductive charge port under the rear bumper, near where a dual exhaust pipe on an ICE is today, except further under the car and even less visible. The vision is an electric toothbrush like paired "pin in hole" (close coupled) inductive charger with half the carbon footprint of the latest beautiful non-contact inductive chargers. [Pretty sure it can be made more efficient than the plug in charger that is used on Tesla's today, too. The expectation is 'rounds to 97%' efficient from the wall to the battery bus.]
    Charge rate would be 7.2 kW.
    Would not work if you come home to half an inch of black ice, so this would be a regional, warm weather, or covered parking option.
     
  2. deonb

    deonb Supporting Member

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    What is the stuff that you are smoking?

    Just charge the car with some of that and you'll get a 1000 miles out of it.
     
  3. Tam

    Tam Active Member

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    I've been spoiled with 20 kW charging from classic Model S experience, so 7.2 kW does not sound attractive to me.

    I thought inductive (wireless) charging is much less energy efficient than the good old way of manual plug in.

    It sounds like you claim that your proposed toothbrush like system is more efficient.

    More explanations please.
     
  4. 22522

    22522 Member

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    #4 22522, Apr 8, 2017
    Last edited: Apr 8, 2017
    Yes, the toothbrush like way is more efficient, particularly if you carefully modify the standard transformer in an LLC circuit. Over 100 transformer variations were tested in this SAE paper: More Efficient Inductive Electric Vehicle Charger: Using Autonomy to Improve Energy Efficiency

    In the paper, a mature circuit was used as the baseline. The thought here is that if the baseline is improved with the latest technology and the transformer coupling is optimized (the coupling is designed such that the alignment wear surfaces are independent from the active electrically insulating surfaces - so there is room for optimization without compromising safety), energy transfer to the battery bus will be more efficient than the electronics in the cars today. It may turn into a game of leap frog, but the architecture in the paper leaves little of the circuit in the vehicle.

    Depending on the use duty cycle of the different charging methods, a goal would be to reduce the cost of the vehicle while increasing the efficiency of the battery charging that occurs - while bringing the clutter reduction, theft/vandalism reduction and safety benefits of inductive charging.

    Hope this explanation helps.

    (I think it can get to 10kW, (1/2 of 20kW), but have no data to support that claim. So it is 7.2 kW for now as that is a higher probability number).
     
  5. Tam

    Tam Active Member

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    Tesla claims it's 91% charging efficiency for conventional plug-in while the article you cited above says its inductive charging prototype is higher which is 95 to 97% .

    If so, there should be lots of companies come out with this kind of charging energy efficiency.
     
  6. 22522

    22522 Member

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    Yeah, thank you for the reference. I think the onboard is better than that now. Also, there is an integral over voltage and charge rates to make that apples to apples.

    That GE Critical Power team is a descendant of the AT&T Bell Labs Power Laboratory - they did all the power conversion for the telephone network, early Pentium processor point of loads, and now I think they are doing higher voltages for liquid cooled super computers. Even though Apple has done a lot of their recruiting out of there, there is still talent and infrastructure to support product delivery. Their is some IP in there somewhere, too.

    Leap frog will happen in fits and starts.
     
  7. henderrj

    henderrj Member

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    Pretty slick to split the on board charger into two pieces. Still, I don't see the advantage over direct connection. Our thought was that if one is going to go to all this effort why not just make a probe/port connector mechanism (). This would also allow for manually driven or autonomous connectivity. Also, with this split charger inductive means, you still need to have a way to charge it from a straight grid connection. So double the circuitry (or 1.5 times?)

    But either way, or some other way, needs to become a standard for it to do much good.
     
    • Like x 1
  8. 22522

    22522 Member

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    #8 22522, Apr 11, 2017
    Last edited: Apr 11, 2017
    That is really good work. Thanks for posting. And I think each of the perspectives have a lot of merit.

    Here are some adjustments in reverse order

    n) Yeah, there needs to be a standard, or defacto standard. Tesla, or Toyota, or some China based manufacturer could make a defacto standard exist. My experience with standards bodies is that there are people who are participating that are paid to serve the interests of their employers. Defacto standards work better. This approach is about safety and efficiency. I am not sure the luxury market cares enough about efficiency for this.

    n-1) There is actually very little of the split circuit that ends up in the car. About 1/4 of the losses (1% of total power delivered, as we expect 96% efficiency) with no active switching devices - just diodes, capacitors and feedback. It is about 1/6th of the circuit that is in the car by PCB area.

    Let's look at the part that goes in the diffuser of the car. That is an 8 inch caliper for reference. The alignment is planar on the sloped surface to accommodate suspension travel and asymmetries. Using the slope of the diffuser accommodates a lot of suspension ambiguity.

    IMG_4233.JPG

    This next picture shows two Litz wire secondary windings, one shown with the oversized return ferrite core that helps control magnetic fields. These two power trains could be interleaved to provide more than enough capacity for home charging for daily commutes. ~7-10 kW.
    One would provide 3.6 kW.
    IMG_4228.JPG

    The circuitry to smooth the sinusoidal waveform is smaller than a human hand.

    This next picture is for completeness (looking up from the pavement). The flash shows where the primary windings and ferrite center leg goes. This active area is 2 inches wider than it has to be.
    IMG_4232.JPG

    I think there is enough window to manually park with a back up camera with some on screen sighting assist.

    n-2) Yes, there needs to be a conventional onboard charger. Here are some, slightly convoluted, thoughts on that... If super charging and close coupled inductive charging at home are the primary mechanisms for charging, the onboard charger may become vestigial. In the interim, yes.

    n-3) The advantages over direct connection are:

    a) This is designed for multiuser parking spots. Although it can be implemented in a dedicated spot as a docking post, the objective is flat (< 2.5 inches tall) or subsurface in non-controlled environments. It can be driven over by an F-250 with no damage. It is salt and ammonia impervious. Flooding is not a problem and the target service interval is 10 years. The goal would be that a city or condominium could install this without objection, or service, or vandalism for a long time.
    c) Perception of safety. Think about how electric toothbrushes are charged. Do you want a direct connection right beside the sink? There are also benefits of not hooking some utility grounds to the frame of the vehicle during lightning storms.

    The goal is inductive charging benefits, with much better efficiency (half the carbon footprint of the latest technology), much lower "on vehicle" weight, and much lower costs (the baseline power supply we are splitting 5/6ths to 1/6th sells for $300).

    The close coupling does not have the luxury feel, so you really have to care about efficiency and (perception of) safety to implement something like this.

    Note: my employer does consider this as IP, so I have to say patent pending.
     
  9. henderrj

    henderrj Member

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    You have done some really good work!

    We designed the PDP to allow up to 4" off center (as well as off angle, rotation, etc) but found that it was pretty easy to drive, even back, in within an inch if using a projected reticle. You might consider a target (our initial design is my avatar), which should make it quite easy to get within your range.

    Good catch on the supercharging need. I didn't mention level 3 (even level 4, if we end up calling it that). We took the Tesla approach - one connector for all types of charging. I do think that speed of charging will be your greatest challenge. I think you are correct, for overnight it will work 90% of the time.

    I don't see the point on multiuser parking. Any system could be used for that. I really think you have a good viable market for in home charging. It could be added on, like plugless power does, and that might be quite a market. Yours could be greater in that i believe they don't work with refresh S's or X's at all. Add your greater efficiency over the only wireless offering currently available and you might just make a go of this! Good luck!

    ps - sometimes i wish i had a company behind me!
     
  10. 22522

    22522 Member

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    Thanks for the appreciation that only comes from a shared challenge experience.

    There are a couple of things on the multiuser parking. Think back to the self driving Model X video with Stones music. It parked in a Palo Alto or Mountian View street parallel parking space. Street sweepers roll over that space and sweep it periodically.

    If the charger is fine being run over by a street sweeper, flooded and then works perfectly, that Model X could have begin a charge cycle at the end of the video. This charger robustly supports that model.

    Should increase Tesla vehicle demand by 22%.

    I don't see raw contacts living in that environment without a lot of field failures and community concerns.

    This charger robustly supports that charging model and delivers better efficiency than other inductive chargers that are just now coming to market.
     
  11. 22522

    22522 Member

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    Street sweeper plausibility - put a 15 degree ramp around this top view.

    IMG_4234.JPG
    Bottom view that shows build height opportunities to reduce span on cover plates.
    IMG_4237.JPG
     

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