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High Efficient wireless power transfer

  1. Apr 18, 2015 #1
    I have been working on the wireless energy transfer recently.Therefore, I am having low efficiency.I have set several coils with different parameters.Could anybody suggest any method to increase the efficiency?I want to transmit high voltage with high efficiency about 50-70W. I have tried with 25 V in source and got max 5 V in receiver coil,the current received was 3 mA when I supplied 1A .The distance is 25 cmAnother question that bothers me is , even though coils reach resonant frequencies they are not transmitting high voltage and current.Why?
     
    Last edited: Apr 18, 2015
  2. jcsd
  3. Apr 18, 2015 #2

    anorlunda

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    How much power are you trying to transmit?

    What have you tried?

    What are your results?

    We can't help you without more detail.
     
  4. Apr 18, 2015 #3
    I have edited the post.please read and give me suggestions.
    Thank you
     
  5. Apr 18, 2015 #4

    anorlunda

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    How much distance between the coils?
     
  6. Apr 18, 2015 #5
    The distance is 25 cm
     
  7. Apr 18, 2015 #6

    anorlunda

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    Have you studied transformer design? Is sounds like you are building a transformer, even if your don't realize it.
     
  8. Apr 18, 2015 #7
    yes I have studied and my goal is also building the step up transformer.what could you suggest?
     
  9. Apr 18, 2015 #8

    anorlunda

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    Good for you. The simplest, most efficient step up I know is an autotransformer. But thst might not meet your other requirements such as wireless or isolation. You should really make up your mind what you're trying to achieve first.


    I suggest searching the threads in this forum. Several threads discuss homemade transformers.

    Perhaps someone else can recommend a textbook or an online forum for this OP.
     
  10. Apr 18, 2015 #9

    anorlunda

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    I am in the middle of Lake Okeechobee at the moment, so my Internet bandwidth is near zero. But a search for "making a transformer" on YouTube brought up some hits. (It also brought up numerous videos on kids transformers toys)
     
  11. Apr 18, 2015 #10
    thank you
     
  12. Apr 18, 2015 #11

    jim hardy

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    you'll find this site interesting

    http://amasci.com/tesla/tmistk.html

     
  13. Apr 19, 2015 #12
    First of all, thank you for the information ,I found it really interesting and generated in me some doubts that I have never thought of.In this experiments, impedance matching was not mentioned.Is the matching of impedance really important?
     
  14. Apr 19, 2015 #13

    jim hardy

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    third paragraph:

    as with any transmission line
     
  15. Apr 19, 2015 #14
    I got the point.But I just want to clarify the reason why we need it.Is it because of, If we have the same impedance, We will have the same resonant frequency? And that is why it is preferable to deploy twin coils to get high efficiency as they resonate in the same frequency?
     
  16. Apr 19, 2015 #15

    jim hardy

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    Resistance will absorb energy. Reactance won't.

    The right amount of resistance will absorb all the incoming energy, any other value will reflect some of it.

    Remember, a resonant circuit appears resistive because XL.and XC are equal and oppposite.
     
  17. Apr 19, 2015 #16
    As the right resistance value provides high absorbing, Could you please tell me how to determine the right resistance value?
     
  18. Apr 19, 2015 #17
    But I thought, resistance dissipates the energy ,how can it adsorb? and what is the benefit of that absorption?
     
  19. Apr 19, 2015 #18

    jim hardy

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    I think you'll have to build one and experiment.

    Your device involves transmission line basics, as mentioned by Beatty in that article.

    here's a very abbreviated introduction.
    http://afni.nimh.nih.gov/sscc/staff/rwcox/ISMRM_2006/Syllabus%202006%20-%203340/files/H_03.pdf [Broken]


    energy enters the resistor as electrical and comes out as thermal.
     
    Last edited by a moderator: May 7, 2017
  20. Apr 20, 2015 #19

    NascentOxygen

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    Are you doing this at mains frequency, 50/60 Hz? Are the coils placed inside one another, or end to end? Are you using an iron or ferrite core?
     
  21. Apr 20, 2015 #20
    I am using resonant frequency not 50/60 HZ.the coils are separated with distance 25 cm. I am not using either iron or ferrite core as my coils are separated.
     
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