9 responses to “Wireless Power Transfer & Transformer Tutorial”

• Kevin January 5th, 2011 at 09:23

  Awesome! Thanks for the tutorial. I’ve started poking around with inductive power with controlled geometries (similar to the cell phone pads). I couldn’t find anything addressing efficiencies and how to overcome losses etc. You wrapped it all up very well.

  I’ll be looking through your other videos too.

  How do you measure inductance? I’ve tried using step response and measuring the ringing frequency with an oscilloscope, but I’m a little wary of the results.

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• firewalker January 5th, 2011 at 22:37

  Very nice tutorial!

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• Mk2 January 6th, 2011 at 01:34

  Wow! That’s a really good stuff. Thanks to VK2ZAY for the tutorial and to you for bringing it to the blog.

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  • Mk2 January 6th, 2011 at 01:59

    For the record: My opinion on viability of high-Q resonant power transfer is same as that of VK2ZAY – nice idea but not robust and unreliable.

    To everything that VK2ZAY said I’ll add a couple of things:

    Eddy currents. What happens if, say, 1% of power is lost in induced currents in a random metal object placed near the transmitter coil? If Q of the system (including load) is higher than 100 then majority of power will now go into that object instead of the load. Hmm..

    All the inductor currents have to be absolutely humongous (this comes from the requirement of transferring high power over a large distance, high-Q resonance is only one method of getting such high currents). Are we sure that extended exposure of our bodies to strong HF AC magnetic field is OK for us? I’d rather plug the power cable to my laptop, if only for peace of mind.

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• George Herold January 6th, 2011 at 14:39

  Dave, that was nice. You can always get a job at a Uni.

  I kept wanting you to draw the field of a dipole. ‘Far away’ from your air coil the field just looks like a dipole. It goes one way here and another there… in the ‘middle’ it’s zero.

  Any way it was fun. My guess is that on the reciever side you want to make the coil resistance about equal to the load resistance. But seriously I think radiative power transfer is mostly a ‘fad’ except for special applications. Perhaps for things in wet environements(sp).

  George H.

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• Michael Thompson January 6th, 2011 at 21:03

  Way above my level of understanding, however there was still great stuff to be gleaned from it and my sparse understanding is now somewhat greater.

  I think I have a slightly better handle on how a homopolar motor works now too.

  73 DE N2NLQ!

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• Shaun Clarke January 7th, 2011 at 19:04

  That went wayyyy over my head…

  Very well spoken and presented though.

  Makes the video I’m working on now look terrible in comparison.

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• Anthony January 7th, 2011 at 23:16

  Telsa Tech I love it.

  http://www.keelynet.com/tesla/00645576.pdf

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• ps3 ylod February 1st, 2012 at 05:09

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  Reply

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