Wireless power transfer - DIY Experiments #10 - Resonant inductive coupling
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- เผยแพร่เมื่อ 12 เม.ย. 2020
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• How it works?
The electronic circuit transforms efficiently the direct current from the power supply into a sine current having a high frequency of near 100 kHz.
We need the current in the emitter to vary constantly in order to get a varying magnetic flux. Then, a varying magnetic flux can generate electricity remotely in the receiver coil. This is induction.
To better visualize this invisible energy vector, it’s possible to make an analogy with light which is an electromagnetic wave. It's possible to convert electricity into light, then the light can be converted back into electricity with a solar cell. The overall efficiency is lower, but it works.
The fact to use induction to transfer power is not new, transformers works the same way, there are using a solid core to lead the magnetic flux from the primary to the secondary coil. It’s essential to lead the magnetic flux because if a fraction of the flux doesn’t reach the secondary coil, the coils coupling is reduced and so is the efficiency.
With wireless power transmission, the aim is precisely that nothing is between the two parts. Consequently, it’s impossible to retrieve entirely the magnetic flux, especially when the distance is higher than the coils size. We are forced to send out more power that the useful load power.
Luckily, there is a way to partially overcome this problem. We use resonance. The resonance here means the fact that a coil and a capacitor can exchange energy each other.
In short, if a capacitor discharges in a coil, the coil produces a magnetic field. Once the capacitor is fully discharged, the magnetic field vanishes, so it varies and the coil produces back a reverse voltage in the capacitor, and so on.
This resonance can only occur at a precise frequency which depends on the coil inductance L and capacitor capacity C. It’s called an LC circuit.
So, great, the inductance and the capacitor can exchange energy, but why does it allows us to retrieve more energy?
The receiving coil produces a voltage according to the varying magnetic flux, but the coil has a drawback, as any coil, is has an inductance which narrows the current.
The inductance of the coil doesn’t reduce the current by loosing energy like a resistor, it rather delays the current variation by storing and releasing energy. The higher the frequency, the more the current is impeded. That’s why the generic link between voltage and current is called the impedance.
The fact is, when in an LC circuit is tuned to its resonance frequency, the coil and the capacitor impedances cancel each other. This way, we are completely removing the coil limitation and the resonance allows us to retrieve more energy. The resonance also increases the output voltage so it’s easier to supply loads.
Finally, the resonance forces the receiving coil to retrieve a higher fraction of the magnetic flux. The coupling between the emitting and receiving coils is increased, so is the flux density between the two coils.
The difference with or without the resonance isn’t negligible, for instance, the lamp’s filament turns from barely red to almost its melting point.
To get the resonance, as you understood, we simply need to add a capacitor in parallel with the coil. But there is one condition to follow, the resonance frequency should be as close as possible to the emitter frequency, in our case near 100 kHz.
We have to adjust precisely the capacity with one or several capacitors according to the coil inductance and the frequency. The simple fact to space out the two spins of the coil changes enough it’s inductance to detune the circuit.
About the emitter electronics, it’s a zero-volt switching circuit able to maintain a resonance between the emitter coil and its capacitor. It’s an efficient way to get a high frequency sine current in the emitter coil.
About the overall efficiency, it’s rather weak, but in short distances with identical coils we reached more than 80%.
The main issue it that the retrieved power decreases quickly depending on the transmission distance.
As a workaround, we use a different geometry in our magic carpet, the emitting and receiving coils are in the same plane. When we move away from one edge, we get closer to another.
This way, the power decreases slowly with the transmission distance and it’s easier to maintain a constant power requirement on several axes.
The magic carpet requires 2A with 24V when there are no supplied devices.
The current can reach 3A when all devices are inside. Only this over-consumption corresponds to the energy consumed by the devices. Thus, the overall efficiency is better when there are many devices.
Thanks for reading, ask us any question :) - วิทยาศาสตร์และเทคโนโลยี
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My son has a project for 11th grade. We were looking for something for his project and found your video. This is really amazing. The idea for magic carpet is great. Your demos are clear and with good description. Thank you for this upload. Great work. Keep it up.
did u guys use this as inspiration for the project?? let us know what he chose, n keep us updated on his results!! sounds fun 👍
Thank you for your reply. He had two objective, namely 1. Wireless power transmission, and 2. Adding load without affecting the transmitter power. So he submitted for the first part, and he got an A+; he did mention you channel and source. However, we modified the circuit a bit with 35KHz frequency and played with several capacitors and different inductors for correct resonance frequencies for Tx and Rx. Worked great. The whole class and school enjoyed it. Thank you.
hi. can you please list all the parts that yo used in the project
You are an amazing dad!!
Wow! Really amazing! Well done! I did not think that what you have achieved is possible, and the high efficiency (80% or more) obtained when your devices were closer excites me. Thank you for making and posting this video.
Wow. You are da GOAT. You inspire me to make one of my own and learn more in the process.
I am quite familiar with wireless power transfer and the range is impressive. nice work!
Absolutely fantastic !!!
The idea of placing the conductor on the edge of the room and making complete room a wireless electricity transmitter is so futuristic.
I am totally amazed!!!
He is a junior Tesla!!! I agree with you his idea for whole room transmission is genius. He is truly opening the door to wireless power for every day life around the house.
you are simply awesome. That Magic carpet idea is geenioussss!!!!! I really loved it. Very very innovative idea. I've learnt so many things from this video. Thanks for making this video.
Awesome video! I had a project idea about a table with a coil below the top to power stuff but got discouraged when I did some math. Given certain parameters, I would have needed an insane amount of flux to just get 5 V on the receiver coil (more flux than industrial-grade stuff). This video proves to me that either something is wrong with my math, or the use of tuning components is a much bigger deal than I thought it would be.
Mr Sandman. Enjoyed the video and your English is excellent.
Brilliant idea one plug give all electric devices wireless work! Nice work!
Well done. Good demonstration of impedance and q factor. Nice visuals.
Ca fait plaisir de vous revoir !
can you tell me how I find the mosfets?
I love your channel!
Mr Sandman. The Entertainer.. great idea using the rug
You're back!
Very very ,nice , thank you very much , i like your work, that entire room wireless idea is very nice ,love you😘
You are doing good job, please keep it up
Congratulations best I seen yet. The baseboard wiring antenna is a great idea too. I have been doing experiments myself but your work has left an impression on me. I am so happy to see a young person as yourself producing such amazing results for wireless energy ideas. Don't give up this dream it is the future. Embrace your innovations and you will go far. You have already found some ways to overcome distances of transmitting energy and exceeded a lot of others that I have seen so far. You baseboard transmitter antennas are especially creative. I have been using Tesla exiciters and plasma balls as transmitters and been working on resonant antennas to improve distances unfortunately these Tesla transmitters are very noisy radio frequencies so making things practical for every day use is the greatest obstacle other than distance from the transmission overcoming them will insure your success. Amazing video! Congratulations again and thank you for sharing.
Great comment! How’s it going with your experiment?
Very good explanation 👍🏻thankyou. Subbed
This was awesome!
Amazing project
Could you assist with the electronic diaram and explain why those components are used
Thanks
I heard that. The entertainer by Scott joplin. Also Mr. Sandman. Awesome video.
love that topic❤❤
Hi, great video!!! What kind of transformer did you use in the emitting coil? I mean the ones that you guys screwed onto the circuit board.
Hi, great work!! I'm trying to understund how you adjust the voltage in your devices. Or whats the relation between the field in your transmiter coil and your reciver coil. I want to make a similar proyect but i get losst in this point. Thank you all!!
Nice project
Nice video
Great video!!! Pls how do you determine the capacitance of the capacitor to be used
It’s wonderful.
Will Appreciate if you could PLEASE show the CIRCUIT DIAGRAM.
Thanks. 👍🏻
Hello. Thank you for video and you are can make an solar accumulator charger?
hey, loved the tutorial! could you please list the parts that you used needed it for a school project would be great help....
Alors comme ça on se lance dans le TH-cam international !
C'est cool d'avoir une nouvelle vidéo, même si c'est du recyclage 😉
Depuis 5 ans ouais ^^
Il y a quand même des dizaines d'heures d'améliorations, infographies nouvelles, explications plus poussées, etc. :)
Great video. Your explanation of how you increase transmission distance is excellent. 🎉I would like to build a magic carpet. Can you send me the circuit diagram and a component list that will allow me to make a carpet that is 10 x 11 feet? Also need to know how many windings are in the rug coil and the wire gage and type. Last question. Should the rug coil be insulated wire for safety?
How do you choose magnetic material for the toroidal coils ?
Have you a way to estimate the volume /size of the toroidal core ?
Amazing video, its a shame you dont make more videos.
hi. i love this experiment and was hopping to try it at home. i was wondering if you can list the different parts you need to make the circuit.
did you get the listt?... please share if possible
Can you show how to make it from strach
can you tell me how I find the mosfets?
SHOCKING get it you got the POWER
It works just as transformer without ferromagnetic core. Its very cool but, outer power is very low in comparison with input power. But really cool:)
that was nice
5:53 Scott Joplin, the entertainer
You have almost reached which is merely in research level 🔥, induction over long distances,,, if perfected it will surely be a groundbreaking tech,, and ur description is awesome 🔥
Amazing 👏 How about creating an smd version of your project using batteries. I am working on such a design.
So did you fry any of the not-intended-to-receive-power-wirelessly electronics in your room?
You r really awesome man...i would like to know if i cover my entire room...will it effect other electronic devices like hard drives or motherboard of my pc
If they arent near to the wire ,nor the reciver coil then it should be fine ,unless if u put too much power in it .. the whole thins is about to extend electromagnetism with resonance coupling ..
Thank you for showing. Can you post the schematic of the power's source or the schematic of the transmitter's source? or can I go to some site to see it?
It appears at the end of the video
Kannst du mir sagen, wie ich die Mosfets finde ?
I'm liking and subscribing. Dude, I wanna know how to make this to deliver 5 volts at 3 amps.
did u use dc power source or ac power source?
What is the full name of the diod that you used in sending circuit?
This "wireless" power transfer is called so because the amount of coiled wire in it is three times bigger than in wired power transmission, or are there other reasons for it?
#2... Kevin Macleod, If I had a chicken
Would this work if the power supply was an 2kw wind or hidro turbine?
Do you have any ppt & documentation Wireless power transfer resonance inductive cupling
You are so innovative sir the magic carpet blew my mind
You are awesome
Mosfet numbers are different, which one to use?
The lowest RDSon!
Hi can I get the cercit for the primary and secondary
I would like to take this to the next level. Interested in working with me?
hi im impressed with your device i would like to make a similar one could i have a schematic please i would be very grateful thank you
can you use this to charge a battery?
what is the current that he use in the circuit please AC or DC ?
Which transistor you are using
So can you try the same thing but with rodin coils, maybe you will get wider range :D
Is there a way to build a miniature wireless charger, install it on a RC car and pass close to a cellphone and charge it? Like 3 feet ...
Güd morniiin, siis iiis di Frenchman spiiikin IInglis.
Don't take it seriously, your english is fine, your videos are great and in Germany you hear a lot of funny english accents, too.
Greetings from your neighbor Germany :)
Can a variable capacitor be used to precisely tune the carpet transmitter to the receiver?
Right, but radio ones have a to low value
mr sandman...bring me a dream...buh buh bah buh
Music name which was first played by guitar itself moving on carpet??
It's been a long time.
Primary and secondary both coil are on resonance frequency???
And is resonance frequency of both coil different??
Yes and it's the same frequency
We can see 5 resistors on the PCB. But in circuit diagram shows only 2 resistors?
I will appreciate if you could please guide.
Thanks.
👍🏻
probably 3 1kOhms resistors parallel to each other, to have a total of around 330 Ohms
Good day!
I have gotten the circuit diagram to this project at the end of the video...
I chose this particular project on this video as my project in the University, please 🙏 I want you to assist me with the components and a few details about them.
I would be very glad if you could grant me this request.
scott joplin "the entertainer" (second song)
Ahh... Sweet sweet metric!
Also why do you use linear regulator instead of buck converter?
Actually it would be better with a DC/DC regulator in a commercial efficient version to reduce the consumed power is short distances.
But the aim here is simply to get a constant power over the surface so the limiting point is the energy when the receiver is far from the emitter, to dissipate energy when the receiver is close is not an issue : we already get the required power so we don't care about the additional one! (but is drawn from the emitter anyway).
In our set up things are calculated the way that the linear regulator doesn't loose energy in the critical point in the center of the carpet.
@@DIYExperiments oh ok, so it was constructed as demo for tuned resonance.
I'd like to apply this same concept to charging an EV, any pointers?
What is the negative effect on human body of rays..?
I don't have this type of inductor, i have that which are use in adapter , charger circuit small size
what about the eddy current ,
How big could you make the magic carpet? Like if you could make it the size of the whole room or even the whole house
Or go even bigger the whole city block. Like I mean what are the limits, why don’t we do this so that we can have wirelessly powered everything in our homes and lives, it could work at least easily with charging stations and or home and city streets and everything. I mean obviously it wouldn’t be a good way to measure who was using how much, but there would be ways to do that, I mean even our stupid phones keep track of usage.
Very, very, very interesting video and very practical. I watched it all the way. Stuff to keep experimenting on. Probably I'll start experimenting on my own in this field of electric engineering. I'll watch the video again. One friendly advice - your english is good, but it can be a bit better. Sorry for giving you advice, I had to.
His english is perfectly fine!
Helal olsun sana.süper
Efficiency is not bad at all
Why not use copper wire instead of isolated wire?
Led is glowing ..but using rectifier with fast diodes mobile is not charging. DC voltage is coming at the output of rectifier...but I cant identify why mobile is not charging ...
With two circular loop of same diameter mobile is charging...but with a bigger loop mobile is not charging..can u plz help ?
Try this with a satellite dish!
After building a satellite dish. I would place a 3-foot jumper wire on the dish (that I just built & aimed at the satellite). I would take the 3 foot jumper wire, then screw it into my " super buddy" its the satellite aiming computer. And within two hours the 7.5 volt battery would be fully charged , using radio waves from satellites!
you can detail more or give a link of a document or a video please ? Thinks
Video ?!
Please share details of Electronics circuit
I tried making it and it doenst work...
Vewoui good accent ^^
@le sausisier lumineux coucou
My Father was a Self-Made Inventor. He was always creating Experiments. At age 5, I was told to touch a shiny metallic ball attached to some mechanism & my hair sprang up by maybe the Electrostatic Energy. Since then, I became very Electric! HA, HA.
Very good how homemade
Can I safely do this in my room. Idk about the electromagnetic radiation if there even is any. If so if I make a really strong wireless charger so I can do something like bring my iPhone within a certain area of my room and it automatically charges. How safe would that be? Could it give me cancer?
only emw which are ionizing can cause cancer
for instance 1000Thz
itss more than light frequencies
light is between 300-700THZ
so 100khz is tooo low
note:1THZ=1000GHZ , 1GHZ=1000HZ
Can we make carpet fly ?
You have made a good project can you please send me the circuit diagram of this project..
It appears at the end!
The entertainer
Thank you for your very good work!
I would like to know if you can make a video on solar energy please Thank you
So would doing this actually RAISE my electric bill?
When the Genie meets Star Wars. The days of the lithium battery are counted.
How much copper do you need to power a proverbial LC car through a city square?
Think this can be modified to power a car on a road? I think you need about 60 kw to power a car at freeway speeds.
Build a house with this technology. EMF affects my health?
How many AMPS did you use to make that works?
24V 2-3A