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[Wireless Charging] Trying to Create an Open Circuit by Using Possibly Some Sort of Gate

02/11/2019 2:41 PM

Hi,

I am working on a project for wireless charging. I am trying to create a 3 coil array, but the inside coil is using the turns of outer coils also. From the design itself, there are multiple points where the coil can get shorted from because there seems to always be a shorter path. The design itself is hard to describe other than that, but what I am trying to do is only use 1 coil at a time. To do this, the other 2 coils need to see some type of resistance that is higher than the coil I am trying to use. I thought about using TRIACs or optocouplers at those points (there are about 28 points) to create opens. I can give more info if needed, but I am looking for some ideas to create opens or to see higher resistance at certain points. I am open to mechanical, electrical, or any other ideas.

Thanks.

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#1

Re: [WIRELESS CHARGING] Trying to Create an Open Circuit by using possibly some sort of gate

02/11/2019 4:09 PM

If it's hard to describe, a picture (schematic) will help others understand what you are trying to do.

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#2

Re: [WIRELESS CHARGING] Trying to Create an Open Circuit by using possibly some sort of gate

02/11/2019 4:15 PM

Like this. The black trace is the common path between the two. The blue path is the shortest. The green path is the longest. If I energize the coil on the left, I do not want any current flowing through the center coil. So in essence I need the whole left side to be blue.

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#3
In reply to #2

Re: [WIRELESS CHARGING] Trying to Create an Open Circuit by using possibly some sort of gate

02/11/2019 4:15 PM

It's a 3 coil array but they are connected.

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#6
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Re: [WIRELESS CHARGING] Trying to Create an Open Circuit by using possibly some sort of gate

02/11/2019 5:34 PM

This doesn't make sense to me, what about overlap of the device, would it have to be placed directly over a particular coil? What about charging more than one device? ...or different size devices? It seems to me that you need all coils active all the time....Isn't there a variable amperage requirement? What is the goal of this project? You can over simplify something to the point that it is not reliable...not reliable = useless...jus sayin'

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#8
In reply to #6

Re: [WIRELESS CHARGING] Trying to Create an Open Circuit by using possibly some sort of gate

02/11/2019 5:39 PM

It would only work with 1 device. Only 1 coil needs to be active at a time. The center coil is using the turns of the outer coils. And yeah i know, it might end up being scrapped but im seeing how far i can take it.

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#4

Re: [WIRELESS CHARGING] Trying to Create an Open Circuit by using possibly some sort of gate

02/11/2019 4:19 PM
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#5
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Re: [WIRELESS CHARGING] Trying to Create an Open Circuit by using possibly some sort of gate

02/11/2019 5:33 PM

Thats what im doing, but imagine if instead of 3 separate litz coils, they were all connected as one piece. I know it sounds crazy and impractical, but im thinking of ways to make it work.

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#21
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Re: [WIRELESS CHARGING] Trying to Create an Open Circuit by using possibly some sort of gate

02/12/2019 8:58 AM

You are doing the impossible here. If you make it like one sort of coherent coil material and having 3 pairs of terminals for the adjustment it cant be done. There will be interference on passive terminals which you will have to definitely deal/ filter from your circuit. You save a coil material but add up that filtering thing.

Not unless you have 1 pair of terminal but moving, like the servo controls on buck /boost of an AVR. It can move through coils and the same time make adjustment of the field. But isn't it more costly than the existing? Isn't it?

IDK, I'll ask buddy James about it.

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#23
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Re: [WIRELESS CHARGING] Trying to Create an Open Circuit by using possibly some sort of gate

02/12/2019 9:06 AM

If it was on 3 pairs of terminals like a standard 3 coil array, I would imagine a triac at the end of each terminal to open up the terminals I am not using. I know it seems impossible but I’m just seeing how far I can push this crazy idea.

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#7

Re: [WIRELESS CHARGING] Trying to Create an Open Circuit by using possibly some sort of gate

02/11/2019 5:34 PM

The coil is flat.

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#9
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Re: [WIRELESS CHARGING] Trying to Create an Open Circuit by using possibly some sort of gate

02/11/2019 6:06 PM

What about using thin flat wire?

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#10
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Re: [WIRELESS CHARGING] Trying to Create an Open Circuit by using possibly some sort of gate

02/11/2019 6:10 PM

I am using a patented stamped coil design. Its done by metal stamping. I have the design made already. Its just filled with shorts at about 16 different spots depending on which coil is being used.

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#11
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Re: [WIRELESS CHARGING] Trying to Create an Open Circuit by using possibly some sort of gate

02/11/2019 6:25 PM

Well then all I can see is placing switches at your short locations....You have some way of locating the position of the device, that activates the proper coil...so you will need some electronics attached to the pad at some point, and some wires feeding your switches...So what are you looking for, a controller?

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#12
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Re: [WIRELESS CHARGING] Trying to Create an Open Circuit by using possibly some sort of gate

02/11/2019 6:29 PM

Ok im on the process of figuring out what switches to use. I was thinking surface mount optocouplers or triacs. The issue is that these drawing i attached is 1 layer. Theres another mirrored layer on top of it. Im not sure which switches to use. The microprocessor logic is simple to me of which ones need to be shut off. Its just a matter of what im gonna be using to “open up” the short locations. I’m not really sure what I could do in terms of mechanical. I dont want to physically break the path due to wear and tear.

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#13
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Re: [WIRELESS CHARGING] Trying to Create an Open Circuit by using possibly some sort of gate

02/11/2019 7:32 PM

So if you used triacs you would need to break the connections and insert the switches....and you don't want to do that....? Could the flow be altered magnetically? What about reversing the electron spin to alter the path?

https://www.rdmag.com/article/2017/12/researchers-manipulate-flow-electrical-current-using-spinning-light

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#14
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Re: [WIRELESS CHARGING] Trying to Create an Open Circuit by using possibly some sort of gate

02/11/2019 7:51 PM

Oh wow. Yeah. That looks like it can help, thanks. Any idea where i can find more info on this or about redirecting the flow magnetically?

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#16
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Re: [WIRELESS CHARGING] Trying to Create an Open Circuit by using possibly some sort of gate

02/11/2019 8:33 PM

Well you might need to break some new ground here...

https://phys.org/news/2018-05-current.html

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#22
In reply to #10

Re: [WIRELESS CHARGING] Trying to Create an Open Circuit by using possibly some sort of gate

02/12/2019 9:03 AM

Don't disclose your ideas on this forum. People here are like Chameleon. They strike faster and smarter than you think. Later you will realize the thing you thought about has been patented by somebody else already.

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#24
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Re: [WIRELESS CHARGING] Trying to Create an Open Circuit by using possibly some sort of gate

02/12/2019 9:07 AM

I was trying to find out how to delete the thread haha.

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#19
In reply to #9

Re: [WIRELESS CHARGING] Trying to Create an Open Circuit by using possibly some sort of gate

02/12/2019 8:16 AM

Wow! Thanks SE. I got it.

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#15

Re: [WIRELESS CHARGING] Trying to Create an Open Circuit by using possibly some sort of gate

02/11/2019 7:52 PM

Good luck.

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#17

Re: [Wireless Charging] Trying to Create an Open Circuit by Using Possibly Some Sort of Gate

02/12/2019 4:22 AM

I realize you do not want to use relays because of reliability issues,but today's miniature relays are very reliable.

I would suggest using a snubber(clamping) diode on the output because of high inductive load.

Here is a link that may be helpful:

https://numato.com/product/16-channel-relay-controller-board

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#20
In reply to #17

Re: [Wireless Charging] Trying to Create an Open Circuit by Using Possibly Some Sort of Gate

02/12/2019 8:45 AM

It would need to be a switch on the actual coil itself. And there are already diodes to protect from back emf due to inductive load.

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#27
In reply to #20

Re: [Wireless Charging] Trying to Create an Open Circuit by Using Possibly Some Sort of Gate

02/13/2019 5:32 PM

This chip incorporates 16 contacts internally.They can switch 7 amps.

Connect them as needed. Check out the link I provided.

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#18

Re: [Wireless Charging] Trying to Create an Open Circuit by Using Possibly Some Sort of Gate

02/12/2019 8:15 AM

Is it the I gate or the U gate?

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#25

Re: [Wireless Charging] Trying to Create an Open Circuit by Using Possibly Some Sort of Gate

02/13/2019 6:04 AM

You might be finding that since the coils share a common (air) core, they are magnetically connected, in that all flux going through one must by necessity go through all the others and thus you are creating a three coil transformer.

Even if the other coils have open circuit, they will still develop voltage dependant on the current and number of turns of the energised coil.

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#26
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Re: [Wireless Charging] Trying to Create an Open Circuit by Using Possibly Some Sort of Gate

02/13/2019 7:21 AM

Even with the coils separated in a normal 3 coil array, you tend to see losses in efficiency because of what you described. Any loss in efficiency won't affect us too much. I think the ferrite would help too.

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