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Wireless Power Transfer Grid Could be the Answer to Powering Devices Across Thin Air

Written by Stephen Vicinanza

Earlier this year a study came out from Aalto University, describing a technique for charging wirelessly anywhere in a room. The wireless power transfer grid could be the answer to powering devices across thin air.

In the past safely charging devices, like smartphones, tablets, and devices that are connected to Bluetooth, in large areas like malls or airports has been a challenge.  Researchers have developed a method of charging, that doesn’t need to know the location of the device being charged.

The technology has been tested across several types of commercial devices, such as warehouse robots. There doesn’t need to be a plug, or the device touching the charging station, at all. There is even the capability to charge household appliances.

One of the more efficient benefits of this type of charging is that devices in motion can be charged. One day electric vehicles could be charged while in motion, no longer requiring a charging station at all. It’s all in the clever use of electromagnetic fields.

The technology in its basic form has been around for several years, but until now could not be applied in large spaces. Using a single large transmitter of the type that would be needed would expose the entire area to unwanted electromagnetic waves, and would be uncontrollable power, which would hamper where individual devices could be charged.

In order to use small transmitters, then the receiving devices must be in known positions, and the transmitter and receiver must be precisely aligned for the system to function. In the end, this means the system either has to have fixed charging locations or incorporate some type of positioning sensor, as well as communications protocols and some type of processing system to track the location of each receiver hench in each device.

The researchers at Aalto University have been working diligently on this particular problem and have come up with a method of charging that works regardless of the position and orientation of the transmitter or receiver. The key to this method is to arrange the transmitters in a grid with the current in the neighboring transmitter running in opposite directions.

To lay out what happens think of a chessboard, where transmitters are the squares and each square runs in directions that are the polar opposite of its neighbor. One transmitter sends out a clockwise loop of power, while the neighbor sends out a counterclockwise loop of the opposite polarity. Positive and negative polarities meet and overlap in a magnetic flux emitted from the corresponding coils.

All it takes is a receiver to come into the magnetic flux and it will accept a charge. The receiver triggers the transfer so that no tracking or orientation is necessary. The position does not matter because the transmitters offer a 360-degree transmission. It is a simple method, but quite a bit more sophisticated than anything tried so far.

So far the technology has been tested using commercial warehouse robots, in cooperation with Finnish companies. The hope of the researchers is to commercialize the technology for industry and transport. Prasad Jayathurathnage, who led the team in the research project offered thoughts on the project, citing a core impetus of simplicity and sophistication. “The beauty of our method is that it is very simple, yet quite sophisticated. We don’t need a high-end processor or lots of computations to make the transmitters intelligent. It’s all in the electromagnetic system, and our task was to determine and detect the receiver’s presence and position electromagnetically”

It seems that they have done just that.

To read more on the electromagnetic system that can charge devices across large open spaces, see the paper on the study here.

Shamsul Al Mahmud, Ishtiaque Ahmed Panhwar, Prasad Kumara Sampath Jayathurathnage. Large-Area Free-Positioning Wireless Power Transfer to Movable ReceiversIEEE Transactions on Industrial Electronics, 2022; 1 DOI: 10.1109/TIE.2022.3144591

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For the past 8 years, I have been writing about embedded technologies, added to my technical, academic, and medical editorial experience, with companies like Elsevier and Cambridge University Press. I tell people to read what I write, not try to pronounce my last name. I am always available for comments and suggestions you can reach me at and I promise I will take the time to reach back out to you. I live in the North East with my wonderful family.

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Wireless Power Transfer Grid Could be the Answer to Powering Devi…

by Stephen Vicinanza time to read: 3 min