Technology

Wireless charging system for multiple devices

From the hand of a team of researchers at Aalto University comes a new wireless charging system, simple and low cost, using a single power source.

This new design has a cylindrical power coil at the heart of it all.

With a Z-shaped bridge, it connects to the wire at the top of the coil, which is wound in the opposite direction to the wire at the bottom of the coil. Current flows through these in opposite directions producing complementary magnetic fields.

The first field, if it could be called that, flows from the center of the coil, around the top winding and enters at the top; the other field does exactly the opposite at the bottom winding. Resulting in a uniform magnetic field around the center of the charging coil.

Receiving devices placed anywhere within the field area would charge efficiently regardless of position within the field.

“We set out to create a simple, low-cost system using only one power source,” commented Nam Ha-Van, the postdoctoral researcher who led the study.

“This was just a proof of concept,” commented Yining Liu, a Ph.D. candidate and research participant. This system by producing the doughnut-shaped field, offers a more comfortable and reliable design for users.

In creating the omnidirectional charger, a main challenge was presented from the beginning, the strength of the charging field changes with location, so devices if in the wrong place would charge inefficiently. Using multiple power supplies, would increase the complexity of the transmitter making the system impractical.

Orienting the power field using feedback could increase the cost of the system and is not the focus of this project. The team found a level that met safety requirements but requires further safety studies before implementation.

This new design made it possible to transfer power to multiple moving receivers in a charging area, addressing different systems of the wireless charging challenge, freedom of movement for industrial applications and free location for consumer devices such as mobiles, smart watches, tablet and so on.

The results have been published in IEEE Transactions on Industrial Electronics Journal. You can read the paper in open access by following this link https://ieeexplore.ieee.org/document/9720117

03 de Mayo, 2022