The era when mobile phones can charge themselves just by being in a pocket is not far off. Domestic researchers have developed technology that allows wireless charging of electronic devices from anywhere in three-dimensional space.
A research team led by Professor Byun Young-jae from the Department of Electrical and Electronic Engineering at Ulsan National Institute of Science and Technology (UNIST) announced on the 12th that they are the first in the world to develop wireless power transfer technology using electric resonance that enables charging anywhere in three-dimensional space.
The basic principle of wireless charging is the electromagnetic induction phenomenon discovered by 19th-century British physicist Michael Faraday. Simply put, when current flows through a wire, a magnetic field is created around it, and the energy of this magnetic field generates current in another wire nearby.
Currently, wireless chargers (transmitters) create a magnetic field that vibrates at a specific frequency in a coil, transmitting current to electronic devices (receivers) that share the same frequency. This charging method, which utilizes magnetic resonance, has the drawback that the charging efficiency drops significantly if the position of the transmitter or receiver is even slightly misaligned due to the magnetic field's tendency to self-correct.
The UNIST research team created a wireless charger using an electric resonance method instead of a magnetic field. Unlike magnetic fields, electric fields do not point in just one direction and do not have the property of self-correction, so there is no need to worry about the placement or angle of the transmitter and receiver. The research team successfully optimized the electric field-based resonance by creating a specific structure in the receiver to increase charging efficiency.
The wireless charger recorded a wireless power transmission efficiency of 46% within a space of up to 2 meters in width, length, and height. Professor Byun Young-jae said, "In the past, researchers from the Massachusetts Institute of Technology (MIT) demonstrated that mid-range charging was possible using magnetic resonance, and we have improved this technology to enable charging from anywhere in three-dimensional space."
The technology developed by UNIST researchers can charge multiple devices simultaneously rather than just one at a time. Even when placing several receivers in the same space, the same charging efficiency was observed.
The researchers predicted that if this technology is further developed, it would be possible to automatically charge logistics robots and automated systems in smart factories, not just mobile phones. Currently, logistics robots need to move to a charging area after a certain period of work, but once this technology is commercialized, they could work while continuously charging wirelessly within the factory, enhancing efficiency.
The researchers explained that this technology could also be utilized for exploration and energy management in marine environments. Furthermore, as the technology advances, electric vehicles may be able to charge simultaneously within a certain area without needing to park precisely on the wireless charging pad.
Reference material
Advanced Science (2024), DOI: https://doi.org/10.1002/advs.202407827