Future-oriented E-zone
Inductive Charging Technology

The E-zone wireless power transmission technology operates with magnetic resonance involving natural vibration from an outer magnetic field. This future-oriented inductive charging technology allows electric/electronic devices to be charged automatically when they are placed within a certain space served by wireless LAN or upon charging devices in the form of cup holders or bookshelves. It demonstrates a high efficiency because it uses the frequency of 140kHz, with an antenna much smaller than the one used for the existing magnetic resonance method. In addition, the technology works with chargers of smaller sizes.

01

All-around
charging technology

Wireless power transmission technology has become widespread in recent years to charge smartphones, vacuum cleaners, or other electronic devices using electromagnetic fields, without the need to plug the devices in. More recently, the leisure and related industries are working to introduce the technology to drones as well. The wireless charging technology currently adopted for smartphones takes advantage of magnetic induction, which works well even with the contact of water or heat. Allowing devices to be charged on a flat pad, this charging method uses the phenomenon of electromagnetic induction: electricity running onto the pad creates an electromagnetic field, which makes the electric current flow around the receiver coil inside the mobile phone, charging the device. However, since smartphones must directly contact the charger or stay within a one-centimeter radius of the charger, it is difficult for users to charge their smartphones when they are on the move. Another downside is that phone calls cannot be made while charging. Due to these shortcomings, magnetic resonance began to draw attention as a future-oriented wireless charging technology that would allow inductive charging.
After a series of studies, ETRI researchers discovered that charging devices placed side by side through the magnetic resonance method would allow the control of the power transmission and create a quiet zone with constant energy density between coils, maintaining the charging efficiency in all directions. In addition, to fit smartphones, ETRI developed a 3D wireless charger for vehicles in the shape of cup holders and received a favorable response by introducing it at CES 2017, the world’s largest electronics tradeshow, held in Las Vegas, United States.

02

Technology created with tenacity and determination

While developing a wireless power transmission system based on the same concept used for wired charging circuits, researchers faced a series of challenges that taught them valuable lessons. For instance, they selected a PC monitor as an object to receive power wirelessly and realized a circuit after calculating the rated voltage and current. During the experiment, the monitor began to fume with white smoke and broke down with a pop, mainly because the researchers failed to supply appropriate voltage and current in response to the monitor’s changing power consumption. They began to study various measures to prevent such accidents and improve the design. As a result of their continued efforts and research, they finally prepared a faultless demonstration by realizing power control and circuit stabilization. Indeed, E-zone wireless power transmission technology is the fruit of ETRI researchers’ tenacious and determined commitment to perfecting their research.

03

Future-orientedtechnology

With the increasing variety of smart devices such as watches, virtual reality devices, and electric bicycles, the corporate world is paying growing attention to wireless charging technology. In this context, wireless power transmission technology is most suitable for future wireless telecommunications devices, including IoT devices, wearable devices, and human-implantable medical devices. The magnetic resonance method not only lengthens the distance of power transmission, but also outperforms the magnetic induction method in terms of efficiency. Challenges still remain, however: it is hard to reduce the device size because the coil is bigger than that used for the magnetic induction method, and improvements must be made for coil design and electromagnetic waves. Power transmission is expected to no longer involve wires once such technological issues can be addressed. Successful commercialization of the technology will most benefit the areas of IoT, wearable devices, and human-implantable medical devices. This latest technology is particularly good news for cardiac pacemakers and other devices that desperately need wireless power transmission technology. According to ETRI researchers, the market for wireless charging technology will be worth KRW 50.3 trillion by 2021. The arrival of the IoT era has led to the development of a wide range of devices, which are expected to expand the applicability of wireless charging technology to three-dimensional space.