Electronics have revolutionized our lives and industries, but the inconvenience and danger of wires still exists. To address this, wireless power transmission and reception technologies, such as magnetic induction and magnetic resonance, can be utilized in a variety of fields and have the potential to revolutionize our lives.
Compare life 500 years ago to today. One of the most revolutionary differences is the presence of electronics. From tiny light bulbs to giant refrigerators, it’s hard to imagine our lives without them. This is because electronics have become an increasingly important part of our lives. Many of them don’t use much power, such as a flashlight or remote control, and only need a battery or two to operate, while others, such as TVs and chargers that consume a lot of power, need to be plugged into an outlet to work.
These electronics have changed almost every aspect of our lives. Five hundred years ago, people lit the night with candles, salted food to preserve it, and had a completely different lifestyle than we do today. The invention of electricity and electronics not only transformed our daily lives, but also industries and economies. Electric motors and machines have greatly increased productivity, and the development of information and communication technologies has connected the world in real time.
In our daily lives, wires are ubiquitous, but their familiarity blinds us to their inconvenience and danger, and we seem to take them for granted. Imagine playing a game like the people in one of the company’s commercials, hunting for an outlet and plugging your phone into a charger. From a practical point of view, wires that limit the range of use are a huge inconvenience. They limit the product’s radius of use from the outlet to the length of the wire, which naturally reduces the product’s utility. Imagine plugging in a charger for an electronic device that you need to carry around and use, and you’ll realize the inconvenience.
From a safety perspective, wires also pose a number of risks. We’ve all seen the stories of tangled wires that short-circuit and start fires, and if your body comes in contact with an uncovered wire and gets electrocuted, it can be fatal. The same is true for product design. The presence of wires can be visually intrusive, and the terminals for plugging them into a product can be a distraction from the product design. Because wires have always been both necessary and inconvenient, technologies are being developed to transmit and receive power without wires.
Wireless power transmission and reception is a technology that converts and transmits electrical energy into a wirelessly transmittable form without the need for wires between products, and was proposed by Tesla in the 19th century. Practical wireless power transmission and reception technologies are divided into two main types based on their methods and principles: magnetic induction and magnetic resonance.
The first, magnetic induction, utilizes the phenomenon of electromagnetic induction, which was discovered and mathematically described by Michael Faraday. Electromagnetic induction is the phenomenon that causes a voltage, or potential difference, in a conductor where the magnetic field changes. When a magnet is repeatedly inserted and removed from a coil, current flows through the coil, which is the phenomenon of electromagnetic induction. The magnetic induction method, a wireless power transmission and reception technology, utilizes the phenomenon of magnetic induction between the primary coil of the power transmitter and the secondary coil of the power receiver. When current flows through the primary coil and generates a magnetic field, current flows through the secondary coil and transfers electrical energy to the product. It is easy to transmit and receive relatively large amounts of power, and it is also used to charge cell phones manufactured by some companies. There is even an international standard set by the World Wireless Charging Association, so it is considered a mature technology that has been commercialized and standardized. Although it is highly efficient, with a maximum power efficiency of 90%, it cannot be transmitted or received at a distance of more than 41mm, so it cannot be said to be wireless. In addition, the center of the primary and secondary coils must be exactly in a straight line to efficiently send and receive power, and if they deviate from a straight line even slightly, the efficiency drops dramatically, which is considered to be a point to be improved in the future.
Another way to send and receive power without wires is through magnetic resonance. As the name suggests, the phenomenon that this technology utilizes is resonance. Every object that is not at absolute zero has a unique frequency that vibrates at a frequency too small to be felt by humans, called its natural frequency. At this time, the phenomenon that the amplitude increases significantly due to the regular transmission of vibrations of the same frequency as the natural frequency from the outside is called resonance. Applying this phenomenon, when a resonant coil with the same natural frequency is attached to a power transmitter and a power receiver, the amplitude increases, which means an increase in power. This overcomes the problem of transmitting and receiving distance, which has been a problem with magnetic induction. Even if the receiver and transmitter are located 1 meter apart, the power efficiency is 90%, which means that power can be transmitted and received efficiently over longer distances.
Currently, the most common application of wireless power transmission and reception is in the field of charging. While this is less of a concern for products that can be charged separately, the need for wireless charging technology is quite urgent for all-in-one cell phones with non-removable batteries. Other products that will benefit from this technology include electric toothbrushes that can no longer be powered by the small voltage of a battery, televisions, computers, and laptops that want to hide the presence of unsightly wires.
Wireless power transmission and reception is still in its infancy. The inconvenience of not having wires still outweighs the benefits of this technology. There are still many more mountains to climb, and many more problems to solve. From a practical standpoint, discussing how this technology will be used right now is like asking a child to prove Fermat’s Last Theorem. While the technology itself is relatively new, the market is rapidly taking shape and appears to be maturing; in fact, the market size has grown several orders of magnitude in recent years. At the same time, however, we cannot overlook another side effect of wireless power transmission and reception technology. The increased power losses associated with wirelessly transmitting power in all directions, as opposed to efficiently transmitting and receiving power in a limited number of directions through wires, can be costly. Furthermore, the effects of power in the form of electromagnetic waves on humans and other electronics must be thoroughly validated. This is all the more important because electromagnetic waves are invisible and can be exposed for longer periods of time than they would otherwise be. As the Internet of Things develops, the transmission of malware or viruses through the wireless transmission and reception of power is also a concern.
In this context, wireless power transmission and reception technology is expected to open up new possibilities in various industries. In the medical field, wireless technology can be used to remotely charge or control medical devices inserted into a patient’s body, which can greatly reduce patient discomfort. In addition, as smart home technology advances, it can help create a more efficient and convenient living environment by wirelessly connecting all electronic devices in the home. For industrial robots and drones, wireless charging can extend their working time and increase productivity. Considering these points, wireless power transmission and reception technology has the potential to revolutionize many fields beyond simply eliminating wires.
Therefore, wireless power transmission and reception is a technology that gives us great hope for a world without wires. While there are still many problems to solve and challenges to overcome, the potential for advancement is enormous. We hope to one day have a world where all electronics are powered by wireless power, and this will require constant research and development.
