With the development of science and technology, various electronic products have emerged: mobile phones, watches, psp, mp3, iPod... They provide wireless convenience for our lives and greatly enrich our spare time life. However, various This kind of charger gives us a headache! The charger models of various electronic products are different, making it difficult to achieve good compatibility. However, the development of wireless charging technology has provided us with the best solution for charging portable electronic products, allowing all electronic products to be charged at any time as long as there are wireless charging equipment, greatly reducing our burden.
Wireless charging theory is not a new technology. There have been many laboratories conducting research on this technology for hundreds of years. Due to the low efficiency of wireless charging, extremely short distance, poor safety and other factors, the promotion of this technology has been hindered. At this stage, the emergence of certain new materials and technological advancement have overcome the above shortcomings to a certain extent. The popularity of small household appliances and handheld terminals has provided a broad space for the marketization of low-power wireless charging, making it more suitable for the requirements of modern life and improving the quality of life. The development of the new energy industry has further promoted the innovation of this technology.
1. Development of wireless charging technology
In the 1830s, Faraday discovered that changing magnetic fields could produce electric current; then Tesla, one of Edison's assistants, also proposed the idea of wireless power transmission;
Professor Xu Shuyuan from the Department of Electronic Engineering of City University of Hong Kong successfully developed a "wireless battery charging platform" in the early years, which requires the product to be in contact with the charger. It mainly uses the principle of near-field electromagnetic coupling.
In 2007, Marin Soljasik and others from the Massachusetts Institute of Technology in the United States made new progress in wireless power transmission. They used a power supply two meters away to light a 60-watt light bulb "remotely". .
On September 1, 2010, the Wireless Power Consortium (WPC), the world's first standardization organization to promote wireless charging technology, announced in Beijing that the Qi wireless charging international standard would be the first to be introduced into China. The WPC standard defines the types of inductive coupling (coil structures) and communication protocols used by low-power wireless devices.
Brett Lewis, vice chairman of the Wireless Charging Alliance, said that there are nearly 60 alliance members, including Energizer, LG Electronics, Nokia, etc.
Beijing time on November 9th, according to foreign media reports, the British company haloipt recently successfully implemented wireless charging for electric vehicles in London using its latest inductive power transmission technology.
At this point, wireless charging technology adopts a unified industrial standard. In the next few years, mobile phones, MP3 players, digital cameras, notebooks, etc. will all use the same wireless charger. It can be said that certain industry standards have initially been formed in this field. The wireless charger currently on the market was invented by a British company. It looks like a mouse pad and is equipped with a dense array of small coils, which can generate a magnetic field and transmit energy to electronic devices with receiving coils for charging. , this receiving device can be easily attached to electronic devices like chewing gum. But so far, wireless charging technology still cannot be implemented well on high-power devices.
2. Principles of wireless charging technology
Currently, there are three main methods of wireless charging: electromagnetic induction, radio waves, and electromagnetic resonance.
3. Industry status of wireless charging products
As we all know, many people think that we live in a world surrounded by cables, which is troublesome, unsightly and environmentally friendly. This is why the idea of wireless charging was born. Although so far, various research institutions at home and abroad seem to have achieved There has been some progress, but it has always stayed in the low-power, short-range charging mode, and most international wireless charging research is developing in the direction of high-power and long-distance. Perhaps greater progress will be made in 20 years. Success, but no one can predict the future development.
Scientists and engineers have long known that transmitting electrical energy does not necessarily require wires to be in physical contact at all times, such as the coils in electric motors and transformers. They can transfer energy to each other through the phenomenon of electromagnetic induction. Scientists have also discovered that radio waves contain electromagnetic radiation, but the efficiency of transferring energy from one point to another through traditional electromagnetic radiation is very low, because electromagnetic waves will spread around in the air, causing most of the energy to be lost. And this approach is also very dangerous, especially when the amount of electromagnetic radiation exceeds the range that the human body can bear.
Moreover, wireless charging systems that use electromagnetic waves to transmit energy also have two major problems: first, the transmitter is still emitting energy when there is no device to be charged on the charging device, which will cause a waste of energy if it is not used for a long time; second, When a metal foreign object is placed on the transmitter, the electromagnetic waves will heat it, which will inevitably damage the device, or even cause a fire.
Secondly, some wireless charging products have been unable to be put on the market in batches after perfect performances. Why? Because any electronic component must undergo precise debugging and calibration by professionals before leaving the factory. Similarly, if wireless charging products want to achieve a good electromagnetic resonance effect to achieve power transmission, they must undergo precise adjustment. In such a situation Under such circumstances, mass production will become very difficult.
Finally, the cost of wireless charging products developed now is many times more than the price of an ordinary charger. No matter how advanced the product is, it is just a charging device after all, so if you want to promote it, you must work hard to reduce costs.
4. Exploration of new directions in wireless charging
First, to improve efficiency in a wireless charging system, it is necessary to minimize the magnetic energy loss between the transmitting and receiving coils. To achieve this goal, high-frequency and high-current equipment can be added to the transmitting coil to boost the transmit signal. By establishing an intelligent frequency following system and cooperating with LC resonance, a high magnetic potential magnetic field can be emitted. Due to the existence of high magnetic potential , can achieve the purpose of minimizing magnetic leakage, and install a certain magnetic field automatic search device in the receiving part to make the system work as efficiently as possible. And a certain magnetic field shielding device can be installed to reduce the harm of electromagnetic waves to the human body, and a certain coil can be wrapped in the shielding device to recover the magnetic energy that is not accepted by the receiving device, thereby improving the efficiency of the equipment.
To solve the second problem, it can be achieved in this way: install a magnet on the receiving end, and only start sending energy when the transmitting end senses the magnetic force. This method is simple and feasible, because no one will accidentally put a magnet on the transmitter. Let it burn down on the device.
To solve the mass production problem, the design of the wireless charging system must first focus on the resonance part so that the device can self-adjust. Only in this way can the mass production problem be solved. And if you want to reduce costs, you must do it in the form of chips, so that it is possible to reduce costs as much as possible.
Furthermore, in view of the industry reality that most of the current wireless charging research focuses on high power and long distance, my opinion is that the focus can be slightly shifted and the wireless charging technology should be made as refined as possible. Since it is still Wireless realizes high power and long distance transmission, so why not develop into low power and medium distance? In fact, if this goal can be achieved, its application in the future electronic market is still very promising.
We can use this technology to transform existing batteries. In various fields where disposable batteries are currently used, secondary batteries plus wireless charging can be used to reduce the use of disposable batteries. Since the battery is equivalent to a ball of metal, we can place a receiving coil inside the battery. The alternating magnetic field generated by the transmitting coil will cause the metal in the battery to generate eddy currents, which is converted into heat. At the same time, a reverse magnetic field is generated to offset the generation of the transmitting coil. The strength of the magnetic field causes the voltage received by the receiving coil to drop. In order to reduce the eddy current in the battery, a material that blocks the magnetic field must be placed between the battery and the receiving coil. This material is often called a "magnetic shielding material." However, the current research on this material is mainly focused on the environment with a strong magnetic field of 50Hz. There is almost no research on the strong magnetic field around 100KHz used in wireless charging, so this may be a direction for future development.
Overall, wireless charging can be used in many imaginable and unimaginable fields. What is currently achievable include: low power and low energy consumption electronic communication products and office products, such as mobile phones, PDAs, etc., as well as furniture products and low energy consumption home appliances. The application fields that are currently being expanded include transportation, such as electric vehicles, EMUs, etc. Future long-term target areas include: space stations, satellites, warships and aircraft carriers, etc. It can even collect ionospheric energy from clouds and wirelessly transmit it to places that need energy, and it can be used in a new generation of international military fields that are completely environmentally friendly and energy-saving. Furthermore, in the specific promotion of products, another problem that needs to be faced is the formulation of industry standards. At present, there are no other industry standards except WPC. Therefore, in order to achieve final universality, all research directions should finally achieve a certain degree of "grand unification" and have a relatively mature and complete set of standards and protocols, so that the entire industry can truly Only by realizing universality can it be more convenient for users. While bringing wireless convenience to customers, it can greatly reduce the number of wired chargers and reduce the heavy pressure of electronic waste on the environment. It is the real convenience of our lives. Cleanliness.
5. Conclusion
The development of wireless charging technology is bound to bring wireless convenience to our lives. Perhaps some time in the future, all kinds of mobile phones, tablets, razors, cameras, toys, etc. around us will say goodbye to various chargers, and our lives will no longer be interrupted by various wires. At that time, we only needed to place our electronic products on a tablet-sized board to charge them. We should believe that under the background of the rapid development of existing technology, wireless charging technology should still be able to make greater progress in the next few years, so stay tuned.
