Among them, electromagnetic induction is to directly transmit and receive the current in the coil in the form of electromagnetic waves within a short distance below 1cm. Transceiver devices need to have high identification capability. Because electromagnetic waves radiate in all directions, a lot of losses and low efficiency, they are usually only suitable for low-power electronic products that are "attached" to each other. Electromagnetic vibration mode is to realize wireless power supply by using current to generate magnetic field vibration with the same frequency through coils. The strength of magnetic field determines its transmission distance and efficiency, which can realize indoor power supply, and the distance is about 10m. Microwave mode is to transmit electric energy to remote receiving equipment in the form of microwave or laser, and use it after rectification and modulation. Several technologies have their own characteristics. Recently, there has been a breakthrough in electromagnetic induction and electromagnetic vibration technology, which is more suitable for our daily application. In middle school physics textbooks, we all know that electricity is generated by the magnetic field of coil rotation and cutting. When coils with oscillation circuit characteristics are used in two devices to form a pair of transmitting and receiving antennas, one antenna transmits energy and the other antenna receives energy. When an AC electric field of several megahertz is applied to the transmitting coil, a magnetic field is generated around the antenna, and the electric energy is transmitted to another antenna at a certain distance through the same frequency vibration to realize wireless power transmission. Intel Seattle Lab has developed such a magnetic field coupled power transceiver, which can wirelessly power a 60W light bulb within two meters. Justin Rattner, chief technology officer of Intel, said that in the future, wireless charging equipment can be installed inside the desk, and power can be supplied immediately as long as the notebook and mobile phone are placed on the desk.
In the future, we can put wireless charging devices on the tops of offices, hotels and airports. As long as it is within the effective working distance of * * * vibration, we can immediately wirelessly charge notebooks and mobile phones, just as WiFi wireless Internet access is very popular now. We no longer need to carry a charger with us, worry about the mismatch of various interfaces, and use bulky batteries to extend the standby time. Or we can install a power transmitter on our wall, so that all household appliances can be charged wirelessly.
Microsoft has designed a desktop with wireless power supply, which will automatically start power supply just by placing a notebook, mobile phone, etc. On the desktop. 3. The coil determines the efficiency. Many R&D teams such as Intel are considering how to embed the wireless charging system into small devices, which needs to overcome many problems, such as the size of the receiving device, the limitation of transmission distance and the energy loss during transmission. Whether it is electromagnetic induction or electromagnetic vibration technology, the efficiency is related to the size of the coil that produces the magnetic field. If it is built into charging equipment and portable devices such as notebooks and mobile phones, it is necessary to simplify the size of the coil, which will naturally reduce the transceiver efficiency. Therefore, more advanced control chip and transceiver circuit design are needed to improve the transmission efficiency of wireless energy to more than 75%, so that the wireless power supply efficiency is higher and the charging time is shorter. At the same time, distance is also a big obstacle to wireless power transmission. The farther the distance, the greater the loss, and the less electricity the receiver can sense. But in general, when the natural frequency of the antenna at the receiving end is consistent with the frequency of the magnetic field at the transmitting end, it will produce * * * vibration. At this time, the magnetic field coupling strength is obviously enhanced, and the wireless power transmission efficiency is greatly improved. However, the frequency of this electromagnetic field may cause interference to other components inside the equipment. The finished product makes the application more convenient. After years of discussion and research, wireless charging technology is not an empty talk. At present, many such products can be seen, and some companies have their own technology patents. These technologies are different. They all have a special power transmitter with many coils, which can generate a magnetic field when electrified. There is also a receiving coil inside the receiver. When it is placed near the power transmitter, it can receive the electric energy generated by its internal magnetic field and transmit it to the battery inside the device to be charged. Many manufacturers provide many wireless charging schemes for mobile phones such as Apple and Motorola. WildCharge has designed a connector kit for this purpose. The connector consists of an induction coil and connects it to the charging interface of the mobile phone. After the installation, just put the phone on the charging board and you can start wireless charging. The total price of this connector and charging board is about $80. That is to say, wireless charging can be realized even if there is no wireless receiving coil embedded in current mobile phones and MP3 products, which undoubtedly lowers the threshold for ordinary products to enter wireless charging. In addition, WildCharger also introduced a high-power product, which can not only charge various mobile phones and MP4s, but also charge notebooks. WildCharge can charge all kinds of mobile phones through special interfaces. SplashPower introduced a wireless charger, Splash pads, which is similar to a mouse pad. You only need to put the device to be charged on it to start charging, and you can charge multiple devices at the same time. In the plastic film of the splash pad, there is a small coil array that generates a magnetic field, and the receiving end of the built-in magnetic receiving coil can be attached to the battery of electronic equipment. At this year's CES, Powercast exhibited a transmitter that can be installed on a wall plug and a miniature receiver that can be installed in any low-voltage product, which can charge batteries of different products with a radius of about 1 meter. The whole system is not complicated and the cost is low, as long as 5 yuan. Powercast claims to have signed cooperation agreements with companies that produce mobile phones, auto parts and hearing AIDS, especially those implanted in human bodies, which often require surgery to replace batteries. If the wireless charging system is used, patients will no longer have the pain of reoperation. To popularize wireless charging technology, it is necessary to form an internationally accepted standard, with wide compatibility between transceiver devices and interchangeability between products. At present, eight manufacturers, including Philips, Olympus, Sanyo and Texas Instruments, have formed the Wireless Charging Technology Association, and formulated the standards for the use of low-power electronic equipment below 5W, which means that the standardization of wireless charging technology has officially entered the implementation stage. In the near future, the new standard will make portable devices have the function of wireless power transmission, and make this charging process more convenient, eliminating the process of plugging and unplugging connectors. Finally, the realization of wireless charging technology has brought us more convenient applications and truly realized the meaning of "wireless". When all household appliances are wirelessly charged, we can say "goodbye" to the wire socket. At the same time, as a scientific research, wireless power transmission can drive the development of other scientific and technological fields, such as energy transmission between satellites, airplanes and automobiles. Any technology is a double-edged sword. When it is applied to practice, especially to household appliances closely related to human daily life, people will inevitably question it. Due to the poor directivity of electromagnetic wave transmission in space, the original little energy is consumed faster, the wireless transmission power is low, the overall efficiency is poor, and it will cause great electromagnetic pollution to the space, and the health of users will be affected without shielding. These are the reasons why wireless charging technology has not been well applied. Wireless charging technology may still have a long way to go. Even after wireless charging, how to manage the frequency is still a problem. At the same time, we need to transform the current mobile phone or equipment to a certain extent, so that it has a device that can accept electromagnetic waves, which may take some time. Therefore, manufacturers need to carefully weigh the advantages and disadvantages in the research of technology, so that technology can benefit mankind to the greatest extent.