1. Electromagnetic induction
The charging base and the mobile phone terminal have built-in coils respectively. When the two are close, the transmitting coil generates a certain current in the mobile phone receiving coil based on a certain frequency of alternating current through electromagnetic induction, so as to transfer the point energy from the transmitting end to the receiving end, and then start to supply power to the mobile phone from the charging seat.
Because the principle is simple and easy to make, coupled with the promotion of Texas Instruments, Philips, Toshiba, Microsoft, Panasonic, Samsung, SONY, Qualcomm and other manufacturers, this is the most popular way on the market. However, wireless charging based on electromagnetic induction also has disadvantages, among which the transmission distance is severely limited.
2 Magnetic resonance
A magneto consists of a large inductor coil with a small capacitor in parallel or in series, and the same resonant frequency is a necessary condition for energy transfer. For example, two coils are used as resonators, the transmitting end vibrates at 10MHz to radiate an electromagnetic field around, and the receiving end needs to vibrate at 10MHz to receive this transmitted energy.
Compared with electromagnetic induction, based on magnetic resonance, wireless charging achieves long transmission distance, efficient power supply, and is a one-to-many power supply method. However, because both sides need to be at the same resonant frequency at the same time, it is important to adjust the frequency of the circuit, but it is not so easy.
3 Radio waves
The principle is to convert the environmental electromagnetic wave into current and transmit the current through the circuit.
The transmission distance of this wireless charging method is greater than 10 meters, which is suitable for long-distance low-power charging, and can also realize automatic charging anytime and anywhere. However, because of the low conversion efficiency, if you use this method, the charging time will be longer.
4WiFi wireless charging
The charging system consists of two main components, one is a Wi-Fi access point (router), and the other is a custom charging sensor. It is worth noting that this method does not need to replace the traditional wireless router, only need to deploy software and other solutions, and the charging function can coexist with the Internet access function, will not affect each other.
The advantage is that it can be charged on the go, which is very convenient for users, and the disadvantage is that the charging object is not easy to locate, which is a waste of electricity.
5 Ultrasonic wireless charging
The idea is to use ultrasonic waves to send power 15 feet (4.6 meters) away. In this way, users only need to use a dedicated wireless charging case, and can hold the phone while charging around the house.
This technology is very safe, and the price of the receiver is also very cheap, the volume is also small, in addition to wireless charging, but also to achieve the transmission of data. However, the final product may not live up to expectations in terms of price, power, speed and safety.
6 Focusing Light
This is a new wireless charging technology \"AutoCharge\" developed by Microsoft. AutoCharge is described as a technology that automatically locates and charges a phone on a desk. The system consists of two modules, a monitoring module in the form of a camera with image processing function, and a charging module using UltraFire CREE XM-L T6 to focus LED light.