How does wireless charging work?

In recent years, more and more smart phones are equipped with wireless charging devices. Wireless charging has gradually entered our life. I don't know if you have ever wondered, no data cable wireless charging, its principle is exactly what?

At present, there are four basic wireless charging technologies: electromagnetic induction, magnetic resonance, radio wave and electric field coupling. Different wireless charging methods have different characteristics.

1. Electromagnetic induction

The fundamental principle is to use the principle of electromagnetic induction, similar to a transformer, the primary coil of a certain frequency of alternating current, through electromagnetic induction in the secondary coil to produce a certain current, so as to transfer energy from the transmission end to the receiving end. The conversion efficiency is high, the cost is cheap, but the transmission distance is short, easy to be affected by the location.

2. Magnetic resonance formula

It is composed of an energy sending device and an energy receiving device. When the two devices adjust to the same frequency, or resonate at a specific frequency, they can exchange each other's energy. Its principle is similar to that of sound resonance, but it is difficult to miniaturize and achieve high efficiency.

3. Radio wave type

By configuring radio wave transmitting equipment on the power supply side and radio wave receiving equipment on the power receiving side, power transmission is carried out in the form of DC voltage output and input. The transmission speed is relatively fast, but the security is low.

4. Electric field coupling formula

The induction electric field generated by two sets of asymmetric dipoles coupled along the vertical direction is used to transmit electric energy. The basic principle is to transfer electric energy from the sending end to the receiving end through the electric field. It is suitable for short distance charging, high conversion efficiency, and the position can not be fixed, but it requires a large volume of equipment and low power.