With the advancement of technology, wireless charging has also emerged. The wireless charger is a charger that does not use a line. It wirelessly transmits electrical energy to the battery cells through the coils. Simply charge the battery and receiving device on the charging platform. The energy transmission efficiency is high, and it is easy to carry one of the research directions of the charging system. Then this issue is a small series for everyone to explain in detail the knowledge of wireless chargers.
1. Introduction to wireless charger
The wireless charger refers to a charger that is connected to a terminal device that needs to be charged without a conventional charging power cord. The latest wireless charging technology is adopted. The wireless charging technology has obtained 20 patents in 2007, and one device can be used for multiple devices. Wired charging of charging base stations, mobile phones, MP3 players, power tools and other power adapters will not exist. By using the magnetic field generated between the coils, the magical transmission of electrical energy, inductive coupling technology will become a bridge connecting charging base stations and equipment.
2. Wireless charger principle
The wireless charging system mainly adopts the principle of electromagnetic induction, and energy transfer through the coil is realized by energy coupling. As shown in the figure, when the system is working, the input terminal converts the AC mains into a DC power through the full-bridge rectifier circuit, or directly supplies the system with a 24V DC terminal.
The DC power output after the power management module is converted into high frequency alternating current by the 2M active crystal oscillator to supply the primary winding. The energy is coupled through two inductor coils, and the current output from the secondary coil is converted into direct current by the conversion circuit to charge the battery.
A changing magnetic field produces a changing electric field. A changing electric field produces a changing magnetic field whose magnitude is related to their rate of change. The rate of change of the sinusoidal function is another sinusoidal function, so the electromagnetic wave can propagate out and the induced voltage The generation is related to the change of the magnetic flux, so the magnetic field that changes inside the coil generates an induced voltage, thereby completing the charging process.
Mobile phone wireless charging is a relatively new charging method, the principle is actually very simple, is to separate the main transformer secondary and secondary to achieve wireless purposes. Of course, the wireless charging frequency is relatively high, and even the core can be abandoned to directly achieve the energy transfer between the coils.