Working principle

Electromagnetic induction type: This is the most common wireless charging method and is also the most widely used. The principle is based on the phenomenon of electromagnetic induction. When current passes through a coil, a magnetic field is generated. If another coil that is not electrified is placed in this magnetic field, current will be produced in that coil. A typical electromagnetic induction wireless charging system consists of a transmitting system and a receiving system. The transmitting system has an internal coil in the charging base component. Alternating current passes through the transmitting coil to generate a magnetic field. After receiving the magnetic field, the receiving coil of the receiving system inside the electronic device generates electromagnetic induction, which in turn generates an induced electromotive force. After rectification, it charges the electronic device.

Electromagnetic resonance type: It achieves wireless power supply by generating a magnetic field of the same frequency through a coil when current passes through it. The transmission distance and efficiency are determined by the strength of the magnetic field. This method requires that the coils inside the energy transmitting device and the receiving device have the same vibration frequency. When the transmitting end and the receiving end reach resonance, energy transmission is achieved.

Radio wave type: It mainly uses microwaves for power transmission. Microwaves refer to electromagnetic waves with frequencies ranging from 30MHz to 300MHz. By installing an electromagnetic wave generator at the power supply, the transmitting antenna transmits energy to the receiving antenna, which then converts the electromagnetic wave signal back into electrical energy for the equipment to use. However, this method has a low transmission power and is only suitable for electronic devices with very low power.

Electric field coupled type: Also known as capacitive radio energy transmission, it transmits wireless energy by forming coupling capacitors through metal plates without using coils for electromagnetic induction. It transmits electricity by utilizing the induced electric field generated by coupling two sets of asymmetric dipoles along the vertical direction, and is suitable for long-distance charging of small and micro power.

Application scenarios

Smartphones: They are one of the fields where wireless charging is most widely applied. Many smartphone brands have launched models that support wireless charging. Users only need to place their phones on the wireless charger to charge them, avoiding the trouble of frequently plugging and unplugging the charging cable.

Smart wearable devices: such as smartwatches, wireless headphones, etc. These devices are compact in size and have high requirements for the convenience of charging. Wireless charging technology precisely meets this demand. For instance, some smartwatches are equipped with wireless charging bases, and users only need to place their watches on the bases to charge them.

Electric vehicles: Wireless charging technology for electric vehicles is one of the future development directions. When an electric vehicle is parked in a wireless charging area, energy is transmitted between the charging device on the ground and the receiving device at the bottom of the vehicle to achieve wireless charging. This charging method can avoid the plugging and unplugging of the charging cable, improving the convenience and safety of charging.

Smart home: In the field of smart home, wireless charging technology can be applied to various small household appliances, such as table lamps, humidifiers, air purifiers, etc. These devices are usually placed in fixed positions. Using wireless charging can make their use more convenient and also reduce the clutter of wires.