Wireless Charging Architecture

Wireless charging, also known as inductive charging, uses near-field induction, that is, the principle of inductive coupling. The power supply device (transmitting end) transmits energy to the electrical device (receiving end) and uses the received energy to charge the battery. Inductive coupling is used to transfer energy between the transmitting end and the receiving end. There is no need to use wires to connect. The charger and electric device can achieve a non-conductive contact design, eliminating the fetters of the charging cable and improving the convenience of the device.

At present, the main wireless charging technology, one of which is magnetic induction technology, uses the coil device at the transmitting and receiving end. Through the principle of electromagnetic induction, the coil at the receiving end induces the electromagnetic signal from the transmitting end, and electricity is generated to charge the battery through the change of magnetic field. Magnetic induction technology has a large distance limit. The maximum charging distance is about a few centimeters. It must be close to the transmitting end to charge. Although the charging efficiency is good, as the distance increases, the power loss will gradually increase. It is more suitable for mobile phones and mobile phones. Other portable electronic devices achieve convenient and versatile wireless charging technology. Currently, the Wireless Power Consortium (WPC) has formulated the magnetic induction standard “Qi” and the AirFuel Alliance (AFA) is responsible for promoting the AirFuel Inductive (formerly PMA) standard, which is composed of different alliance members.

Another wireless charging technology is magnetic resonance technology, which uses the resonance principle of the same frequency at the transmitting end and the receiving end to transmit energy with high efficiency. When both the transmitting end and the receiving end vibrate at the same frequency, the receiving end can receive the electromagnetic field generated by the transmitting end to receive energy transfer. Magnetic resonance technology can achieve a slightly longer charging distance at the expense of partial charging efficiency, and has better charging efficiency and supports multi-device charging. At present, it is mainly based on the AirFuel Resonant (formerly A4WP) standard promoted by the AirFuel Alliance (AFA).