The principle of wireless charging technology is actually very simple. "The so-called wireless charging technology has the same basic principle as the transformer, that is, the principle of' electricity generates magnetism and magnetism generates electricity' that we have learned in our middle school physics class. Take the mobile phone as an example. There is a magnetic core in the charger of the mobile phone, and a coil is wound around it, which can convert electricity into electromagnetic field, and the electromagnetic field can spread in space. At the same time, the mobile phone also has a corresponding receiving coil. After the receiving coil touches the electromagnetic field emitted by the charger, it can be charged by a certain circuit.
Electromagnetic induction is often used for low-power wireless charging, such as Qi method for charging the mobile phone, but ZTE's wireless charging method for electric vehicles adopts induction. [1]? . High-power wireless charging often adopts resonance type (most electric vehicles charge in this way), and the power supply equipment (charger) transmits energy to the power-using device, which uses the received energy to charge the battery and at the same time provides it for its own operation.
basic principle
electromagnetic induction
alternating current with a certain frequency in the primary coil generates a certain current in the secondary coil through electromagnetic induction, thus transferring energy from the transmission end to the receiving end. At present, the most common charging solution is electromagnetic induction. In fact, there is not much mystery in the technical realization of the electromagnetic induction solution. As early as December 25, BYD Company in China applied for the patent of non-contact induction charger, and used electromagnetic induction technology? [2]? .
magnetic field * * * vibration
consists of an energy transmitter and an energy receiver. When the two devices are tuned to the same frequency, or vibrate at a specific frequency, they can exchange each other's energy. It is a technology currently being studied. The research team led by Marin Soljacic, a physics professor at MIT, used this technology to light a 6-watt light bulb two meters away. The diameter of the coil used in this experiment reaches 5cm, which can not be commercialized. If the coil size is reduced, the received power will naturally decrease.
radio wave type
schematic diagram of wireless charging technology
This is a relatively mature technology, which is similar to the crystal receiver used in the early days. It mainly consists of a microwave transmitter and a microwave receiver, which can capture the radio wave energy bouncing off the wall and maintain a stable DC voltage while adjusting with the load. This method only needs a transmitter installed on the wall plug and a "mosquito-type" receiver that can be installed in any low-voltage product.