Introduction:
First, wireless charging: wireless charging technology (wireless? Charging? Technology; Wireless charging technology), originated from wireless power transmission technology, low-power wireless charging often adopts electromagnetic induction (such as Qi method for mobile phone charging, but ZTE's electric vehicle wireless charging adopts induction method), and high-power wireless charging often adopts resonance type (adopted by most electric vehicles). Power supply equipment (charger) transmits energy to electrical equipment, which uses the received energy to charge the battery and prepare for its own operation. Because the charger and the electrical equipment transfer energy by magnetic field, there is no wire connection between them, so both the charger and the electrical equipment can be exposed without conductive contacts.
Second, the basic principles
1. electromagnetic induction type: 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 transmitting end to the receiving end. At present, the most common charging scheme is electromagnetic induction. In fact, there is not much mystery in the technical realization of electromagnetic induction solution. As early as 65438+February 2005, China BYD Company applied for the patent of non-contact induction charger, which adopted electromagnetic induction technology.
2. Radio wave type: This is a mature technology, similar to the crystal receiver used in the early days. It is mainly composed of a microwave transmitter and a microwave receiver, which can capture the energy of radio waves bouncing back from the wall and maintain a stable DC voltage while adjusting with the load. This method only needs a transmitter installed on a wall plug and a "mosquito" receiver that can be installed on any low-voltage product.
3. Magnetic field vibration: The schematic diagram of wireless charging technology consists of an energy transmitter and an energy receiver. When two devices are tuned to the same frequency or vibrate at a specific frequency, they can exchange each other's energy. This is a technology being studied before a project. The research team led by Marin Soljacic, a physics professor at MIT, used this technology to light a 60-watt light bulb two meters away. The diameter of the coil used in this experiment reaches 50mm, so it cannot be commercialized. If the coil size is reduced, the received power will naturally decrease.