The alternating current of a certain frequency in the primary coil generates a certain current in the secondary coil through electromagnetic induction, so as to transfer energy from the transmitting end to the receiving end. At present, the most common charging solution adopts electromagnetic induction. In fact, the electromagnetic induction solution does not have much mystery in the technical implementation. China's local BYD Company used the electromagnetic induction technology as early as the patent for non-contact induction charger applied in December 2005 [2].
Magnetic resonance of the car charger
It is composed of an energy transmitting device and an energy receiving device. When the two devices are adjusted to the same frequency, or resonate at a specific frequency, they can exchange energy with each other. It is a technology currently being studied. The research team led by Marin soljacic, a physics professor at the Massachusetts Institute of Technology (MIT), used this technology to light a 60 watt bulb two meters away, And named it WiTricity. The coil diameter used in this experiment reaches 50cm, which can not be commercialized. If the coil size is to be reduced, the received power will naturally decrease.
Radio wave type of the car charger
This is a relatively mature technology, similar to the ore radio used in the early stage. It is mainly composed of microwave transmitting device and microwave receiving device, which can capture the radio wave energy bouncing back from the wall and maintain a stable DC voltage while adjusting with the load. This method only requires a transmitter installed on the wall plug and a "mosquito" receiver that can be installed on any low-voltage product.