Throw away the power cord and charge your smartphone wirelessly. A long time ago it was a dream for many people. But the fact is that wireless charging technology is already being used on the ground in some areas of life and will soon be used commercially on a large scale. Wireless charging technology is also increasingly discussed. We usually think of electricity and magnetism as related, so when it comes to the principle of wireless charging, most of it is based on or derived from the phenomenon of electromagnetic induction. Here's a detailed introduction to wireless charging technology.
Wireless charging technology comes from radio energy transmission technology, which can be divided into two ways: low power wireless charging and high power wireless charging.
Small power wireless charging usually adopts electromagnetic induction, such as Qi for mobile phone charging, but ZTE's ev wireless charging mode adopts induction. High-power wireless charging is often resonant (the way most electric cars are charged), in which power is transferred from a power supply device (the charger) to an electrically powered device that USES the energy received to charge the battery and at the same time provide for its own operation.
Because the charger and the electrical device transmit energy by magnetic field, there is no wire connection between the two, so the charger and the electrical device can achieve no electrical contact exposed.
In 1890, physicist and electrical engineer Nikolai Tesla was already experimenting with wireless power transmission. The SI system of magnetic induction is also named after him. The wireless transmission method conceived by Tesla is to take the earth as the inner conductor and the earth ionosphere as the outer conductor, establish a low frequency resonance of about 8Hz between the earth and the ionosphere by amplifying the transmitter in the mode of radial electromagnetic wave oscillation, and then use the surface electromagnetic wave around the earth to transmit energy. But due to the asset problem, Tesla's bold idea has not been realized. Although later generations have fully proved the feasibility of this scheme in theory, the world has not yet achieved great peace, and it is impossible to broadcast energy around the world and obtain it for free in a short time. So a great scientific idea was stillborn.
On June 7, 2007, the MIT team published their findings online in the American journal Science. The team managed to "catch" electromagnetic waves by using resonance to transmit them, using copper coils, one attached to the transmitting power and the other attached to the receiving power. When a transmitter sends out an electromagnetic wave of a particular frequency, the electromagnetic field diffuses to the receiver, and the power is wirelessly transmitted. The technology, which they call "wireless power", has been successfully tested to power a 60-watt light bulb two metres away. The technology's temporary bottleneck is its maximum transmission distance of 2.7 meters, but the researchers believe that batteries within this range can be wirelessly charged and even power appliances throughout the house, using only one power source.
When PC maker Dell joined the A4WP in February 2014, executives said they would upgrade the technology to enable wireless charging of ultrababs from dell and other PC makers. Most conventional laptops on the market have more than 50 watts of power, but ultraboods, which use Intel's low-power processors, will be the first laptops to be wirelessly charged. Until now, wireless charging technology has been associated only with "small" mobile devices such as smartphones and small tablets. However, A4WP(" Wireless Charging Alliance "), one of the three wireless charging groups, recently announced that its technical standard has been upgraded to support 50W related appliances, which means that high-powered devices such as laptops and tablets can also enjoy the convenient experience brought by wireless charging.