How does wireless charging work? It is slowly integrating into our lives.

2019-11-06 09:11:07 109

The Wireless Power Alliance (WPC)'s Qi wireless charging standard has a relatively promising market opportunity. Now is a good time to test the technology, then how it works, what it is, and its prospects. Millions of Apple ecosystem users are also using Qi for the first time on the iPhone 8 and iPhone 8 Plus. Various mobile phones have appeared in the past five years, and many people are using it. The basic technology has been used in consumer products such as razors and toothbrushes, as well as a variety of non-consumer tools.


Even if you haven't used Qi, you may be able to see the Qi wireless charging dock at the airport. As early as 2014, Verizon installed the Qi wireless charging station in several terminals from JFK to LAX in the United States. You will also see them in many other places, and devices such as the Samsung Galaxy S8 and the US version of the LG G6 can be connected. Googles Nexus4 phone has already supported Qi in 2012, but recently its not supported on Pixel phones.


Today we will introduce you how it works. Inductive Power Transfer Qi's main technology is called "inductive power transfer." We must be clear that the wires are still there, there must be a charging stand and need to be connected to a power outlet. You don't need to plug in your mobile device, but put it on the cradle.


The cradle will not be activated unless a compatible device has been placed. The station determines if there is a Qi-compliant device by sending an intermittent test signal. The mobile device responds to the device by transmitting the received signal strength. At this point, wireless charging begins. The charging base and the mobile device are respectively provided with a coil, a transmitter coil and a receiver coil. The coil of the transmitter generates an electromagnetic field that causes current in the receiver coil.


The receiver sends a signal to the transmitter that simply shares a value equal to the difference between the desired power level and the actual power level. The transmitter adjusts its output to achieve a zero difference between the request and the transmit level. All of these are delivered at a communication speed of 2 Kbit / s or less. When the receiver's charging is complete, the transmitter will automatically enter standby mode.


The first wireless charging dock for the iPhone 8 from Apple Partners is 7.5 watts. The Qi standard allows up to 15 watts and some Samsung chargers already support it. However, although these theoretical numbers look quite or even higher than wired chargers (the charger that comes with the iPhone is only 5 watts), these numbers are not everything. But the actual user experience shows that wireless charging is usually much slower than wired charging. It is worth noting that the placement problem is also the key. The coils are usually only a few millimeters apart and the production coupling between the coils requires precise alignment.


This is usually solved in one of three ways. The tactile signal feedback that charges the best position on the phone, but it poses a challenge when dealing with phones of different sizes and configurations. The cradle may have a coil that moves and aligns the coil in the device, allowing you to place it in any desired position, or a coil array like where a particular coil will be activated near the device. Inductive charging has always been at the heart of Qi, but similar technologies have recently appeared on the market, called "resonant wireless charging." Resonant charging is based on some of the same principles, but with different use cases. It can be charged over longer distances, but with lower transmission efficiency. Many newer devices support both modes, and adoption and replacement wireless charging technology has been around for many years, why do most people still use wires? This competitive standard, which often appears in technology, is a factor. In addition to Qi and WPC, we also have the AirFuel Alliance. It was born in 2015 with the merger of the Power Affairs Alliance (PMA) and the Radio Union (A4WP), but its market saturation lags behind Qi. The two standards under the AirFuel Alliance are not interoperable. However, AirFuel devices that meet AirFuel requirements will use both technologies in the same product, providing some flexibility in terms of charging and location.


In any case, competition standards break the balance of the market, making consumer and manufacturer acquisition levels less attractive. Even if each standard is supported by a mobile device, the added cost is inevitably applied to consumers. As you can see, there is still a need to refine the convenience and performance in the future, and it will always be updated and better technical results will bring us more convenience.