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Wireless mobile phone charging solution
1. Program introduction
In the fall of 2017, Apple launched its latest iPhone series, and one of its biggest updates was that the iPhone began to include support for wireless charging technology. Although Apple is not the first to "eat crabs", Samsung's Galaxy series phones already have a wireless charging function, but due to Apple's influence in the industry, the adoption of wireless charging technology in Apple's mobile phones not only makes people think Knowing more about this technology also shows that this technology is mature enough to be applied to products such as smartphones.
Compared with the traditional charger method, the biggest advantage of wireless charging technology is that it avoids the use of charging wires. After adopting wireless charging technology, different electronic devices can adopt a unified wireless charging standard, and only one charger is needed to charge different devices. Another advantage of wireless charging technology is that it is non-contact. For electronic devices, the non-contact charging method does not require an exposed charging interface and can achieve a better waterproof design. The charger can also be embedded in the base of the lamp, the table or even the bedside table, which is convenient for users to charge anytime and anywhere.
The emergence of smart phones has made people realize that mobile phones can not only be used to make calls and send text messages, but also can be used to surf the Internet and chat on WeChat. As people spend more and more time on mobile phones every day, various applications and screens consume more and more power, and the battery life of mobile phones has become a prominent issue. Especially when going out, the dead mobile phone will bring various inconveniences to people's life. In order to solve the above mobile phone charging problems, we propose a shared wireless charger design scheme that is suitable for indoor public places such as restaurants, cafes, train stations, and airports, and supports various mobile phones.
2. Existing technical routes and corresponding technical standards
2.1 Existing technical route
As early as the 1920s and 1930s, some scholars have begun to discuss the possibility of the concept of wireless power supply. The real breakthrough in wireless charging technology occurred in 2007, when a research team at the Massachusetts Institute of Technology successfully lit a light bulb 2 meters away. With the continuous development and improvement of wireless charging technology, there are currently two mainstream technical routes: electromagnetic induction wireless charging and electromagnetic resonance wireless charging.
The principle of electromagnetic induction wireless charging is the same as that of a transformer. There is a coil at the sending and receiving ends. The coil at the sending end is connected to a wired power supply to generate an electromagnetic signal. The magnetic field of the wireless charging system is mainly transmitted through the air, so the magnetic field transmission efficiency is low. If you want the wireless charging efficiency of the system to reach more than 70%, the two coils need to be very close together, and the coils need to be similar in size, with precise positioning between the two, and this technology can only support one-to-one charging. The principle of the electromagnetic resonance scheme is the same as the resonance principle of the sound. The primary coil and the secondary coil achieve energy transfer through magnetic resonance. The transmitter oscillates at a specific resonant frequency, and adjusts the resonant frequency of the secondary coil to be consistent with that of the primary coil, thereby realizing energy transfer. The charging distance of the electromagnetic resonance scheme can reach more than 45mm, and the range is large, not limited to the planar structure. At the same time, one-to-many charging can be realized. The secondary coil at the receiving end can be configured in different sizes to adapt to different device powers.
2.2 Existing Technical Standards
In order to promote the application of wireless charging technology, communication operators, semiconductor companies and high-tech companies have formed different wireless charging alliances and launched their own wireless charging technology standards. The most mainstream wireless charging standard is the Qi standard launched by WPC (Wireless Power Consortium). The traditional Qi standard uses an electromagnetic induction scheme. The Qi standard has good versatility and convenience. From homes, cars, to airports, cafes, and offices, the Qi standard supports a wide range of scenarios. Generally, wireless chargers with the Qi standard logo can supply power to electronic devices that support the Qi standard. In order to make up for the fact that the electromagnetic induction solution can only be charged one-to-one, the latest Qi 1.2 standard has added support for the electromagnetic resonance solution, which can charge multiple devices at the same time.
Another wireless charging alliance, Airfuel, has also launched its wireless charging technology standards, including the PMA standard using the electromagnetic induction scheme and the A4WP standard using the electromagnetic resonance scheme. However, compared to the Qi standard, Airfuel is technically immature and has not been well used commercially.
3. Our design plan
Our design mainly includes four modules: wireless charging module, user interaction module, central control module and remote server module. The function description of each module is as follows:
Wireless charging module: The wireless charging module is mainly responsible for realizing the charging function of the smartphone. There are currently two mainstream wireless charging technology routes: electromagnetic induction wireless charging and electromagnetic resonance wireless charging. Although the electromagnetic resonance wireless charging solution can support one-to-many charging and a longer charging distance, the electromagnetic induction wireless charging solution is more mature in technology and business. The Qi standard launched by the Wireless Power Consortium WPC (Wireless Power Consortium) is currently the most mainstream wireless charging standard. In the wireless charging module, we will also use a wireless transmitting coil that supports the Qi standard, so as to realize charging support for various mobile phones.
User interaction module: The user interaction module is mainly responsible for the realization of the interaction function with the user. In order to allow users to use our wireless mobile phone charger quickly and easily, we have adopted the user login method of scanning the QR code on WeChat. Users can directly use their WeChat account to log in to the mini program we provide, enter the number of the wireless charger around them, and obtain the permission to charge. After the user finishes charging, he can also pay the corresponding fee through WeChat payment and other methods.
Central control module: The central control module is mainly responsible for communicating with the remote server and controlling the opening and closing of the wireless charging function. After the remote server successfully authenticates the user identity, it will send a corresponding message to the central control module. After the central control module receives the charging start information sent by the remote server, it will turn on the wireless charging function. After the remote server sends a stop charging message, the central control module will turn off the wireless charging function.
Remote service module: the service module is as follows
(1) The user scans the QR code on the desktop to log in to the WeChat applet.
(2) The user enters the number of the wireless charger around him, clicks the start charging button, and puts the mobile phone on the corresponding position on the table to start charging.
(3) After charging is complete, the user clicks the button to stop charging.
(4) According to the fee prompted in the mini program, the user completes the corresponding fee settlement through WeChat payment.
4. Conclusion
This paper reviews the existing wireless charging technology routes and corresponding technical standards, and proposes a design scheme for a shared wireless mobile phone charger. Our design combines the Qi radio standard and various functions of WeChat software, which can provide a reference for future product design.
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