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Recently, with OPPO joining the Wireless Charging Alliance, the alliance has 190+ corporate members. In terms of quantity, it has begun to take shape, and wireless charging seems to have taken another step forward in our daily lives... Noble Origin Since its birth, wireless charging for mobile phones has only been standard on high-end models, such as iPhoneX, Samsung S9 series, etc. These models are all models that require selling a kidney to get started. Although some domestic mobile phones have also added wireless charging functions in recent years, they are all flagship models of their respective brands. Such a noble origin, but its background technology principle is the knowledge taught in high school physics. In the 1830s, Michael Faraday discovered that changes in the surrounding magnetic field will generate current in wires. Faraday's law of electromagnetic induction: e(t)=-n(d)/dt The core of the wireless charging system is the principle of electromagnetic induction, which realizes energy transfer through energy coupling through coils. As shown in the figure:405425When the system is working, the input end converts the AC mains into DC through a full-bridge rectifier circuit, or uses the DC end to directly power the system. After passing through the power management module, the DC output is inverted into high-frequency AC to supply the primary winding (the power transmission coil in the figure above). Through the two inductor coils to couple energy, the current output by the secondary coil (the power receiving coil in the figure above) is converted into DC through the receiving conversion circuit to charge the battery. A changing magnetic field will produce a changing electric field, and a changing electric field will produce a changing magnetic field. The magnitudes of these two fields are related to their rates of change, and the rate of change of the sine function is another sine function. In this way, alternating electromagnetic waves can propagate, and the generation of induced voltage is related to the change of magnetic flux, so the changing magnetic field inside the coil generates induced voltage, thereby completing the charging process. It's just that the operating frequency used in mobile phone wireless charging is relatively high, and the iron core that enhances the magnetic field can be completely abandoned and the coupling between coils can be used directly to achieve the effect of energy transfer. Perhaps it is because of the popularization of new technologies, or perhaps it is because of the traditional concept of wired connection. Although wireless charging has not yet been widely popularized, and although its technical principles are relatively simple, its noble origin is still beyond doubt. Flashy Before going to bed, when we return to our desk, we only need to gently place our mobile phone on the wireless charging base. With a low beep, the phone starts charging. Enjoying the full sense of future technology, you no longer have to worry about where that naughty mobile phone data cable is, and you no longer have to put the necessary three-piece set in your bag - charging head, charging cable, and power bank. In today's world where all kinds of digital devices are wireless, why is the popularization of wireless charging, which is simple in principle and implementation, so slow? Apple, the leading symbol of the technology industry, has also limited the power of wireless charging for iPhone phones, mainly because there are still many problems that need to be solved for wireless charging: Charging efficiency Currently, the transmission efficiency of wireless charging is still low. Not only is electromagnetic radiation non-directional, energy will be wasted in useless space, and heat is inevitably generated during the magnetic-electric and electric-magnetic conversion process - all of which are losses. From a data perspective, the current wireless charging efficiency is only up to 79%, and generally around 60%, which means that less than half of the electricity is wasted - a bit unfavorable for building a conservation-oriented society. The key is that consumers need to pay for this wasted energy. As a consumer working "996", I don't want to do that anyway! Charging speed issue In the current wireless charging solution - taking the Qi standard as an example - the maximum charging power is still around 10w, compared to the charging power of wired chargers USB PD and QC4.0, which has reached 28w. In other words, wired charging takes more than half the time of wireless charging, and wired charging is more popular with users. Problems caused by magnetic radiation Changing magnetic fields will produce a demagnetizing effect. If the bank cards commonly used in our lives happen to be placed next to the wireless charging base, they may become unusable due to demagnetization, causing inconvenience in life. Even IC chip cards such as ID cards and bus cards have a certain probability of failure due to high-energy radiation. Unfortunately, the only way to effectively avoid it now is to keep the above items away; Human health issues In our lives, there are not so many magnetic fields, and wireless charging devices break this natural law. What is the impact on physical health? Although there is no conclusion yet, who is willing to be that "little white mouse"! Through accumulation Since ancient times, "the world will eventually unite after a long period of division". Now the wireless charging standard Qi standard of the Wireless Power Consortium has been widely popularized in the market. The industry promotion based on a unified standard can reduce the R&D risks of downstream enterprises and reduce the technical costs of terminal product R&D for users. With the participation of OPPO, if its own super fast charging technology (VOOC flash charging) is applied to wireless charging technology, the current charging power of less than 10w will be increased to at least 15w, shortening the charging time by more than 30%, which will greatly improve the user experience. After Apple mobile phones actively limit the wireless charging power, it is believed that they will also lift the limit on wireless charging power after solving related problems. After all, the 20w power of wired charging has verified the hardware reliability of the battery and the body. Generally speaking, there are still many functions and technologies that can be improved in mobile phone wireless charging technology. Although the user experience is not perfect, it has begun to take shape. The convenience brought by mobile phone wireless charging is also the direction of technological progress. It is indeed not an easy thing to say I love you for mobile phone wireless charging now, but I believe it will definitely be a new trend and a new technical stage in the near future.

懒猫爱飞

The main problem is that it is not very convenient. When I play games, I can use a cable to charge while playing (of course it is dangerous), but wireless charging is not possible. I have to put it on the stand.

tiankai001

If the bottleneck is not resolved, development will not be fast.