Wireless charging technology (wireless schargetchnology) originated from wireless power transmission technology, which can be divided into low-power wireless charging and high-power wireless charging.
Low power wireless charging often adopts electromagnetic induction, such as Qi charging for mobile phones, but ZTE's electric vehicle wireless charging mode adopts inductive charging [1]. High power wireless charging usually adopts resonant mode (which is adopted in most electric vehicle charging). The power supply equipment (charger) transmits the energy to the electric device. The device uses the received energy to charge the battery and supply it for its own operation at the same time.
Since the energy is transmitted by magnetic field between the charger and the electrical device, there is no wire connection between the two, so the charger and the electrical device can achieve no exposed conductive contact.
There are five mainstream wireless charging standards: Qi standard, powermatters Alliance (PMA) standard, Alliance for wireless power (a4wp) standard, inpofi technology and wi Po technology.
1. Qi standard
Qi is the world's first standardization organization to promote wireless charging technology Wireless Power Consortium (WPC) launched the "wireless charging" standard, with two major characteristics of convenience and versatility. First of all, products of different brands can be charged with Qi wireless charger as long as they have a Qi logo. Secondly, it has overcome the technical bottleneck of "universality" of wireless charging. In the near future, mobile phones, cameras, computers and other products can be charged with Qi wireless charger, providing the possibility for large-scale application of wireless charging.
The mainstream wireless charging technology in the market is mainly through three ways, namely electromagnetic induction, radio wave and resonance. Qi adopts the most mainstream electromagnetic induction technology. In terms of technology application, Chinese companies have been at the forefront of the wireless charging industry. It is reported that Qi's application products in China are mainly mobile phones, which is the first stage, and will be developed and applied to different categories or higher power digital products in the future.
2. Powermatters alliance standard
The standard of powermatters alliance is initiated by Duracell Powermat, which is a joint venture between P & G and Powermat, a wireless charging technology company, with excellent comprehensive strength. In addition, Powermat is a supporting member of the Alliance for wireless power (a4wp) standard.
At & T, Google and Starbucks have joined the PMA alliance. PMA alliance is committed to building wireless power supply standards for mobile phones and electronic devices that meet IEEE standards, and has a leading position in the field of wireless charging.
Duracell Powermat introduced a wicc charging card based on the powermatters alliance standard. Wicc is one circle larger than SD card, and has embedded coil and electrode components for electromagnetic induction non-contact charging. The thickness of the card is relatively thin. It can be used by inserting it next to the battery of existing smart phones. With this card, many portable terminals can easily support Contactless charging.
3. A4wp standard
A4wp is the abbreviation of alliance for wireless power standard. It is created by the wireless charging alliance jointly established by Qualcomm, Samsung and Powermat. The alliance also includes Everwin industries, gillindustries, peikeracustic and sktelecom. Its goal is to establish technical standards and industry dialogue mechanisms for wireless charging devices for electronic products, including portable electronic products and electric vehicles.
4. Inpofi Technology
Inpofi (invisible power field) wireless charging is a new wireless charging technology. Its wireless charging series products adopt intelligent electric transmission wireless charging technology, with the characteristics of non radiation, high power conversion efficiency, weak thermal effect, etc.
Compared with other existing wireless charging technologies, inpofi has no radiation, adopts electric field pulse mode, and does not generate any radiation. The test results of China Tel laboratory show that the added value of radiation is almost zero. In terms of high efficiency, Theil laboratory also determined that the charging transmission efficiency of the products of this technology is as high as 90%, which completely changes the low efficiency of traditional wireless charging up to 70%.
In terms of intelligent management, chip adaptation management technology is adopted, including: automatic opening and closing of charging process; automatic adaptation of required voltage and current to manage charging process to ensure high charging efficiency; and a unified charging board can be used to charge any brand and model of electronic products safely, conveniently and efficiently. In terms of safety, it also takes into account various safety problems in weak current charging, such as electrostatic ESD protection, overcharge prevention, impact protection, etc. even if the power management of the receiving equipment is in trouble, the inpofi chip can automatically fuse to protect the electronic equipment from being damaged.
It is worth mentioning that for intelligent device manufacturers, inpofi has realized ultra micro design with a tiny chip as its core. It is only 1 / 4 of the size of a nickel coin. It can be easily integrated into any device, and can also be integrated into various forms of wearable devices. This is the traditional electromagnetic principle of products can not achieve.
IOFI, as a new generation of wireless charging technology, is an economic and efficient technology. The charging equipment using this technology consists of two parts: power transmitter and power receiver. The size and thickness of the transmitter are similar to those of ordinary mobile phones, and the receiving device is embedded in the hand
