How Does Wireless Charging Work?

2018-03-23

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Wireless charging will become more and more popular after Apple’s iPhone 8  iPhone 8 Plus and iPhone x use Qi wireless charging technology. It can also be seen on some Android phones, such as Samsung's Galaxy Note 8, Galaxy S8 and Galaxy S7.

Most of the wireless chargers use magnetic induction and magnetic resonance, which ensure that the device on a surface will automatically charge without any cable. 

How Does wireless charging  Work?


Of course, wireless charging is not really wireless charging. Your mobile phone, smartwatch, tablet, wireless earphone or other devices don’t need to be wired into the charger, but the wireless charger needs to be plugged into a socket to work. 


Apple's Phil Schiller said that when the iPhone 5 was released without wireless charging, Apple's Phil Schiller said, "in most cases, having to develop another device is actually more complicated. "


Five years later, Apple changed its mind. With the support of iPhone 8, iPhone 8 Plus and iPhone X, Apple supports wireless charging using the Qi open standard.

Wireless chargers usually use magnetic induction. Generally speaking, they use magnetism to transfer energy. First, you put your phone on a wireless charger, like a smartphone. 


The current from the wall power outlet creates a magnetic field through the wire of the wireless charger. The magnetic field generates current inside the coil on the wireless charger. This magnetic property is converted into electricity, which is used to charge the battery. 


The device must have the right hardware to support wireless charging-a device. Although the Qi standard was initially limited to magnetic induction, it now also supports magnetic resonance.

what is qi wireless charging


It can be located 45 millimeters from the surface of the wireless charger, rather than touching it directly.


This approach is less than magnetic induction, but it also has some advantages. for example, a wireless charger can be installed under the surface of a table, and you can put a device on the table to recharge.


It also allows you to put multiple devices on one rechargeable panel and charge all devices at the same time. The Qi charger does not consume the maximum power when it is not actively charged. Instead, it uses less power, and when it detects that the device is placed on the charger, it increases the output of energy.

Wireless Charging Technology


There are five kinds of wireless charging standards, such as, Qi standard, Power Matters alliance standard, Alliance for Wireless PowerPoint A4WP standard, iNPOFi technology, Wi-Po technology.

1.Qi standard

Qi is the world's first standardized organization to promote Wireless Power Consortium, with convenience and versatility. First, different brands, as long as they have a Qi logo, can be recharged with Qi wireless chargers. Secondly, it has overcome the technical bottleneck of "versatility" of wireless charging. In the near future, mobile phones, cameras, computers, and other products can be charged with Qi wireless chargers, providing the possibility for large-scale applications of wireless charging.

There are three ways of wireless charging technology on the market, electromagnetic induction, radio waves and resonance, while Qi adopted the most mainstream electromagnetic induction technology. In terms of technology applications, Chinese companies are already at the forefront of the wireless charging industry. It is reported that the main application product of Qi in China is mobile phones, which is the first stage, and will be used in different types of digital products or higher power products in the future.

2.Power Matters Alliance Standard

The Power Matters Alliance standard was launched by Duracell Powermat, which is a joint venture between P & G and Powermat, with a strong overall strength. In addition, Powermat is one of the supporting members of the Alliance for Wireless PowerPoint (A4WP).

AT&T, Google and Starbucks have joined the PMA. The PMA is committed to creating wireless power standards for mobile phones and electronic devices that meet the IEEE Association's standards and is a leader in the field of wireless charging.

Duracell Powermat has introduced a WiCC charging card that uses the Power Matters Alliance. The WiCC is larger than the SD card and embedded in components such as coils and electrodes for electromagnetic induction non-contact charging. The card is thinner and can be used to an existing smartphone battery. 

3、A4WP Standard

A4WP( Alliance for Wireless Power) is created by the wireless charging alliance of Qualcomm, Samsung and Powermat. The alliance also includes members such as Ever Win Industries, Gill Industries, Peiker Acustic and SK Telecom and others.  They aim to establish technical standards and industry dialogue mechanisms for wireless charging devices for electronic products, including portable electronics and electric vehicles.


4、iNPOFi Standard

iNPOFi (invisible power field) wireless charging is a new wireless charging technology. Its series products are equipped with intelligent electric transmission wireless charging technology, with no radiation, high power conversion efficiency, weak thermal effect and other characteristics.

Compared with other existing wireless charging technologies, iNPOFi does not produce any radiation. The test results of China Taierl Laboratory show that the increase value of radiation is near zero. In terms of efficiency, Taier Laboratory also determined that charging transmission efficiency is up to 90%, completely solving the problem of the traditional wireless charging less than 70%conversion efficiency.

In the aspect of intelligent management, chip adaptation management technology includes automatic opening and closing charging process, automatic adaptation manages voltage and current required to ensure higher charging efficiency. And a unified charging boar provides safe, convenient and efficient charging for any brand , model products. 

In the aspect of safety, we also take into account the security problems in various kinds of weak charge, such as electrostatic ESD protection, anti-overcharge, anti-shock and so on, even if the power management of the equipment itself has problems,electronic devices can be automatically fused through inpofi chips to protect them from damage.

It is worth mentioning that a Inpofi used a small chip as a core has been designed to be ultramicroscopic, only one fourth of 50 cents so it can be easily integrated into any device and integrated into various forms of wearable devices. This is beyond traditional electromagnetic products.

As a new generation wireless charging technology standard, iNPOFi technology is efficient, green, convenient and economical. This charging device is often used in the power transmitting device and the power receiving device. The size and thickness of the transmitting device are the same as the ordinary mobile phone, and the receiving device is embedded in the mobile phone protection case, and the mobile phone cover is placed in the protective case. Put your phone on surface to charge.  During charging, the phone does not need to plug in any cable. 

Related tests show that there is not any the electromagnetic radiation in the charging process, power efficiency conversion reached 94.7%, closing to wired charging. Charging equipment not only supports low voltage power supply and is compatible with ordinary USB power supply but also  realizes low temperature charging, which effectively ensures the safety and lifetime of equipment and battery.

5.Wi-Po Technology

Wi-Po technology that is a Wi-Po magnetic resonance wireless charging technology uses a high frequency constant amplitude alternating magnetic field generator to generate a 6.78 MHz magnetic field and achieve a longer emission distance.

This technology can realize communication through Bluetooth 4.0,and can support one-to-many synchronous communication,which is safe and reliable. It also detect over-temperature, overvoltage, over-current protection and other foreign matters. Because the carrier used in this technology is a space magnetic field, energy will not be emitted like electromagnetic waves, so it will not cause radiation damage to the human body.

Wi-Po can be used in mobile phones, computers, smart wear, smart home, medical devices, electric vehicles and other scenarios.


Competition standard: Qivs Powermat vs Rezence


Wireless charging is becoming more common and even more standardized. But on this occasion,  Apple has not made their own wireless standards. Instead, it has supported the existing Qi standard, which is also supported by many other devices.

However, Qi is not the only standard. The Wireless Power Alliance has a leading Qi standard, but it is not the only one. In second place was Powermats, or PMA, of the Power transaction Coalition. It uses magnetic induction, like Qi.

However, the two are incompatible. IPhone cannot be charged with PMA wireless charger. However, some devices are compatible with both.

Modern Samsung devices, such as the Samsung Galaxy Note 8, Galaxy S8 and Galaxy S7, actually support Qi and PMA standards and can be recharged at the same time.

Starbucks restarted to considered Qi, no longer PMA. Apple will also choose Qi at airports, hotels and other public places. A4WP used magnetic resonance and later added a feature that makes positioning freer.

You can install multiple devices on one charger. Rezence also requires Bluetooth to communicate with the device.

As the second and third ranked company, the team built by the Power Affairs Alliance and the Wireless Power Alliance have been renamed the "Air fuel Alliance" and are trying to work together with Qi. 


Advantages and disadvantages of the wireless charging 



Advantages:

1.The equipment with wireless magnetoelectric induction charging can be invisible, the equipment wear rate is low, the application range is wide, the area of public charging area is relatively reduced, but the decrease of the occupied area is not too large.


2. convenience. Charging without wire connection, as long as the charger can be placed near, do not need to occupy a plurality of power outlets, there is no trouble with multiple wires winding each other.


3. Convenient operation

Disadvantages:

1.Because of the high technology and high cost, the maintenance cost is high.


2.Because of the realization of long-distance high-power transportation, so the energy consumption of the device is high, with the increase of the distance and power of wireless charging equipment, the loss of useless power will be greater.


3.Wireless charging realizes the secondary energy conversion. Because the conversion of high power AC-DC current is the reason for the secondary wireless transmission of electric energy, it lose a lot of electromagnetic field.


How do we use the wireless charging?


If you want wireless charging, you need a smartphone that supports wireless charging and a compatible wireless charging pad where your phone is placed on. You also can buy adapters to charge your phone that don’t include them.

In recent years, Android handset makers have increasingly abandoned wireless charging technology. Only Samsung has maintained this feature on its latest high-end phone.Wireless charging may become more common on Android devices, because Apple's voted for Qi technology.

If your phone does not support wireless charging, you can add wireless charging support through a special phone case or wireless charging adapter.

Once you have a phone or adapter that supports wireless charging, only need a compatible wireless charger. Any Qi certified wireless charger should be compatible with any Qi authentication device. As long as your device and charger support the same standard, it will work.


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