The Evolving world of wireless charging technology

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2016-11-28 14:40

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Edited by Aswin_S at 2016-11-28 12:10

                                              When first mobile phone came, it did not even contain camera. But now a day, a phone without camera is considered outdated or less used. Youngsters these days can’t imagine a phone without a touch screen,internet connection and a zillion apps. Technology is growing so fast that it is possible by the time you complete reading this article, they will be thought of as outdated. To avoid this happening, I will move right on to the main topic, and say a few words about wireless charging technology in general.
                                               Nikola Tesla described a device which can transmit power to distant in early 19th century. But he could not experiment on it much as he had engineering and financial limitations.Later on cables became means of transporting electricity. But with wide spread adoption of small, portable devices with batteries in need of constant recharging, people’s attention is again turning to wireless power.
Technology behind wireless charging
                                                Even though Power through radio waves at first seemed promising, later it was found to provide less efficiency. So Companies are relying up on another technology called resonant wireless charging.  Resonant wireless charging - There are mainly two types of wireless charging: inductive and conductive. Inductive charging involves an electromagnetic field to transfer charge across a gap and into the device’s battery. Requisite for inductive charging is an induction coil, which is capable of receiving wireless energy. Conductive charging functions through direct electrical contact between the power source and the battery. Wireless charging or inductive charging uses an electromagnetic field to transfer energy between two objects.                                                 Wireless charging is based on the principle of magnetic resonance or inductive power transfer, the process whereby electricity is transferred between two objects through coils using the following key steps:
1. Mains voltage is converted into high-frequency AC.
2. This is sent to the transmitter coil by the transmitter circuit. It then induces a time-varying magnetic field in the transmitter coil.
3. The AC flowing within the transmitter coil induces a magnetic field that extends to the receiver coil (when within a specified distance).
4. The magnetic field generates current within the receiver coil of the device. The process whereby energy is transmitted between the transmitter and the receiver coil is also referred to as magnetic or resonant coupling, and is achieved by both the coils resonating at the same frequency.
5. This current flowing within the receiver coil is converted into DC by the receiver circuit, which can then be used to charge the battery.
                                                                              
                                                                     
                                                      
                                                  The two coils will form an electrical transformer, when placed in proximity. Through this process, power can be transferred safely over an air gap and also through any non-metallic object that might exist between the coils, such as wood, plastic or granite. Addition of extra (or larger)transmitter coils can also extend the range at which power can be transferred.This is the safest and most-efficient wireless charging technology for electronic devices like Smartphone, phablets and tablets, enabling simultaneous wireless charging of multiple devices, with full spatial freedom for placement of devices in any position (no exact alignment).
                                                                  

                                                           
                                                     
                                                   Companies are also developing a technology that could draw enough power from ambient radio waves to keep a mobile phone handset topped up. Ambient electromagnetic radiation—emitted from Wi-Fi transmitters, mobile phone antennae, TV masts and other sources—could be converted into enough electrical current to keep a battery topped up. They are working towards a prototype that could harvest up to 50 milliwatts of power—enough to slowly recharge a phone that is switched off. Current prototypes can harvest three to five milliwatts.
Qi and PMA
                                                       Even though there are many standards in wireless technology, two of them which are dominating the list and competing are Qi (pronounced as chee)and PMA.




                          Qi (proposed in 2008) is an open interface standard developed by the Wireless Power Consortium(WPC) for inductive charging over distances of up to 4 cm (1.6 inches). The system uses a charging pad and a compatible device, which is placed on top ofthe pad, charging via resonant inductive coupling. HTC, Huawei, LG Electronics, Motorola Mobility, Nokia, Samsung, BlackBerry, and Sony are working on these standards. According to a list of Qi devices by Qi Wireless Charging, July 14, 2016 there were over 140 smartphones, tablets and other devices which can be charged wirelessly with Qi.


                                Power Matters Alliance (PMA) is a global,not-for-profit, industry organization whose mission is to advance a suite of standards and protocols for wireless power transfer. Founded by Procter & Gamble and Powermat Technologies in March 2012, PMA is networking technology companies in order to guarantee consumers inter-operable devices which employ wireless power technology. This also works on the Resonant wireless charging. The PMA board of directors includes representatives from AT&T, Duracell, Starbucks, Powermat Technologies, Flextronics, Federal Communications Commission (FCC), and EnergyStar. The membership of the PMA is made up of companies across the mobile device ecosystem, including handset providers, service providers, chip set suppliers, manufacturers, test labs and public establishments.


                                                                                                                    
                                                   But each standards does not support each other thereby making a device which works with a standard will make it unable to charge it by the other. The wireless charging industry is becoming bigger and bigger each year, and it is estimated that this market will be worth $13.7 billion by year 2020.Starbucks has partnered with Duracell to provide its customers with Powermat wireless charging alongside fantastic coffee. IKEA,which has set a new line of furniture that has integrated wireless chargers of Qi technology. There are a few phones that support both standards. Even though this marketing move (alliance with other big companies)sounds like a great move, it is hard to imagine dominance of PMA over Qi, but what is more likely is that we are going to see new smartphones that support both standards, thus offering “everything” to its consumers. Here are some Smartphones which supports wireless charging:

6.AT&T Lg G3
Wireless charging standard: PMA


5. Motorola Droid Turbo
Wireless charging standard: Qi



4. Google Nexus 6
Wireless charging standard: Qi
                       


3. Samsung Galaxy S6 Active
Wireless charging standard: both PMA and Qi



2. Samsung Galaxy S6
Wireless charging standard: both PMA and Qi


1. Samsung Galaxy S6 Edge
Wireless charging standard: both PMA and Qi






Benefits of Wireless charging
                                                                  Whatever the application, removal of the physical connection delivers a number of benefits over traditional cable connections, some of which are not always obvious. Here are some benefits and advantages of resonant wireless charging and offers an insight into a world where wireless power is widely integrated into the home, office and everyday lives:
1. From an environmental standpoint, wireless charging could be incredibly promising. It would eliminate the need for plastic-body chargers, which not only drain power but are also replaced regularly. Wireless charging could save tens of thousands of tons of chargers from ending up in landfills and allow users to tap into existing electronic activity instead of traditional power sources.
2. It provides greater convenience and ubiquity for charging of everyday devices.
3. It would reduce costs associated with maintaining mechanical connectors.
4. It would allow safe powering or charging of devices that need to remain sterile or hermetically-sealed (waterproof).
5. It would eliminate sparks and debris associated with wired contacts.
6. It would provide protected connections; no corrosion when electronics are all enclosed, away from water or oxygen in the atmosphere.
7. It is safer for medical implants (embedded medical devices).It allows recharging/powering through skin rather than having wires penetrate the skin, which increases the risk of infection.
8. It is durable. Without the need to constantly plug and unplug devices, there is significantly less wear and tear on the sockets of the devices and the attaching cables.
9. It enables non-radiative energy transfer.
Disadvantages
                Some disadvantages of wireless charging are:
                                             Lower efficiency and much heat will be generated.Main disadvantages of inductive charging are its lower efficiency and increased resistive heating in comparison to direct contact. Wireless charging is around 60 per cent to 70 per cent efficient, and it is still recommend that booting a device from cold is done through a wired connection. Due to lower efficiency,devices can take longer to charge when supplied similar power. Inductive charging also requires drive electronics and coils in both device and charger,increasing complexity and cost of manufacturing. Whether or not it incorporates resonance, induction generally sends power over relatively short distances.
Safety concerns
                                             There will be safety issues, real or imagined, as all power has to pass through space in some form or the other, and pass through any bodies lying in its path. However, researchers have minimized this problem by ensuring that power is mainly in the form of a magnetic field. It is a form of energy to which the body is almost entirely insensitive. It is believed that wireless charging is safe, even for people with implanted medical devices such as pacemakers.
Future
1. Use ultra thin coils to build the transmitter and receiver which will increase the efficiency.
2. It is worth noting that the lithium-ion chemistry used in smartphone batteries happily copes with having short bursts of energy to charge these up. This is exactly what wireless charging can provide.
3. Future plans for wireless power involve moving electricity over a span of kilometers. A few proposals even involve sending power to the Earth from space.

     I hope this article was informative and useful for you. Now, the question is,
Do you want wireless charging technology in upcoming Meizu Smartphones? Comment your views.