Wireless Charging provides a convenient, safe, and reliable way to charge and power millions of electrical devices at home, in the workplace and in industry.
By eliminating the use of physical connectors and cables, wireless charging provides a number of efficiency, cost and safety advantages over the traditional charging cable.
From smartphones, to hand-held industrial devices and heavy-duty equipment applications, wireless power maintains safe, continuous, and reliable transfer of power to ensure all varieties of devices and equipment are charged and ready to go at a moment’s notice.
- What is wireless charging?
- How does wireless charging work? (+ infographic)
- What is ‘Resonant’ wireless charging?
- The future of wireless charging
- Current and future applications of Wireless Charging
What Is Wireless Charging?
Essentially wireless charging (a.k.a wireless power transfer) uses electromagnetic fields to safely transfer power from a transmitting source to a receiving device for the purposes of charging (or recharging) a battery. And as the name suggests, it does so without the use of a physical connection.
How Does Wireless Charging Work?
Wireless charging is based on the principle of magnetic resonance, or Inductive Power Transfer (IPT). This is the process of transferring an electrical current between two objects through the use of coils to induce an electromagnetic field.
The diagram below simplifies the process of wireless charging and power transfer into 5 key steps.
Transcript of wireless charging steps
- Mains voltage is converted into high frequency alternating current (AC).
- The alternating current (AC) is sent to the transmitter coil by the transmitter circuit. The alternating current then induces a time varying magnetic field in the transmitter coil.
- Alternating current flowing within the transmitter coil induces a magnetic field which extends to the receiver coil (when within a specified distance).
- The magnetic field generates current within the receiver coil of the device. The process whereby energy is transmitted between the transmitter and receiver coil is also referred to as magnetic or resonant coupling and is achieved by both coils resonating at the same frequency.
- Current flowing within the receiver coil is converted into direct current (DC) by the receiver circuit, which can then be used to charge the battery.
It’s through this process that power is safely transferred over an air gap. As well as any non-metal object that might exist between the coils. Such as wood, plastic or granite.
What Is ‘Resonant’ Wireless Charging?
You will often hear people talk about inductive and resonant technology in regards to wireless power. From a technical point of view, they are essentially one in the same. Inductive power transfer (as the overriding principle) uses resonance in order to achieve coupling of the transmitter and recover coil – achieved when the transmitter and receiver coils both oscillate – or ‘resonate’ – at the same frequency. This resonant frequency refers to the frequency at which an object naturally vibrates or rings. This is most commonly seen in the way a tuning fork can cause another to vibrate when both are tuned to the same pitch.
However in recent times, the term ‘resonant’ has taken on a slightly different meaning. What is now commonly referred to as Resonant wireless charging, is seen as an advancement on inductive capabilities in that it allows a number of advantages in relation to performance and convenience.
Some of the key advantages include:
- Greater spatial freedom: This refers to the ability to achieve coupling/power transfer with greater mis-alignment for the receiver and transmitter coil along the x, y and z axis. In a real-life scenario, this means not having to precisely align your smartphone or device on top of the transmitter in order for it to begin charging.
- Charging multiple devices simultaneously: Resonance promises the ability to charging more than one device at a time. How this is achieved from a technical point of view will depend on the coil geometry of the respective system, but nonetheless it provides an added convenience for larger transmitter surfaces such as table tops or work benches.
- Charging speeds: Charging speeds for devices will continue to be a major factor in the adoption of wireless charging. Current inductive charging solutions produce slower charge times compared to a wired charger. In the future, resonant promises improved efficiency for power transfer between the transmitter and receiver coils, which in turn increase the rate at which power is delivered to the battery for re-charging.
For a more in-depth look into the advantages of resonant wireless charging and a discussion on the current options being developed in the marketplace – check out our blog from 2015: What’s the big deal about Resonant?
The Future Of Wireless Charging
No matter the device, industry, or application, the removal of the physical connection required for powering or charging devices delivers a number of benefits over traditional cable connectors – some of which aren’t immediately obvious.
The video below takes a glimpse into the future and examines just some of the possible applications using wireless power.
Current and Future Applications for Wireless Charging
Wireless Charging for Smartphones & Tablets
Perhaps the most well known application of wireless charging is for smartphones.
In recent years, the number of phone manufacturers who have offered wireless charging capabilities have steadily grown, and for even those brands which do not have wireless charging functionality, you can acquire a myriad of external charging cases and sleeves which can enable wireless charging of these devices.
The current technology enables consistent, safe charging of single devices when placed accurately on a charging pad – characteristic of inductive charging systems. The leading standard worldwide for this technology is Qi, which is developed by the Wireless Power Consortium and is used by over 900 products worldwide.
As advancements continue to be made, wireless charging will likely become more ubiquitous and convenient. The development of resonant capabilities will continue to increase the appeal of wireless charging for consumers, while integrated transmitters into tables and bench tops will make it easier than ever to recharge our phones.
PowerbyProxi doesn’t manufacture charging pads or integrated receiver solutions like sleeves and cases for public purchase. Instead our focus is on developing the next generation of solutions for wireless charging for smartphones including greater capability for free placement of devices, foreign object detection and multi-device charging.
Customers have the opportunity to purchase our development kit and patent licenses to develop and manufacture their own product. For more information, check out our Proxi-2D EVK page.
Wireless Charging for Wearables
There is no question that wearable technology is becoming increasingly integrated and available in our daily lives.
The size and form factor of such devices are integral to making them more ubiquitous and convenient from a consumer perspective. At the same time, the miniaturised nature of wearables provide unique challenges around recharging and ensuring power is supplied in a manner that is equally as convenient as the device itself.
Wireless power is potential solution for this problem by removing the requirement for cables and h being connected directly to the device itself.
PowerbyProxi began investigating several means to provide a convenient, cable free solution for recharging multiple wearable devices simultaneously as part of our Proxi-3D project – established within our Proxi Labs innovation centre.
Wireless Charging for AA Battery Powered Devices
Millions of everyday electronic devices – including video game controllers, remotes, torches, toys etc, use AA batteries. However whenever these batteries run out of charge, the means to replace or recharge them, isn’t exactly convenient. Non-rechargeable batteries cost a lot to continually replace, and are a significant biological hazard when disposed of. Rechargeable AA batteries however, can be time consuming and a hassle to recharge, while being that much more expensive.
Wireless power technology offers another solution through in-device charging, whereby AA batteries are fitted with a wireless receiver which can recharge the battery when placed inside a transmitter device. The beauty of this solution is that the battery can be recharged without being removed from the device, so that it never needs to be replaced. PowerbyProxi prototyped a solution for AA batteries as part of our Proxi Labs innovation centre which allowed for safe wireless charging of numerous types of devices using specially designed AA batteries.
Wireless Charging for Commercial Applications
The advantages of wireless charging is not only restricted to consumer device applications. Wireless charging offers real benefits in terms of productivity, efficiency and safety for industrial applications where cables and connectors can become unreliable, dangerous or incur high maintenance costs.
Benefits of Wireless Charging:
- Reduced cost associated with maintaining mechanical connectors. For example: Slip Rings
- Safe powering or charging devices that need to remain sterile or hermetically sealed (waterproof)
- Prevent corrosion due to elements such as oxygen and water
- Eliminate sparks and debris associated with wired contacts
PowerbyProxi have been pioneering the application of inductive power for industrial applications since 2007. Enabling equipment suppliers to deliver mission-critical wireless power systems in wet, dirty and moving environments the world over.
With a range of wireless power transfer solutions for different power requirements, we are able to deliver unique advantages for the transmission of power for a range of applications, some of which are highlighted below:
Medical Devices & Equipment
Wireless Charging Of Medical Devices & Equipment
Wireless charging has a vital role to play in the future of medicine and medical care.
Nowadays, even the most basic of medical procedures requiresa range of advanced medical equipment. Equipment that’s powered largely via battery packs or mains power supplies. Wireless power provides real benefit in such sterile and high traffic environments where traditional connectors become not only source of contamination, but are also a physical hazard as room configurations are constantly changing.
Vehicles & Transport
Wireless Charging Of Electric Vehicles
Wireless charging of electric vehicles continue to be one of the most researched areas of wireless power transfer. By reducing the reliance on fossil fuels, electric vehicles provide a sustainable and environmentally safe means for fuelling our vehicles well into the future.
However today’s electric cars are limited to an average travel distance of between just 10 and 40 miles before they require charging. Initiating a convoluted charging process that requires access to a charging point, charging cables, and a multiple-hour wait before the vehicle is sufficiently charged.
With the introduction of wireless charging, the charging experience is set to become a seamless one. Allowing for the convenient charging of electric cars whether parked or on the move.
It won’t be long before this dream becomes a reality. In fact, a number of car manufacturers are already putting test vehicles through their paces. Including the Formula E’s wirelessly chargeable safety car.
This inclusion of wireless charging capabilities won’t just drive an increased adoption of electric vehicles. It will also play a crucial role in supporting the environmental sustainability of future transport. Helping to rid the environment of harmful fossil fuels, cutting down on air pollution emissions and providing not just a more convenient future, but a healthier one too.
Wireless charging for electric vehicles could be carried out in a number of ways, including:
- Parking Spots & Charging Pads
Like our smartphones and tablets, charging pads will provide one of the most convenient methods of charging electric vehicles. With these pads built into specially designed parking spots, you’ll be able to charge your car while you’re grabbing your shopping or catching a movie.
- Electrically Charged Highways Of The Future
In time, you may not even need to stop to charge your electric car. Highway England is just one body currently testing the viability of charging lanes that charge vehicles while they’re driving. With the charging devices built into the very asphalt itself.
IS THERE A WIRELESS CHARGING STANDARD?
An industry standard is required to ensure interoperability between transmitters and receivers made by different manufacturers. There are currently two key groups looking to put forward a specification for wireless charging: the Wireless Power Consortium (WPC) and the Airfuel Alliance.
Of these two, the Wireless Power Consortium is the leading standard for wireless charging through its Qi standard. Qi (pronounced ‘chee’) is the most widely used and commercially available wireless charging standard (used by over 200 companies). The Qi standard ensures that any device carrying its logo will work, in turn, with any charging surface that also carries the logo, regardless of brand or manufacturer.
This cross-compatibility allows manufacturers like PowerByProxi complete design freedom, as the Qi standard ensures that wireless charging interoperability is guaranteed from conception through to completion. This page on wireless power standards provides further information.
WHY DO WE NEED A STANDARD & WHAT WILL IT GOVERN?
Industry standards are crucial to ensuring interoperability between transmitters and receivers produced by different manufacturers. Once a specification emerges as the standard for the industry, then manufacturers have a blueprint from which to work to create wireless charging technology in the future, thus ensuring that no matter what the device, it can be charged on any charging pad or transmitter.