Wireless Charging Technology : The Fuel of Future

Introduction:

In this article, we will discuss Wireless charging Technology eliminates the requirement of charging cables and allows charging of multiple devices in parallel. There are no charging cable incompatibility issues. Basically, wireless charging works on the principle of electromagnetic induction: Time-varying magnetic field induces a current in a closed loop of wire to transfer power from the transmitter to the receiver without requiring a physical connection.

Wireless Charging Technology allows auto shutdown when charging is complete. As it does not require mechanical connectors, the manufacturing cost is less. Embedding this technology in mobiles will allow mobile manufacturers to do away with power supply sockets, which allow entry to water, dust, and other corrosive materials.

How Wireless Charging Technology Works?

Wireless charging Technology also is known as Inductive charging or cordless charging uses an electromagnetic field to transfer energy between two objects through electromagnetic induction. This is usually done with a charging station. Energy is sent through an inductive coupling to an electrical device, which can then use that energy to charge batteries or run the device.

Induction chargers use an induction coil to create an alternating electromagnetic field from within a charging base, and a second induction coil in the portable device takes power from the electromagnetic field and converts it back into electric current to charge the battery. The two induction coils in proximity combine to form an electrical transformer. Greater distances between sender and receiver coils can be achieved when the inductive charging system uses resonant inductive coupling.

Applications Areas

Applications of inductive charging can be divided into two broad categories: Low power and high power:

1. Low power applications are generally supportive of small consumer electronic devices such as cell phones, handheld devices, some computers, and similar devices which normally charge at power levels below 100 watts.

2. High power inductive charging generally refers to the inductive charging of batteries at power levels above 1 kilowatt. The most prominent application area for high power inductive charging is in support of electric vehicles, where inductive charging provides an automated and cordless alternative to plug-in charging. Power levels of these devices can range from approximately 1 kilowatt to 300 kilowatts or higher. All high power inductive charging systems use resonated primary and secondary coils.

Advantages:

1. Protected connections, so no chances of corrosion
2. Low infection risk for embedded medical devices
3. Durability is no need to constantly plug & unplug the device preventing wear & tear
4. Increased convenience and aesthetic quality as no need for cable
5. Inductive charging systems can be operated automatically resulting in higher reliability.

Disadvantages:

1. Slower charging
2. More expensive
3. Inconvenience as device can’t be moved while charging
4. Compatible standards with individual devices
5. Inefficiency

Wireless charging technology – The Qi standard:

The Qi (pronounced chee) standard was developed in 2010 by the Wireless Power Consortium in which over 320 companies (including Philips, Sanyo, Panasonic, Nokia, Samsung, Sony Ericsson, LG, HTC, and Motorola) participate. Qi is the sign of interoperability between power transmitters and power receivers. A vastly growing number of devices such as smartphones, cameras, speakers, and wearables have Qi technology incorporated as a standard. All Qi receivers will work with all Qi transmitters, meaning that all enabled devices are compatible.

Qi is derived from Asian philosophy. It means ‘vital energy’, an intangible flow of power. When this logo is on your portable device, it can be charged with any ZENS Wireless Charger.

Design tips for engineers:

1. To overcome wireless charging issues like low efficiency, heat dissipation, cost and short-distance transmission, manufacturers need semiconductor solutions. Efficient and easy-to-design transmitter solutions top the list.

1. Smart heat management keeps the transmitter and surface at the working temperature range, keeping the device battery from heating during charging. The design should be compact and easy to carry. Faster charging speed can be achieved by lowering switching and conduction losses.

2. In place of GaN, Infineon uses mature and reliable silicon technology to achieve high performance. It is currently working on boosting the performance further with medium-voltage GaN solutions that have the same maturity level as silicon devices.

3. Vinay, a sales representative from Mouser, informs that their solutions utilize inductive charging and that they have further reduced the leakage field by providing an EMI shield at the back of the coil to achieve an efficiency of up to 93 percent.