October 8, 2012 at 14:29How Qi Wireless Universal Chargers Work
As you know, our latest smartphones Nokia Lumia 920 and Nokia Lumia 820 have the ability to wirelessly charge: the flagship model charges by air "out of the box", and for the Lumia 820 you need to purchase a removable case with the ability to wirelessly charge.
Wireless charging devices have already been shown to the world, for example, Touchstone charger for Palm Pre, Powermat for iPhone, induction charging from Energizer. But unlike these chargers, created according to our own specifications, and therefore incompatible with other devices, we use the Qi standard - the only globally accepted wireless charging interface for devices created by the Wireless Power Consortium consortium consisting of more than 100 different companies.
Qi standardDesigned to transfer energy to various devices using magnetic induction. Technically, this is very similar to the solution that is used to charge electric toothbrushes.
In simple words, the base station consists of an induction coil, which creates an electromagnetic field when AC is received. The device that needs to be charged has a similar coil capable of picking up this field, converting the energy received into direct current, which is used to charge the battery.
If we consider the process in more detail, the transmitter (wireless charging transmitter ) consists of a current transducer ( ac-dc power converter ), specifying the devices ( drivers ), the transmitting coil ( transmit coil ), the potential and current sensing ( voltage and current sensing ) and controller ( controller ). Receiver ( receiver) Comprises a coil which receives ( receive coil ), a rectifier ( rectification ), the voltage regulator ( voltage conditioning ) and a controller ( controller ).
Energy is transmitted from the transmitter to the receiver through an interconnected magnetic field that occurs when alternating current flows through the transmitter coil. If the receiver coil is in close proximity, a significant part of the transmitter power lines will pass through the receiver coil, creating an alternating current in the receiver, which is then converted to direct voltage.
You can watch an interactive presentation with a detailed description of the technology on the WPC website .
The energy efficiency of Qi Wireless Chargers is approximately 80%. It should be understood that energy efficiency of 100% is simply impossible to achieve, with standard wired chargers this figure is from 75% to 95% at best.
Regarding the safety of wireless chargers, we can say that we use non-ionizing frequencies that do not have a harmful physiological effect. The Qi 1.1 standard includes the detection of foreign objects in the field of action of the charger, providing additional security for use; Charging is only possible with Qi-compatible devices. Also, our chargers and smartphones have built-in safety mechanisms based on thermal monitoring.
After the publication of the low-power (five watts) Qi specification in August 2009, in 2011 the Wireless Power Consortium began work on expanding the specification to medium power, allowing it to increase power to 120 watts. Despite the fact that the first specification is enough for charging phones, the new Qi standard will be able to provide not only charging smartphones, but also, for example, requiring more power tablets.
Thanks to the Wireless Power Consortium, the wireless charger ecosystem is growing at a very fast pace. So, we entered into agreements with Virgin Atlantic and The Coffee Bean & Tea Leaf, where soon all tables will be equipped with built-in chargers: the phone will be charged simply lying on the table while you drink your coffee. In Russia, we are also negotiating cooperation with various businesses in order to introduce the same tables with wireless chargers in their establishments as soon as possible.
Apart from the main charger - wireless charging pad Nokia - we have wireless charging pillow by Fatboy Nokia , Nokia wireless charging cradle and speaker JBL PowerUpfor Nokia with the wireless charging function, which not only charges your phone according to the Qi standard, but also plays music from it, connecting via NFC - we already wrote about it .
Wireless charging devices have already been shown to the world, for example, Touchstone charger for Palm Pre, Powermat for iPhone, induction charging from Energizer. But unlike these chargers, created according to our own specifications, and therefore incompatible with other devices, we use the Qi standard - the only globally accepted wireless charging interface for devices created by the Wireless Power Consortium consortium consisting of more than 100 different companies.
Qi standardDesigned to transfer energy to various devices using magnetic induction. Technically, this is very similar to the solution that is used to charge electric toothbrushes.
How it works?
In simple words, the base station consists of an induction coil, which creates an electromagnetic field when AC is received. The device that needs to be charged has a similar coil capable of picking up this field, converting the energy received into direct current, which is used to charge the battery.
If we consider the process in more detail, the transmitter (wireless charging transmitter ) consists of a current transducer ( ac-dc power converter ), specifying the devices ( drivers ), the transmitting coil ( transmit coil ), the potential and current sensing ( voltage and current sensing ) and controller ( controller ). Receiver ( receiver) Comprises a coil which receives ( receive coil ), a rectifier ( rectification ), the voltage regulator ( voltage conditioning ) and a controller ( controller ).
Energy is transmitted from the transmitter to the receiver through an interconnected magnetic field that occurs when alternating current flows through the transmitter coil. If the receiver coil is in close proximity, a significant part of the transmitter power lines will pass through the receiver coil, creating an alternating current in the receiver, which is then converted to direct voltage.
You can watch an interactive presentation with a detailed description of the technology on the WPC website .
Interesting details
- The charger may consist of several transmitting coils that are activated depending on the position on the device that needs to be charged.
- The Qi standard supports a data transfer protocol between chargers and rechargeable devices at a speed of 2 kbps. Now, according to this protocol, information about the required level of electricity for a full charge, as well as messages that the device has been charged, is transmitted from the charging device.
Energy efficiency
The energy efficiency of Qi Wireless Chargers is approximately 80%. It should be understood that energy efficiency of 100% is simply impossible to achieve, with standard wired chargers this figure is from 75% to 95% at best.
Security
Regarding the safety of wireless chargers, we can say that we use non-ionizing frequencies that do not have a harmful physiological effect. The Qi 1.1 standard includes the detection of foreign objects in the field of action of the charger, providing additional security for use; Charging is only possible with Qi-compatible devices. Also, our chargers and smartphones have built-in safety mechanisms based on thermal monitoring.
The future of wireless charging
After the publication of the low-power (five watts) Qi specification in August 2009, in 2011 the Wireless Power Consortium began work on expanding the specification to medium power, allowing it to increase power to 120 watts. Despite the fact that the first specification is enough for charging phones, the new Qi standard will be able to provide not only charging smartphones, but also, for example, requiring more power tablets.
Thanks to the Wireless Power Consortium, the wireless charger ecosystem is growing at a very fast pace. So, we entered into agreements with Virgin Atlantic and The Coffee Bean & Tea Leaf, where soon all tables will be equipped with built-in chargers: the phone will be charged simply lying on the table while you drink your coffee. In Russia, we are also negotiating cooperation with various businesses in order to introduce the same tables with wireless chargers in their establishments as soon as possible.
Apart from the main charger - wireless charging pad Nokia - we have wireless charging pillow by Fatboy Nokia , Nokia wireless charging cradle and speaker JBL PowerUpfor Nokia with the wireless charging function, which not only charges your phone according to the Qi standard, but also plays music from it, connecting via NFC - we already wrote about it .