IEC TR 63231-2019 pdf free.Consideration of energy efficiency in wireless power transfer technology.
4.2Magnetic induction wPT systems
An alternating electric current flowing through a coil (source) generates a magnetic field thatacts on a receiver coil to produce a current within it, and thus electric power is transferredbetween the source and device-to-be-charged (DTBC) coils.
Tight magnetic coupling between the two coils helps achieve high transfer efficiency.Becausethe electric power transfer distance is short, typically measured in the mm range, the wPT bythe electromagnetic induction is often called noncontact power transfer, or tightly-coupled wPT.
4.3 Magnetic resonance is a special case of electromagnetic induction where resonant coils areused such that higher efficiencies can be supported for a given coupling factor (k) inconfigurations designed for low (much less than 1,0) coupling factor. The magnetic resonancemethod utilizes a source consisting of a coil and series capacitor as a resonator，with acorresponding sink element consisting also of a coil and series capacitor as a tuned resonator.Electric power is transferred through the electromagnetic resonance between the source andDTBC coils.By matching the resonance frequency of the source coil and the DTBC coil in ahigh Q factor regime, electric power is transferred over a long distance (mm to m) even wheremagnetic coupling (k) between two coils is low.
The magnetic resonance approach is referred to interchangeably as magnetic resonant coupling.highly resonant magnetic induction, or loosely coupled WPT.
4.4Microwave (RF) used in wPT systems
Power transfer via radio waves can be made more directional, allowing longer-distance powerbeaming，with shorter wavelengths of electromagnetic radiation，typically in the microwaverange.
Power beaming by microwaves has the difficulty that, for most space applications, the requiredaperture sizes are very large owing to diffraction limiting antenna directionality.
In 2013，inventor Hatem Zeine demonstrated how wireless power transmission using phasedarray antennas can deliver electrical power up to 30 feet away. lt uses the same radiofrequencies as Wi-Fi.
IEC TR 63231  In 2015, researchers at the University of Washington introduced power over Wi-Fi, which trickle-charges batteries and powered battery-free cameras and temperature sensors usingtransmissions from Wi-Fi routers. Wi-Fi signals were shown to power battery-free temperatureand camera sensors at ranges of up to 20 feet. lt was also shown that Wi-Fi can be used towirelessly trickle-charge nickel-metal hydride and lithium-ion coin-cell batteries at distances ofup to 28 feet.
4.5Capacitive wireless power transfer (CPT)
Research efforts are being published in capacitive WPT, which uses an electric field to transferpower (in contrast with the magnetic field in 4.2 and 4.3, or coupled electro-magnetic fields in4.4).
5 wPT product use cases
5.1General
In order to consider energy efficiency measurements in WPT, the current scope of commerciallyavailable products needs to be explored.The products described in this clause are presentedas use cases for energy efficiency considerations. A typical configuration of a commerciallyavailable system consists of a transmission or charging pad and a device with a receiver.
5.2.1 Smartphones
Most high-end smartphones available commercially have wireless charging capability.Smartphones are the current leader in today’s market with regard to wireless power transferfunctionality
5.2.2 Smartwatches
Some smartwatches have wireless power functionality, even though the current market is small.5.2.3Laptops
While there are a few laptop models with wireless power transfer charging capability, this marketis small. Most laptops do not have this capability.
5.3 Transmitters
5.3.1Vertical figure product
Vertical charging pads are the most popular product in the wireless power transfer market ofcommercially available products (see Figure 1).IEC TR 63231 pdf download.