Wireless charging technology

Charging technology Wireless (charge technology Wireless). Wireless

charging technology, from wireless power transmission technology.

Wireless charging, also known as inductive charging, contactless

inductive charging, is the use of the near field induction, which is the

inductive coupling, by the power supply equipment (charger) to transmit

power to the device, the device uses the received energy to charge the

battery, and at the same time for its own use. Since the charger and the

electric device to transmit the energy between the inductor, the two do

not need to wire connection, so the charger and the device can be used

to do without conductive contact. [1]

Summary

Massachusetts Institute of Technology research team published their

findings in the June 7, 2007 American Journal of science. The research

group successfully "caught" the electromagnetic wave with the use of

resonance in the transmission of electromagnetic waves. They use copper

coil as the electromagnetic resonator, a coil attached to the transmission

power, another group in an electric power. When the transmitting side

sends out a specific frequency electromagnetic wave, after the

electromagnetic field spread to the receiving party, electric power has

realized the wireless transmission. This is known as the "wireless power"

of the technology after many tests, has been able to successfully for a two

meters outside the 60 watt light bulb. The most far transmission distance

of the technology can only reach 2.7 meters, but the researchers believe

that the power supply has been in this range for the battery charge. And

only need to install a power supply, it can be for the whole house of

electrical power.

Resonance principle.

The scientific research group at the Massachusetts Institute of

Technology is not the first to propose the organization of wireless energy

conversion. In nineteenth Century, scientists discovered the phenomenon

of electromagnetic conversion, in theory, power can be converted into

electromagnetic waves through the invisible medium, to achieve the

power of wireless transmission. But electromagnetic wave radiation in all

directions, a lot of energy is lost, so "wireless transmission" research has

made little progress, physicists and engineers in the 19th century Nikola

Tesla were remote wireless energy conversion system experiment, but

when his resources exhausted and the most have ambitious attempt (29

meters high Vaden Cleave Kobita) failed. Other attempt to include laser

and other directional energy conversion mechanism. However, they are

different from the work of Massachusetts Institute of Technology, these

are the need for continuous visual line, which is not good for the power

facilities around the house.2

Wireless charging technology to two mobile phone wireless charging [2]

Research group members, assistant professor Marin Soyak and his

research team are improving the facility. "This is a system that has not yet

been developed, which proves that the energy conversion works. But you

won't be willing to use it to give your laptop power. Our goal is to reduce

the size of the device, expand the distance between sensors and improve

the efficiency of power conversion." He and colleagues Andre Cools, alite

diz, Mr Kalaris, Robert Mohete, John cannon Poluosi and Peter Solico

cooperation, this study.

This system uses the principle of resonance (when an object is the same

as the natural frequency of the other body). When the vibration frequency

of the two bodies is the same, the intensity of the transmitted energy will

not be affected by the surrounding objects. Soyak explained: "if you put a

lot of the same in the room, you pour a different degree of wine into the

bottle, then these cups will produce different amplitude." For example, if

you tap with a spoon, each cup will make a different sound. "If I enter the

room, start with a very high sound, and when my voice is the same as one

of the cups, it is likely to explode."

According to Broadcasting British Corporation in June 19, 2007, the

wireless power transmission is not like the power plant, it can avoid the

damage of the rat nest, reduce a lot of trouble, because it does not need

wire connection. The researchers introduced the device in the science

journal. In an experimental test, the device makes a 80 watt light bulb 2

meters (7 feet) from the lamp. The device is called WiTricity, which is

developed according to the principle of physics, which is also suitable for

providing power to the laptop and other devices. WiTricity uses a low

frequency electromagnetic wave, rather than an acoustic resonance. In

the experiment, the two sensors are vibrating at a frequency of 10 MHz,

resulting in a resonance, allowing energy to pass between the two. "With

each resonance, there will be more voltage generated in the sensor,"

explains John Bendle, a professor at the Imperial College London." After

multiple resonances, the sensor surface will gather enough energy to

make the light shine. The gathering of this energy is the reason why a

singer is singing with the same frequency as the cup, the cup will not

break at once. Bendelai professor said: "wine continues to gather energy,

until their break."

According to Bendelai professor said, using a wavelength of 30 meters

(100 feet) of the low frequency electromagnetic wave has the advantage

of safety. He said: "it is usually used in the mobile phone with a thousand

Hertz (shorter wavelength), the electric field and the magnetic field

radiation at the same time." This process is a typical feature of the "far

field" we know. This field is generated from a device that is more than a

wavelength. If the amplitude is less than a wavelength, the main magnetic

field is generated. John said: "the body's reaction to the electric field is

very strong, which is why you can use the microwave oven to cook

chicken. But the magnetic field does not affect the human body.

According to the body's absorption of energy, the reaction to the

magnetic field is almost zero." Therefore, this device can not bring any

significant health risks to humans.

Mainstream technology

Until now, there are three main types of wireless charging standards: Qi

standards, Matters Alliance Power (PMA), for Wireless Power Alliance

(A4WP) standards, iNPOFi technology. Here are three criteria for the

simple introduction.

1, Qi standard

Qi is the world's first Power Consortium WPC, which promotes the

standardization of wireless charging technology. Wireless charging

sample

The "wireless charging" standard, with convenience and versatility of the

two major characteristics. First, different brands of products, as long as

there is a Qi logo, you can use Qi wireless charger charging. Secondly, it

overcomes the wireless charging "universal" technology bottlenecks, in

the near future, mobile phones, cameras, computers and other products

can be used to charge the Qi wireless charger for wireless charging

large-scale applications.

The mainstream wireless charging technology market is mainly through

three ways, namely, electromagnetic induction, radio waves, and

resonance, and Qi used the most mainstream of the electromagnetic

induction technology. In the technology application, the China Company

has stood at the forefront of wireless charging industry. It is reported that

the application of Qi products in China is the main mobile phone, which is

the first stage, after the development of different types of digital products

will be used to different categories.

2, Matters Alliance Power standard

Matters Alliance Power standard is sponsored by the Powermat Duracell

company, and the company is a joint venture between P & G and wireless

charging technology company Powermat, has a relatively good

comprehensive strength. In addition, Alliance is a member of the for

Wireless Power Powermat (A4WP) standard.

AT&T, Google and Starbucks three companies have joined the PMA

Alliance Power (Matters). The PMA alliance is committed to creating a

wireless power supply standard for mobile and electronic devices, which

are in line with the IEEE standards, and has a leading position in the field

of wireless charging.

Powermat Duracell company launched a WiCC charging card is used in

the Matters Alliance Power standard. WiCC larger than the SD card, the

internal embedded in the electromagnetic induction type contactless

charging of the coil and the electrode and other components, the

thickness of the card is thin, insert the existing smart phone battery can

be used, the use of the card can make a lot of portable terminal easily

support non contact charging.

3, A4WP standard

A4WP is for Wireless Power Alliance standard for short, by the United

States Qualcomm Corp, South Korea Samsung Corp as well as previously

mentioned Powermat company to create a wireless charging union

created. The alliance also includes Win Industries Gill, Industries Ever,

Acustic Peiker and Telecom SK and other members, the goal is to set up

technical standards and industry dialogue mechanism for electronic

products including portable electronic products and electric vehicles, etc..

[3]

4,iNPOFi Technology

INPOFi ("power field invisible") is a new wireless charging technology. Its

wireless charging series products adopt intelligent electric transmission

wireless charging technology, with no radiation, high power conversion

efficiency, thermal effect is weak, and so on.

Intelligent iNPOFi no radiation technology with the existing other wireless

charging technology compared, iNPOFi no radiation and the electric field

pulse mode, do not produce any radiation, China Theil laboratory test

results show that radiation increases value near zero. In the performance,

Theil test chamber was also measured, the technology products, charging

transmission efficiency as high as 90%, completely changed the

traditional wireless charging a maximum of 70% lower power conversion

efficiency is low. In intelligent management, the use of chip adapter

management technology, which includes: automatic opening, closing the

charging process; automatic matching needs of the voltage, current, the

management of charging process, to ensure higher charging efficiency;

and can use a unified charging board for any product brand, model of

electronic products, safe, convenient and efficient charging. In terms of

security, while taking into account the security issues of various weak

electric charge, such as the protection of static ESD, anti charge, anti

impact, etc., and even if the power management problems occur when

the device itself, inpofi chip can automatically fuse to protect the

electronic device is not damaged. It is worth mentioning that, for smart

device manufacturers, inpofi with a tiny chip as the core, to achieve the

ultra design, only 1/4 five gross coin size, can be easily integrated into any

device, can also be integrated into various forms of wearable devices. This

is the traditional electromagnetic principle of the product can not be

achieved.

INPOFi technology as a new generation of wireless charging technology

standards, efficient, green, convenient, economy. The charging device

with the technology includes two parts of the power transmitting device

and the power receiving device, the device size, Bo Hou and the ordinary

mobile phone are equivalent, the receiving device is embedded in the

mobile phone protective sleeve, and the mobile phone is set to be

protected. In the charging process, the phone does not need to plug in

any connection line. The correlation detection shows that the

electromagnetic radiation is zero, the power conversion efficiency is

94.7%, which is close to the wire charge. Low voltage power supply,

compatible with common USB power supply, low temperature charging,

the use of effective protection equipment and battery life. [4]

Conversion device

Working principle

Wireless charging technology Schematic [5]

Using the principle of "resonance" in Physics - two of the same objects

with the same frequency can transmit energy efficiently.

1 electric power transmission line in the antenna used in the manufacture

of copper.

2 antenna with a wavelength of 10 MHz vibration, resulting in

electromagnetic waves.

3 the energy transmitted from the antenna to 2 meters (6.5 feet).

4 similarly to the frequency of the 10 MHz frequency vibration of the

laptop to receive the current, energy charging equipment.

5 did not convert the energy of the laptop to the laptop will not be re

absorbed by the antenna. The human and other objects that can't

produce 10 MHz resonance will not interfere with it.

Main features

1, from the theory, wireless charging technology for human safety and no

harm, wireless charging using the resonance principle is magnetic

resonance, only in the same frequency resonance transmission between

the coils, and other devices can not accept the band, in addition, wireless

charging technology used in the magnetic field itself is harmless. Wireless

charging technology, after all, is a new type of charging technology, in

order to take the wireless charger, wireless charger, a lot of people will be

concerned about the wireless charging technology will be like the original

Wi-Fi and mobile phone antenna just appeared, in fact, the technology

itself is harmless.

Using the wireless charging technology 2, Sang Deli induction principle

between the mobile phone charger and the magnetic energy is

transformed into electrical energy, coil and a capacitor is in charge

generated transformation. [6]

3, Sander said that the system can be widely used in the future, such as

the charging area for electric vehicles and the power transmission for the

computer chip. The charging time required for the development of this

technology is only 1/150 of the current.

4, the conversion rate has been a lot of people are worried about the

problem, Massachusetts Institute of Technology, through research shows

that the loss of wireless charging technology is higher than the cable

charging technology. Step source said: wireless charging high conversion,

but also a key factor in the application of wireless charger in the world.

However, wireless charging technology is also limited by the distance, the

future development, will need to address the issue of remote

transmission for the band and the magnetic field range of accurate

positioning.

5, the resonance control core chip is the wireless charging technology

resonance principle control center. Precision radiation range control,

magnetic field frequency, and other control is realized by chip. [7]

Market demand

With the iPhone, iPad, and so on the quantity of electricity is full of

"hungry" equipment, the rapid rise of the development of wireless

charging, such as the need to break the technology of increasing demand.

Fujitsu said in a statement: "this technology will be a collection of

compact wireless charging capabilities, as well as a number of portable

devices to charge the road. For multiple devices, there is no restriction on

the position of the device relative to the charger."

Test application

1, the test results show that the wireless transmission distance is about 15

centimeters, but Fujitsu said the wireless transmission distance can be

achieved a few meters away.

2, it is needed to point out that the farther away from the device, the

more power loss in transmission.

3, Sang Deli's system and the United States Witricity company developed

technology similar to the latter, the latter also use magnetic resonance

transmission power, transmission distance can reach a few meters away.

Social practical benefit in the application of wireless charging technology

Today, all countries in the world are scrambling to develop the wireless

charging technology. With the continuous shortage of natural resources

and the growing problem of environmental protection, electric energy to

replace other energy transport vehicles have gradually developed, electric

vehicles and electric bicycles have been widespread in people's lives. As

an electric vehicle fast charging equipment, technical problems still have

a lot of, one of which is how to use the wireless charging technology to

achieve the growing need for electric vehicles. The imperfections of the

wireless charging technology, and points out the key to the problem is

the energy loss is too big and magnetoelectric induction conversion

efficiency is low. In addition, there is a large power "wireless charging

technology," the long-distance transmission and electromagnetic

radiation on the environment and other factors have not been fully

resolved. Electric motor to achieve the wireless charging technology

advantage is to replace the original grid in-line links have many

disadvantages, and electric energy supply for a long time, parking area

area is large and the manual operation is complex and unfavorable

factors. For the past, this charging technology is only a one-time power

conversion, and a one-time electromagnetic induction power loss is small,

because the power frequency of the first stage of the transformer and the

power grid is the same (50 Hz), so there is no more than the effect of

electromagnetic radiation on the environment. However, its disadvantage

is that the charging device must be installed in advance of the power

supply and the need to lengthen the power supply leads and the

existence of some of the non safety and other factors, such as tedious

operation. With the continuous improvement of the electric power car

technology and the increase of market, it is also to facilitate the energy

supply of electric vehicles, people began to try to study how to use the

wireless charging technology for electric vehicles charging, in order to

solve many of the disadvantages of electric vehicles in the cable charging

process.

Advantages and disadvantages

"Wired charging technology" and "wireless charging technology" each

have their own advantages and disadvantages.

"Cable charging technology" advantages:

1, the one-time energy conversion, power loss is small, energy-saving

environmental protection.

2, AC / DC conversion, there is no high frequency electromagnetic

radiation.

3, the equipment and technology content is low, the economic

investment is small, and the maintenance is convenient.

4, the electric power regulation range is wide, the battery storage for

various voltage and current levels can recharge.

"Cable charging" shortcomings:

1, the equipment of the mobile carrier and power of the lead is too long,

mainly manual operation is complicated.

2, the equipment and the electric vehicle charging when the public area is

too large,

3, in the process of manual operation, extremely prone to excessive wear

and tear of equipment and other factors.

"Wireless charging technology" advantages:

1, the use of wireless electromagnetic induction charging devices, we can

make contact, wear rate is low, the application range wide, public

charging area relative reduced, but the decrease of covers an area of area

share is not too large.

2, high technology content, easy operation, can be implemented in a

relatively remote radio can change, but the transmission distance of high

power wireless charging is only limited to 5 meters, not too far.

3, easy to operate.

"Wireless charging technology," the shortcomings:

1, although the equipment technology is high, but the cost of the

equipment is high, the maintenance cost is high.

2, because the realization of long-distance power wireless equipment so

the magnetoelectric conversion, high energy consumption. The wireless

transmission distance is far, the useless loss will be greater.

3, the "wireless charging technology" device itself is the two energy

conversion, that is, the network voltage (or direct) into direct current after

a higher frequency of the switch control AC converter output. Since the

high power AC current conversion is the two time of the power

transmission, the magnetic field of the magnetic field is too large.

4, because of wireless transmission, useless power loss of magnetic

energy will rise as the "power" of the increase of wireless charging

equipment.

Today, the wireless charging technology in the small power or can show

its superiority. Such as small DC power equipment in the communication

equipment, civilian wireless communication mobile phone, micro

computer, small portable household appliances, etc.. But it is difficult to

implement high power wireless transmission. According to theory of

wireless energy transmission, the transmission distance is far, energy

consumption will be greater, and in the terminal equipment of electric

energy is small.

From the electric vehicle power required to add power is not very small,

generally small household electrical equipment of the charge current

between 0.5 amps to 2 amps. And a few tens of horsepower electric

vehicles to the required power supply current is mostly in the 5 amps to

20 amps. The electric car's power is bigger, the electric current of the

electric vehicle needs to be added. And we are making "wireless charging

equipment", its output power will be greater than 500 watts or higher. If

multiple locomotives are charged, the output of the total power output

will be straight up. Of city electric power supply system is undoubtedly

worse. In order to bring the whole city is power grids and huge economic

investment, is really worth the candle.

In addition, we can calculate the economic accounts. Charge 24 volts and

15 Amps of current to an electric vehicle charging, charging time is 10

hours, the power loss is only about 3 degrees, according to the current 0.5

corner of the city electricity price calculation, to an electric vehicle

charging costs about five cents per dollar. If the individual will be charged

to the electric car to the public wireless charging, the cost is not high, we

are here to use the general cable charging device to charge the electric

vehicle charging. We can compare, in the same electric vehicle charging

state, the power of the wireless charging device is certainly greater than

the general cable charging device. Because the "wireless charging

equipment" is certainly greater than the loss of cable charging equipment,

in view of the economic input and charging between the two devices, so

people tend to prefer to take the low economic input of cable charging

equipment to use. According to the theory of electrical engineering, we

know that the longer the magnetic circuit of the transformer, the greater

the magnetic loss. Whether it is to take the long distance transmission of

an electromagnetic -- magnetoelectric conversion, will lose a lot of power.

And the number of the converted electromagnetic magnetoelectric --

more, the power loss will be greater. And the electronic device's working

current is bigger, the aging period of the device is also more advanced,

which brings a lot of inconvenience to the maintenance and use of the

equipment.

About electric vehicle charging stations set up, in my opinion is not to

take the two way to compare. On its one-time charge, the customers still

prefer to choose the general cable charging method. I said the premise is

that the two types of charging equipment with the same technical

indicators, can be implemented in a fast charging mode and the same

charge quality. At this point, we can through the charging device of

electric energy loss parameters do a comparison, look at the economic

value and social benefits of what kind of equipment more high. Because

our society is based on the market economy of the regional sector units,

everyone wants to calculate the economic investment and return, so

every high-tech industry investment must also consider the general

recognition of the public and the industry's own economic leverage. At

the same time in the fossil energy has not reached the depletion of the

modern society, the development of electric vehicles will not be too fast,

if the battery can improve the use of a one-time charge cycle is the best

way to solve the problem. The short battery life cycle is the biggest

obstacle to the development of electric vehicle, the power and speed of

the vehicle, fuel car is still a lot of advantages.

According to the actual situation of modern energy shortage, electric

transport tool to achieve high power, wireless charging technology

industry is too early to operate. Why do you say that? Although the

development of electric vehicles can save energy and is conducive to the

protection of the environment, but the power supply system to quantify

the requirements will be greater; if the power plant construction

investment, transmission network transformation capacity and other

reasons. Also, because the power of the electric car to the greater the

amount of social ownership, the need for a long time to stop the area of

parking spaces should be expanded. In fact, the social and economic

investment cost of the high power wireless charging technology is

generally high, while the use of conventional cable charging method is

simple, one-time investment and small, but also the city's quantitative

demand and little. There is also a relative reduction in the occupied land

area, here said the reduction is because each family can implement the

energy added to the electric car, will not focus on public places to charge.

In addition, each family will not buy a higher price of wireless charging

equipment, and the charge of their own charge is much lower than public

places. So we must Zong Helai considering the implementation of high

power wireless charging technology, pace is stridden is not too large, this

is only for the convenience of the hour, and lead to the consumption of

large quantities of resources of the society as a whole is worth it?

Five

Application examples

Wireless charging technology to light two light bulbs [8]

Wireless charging technology to light two light bulbs [9].

Sander Sander force to join the Qi standard wireless charging technology,

the company has been the power of the device for the development of

several wireless chargers, such as wireless mobile power

Palm Pre is the first to use a wireless charging technology of intelligent

mobile phone, you can use the "electromagnetic induction" by an

optional wireless

Six

Developing trend

Although in the mobile phone, notebook computers, small appliances

and other fields can use wireless charging technology, but the largest

market share or mobile phone.

wireless charge

Technology trends to sum up, can be summarized as a few points:

First: simple principle

High school physics of electromagnetic coupling principle, industry is also

very familiar with, from the RFID extension of the technology, it is also

easy to accept. Receiving end on one or two chip (the final will be a single

program), one end of the charging coil, one end of the battery. Many

companies began to launch a series of chips, will accelerate the spread of

knowledge of wireless charging and universal.

Second: trouble process

Mobile phone in excess of space, especially the smart phone, it is difficult

to make up a large charging coil.

As shown in figure:

The diameter 40mm circular coil in the below would be added to the

thickness in 0.8 ~ 2 mm inorganic magnetic materials (using micro

navigation organic magnetic material to 0.2mm thickness) to increase the

thickness of the phone, this component if placed in the mobile phone

circuit board, also occupied space, run the other components. So, all of

the mobile phone structure design engineers have a headache, which

restricts or hinder the development of wireless charging products.

Become a stumbling block. Some companies launch 0.53mm thickness of

wireless charging receiver coil (antenna), there is hope to promote the

popularity of wireless charging technology in the mobile phone:

Third: universal conditions to be formed

Receiving end antenna thin, flexible, good performance, the price is cheap,

reaching these four points, wireless charging technology will be mobile

phone business to accept, otherwise just

A highbrow game technology.

Slim: overall thickness in 0.7mm. Pasted on the inside or the battery of the

mobile phone casing.

Toughness: impact, drop, which is the general requirements of the

handheld terminal, in particular, paste on the inside of the mobile phone,

often warping deformation of the external force.

It depends on the progress of new magnetic materials, the traditional

sintered magnetic material is too hard and brittle, and the popularity of

organic magnetic materials to be flexible.

Performance: the charge current in the 500-600mA is a hard indicator.

Price: wireless charging coil with a wireless charging chip over 10 yuan,

not a universal price; the chip fell to 2 yuan, the coil components in the 3

yuan is a universal inflection point. The chip price is expensive, the coil

and magnetic component is not cheap, the market is still waiting for the

state.