WO2016171459A1

WO2016171459A1 - Wireless power transmission apparatus and control method thereof

Info

Publication number: WO2016171459A1
Application number: PCT/KR2016/004095
Authority: WO
Inventors: 박수영; 박수빈; 이종헌
Original assignee: 엘지이노텍(주)
Priority date: 2015-04-20
Filing date: 2016-04-20
Publication date: 2016-10-27
Also published as: KR20160124568A

Abstract

Disclosed is a wireless power transmission apparatus. The device comprises: a charge pad; a power transmission part, which is included in the charge pad, for recognizing a wireless power reception apparatus; and a control part for controlling the power transmission part to transmit wireless power through the power transmission part to an external device, wherein the power transmission part comprises a plurality of stacked coils, and the control part is capable of controlling the magnetic field phases of the individual stacked coils. Accordingly, it is possible to improve efficiency of the device.

Description

Wireless power transmitter and control method

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless power transmitter and a control method thereof, and more particularly, to a wireless power transmitter and a control method including a plurality of charging transmitters.

Recently, with the rapid development of information and communication technology, a ubiquitous society based on information and communication technology is being made.

In order for telecommunications devices to be connected anytime and anywhere, sensors incorporating computer chips with communication functions must be installed in all social facilities. Therefore, the problem of power supply of these devices and sensors is a new problem. In addition, as the number of mobile devices such as Bluetooth handsets and music players such as iPods has rapidly increased, charging a battery has required users time and effort. In recent years, wireless power transmission technology has been attracting attention as a way to solve this problem.

Wireless power transmission or wireless energy transfer is a technology that transmits electrical energy wirelessly from a transmitter to a receiver using the principle of induction of magnetic field, which is already used by electric motors or transformers using the electromagnetic induction principle in the 1800s. Since then, there have been attempts to transmit electrical energy by radiating electromagnetic waves such as radio waves and lasers. Electric toothbrushes and some wireless razors that we commonly use are actually charged with the principle of electromagnetic induction.

To date, energy transmission using wireless may be classified into magnetic induction, electromagnetic resonance, and power transmission using short wavelength radio frequency.

The magnetic induction method uses the phenomenon that magnetic flux generated at this time causes electromotive force to other coils when two coils are adjacent to each other and current flows to one coil, and is rapidly commercialized in small devices such as mobile phones. Is going on. Magnetic induction is capable of transmitting power of up to several hundred kilowatts (kW) and has high efficiency, but the maximum transmission distance is less than 1 centimeter (cm).

The magnetic resonance method is characterized by using an electric or magnetic field instead of using electromagnetic waves or current. Since the magnetic resonance method is hardly affected by the electromagnetic wave problem, it has the advantage of being safe for other electronic devices or the human body. On the other hand, it can be utilized only in limited distances and spaces, and has a disadvantage in that energy transmission efficiency is rather low.

Short-wavelength wireless power transfer schemes, simply RF schemes, utilize the fact that energy can be transmitted and received directly in the form of RadioWave. This technology is a wireless power transmission method of the RF method using a rectenna, a compound word of an antenna and a rectifier (rectifier) refers to a device that converts RF power directly into direct current power. In other words, the RF method is a technology that converts AC radio waves to DC and uses them. Recently, research on commercialization has been actively conducted as efficiency is improved. Wireless power transfer technology can be used in various industries, such as the mobile, IT, railroad and consumer electronics industries.

On the other hand, the prior art has disclosed that a wireless power transmitter including a plurality of coils transmits power to a wireless power receiver. However, there is a demand for a technology in which the wireless power transmitter more efficiently transmits power to the wireless power receiver.

An object of the present invention to provide a wireless power transmission apparatus comprising a plurality of power transmission unit.

Another object of the present invention is to provide a wireless power transmission apparatus that accurately recognizes a wireless power receiver and performs wireless charging.

Another object of the present invention is to provide a wireless power transmission apparatus for searching for a wireless power receiver more efficiently.

Another object of the present invention is to provide a wireless power transmitter for determining a shape of a wireless power receiver and charging the receiver with a necessary part based on the shape.

Another object of the present invention is to provide a wireless power transmission apparatus for transmitting wireless power by using a wireless power transmitter having a coil stacked structure.

Technical problems to be achieved in the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned above will be clearly understood by those skilled in the art from the following description. Could be.

According to an embodiment of the present disclosure, a method of controlling a wireless power transmitter including a charging pad including a charging pad may include: recognizing a wireless power receiver through a plurality of power transmitters included in the charging pad, wherein the wireless power is provided. Specifying a power transmission group including at least one power transmission unit to transmit power to a reception device, controlling a phase of the power transmission group with respect to the wireless power reception device, and the power to be transmitted to the wireless power reception device. Adjusting the power of the transmission group, wherein at least one power transmitter included in the power transmission group may be stacked at least one coil.

The above aspects of the present invention are only some of the preferred embodiments of the present invention, and various embodiments in which the technical features of the present invention are reflected will be described in detail below by those skilled in the art. Can be derived and understood.

According to the present invention, there is an effect that a wireless power transmission apparatus including a plurality of power transmission unit is provided.

In addition, the wireless power receiver can be accurately recognized to improve the device efficiency.

In addition, since the shape of the wireless power receiver is considered and the wireless power is transmitted and received as an essential part, device efficiency and user convenience may be improved.

Another object of the present invention is to provide a wireless power transmission apparatus for transmitting wireless power by using a wireless power transmitter having a coil stacked structure, the power can be transmitted more efficiently.

The effects obtainable in the present invention are not limited to the above-mentioned effects, and other effects not mentioned above may be clearly understood by those skilled in the art from the following description. will be.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings are provided to facilitate understanding of the present invention, and provide embodiments of the present invention together with the detailed description. However, the technical features of the present invention are not limited to the specific drawings, and the features disclosed in the drawings may be combined with each other to constitute new embodiments.

1 is a view for explaining a wireless power transmission system according to an embodiment.

2 is an equivalent circuit diagram of a transmission induction coil according to an embodiment.

3 is an equivalent circuit diagram of a power source and a wireless power transmission apparatus according to an embodiment.

4 is an equivalent circuit diagram of a wireless power receiver according to an embodiment.

5 is a perspective view illustrating a wireless power transmission system including a plurality of power transmitters according to another embodiment of the present invention.

6 is a perspective view illustrating a rear surface of a terminal that is an example of a wireless power receiver.

7 is a cross-sectional view illustrating a wireless power transmission system according to an embodiment.

8 is a diagram illustrating a control method of a wireless power transmission apparatus according to an embodiment.

9 illustrates a wireless power transmitter for recognizing a wireless power receiver according to an embodiment.

10 is a diagram illustrating a method of specifying a power transmission group of a wireless transmission apparatus according to an embodiment.

11 and 12 are diagrams illustrating a wireless power transmitter for controlling a phase of a power transmitter group in order to prevent magnetic field interference according to an exemplary embodiment.

FIG. 13 is a diagram illustrating a wireless power transmitter including a plurality of stacked coils according to an embodiment.

14 is a diagram illustrating another wireless power transmitter including a plurality of stacked coils according to an embodiment.

15 and 16 are diagrams illustrating a method of controlling power according to an embodiment.

17 is a block diagram of a wireless power transfer system according to an embodiment.

18 is a more detailed block diagram of the wireless power transfer system of FIG. 17.

Hereinafter, an apparatus and various methods to which embodiments of the present invention are applied will be described in more detail with reference to the accompanying drawings. The suffixes "module" and "unit" for components used in the following description are given or used in consideration of ease of specification, and do not have distinct meanings or roles from each other.

In the description of the embodiments, when described as being formed on the "top" or "bottom" of each component, the top (bottom) or the bottom (bottom) is the two components are in direct contact with each other or One or more other components are all included disposed between the two components. In addition, when expressed as "up (up) or down (down)" may include the meaning of the down direction as well as the up direction based on one component.

In the description of the embodiments, a transmitter, a transmitter, a transmitter, a transmitter, a power transmitter, and the like may be used in combination for the convenience of the wireless power transmitter. In addition, as a representation of the wireless power receiver, a receiver, a terminal, a receiver, a receiver, a power receiver, etc. may be used interchangeably for convenience of description.

Wireless power transmission apparatus according to an embodiment of the present invention may be provided with a plurality of wireless power transmission means to wirelessly transfer power to a plurality of receivers.

Wireless power transmitter according to an embodiment of the present invention is a mobile phone (smart phone), smart phone (smart phone), laptop computer (laptop computer), digital broadcasting terminal, PDA (Personal Digital Assistants), PMP (Portable Multimedia Player) It can be used in, but is not limited to, navigation, MP3 players, and other small electronic devices.

1 is a view for explaining an example of a wireless power transmission system.

Referring to FIG. 1, the wireless power transmission system may include a power source 100, a wireless power transmitter 200, a wireless power receiver 300, and a load terminal 400.

The power source 100 may be included in the wireless power transmitter 200, but is not limited thereto.

The apparatus 200 for transmitting power wirelessly may include a transmission induction coil 210 and a transmission resonance coil 220.

The wireless power receiver 300 may include a reception resonance coil 310, a reception induction coil 320, and a rectifier 330.

Both ends of the power source 100 may be connected to both ends of the transmission induction coil 210.

The transmission resonant coil 220 may be disposed at a predetermined distance from the transmission induction coil 210.

The reception resonance coil 310 may be disposed at a predetermined distance from the reception induction coil 320.

Both ends of the receiving induction coil 320 may be connected to both ends of the rectifier 330, and the load terminal 400 may be connected to both ends of the rectifier 330. In an embodiment, the load stage 400 may be included in the wireless power receiver 300.

The power generated by the power source 100 is delivered to the wireless power transmitter 200, and the power delivered to the wireless power transmitter 200 resonates with the wireless power transmitter 200 by a resonance phenomenon. The resonance frequency values may be transmitted to the same wireless power receiver 300.

Hereinafter, the power transmission process will be described in more detail.

The power source 100 may generate AC power having a predetermined frequency and transmit the generated AC power to the wireless power transmitter 200.

The transmission induction coil 210 and the transmission resonant coil 220 may be inductively coupled. That is, the alternating current is generated by the alternating current power supplied from the power source 100, and the alternating current is also transmitted to the transmitting resonance coil 220 physically spaced by the electromagnetic induction by the alternating current. Can be derived.

Thereafter, the power delivered to the transmission resonant coil 220 may be transmitted to the wireless power receiver 300 having the same resonance frequency by the resonance using the wireless power transmitter 200 and the frequency resonance scheme.

Power may be transferred by resonance between two impedance matched LC circuits. Such resonance power transmission enables power transmission with higher transmission efficiency over longer distances than power transmission by electromagnetic induction.

The reception resonance coil 310 may receive power transmitted from the transmission resonance coil 220 by using the frequency resonance method. An AC current may flow in the reception resonant coil 310 due to the received power, and the power delivered to the reception resonant coil 310 may be inductively coupled to the reception resonant coil 310 by electromagnetic induction. Can be delivered. Power delivered to the receiving induction coil 320 may be rectified through the rectifying unit 330 and transferred to the load stage 400.

In an embodiment, the transmission induction coil 210, the transmission resonance coil 220, the reception resonance coil 310, and the reception induction coil 320 may have any one of a spiral or a helical structure. However, the present invention is not limited thereto.

The transmit resonant coil 220 and the receive resonant coil 310 may be resonantly coupled to enable power transmission at a resonant frequency.

Due to the resonance coupling of the transmission resonance coil 220 and the reception resonance coil 310, the power transmission efficiency between the wireless power transmitter 200 and the wireless power receiver 300 may be greatly improved.

The above wireless power transmission system has described power transmission by the resonant frequency method.

In addition, in the exemplary embodiment, the wireless power transmitter 200 has one transmission induction coil 210 and one transmission resonance coil 220, but the present disclosure is not limited thereto, and the plurality of transmission induction coils 210 may be used. ) And a plurality of transmission resonant coils 220. Detailed examples will be described later.

Embodiments of the present invention can be applied to power transmission by the electromagnetic induction method in addition to the resonance frequency method.

That is, in the embodiment, when the wireless power transmission system performs power transmission based on electromagnetic induction, the reception includes the transmission resonant coil 220 and the wireless power receiver 300 included in the wireless power transmitter 200. The resonant coil 310 may be omitted.

Quality factor and coupling coefficient may have important meanings in wireless power transmission. That is, the power transmission efficiency may have a proportional relationship with each of the quality index and the coupling coefficient. Therefore, as the value of at least one of the quality index and the coupling coefficient increases, power transmission efficiency may be improved.

The quality factor may refer to an index of energy that may be accumulated in the vicinity of the wireless power transmitter 200 or the wireless power receiver 300.

The quality factor may vary depending on the operating frequency w, the shape, dimensions, materials, and the like of the coil. The quality index can be represented by the following equation.

[Equation 1]

Q = w * L / R

L is the inductance of the coil, and R is the resistance corresponding to the amount of power loss generated in the coil itself.

The quality factor may have an infinite value from 0, and as the quality index increases, power transmission efficiency between the wireless power transmitter 200 and the wireless power receiver 300 may be improved.

Coupling Coefficient refers to the degree of magnetic coupling between the transmitting coil and the receiving coil and has a range of 0 to 1.

Coupling coefficient may vary according to the relative position or distance between the transmitting coil and the receiving coil.

2 is an equivalent circuit diagram of a transmission induction coil.

As shown in FIG. 2, the transmission induction coil 210 may be composed of an inductor L1 and a capacitor C1, and may be configured as a circuit having appropriate inductance and capacitance values.

The transmission induction coil 210 may be configured as an equivalent circuit having both ends of the inductor L1 connected to both ends of the capacitor C1. That is, the transmission induction coil 210 may be configured as an equivalent circuit in which the inductor L1 and the capacitor C1 are connected in parallel.

The capacitor C1 may be a variable capacitor, and impedance matching may be performed as the capacitance of the capacitor C1 is adjusted. Equivalent circuits of the transmit resonant coil 220, the receive resonant coil 310, and the receive induction coil 320 may also be the same as or similar to those shown in FIG. 2, but are not limited thereto.

As shown in FIG. 3, the transmission induction coil 210 and the transmission resonant coil 220 may be formed of inductors L1 and L2 and capacitors C1 and C2 having inductance values and capacitance values, respectively.

As shown in FIG. 4, the reception resonance coil 310 and the reception induction coil 320 may be formed of inductors L3 and L4 and capacitors C3 and C4 having inductance values and capacitance values, respectively.

The rectifier 330 may convert the DC power received from the reception induction coil 320 to DC power to transfer the converted DC power to the load terminal 400.

Specifically, although not shown, the rectifier 330 may include a rectifier and a smoothing circuit. In an embodiment, the rectifier may be a silicon rectifier and may be equivalent to the diode D1 as shown in FIG. 4, but is not limited thereto.

The rectifier may convert AC power received from the reception induction coil 320 to DC power.

The smoothing circuit may output the smooth DC power by removing the AC component included in the DC power converted by the rectifier. In the exemplary embodiment, as shown in FIG. 4, the rectifying capacitor C5 may be used, but is not limited thereto.

The DC power transmitted from the rectifier 330 may be a DC voltage or a DC current, but is not limited thereto.

The load stage 400 can be any rechargeable battery or device that requires direct current power. For example, the load stage 400 may mean a battery.

The wireless power receiver 300 may be mounted on an electronic device that requires power, such as a mobile phone, a notebook, a mouse, and the like. Accordingly, the reception resonance coil 310 and the reception induction coil 320 may have a shape that matches the shape of the electronic device.

The wireless power transmitter 200 may exchange information with the wireless power receiver 300 using in band or out of band communication.

In band communication may refer to a communication of exchanging information between the wireless power transmitter 200 and the wireless power receiver 300 using a signal having a frequency used for wireless power transmission. To this end, the wireless power receiver 300 may further include a switch, and may or may not receive power transmitted from the wireless power transmitter 200 through a switching operation of the switch. Accordingly, the wireless power transmitter 200 may detect an on or off signal of a switch included in the wireless power receiver 300 by detecting the amount of power consumed by the wireless power transmitter 200.

In detail, the wireless power receiver 300 may change the amount of power consumed by the wireless power transmitter 200 by changing the amount of power absorbed by the resistor using a resistor and a switch. The apparatus 200 for transmitting power wirelessly may acquire state information of the load terminal 400 by detecting a change in power consumed. The switch and the resistive element can be connected in series. In an embodiment, the state information of the load stage 400 may include information about the current charge amount and the charge amount trend of the load stage 400. The load stage 400 may be included in the wireless power receiver 300.

More specifically, when the switch is opened, the power absorbed by the resistive element becomes zero, and the power consumed by the wireless power transmitter 200 also decreases.

When the switch is short-circuited, the power absorbed by the resistor element is greater than zero, and the power consumed by the wireless power transmitter 200 increases. When the wireless power receiver repeats such an operation, the wireless power transmitter 200 may detect power consumed by the wireless power transmitter 200 and perform digital communication with the wireless power receiver 300.

The apparatus 200 for transmitting power wirelessly may receive state information of the load terminal 400 according to the above operation and may transmit power appropriate thereto.

On the contrary, the wireless power transmitter 200 may include a resistor and a switch on the side of the wireless power transmitter 200 to transmit the state information of the wireless power transmitter 200 to the wireless power receiver 300. In the embodiment, the state information of the wireless power transmitter 200 may include the maximum amount of power that the wireless power transmitter 200 may transmit, and the wireless power receiver 300 that the wireless power transmitter 200 provides power. The number and the amount of available power of the wireless power transmission apparatus 200 may be included.

Next, out-of-band communication will be described.

Out-of-band communication refers to a communication for exchanging information for power transmission by using a separate frequency band instead of a resonant frequency band. Each of the wireless power transmitter 200 and the wireless power receiver 300 may be equipped with an out-of-band communication module so that information necessary for power transmission may be exchanged between the wireless power transmitter 200 and the wireless power receiver 300. The out of band communication module may be mounted to the power source 100, but is not limited thereto. In an embodiment, the out-of-band communication module may use a short range communication method such as Bluetooth, Zigbee, WLAN, or Near Field Communication (NFC), but is not limited thereto.

Referring to FIG. 5, the apparatus 200 for transmitting power wirelessly may include a charging pad 510. Here, the charging pad 510 may include a plurality of power transmitters (1, 1), (1, 2), .. (6, 6).

The charging pad 510 may include the power source shown in FIG. 1 and a wireless power transmitter (eg, a transmitting device). That is, a power source and a plurality of wireless power transmitters (eg, transmitters) may be built in the charging pad 510. The charging pad 510 may have a circular, elliptical square, or rectangle as viewed from above, but is not limited thereto.

The top surface of the charging pad 510 may be in surface contact with any one surface of the wireless power receiver 300. The shape of at least a portion of the upper surface of the charging pad 510 may be the same as the shape of the rear surface of the wireless power receiver 300, but is not limited thereto.

However, the wireless power receiver 300 will be described with reference to the terminal 300 as an example.

Each of the wireless power transmitters (1,1), (1,2), ..., (6,6) built in the charging pad 510 has a transmission coil (210, 220 of FIG. 1) shown in FIG. ) May be included. In this case, each of the wireless power transmitters (1, 1), (1, 2), ..., (6, 6) may also include a plurality of transmission coils (not shown), but the embodiment is not limited thereto.

The transmission coils (not shown) provided in each of the wireless power transmitters (1,1), (1,2), ..., (6,6) may be disposed to face the top surface of the charging pad 510. Can be. The transmitting coil (not shown) may be disposed to be parallel to the top surface of the charging pad 510 so that the power of the transmitting coil (not shown) is uniformly transmitted to the terminal 300.

Each of the plurality of power transmitters (1, 1), (1, 2), ..., (6, 6) may be provided with power from the power source 100 described above. In particular, the power source 100 may be configured in plural and match each of the plurality of power transmitters (1, 1), (1, 2), ..., (6, 6).

The apparatus 200 for transmitting power wirelessly may simultaneously transmit wireless power to a plurality of devices such as the apparatus 300 for receiving power wirelessly.

The wireless power receiver 300 may include a part of the equivalent circuit shown in FIG. 4. For example, the reception induction coil 320, the rectifier 330 and the load stage 400 may be included. The apparatus 300 for receiving wireless power may include various types of devices. The wireless power receiver 300 includes a mobile phone, a smart phone, a laptop computer, a digital broadcasting terminal, a personal digital assistant (PDA), a portable multimedia player (PMP), navigation, and an MP3 player. And other small electronic devices, but is not limited thereto.

The wireless power receiver 300 may refer to any electronic device that includes a battery for charging and may perform a predetermined electronic function by using a power charged in the battery (not shown). . For example, the wireless power receiver 300 may include a mobile device such as a smartphone or a tablet PC or a home appliance such as a television, a refrigerator, or a washing machine.

The wireless power receiver 300 may include the wireless power receiver coil and the load terminal illustrated in FIG. 1. That is, the wireless power receiver coil and the load terminal may be built in the wireless power receiver 300.

The wireless power receiver 300 may be placed on an upper surface of the charging pad 510 for charging. When the wireless power receiver 300 is placed, the front cover 22 of the wireless power transmitter 300 faces upward and the rear cover 24 of the wireless power transmitter 300 contacts the top surface of the charging pad 510. Can be. Accordingly, power may be wirelessly supplied from the charging pad 510 to be charged at the load end.

As shown in FIG. 6, the wireless power receiver 300 will be described with the terminal 300 as an example.

The receiving coil 32 and the magnet 30 may be disposed adjacent to the rear surface of the terminal 300. The receiving coil 32 may also be disposed to face the at least one transmitting coil disposed on the charging pad 510, an upper surface of the charging pad 510, and a rear cover 24 of the wireless terminal 300. In particular, when the receiving coil 32 of the terminal 300 is positioned to be in parallel with at least one transmitting coil disposed on the charging pad 510, the receiving coil of the terminal 300 is separated from the transmitting coil of the charging pad 510. The power transfer efficiency of the power delivered to 32 may be maximized.

The structure of the wireless power transmission system according to the embodiment will be described in more detail with reference to FIG. 7.

FIG. 7 illustrates a portion of FIG. 5 in more detail. The charging pad 510 includes a plurality of power transmitters (1, 1) to (1, 5).

Each of the plurality of power transmitters (1, 1) to (1, 5) may include a transmission coil 14-1 to 14-5 and a plurality of first magnets 12-1 to 12-5. . The plurality of transmission coils 14-1 to 14-5 and the plurality of first magnets 12-1 to 12-5 may be disposed adjacent to an upper surface of the charging pad 510. The transmitting coils 14-1 to 14-5 and the magnets 12-1 to 12-5 may be disposed on the same surface.

The transmission coils 14-1 to 14-5 may be transmission transmission coils and / or transmission resonance coils illustrated in FIG. 1. For example, in the case of the resonance method, both the transmission induction coil and the transmission resonant coil may be used, whereas in the case of the electromagnetic induction method, only the transmission induction coil may be used.

Each of the plurality of transmission coils 14-1 to 14-5 may be disposed to surround each of the plurality of first magnets 12-1 to 12-5. For example, the first transmission coil 14-1 may surround the first magnet 12-1, the second transmission coil 14-2 may surround the second magnet 12-2, The third transmission coil 14-3 may surround the third magnet 12-3, and the fourth transmission coil 14-4 may be configured to surround the fourth magnet 12-4, The fifth transmitting coil 14-5 may be configured to surround the fifth magnet 12-5. However, since this drawing is a sectional drawing, it is difficult to display it on a drawing.

The transmission coils 14-1 to 14-5 have several numbers of turns, and may be spaced apart from adjacent transmission coils 14-1 to 14-5, but are not limited thereto. The transmitting coils 14-1 to 14-5 may be arranged to be parallel to the virtual horizontal plane. The central area of the transmitting coils 14-1 to 14-5 having such a structure may be an empty space. In addition, the transmission coils 14-1 to 14-5 may be inclined to have a predetermined angle with respect to the virtual horizontal plane.

The plurality of first magnets 12-1 to 12-5 may be disposed in the central region of the transmitting coils 14-1 to 14-5. The thickness of the plurality of first magnets 12-1 to 12-5 may be equal to or greater than or less than the thickness of the transmission coils 14-1 to 14-5. The plurality of first magnets 12-1 to 12-5 according to the intensity of magnetic flux density required for the plurality of first magnets 12-1 to 12-5 and the occupied area of the magnets 12-1 to 12-5. ) And the area of the plurality of first magnets 12-1 to 12-5 may vary.

The terminal 20 may include a shielding member 26, a receiving coil 32, and a second magnet 30. The receiving coil 32 and the second magnet 30 may be disposed on the same surface.

Although the terminal 20 is expressed as being in contact with the charging pad 510 of the wireless power transmitter 200, the terminal 20 may be spaced apart from the charging pad 510 at a predetermined distance.

The terminal 20 may be larger or smaller in size than each of the plurality of power transmitters (1,1) to (1,5), but is not limited thereto.

The receiving coil 32 may be a receiving resonant coil and / or a receiving induction coil shown in FIG. 1. For example, in the case of the resonance method, both the reception resonance coil and the reception induction coil are used, whereas in the case of the electromagnetic induction method, only the reception induction coil may be used.

The receiving coil 32 may be arranged to surround the second magnet 30. The receiving coil 32 may have several turns, and may be spaced between adjacent receiving coils 32. The receiving coil 32 may be arranged to be parallel to the virtual horizontal plane. The central region of the receiving coil 32 having such a structure may be an empty space. In addition, the receiving coil 32 may be inclined to have a predetermined angle with respect to the virtual horizontal plane.

The second magnet 30 may be disposed in the central area of the receiving coil 32. The central region of the receiving coil 32 may be smaller than the central region of the transmitting coils 14-1 to 14-5, but is not limited thereto. The thickness of the second magnet 30 may be equal to or greater than or less than the thickness of the receiving coil 32. The thickness of the second magnet 30 and the area of the second magnet 30 may vary depending on the strength of the magnetic flux density required for the second magnet 30 and the area occupied by the second magnet 30.

The second magnet 30 allows the charging pad 510 to detect whether the terminal 20 is close to or touched.

For this detection, the charging pad 510 may further include a hall sensor 16-1 to 16-5. The hall sensors 16-1 to 16-5 may be disposed between the top surface of the charging pad 510 and the first magnets 12-1 to 12-5, but are not limited thereto. The hall sensors 16-1 to 16-5 may be disposed closer to the top surface of the charging pad 510 than the first magnets 12-1 to 12-5. The hall sensors 16-1 to 16-5 are connected to the charging pad 510 between the first magnets 12-1 to 12-5 of the charging pad 510 and the second magnet 30 of the terminal 20. Can be arranged. The hall sensors 16-1 to 16-5 detect only the intensity of the magnetic flux density of the first magnets 12-1 to 12-5 when the terminal 20 is absent. However, when the terminal 20 comes close to the charging pad 510, the hall sensors 16-1 to 16-5 may not only have the strength of the magnetic flux density of the first magnets 12-1 to 12-5 but also the first to the charging pads 510. The strength of the magnetic flux density of the two magnets 30 can be detected. Therefore, the charging pad 510 is placed on the charging pad 510 based on the intensity of the magnetic flux density of the first magnets 12-1 to 12-5 detected when the terminal 20 is absent. When the intensity of the magnetic flux density of the first magnet (12-1 ~ 12-5) and the magnetic flux density of the second magnet 30 is detected when the power is detected and the change width (α) of the magnetic flux density is more than the threshold value It is determined that the 20 is placed on the charging pad 510 for charging, and the charging of the terminal 20 may proceed.

In the above example, the Hall sensors 16-1 to 16-5 are described as being disposed between the top surface of the charging pad 510 and the first magnets 12-1 to 12-5, but this is one embodiment. In another embodiment of the present invention, the Hall sensors 16-1 to 16-5 are disposed on one side of the lower ends of the first magnets 12-1 to 12-5, or the transmitting coils 14-1 to. It should be noted that it may be disposed on the lower side of 14-5).

To this end, the second magnet 30 may be made of a material causing a change width α of the magnetic flux density above a threshold value. For example, the threshold may be 32G. The threshold required by the standard may be 40G.

The second magnet 30 may be an electrical sheet. For example, the electrical steel sheet may contain at least 1% to 5% of silicon (Si), but is not limited thereto. The silicon content of the second magnet 30 may vary so as to cause a change width α of the magnetic flux density above a threshold required by a standard or a customer.

For example, the receiving coil 32 and the second magnet 30 may be attached to the rear surface of the shield member 26 using the adhesive 28. A printed circuit board on which the electronic components including the power source, the AC power generator, and the controller are mounted may be disposed on the shielding member 26.

The shielding member 26 may shield the magnetic field induced by the coil so that the magnetic field does not affect the electronic component, thereby preventing malfunction of the electronic component.

Hereinafter, a method of recognizing and controlling the wireless power receiver by the wireless power transmitter will be described in detail.

8 is a diagram illustrating a control method of a wireless power transmission apparatus according to an embodiment. Reference numerals refer to FIG. 5 (eg, a plurality of power transmitters), FIG. 7 (eg, a hall sensor), and FIG. 17 (eg, a controller) to be described later.

First, the controller 17 of the wireless power transmitter 200 recognizes the wireless power receiver 300 through the plurality of power transmitters (1, 1) to (6, 6) (S810).

Each of the plurality of power transmitters ((1,1) to (6,6)) may include Hall sensors 16-1 to 16-n, and the control unit 17 may include each Hall sensor 16-1 to. The wireless power receiver 300 may be recognized through the magnetic field change of 16-n).

Specifically, the hall sensors 16-1 to 16-n may include a plurality of power transmitters ((1, 1) to corresponding to each of the hall sensors 16-1 to 16-n under the control of the controller 17. The magnetic flux density intensity of the transmitting coil included in (6, 6)) can be measured.

In this case, the hall sensors 16-1 to 16-n are strengths of magnetic flux densities when the magnet or metal member included in the wireless power receiver 300 approaches, but the wireless power receiver 300 does not approach. And a change in the intensity of the magnetic flux density using the intensity of the magnetic flux density when the wireless power receiver 300 approaches.

Although the Hall sensors 16-1 to 16-n are described as being included in each of the plurality of power transmitters ((1, 1) to (6, 6)), the plurality of power transmitters ((1, 1) to (6). 6)) may be disposed in a predetermined area of the charging pad 510.

The controller 17 controls the plurality of power transmitters ((1, 1) to (6, 6)) to drive the hall sensors 16-1 to 16-n starting from the outermost part to the center, thereby providing wireless power. The receiving device 300 may be recognized.

On the other hand, the control unit 17 detects the change in the input impedance of the plurality of power transmitters (1,1) to (6,6) even if there is no Hall sensor, magnet (metal member), etc., and changes the impedance above a certain threshold value. Occurs, the wireless power receiver 300 may be recognized.

Specifically, for example, in the case of an induction method (eg, PMA (Power Matters Alliance)), the controller 17 performs analog ping, and in the case of a resonance method (eg, A4WP (Alliance For Wireless Power)), the controller ( 17) may transmit a beacon signal.

In the case of the inductive method, the wireless power receiver 300 transmits a feedback signal to the plurality of power transmitters ((1,1) to (6,6)) in the in-band, and in the case of a resonance method, the wireless power receiver. The 300 may transmit a feedback signal to the plurality of power transmitters (1,1) to (6,6) in an out-of-band manner.

Then, the controller 17 may detect an input impedance change of more than a threshold formed in the plurality of power transmitters (1, 1) to (6, 6) through a sensor (eg, an impedance change detection sensor). In addition to the above-described case, the controller 17 may recognize the wireless power receiver 300 using a pressure sensor, an optical sensor, or the like.

After step S810, the controller 17 specifies a power transmission group including at least one power transmitter to transmit power to the wireless power receiver 300 (S820).

The controller 17 may include at least one value exceeding a threshold value when each of the at least one power transmitter changes a magnetic field (or input impedance) change value with the wireless power receiver 300. The power transmission unit may be specified as the power transmission group 1010.

That is, the controller 17 may specify a power transmission group 1010 capable of transmitting power most efficiently among the plurality of power transmission units (1, 1) to (6, 6).

Meanwhile, the controller 17 uses the power transmitter that recognizes the wireless power receiver 300 among the plurality of power transmitters (1,1) to (6,6) to form a shape of the wireless power receiver 300. The scan may specify at least one power transmission group to transmit power to the wireless power receiver.

The power transmitter 1010 may be a power transmitter that transmits power to the wireless power receiver 300.

In addition, the power transmission group may include a power transmission unit including a hall sensor that recognizes the wireless power receiver 300.

The controller 17 may perform a fine scan of the wireless power receiver 300 through the power transmitter that recognizes the wireless power receiver 300. A detailed method will be described in detail with reference to FIG. 10 and will be omitted here.

After step S820, the controller 17 controls the phase of the power transmission group for the wireless power receiver (S830).

The controller 17 may select the first power transmitter having excellent coil alignment with the receiver 300 among the specified power transmitter. Here, the power transmission unit having excellent alignment means the power transmission unit having the greatest size of the magnetic field formed with the wireless power receiver, so that the battery of the wireless power receiver is filled with power.

In addition, the controller 17 may control the phase of the power transmission group with respect to the receiving device based on the first power transmitter. A detailed method will be described later.

After step S830, the controller 17 adjusts power of the power transmission group to be transmitted to the wireless power receiver (S840).

The controller 17 may adjust the power of the power transmission group in consideration of the distance and efficiency with respect to the receiver since the reception power of the wireless power receiver 300 is limited.

For example, the controller 17 may preferentially supply power to the wireless power receiver 300 and the power transmitter having the best alignment, and may perform power supply to the surroundings.

In addition, the controller 17 cuts off the power of the power transmitter having the least alignment with the wireless power receiver 300, and powers the power transmitter from the power transmitter disposed outside the power transmitter to the power transmitter disposed at the center of the power transmitter. Can be supplied. A more detailed description will be given later.

According to FIG. 9, the controller 17 is centered from the wireless power transmitters (1,1), (1,6), (6,1), and (6,6) disposed outside the charging pad 510. The wireless power receiver 300 may be recognized in the direction of the wireless power transmitter disposed in the wireless power transmitter.

The controller 17 may recognize the wireless power receiver 300 in various ways in addition to the above-described method. For example, the control unit 170 is a wireless power transmitter (1,1), (1,6), (6,1), (6, 6)) may recognize the wireless power receiver 300, but the embodiment is not limited thereto.

In addition, the controller 17 may automatically recognize the wireless power receiver 300. The controller 17 may recognize the proximity of the wireless power receiver 300 through the magnetic field change through the hall sensors 16-1 to 16-n.

Here, the Hall sensors 16-1 to 16-n are included in the wireless power transmitters (1, 1) to (6, 6), respectively, but may be disposed in other areas of the charging pad.

According to FIG. 10, the controller 17 may specify at least one power transmitter that generates a change in a predetermined magnetic field as the power transmitter 1010.

The controller 17 may include a power transmitter configured to transmit a power transmitter having a magnitude of a magnetic field between the wireless power transmitters (1,1) to (6,6) and the wireless power receiver 300 that exceeds a preset threshold value. 1010).

In addition, since the wireless power receiver 300 may be a rectangular parallelepiped, a circular shape, an elliptical shape, or the like, the controller 17 may specify a power transmission group based on the shape of the wireless power receiver 300.

For example, assuming that the power transmission group 1010 is configured horizontally and vertically, the controller 17 may specify the power transmission unit in the directions (2, 2) to (2, 4). Then, the controller may specify from the (3,2) power transmitter to the (3,4) power transmitter. After that, the controller can specify from (4,2) to (4,4).

That is, through the magnetic field change, the controller 17 may sequentially select at least one power transmitter included in the power transmitter 1010.

The controller 17 may first find a power transmitter having the strongest magnetic field and specify the power transmitter 1010 based on the power transmitter, but is not limited thereto.

FIG. 11 is a diagram illustrating a case where phases are different between the center transmitters 3 and 3 and the adjacent transmitters.

According to FIG. 11, the controller 17 may determine the phases of the magnetic fields of all the power transmitters (2, 2) to (4, 4) of the power transmitter group 1010.

The controller 17 may adjust the phase of the peripheral power transmitter based on the power transmitters 3 and 3 of the most center.

Accordingly, more efficient wireless power transmission may be enabled.

After the controller 170 selects the first power transmitters 3 and 3, the controller 170 sets the phase of the power transmitters immediately adjacent to (2,3), (3,2), (3,4) and (4,3). It may be adjusted to be in phase with the power transmitters 3 and 3. This is also the situation shown in FIG.

For example, if the first power transmitter 3,3 is in a positive phase (eg, a direction in which the magnetic field is directed upwards and downwards), the controller 17 immediately adjacent (2,3), (3,2), (3 (4), (4,3) The phase of the power transmitter can be set to (+) in the negative phase (e.g., the direction from which the magnetic field is directed from top to bottom).

In this case, the controller 17 may control the phase between adjacent power transmitters to prevent interference between power transmitters.

In addition, the controller 17 is a power transmitter ((2,2), (2,4), (4,2), (4,4)) that is not immediately adjacent to the first power transmitter (3,3). Since the phase of P is the same as that of the first power transmitters (3, 3), it does not need to be adjusted.

FIG. 13 is a diagram illustrating a wireless power transmitter equipped with a plurality of stacked coils, according to an exemplary embodiment.

According to FIG. 13, a plurality of power transmitters ((3, 2), (3, 3) and (3, 4) of FIG. 11 are illustrated.

The plurality of power transmitters (3, 2), (3, 3), and (3, 4) may include a plurality of stacked coils. Specifically, the (3,2) power transmitter may include two coils 1210-1 and 1210-2, and the (3,3) power transmitter may include three coils 1220-1, 1220-2, and 1220. -3), and the (3,4) power transmitter may include three coils 1230-1, 1230-2, 1230-3. FIG. 13 illustrates an embodiment in which the number of coils is determined from a controller according to an output of a receiver.

Each of the plurality of coils described above may be connected to a separate power source, and each of the plurality of power transmitters (3, 2), (3, 3), and (3, 4) may be connected to one power source. In addition, the number of coils used by the power transmitter to transmit power may be adjusted according to the output of the receiver. As the number of coils is adjusted, the number of turns of coils included in each power transmitter is increased or decreased.

The controller 17 may supply a current to configure the same phase to the stacked coils included in each of the plurality of power transmitters (3, 2), (3, 3), and (3, 4).

When the number of turns of each of the plurality of power transmitters (3, 2), (3, 3), and (3, 4) increases, the strength of the magnetic field also increases.

As a result, greater power may be supplied to the wireless power receiver 300.

Meanwhile, in the present specification, the wireless power transmitter may include a plurality of coils in which each of the plurality of power transmitters is stacked. However, this is only an exemplary embodiment, and may include a plurality of stacked coils. It will be described below.

14 is a diagram illustrating another wireless power transmitter equipped with a plurality of stacked coils according to an embodiment.

According to FIG. 14, the wireless power transmitter 10 includes one wireless power transmitter 20.

The wireless power transmitter 20 includes one wireless power transmitter 20.

The wireless power transmitter 20 may include a plurality of stacked coils 1310-1 to 1310-3. Each of the plurality of stacked coils 1310-1 to 1310-3 may be connected to separate power sources, and may be simultaneously connected to one power source.

The wireless power transmitter 10 may be configured to form a magnetic field in all or part of the plurality of stacked coils 1310-1 to 1310-3 based on a required power source of the wireless power receiver 22.

When the magnetic field is formed in two or more coils in the plurality of stacked coils 1310-1 to 1310-3, the wireless power transmitter 10 may adjust the magnetic field phase of the coil in one direction.

According to FIG. 15, the controller 17 may control power based on the first power transmitters 3 and 3. First, the reception limit power of the reception device may be determined to provide power from the first power transmitters 3 and 3, and then power may be provided around the first power transmitters 3 and 3.

If the first power transmitters 3 and 3 can provide all of the required power capacities of the wireless power receiver 300, the controller 17 may provide only the first power transmitters 3 and 3 to provide power. Can be controlled.

Alternatively, the control unit 17 may further extend the life of the power transmission unit by providing power in a distributed manner to the first power transmission units 3 and 3 and the peripheral power transmitter.

For example, when the power for wireless power transmission is turned on to the first power transmitters 3 and 3, and the power of the first power transmitters 3 and 3 is insufficient to charge the receiving device 300, the power is reduced. Power may be turned on in the power transmitter of the transmission group 1010 adjacent to the first transmitters 3 and 3.

In addition, when the first power transmitters 3 and 3 include a plurality of stacked coils, larger power may be transmitted to the wireless power receiver 300.

Here, the control unit 17 is a power transmission unit ((1,1) to (1,6), (2,1), (2,5), (2,6), (3) except for the power transmission group 1010. , 1), (3,5), (3,6), (4,1), (4,5), (4,6), (5,1) ~ (5,6), (6,1 ) ~ (6, 6)) can be turned off. In this case, the device efficiency can be improved by turning off the power transmitter of the less efficient power transmitter.

In addition, the controller 17 can drive the above-described power control simultaneously with the power transmission group 1010 or the non-power transmission group 1010.

In addition, the controller 17 may determine the reception request power of the reception device 300, and allocate power to each of the power transmitters based on the transmission efficiency of each of the power transmitters included in the power transmitter group 1010. In this case, power may be most efficiently provided to the receiving device 300.

FIG. 16 is a diagram showing that the control unit 13 turns on the power from the peripheral power transmitter to the first power transmitter in the power transmitter group.

According to FIG. 16, in contrast to FIG. 15, the controller 13 may turn on the power from the vicinity of the power transmission group and later turn on the power of the first power transmission units 3 and 3.

In addition to the above-described method, the battery of the power receiver 300 may be charged in various ways.

According to FIG. 17, the wireless power transmitter 200 may include a controller 17 and a plurality of power transmitters (1, 1) to (n, n).

In addition, the wireless power transmitter 200 may transmit power to the wireless power receiver 300.

Since the external shape of the charging pad 510 and the terminal 20 has been described above, a circuit configuration embedded in the charging pad 510 and the terminal 20 will be described below.

The charging pad 510 may include a power source, an AC power generator 19, a controller 17, a transmission coil 14, a first magnet 12, and a hall sensor 16.

Here, each of the power transmitters (1, 1) to (n, n) may include a power source, an AC power generator 19, and a transmitter coil 14. Alternatively, the source may be shared and may include an AC power generating unit and a transmitting coil, respectively. Alternatively, the source and the AC power generator may be shared, and may include transmission coils, respectively.

The power source produces alternating current or direct current power. The rectifier may convert AC power into first DC power and convert the converted first DC power into second DC power.

The AC power generator 19 may convert the power of the power source into AC power under the control of the controller 17. The AC power converted by the AC power generator 19 may be transmitted to the terminal 20 through the transmission coil 14.

The controller 17 may control the AC power generator 19 based on the change in the intensity B1 and B2 of the magnetic flux density detected by the hall sensor 16.

In addition, the controller 17 may control the AC power generator 19 using a change amount of impedance even without using the hall sensor 16.

The method according to the embodiment described above may be stored in a computer-readable recording medium that is produced as a program for execution on a computer, and examples of the computer-readable recording medium include ROM, RAM, CD-ROM, magnetic tape , Floppy disks, optical data storage devices, and the like, and also include those implemented in the form of carrier waves (eg, transmission over the Internet).

The computer readable recording medium can be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion. In addition, functional programs, codes, and code segments for implementing the above-described method may be easily inferred by programmers in the art to which the embodiments belong.

It is apparent to those skilled in the art that the present invention can be embodied in other specific forms without departing from the spirit and essential features of the present invention.

Accordingly, the above detailed description should not be construed as limiting in all aspects and should be considered as illustrative. The scope of the invention should be determined by reasonable interpretation of the appended claims, and all changes within the equivalent scope of the invention are included in the scope of the invention.

The present invention relates to wireless charging technology, and may be applied to an apparatus and system for controlling wireless power transmission.

Claims

In the control method of the wireless power transmission device equipped with a charging pad,

Recognizing a wireless power receiver through a plurality of power transmitters included in the charging pad;

Specifying a power transmission group including at least one power transmission unit to transmit power to the wireless power receiver;

Controlling the phase of the power transmission group for the wireless power receiver; and

Adjusting the power of the power transmission group to be transmitted to the wireless power receiver;

The control method of the wireless power transmission apparatus including at least one power transmission unit included in the power transmission group at least one stacked coil.
The method of claim 1,

Recognizing the wireless power receiver,

The control method of the wireless power transmitter for recognizing the wireless power receiver by a change in the magnetic field using the Hall sensor included in each of the plurality of power transmitter.
The method of claim 2,

And each of the plurality of power transmitters recognizes a wireless power receiver by measuring a change in a magnetic field during radio wave transmission and radio wave reception using the Hall sensor.
The method of claim 1,

Recognizing the wireless power receiver,

The control method of the wireless power transmission device to recognize the receiving device by scanning from the edge of the charging pad toward the center of the charging pad.
The method of claim 1,

The step of specifying the power transmission group,

Each of the at least one power transmitter specifies the at least one power transmitter that exceeds the threshold when the magnetic field change value with the wireless power receiver exceeds a preset threshold. Control method of a wireless power transmission device.
The method of claim 1,

The step of specifying the power transmission group,

Scan the shape of the wireless power receiver,

And controlling the power transmission group based on the scanned shape of the wireless power receiving apparatus.
The method of claim 1,

Controlling the phase of the power transmission group,

Selecting a first power transmitter having excellent coil alignment between the receiver and the power transmitter among the power transmitters; and

And controlling a phase of the power transmission group with respect to the receiving device based on the first power transmission unit.
The method of claim 7, wherein

Controlling the phase of the power transmission group,

The control method of the wireless power transmitter of claim 1, wherein the phase of the magnetic field is equally controlled between the power transmitter adjacent to the first power transmitter and the wireless power receiver.
The method of claim 1,

Adjusting the power of the power transmission group,

And determining the reception request power of the reception device, and allocating power to each of the power transmitters based on the transmission efficiency of each power transmitter included in the power transmitter group.
The method of claim 7, wherein

Adjusting the power of the power transmission group,

The control method of the wireless power transmitter of claim 1, wherein the reception limit power of the receiver is determined, and the power of a power transmitter not included in the power transmitter is turned off.
The method of claim 7, wherein

Adjusting the power of the power transmission group,

Based on the reception limit power, when the power for wireless power transmission is turned on in the first power transmitter, and the power of the first power transmitter is insufficient to charge the receiver, the first power among the power transmitters; A control method for a wireless power transmitter, characterized in that the power is turned on in the power transmitter adjacent to the transmitter.
The method of claim 1,

Adjusting the power of the power transmission group,

And controlling the power of the entire power transmitter included in the power transmitter group at once based on the required power of the receiver.
The method of claim 7, wherein

Adjusting the power of the power transmission group,

And when the power of the first power transmitter is sufficient to charge the receiver, charging the receiver using only the first power transmitter.
In the wireless power transmission apparatus,

A charging pad;

A plurality of power transmitters included in the charging pad and recognizing a wireless power receiver; and

And a control unit specifying a power transmission group including at least one power transmission unit to transmit power to the wireless power receiver.

At least one power transmission unit of the power transmission group, at least one stacked coil,

The control unit,

And controlling the phase of the power transmission group with respect to the wireless power reception device, and adjusting the power of the power transmission group to be transmitted to the wireless power reception device.
The method of claim 14,

Each of the power transmitters includes a hall sensor,

The control unit,

And a plurality of power transmitters to control the plurality of power transmitters to recognize the wireless power receiver through a magnetic field change by using a hall sensor included in each of the plurality of power transmitters.
The method of claim 15,

The control unit,

And controlling each of the plurality of power transmitters to recognize a wireless power receiver by measuring a change in a magnetic field during radio wave transmission and radio wave reception using the Hall sensor.
The method of claim 14,

The control unit,

And controlling each of the plurality of power transmitters to scan the edge of the charging pad toward the center of the charging pad to recognize the receiver.
The method of claim 14,

The control unit,

Each of the at least one power transmitter specifies the at least one power transmitter that exceeds the threshold when the magnetic field change value with the wireless power receiver exceeds a preset threshold. Wireless power transmitter.
The method of claim 14,

The control unit,

And scanning the shape of the wireless power receiver so as to specify the power transmission group based on the scanned shape of the wireless power receiver.
The method of claim 14,

The control unit,

A wireless power source for selecting a first power transmitter having excellent coil alignment with the receiver from among the power transmitter, and controlling a phase of the power transmitter with respect to the receiver based on the first power transmitter Power transmission device.
The method of claim 20,

The control unit,

And a power control unit adjacent to the first power transmitter based on the first power transmitter to equally control a phase of a magnetic field.
The method of claim 14,

The control unit,

And determining the reception request power of the reception device, and allocating power to each of the power transmitters based on the transmission efficiency of each power transmitter included in the power transmitter group.
The method of claim 20,

The control unit,

And determining a reception limit power of the reception device, and turning off power of a power transmission unit not included in the power transmission group.
The method of claim 21,

The control unit,

Based on the reception limit power, when the power for wireless power transmission is turned on in the first power transmitter, and the power of the first power transmitter is insufficient to charge the receiver, the first power among the power transmitters; And a power-on unit for power transmission adjacent to the transmission unit.
The method of claim 14,

The control unit,

And controlling the power of the entire power transmitter included in the power transmitter group at once based on the required power of the receiver.
The method of claim 20,

The control unit,

And when the power of the first power transmitter is sufficient to charge the receiver, charging the receiver by using only the first power transmitter.
In the wireless power transmission apparatus,

A charging pad;

A power transmitter included in the charging pad and recognizing a wireless power receiver; and

And a controller configured to control the power transmitter to transmit wireless power to an external device through the power transmitter.

The power transmission unit includes a plurality of stacked coils,

The control unit,

When transmitting wireless power to the external device, the wireless power transmission apparatus, characterized in that for controlling the magnetic field phase of each of the stacked coils.