WO2018124669A1

WO2018124669A1 - Wireless charging method and apparatus and system therefor

Info

Publication number: WO2018124669A1
Application number: PCT/KR2017/015413
Authority: WO
Inventors: 권용일; 유동한
Original assignee: 엘지이노텍 주식회사
Priority date: 2016-12-26
Filing date: 2017-12-22
Publication date: 2018-07-05
Also published as: KR101936180B1; KR20180075342A

Abstract

The present invention relates to wireless power transmission technology, and particularly, to a wireless charging method and an apparatus and a system therefor. A wireless power transmitter according to one embodiment may comprise: a power transmitting unit which comprises at least one transmitting coil; a power conversion unit which converts the intensity of DC power applied from the outside; a communication unit which exchanges information with an external device; and a control unit which transmits a predetermined packet through the communication unit to change a power transmission contract.

Description

Wireless charging method and apparatus and system therefor

TECHNICAL FIELD The present invention relates to wireless power transfer technology, and more particularly, to a wireless charging method and apparatus and system therefor.

Portable terminals such as mobile phones and laptops include a battery that stores power and circuits for charging and discharging the battery. In order for the battery of the terminal to be charged, power must be supplied from an external charger.

In general, as an example of an electrical connection method between a charging device and a battery for charging power to a battery, the terminal is supplied with commercial power and converted into a voltage and a current corresponding to the battery to supply electrical energy to the battery through the terminal of the battery. Supply method. This terminal supply method is accompanied by the use of a physical cable (cable) or wire. Therefore, when handling a lot of terminal supply equipment, many cables occupy considerable working space, are difficult to organize, and are not good in appearance. In addition, the terminal supply method may cause problems such as instantaneous discharge phenomenon due to different potential difference between the terminals, burnout and fire caused by foreign substances, natural discharge, deterioration of battery life and performance.

Recently, in order to solve such a problem, a charging system (hereinafter, referred to as a "wireless charging system") and a control method using a method of transmitting power wirelessly have been proposed. In addition, since the wireless charging system was not pre-installed in some portable terminals in the past and the consumer had to separately purchase a wireless charging receiver accessory, the demand for the wireless charging system was low, but the number of wireless charging users is expected to increase rapidly. It is expected to be equipped with wireless charging function.

In general, the wireless charging system includes a wireless power transmitter for supplying electrical energy through a wireless power transmission method and a wireless power receiver for charging the battery by receiving the electrical energy supplied from the wireless power transmitter.

The wireless charging system may transmit power by at least one wireless power transmission method (eg, electromagnetic induction method, electromagnetic resonance method, RF wireless power transmission method, etc.).

For example, the wireless power transmission scheme may use various wireless power transmission standards based on an electromagnetic induction scheme that generates a magnetic field in the power transmitter coil and charges using an electromagnetic induction principle in which electricity is induced in the receiver coil under the influence of the magnetic field. . Here, the electromagnetic induction wireless power transmission standard may include an electromagnetic induction wireless charging technology defined by the Wireless Power Consortium (WPC) and Air Fuel Alliance (formerly PMA, Power Matters Alliance).

As another example, the wireless power transmission method may use an electromagnetic resonance method of transmitting power to a wireless power receiver located in close proximity by tuning a magnetic field generated by a transmission coil of the wireless power transmitter to a specific resonance frequency. . Here, the electromagnetic resonance method may include a wireless charging technology of the resonance method defined in the Air Fuel Alliance (formerly A4WP, Alliance for Wireless Power) standard mechanism which is a wireless charging technology standard mechanism.

As another example, the wireless power transmission method may use an RF wireless power transmission method that transmits power to a wireless power receiver located at a far distance by putting energy of low power in an RF signal.

On the other hand, as the wireless charging function is installed in various devices and the power intensity required by the wireless power receiver is increased, the wireless power transmitter has increased heat and electromagnetic wave emission by high output. If the temperature increases due to heat generation, the wireless power transmitter may cause problems such as deterioration of wireless power transmission performance or damage to an internal system. In addition, the high electromagnetic waves emitted by the wireless power transmitter may be harmful to the human body, and may cause a problem of Electro Magnetic Compatibility (EMC). As an example of electronic compatibility, the frequency of the wireless charging system and the frequency of the vehicle smart key may cause interference.

The present invention has been devised to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide a wireless charging method and apparatus and system therefor.

Still another object of the present invention is to provide a wireless charging method capable of controlling charging power according to a state of a wireless power transmission apparatus, and an apparatus and system therefor.

Still another object of the present invention is to provide a wireless charging method capable of controlling the charging power of the wireless power transmission apparatus, and an apparatus and system therefor.

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.

In order to solve the above technical problem, the wireless power transmitter according to the embodiment includes a power transmitter including one or more transmission coils; A power converter converting the intensity of DC power applied from the outside; A communication unit exchanging information with an external device; And a controller for changing a power transmission contract by transmitting a predetermined packet through the communication unit.

In addition, in the wireless power transmitter according to the embodiment, the power transmission contract may include guaranteed power which is a power strength value transmitted by the power transmitter in the power transmission step.

In addition, in the wireless power transmitter according to the embodiment, the control unit may collect wireless power transmitter state information and transition to the renegotiation step based on the wireless power transmitter state information.

In addition, in the wireless power transmitter according to the embodiment, the transmitter state information may include a guaranteed power value that can be transmitted by the wireless power transmitter.

In addition, in the wireless power transmitter according to the embodiment, the guaranteed power value may be recorded in a power transmitter capability packet.

In addition, in the wireless power transmitter according to the embodiment, the control unit may transition to a renegotiation step by transmitting a NAK packet after receiving a received power packet.

In addition, the wireless power transmitter according to an embodiment may transmit the power transmitter capability packet after receiving the general request packet.

In addition, in the wireless power transmitter according to the embodiment, the control unit may transmit the power transmitter capability packet after receiving the renegotiation packet.

In addition, the wireless power transmitter according to the embodiment includes a sensing unit for measuring the internal temperature, the electromagnetic wave intensity emitted from the power transmitter or the intensity of the external electromagnetic wave, the control unit is measured internal temperature value, electromagnetic wave intensity value of the sensing unit Alternatively, the renegotiation step may be performed to change the power transmission contract based on the intensity value of the external electromagnetic wave.

According to an embodiment, a wireless power receiver includes a receiving coil; A communication unit exchanging information with an external device through the receiving coil; And a controller for transitioning to a renegotiation step according to the control of the external device.

In addition, the wireless power receiver according to an embodiment may transition to the renegotiation step when the controller transmits a received power packet to the external device and receives a NAK packet from the external device.

In addition, in the wireless power receiver according to the embodiment, the received power packet may be a 24-bit received power packet.

In addition, the wireless power receiver according to an embodiment may transmit the general request packet after receiving the NAK packet.

The wireless power receiver according to the embodiment may receive the power transmitter capability packet after transmitting the general request packet.

In addition, the wireless power receiver according to an embodiment may transmit the renegotiation packet after receiving the NAK packet.

The wireless power receiver according to the embodiment may receive a power transmitter capability packet after transmitting the renegotiation packet.

The wireless charging method according to the embodiment is a wireless charging method in a wireless power transmitter for transmitting power wirelessly to a wireless power receiver, in the power transmission step, the wireless power transmitter is a power to a guaranteed power value according to a power transmission contract Transmitting; The wireless power transmitter collecting transmitter status information; Determining, by the wireless power transmitter, whether a transition is necessary to a renegotiation step based on the collected transmitter state information; And when the renegotiation step is required, transmitting the NAK packet after the reception of the received power packet to transition to the renegotiation step.

The wireless charging method may further include transmitting a power transmitter capability packet when the wireless power transmitter receives the general request packet after the transition to the renegotiation step.

The wireless charging method may further include transmitting a power transmitter capability packet when the wireless power transmitter receives the renegotiation packet after the transition to the renegotiation step.

The wireless charging method may further include determining whether the wireless power transmitter has transitioned to a power transmission step in the renegotiation step.

The wireless charging method according to the embodiment may further include the step of transitioning to the power transmission step by modifying the guaranteed power value of the power transmission contract if it is determined that the transition to the power transmission step. .

In addition, in the wireless charging method according to the embodiment, the power transmission contract may include guaranteed power, which is a power strength value transmitted by the power transmitter in a power transmission step.

In addition, in the wireless charging method according to the embodiment, the transmitter state information may include a guaranteed power value that can be transmitted by the wireless power transmitter.

In addition, in the wireless charging method according to the embodiment, the guaranteed power value may be recorded in a power transmitter capability packet.

A wireless charging method according to an embodiment of the present invention provides a wireless charging method in a wireless power receiver for wirelessly receiving power from a wireless power transmitter, wherein the wireless power receiver comprises: transmitting a received power packet; The wireless power receiver may include the step of transitioning to a renegotiation step by receiving a NAK packet and transmitting a general request packet.

In addition, in the wireless charging method according to the embodiment, the received power packet may be a 24-bit received power packet.

In addition, in the wireless charging method according to the embodiment, the general request packet may be a packet for requesting a power transmitter capability packet from the wireless power transmitter.

In addition, the wireless charging method according to the embodiment may further comprise the step of determining whether the wireless power receiver transitions to the power transmission step in the renegotiation step.

A wireless charging method according to an embodiment of the present invention provides a wireless charging method in a wireless power receiver for wirelessly receiving power from a wireless power transmitter, wherein the wireless power receiver comprises: transmitting a received power packet; The wireless power receiver may include a step of transmitting a renegotiation packet and transitioning to a renegotiation step after receiving the NAK packet.

In addition, the wireless charging method according to the embodiment may further comprise the step of receiving the power transmitter capability packet from the wireless power transmitter after the transition to the renegotiation step.

The effects on the effects of the wireless charging method and apparatus and system therefor according to the present invention are as follows.

The present invention can provide a wireless charging method and apparatus and system therefor.

In addition, the present invention can control the charging power according to the state of the wireless power transmission apparatus.

In addition, in the present invention, the wireless power transmission apparatus may control the charging power.

In addition, the present invention can control the charging power to reduce the heat generation of the wireless power transmission apparatus.

In addition, the present invention can control the charging power to reduce the electromagnetic emission of the wireless power transmission apparatus.

In addition, the present invention can minimize the charging time by increasing the strength of the charging power.

In addition, the present invention can reduce the number of packets exchanged between the wireless power transmitter and the wireless power receiver to perform the renegotiation step, thereby minimizing the renegotiation step time.

In addition, the present invention can have a wider charging area by using a plurality of transmission coils, and thus user convenience is high.

In addition, the present invention can use only one of a plurality of the same circuit can reduce the size of the wireless power transmitter itself, it is possible to reduce the cost of the components used.

In addition, the present invention may utilize component elements defined in the published wireless power transfer standards, which may be in accordance with already defined standards.

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 block diagram illustrating a wireless charging system according to an embodiment.

2 is a block diagram illustrating a wireless charging system according to another embodiment.

3 is a diagram for describing a detection signal transmission procedure in a wireless charging system according to an embodiment.

4 is a state transition diagram for explaining a wireless power transmission procedure defined in the WPC standard.

5 is a state transition diagram for explaining a wireless power transmission procedure defined in the WPC (Qi) standard.

6 is a block diagram illustrating a structure of a wireless power transmitter according to an embodiment.

FIG. 7 is a block diagram illustrating a structure of a wireless power receiver interworking with the wireless power transmitter according to FIG. 6.

8 is a diagram for describing a method of modulating and demodulating a wireless power signal, according to an exemplary embodiment.

9 is a diagram for describing a packet format, according to an exemplary embodiment.

10 is a diagram for describing types of packets transmitted from a wireless power receiver to a wireless power transmitter, according to an embodiment.

11 illustrates a signal strength packet according to a wireless power transmission procedure according to an embodiment.

12 is a diagram for describing a power transmission end packet according to a wireless power transmission procedure according to an embodiment.

FIG. 13 is a diagram for describing a power control suspension packet according to a wireless power transmission procedure according to one embodiment. FIG.

14 illustrates a configuration packet according to a wireless power transmission procedure according to an embodiment.

15 illustrates an identification packet and an extended identification packet according to a wireless power transmission procedure according to an embodiment.

16 illustrates a general request packet according to a wireless power transmission procedure according to an embodiment.

17 illustrates a special request packet according to a wireless power transmission procedure according to an embodiment.

18 is a diagram illustrating a FOD status packet according to a wireless power transmission procedure according to an embodiment.

19 illustrates a control error packet according to a wireless power transmission procedure according to an embodiment.

20 illustrates a renegotiation packet according to a wireless power transmission procedure according to an embodiment.

21 illustrates a message format of an 8-bit received power packet according to a wireless power transmission procedure according to an embodiment.

22 illustrates a 24-bit received power packet according to a wireless power transmission procedure according to an embodiment.

FIG. 23 illustrates a message format of a charging state packet according to a wireless power transmission procedure according to an embodiment.

24 illustrates a packet transmitted from a wireless power transmitter to a wireless power receiver and a power transmitter capability packet according to a wireless power transmission procedure according to an embodiment.

25 is a diagram for describing a wireless charging method on a wireless charging system, according to an exemplary embodiment.

FIG. 26 illustrates a wireless charging method including a renegotiation step on a wireless charging system according to another embodiment.

27 is a diagram for describing a wireless charging method including a renegotiation step on a wireless charging system according to another embodiment.

28 is a diagram for describing a wireless charging method in a wireless power transmitter, according to an embodiment.

29 is a diagram for describing a wireless charging method in a wireless power receiver, according to an embodiment.

30 is a diagram for describing a wireless charging method including a renegotiation step on a wireless charging system according to another embodiment.

FIG. 31 illustrates a wireless charging method including a renegotiation step on a wireless charging system according to another embodiment.

32 is a diagram for describing a wireless charging method of a wireless power transmitter according to another embodiment.

33 is a view for explaining a wireless charging method in a wireless power receiver according to another embodiment.

34 is a diagram illustrating a renegotiation step time in a wireless charging method, according to an embodiment.

35 is a diagram for describing a wireless charging transmission coil, according to an exemplary embodiment.

36 is a diagram for describing three drive circuits including a full-bridge inverter in a wireless power transmitter including a plurality of coils, according to an exemplary embodiment.

37 is a diagram for describing a wireless power transmitter including a plurality of coils and a single drive circuit, according to an exemplary embodiment.

38 is a diagram for describing a plurality of switches connecting one of a plurality of transmission coils to a drive circuit according to an exemplary embodiment.

Hereinafter, an apparatus and various methods to which the embodiments 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 foregoing description, the present invention is not necessarily limited to these embodiments, although all of the components constituting the embodiments are described as being combined or operating in combination. In other words, within the scope of the present invention, all of the components may be selectively operated in combination with one or more. In addition, although all of the components may be implemented in one independent hardware, each or all of the components may be selectively combined to perform some or all functions combined in one or a plurality of hardware. It may be implemented as a computer program having a. Codes and code segments constituting the computer program may be easily inferred by those skilled in the art. Such a computer program may be stored in a computer readable storage medium and read and executed by a computer, thereby implementing the embodiments. The storage medium of the computer program may include a magnetic recording medium, an optical recording medium, a carrier wave medium, and the like.

In the description of the embodiments, in the case of being described as being formed at "up (up) or down (down)", "before (front) or back (back)" of each component, "up (up) or down (Below) "and" before (before) or after (behind) "include both in which the two components are in direct contact with each other or one or more other components are formed disposed between the two components.

In addition, the terms "comprise", "comprise" or "having" described above mean that the corresponding component may be included, unless otherwise stated, and thus excludes other components. It should be construed that it may further include other components instead. All terms, including technical and scientific terms, have the same meanings as commonly understood by one of ordinary skill in the art unless otherwise defined. Terms commonly used, such as terms defined in a dictionary, should be interpreted to coincide with the contextual meaning of the related art, and shall not be construed in an ideal or excessively formal sense unless explicitly defined in the present invention.

In addition, in describing the component of this invention, terms, such as 1st, 2nd, A, B, (a), (b), can be used. These terms are only for distinguishing the components from other components, and the nature, order or order of the components are not limited by the terms. If a component is described as being "connected", "coupled" or "connected" to another component, that component may be directly connected to or connected to that other component, but there may be another configuration between each component. It is to be understood that the elements may be "connected", "coupled" or "connected".

In the following description of the present invention, when it is determined that the subject matter of the present invention may be unnecessarily obscured by those skilled in the art with respect to the related well-known technology, the detailed description thereof will be omitted.

In the description of the embodiment, the apparatus for transmitting wireless power on the wireless power charging system is a wireless power transmitter, wireless power transmitter, wireless power transmitter, wireless power transmitter, transmitter, transmitter, transmitter, transmitting side for convenience of description. A wireless power transmitter, a wireless power transmitter, and a wireless charging device will be used in combination. In addition, as a representation of a device for receiving the wireless power from the wireless power transmitter, for convenience of description, a wireless power receiver, a wireless power receiver, a wireless power receiver, a wireless power receiver, a receiver terminal, a receiver, a receiver, a receiver Terminals and the like may be used interchangeably.

Wireless charging apparatus according to the embodiment may be configured in the form of a pad, a cradle, an access point (AP), a small base station, a stand, a ceiling buried, a wall, etc., one transmitter receives a plurality of wireless power It may also transmit power to the device.

For example, the wireless power transmitter may not only be used on a desk or a table, but also may be developed and applied to an automobile and used in a vehicle. The wireless power transmitter installed in the vehicle may be provided in the form of a cradle that can be fixed and mounted simply and stably.

Terminal according to the embodiment 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), navigation, MP3 player, electric It may be used in small electronic devices such as a toothbrush, an electronic tag, a lighting device, a remote control, a fishing bobber, and the like, but is not limited to this. The term "terminal" or "device" may be used interchangeably. The wireless power receiver according to another embodiment may be mounted in a vehicle, an unmanned aerial vehicle, an air drone, or the like.

The wireless power receiver according to the embodiment may be provided with at least one wireless power transmission scheme, and may simultaneously receive wireless power from two or more wireless power transmitters. Here, the wireless power transmission method may include at least one of the electromagnetic induction method, electromagnetic resonance method, RF wireless power transmission method. In particular, the wireless power receiving means supporting the electromagnetic induction method may include electromagnetic induction wireless charging technology defined by the Wireless Power Consortium (WPC) and Air Fuel Alliance (formerly PMA, Power Matters Alliance). Can be. In addition, the wireless power receiving means supporting the electromagnetic resonance method may include a wireless charging technology of the resonance method defined in the Air Fuel Alliance (formerly A4WP, Alliance for Wireless Power) standard mechanism of the wireless charging technology standard mechanism.

In general, the wireless power transmitter and the wireless power receiver constituting the wireless power system may exchange control signals or information through in-band communication or Bluetooth low energy (BLE) communication. Here, in-band communication and BLE communication may be performed by a pulse width modulation method, a frequency modulation method, a phase modulation method, an amplitude modulation method, an amplitude and phase modulation method, or the like. For example, the wireless power receiver may transmit various control signals and information to the wireless power transmitter by generating a feedback signal by switching ON / OFF the current induced through the receiving coil in a predetermined pattern. The information transmitted by the wireless power receiver may include various state information including received power strength information. In this case, the wireless power transmitter may calculate the charging efficiency or the power transmission efficiency based on the received power strength information.

Referring to FIG. 1, a wireless charging system includes a wireless power transmitter 10 that largely transmits power wirelessly, a wireless power receiver 20 that receives the transmitted power, and an electronic device 30 that receives the received power. Can be configured.

For example, the wireless power transmitter 10 and the wireless power receiver 20 may perform in-band communication for exchanging information using the same frequency band as the operating frequency used for wireless power transmission. In another example, the wireless power transmitter 10 and the wireless power receiver 20 perform out-of-band communication for exchanging information using a separate frequency band different from an operating frequency used for wireless power transmission. It can also be done.

For example, the information exchanged between the wireless power transmitter 10 and the wireless power receiver 20 may include control information as well as status information of each other. Here, the status information and control information exchanged between the transmitting and receiving end will be more clear through the description of the embodiments to be described later.

The in-band communication and the out-of-band communication may provide bidirectional communication, but are not limited thereto. In another embodiment, the in-band communication and the out-of-band communication may provide one-way communication or half-duplex communication.

For example, the unidirectional communication may be performed by the wireless power receiver 20 only transmitting information to the wireless power transmitter 10, but is not limited thereto. The wireless power transmitter 10 may transmit information to the wireless power receiver 20. It may be to transmit.

In the half-duplex communication method, bidirectional communication between the wireless power receiver 20 and the wireless power transmitter 10 is possible, but at one time, only one device may transmit information.

The wireless power receiver 20 according to an embodiment may obtain various state information of the electronic device 30. For example, the state information of the electronic device 30 may include current power usage information, information for identifying a running application, CPU usage information, battery charge status information, battery output voltage / current information, and the like. The information may be obtained from the electronic device 30 and may be utilized for wireless power control.

For example, as illustrated by reference numeral 200a, the wireless power receiver 20 may be configured with a plurality of wireless power receivers, and a plurality of wireless power receivers are connected to one wireless power transmitter 10 so that the wireless Charging may also be performed. In this case, the wireless power transmitter 10 may distribute and transmit power to the plurality of wireless power receivers in a time division manner, but is not limited thereto. As another example, the wireless power transmitter 10 may be configured for each wireless power receiver. By using different allocated frequency bands, power may be distributed and transmitted to a plurality of wireless power receivers.

In this case, the number of wireless power receivers that can be connected to one wireless power transmitter is adapted based on at least one of required power for each wireless power receiver, battery charge state, power consumption of the electronic device, and available power of the wireless power transmitter. Can be determined as

As another example, as illustrated in FIG. 200B, the wireless power transmitter 10 may include a plurality of wireless power transmitters. In this case, the wireless power receiver 20 may be connected to a plurality of wireless power transmitters at the same time, and may simultaneously receive power from the connected wireless power transmitters and perform charging. In this case, the number of wireless power transmitters connected to the wireless power receiver 20 is adaptively based on the required power of the wireless power receiver 20, the state of charge of the battery, the power consumption of the electronic device, the available power of the wireless power transmitter, and the like. Can be determined.

For example, the wireless power transmitter may be equipped with three transmitting

coils

111, 112, and 113. Each transmission coil may overlap some other area with another transmission coil, and the wireless power transmitter may detect a

predetermined detection signal

117, 127 for detecting the presence of the wireless power receiver through each transmission coil, for example, Digital ping signals are sent sequentially in a predefined order.

As shown in FIG. 3, the wireless power transmitter sequentially transmits the detection signal 117 through the primary detection signal transmission procedure illustrated in FIG. 110, and receives a signal strength indicator from the wireless power receiver 115. The strength indicator 116 (or signal strength packet) may identify the received

transmission coils

111, 112. Subsequently, the wireless power transmitter sequentially transmits the detection signal 127 through the secondary detection signal transmission procedure shown in FIG. 120, and transmits power among the transmission coils 111 and 112 where the signal strength indicator 126 is received. The efficiency (or charging efficiency)-that is, the alignment between the transmitting coil and the receiving coil-can identify a good transmitting coil and control that power can be sent through the identified transmitting coil-i.e. wireless charging is made. .

As shown in FIG. 3, the reason why the wireless power transmitter performs two sensing signal transmission procedures is to more accurately identify which transmitting coil is well aligned with the receiving coil of the wireless power receiver.

If the

signal strength indicators

116 and 126 are received at the first transmission coil 111 and the second transmission coil 112, as shown in the

reference numerals

110 and 120 of FIG. 3, the wireless power transmitter. Based on the signal strength indicator 126 received at each of the first transmitting coil 111 and the second transmitting coil 112 selects the best-aligned transmitting coil and performs wireless charging using the selected transmitting coil. .

Referring to FIG. 4, power transmission from a transmitter to a receiver according to the WPC standard is largely selected from a selection phase 410, a ping phase 420, an identification and configuration phase 430, It may be divided into a power transfer phase 440.

The selection step 410 may be a step of transitioning when a specific error or a specific event is detected while starting or maintaining the power transmission. Here, specific errors and specific events will be apparent from the following description. In addition, in the selection step 410, the transmitter may monitor whether an object exists on the interface surface. If the transmitter detects that an object is placed on the interface surface, it may transition to the ping step 420 (S401). In the selection step 410, the transmitter transmits a very short pulse of an analog ping signal, and may detect whether an object exists in an active area of the interface surface based on a change in current of a transmitting coil.

In ping step 420, when an object is detected, the transmitter activates the receiver and sends a digital ping to identify whether the receiver is a receiver that is compliant with the WPC standard. If the transmitter does not receive a response signal (for example, a signal strength indicator) from the receiver in response to the digital ping in step 420, it may transition back to the selection step 410 (S402). In addition, in the ping step 420, when the transmitter receives a signal indicating that power transmission is completed, that is, a charging completion signal, from the receiver, the transmitter may transition to the selection step 410 (S403).

When the ping step 420 is completed, the transmitter may transition to the identification and configuration step 430 for collecting receiver identification and receiver configuration and status information (S404).

In the identification and configuration step 430, the transmitter receives an unexpected packet, a desired packet has not been received for a predefined time, a packet transmission error, or a power transmission contract. If this is not set (no power transfer contract) it may transition to the selection step (410) (S405).

When identification and configuration of the receiver is completed, the transmitter may transition to a power transmission step 440 for transmitting wireless power (S406).

In the power transfer step 440, the transmitter receives an unexpected packet, the desired packet has not been received for a predefined time, or a violation of a preset power transfer contract occurs. transfer contract violation), if the filling is completed, the transition to the selection step (410) (S407).

In addition, in the power transmission step 440, if it is necessary to reconfigure the power transmission contract in accordance with the change in the transmitter state, the transmitter may transition to the identification and configuration step 430 (S408).

The power transmission contract may be set based on state and characteristic information of the transmitter and the receiver. For example, the transmitter state information may include information about the maximum amount of power that can be transmitted, information about the maximum number of receivers that can be accommodated, and the receiver state information may include information about required power.

Referring to FIG. 5, power transmission from a transmitter to a receiver according to the WPC (Qi) standard is largely selected as a selection phase 510, a ping phase 520, an identification and configuration phase, and so on. 530, a negotiation phase 540, a calibration phase 550, a power transfer phase 560, and a renegotiation phase 570.

The selection step 510 may be a transition step, for example, S502, S504, S507, S510, and S512 when a specific error or a specific event is detected while starting or maintaining power transmission. Here, specific errors and specific events will be apparent from the following description. In addition, in the selection step 510, the transmitter may monitor whether an object exists on the interface surface. If the transmitter detects that an object is placed on the interface surface, the transmitter may transition to the ping step 520 (S501). In the selection step 510, the transmitter transmits a very short pulse of an analog ping signal and an object in the active area of the interface surface based on the current change of the transmitting coil or the primary coil. Can detect the presence of

In ping step 520, when an object is detected, the transmitter activates the receiver and sends a digital ping to identify whether the receiver is a receiver that is compliant with the WPC standard. If the transmitter does not receive a response signal (eg, a signal strength packet) for the digital ping from the receiver in the ping step 520, it may transition back to the selection step 510 (S502). In addition, in the ping step 520, when the transmitter receives a signal indicating that power transmission is completed, that is, a charging completion packet, it may transition to the selection step 510 (S502).

When the ping step 520 is completed, the transmitter may transition to the identification and configuration step 530 for identifying the receiver and collecting receiver configuration and status information (S503).

In the identification and configuration step 530, the transmitter receives an unexpected packet, a desired packet has not been received for a predefined time, a packet transmission error, or a power transmission contract. If this is not set (no power transfer contract) it may transition to the selection step (510) (S504).

The transmitter may determine whether entry into the negotiation step 540 is necessary based on a negotiation field value of the configuration packet received in the identification and configuration step 530.

As a result of the check, if negotiation is necessary, the transmitter may enter a negotiation step 540 to perform a predetermined FOD detection procedure and make a power transmission contract (S505).

On the other hand, if it is determined that negotiation is not necessary, the transmitter may immediately enter the power transmission step 560 (S506).

In negotiation step 540, the wireless power transmitter and the wireless power receiver may make a power transmission contract. The power transmission contract may be set based on state and characteristic information of the transmitter and the receiver. For example, the transmitter state information may include information about the maximum amount of power that can be transmitted, information about the maximum number of receivers that can be accommodated, and the receiver state information may include information about required power.

In addition, the power transfer agreement may include guaranteed power. The guaranteed power of the power transmission contract may be a power intensity value determined by the wireless power transmitter and the wireless power receiver to transmit during wireless charging in the power transmission phase. The guaranteed power of the power transfer agreement may have a default value. In addition, the guaranteed power of the power transmission contract can be determined based on the guaranteed power of the wireless power transmitter and the required power of the wireless power receiver. A detailed description of determining the guaranteed power of a power transmission contract will be given later. Note that there is a difference between the guaranteed power of the power transmission contract and the guaranteed power of the wireless power transmitter. That is, the guaranteed power of the power transmission contract may be a power intensity value transmitted in the power transmission step, and the guaranteed power of the wireless power transmitter may be a power intensity value that the wireless power transmitter can transmit. The guaranteed power of the wireless power transmitter may be information recorded in the power transmitter capability packet, which will be described later.

In addition, in the negotiation step 540, the transmitter may receive a Foreign Object Detection (FOD) status packet including a reference quality factor value. In this case, the transmitter may determine a threshold for FO detection based on the reference quality factor value.

The transmitter may detect whether the FO exists in the charging region by using the determined threshold for FO detection and the currently measured quality factor value, and control power transmission according to the FO detection result. For example, when the FO is detected, power transmission may be stopped, but is not limited thereto.

If the FO is detected, the transmitter may return to the selection step 510 (S507). On the other hand, when the FO is not detected, the transmitter may enter the power transmission step 560 through the correction step 550 (S508) (S509). In detail, when the FO is not detected, the transmitter determines the strength of the power received at the receiving end in the correction step 550, and determines the power loss at the receiving end and the transmitting end to determine the strength of the power transmitted by the transmitting end. It can be measured. That is, the transmitter may predict the power loss based on the difference between the transmit power of the transmitter and the receive power of the receiver in the correction step 550. The transmitter according to an embodiment may correct the threshold for FOD detection by reflecting the predicted power loss.

In power transmission step 540, the transmitter receives an unexpected packet, an outgoing desired packet for a predefined time, or a violation of a predetermined power transmission contract occurs. transfer contract violation), if the filling is complete, the transition to the selection step (510) (S510).

In addition, in the power transmission step 540, if it is necessary to reconfigure the power transmission contract according to the change in the transmitter state, the transmitter may transition to the renegotiation step 570 (S511).

In the renegotiation step 570, if the renegotiation such as a power transmission contract is normally completed, the transmitter may return to the power transmission step 560 (S513). Further, in the renegotiation step 570, the transmitter receives an unexpected packet, a desired packet has not been received for a predefined time, or a violation of a preset power transmission contract occurs ( power transfer contract violation), if the charging is completed, the transition to the selection step (510) (S512).

Referring to FIG. 6, the wireless power transmitter 600 may largely include a power converter 610, a power transmitter 620, a communication unit 630, a controller 640, and a sensor 650. . It should be noted that the configuration of the wireless power transmitter 600 is not necessarily an essential configuration, and may include more or fewer components.

As shown in FIG. 6, when power is supplied from the power supply unit 660, the power converter 610 may perform a function of converting the power into power of a predetermined intensity.

To this end, the power converter 610 may include a DC / DC converter 611 and an amplifier 612.

The DC / DC converter 611 may perform a function of converting DC power supplied from the power supply unit 660 into DC power having a specific intensity according to a control signal of the controller 640.

In this case, the sensing unit 650 may measure the voltage / current of the DC-converted power and provide the same to the control unit 640. In addition, the sensing unit 650 may measure the internal temperature of the wireless power transmitter 600 to determine whether overheating occurs, and provide the measurement result to the controller 640. In addition, the sensing unit 650 may measure the electromagnetic wave intensity radiated from the power transmitter 620 to determine whether the electromagnetic wave is over-radiated, and provide the measurement result to the controller 640. In addition, the sensing unit 650 may measure the intensity and frequency of the external electromagnetic wave of the wireless power transmitter 600 and determine the electromagnetic interference, and may provide the measurement result to the controller 640.

The controller 640 adaptively supplies power from the power supply unit 650 based on the transmitter state information, the voltage / current value measured by the sensing unit 650, the internal temperature value, the electromagnetic wave value, the intensity and frequency of the external electromagnetic wave, and the like. Block the power supply to the amplifier 612. To this end, one side of the power converter 610 may be further provided with a predetermined power cut-off circuit for cutting off the power supplied from the power supply unit 650, or cut off the power supplied to the amplifier 612.

In addition, the control unit 640 and the wireless power receiver based on the transmitter status information, the voltage / current value, the internal temperature value, the electromagnetic wave intensity value, the intensity and frequency of the external electromagnetic wave measured in the power transmission step The renegotiation phase can be performed to modify the power transfer agreement. To this end, the controller 640 may generate a predetermined packet for performing the renegotiation step and transmit the predetermined packet to the modulator 631. The signal modulated by the modulator 631 may be transmitted to the wireless power receiver through the transmitting coil 622 or a separate coil (not shown). For example, the controller 640 may perform a renegotiation step by transmitting a NAK packet after receiving a received power packet. The amplifier 612 may adjust the intensity of the DC / DC converted power according to the control signal of the controller 640. For example, the controller 640 may receive power reception state information or (and) power control signal of the wireless power receiver through the communication unit 630, and may be based on the received power reception state information or (and) power control signal. The amplification factor of the amplifier 612 can be dynamically adjusted. For example, the power reception state information may include, but is not limited to, strength information of the rectifier output voltage and strength information of a current applied to the receiving coil. The power control signal may include a signal for requesting power increase, a signal for requesting power reduction, and the like.

The power transmitter 620 may include a multiplexer 621 (or a multiplexer) and a transmission coil 622. In addition, the power transmitter 620 may further include a carrier generator (not shown) for generating a specific operating frequency for power transmission.

The carrier generator may generate a specific frequency for converting the output DC power of the amplifier 612 received through the multiplexer 621 into AC power having a specific frequency. In the above description, the AC signal generated by the carrier generator is mixed with the output terminal of the multiplexer 621 to generate AC power. However, this is only one embodiment, and the other example is before the amplifier 612. Note that it may be mixed in stages or later.

Frequency of AC power delivered to each transmission coil according to one embodiment may be different from each other, and another embodiment each using a predetermined frequency controller with a function to adjust the LC resonance characteristics differently for each transmission coil It is also possible to set different resonant frequencies for each transmission coil.

However, when the resonant frequencies generated in each of the plurality of transmitting coils are different, a separate frequency controller for controlling the same may be required, thereby increasing the size of the wireless power transmitter. 35 to 37 illustrate a case in which power is transmitted using the same resonant frequency, even if including.

As shown in FIG. 6, the power transmitter 620 includes a multiplexer 621 and a plurality of transmit coils 622—that is, a first to control the output power of the amplifier 612 to be transmitted to the transmit coil. To n-th transmission coils.

When a plurality of wireless power receivers are connected, the controller 640 according to an embodiment may transmit power through time division multiplexing for each transmission coil. For example, three wireless power receivers, i.e., the first through third wireless power receivers, are identified in the wireless power transmitter 600 through three different transmission coils, i.e., the first through third transmission coils. In this case, the controller 640 may control the multiplexer 621 to control power to be transmitted through a specific transmission coil in a specific time slot. In this case, the amount of power transmitted to the corresponding wireless power receiver may be controlled according to the length of the time slot allocated to each transmitting coil, but this is only one embodiment. By controlling the amplification factor of the amplifier 612 of the wireless power receiver may be controlled to transmit power.

The controller 640 may control the multiplexer 621 to sequentially transmit the sensing signals through the first to nth transmitting coils 622 during the first sensing signal transmission procedure. In this case, the controller 640 may identify a time point at which the detection signal is transmitted by using the timer 655. When the detection signal transmission time arrives, the control unit 640 controls the multiplexer 621 to detect the detection signal through the corresponding transmission coil. Can be controlled to be sent. For example, the timer 650 may transmit a specific event signal to the controller 640 at a predetermined period during the ping transmission step. When the corresponding event signal is detected, the controller 640 controls the multiplexer 621 to transmit the specific event signal. The digital ping can be sent through the coil.

In addition, the control unit 640 stores a predetermined transmission coil identifier and a corresponding transmission coil for identifying which transmission coil has received a signal strength indicator from the demodulator 632 during the first detection signal transmission procedure. Signal strength indicator received through the can be received. Subsequently, in the second detection signal transmission procedure, the control unit 640 controls the multiplexer 621 so that the detection signal may be transmitted only through the transmission coil (s) in which the signal strength indicator was received during the first detection signal transmission procedure. You may. As another example, the controller 640 transmits the second sensed signal to the transmit coil in which the signal strength indicator having the largest value is received when there are a plurality of transmit coils in which the signal intensity indicator is received during the first sensed signal transmit procedure. In the procedure, the sensing signal may be determined as the transmitting coil to be transmitted first, and the multiplexer 621 may be controlled according to the determination result.

The modulator 631 may modulate the control signal generated by the controller 640 and transmit the modulated control signal to the multiplexer 621. Here, the modulation scheme for modulating the control signal is a frequency shift keying (FSK) modulation scheme, a Manchester coding modulation scheme, a PSK (Phase Shift Keying) modulation scheme, a pulse width modulation scheme, a differential 2 Differential bi-phase modulation schemes may be included, but is not limited thereto.

When a signal received through the transmitting coil is detected, the demodulator 632 may demodulate the detected signal and transmit the demodulated signal to the controller 640. Here, the demodulated signal may include a signal strength indicator, an error correction (EC) indicator for controlling power during wireless power transmission, an end of charge (EOC) indicator, an overvoltage / overcurrent / overheat indicator, and the like. However, the present invention is not limited thereto, and may include various state information for identifying a state of the wireless power receiver.

In addition, the demodulator 632 may identify from which transmission coil the demodulated signal is received, and may provide the control unit 640 with a predetermined transmission coil identifier corresponding to the identified transmission coil.

For example, the wireless power transmitter 600 may obtain the signal strength indicator through in-band communication that communicates with the wireless power receiver using the same frequency used for wireless power transmission.

In addition, the wireless power transmitter 600 may not only transmit wireless power using the transmission coil 622 but also exchange various information with the wireless power receiver through the transmission coil 622. As another example, the wireless power transmitter 600 further includes a separate coil corresponding to each of the transmission coils 622 (that is, the first to nth transmission coils), and wireless power using the separate coils provided. Note that in-band communication with the receiver may also be performed.

In the description of FIG. 6, the wireless power transmitter 600 and the wireless power receiver perform in-band communication by way of example. However, this is only one embodiment, and is a frequency band used for wireless power signal transmission. Short-range bidirectional communication may be performed through a frequency band different from that of FIG. For example, the short-range bidirectional communication may be any one of low power Bluetooth communication, RFID communication, UWB communication, and Zigbee communication.

Referring to FIG. 7, the wireless power receiver 700 includes a receiving coil 710, a rectifier 720, a DC / DC converter 730, a load 740, a sensing unit 750, and a communication unit ( 760), and may include a main controller 770. Herein, the communication unit 760 may include at least one of a demodulator 761 and a modulator 762.

Although the wireless power receiver 700 illustrated in the example of FIG. 7 is illustrated as being capable of exchanging information with the wireless power transmitter 600 through in-band communication, this is only one embodiment. The communication unit 760 according to the embodiment may provide short-range bidirectional communication through a frequency band different from the frequency band used for wireless power signal transmission.

AC power received through the receiving coil 710 may be delivered to the rectifier 720. The rectifier 720 may convert AC power into DC power and transmit the DC power to the DC / DC converter 730. The DC / DC converter 730 may convert the strength of the rectifier output DC power into a specific intensity required by the load 740 and then transfer it to the load 740. In addition, the receiving coil 710 may include a plurality of receiving coils (not shown), that is, the first to nth receiving coils. Frequency of AC power delivered to each receiving coil (not shown) according to one embodiment may be different from each other, another embodiment is a predetermined frequency controller with a function to adjust the LC resonance characteristics differently for each receiving coil It is also possible to set a different resonant frequency for each receiving coil by using a.

The sensing unit 750 may measure the intensity of the rectifier 720 output DC power and provide the same to the main controller 770. In addition, the sensing unit 750 may measure the strength of the current applied to the receiving coil 710 according to the wireless power reception, and may transmit the measurement result to the main controller 770. In addition, the sensing unit 750 may measure the internal temperature of the wireless power receiver 700 and provide the measured temperature value to the main controller 770.

For example, the main controller 770 may determine whether the overvoltage occurs by comparing the measured intensity of the rectifier output DC power with a predetermined reference value. As a result of the determination, when the overvoltage is generated, a predetermined packet indicating that the overvoltage has occurred may be generated and transmitted to the modulator 762. Here, the signal modulated by the modulator 762 may be transmitted to the wireless power transmitter through the receiving coil 710 or a separate coil (not shown). In addition, when the intensity of the rectifier output DC power is greater than or equal to a predetermined reference value, the main controller 770 may determine that a sensing signal has been received. When the sensing signal is received, a signal strength indicator corresponding to the sensing signal may be modulated. Can be transmitted to the wireless power transmitter. As another example, the demodulator 761 demodulates an AC power signal or a rectifier 720 output DC power signal between the receiving coil 710 and the rectifier 720 to identify whether a detection signal is received, and then, the main subject of the identification result. It may be provided to the unit 770. In this case, the main controller 770 may control the signal strength indicator corresponding to the sensing signal to be transmitted through the modulator 762.

In addition, the main controller 770 may generate a predetermined packet for performing the renegotiation step and transmit the predetermined packet to the modulator 762. The signal modulated by the modulator 762 may be transmitted to the wireless power receiver through the transmission coil 710 or a separate coil (not shown). For example, when the main controller 770 receives the NAK packet after transmitting the received power packet, the main controller 770 may generate a general request packet for the power transmitter capability packet request and transmit the generated request packet to the modulator 762. As another example, when the main control unit 770 receives the NAK packet after transmitting the received power packet, the main control unit 770 may generate a renegotiation packet and transmit it to the modulator 762.

As shown in reference numeral 810 of FIG. 8, the wireless power transmitter 10 and the wireless power receiver 20 may encode or decode a transmission target packet based on an internal clock signal having the same period.

Hereinafter, a method of encoding a transmission target packet will be described in detail with reference to FIGS. 1 to 8.

Referring to FIG. 1, when the wireless power transmitter 10 or the wireless power receiver 20 does not transmit a specific packet, the wireless power signal is modulated with a specific frequency, as shown by reference numeral 41 of FIG. 1. AC signal may not be. On the other hand, when the wireless power transmitter 10 or the wireless power receiver 20 transmits a specific packet, the wireless power signal may be an AC signal modulated by a specific modulation scheme as shown in FIG. For example, the modulation scheme may include, but is not limited to, an amplitude modulation scheme, a frequency modulation scheme, a frequency and amplitude modulation scheme, a phase modulation scheme, and the like.

Differential bi-phase encoding may be applied to binary data of a packet generated by the wireless power transmitter 10 or the wireless power receiver 20 as shown in FIG. Specifically, differential two-stage encoding allows two state transitions to encode data bit 1 and one state transition to encode data bit zero. That is, data bit 1 is encoded such that a transition between a HI state and a LO state occurs at a rising edge and a falling edge of the clock signal, and data bit 0 is HI at the rising edge of the clock signal. The transition between state and LO state may be encoded to occur.

The encoded binary data may be applied with a byte encoding scheme, as shown at 830. Referring to FIG. 830, the byte encoding scheme according to an embodiment includes a start bit and a stop bit for identifying a start and type of a corresponding bit stream for an 8-bit encoded binary bit stream. The method may be a method of inserting a parity bit for detecting whether an error of a corresponding bit stream (byte) occurs.

Referring to FIG. 9, a packet format 900 used for information exchange between the wireless power transmitter 10 and the wireless power receiver 20 may be used for acquiring synchronization for demodulating the packet and identifying the correct start bit of the packet. Preamble (910) field, a header (Header, 920) field for identifying the type of the message included in the packet, a message for transmitting the contents (or payload) of the packet (Message, 930) and a checksum (940) field for checking whether an error has occurred in the corresponding packet.

The packet receiver may identify the size of the message 930 included in the packet based on the header 920 value.

In addition, the header 920 may be defined in each step of the wireless power transfer procedure, and in some, the same value may be defined in different steps of the header 920. For example, referring to FIGS. 10 and 24, a 24-bit received power packet transmitted by the wireless power transmitter and a power transmitter capability packet transmitted by the wireless power transmitter correspond to each other. Note that the header value may be equal to 0x31.

The message 930 includes data to be transmitted at the transmitting end of the packet. For example, the data included in the message 930 field may be a report, a request, or a response to the counterpart, but is not limited thereto.

The packet 900 according to another embodiment of the present invention may further include at least one of a transmitter identification information for identifying a transmitter that transmitted the packet and a receiver identification information for identifying a receiver for receiving the packet. Here, the transmitter identification information and the receiver identification information may include IP address information, MAC address information, product identification information, and the like, but are not limited thereto and may be information capable of distinguishing a receiver and a transmitter from a wireless charging system.

The packet 900 according to another embodiment of the present invention may further include predetermined group identification information for identifying the corresponding reception group when the packet is to be received by a plurality of devices.

Referring to FIG. 10, a packet transmitted from a wireless power receiver to a wireless power transmitter includes a signal strength packet for transmitting strength information of a detected ping signal, and power transmission termination for requesting the transmitter to stop power transmission. (End Power Transfer) packet, power control hold-off packet for transmitting time information waiting to adjust actual power after receiving control error packet for transmitting power control, transmitting configuration information of receiver Configuration packet for transmission, identification packet for transmitting receiver identification information and extended identification packet, general request packet for transmitting general request message, and special request message for transmission. Special Request packet for sending, FOD Status packet for sending reference quality factor values for FO detection A control error packet for controlling the transmission power of the transmitter, a renegotiate packet for initiating renegotiation, a 24-bit received power packet for transmitting strength information of received power, and 8 It may include a 8-bit Received Power packet and a Charge Status packet for transmitting the charging status information of the current load.

Packets transmitted from the wireless power receiver to the wireless power transmitter may be transmitted using in-band communication using the same frequency band as the frequency band used for wireless power transmission.

Referring to FIG. 11, a message format of a signal strength packet 1101 may be configured as a signal strength value having a size of 1 byte. The signal strength value may indicate a degree of coupling between the transmitting coil and the receiving coil, and is calculated based on the rectifier output voltage in the digital ping period, the open circuit voltage measured by the output disconnect switch, the intensity of the received power, and the like. It may be a value. The signal strength value may range from a minimum of 0 to a maximum of 255, and may have a value of 255 when the actual measured value U for a particular variable is equal to the maximum value Umax of the variable.

As an example, the signal strength value may be calculated as U / Umax * 256.

Referring to FIG. 12, the message format of the power transmission end packet 1201 according to an embodiment may be configured as an end power transfer code having a size of 1 byte.

The reason why the wireless power receiver requests the wireless power transmitter to terminate the power transmission is because of charge completion, internal fault, over temperature, over voltage, over current, and battery. It may include, but is not limited to, Battery Failure, Reconfigure and No Response, and Noise Current. It should be noted that the power transfer abort code may be further defined for each new power transfer termination reason.

The charging completion may be used that the charging of the receiver battery is completed. Internal errors can be used when a software or logical error in receiver internal operation is detected.

The overheat / overvoltage / overcurrent can be used when the temperature / voltage / current values measured at the receiver exceed the thresholds defined for each.

Battery damage can be used if it is determined that a problem has occurred with the receiver battery.

Reconfiguration can be used when renegotiation for power transfer conditions is required.

No response may be used if it is determined that the transmitter's response to the control error packet, i.e., to increase or decrease the power strength, is not normal.

Unlike the overcurrent, the noise current is a noise generated when switching in the inverter and may be used when the noise current value measured at the receiver exceeds a defined threshold value.

Referring to FIG. 13, the message format of the power control hold packet 1301 may include a power control hold time (T_delay; Power Control Hole-Off Time). A plurality of power control hold packets 1301 may be transmitted during the identification and configuration phase. For example, up to seven power control suspension packets 1301 may be transmitted. The power control hold time T_delay may have a value between a predefined power control hold minimum time T_min: 5 ms and a power control hold maximum time T_max: 205 ms. The apparatus for transmitting power wirelessly may perform power control by using the power control holding time of the power control holding packet 1301 last received in the identifying and configuring step. In addition, the wireless power transmitter may use the T_min value as the T_delay value when the power control hold packet 1301 is not received in the identification and configuration steps.

The power control holding time may refer to a time during which the wireless power transmitter waits without performing power control after receiving the most recent control error packet and before performing the actual power control.

Referring to FIG. 14, the message format of the configuration packet 1401 may have a length of 5 bytes, and includes a power class field, a maximum power field, a power control field, and zero. ) Field, count field, window size field, window offset field, negotiation field, polarity field, depth field, and the like. .

The power class assigned to the wireless power receiver may be recorded in the power class field.

In the maximum power field, the strength value of the maximum power that can be provided by the rectifier output of the wireless power receiver may be recorded.

For example, when the power class is a and the maximum power is b, the maximum power Pmax desired to be provided at the rectifier output of the wireless power receiver may be calculated as (b / 2) * 10 ^ a.

The power control field may be used to indicate according to which algorithm the power control in the wireless power transmitter should be made. For example, if the power control field value is 0, this means that the power control algorithm is defined in the standard, and if the power control field value is 1, it may mean that power control is performed according to an algorithm defined by the manufacturer.

The count field may be used to record the number of option configuration packets to be transmitted by the wireless power receiver in the identification and configuration steps.

The window size field may be used to record the window size for calculating the average received power. As an example, the window size may be a positive integer value greater than 0 and having a unit of 4 ms.

The window offset field may record information for identifying the time from the end of the average received power calculation window to the start of the transmission of the next received power packet. As an example, the window offset may be a positive integer value greater than 0 and having a unit of 4 ms.

If the Negotiation field is 1, the wireless power transmitter sends an ACK response indicating that the wireless power receiver is entering the negotiation phase.

The polarity field can determine the polarity of the FSK. For example, a polarity field value of 1 indicates that the wireless power transmitter uses the default FSK polarity. A zero polarity field indicates that the wireless power transmitter uses reverse FSK polarity.

The depth field allows you to select the FSK modulation depth.

Referring to FIG. 15, the message format of the identification packet 1501 includes a version information field, a manufacturer information field, an extension indicator field, and a basic device identification information field. It may be configured to include.

In the version information field, revision version information of a standard applied to a corresponding wireless power receiver may be recorded.

In the manufacturer information field, a predetermined identification code for identifying the manufacturer who manufactured the corresponding wireless power receiver may be recorded.

The extension indicator field may be an indicator for identifying whether there is an extension identification packet 1502 including extension device identification information. For example, if the extension indicator value is 0, it may mean that there is no extension identification packet. If the extension indicator value is 1, it may mean that the extension identification packet is present after the identification packet.

Referring to reference numerals 1501 to 1502, if the extension indicator value is 0, the device identifier for the corresponding wireless power receiver may be a combination of manufacturer information and basic device identification information. On the other hand, if the extended indicator value is 1, the device identifier for the corresponding wireless power receiver may be a combination of manufacturer information, basic device identification information and extended device identification information.

Referring to FIG. 16, the message format of the general request packet 1601 may include a request field.

The request field may be used for the wireless power receiver to request certain information from the wireless power transmitter. For example, the request field may be set to 0x31 to request a power transmitter capability packet of the wireless power transmitter.

The general request packet 1601 may be transmitted if a change in the power transmission contract or the power transmission contract is required.

For example, the wireless power receiver may transmit a general request packet 1601 for a power transmission contract in a negotiation step.

As another example, the wireless power transmission apparatus may determine that the power transmission contract needs to be changed in the power transmission step. In this case, the wireless power transmitter may transmit the NAK packet in response to the reception of the received power packet. Thereafter, the wireless power receiver receiving the NAK packet may transmit the general request packet 1601 to the wireless power transmitter to perform the renegotiation step.

Referring to FIG. 17, the message format of the special request packet 1701 may include a request field and a request parameter field.

The request field may record information about a parameter to be changed.

In the request parameter field, a change value of a parameter designated by the request field may be recorded.

For example, referring to reference numeral 1702, when a change in count, which is a parameter of a power transmission contract, is required in the negotiation step, the wireless power receiver records 0x00 in the request field and records the change count, that is, the number of counts in the request parameter field. Can be recorded and transmitted. In addition, in order to terminate the negotiation phase or the renegotiation phase for the power transmission contract, the wireless power receiver may record 0x00 in the request field and transmit it. That is, when the request field is 0x00, not only the count of the power transmission contract is changed but also the negotiation phase or the renegotiation phase may be terminated. In addition, if a change in the guaranteed power value, which is a parameter of the power transmission contract, is required, the wireless power receiver may record 0x01 in the request field and record and transmit the guaranteed power value in the request parameter field. In addition, when a 24 bit received power packet is to be used in the power transmission step, the wireless power receiver may record 0x02 in the request field and record the header of the 24 bit received power packet in the request parameter field and transmit the packet.

Referring to FIG. 18, the message format of the FOD status packet 1801 may include a mode field and a reference quality factor value field.

The mode field may be used to indicate an operation mode of the wireless power receiver to which the reference quality factor value is applied. For example, if the mode field is '00', the wireless power receiver may be in a power off state.

The reference quality factor value field may record the reference quality factor value used to determine a threshold for FO detection in the negotiation phase.

Referring to FIG. 19, the message format of the control error packet 1901 may include a control error value field of 1 byte.

The control error value field may record a control error value. The control error value may be an integer value ranging from -128 to +127. If the control error value is negative, the power output of the wireless power transmitter may be lowered. If the control error value is negative, the power output of the wireless power transmitter may increase. If the control error value is 0, the transmission power of the wireless power transmitter may not be raised or lowered. In particular, a control error packet (CEP) having a control error value of 0 may be referred to as a stable control error packet.

In addition, the control error packet 1901 may be transmitted by the wireless power receiver during the power transmission step.

Referring to FIG. 20, the message format of the renegotiation packet 2001 may include a reserved field preset to an arbitrary value. As an example, the reserved field may be set to zero.

The renegotiation packet 2001 may be transmitted if a change in the power transmission contract is required in the power transmission phase.

For example, the wireless power receiver may determine that the power transmission contract needs to be changed in the power transmission step. In this case, the wireless power receiver may transmit the renegotiation packet 2001 to the wireless power transmitter to perform the renegotiation step.

As another example, the wireless power transmission apparatus may determine that the power transmission contract needs to be changed in the power transmission step. In this case, the wireless power transmitter may transmit the NAK packet in response to the reception of the received power packet. Thereafter, the wireless power receiver receiving the NAK packet may transmit the renegotiation packet 2001 to the wireless power transmitter to perform the renegotiation step.

21 illustrates an 8-bit received power packet according to a wireless power transmission procedure according to an embodiment.

Referring to FIG. 21, a message format of an 8-bit received power packet 2101 may include a received power value field of 1 byte.

The reception power value field may record a reception power value. The received power value may correspond to the average rectifier received power value calculated during the predetermined period. Actually received power (Preceived) may be calculated based on the maximum power (Power Class) and the power (Maximum Power) included in the configuration packet. For example, the actual received power may be calculated by (received power value / 128) * (maximum power / 2) * (10 ^ power rating).

Referring to FIG. 22, a message format of a 24-bit received power packet 2201 may include a mode field of 1 byte and a received power value field of 2 bytes.

The mode field may be used to provide additional information about the received power value. In addition, the mode field may be used to request a response of the wireless power transmitter to the reception of the 24-bit received power packet 2291. For example, when the mode field is '000', '001', or '010', the wireless power receiver may request a response to the reception of the 24-bit received power packet 2201 from the wireless power transmitter. In this case, the wireless power transmitter may transmit a NAK packet or an ACK packet to the wireless power receiver. When the mode field is '100', the wireless power receiver may not request a response to the reception of the 24-bit received power packet 2201 from the wireless power transmitter. In this case, the wireless power transmitter may not transmit the NAK packet or the ACK packet to the wireless power receiver.

The reception power value field may record a reception power value. The received power value may correspond to the average rectifier received power value calculated during the predetermined period. Actually received power (Preceived) may be calculated by the wireless power transmission apparatus based on the maximum power (Maximum Power) included in the power transmission contract. As an example, the actual received power Preceived may be calculated by (receive power value / 32768) * (maximum power).

23 is a diagram for describing a charging state packet according to a wireless power transmission procedure according to an embodiment.

Referring to FIG. 23, the message format of the charge status packet 2301 may include a charge status value field of 1 byte.

The charge state value field may record a charge state value. The charge state value may indicate a battery charge of the wireless power receiver. For example, the charge state value 0 may mean a fully discharged state, the charge state value 50 may indicate a 50% charge state, and the charge state value 100 may mean a full state. If the wireless power receiver does not include the rechargeable battery or cannot provide the charging status information, the charging status value may be set to OxFF.

Referring to FIG. 24, a packet 2401 transmitted from a wireless power transmitter to a wireless power receiver may include a power transmitter capability packet 2402 for confirming power that can be transmitted by the transmitter.

The packet 2401 transmitted from the wireless power transmitter to the wireless power receiver may be transmitted using in-band communication using the same frequency band as the frequency band used for wireless power transmission.

The message format of the power transmitter capability packet 2402 includes a Power Class field, a Guaranteed Power Value field, a Potential Power Value field, a WPID field, and a Not Res sens field. Can be configured.

The power rating may be set to '00'.

The guaranteed power value may be transmission power that the wireless power transmitter can transmit according to the state. That is, the guaranteed power value may be a variation value that may vary depending on the state of the wireless power transmitter. For example, when multiple transmitters share a single power supply, the energy provided by a single power supply is limited, so the guaranteed power value depends on the number of wireless power receivers that the wireless power transmitter provides power at the same time. Can be.

The potential power value may be outgoing power that the wireless power transmitter is designed to deliver. That is, the potential power value may be a unique value determined according to the wireless power transmitter design regardless of the state of the wireless power transmitter. As an example, if multiple transmitters share a single power supply, the potential power value may not depend on the number of wireless power receivers for which the wireless power transmitter provides power at the same time.

The power transmitter capability packet 2402 may be transmitted if a change in the power transfer contract or power transfer contract is required.

For example, when the wireless power transmitter receives the general request packet for requesting the power transmitter capability packet 2402, the wireless power transmitter may transmit the power transmitter capability packet 2402 to the wireless power receiver.

As another example, when the wireless power transmitter receives the renegotiation packet, the wireless power transmitter may transmit the power transmitter capability packet 2402 to the wireless power receiver. More specifically, the wireless power transmitter may enter the renegotiation phase by receiving the renegotiation packet and simultaneously transmit the power transmitter capability packet 2402 to the wireless power receiver. More specifically, the apparatus for transmitting power wirelessly may need to change a power transmission contract according to the power state of the apparatus for transmitting power wirelessly and thus may proceed with the renegotiation step. In this case, when the wireless power transmitter receives the renegotiation packet, the wireless power transmitter may transmit the power transmitter capability packet 2402 to the wireless power receiver even without receiving the general request packet requesting the power transmitter capability packet 2402.

In detail, FIG. 25 is a flowchart illustrating a wireless charging method when the negotiation step is performed on the wireless charging system and the wireless charging method until the renegotiation step or the renegotiation step is unnecessary.

Referring to FIG. 25, in operation S2501, the wireless power transmitter 2510 may transmit an analog ping to the wireless power receiver 2520.

The wireless power transmitter 2510 may transition from the selection step to the ping step when the object is detected. The wireless power transmitter 2510 activates the wireless power receiver 2520, and may transmit a digital ping for identifying whether the receiver is a wireless power receiver 2520 that is compatible with the WPC standard (S2502). The wireless power receiver 2520 may transmit a signal strength packet in response to the digital ping (S2503).

Upon completion of the ping step, in the identification and configuration step, the wireless power receiver 2520 may transmit an identification packet for notifying the identification information and a configuration packet for notifying the configuration information (S2504 and S2505). The wireless power transmitter 2510 and the wireless power receiver 2520 may transition to the negotiation step if the negotiation field value of the configuration packet is a value indicating to perform the negotiation step.

In the negotiation step, the wireless power receiver 2520 may transmit a FOD status packet for FO detection (S2506). In addition, the wireless power receiver 2520 may transmit a general request packet requesting a power transmitter capability packet for a power transmission contract (S2507). The wireless power transmitter 2520 may transmit the power transmitter capability packet in response to the general request packet (S2508). The wireless power receiver 2520 may transmit a special request packet for proposing a guaranteed power value of the power transmission contract based on the guaranteed power value of the power transmitter capability packet (S2507). For example, the wireless power receiver 2520 may propose a guaranteed power value of the power transfer agreement with a value equal to or less than the guaranteed power value of the power transmitter capability packet. The wireless power transmitter 2510 may transmit an ACK packet in response to the special request packet for proposing a guaranteed power value of the power transmission contract (S2510). In other words, the wireless power transmitter 2510 accepts a guaranteed power value of a power transmission contract proposed by the wireless power receiver. Thereafter, when the power transmission contract is completed, the wireless power receiver 2520 may transmit a special request packet for terminating the negotiation step (S2511). The wireless power transmitter 2510 may transmit an ACK packet in response to the special request packet for terminating the negotiation step (S2512). That is, the wireless power transmitter 2510 may transmit an ACK packet with acceptance of the end of the negotiation step.

In the correcting step, the wireless power receiver 2520 may transmit a received power packet to the wireless power transmitter 2510 in order to predict power loss (S2513). In this case, the received power packet may be an 8-bit received power packet or a 24-bit received power packet. For example, if the received power packet is a 24-bit received power packet, the wireless power transmitter 2510 may transmit an ACK packet in response to the received power packet (not shown).

When the correction step is completed, the power transmission step may proceed. The wireless power receiver 2520 may transmit one or more control error packets to control the transmission power of the wireless power transmitter 2510 (S2514). The wireless power receiver 2520 may transmit the received power packet periodically or arbitrarily (S2516). In this case, the received power packet may be a 24-bit received power packet. The wireless power transmitter 2510 may transmit an ACK packet in response to the received power packet (S2516).

In detail, FIG. 26 is a flowchart illustrating a wireless charging method of performing a renegotiation step on a wireless charging system. In addition, since the wireless charging system according to another embodiment may be the same as the selection step or correction step in the wireless charging method of the wireless charging system of FIG.

Referring to FIG. 26, in the power transmission step, the wireless power receiver 2620 may periodically or arbitrarily transmit a received power packet (S2601). In this case, the received power packet may be a 24-bit received power packet. The wireless power transmitter 2610 may determine that the power transmission contract needs to be changed, and may transmit a NAK packet in response to the reception of the received power packet (S2602). For example, the wireless power transmitter 2610 may have a power state different from that of the negotiation stage. That is, the guaranteed power value that can be sent by the wireless power transmitter 2610 can be changed after the negotiation phase. In this case, the wireless charging system may perform a renegotiation step with NAK packet transmission in response to the reception of the received power packet of the wireless power transmitter 2610. As an example, when the guaranteed power value of the wireless power transmitter 2610 is changed to transmit power to the guaranteed power value of the power transmission contract, the wireless power transmitter 2610 may need to change the power transmission contract. The NAK packet may be transmitted in response to the reception of the received power packet. If the transmittable guaranteed power value of the modified wireless power transmitter is greater than the guaranteed power value of the power transmission contract, the wireless power transmitter 2610 determines that no change in the power transmission contract is necessary and responds to the reception of the received power packet. ACK packet can be transmitted. As another example, the wireless power transmitter 2610 may transmit a NAK packet to reduce a heating amount or an electromagnetic radiation amount. Thereafter, the wireless power receiver 2620 may transmit a general request packet requesting a power transmitter capability packet (S2603). The wireless power transmitter 2620 may transmit a power transmitter capability packet in response to the general request packet (S2604). The wireless power receiver 2620 may transmit a special request packet for proposing a guaranteed power value of the power transmission contract based on the changed guaranteed power value of the power transmitter capability packet (S2605). For example, the wireless power receiver 2620 may propose a guaranteed power value of the power transfer agreement to a value equal to or less than the guaranteed power value of the power transmitter capability packet. The wireless power transmitter 2610 may transmit an ACK packet in response to the special request packet for proposing a guaranteed power value of the power transmission contract (S2606). That is, the wireless power transmitter 2610 is a case where the wireless power receiver 2620 accepts the guaranteed power value of the power transmission contract proposed. Thereafter, when the power transmission contract is completed, the wireless power receiver 2620 may transmit a special request packet for ending the renegotiation step (S2607). The wireless power transmitter 2610 may transmit an ACK packet in response to the special request packet for ending the renegotiation step (S2608). That is, the wireless power transmitter 2610 may send an ACK packet with acceptance of the end of the renegotiation phase.

When the renegotiation step is completed, the wireless power receiver 2620 may resume the power transmission step by transmitting a control error packet (S2609).

Therefore, another embodiment may control the charging power according to the state of the wireless power transmission apparatus. In another embodiment, the wireless power transmission apparatus may control the charging power. In addition, another embodiment may control the charging power to reduce heat generation of the wireless power transmission apparatus. In addition, another embodiment may control the charging power to reduce the electromagnetic emission of the wireless power transmission device. In addition, another embodiment may reduce the number of packets exchanged between the wireless power transmitter and the wireless power receiver to perform the renegotiation step, thereby minimizing the renegotiation step time.

In detail, FIG. 27 is a flowchart illustrating a wireless charging method of performing a renegotiation step on a wireless charging system. In addition, the wireless charging system according to another embodiment may be the same as the selection step, identification and configuration step in the wireless charging method of the wireless charging system of FIG.

Referring to FIG. 27, in the negotiation step, the wireless power receiver 2720 may transmit a FOD status packet for FO detection (S2701). In addition, the wireless power receiver 2720 may transmit a general request packet requesting a power transmitter capability packet for a power transmission contract (S2702). The wireless power transmitter 2720 may transmit the power transmitter capability packet in response to the general request packet (S2703). The wireless power receiver 2720 may transmit a special request packet for proposing a guaranteed power value of the power transmission contract based on the guaranteed power value of the power transmitter capability packet (S2704). For example, the wireless power receiver 2720 may suggest a guaranteed power value of the power transfer agreement with a value greater than the guaranteed power value of the power transmitter capability packet. The wireless power transmitter 2710 may transmit a NAK packet in response to the special request packet for proposing a guaranteed power value of the power transmission contract (S2705). That is, the wireless power transmitter 2710 rejects the guaranteed power value of the power transmission contract proposed by the wireless power receiver 2720. In this case, the guaranteed power value may be determined to be lower than the guaranteed power value of the power transmission contract proposed in S2704. For example, if the wireless power transmitter 2710 transmits a NAK packet in step S2705, the power transmission contract may be set to a default value. As another example, the wireless power receiver 2720 may change the guaranteed power value of the power transfer agreement until the wireless power transmitter 2710 sends an ACK packet and resend the special request packet (not shown). Thereafter, when the power transmission contract is completed, the wireless power receiver 2720 may transmit a special request packet for terminating the negotiation step (S2706). The wireless power transmitter 2710 may transmit an ACK packet in response to the special request packet for terminating the negotiation step (S2707). That is, the wireless power transmitter 2710 may transmit an ACK packet with acceptance of the end of the negotiation step.

In the correcting step, the wireless power receiver 2720 may transmit a received power packet to the wireless power transmitter 2710 to predict power loss (S2708). In this case, the received power packet may be an 8-bit received power packet or a 24-bit received power packet. For example, if the received power packet is a 24-bit received power packet, the wireless power transmitter 2710 may transmit an ACK packet in response to the received power packet (not shown).

When the correction step is completed, the power transmission step may proceed. The wireless power receiver 2720 may transmit one or more control error packets to control the transmission power of the wireless power transmitter 2710 (S2709). The wireless power receiver 2720 may transmit the received power packet periodically or arbitrarily (S2710). In this case, the received power packet may be a 24-bit received power packet. The wireless power transmitter 2710 may determine that the power transmission contract needs to be changed, and may transmit a NAK packet in response to the reception of the received power packet (S2711). For example, the wireless power transmitter 2710 may have a power state different from that of the negotiation stage. That is, the guaranteed power value that can be transmitted by the wireless power transmitter 2710 may be changed after the negotiation step. In this case, the wireless charging system may perform the renegotiation step by transmitting the NAK packet in response to the reception of the received power packet of the wireless power transmitter 2710. For example, if the transmittable guaranteed power value of the wireless power transmitter 2710 is changed to transmit power at a value greater than the guaranteed power value of the power transmission contract, the wireless power transmitter 2710 may transmit a power transmission contract. The NAK packet may be transmitted in response to the reception of the received power packet by determining that a change is required. As another example, the wireless power transmitter 2710 may transmit a NAK packet to reduce a heating amount or an electromagnetic radiation amount. Thereafter, the wireless power receiver 2720 may transmit a general request packet requesting a power transmitter capability packet (S2712). The wireless power transmitter 2720 may transmit the power transmitter capability packet in response to the general request packet (S2713). The wireless power receiver 2720 may send a special request packet for proposing a guaranteed power value of the power transmission contract based on the changed guaranteed power value of the power transmitter capability packet (S2714). For example, the wireless power receiver 2720 may propose a guaranteed power value of the power transfer agreement with a value equal to or less than the guaranteed power value of the power transmitter capability packet. The wireless power transmitter 2710 may transmit an ACK packet in response to the special request packet for proposing a guaranteed power value of the power transmission contract (S2715). That is, the wireless power transmitter 2710 accepts the guaranteed power value of the power transmission contract proposed by the wireless power receiver 2720. Thereafter, when the power transmission contract is completed, the wireless power receiver 2720 may transmit a special request packet for terminating the renegotiation step (S2716). The wireless power transmitter 2710 may transmit an ACK packet in response to the special request packet for terminating the renegotiation step (S2717). That is, the wireless power transmitter 2710 may send an ACK packet with acceptance of the end of the renegotiation phase.

When the renegotiation step is completed, the wireless power receiver 2720 may proceed with the power transmission step again by transmitting a control error packet (S2718).

Therefore, another embodiment may control the charging power according to the state of the wireless power transmission apparatus. In another embodiment, the wireless power transmission apparatus may control the charging power. In addition, another embodiment may control the charging power to reduce heat generation of the wireless power transmission apparatus. In addition, another embodiment may control the charging power to reduce the electromagnetic emission of the wireless power transmission device. In addition, another embodiment may minimize the charging time by increasing the strength of the charging power. In addition, another embodiment may reduce the number of packets exchanged between the wireless power transmitter and the wireless power receiver to perform the renegotiation step, thereby minimizing the renegotiation step time.

In detail, the wireless charging method in the wireless power transmitter according to an embodiment may be a wireless charging method for the wireless power transmitter on the wireless charging system of FIGS. 25, 26, and 27.

Referring to FIG. 28, in the power transmission step, the wireless power transmitter may transmit power with a guaranteed power value according to a power transmission contract in operation S2801.

The wireless power transmitter may collect transmitter state information (S2802). For example, the transmitter state information may include a guaranteed power value that the wireless power transmitter can transmit, a potential power value that the wireless power transmitter is designed to transmit, and the like. In addition, the transmitter status information may be information recorded in a power transmitter capability packet.

The wireless power transmitter may determine whether a transition is necessary in the renegotiation step based on the collected transmitter state information (S2803 and S2804). More specifically, the case where the renegotiation step is required is when the wireless power transmitter wants to change the power transmission contract. For example, the wireless power transmitter may attempt to perform a renegotiation step for changing a power state that can be transmitted, reducing heat generation, and reducing electromagnetic waves.

If it is determined that the renegotiation step is necessary, the wireless power transmitter may transmit the NAK packet in response to the received power packet and then transition to the renegotiation step (S2805). The received power packet may be a 24-bit receive power packet.

The wireless power transmitter may transmit the power transmitter capability packet after receiving the general request packet for the power transmitter capability packet request (S2806). More specifically, the wireless power transmitter may transmit the power transmitter capability packet in response to receiving the general request packet (the power transmitter capability packet request, ie, the request field is set to 0x31).

The wireless power transmitter may transmit an ACK packet after receiving the special request packet proposing a guaranteed power value of the power transmission contract (S2807). For example, the wireless power transmitter may transmit a guaranteed power value (guaranteed power value of a special request packet) required by the wireless power receiver before accepting the power transmission contract.

The wireless power transmitter may transmit an ACK packet after receiving the special request packet for terminating the renegotiation step (S2808).

The wireless power transmitter may transition to the power transmission step of S2801 after modifying the guaranteed power value of the power transmission contract (S2809).

If the renegotiation step is not necessary in step S2804, the wireless power transmitter may transmit an ACK packet in response to the received power packet and then transition to the power transmission step of S2801 (S2810).

Therefore, one embodiment may control the charging power according to the state of the wireless power transmission apparatus. In addition, in one embodiment, the wireless power transmitter may control the charging power. In addition, one embodiment may control the charging power to reduce heat generation of the wireless power transmission apparatus. In addition, one embodiment may control the charging power to reduce the electromagnetic emission of the wireless power transmission apparatus. In addition, an embodiment may minimize the charging time by increasing the strength of the charging power. In addition, one embodiment may reduce the number of packets exchanged between the wireless power transmitter and the wireless power receiver to perform the renegotiation step, thereby minimizing the renegotiation step time.

In detail, the wireless charging method in the wireless power receiver according to an embodiment may be a wireless charging method for the wireless power receiver on the wireless charging system of FIGS. 25, 26, and 27.

Referring to FIG. 29, in step S2901, the wireless power receiver may transmit a received power packet. The received power packet may be a 24-bit receive power packet.

After receiving the NAK packet, the wireless power receiver may transmit a general request packet to transition to the renegotiation step (S2902). More specifically, when the wireless power receiver receives the NAK packet in response to the transmission of the received power packet, the wireless power receiver may transmit a general request packet (a power transmitter capability packet request, that is, the request field is set to 0x31).

The wireless power receiver may receive a power transmitter capability packet (S2903).

The wireless power receiver may determine whether to transition from the renegotiation step to the power transmission step (S2904). More specifically, there may be a case where the transition from the renegotiation step to the power transfer step occurs. For example, the wireless power transmitter may transmit a guaranteed power value (a guaranteed power value of a special request packet) required by the wireless power receiver before accepting the power transmission contract. There may be a case where the transition from the renegotiation phase to the power transfer phase does not occur. For example, the charging of the wireless power receiver is completed. In addition, it may be necessary to receive a certain level of power due to system stability of the electronic device connected to the wireless power receiver. In this case, the guaranteed power value required by the wireless power receiver (guaranteed power value of the special request packet) is larger than the guaranteed power value (guaranteed power value of the power transmitter capability packet) that the wireless power transmitter can send.

If it is determined that the transition to the power transmission step, the wireless power receiver may transmit a special request packet for proposing a guaranteed power value of the power transmission contract (S2905). The guaranteed power value of the special request packet may be less than the guaranteed power value of the power transmitter capability packet.

The wireless power receiver may receive an ACK packet in response to a special request packet for proposing a guaranteed power value of the power transmission contract to complete the power transmission contract (S2906).

The wireless power receiver may transmit a special request packet for ending the renegotiation step (S2907).

When the wireless power receiver receives the ACK packet in response to the special request packet for terminating the renegotiation step, the wireless power receiver may transition to the power transmission step and transmit a control error packet (S2908).

If it is determined in step S2903 not to transition to the power transmission step, the wireless power receiver may terminate power reception (S2909).

In detail, FIG. 30 is a flowchart illustrating a wireless charging method of performing a renegotiation step on a wireless charging system. In addition, since the wireless charging system according to another embodiment may be the same as the selection step or correction step in the wireless charging method of the wireless charging system of FIG.

Referring to FIG. 30, in the power transmission step, the wireless power receiver 3020 may periodically or arbitrarily transmit a received power packet (S3001). In this case, the received power packet may be a 24-bit received power packet. The wireless power transmitter 3010 determines that the power transmission contract needs to be changed, and may transmit a NAK packet in response to the reception of the received power packet (S3002). More specifically, the wireless power transmitter 3010 may have a power state different from that of the negotiation stage. That is, the guaranteed power value that can be sent by the wireless power transmitter 3010 may be changed after the negotiation step. In this case, the wireless charging system may perform the renegotiation step by transmitting the NAK packet in response to the reception of the received power packet of the wireless power transmitter 3010. For example, if the transmittable guaranteed power value of the wireless power transmitter 3010 is changed and fails to send power to the guaranteed power value of the power transmission contract, the wireless power transmitter 3010 needs to change the power transmission contract. The NAK packet may be transmitted in response to the reception of the received power packet. If the transmittable guaranteed power value of the modified wireless power transmitter is greater than the guaranteed power value of the power transmission contract, the wireless power transmitter 3010 determines that no change in the power transmission contract is necessary and responds to the reception of the received power packet. ACK packet can be transmitted. As another example, the wireless power transmitter 3010 may transmit a NAK packet to reduce the heating value or the electromagnetic radiation amount. Thereafter, the wireless power receiver 3020 may transmit a renegotiation packet (S3003). The wireless power transmitter 3020 may transmit a power transmitter capability packet in response to the renegotiation packet (S3004). The wireless power receiver 3020 may transmit a special request packet for proposing a guaranteed power value of the power transmission contract based on the changed guaranteed power value of the power transmitter capability packet (S3005). For example, the wireless power receiver 3020 may propose a guaranteed power value of the power transfer agreement to a value equal to or less than the guaranteed power value of the power transmitter capability packet. The wireless power transmitter 3010 may transmit an ACK packet in response to the special request packet for proposing a guaranteed power value of the power transmission contract (S3006). That is, the wireless power transmitter 3010 accepts a guaranteed power value of the power transmission contract proposed by the wireless power receiver 3020. Thereafter, when the power transmission contract is completed, the wireless power receiver 3020 may transmit a special request packet for terminating the renegotiation step (S3007). The wireless power transmitter 3010 may transmit an ACK packet in response to the special request packet for terminating the renegotiation step (S3008). That is, the wireless power transmitter 3010 may transmit an ACK packet with acceptance of the end of the renegotiation step.

When the renegotiation step is completed, the wireless power receiver 3020 may resume the power transmission step by transmitting a control error packet (S3009).

Therefore, another embodiment may control the charging power according to the state of the wireless power transmission apparatus. In another embodiment, the wireless power transmission apparatus may control the charging power. In addition, another embodiment may control the charging power to reduce heat generation of the wireless power transmission apparatus. In addition, another embodiment may control the charging power to reduce the electromagnetic emission of the wireless power transmission device. Further, another embodiment may reduce the number of packets exchanged between the wireless power transmitter and the wireless power receiver to perform the renegotiation step, thereby minimizing the renegotiation step time.

In detail, FIG. 31 is a flowchart illustrating a wireless charging method of performing a renegotiation step on a wireless charging system. In addition, the wireless charging system according to another embodiment may be the same as the selection step, identification and configuration step in the wireless charging method of the wireless charging system of FIG.

Referring to FIG. 31, in the negotiation step, the wireless power receiver 3120 may transmit a FOD status packet for FO detection (S3101). In addition, the wireless power receiver 3120 may transmit a general request packet requesting a power transmitter capability packet for a power transmission contract (S3102). The wireless power transmitter 3120 may transmit a power transmitter capability packet in response to the general request packet (S3103). The wireless power receiver 3120 may transmit a special request packet for proposing a guaranteed power value of the power transmission contract based on the guaranteed power value of the power transmitter capability packet (S3104). For example, the wireless power receiver 3120 may suggest a guaranteed power value of the power transfer agreement with a value greater than the guaranteed power value of the power transmitter capability packet. The wireless power transmitter 3110 may transmit a NAK packet in response to a special request packet for proposing a guaranteed power value of the power transmission contract (S3105). That is, the wireless power transmitter 3110 rejects the guaranteed power value of the power transmission contract proposed by the wireless power receiver 3120. In this case, the guaranteed power value may be determined to be lower than the guaranteed power value of the power transmission contract proposed in S3104. For example, if the wireless power transmitter 3110 transmits a NAK packet in step S3105, the power transmission contract may be set to a default value. As another example, the wireless power receiver 3120 may change the guaranteed power value of the power transmission contract until the wireless power transmitter 3110 sends an ACK packet and transmit the special request packet again (not shown). Thereafter, when the power transmission contract is completed, the wireless power receiver 3120 may transmit a special request packet for terminating the negotiation step (S3106). The wireless power transmitter 3110 may transmit an ACK packet in response to the special request packet for terminating the negotiation step (S3107). That is, the wireless power transmitter 3110 may transmit an ACK packet with acceptance of the end of the negotiation step.

In the correcting step, the wireless power receiver 3120 may transmit a received power packet to the wireless power transmitter 3110 to predict power loss (S3108). In this case, the received power packet may be an 8-bit received power packet or a 24-bit received power packet. For example, if the received power packet is a 24-bit received power packet, the wireless power transmitter 3110 may transmit an ACK packet in response to the received power packet (not shown).

When the correction step is completed, the power transmission step may proceed. The wireless power receiver 3120 may transmit one or more control error packets to control the transmission power of the wireless power transmitter 3110 (S3109). The wireless power receiver 3120 may periodically or arbitrarily transmit a received power packet (S3110). In this case, the received power packet may be a 24-bit received power packet. The wireless power transmitter 3110 may determine that the power transmission contract needs to be changed and may transmit a NAK packet in response to the reception of the received power packet (S3111). For example, the wireless power transmitter 3110 may have a power state different from that of the negotiation stage. That is, the guaranteed power value that can be transmitted by the wireless power transmitter 3110 may be changed after the negotiation step. In this case, the wireless charging system may perform the renegotiation step by transmitting the NAK packet in response to the reception of the received power packet of the wireless power transmitter 3110. More specifically, when the transmittable guaranteed power value of the wireless power transmitter 3110 is changed to transmit power with a value greater than the guaranteed power value of the power transmission contract, the wireless power transmitter 3110 may transmit a power transmission contract. The NAK packet may be transmitted in response to the reception of the received power packet by determining that a change is required. As another example, the wireless power transmitter 3110 may transmit a NAK packet to reduce a heating amount or an electromagnetic radiation amount. Thereafter, the wireless power receiver 3120 may transmit a renegotiation packet (S3112). The wireless power transmitter 3120 may transmit a power transmitter capability packet in response to the renegotiation packet (S3113). The wireless power receiver 3120 may transmit a special request packet for proposing a guaranteed power value of the power transmission contract based on the changed guaranteed power value of the power transmitter capability packet (S3114). For example, the wireless power receiver 3120 may suggest a guaranteed power value of the power transfer agreement with a value equal to or less than the guaranteed power value of the power transmitter capability packet. The wireless power transmitter 3110 may transmit an ACK packet in response to the special request packet for proposing a guaranteed power value of the power transmission contract (S3115). That is, the wireless power transmitter 3110 accepts the guaranteed power value of the power transmission contract proposed by the wireless power receiver 3120. Thereafter, when the power transmission contract is completed, the wireless power receiver 3120 may transmit a special request packet for terminating the renegotiation step (S3116). The wireless power transmitter 3110 may transmit an ACK packet in response to the special request packet for terminating the renegotiation step (S3117). That is, the wireless power transmitter 3110 may transmit an ACK packet with acceptance of the end of the renegotiation step.

When the renegotiation step is completed, the wireless power receiver 3120 may resume the power transmission step by transmitting a control error packet (S3118).

Therefore, another embodiment may control the charging power according to the state of the wireless power transmission apparatus. In another embodiment, the wireless power transmission apparatus may control the charging power. In addition, another embodiment may control the charging power to reduce heat generation of the wireless power transmission apparatus. In addition, another embodiment may control the charging power to reduce the electromagnetic emission of the wireless power transmission device. In addition, another embodiment may minimize the charging time by increasing the strength of the charging power. Further, another embodiment may reduce the number of packets exchanged between the wireless power transmitter and the wireless power receiver to perform the renegotiation step, thereby minimizing the renegotiation step time.

In detail, the wireless charging method in the wireless power transmitter according to another embodiment may be a wireless charging method for the wireless power transmitter on the wireless charging system of FIGS. 25, 30, and 31.

Referring to FIG. 32, in the power transmission step, the wireless power transmitter may transmit power with a guaranteed power value according to a power transmission contract in operation S3201.

The wireless power transmitter may collect transmitter state information (S3202). For example, the transmitter state information may include a guaranteed power value that the wireless power transmitter can transmit, a potential power value that the wireless power transmitter is designed to transmit, and the like. In addition, the transmitter status information may be information recorded in a power transmitter capability packet.

The wireless power transmitter may determine whether a transition is necessary in the renegotiation step based on the collected transmitter state information (S3203 and S3204). More specifically, the case where the renegotiation step is required is when the wireless power transmitter wants to change the power transmission contract. For example, the wireless power transmitter may attempt to perform a renegotiation step for changing a power state that can be transmitted, reducing heat generation, and reducing electromagnetic waves.

If it is determined that the renegotiation step is required, the wireless power transmitter may transmit the NAK packet in response to the received power packet and then transition to the renegotiation step (S3205). The received power packet may be a 24-bit receive power packet.

The wireless power transmitter may transmit a power transmitter capability packet after receiving the renegotiation packet (S3206). More specifically, the wireless power transmitter may transmit the power transmitter capability packet in response to receiving the renegotiation packet.

The wireless power transmitter may transmit an ACK packet after receiving a special request packet suggesting a guaranteed power value of the power transmission contract (S3207). For example, the wireless power transmitter may transmit a guaranteed power value (guaranteed power value of a special request packet) required by the wireless power receiver before accepting the power transmission contract.

The wireless power transmitter may transmit an ACK packet after receiving the special request packet for ending the renegotiation step (S3208).

The wireless power transmitter may transition to the power transmission step of S2801 after modifying the guaranteed power value of the power transmission contract (S3209).

If the renegotiation step is not necessary in step S3204, the wireless power transmitter may transition to the power transmission step of S2801 by transmitting an ACK packet in response after receiving the received power packet (S3210).

In detail, the wireless charging method in the wireless power receiver according to another embodiment may be a wireless charging method for the wireless power receiver on the wireless charging system of FIGS. 25, 30, and 31.

Referring to FIG. 33, in a power transmission step, the wireless power receiver may transmit a received power packet (S3301). The received power packet may be a 24-bit receive power packet.

After receiving the NAK packet, the wireless power receiver may transmit a renegotiation packet to transition to a renegotiation step (S3302). More specifically, the wireless power receiver may transmit the renegotiation packet when receiving the NAK packet in response to the transmission of the received power packet.

The wireless power receiver may receive a power transmitter capability packet (S3303).

The wireless power receiver may determine whether to transition from the renegotiation step to the power transmission step (S3304). More specifically, there may be a case where the transition from the renegotiation step to the power transfer step occurs. For example, the wireless power transmitter may transmit a guaranteed power value (a guaranteed power value of a special request packet) required by the wireless power receiver before accepting the power transmission contract. There may be a case where the transition from the renegotiation phase to the power transfer phase does not occur. For example, the charging of the wireless power receiver is completed. In addition, it may be necessary to receive a certain level of power due to system stability of the electronic device connected to the wireless power receiver. In this case, the guaranteed power value required by the wireless power receiver (guaranteed power value of the special request packet) is larger than the guaranteed power value (guaranteed power value of the power transmitter capability packet) that the wireless power transmitter can send.

If it is determined that the transition to the power transmission step, the wireless power receiver may transmit a special request packet for proposing a guaranteed power value of the power transmission contract (S3305). The guaranteed power value of the special request packet may be less than the guaranteed power value of the power transmitter capability packet.

The wireless power receiver may receive an ACK packet in response to a special request packet for proposing a guaranteed power value of the power transmission contract to complete the power transmission contract (S3306).

The wireless power receiver may transmit a special request packet for ending the renegotiation step (S3307).

When the wireless power receiver receives the ACK packet in response to the special request packet for terminating the renegotiation step, the wireless power receiver may transition to the power transmission step and transmit a control error packet (S3308).

If it is determined in step S3303 not to transition to the power transmission step, the wireless power receiver may end the power reception (S3309).

Referring to FIG. 34, the first time T1 may be a time at which the wireless power transmitter receives a received power packet and delivers a NAK packet to the wireless power receiver. For example, the first time T1 may be about 250 ms. The second time T2 may be the time it takes for the wireless power receiver to transmit the generic request packet. For example, the second time T2 may be 22 ms. The third time T3 may be a time at which the wireless power transmitter receives the general request packet and forwards the power transmitter capability packet to the wireless power receiver. For example, the third time T3 may be about 250 ms. The fourth time T4 may be a time taken for the wireless power receiver to transmit the first or second special request packet. For example, the first special request packet may be a special request packet that proposes a guaranteed power value of a power transmission contract. The second special request packet may be a special request packet for ending the renegotiation step. The fourth time T4 may be about 27.5 ms. The fifth time T5 may be a time at which the wireless power transmitter receives the first special request packet and forwards the ACK packet to the wireless power receiver. For example, the fifth time T5 may be about 250 ms. The sixth time T6 may be a time taken for the wireless power transmitter to receive the second special request packet and transmit the ACK packet. For example, the sixth time T6 may be 10 ms.

That is, the renegotiation step time according to an embodiment may be at least T1 + T2 + T3 + T4 + T5 + T4 + T6 = T renegotiation. For example, the T renegotiation may be 877 ms.

Therefore, it is possible to minimize the renegotiation step time of the wireless charging method according to an embodiment.

Referring to FIG. 35, three transmitting coils may be disposed. In order to perform uniform power transfer in a charging region of a constant size, at least one of the plurality of transmitting coils may be overlapped. In FIG. 40, the first coil 4010 and the second coil 4020 are disposed side by side on the shielding material 4040 at the first layer, and the third coil 4030 is disposed on the first coil and the second coil. It may be disposed overlapping the second layer.

The first coil 4010, the second coil 4020, and the third coil 4030 may be manufactured according to the specifications of the coils defined in the WPC or PMA, and the same within the extent to which the respective physical characteristics are acceptable. can do.

For example, the transmitting coil may have a specification as shown in Table 1 below.

ParameterParameter	SymbolSymbol	ValueValue
외측 길이(Outer length)Outer length	doldol	53.2±0.5 mm53.2 ± 0.5 mm
내측 길이( Inner length)Inner length	dildil	27.5±0.5 mm27.5 ± 0.5 mm
외측 너비(Outer width)Outer width	dowdow	45.2±0.5 mm45.2 ± 0.5 mm
내측 너비(Inner width)Inner width	diwdiw	19.5±0.5 mm19.5 ± 0.5 mm
두께(Thickness)Thickness	dcdc	1.5±0.5 mm1.5 ± 0.5 mm
권선수(Number of turns per layer)Number of turns per layer	NN	12 turns12 turns
층수(Number of layers)Number of layers		1One

Table 1 is a specification for the A13 type transmission coil defined in the WPC, and in one embodiment, the first coil 4010, the second coil 4020, and the third coil 4030 have an outer length defined in Table 1, It can be made with inner length, outer width, inner width, thickness and number of turns. Of course, the first coil 4010, the second coil 4020, and the third coil 4030 may have the same physical characteristics within an error range by the same manufacturing process.

However, as shown in FIG. 21, each of the first coil 4010, the second coil 4020, and the third coil 4030 may have a different inductance value according to a position disposed in a relationship with the shielding material.

For example, the first coil 4010 and the second coil 4020 satisfy the specifications of Table 1 and have an inductance of 12.5 uH, and the third coil 4030 has a first coil having a separation distance from the shielding material. Unlike the 4010 and the second coil 4020, it may have an inductance smaller than 12.5 uH.

For example, the first coil 4010 and the second coil 4020 are disposed in contact with the shielding material, but the third coil 4030 may be spaced apart from the shielding material by a predetermined height.

In one embodiment, an adhesive may be disposed between the first coil 4010, the second coil 4020, or the third coil 4030 and the shielding material.

Therefore, in one embodiment, the third coil 4030 has a number of turns more than the number of turns of the first coil 4010 and the second coil 4020 to have the same inductance as the first coil 4010 and the second coil 4020. (E.g., 0.5 or 1 or 2 times) can be made to have more turns.

In one embodiment, the third coil 4030 may have a number of turns of 12.5 or 13 or 14 times.

In other words, the centrally located third coil 4030 is located farther from the shielding material than the first coil 4010 and the second coil 4020 so that the measured inductance is measured in the first coil 4010 and the second coil 4020. ), The length of the conducting wire constituting the third coil 4030 may be slightly longer than that of the first coil 4010 and the second coil 4020 to equally adjust the inductance.

In an exemplary embodiment, the length of the conductive wire constituting the third coil 4030 is slightly longer than that of the first coil 4010 and the second coil 4020, so that the third coil 4030 may be the first coil 4030. And despite being located farther from the shield than the second coil 4020, the inductance of the three coils may be equal to 12.5 uH. In one embodiment, the same inductance of the coil means that it has an error range within ± 0.5 uH.

The overlapping transmission coils may have a smaller inductance measured as the distance from the shield is farther away, and the length of the transmission coil may be longer to increase the inductance as the distance from the shield is farther away.

Referring to FIG. 36, when each of the three coils included in the wireless power transmitter has different inductances, three coils including a capacitor for generating the same resonant frequency as the three drive circuits 4110 connected to each coil are included. LC resonant circuit 4120 is required.

Even if the wireless power transmitter includes a plurality of coils, the resonant frequency generated by the wireless power transmitter to perform power transmission cannot be different for each of the transmitting coils, and should be in accordance with the standard resonant frequency supported by the wireless power transmitter.

The resonant frequency generated by the LC resonant circuit 4120 may vary according to the inductance of the coil and the capacitance of the capacitor.

For example, if the resonant frequency (fr, resonant frequency) may be 100Khz, and the capacitance of the capacitor connected to the coil to generate the resonance frequency is 200nF, to use only one capacitor, all three coils are 12.5. uH must be satisfied. If the inductances of the three coils are different from each other, three capacitors having different capacitances are required to generate a resonance frequency of 100 kHz. In addition, three drive circuits 4110 including an inverter for applying an alternating voltage in each LC resonant circuit 4120 are also required.

Referring to FIG. 37, when the inductances of the three coils of the wireless power transmitter are the same, the wireless power transmitter may include only one drive circuit 4210, and the wireless power receiver among one drive circuit 4210 and three coils. The switch 4230 may be controlled to connect the coil of the wireless power transmitter with the coil having the highest power transmission efficiency.

Compared with FIG. 36, the wireless power transmitter can reduce the area occupied by the component by using only one drive circuit 4210, thereby miniaturizing the wireless power transmitter itself, and reducing raw material costs required for manufacturing. .

In one embodiment, the wireless power transmitter may use the signal strength indicator in the ping step to calculate the power transfer efficiency between the three coils of the wireless power transmitter and the coil of the wireless power receiver.

Alternatively, in another embodiment, the wireless power transmitter may select a coil of the wireless power transmitter having a high coupling coefficient by calculating a coupling coefficient between the transmission and reception coils.

Alternatively, in another embodiment, the wireless power transmitter may control the switch 4230 to calculate a factor (Q factor) to identify a coil of the wireless power transmitter having a high factor and to connect with the drive circuit 4210.

Referring to FIG. 38, a power transmitter includes a drive circuit 4310 for converting an input voltage, a switch 4320 for connecting the drive circuit 4310 and an LC resonant circuit, a plurality of transmission coils 4330, and a plurality of wireless power transmitters. One capacitor 4340 connected in series with the coil of the control unit 4320 may include a control unit 4350 to control the opening and closing.

The controller 4350 identifies a coil of the wireless power receiver and a coil of the wireless power transmitter having the highest power transmission efficiency among the plurality of coils 4330 of the wireless power transmitter, and drives the coil of the identified wireless power transmitter in the drive circuit 4310. Control to close the switch to connect the

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, 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.

Claims

A power transmitter including one or more transmitting coils;

A power converter converting the intensity of DC power applied from the outside;

A communication unit exchanging information with an external device; And

A control unit for changing a power transmission contract by transmitting a predetermined packet through the communication unit;

The controller collects wireless power transmitter state information and transitions to a renegotiation step based on the wireless power transmitter state information.
According to claim 1,

The transmitter state information includes a guaranteed power value that the wireless power transmitter can transmit.
According to claim 1,

The control unit transmits a NAK packet after receiving a received power packet to transition to a renegotiation step.
The method of claim 3, wherein

The control unit transmits a power transmitter capability packet after receiving a general request packet.
The method of claim 3, wherein

The control unit transmits a power transmitter capability packet after receiving a renegotiation packet.
According to claim 1,

Including a sensing unit for measuring the internal temperature, the electromagnetic wave intensity emitted from the power transmitter or the intensity of the external electromagnetic wave

The control unit performs a renegotiation step to change the power transmission contract based on the measured internal temperature value, electromagnetic wave intensity value or external electromagnetic wave intensity value of the sensing unit.
Receiving coil;

A communication unit exchanging information with an external device through the receiving coil; And

And a controller for transitioning to a renegotiation step according to the control of the external device.
The method of claim 7, wherein

And the control unit transitions to a renegotiation step when receiving a NAK packet from the external device after transmitting a received power packet to the external device.
The method of claim 8,

The control unit is a wireless power receiver for transmitting a general request packet after receiving the NAK packet.
The method of claim 8,

The control unit is a wireless power receiver for transmitting a renegotiation packet after receiving the NAK packet.
A wireless charging method in a wireless power transmitter for wirelessly transmitting power to a wireless power receiver,

In a power transmission step, the wireless power transmitter transmitting power at a guaranteed power value in accordance with a power transmission contract;

The wireless power transmitter collecting transmitter status information;

Determining, by the wireless power transmitter, whether a transition is necessary to a renegotiation step based on the collected transmitter state information; And

And transmitting, by the wireless power transmitter, a NAK packet after receiving a received power packet to transition to a renegotiation step if a renegotiation step is required.
The method of claim 11, wherein

And after the transition to the renegotiation step, the wireless power transmitter transmitting a power transmitter capability packet upon receiving a general request packet.
The method of claim 11, wherein

And after the transition to the renegotiation step, the wireless power transmitter transmits a power transmitter capability packet upon receiving a renegotiation packet.
The method of claim 11, wherein

And the transmitter state information includes a guaranteed power value that the wireless power transmitter can send.
A wireless charging method in a wireless power receiver that wirelessly receives power from a wireless power transmitter,

In the power transmission step, the wireless power receiver transmits a received power packet;

And the wireless power receiver transitions to a renegotiation step after receiving a NAK packet.
The method of claim 15,

And the wireless power receiver transitions to the renegotiation step after receiving the NAK packet.
The method of claim 16,

The generic request packet is a packet for requesting a power transmitter capability packet from the wireless power transmitter.
The method of claim 15,

And the wireless power receiver transitioning to the renegotiation step after receiving the NAK packet comprises: transitioning to the renegotiation step by transmitting the renegotiation packet after the wireless power receiver receives the NAK packet.
The method of claim 18,

After transitioning to a renegotiation step, the wireless power receiver further comprising receiving a power transmitter capability packet from the wireless power transmitter.
The method of claim 15,

And in the renegotiation step, determining whether the wireless power receiver has transitioned to a power transmission step.