WO2018199671A1 - Wireless charging method, and device and system therefor - Google Patents

Abstract

The present invention relates to a wireless power transmission technology and, more particularly, to a wireless charging method, and a device and a system therefor. A wireless charging method according to an embodiment relates to a wireless charging method in a wireless power transmitter for wirelessly transmitting power to a wireless power receiver, and the method may comprise: a step of performing charging in a second charging mode; a step of determining whether the charging performed in the second charging mode is in a charging mode restricted state; a first charging mode change step of, when the charging is in the charging mode restricted state, changing the second charging mode into a first charging mode; and a step of performing charging in the first charging mode.

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 this 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 for wireless charging is increased, the wireless power receiver generates heat and emits electromagnetic waves due to a high intensity input signal. If the temperature increases due to heat generation, the wireless power receiver may cause problems such as deterioration of wireless power reception performance or damage to an internal system. In addition, when the load is a battery, the wireless power receiver may have a problem that the load is damaged when a high intensity input signal is received even though the state of charge is close to a buffer.

In addition, the wireless power transmitter needs to increase the charging speed while solving the above problems.

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.

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

In addition, another object of the present invention is to improve the heat generation phenomenon of the wireless power receiver.

In addition, another object of the present invention is to prevent damage to the load by the received power.

In addition, another object of the present invention is to increase the wireless charging speed.

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 charging method according to the embodiment, the wireless charging method in a wireless power transmitter for transmitting power wirelessly to the wireless power receiver, performing the charging in the second charging mode; Determining whether the charging mode is restricted while performing charging in the second charging mode; A first charging mode changing step of changing from a second charging mode to a first charging mode when the charging mode is restricted; And performing charging in the first charging mode.

In addition, in the wireless charging method according to the embodiment, the charging mode restriction state may be a state in which the wireless power receiver reduces the strength of the charging power supplied by the wireless power transmitter due to an event of the wireless power receiver.

In addition, in the wireless charging method according to the embodiment, the first charging mode is a low power charging mode, the second charging mode is a high power charging mode, and the wireless power transmitter is in the first charging mode than the second charging mode when the charging mode is restricted. Higher charging power may be provided to the wireless power receiver.

In addition, the wireless charging method according to the embodiment comprises the steps of determining whether the charge mode limitation release state while performing charging in the first charging mode; And a charging mode second changing step of changing from the first charging mode to the second charging mode when the charging mode restriction release state is established.

In addition, in the wireless charging method according to the embodiment, the charge mode restriction release state may be a state in which the wireless power receiver stops controlling the charging power supplied by the wireless power transmitter due to an event.

In addition, in the wireless charging method according to the embodiment, the first charging mode is a low power charging mode, the second charging mode is a high power charging mode, and the wireless power transmitter is a second charging mode than the first charging mode when the charging mode restriction release state. May provide higher charging power to the wireless power receiver.

The wireless charging method according to the embodiment may include determining whether the charging mode is restricted while performing charging in the second charging mode, by sensing a driving current; Determining whether the sensed driving current value is in a first state equal to or less than a first threshold current value; And determining whether the first state is maintained for a first time.

In addition, the wireless charging method according to the embodiment of the first charging mode change step, power transmission stop step; Reconnecting with the wireless power receiver; Receiving a packet for initial power control after transitioning to a power transfer step; Transmitting a first packet to announce second charging mode support; Receiving a first response packet requesting a second charging mode; And ignoring the first response packet.

The wireless charging method according to the embodiment may further include determining whether a reconnection time after receiving the first response packet is within a critical reconnection time after receiving the first response packet, and if the reconnection time is within the threshold reconnection time. The charging may be performed in the first charging mode by ignoring the first response packet.

The wireless charging method according to the embodiment may initialize the charging mode restriction state information and perform charging in the second charging mode when the reconnection time exceeds the threshold reconnection time.

Also, the wireless charging method according to the embodiment may include determining whether the charge mode restriction release state comprises: sensing a driving current; Determining whether the sensed drive current value is in a second state equal to or greater than a second threshold current value; And determining whether the second state is maintained for a second time.

Also, the wireless charging method according to the embodiment may include determining whether the charging mode is restricted while performing charging in the second charging mode, by sensing an operating frequency; Determining whether the sensed operating frequency value is in a third state equal to or greater than a first threshold frequency value; And determining whether the third state is maintained for a third time.

Also, the wireless charging method according to the embodiment may include determining whether the charge mode restriction release state comprises: sensing an operating frequency; Determining whether the sensed operating frequency value is a fourth state less than or equal to a second threshold frequency value; And determining whether the fourth state is maintained for a fourth time.

Also, the wireless charging method according to the embodiment may include determining whether the charging mode is restricted while performing charging in the second charging mode, by sensing an operating frequency; Determining whether the sensed operating frequency value is greater than or equal to a third threshold frequency value; Sensing an operating duty ratio if the sensed operating frequency value is greater than or equal to a third threshold frequency value; Determining a fifth state in which the operation duty ratio is less than or equal to a first threshold duty ratio; And determining whether the fifth state is maintained for a fifth time.

Also, the wireless charging method according to the embodiment may include determining whether the charge mode restriction release state comprises: sensing an operation duty ratio if the charge state is not the fourth state; Determining whether the sensed operation duty ratio is a seventh state equal to or greater than a second threshold duty ratio; And determining whether the seventh state is maintained for a seventh time.

In addition, the wireless charging method according to the embodiment of the first charging mode change step, power transmission stop step; Reconnecting with the wireless power receiver; Receiving a packet for initial power control after transitioning to a power transfer step; And not transmitting the first packet indicating the second charging mode support.

The wireless charging method according to the embodiment may further include determining whether the recharging time is within a critical reconnection time after receiving the packet for the initial power control, and wherein the reconnection time is the critical reconnection time. If it is within the time, charging may be performed in the first charging mode without transmitting the first packet.

The wireless charging method according to the embodiment of the present invention may further include: recharging the charging mode restriction state information when the reconnection time exceeds the threshold reconnection time; A first packet transmission step of informing a second charging mode support when the charging mode restriction state information is initialized; And receiving a first response packet requesting a second charging mode when the first packet is transmitted. When receiving the first response packet, charging may be performed in the second charging mode.

In addition, the wireless charging method according to an embodiment of the present invention, the second change of the charging mode, the first packet transmission step of informing the second charging mode support; Receiving a first response packet requesting a second charging mode when transmitting the first packet; And performing charging in the second charging mode when receiving the first response packet.

A wireless charging method in accordance with an embodiment of the present invention provides a wireless charging method in a wireless power transmitter for wirelessly transmitting power to a wireless power receiver, comprising: performing charging with a first guaranteed power; Determining whether a guaranteed power limit state is being performed while charging with the first guaranteed power; Changing a first power transmission contract from a first guaranteed power to a second guaranteed power when the guaranteed power is limited; And performing charging at a second guaranteed power.

Also, in the wireless charging method according to the embodiment, the guaranteed power limit state may be a state in which the wireless power receiver reduces the strength of the charging power supplied by the wireless power transmitter due to an event of the wireless power receiver.

In addition, the wireless charging method according to the embodiment includes the step of determining whether the guaranteed power limit is released while performing the charging with the second guaranteed power; And changing a second power transmission contract from the second guaranteed power to the first guaranteed power when the guaranteed power limit is released.

In addition, in the wireless charging method according to the embodiment, the guaranteed power limit release state may be a state in which the wireless power receiver stops controlling the charging power supplied by the wireless power transmitter due to an event.

In addition, the wireless charging method according to the embodiment, the first power transmission contract change step, the power transmission stop step; Reconnecting with the wireless power receiver; Receiving a generic request packet requesting a power transmitter capability packet for a power transfer contract after transitioning to a negotiation step; And transmitting a power transmitter capability packet including a second guaranteed power value in response to the general request packet.

In addition, the wireless charging method according to the embodiment, the second step of changing the power transmission contract, power transmission stop step; Reconnecting with the wireless power receiver; Receiving a generic request packet requesting a power transmitter capability packet for a power transfer contract after transitioning to a negotiation step; And transmitting a power transmitter capability packet including a first guaranteed power value in response to the general request packet.

In addition, the wireless charging method according to the embodiment, the first step of changing the power transmission contract, the step of transitioning to the renegotiation step; Receiving a generic request packet requesting a power transmitter capability packet for a power transfer contract after a transition to a renegotiation step; And transmitting a power transmitter capability packet including a second guaranteed power value in response to the general request packet.

In the wireless charging method according to the embodiment, the transition to the renegotiation step may include transmitting a NAK packet when receiving a received power packet from a wireless power receiver.

In addition, the wireless charging method according to the embodiment, the second step of changing the power transmission contract, transitioning to the renegotiation step; Receiving a generic request packet requesting a power transmitter capability packet for a power transfer contract after a transition to a renegotiation step; And transmitting a power transmitter capability packet including a first guaranteed power value in response to the general request packet.

In the wireless charging method according to the embodiment, the transition to the renegotiation step may include transmitting a NAK packet when receiving a received power packet from a wireless power receiver.

In accordance with another aspect of the present invention, there is provided a wireless power transmitter including: a power transmitter including at least one transmitting coil and a driver controlling an output power provided to the at least one transmitting coil; A power converter converting the intensity of power applied from the outside to provide the output power; And a controller configured to control a charging mode and charging power for the wireless power receiver, wherein the charging mode includes a first charging mode and a second charging mode, and the controller is in a charging mode while performing charging in the second charging mode. The controller determines whether the battery is in a limited state, and the controller performs a first charging mode changing from the second charging mode to the first charging mode when the charging mode is limited, and the controller controls the first charging mode by changing the charging mode. The controller may determine whether the charging mode restriction release state is performed while the charging operation is performed, and when the charging mode restriction release state is performed, the controller may perform a second charging mode change from the first charging mode to the second charging mode.

In addition, in the wireless power transmitter according to the embodiment, the first charging mode is a low power charging mode, the second charging mode is a high power charging mode, and the charging mode restriction state is caused by an event of the wireless power receiver. The control mode is a state of controlling to reduce the intensity of the charging power to be supplied, wherein the charge mode restriction release state is a state in which the wireless power receiver stops the control of the charging power supplied by the wireless power transmitter due to an event, and the control unit limits the charging mode. State to provide a higher charging power to the wireless power receiver in a first charging mode than a second charging mode, and the controller is configured to provide higher charging power in a second charging mode than a first charging mode when the charging mode is restricted. It may be provided to the wireless power receiver.

In addition, the wireless power transmitter according to the embodiment further includes a sensing unit having a current sensor, the current sensor senses a driving current applied to the driving unit, the control unit is the sensed drive current value is the first threshold current value When the first state below is maintained for a first time, it is determined that the charging mode is restricted. When the second state where the sensed driving current value is greater than or equal to a second threshold current value is maintained for a second time, the charging mode limitation is released. It can be determined that the state.

In addition, the wireless power transmitter according to the embodiment, the first change of the charging mode, the control unit reconnects to the wireless power receiver after stopping the power transmission in the second charging mode, requesting the second charging mode received from the wireless power receiver The charging may be performed in the first charging mode ignoring the first response packet.

In addition, in the first change of the charging mode, the wireless power transmitter according to the embodiment may ignore the first response packet if the reconnection time taken for the reconnection is within a critical reconnection time.

In addition, the wireless power transmitter according to the embodiment further includes a sensing unit having an operating frequency sensor, the operating frequency sensor senses the operating frequency of the output power provided to the at least one transmitting coil, the control unit is the sensed operation If the third state having the frequency value equal to or greater than the first threshold frequency value is maintained for the third time, it is determined that the charging mode is restricted, and the controller determines that the fourth state where the sensed operating frequency value is equal to or less than the second threshold frequency value is fourth; If it is maintained for a period of time, it may be determined that the charging mode is restricted.

The wireless power transmitter may further include a sensing unit including an operating frequency sensor and an operating duty ratio sensor, wherein the operating frequency sensor senses an operating frequency of output power provided to the one or more transmitting coils, and operates The duty ratio sensor senses an operating duty ratio of the output power provided to the at least one transmitting coil, and the controller is configured such that the sensed operating frequency value is greater than or equal to a third threshold frequency value and the sensed operating duty ratio is a first threshold duty ratio. When the fifth state, which is less than or equal to the fifth state, is determined to be in a charging mode restriction state, the controller determines that the sensed operating duty ratio of which the sensed operating frequency value is less than or equal to a fourth threshold frequency value is greater than or equal to a second threshold duty ratio When the state is maintained for the sixth time, it may be determined that the charging mode is restricted.

In addition, the wireless power transmitter according to the embodiment changes the first charging mode, the control unit reconnects to the wireless power receiver after stopping power transmission in the second charging mode, and does not transmit the first packet indicating the second charging mode support. The charging may be performed in the first charging mode.

In addition, in the first change of the charging mode, the wireless power transmitter according to the embodiment may ignore the first response packet if the reconnection time is within a threshold reconnection time.

In addition, the wireless power transmitter according to the embodiment, if the second change of the charging mode, when the control unit receives a first response packet requesting the second charging mode from the wireless power receiver after transmitting the first packet indicating the second charging mode support. Charging may be performed in the second charging mode.

In accordance with another aspect of the present invention, there is provided a wireless power transmitter including: a power transmitter including at least one transmitting coil and a driver controlling an output power provided to the at least one transmitting coil; A power converter converting the intensity of DC power applied from the outside to provide the output power; A communication unit exchanging information with an external device; And a control unit for transmitting a packet through the communication unit to change a power transmission contract for guaranteed power which is a power intensity value transmitted by the power transmitter in a power transmission step, wherein the guaranteed power includes a first guaranteed power and a second guaranteed power. And the control unit determines whether a guaranteed power limit state is being performed while charging with the first guaranteed power, and wherein the control unit changes from the first guaranteed power to the second guaranteed power when the guaranteed power limited state. Perform the change, and the controller determines whether the guaranteed power limit release state is being performed while charging with the second guaranteed power by the first change of the power transmission contract; A second change in the power transfer agreement that changes to the 1 guaranteed power may be performed.

In addition, in the wireless power transmitter according to the embodiment, the first guaranteed power is high power, the second guaranteed power is low power, and the guaranteed power limited state is charged by the wireless power receiver by the wireless power transmitter due to an event of the wireless power receiver. The control power is controlled to reduce the strength of the control unit, and the guaranteed power limit release state is a state in which the wireless power receiver stops controlling the charging power supplied by the wireless power transmitter due to an event, and the controller controls the first control unit to set the guaranteed power limit state. Provide the wireless power receiver with a higher charging power at a second guaranteed power than the guaranteed power, and wherein the controller is configured to provide higher charging power at a first guaranteed power than a second guaranteed power when the guaranteed power is de-restricted. Can be provided to

In addition, the wireless power transmitter according to the embodiment, the first change in the power transmission contract, the control unit reconnects to the wireless power receiver after stopping the power transmission at the first guaranteed power, and transmits a power transmitter capability packet including a second guaranteed power value. And performing charging at a second guaranteed power, wherein the second change of the power transmission contract is performed by the control unit reconnecting with the wireless power receiver after the power transmission stops at the first guaranteed power, and including the first guaranteed power value. It may be to transmit a transmitter capability packet to perform charging at a second guaranteed power.

In addition, the wireless power transmitter according to the embodiment, the first change in the power transmission contract, the control unit reconnects to the wireless power receiver after the power transmission stops at the first guaranteed power, the second guaranteed power value is included after the transition to the renegotiation step Transmitting a power transmitter capability packet to perform charging with a second guaranteed power, wherein the second change of the power transfer contract is such that the control unit reconnects to the wireless power receiver after stopping power transmission at the first guaranteed power and transitions to a renegotiation step. Thereafter, the power transmitter capability packet including the first guaranteed power value may be transmitted to perform charging with the second guaranteed power.

In addition, when the wireless power transmitter transitions to the renegotiation step, when receiving a received power packet from the wireless power receiver, the wireless power transmitter may transmit a NAK packet.

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 receiver.

In addition, the present invention allows the wireless power receiver to control the charging power.

In addition, the present invention allows the wireless power transmitter to control the charging power.

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

In addition, the present invention can reduce the heat generation of the wireless power receiver and at the same time increase the charging speed.

In addition, the present invention can protect the load by controlling the charging power.

In addition, the present invention can increase the charging speed while protecting the load.

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

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

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

FIG. 5 is a circuit diagram illustrating a structure of a sensing unit of the wireless power transmitter according to FIG. 4.

FIG. 6 is a block diagram illustrating a structure of a wireless power receiver interworking with the wireless power transmitter according to FIG. 4.

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

8 illustrates a packet format according to a wireless power transmission procedure according to an embodiment.

9 is a diagram illustrating a type of a packet that can be transmitted in a ping step by a wireless power receiver according to a wireless power transmission procedure according to an embodiment.

10 illustrates a message format of an identification packet according to a wireless power transmission procedure according to an embodiment.

11 illustrates a message format of a configuration packet and a power control suspend packet according to a wireless power transmission procedure according to an embodiment.

12 illustrates a structure of a charging mode packet for requesting a charging mode change according to a wireless power transmission procedure according to an embodiment.

FIG. 13 is a diagram for describing a type of a packet that can be transmitted in a power transmission step and a message format thereof by a wireless power receiver according to a wireless power transmission procedure according to one embodiment.

14 is a diagram illustrating a charging mode state for explaining switching of a charging mode, according to an exemplary embodiment.

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

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

FIG. 17 is a graph illustrating a change in charge rate of a battery that is a load and a change in driving current of a wireless power transmitter according to a heat generation phenomenon during charging in a second charging mode.

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

FIG. 19 is a diagram illustrating an example of determining a charging mode restriction state of FIG. 18.

20 is a view for explaining an embodiment of the first charging mode change of FIG. 18 in the wireless charging system.

FIG. 21 is a diagram for describing an embodiment of a first charging mode change of FIG. 18 in a wireless power transmitter.

FIG. 22 is a diagram for describing an exemplary embodiment of determining a charge mode restriction release state of FIG. 18.

FIG. 23 is a diagram for describing an exemplary embodiment of a second change of the charging mode of FIG. 18 on a wireless charging system.

FIG. 24 is a graph illustrating a change in charge rate of a battery that is a load and a change in driving current of a wireless power transmitter according to a heat generation phenomenon during charging in a second charging mode in the wireless power transmitter of FIG. 18.

FIG. 25 is a graph illustrating a charging rate with time to explain the graph of FIG. 24.

FIG. 26 is a graph illustrating a change in charge rate of a battery that is a load and a change in driving current of the wireless power transmitter as the wireless power transmitter of FIG. 18 approaches the charging completion state during charging in the second charging mode.

27 is a view for explaining another embodiment of determining the charging mode restriction state of FIG. 18.

28 is a view for explaining another embodiment of determining the charge mode restriction release state of FIG. 18 when the determination of the charge mode restriction state according to FIG. 27 is performed.

FIG. 29 is a diagram for describing another embodiment of determining the charging mode restriction state of FIG. 18.

30 is a view for explaining another embodiment of determining the charge mode restriction release state of FIG. 18 when the determination of the charge mode restriction state according to FIG. 29 is performed.

31 is a view for explaining another embodiment of the first change of the charging mode of FIG. 18 on the wireless charging system.

32 is a view for explaining another embodiment of the first change of the charging mode of FIG. 18 in the wireless power transmitter.

33 is a view for explaining another embodiment of the second change of the charging mode of FIG. 18 on the wireless charging system.

34 is a view for explaining another embodiment of the second charging mode change of FIG. 18 in the wireless power transmitter.

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

36 is a diagram for describing a wireless charging method in a wireless power transmitter, according to another 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 (Bottom) "and" before (front) or after (back) "both include direct contact with one another or one or more other components disposed between 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 toothbrushes, electronic tags, lighting devices, remote controls, fishing bobbers, etc., but is not limited thereto.決 ◎)), and the term terminal or device can 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.

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

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 an application being executed, CPU usage information, battery charge status information, battery output voltage / current information, temperature information, and the like. However, the present invention is not limited thereto, and may be information obtained from the electronic device 30 and available for wireless power control.

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

Referring to FIG. 2, power transmission from a transmitter to a receiver according to the first wireless power transmission procedure of the WPC standard is largely selected in a selection phase 210, a ping phase 220, and an identification and identification step. and Configuration Phase, 230), and a power transfer phase (240).

The selection step 210 may be a step of transitioning 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 210, 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 220 (S201). In the selection step 210, the transmitter transmits an analog ping signal of a very short pulse, and detects 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 220, 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 to the digital ping (eg, signal strength indicator) from the receiver in the ping step 220, it may transition back to the selection step 210 (S202). In addition, in the ping step 220, when the transmitter receives a signal indicating that the power transmission is completed, that is, the charging completion signal, the transmitter may transition to the selection step 210 (S203).

When the ping step 220 is completed, the transmitter may transition to the identification and configuration step 230 for collecting receiver identification and receiver configuration and status information (S204).

In the identification and configuration step 230, 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 210 (S205).

When the identification and configuration of the receiver is completed, the transmitter may transition to the power transmission step 240 for transmitting the wireless power (S206).

In the power transmission step 240, the transmitter receives an unexpected packet, an outgoing desired packet for a predefined time, or a violation of a preset power transmission contract. transfer contract violation), if the filling is completed, the transition to the selection step (210) (S207).

In addition, in the power transmission step 240, 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 230 (S208).

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.

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

Referring to FIG. 3, power transmission from a transmitter to a receiver according to the second wireless power transmission procedure of the WPC standard is largely performed in a selection phase 310, a ping phase 320, and an identification and configuration step. and Configuration Phase (330), Negotiation Phase (340), Calibration Phase (Calibration Phase, 350), Power Transfer Phase (Power Transfer Phase, 360) and Renegotiation Phase (370). .

The selection step 310 transitions if a specific error or a specific event is detected while initiating or maintaining the power transmission—for example, including the reference numerals S302, S304, S308, S310, and S312. Can be. Here, specific errors and specific events will be apparent from the following description. In addition, in the selection step 310, 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 ping step 320. In the selection step 310, 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

When an object is detected in the selection step 310, the wireless power transmitter may measure a quality factor of a wireless power resonant circuit, eg, a transmission coil and / or a resonant capacitor for wireless power transmission.

 The wireless power transmitter can measure the inductance of a wireless power resonant circuit (eg, a power transfer coil and / or resonant capacitor).

The quality factor and / or inductance may be used to determine the presence or absence of foreign matter in a future negotiation step 340.

When an object is detected in the ping step 320, the transmitter wakes up the receiver and transmits a digital ping for identifying whether the detected object is a wireless power receiver (S301). If in ping step 320 the transmitter does not receive a response signal (eg, a signal strength packet) to the digital ping from the receiver, it may transition back to selection step 310. In addition, in the ping step 320, when the transmitter receives a signal indicating that the power transmission is completed, that is, a charging completion packet, the transmitter may transition to the selection step 310 (S302).

When the ping step 320 is completed, the transmitter may transition to the identification and configuration step 330 for identifying the receiver and collecting receiver configuration and status information (S303).

In the identification and configuration step 330, the sender 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 310 (S304).

The transmitter may determine whether entry into the negotiation step 340 is required based on a negotiation field value of the configuration packet received in the identification and configuration step 330.

As a result of the check, if negotiation is necessary, the transmitter may enter a negotiation step 340 (S305). In negotiation step 340, the transmitter may perform a predetermined FOD detection procedure.

On the other hand, if it is determined that negotiation is not necessary, the transmitter may immediately enter the power transmission step 360 (S306).

In the negotiation step 340, the transmitter may receive a Foreign Object Detection (FOD) status packet including a reference quality factor value. Alternatively, the FOD status packet including the reference inductance value may be received. Alternatively, a status packet including a reference quality factor value and a reference inductance value may be received. In this case, the transmitter may determine the quality factor threshold for FO detection based on the reference quality factor value. The transmitter may determine an inductance threshold for FO detection based on the reference inductance value.

The transmitter may detect whether the FO is present in the charging region using the quality factor threshold for the determined FO detection and the currently measured quality factor value, which may be, for example, the quality factor value measured before the ping step. Power transmission may be controlled according to the detection result. For example, when the FO is detected, power transmission may be stopped, but is not limited thereto.

The transmitter can detect whether the FO is present in the charging region using the inductance threshold for the determined FO detection and the current measured inductance value, which may be, for example, the inductance value measured prior to the ping step. Accordingly, power transmission can be controlled. 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 310 (S308). On the other hand, if the FO is not detected, the transmitter may enter the power transmission step 360 through the correction step 350 (S307 and S309). 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 350, and determines the power loss at the receiving end and the transmitting end to determine the strength of the power transmitted at 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 350. The transmitter according to an embodiment may correct the threshold for FOD detection by reflecting the predicted power loss.

In the power transmission step 360, 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 completed, the transition to the selection step 310 (S310).

In addition, in the power transmission step 360, 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 370 (S311). At this time, if the renegotiation is normally completed, the transmitter may return to the power transmission step 360 (S313).

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.

If the renegotiation is not normally completed, the transmitter may stop the power transmission to the corresponding receiver and transition to the selection step 310 (S312).

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

Referring to FIG. 4, the wireless power transmitter 400 largely includes a power converter 410, a power transmitter 420, a communication unit 430, a controller 440, a sensing unit 450, and a storage unit 470. It can be configured to include. It should be noted that the configuration of the wireless power transmitter 400 is not necessarily required, and may include more or fewer components.

As shown in FIG. 4, when power is supplied from the power supply unit 460, the power converter 410 may perform a function of converting the power into power of a predetermined intensity.

To this end, the power converter 410 may include a DC / DC converter 411 and an amplifier 412.

The DC / DC converter 411 may perform a function of converting DC power supplied from the power supply unit 460 into DC power having a specific intensity according to a control signal of the controller 440.

The amplifier 412 may adjust the intensity of the DC / DC converted power according to the control signal of the controller 440. For example, the controller 440 may receive power reception state information and / or power control signal of the wireless power receiver through the communication unit 430, and may be based on the received power reception state information or (and) power control signal. The amplification factor of the amplifier 412 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 420 may include a driver 421 and a transmission coil 422.

In addition, the driver 421 may include a multiplexer (or multiplexer) (not shown) and a carrier generator (not shown) for generating a specific operating frequency and a specific duty ratio for power transmission. For example, the carrier generator may generate a specific frequency for converting the output DC power of the amplifier 412 received through the multiplexer into AC power having a specific frequency. In one example, 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 412. Note that it may be mixed at the stage or after.

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 the resonant frequency for each transmitting coil equally or differently.

As shown in FIG. 4, the power transmitter 420 may include a multiplexer of the driver 421 and a plurality of transmit coils 422-that is, a second controller for controlling the output power of the amplifier 412 to be transmitted to the transmit coil. 1 to n-th transmit coils.

The sensing unit 450 may include at least one of a current sensor, a voltage sensor, a temperature sensor, an operating frequency sensor, and a duty ratio sensor.

More specifically, the sensing unit 450 may measure the current of the DC-converted power by the power change unit 410 using the current sensor and provide it to the controller 440. In addition, the sensing unit 450 may measure the voltage of the power DC converted by the power change unit 410 to the controller 440 by using the voltage sensor. In addition, the sensing unit 450 may measure the internal temperature of the wireless power transmitter 400 to determine whether overheating occurs using a temperature sensor, and provide the measurement result to the controller 440. In addition, the sensing unit 450 may measure and provide an operating frequency of AC power delivered to the transmitting coil 422 to the controller 440 using an operating frequency sensor. In addition, the sensing unit 450 may measure the duty ratio of the AC power delivered to the transmission coil 422 using the duty ratio sensor and provide it to the controller 440.

For example, the controller 440 may be adaptively selected from the power supply unit 450 based on at least one of a voltage value, a current value, an internal temperature value, an operating frequency value and a duty ratio value measured by the sensing unit 450. The power supply of the may be cut off, or the power supply to the amplifier 412 may be cut off. To this end, one side of the power converter 410 may be further provided with a predetermined power cut-off circuit for cutting off the power supplied from the power source 450, or cut off the power supplied to the amplifier 412.

As another example, the controller 440 may be based on any one or more of a current value, an operating frequency value, and a duty ratio value measured by the sensing unit 450 in the power transmission step according to the first wireless power transmission procedure of FIG. 2. It may be determined whether the charging mode is restricted. The charging mode includes a first charging mode and a second charging mode in which the intensity of the transmission power is greater than the first charging mode according to the power transmission contract. A more detailed description of the charging mode will be given later. The wireless power receiver may control the charging power transmitted from the wireless power transmitter as an event occurs. An example of an event occurring in the wireless power receiver may be a sudden temperature rise or high temperature of the wireless power receiver or load, for example a battery. As another example of the event, the state of charge of the battery may be close to full charge. In addition, the charging power controlled by the wireless power receiver may be changed according to the charging mode. For example, when the event occurs, the wireless power receiver may control the charging power so that the lower power is transmitted in the second charging mode in which the contracted transmission power is greater than the first charging mode. The charging mode restriction state may be a state that is restricted to perform charging in a specific charging mode. More specifically, the charging mode restriction state may be a state that must be controlled to perform charging in the first charging mode. In addition, the charging mode limitation state may be a state in which the strength of power that can be transmitted in the second charging mode is smaller than in the first charging mode according to the charging power control due to the event of the wireless power receiver. A more detailed description of the charging mode restriction state may be based on the wireless charging method of the wireless power transmitter described later. In addition, the controller 440 may perform the first charging mode changing to the first charging mode when it is determined that the charging mode is restricted while the second charging mode is being performed. A detailed description of the first change of the charging mode may be based on the wireless charging method of the wireless power transmitter described later. In addition, the controller 440 is charged based on any one or more of a current value, an operating frequency value, and a duty ratio value measured by the sensing unit 450 in the power transmission step according to the first wireless power transfer procedure of FIG. 2. It may be determined whether the mode is restricted. The charge mode restriction release state may be a state in which the restriction to perform charging in a specific charge mode is released. More specifically, the charge mode restriction release state is a state in which the event is terminated and the charging power control of the wireless power receiver due to the event is terminated. That is, the charging mode restriction release state may be a state in which the second charging mode may transmit power of greater intensity than the first charging mode. A more detailed description of the charge mode restriction release state may be based on the wireless charging method of the wireless power transmitter described below. In addition, the controller 440 may perform a second change of the charging mode to change to the second charging mode when it is determined that the charging mode is restricted while the charging is performed in the first charging mode. A detailed description of the second change of the charging mode may be based on the wireless charging method of the wireless power transmitter described later.

As another example, the controller 440 may be based on any one or more of a current value, an operating frequency value, and a duty ratio value measured by the sensing unit 450 in the power transmission step according to the second wireless power transmission procedure of FIG. 3. It may be determined whether the guaranteed power limit state. The guaranteed power 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 by a power transmission contract. Detailed description of the guaranteed power will be described later. In addition, the charging power controlled by the wireless power receiver may be changed according to the guaranteed power. For example, the guaranteed power may include a first guaranteed power having a relatively large guaranteed power value and a second guaranteed power having a relatively small guaranteed power value. The wireless power receiver may control the charging power transmitted from the wireless power transmitter as an event occurs. An example of an event occurring in the wireless power receiver may be a sudden temperature rise or high temperature of the wireless power receiver or load, for example a battery. As another example of the event, the state of charge of the battery may be close to full charge. In addition, the charging power controlled by the wireless power receiver may be changed according to the charging mode. For example, the wireless power receiver may control the charging power so that when the event occurs, performing the charging with the first guaranteed power is transmitted as compared with performing the charging with the second guaranteed power. . The guaranteed power limit state may be a state limited to perform charging with a certain guaranteed power strength. In the guaranteed power limit state, when the power transmission contract is made with a relatively high guaranteed power value than when the power transmission contract is made with a relatively low guaranteed power value according to the charging power control of the wireless power receiver due to the event, the strength of the transmission power is higher It may be small. That is, although the guaranteed power value is high, the strength of the transmit power may be lower than when the guaranteed power value is low due to the charging power control of the wireless power receiver. A more detailed description of the guaranteed power limit state may follow a wireless charging method of the wireless power transmitter described below. In addition, when the controller 440 determines that the guaranteed power limited state during charging is performed with the first guaranteed power having a relatively large guaranteed power value, the controller 440 changes the first power transmission contract to a second guaranteed power having a relatively small guaranteed power value, or The third modification to the power transfer agreement may be performed. A detailed description of the first change of the power transmission contract and the third change of the power transmission contract may be based on the wireless charging method of the wireless power transmitter, which will be described later. In addition, the controller 440 may be guaranteed based on any one or more of a current value, an operating frequency value, and a duty ratio value measured by the sensing unit 450 in the power transmission step according to the second wireless power transmission procedure of FIG. 3. It may be determined whether the power limitation is released. The guaranteed power limit release state may be a state in which the restriction to perform charging with a specific guaranteed power is released. More specifically, the guaranteed power limit release state is a state in which the event is terminated and charging power control due to the event of the wireless power receiver is terminated. That is, the guaranteed power limit release state may be a state in which the intensity of power that can be transmitted in the first guaranteed power is greater than the intensity of power that can be transmitted in the second guaranteed power. A more detailed description of the guaranteed power limit release state may follow a wireless charging method of the wireless power transmitter, which will be described later. In addition, the controller 440 may perform a second power transfer contract change or a fourth power transfer contract change to the first guaranteed power when it is determined that the guaranteed power limit is released during charging with the second guaranteed power. A detailed description of the second change of the power transmission contract or the fourth change of the power transmission contract may be based on the wireless charging method of the wireless power transmitter described later.

The storage unit 470 stores a threshold current, a threshold operating frequency, a threshold duty ratio, and the like, which are used to determine a charging mode limitation state determination, a charging mode limitation release state determination, a guaranteed power limitation state determination, or a guaranteed power limitation release state determination. Can be. In addition, the storage unit 470 may store the reconnection time used to change the charging mode or the power transmission contract, whether the charging mode is limited before reconnection, or whether the guaranteed power is limited before reconnection.

According to an embodiment, when a plurality of wireless power receivers are connected, the controller 440 may transmit power through time division multiplexing for each transmission coil. For example, three wireless power receivers, i.e., the first to third wireless power receivers, are identified in the wireless power transmitter 400 through three different transmitting coils, i.e., the first to third transmitting coils, respectively. In this case, the controller 440 may control the multiplexer of the driver 421 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 412 of the wireless power receiver may be controlled to transmit power.

The controller 440 may control the multiplexer of the driver 421 to sequentially transmit the detection signals through the first to nth transmission coils 422 during the first detection signal transmission procedure. In this case, the controller 440 may identify a time point at which the detection signal is transmitted by using the timer 455. When the detection signal transmission time arrives, the control unit 440 controls the multiplexer 421 to detect the detection signal through the corresponding transmission coil. Can be controlled to be sent. For example, the timer 450 may transmit a specific event signal to the controller 440 at a predetermined period during the ping transmission step. When the corresponding event signal is detected, the controller 440 controls the multiplexer 421 to transmit the specific event signal. The digital ping can be sent through the coil.

In addition, the control unit 440 may identify a predetermined transmission coil identifier and a corresponding transmission coil for identifying which transmission coil has received a signal strength indicator from the demodulator 432 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 440 controls the multiplexer of the driving unit 421 so that the detection signal is transmitted only through the transmission coil (s) in which the signal strength indicator is received during the first detection signal transmission procedure. You can also control it. As another example, when there are a plurality of transmitting coils receiving the signal strength indicator during the first sensing signal transmitting procedure, the controller 440 sends the second sensing signal to the transmitting coil in which the signal strength indicator having the largest value is received. In the procedure, the sensing signal may be determined as the transmission coil to be transmitted first, and the multiplexer of the driver 421 may be controlled according to the determination result.

The modulator 431 may modulate the control signal generated by the controller 440 and transmit the modulated control signal to the driver 421. 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 432 may demodulate the detected signal and transmit the demodulated signal to the controller 440. 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 432 may identify from which transmission coil the demodulated signal is received, and may provide the control unit 440 with a predetermined transmission coil identifier corresponding to the identified transmission coil.

 For example, the wireless power transmitter 400 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 400 may transmit wireless power using the transmission coil 422 and may exchange various information with the wireless power receiver through the transmission coil 422. As another example, the wireless power transmitter 400 further includes a separate coil corresponding to each of the transmission coils 422 (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. 4, the wireless power transmitter 400 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.

FIG. 5 is a circuit diagram illustrating a current sensor of a sensing unit of the wireless power transmitter according to FIG. 4.

Referring to FIG. 5, the sensing unit 450 may include a current sensor 500. The current sensor 500 may sense the driving current Id and provide the sensed sensing voltage Vsense to the controller 440. The driving current Id may be a current flowing from the power converter 410 to the driver 421. The present invention is not limited thereto, and the current sensor 500 may measure a current at a specific node, a specific component, a specific position, or the like of the wireless power transmitter.

The current sensor 500 may include a sensing resistor R1, a first auxiliary capacitor C1, a second auxiliary capacitor C2, and an amplifier 510. More specifically, the sensing resistor R1 may generate a voltage difference by the driving current Id and input the generated voltage difference to the amplifier 510. The sensing resistor R1 may be connected in series between the power converter 410 and the driver 421. Both ends of the sensing resistor R1 may be input to the non-inverting input terminal IN + and the inverting input terminal IN− of the amplifier 510, respectively. The first auxiliary capacitor C1 may store the voltage at both ends of the sensing resistor R1 to increase the accuracy of the sensing measurement. The first auxiliary capacitor C1 may be connected in parallel with the sensing resistor R1. The amplifier 510 may amplify the voltage difference input by the sensing resistor R1 to a gain A and output the same as the sensing voltage Vsense. The amplifier 510 may be driven by receiving a driving voltage Vcc and a ground power source. The second auxiliary capacitor C2 may remove noise of the driving voltage Vcc input to the amplifier 510. One end of the second auxiliary capacitor C2 may be connected to an input terminal of the driving voltage Vcc of the amplifier 510, and the other end thereof may be connected to a ground power source.

FIG. 6 is a block diagram illustrating a structure of a wireless power receiver interworking with the wireless power transmitter according to FIG. 4.

Referring to FIG. 6, the wireless power receiver 600 includes a receiving coil 610, a rectifier 620, a DC / DC converter 630, a load 640, a sensing unit 650, and a communication unit ( 660, the main control unit 670 may be configured. Herein, the communication unit 660 may include at least one of a demodulator 661 and a modulator 662.

Although the wireless power receiver 600 illustrated in the example of FIG. 6 is illustrated as being capable of exchanging information with the wireless power transmitter 400 through in-band communication, this is only one embodiment. The communication unit 660 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 610 may be transferred to the rectifier 620. The rectifier 620 may convert AC power into DC power and transmit the DC power to the DC / DC converter 630. The DC / DC converter 630 may convert the strength of the rectifier output DC power into a specific strength required by the load 640 and then transfer the power to the load 640. In addition, the receiving coil 610 may be configured to include a plurality of receiving coils (not shown), that is, the first to n-th receiving coil. 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 650 may measure the intensity of the rectifier 620 output DC power and provide the same to the main controller 670. In addition, the sensing unit 650 may measure the strength of the current applied to the receiving coil 610 according to the wireless power reception, and may transmit the measurement result to the main controller 670. In addition, the sensing unit 650 may measure the internal temperature of the wireless power receiver 600 and provide the measured temperature value to the main controller 670.

The main controller 670 may determine whether the overvoltage is generated 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 662. Here, the signal modulated by the modulator 662 may be transmitted to the wireless power transmitter through the receiving coil 610 or a separate coil (not shown).

In addition, the main controller 670 may determine that the sensing signal is received when the intensity of the rectifier output DC power is greater than or equal to a predetermined reference value. When the sensing signal is received, a signal strength indicator corresponding to the sensing signal may be modulated by the modulator 662. Can be transmitted to the wireless power transmitter.

The demodulator 661 demodulates an AC power signal or a rectifier 620 output DC power signal between the receiving coil 610 and the rectifier 620 to identify whether a detection signal is received, and then identifies an identification result. Can be provided to In this case, the main controller 670 may control the signal strength indicator corresponding to the detection signal to be transmitted through the modulator 662.

In addition, the main controller 670 may be configured to change the charging mode or change the power transmission contract based on at least one of the battery charge rate, the internal temperature, the strength of the rectifier output voltage, the CPU usage of the electronic device, and the user menu selection. If it is determined whether the change of the charging mode is necessary or if the change of the power transmission contract is necessary, a charging mode packet including the changed charging mode value is generated and transmitted to the wireless power transmitter or a renegotiation packet is determined. It may be generated and transmitted to the wireless power transmitter.

In addition, the main controller 670 may determine whether overheating occurs by comparing the internal temperature value measured by the sensing unit 650 with a predetermined reference value. If overheating occurs during wireless charging, the main controller 670 may generate and transmit a power control packet to reduce the strength of the charging power transmitted from the wireless power transmitter. The power control packet may be a control error packet described later. For example, in the power transmission step according to the first wireless power transmission procedure of FIG. 2, the main controller 670 is set to have different charging power control values in the first charging mode and the second charging mode to transmit the power control packet. can do. The charging power control value in the second charging mode may have a greater reduction ratio of the intensity of the charging power transmitted compared to the charging power control value in the first charging mode. In addition, the charging power control value in the two charging modes may be smaller than the maximum value of the intensity of the charging power transmitted compared with the charging power control value in the first charging mode. As another example, in the power transmission step according to the second wireless power transmission procedure of FIG. 3, the main controller 670 is set to have different charging power control values in the first guaranteed power and the second guaranteed power to transmit the power control packet. can do. The charging power control value at the first guaranteed power may be greater in proportion to a reduction in the intensity of the charging power transmitted compared to the charging power control value at the second guaranteed power. Also, the charging power control value at the 1 guaranteed power can make the maximum value of the intensity of the charging power transmitted compared with the charging power control value at the second guaranteed power smaller. Accordingly, the main controller 670 may reduce heat generation of the wireless power receiver. In addition, it is possible to protect the internal devices by reducing the heat generation of the wireless power receiver.

In addition, the main controller 670 may control the strength of the charging power transmitted by the wireless power transmitter based on the battery charging rate. If it is determined that the battery charge rate is a buffer level compared to a predetermined reference value, the main controller 670 may generate and transmit a power control packet to reduce the strength of the charging power transmitted from the wireless power transmitter. The power control packet may be a control error packet described later. For example, in the power transmission step according to the first wireless power transmission procedure of FIG. 2, the main controller 670 is set to have different charging power control values in the first charging mode and the second charging mode to transmit the power control packet. can do. The charging power control value in the second charging mode may have a greater reduction ratio of the intensity of the charging power transmitted compared to the charging power control value in the first charging mode. In addition, the charging power control value in the two charging modes may be smaller than the maximum value of the intensity of the charging power transmitted compared with the charging power control value in the first charging mode. As another example, in the power transmission step according to the second wireless power transmission procedure of FIG. 3, the main controller 670 is set to have different charging power control values in the first guaranteed power and the second guaranteed power to transmit the power control packet. can do. The charging power control value at the first guaranteed power may be greater in proportion to a reduction in the intensity of the charging power transmitted compared to the charging power control value at the second guaranteed power. Also, the charging power control value at the 1 guaranteed power can make the maximum value of the intensity of the charging power transmitted compared with the charging power control value at the second guaranteed power smaller. Accordingly, the main controller 670 may protect the battery by reducing the charging power when the main controller 670 is close to the full charge of the battery.

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

As illustrated at 710 of FIG. 7, 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 6.

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 730. Referring to reference numeral 730, the byte encoding scheme according to an embodiment includes a start bit and a stop bit for identifying a start and a 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.

8 illustrates a packet format according to a wireless power transmission procedure according to an embodiment.

FIG. 8 may mainly be a packet format according to the first wireless power transfer procedure of FIG. 2. That is, the packet format of FIG. 8 may be a packet format also used for the second wireless evening transmission procedure of FIG. 3.

Referring to FIG. 8, the packet format 800 used for exchanging information between the wireless power transmitter 10 and the wireless power receiver 20 may be used to obtain synchronization for demodulation of the packet and to identify the correct start bit of the packet. Preamble (810) field, a header (Header, 820) field for identifying the type of the message included in the packet, a message for transmitting the contents (or payload) of the packet (Message, 830) and a checksum (840) field for identifying whether an error has occurred in the corresponding packet.

As shown in FIG. 8, the packet receiving end may identify the size of the message 830 included in the packet based on the header 820 value.

In addition, the header 820 may be defined in each step of the wireless power transfer procedure, and in part, the header 820 value may be defined as a different type of message although the same value is used in different steps. For example, referring to FIG. 8, it should be noted that the header values corresponding to the end power transfer of the ping step and the end of the power transfer of the power transfer step may be equal to 0x02.

The message 830 includes data to be transmitted at the transmitting end of the packet. For example, the data included in the message 830 field may be a report, a request, or a response to the counterpart, but is not limited thereto.

The packet 800 according to another embodiment may further include at least one of transmitter identification information for identifying a transmitter that transmitted the packet, and 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.

According to another embodiment, the packet 800 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.

9 is a diagram illustrating a type of a packet that can be transmitted in a ping step by a wireless power receiver according to a wireless power transmission procedure according to an embodiment.

As illustrated in FIG. 9, in the ping step, the wireless power receiver may transmit a signal strength packet or a power transmission stop packet.

Referring to reference numeral 901 of FIG. 9, a message format of a signal strength packet according to an embodiment 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 reference numeral 902 of FIG. 9, a message format of a power transmission interruption packet 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 stop power transmission is because of charge complete, 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 in response to each new power transfer abort 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.

10 illustrates a message format of an identification packet according to a wireless power transmission procedure according to an embodiment.

Referring to FIG. 10, a message format of an identification packet includes a version information field, a manufacturer information field, an extension indicator field, and a basic device identification information field. Can be configured.

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 an extension identification packet including extension device identification information exists. 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 1001 to 1002, when 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.

11 illustrates a message format of a configuration packet and a power control suspend packet according to a wireless power transmission procedure according to an embodiment.

As shown in reference numeral 1101 of FIG. 11, a message format of a configuration packet may have a length of 5 bytes, and includes a power class field, a maximum power field, and a power control field. , A count field, a window size field, a window offset 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.

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

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.

Referring to reference numeral 1102, a message format of a power control hold packet may be configured to include a power control hold time T_delay. A plurality of power control pending packets may be sent during the identification and configuration phase. For example, up to seven power control pending packets 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 last power control holding packet received in the identification and configuration step. In addition, the wireless power transmitter may use the T_min value as the T_delay value when the power control pending packet 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.

12 illustrates a structure of a charging mode packet for requesting a charging mode change according to a wireless power transmission procedure according to an embodiment.

Referring to FIG. 12, one of undefined values among packet header values defined in the current wireless charging standard may be used as a header value of a charging mode packet. For example, the header value of the charging mode packet may be defined as 0x18, as shown in FIG. 8, but it should be noted that this is for convenience of description and need not necessarily be the value.

The message size corresponding to the header value 0x18 may be 1 byte.

Information on a charging mode to be changed may be recorded in a message field of the charging mode packet. For example, referring to reference numeral 1210, when a change to the second charging mode is required during charging in the first charging mode, the wireless power receiver may record and transmit 0xff in a message field of the charging mode packet. On the other hand, if a change to the first charging mode is required during charging in the second charging mode, the wireless power receiver may write 0x00 in the message field of the charging mode packet and transmit the same. The example shown in reference numeral 1210 is only for the understanding of the present invention, but the message value is not necessarily defined as such.

FIG. 13 is a diagram for describing a type of a packet that can be transmitted in a power transmission step and a message format thereof by a wireless power receiver according to a wireless power transmission procedure according to one embodiment.

Referring to FIG. 13, a packet transmittable by a wireless power receiver in a power transmission step includes a control error packet (CEP), an end power transfer packet, a received power packet, It may include a Charge Status Packet, a packet defined by a manufacturer, and the like.

Reference numeral 1301 shows a message format of a control error packet composed of a control error value of 1 byte. Here, the control error value may be an integer value in the range of -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.

Reference numeral 1302 shows a message format of an End Power Transfer Packet composed of one byte of an End Power Transfer Code.

Reference numeral 1303 illustrates a message format of a received power packet composed of a received power value of 1 byte. Here, the received power value may correspond to the average rectifier received power value calculated during the predetermined period. Actually received power amount (Preceived) may be calculated based on the maximum power (Maximum Power) and power class (Power Class) included in the configuration packet 1301. For example, the actual received power amount may be calculated by (received power value / 128) * (maximum power / 2) * (10 power rating).

Reference numeral 1304 shows a message format of a charge status packet composed of a charge status value of 1 byte. 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.

14 is a diagram illustrating a charging mode state for explaining switching of a charging mode, according to an exemplary embodiment.

Referring to FIG. 14, the power transmission step 240 of FIG. 2 may include a first charging mode 1410 and a second charging mode 1420. For example, the first charging mode 1410 may be a case where charging is performed at a general low power. The second charging mode 1420 may be a case where charging is performed at high power.

The first charging mode 1410 and the second charging mode 1420 may be switched to each other when a predetermined condition is satisfied. For example, when the wireless power receiver receives a request for switching to the second charging mode 1420 from the electronic device while performing charging in the first charging mode 1410, the wireless power receiver notifies the wireless power transmitter of the switching to the second charging mode 1420. The charging mode may be changed by transmitting a request packet. As another example, the wireless power receiver may transmit a predetermined packet requesting the switch to the first charging mode 1410 to the wireless power transmitter when the battery charging amount reaches a predetermined reference value during the charging to the second charging mode 1420. have.

The wireless power transmitter according to another embodiment may transmit power to a plurality of wireless power receivers. In this case, when the wireless power receiver is newly connected or the connection with the existing wireless power receiver is released, a power redistribution procedure for the currently connected wireless power receiver (s) may be performed. If, as a result of the power redistribution, the wireless power transmitter can no longer provide high power to the wireless power receiver that is being charged in the second charging mode, the wireless power transmitter transmits the first charging mode 1410 in the second charging mode 1420 to the corresponding wireless power receiver. It may also send a predetermined packet requesting the switch to.

In the above exemplary embodiment, the charging mode is divided into the first charging mode 1410 and the second charging mode 1420. For example, the charging mode is only one embodiment, and a new charging mode (the third charging mode) is described. May be defined and added. For example, the second charging mode 1420 for fast charging may be subdivided into an intermediate power fast charging mode (not shown) and a high power fast charging mode (not shown). For example, the medium power fast charging mode (not shown) may output an average of 9W of power. The high power fast charging mode (not shown) can deliver an average power of 15W. Without being limited to the above example, the medium power fast charging mode (not shown) and the high power fast charging mode (not shown) may be defined in other meanings.

The initial charging mode may be determined by exchanging or negotiating state information between the wireless power transmitter and the wireless power receiver in the identification and configuration step 230 of FIG. 2.

For example, in the identifying and configuring step 230 of FIG. 2, the wireless power transmitter may transmit predetermined information for identifying whether the device is capable of supporting the second charging mode to the wireless power receiver. In this case, when the wireless power receiver is a device capable of the second charging mode and the battery charge amount is less than or equal to a predetermined reference value, the wireless power receiver may transmit a predetermined packet requesting the second charging mode to the wireless power transmitter. When the wireless power transmitter normally enters the power transmission step, the wireless power transmitter may switch to the second charging mode and perform wireless charging at the request of the wireless power receiver.

According to another embodiment, the initial charging mode may be determined in the power transmission step. For example, when the wireless power transmitter receives an initial power control request packet, for example, but not limited to, a Control Error Packet defined in the WPC standard, the wireless power transmitter enters a power transmission step and receives a first power control request packet. The first packet for identifying whether the second charging mode is supported may be transmitted. When the wireless power receiver receives the first packet and determines that the connected wireless power transmitter supports the second charging mode, the wireless power receiver determines whether to start charging in the second charging mode, and includes a predetermined first response packet including the determination result. May be transmitted to the wireless power transmitter. That is, the initial charging mode may be determined based on the first response packet.

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

Referring to FIG. 15, when the wireless power receiver enters a power transmission step, the wireless power receiver may collect its state information, that is, receiver state information (S1501).

The wireless power receiver may determine whether to change the charging mode based on the collected receiver state information (S1503 to S1505).

For example, the receiver state information may include battery charge state information. If the battery charge amount during charging in the first charging mode falls below a predetermined reference value, the wireless power receiver may determine that switching to the second charging mode is necessary.

 As another example, the receiver state information may include information regarding CPU usage. If the CPU consumption during the charging in the first charging mode exceeds a predetermined reference value and power consumption rapidly increases, the wireless power receiver may determine that the switching to the second mode is necessary.

As another example, the receiver state information may include application software and peripheral state information. As an example, when the number of application software currently running exceeds a predetermined reference value, the wireless power receiver may determine that switching to the second charging mode is necessary. For example, the peripheral device state information may include camera driving state information, fresh driving state information, speaker driving state information, and the like. The wireless power receiver may determine whether to switch to the second charging mode based on the driving state of the peripheral device.

As a result of the determination, when it is necessary to change the charging mode, the wireless power receiver may generate a predetermined charging mode packet including the charging mode value to be changed and transmit it to the wireless power transmitter (S1507).

If it is not necessary to change the charging mode in step 1505, the wireless power receiver may return to step 1501.

In the description of FIG. 15, the wireless power receiver determines whether to change the charging mode based on the receiver state information. However, this is only one embodiment. As another example, the wireless power receiver is a user interface of an electronic device. When switching to a specific charging mode is requested according to a predetermined user menu selection on the mobile terminal, a charging mode packet may be generated and transmitted to the wireless power transmitter requesting the switching to the corresponding charging mode.

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

In detail, FIG. 16 is a flowchart for describing a charging mode switching procedure in a wireless charging system.

Referring to FIG. 16, the wireless power transmitter 1610 receives a predetermined first packet indicating the second charging mode support when an initial control error packet is received from the wireless power receiver 1620 after the transition to the power transmission step in the identification and configuration steps. May be generated and transmitted to the wireless power receiver 1620 (S1601 to S1602). The wireless power receiver 1620 determines that the wireless power transmitter 1610 supports the second charging mode based on the received first packet, and when the wireless power receiver 1620 is a device capable of charging in the second charging mode, the second charging A predetermined first response packet requesting a mode may be generated and transmitted to the wireless power transmitter 1610 (S1603).

In operation S1604, charging may be started in the second charging mode by switching to the second charging mode. Here, although not shown, when switching from the first charging mode to the second charging mode, the charging mode may be switched after a predetermined charging mode change waiting time has elapsed. The charging mode change wait time may be predefined or determined by the wireless power receiver 1620 and then transmitted to the wireless power transmitter 1610 through a first response packet. In the second charging mode, the charging power transmitted from the wireless power transmitter 1610 may be controlled by the control error packet of the wireless power receiver 1620 (S1605). In particular, the wireless power receiver may control the charging power transmitted from the wireless power transmitter as an event occurs. An example of an event occurring in the wireless power receiver may be a sudden temperature rise or high temperature of the wireless power receiver or load, for example a battery. As another example of the event, the state of charge of the battery may be close to full charge. In addition, the wireless power receiver may further reduce the intensity of the charging power transmitted in the second charging mode than in the first charging mode to reduce the heat generation phenomenon. In addition, the wireless power receiver may further reduce the strength of the charging power transmitted in the second charging mode than in the first charging mode to protect the battery when the battery is in the fully charged phase.

FIG. 17 is a graph illustrating a change in charge rate of a battery that is a load and a change in driving current of a wireless power transmitter according to a heat generation phenomenon during charging in a second charging mode.

Referring to FIG. 17, when it is determined that the battery temperature a is a predetermined reference value, the wireless power receiver according to the exemplary embodiment of FIG. 16 may control charging power transmitted from the wireless power transmitter. In this case, the wireless power transmitter may reduce the driving current c to reduce the transmission power according to the charging power control of the wireless power receiver. For example, as shown in FIG. 17, the temperature of the battery in operation of the load during charging in the second wireless charging mode (for example, display on if the load is a mobile phone, application operation of the load in another example) May increase and the battery temperature a may reach a reference value at a first time point, that is, about 5 seconds. In this case, the wireless power receiver may transmit a control error packet for controlling the charging power to lower the battery temperature and reduce the transmission power from the first time point. The wireless power transmitter receives the control error packet at the first time point to reduce the drive current c.

However, although the battery is being charged in the second wireless charging mode due to the operation, it can be seen that the charging rate b of the battery is rather reduced from the first time point. This problem occurs because the power consumed by the load is greater than the charged power.

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

Referring to FIG. 18, in the power transmission step, the wireless power transmitter may perform charging in the second charging mode in operation S1801.

While charging in the second charging mode, the wireless power transmitter may determine whether the charging mode is restricted (S1802). The charging mode restriction state may be a state that is restricted to perform charging in a specific charging mode. More specifically, the charging mode restriction state may be a state that must be controlled to perform charging in the first charging mode. In addition, the charging mode limitation state may be a state in which the strength of power that can be transmitted in the second charging mode is smaller than in the first charging mode according to the charging power control due to the event of the wireless power receiver. For example, the event may be a heat generation phenomenon such as a sudden temperature rise or a high temperature state of a wireless power receiver or a load, for example, a battery. In addition, as another example of the event, the state of charge of the battery may be close to full charge.

If it is determined that the charging mode is restricted, the wireless power transmitter may perform the first charging mode changing from the second charging mode to the first charging mode in operation S1803. According to another embodiment, the wireless power transmitter has a greater power transfer contracted transmit power intensity in the second charging mode than in the first charging mode. However, in the charging mode limited state, due to the changed charging power control according to the charging mode of the wireless power receiver, since the actual transmitted power is smaller in the second charging mode than the first charging mode, the charging in the first charging mode is performed. By controlling, the charging speed of the battery can be increased. Therefore, the wireless power transmitter according to another embodiment may improve the heat generation phenomenon of the wireless power receiver and at the same time increase the charging speed. In addition, in the same principle, the wireless power transmitter according to another embodiment may increase the charging speed while protecting the battery in the battery's fully charged phase. If it is determined that the charging mode is not limited, the wireless power transmitter may perform charging in the second charging mode of S1801.

After the first change of the charging mode, the wireless power transmitter may perform charging in the first charging mode (S1804).

While charging in the first charging mode, the wireless power transmitter may determine whether the charging mode restriction release state (S1805).

If it is determined that the charging mode is restricted, the wireless power transmitter may perform a second charging mode change from the first charging mode to the second charging mode (S1806). That is, the wireless power transmitter according to another embodiment may perform the charging in the second charging mode to increase the charging speed when the charging mode restriction is canceled and the charging power control due to the event in the wireless power receiver is stopped. Therefore, the wireless power transmitter according to another embodiment may increase the charging speed by adaptively changing the charging mode according to the state of the wireless power receiver. If it is determined that the charging mode is not in a restricted state, the wireless power transmitter may perform charging in the first charging mode of S1804.

FIG. 19 is a diagram illustrating an example of determining a charging mode restriction state of FIG. 18.

A step S1802 of determining the charging mode restriction state of FIG. 18 will be described in more detail with reference to FIG. 19.

The charging mode restriction state determination may be performed in the step of the wireless power transmitter performing charging in the second charging mode (S1901).

The wireless power transmitter may sense a driving current (S1902). More specifically, as illustrated in FIGS. 4 and 5, the current sensor 500 of the sensing unit 450 may sense a driving current applied to the driving unit 4210.

In operation S1903, it is determined whether the sensed driving current is in a first state that is equal to or less than the first threshold current. The first state may be a state in which a value of the sensed driving current is equal to or less than a value of the first threshold current. The first threshold current may be a driving current value at which the charging rate of the battery begins to decrease even during wireless charging. More specifically, the first threshold current may be a driving current value when the charging rate of the battery begins to decrease due to an operation of consuming high power of the load while performing charging in the second charging mode. In addition, the first threshold current may be a preset current value. In addition, the first threshold current may be 300 mA or more and 350 mA or less. More specifically, the first threshold current may be 320 mA.

The wireless power transmitter may determine the first state and determine whether the first state is maintained for the first time (S1904). That is, the wireless power transmitter may determine whether the state where the value of the driving current is less than or equal to the value of the first threshold current is maintained for the first time. Accordingly, the wireless power transmitter may prevent an error of determining that the charging mode is restricted even though the first state occurs for a while and is not the charging mode limited state. The first time may be a time at which the charging rate of the battery is reduced by maintaining a first state in which the sensed driving current is less than or equal to the first threshold current to consume high power of the load while performing charging in the second charging mode. In addition, the first time may be a preset time. In addition, the first time may be 1 second or more and 10 seconds or less. More specifically, the first time may be 5 seconds.

If the first state is maintained for the first time, the wireless power transmitter may determine that the charging mode is restricted (S1905). The wireless power transmitter is not limited thereto and may determine that the wireless power transmitter is in the charging mode limited state. In this case, the process proceeds from S1903 to S1905.

If it is not the first state or the first state is not maintained for the first time, the wireless power transmitter may determine that the charging mode is not in the restricted mode (S1906).

If the wireless power transmitter determines that the charging mode is restricted, the wireless power transmitter may store the current charging mode limited state in the storage unit 470. In this case, the wireless power transmitter may check the stored charging mode restriction state to perform the first charging mode change of S1803. In addition, if it is determined that the wireless power transmitter is not in the limited charging mode, the wireless power transmitter may perform charging in the second charging mode of S1803 (S1907).

20 is a view for explaining an embodiment of the first charging mode change of FIG. 18 in the wireless charging system.

Referring to FIG. 20, if the wireless power transmitter 2010 determines that the charging mode is restricted while performing charging in the second charging mode, the wireless power transmitter 2010 may stop power transmission (S2001). Thereafter, the wireless power transmitter 2010 may proceed with the first wireless power transmission procedure in order of selection, ping, identification and configuration, and power transmission. As an example, the reconnection time may be a time until the signal strength packet is received by the wireless power receiver 2020 after the power transmission stops. As another example, the reconnection time may be a time until the reception of the identification packet of the wireless power receiver 2020 after the power transmission stops. As another example, the first reconnection time may be a time until the reception of the configuration packet of the wireless power receiver 2020 after the power transmission stops.

The wireless power transmitter 2010 generates a predetermined first packet informing of the second charging mode support when an initial control error packet is received from the wireless power receiver 2020 after the transition to the power transmission phase in the identification and configuration phases. 2020 may be transmitted (S2002 to S2003).

The wireless power receiver 2020 determines that the wireless power transmitter 2010 supports the second charging mode based on the received first packet, and when the wireless power receiver 2020 is a device capable of charging in the second charging mode, the second charging In operation S2004, a predetermined first response packet may be generated and transmitted to the wireless power transmitter 2020.

The wireless power transmitter 2010 may ignore the received first response packet (S2005). That is, the wireless power transmitter 2010 may continue to perform wireless charging in the first charging mode even when the wireless power transmitter 2010 receives a predetermined first response packet requesting the second charging mode. In addition, the wireless power transmitter 2010 may use the charging mode restriction state information stored in the storage unit 470 to perform the step S2005. In addition, the wireless power transmitter 2010 may use the charging mode restriction state information stored in the storage unit 470 and the reconnection time to perform the step S2005.

FIG. 21 is a diagram for describing an embodiment of a first charging mode change of FIG. 18 in a wireless power transmitter.

An operation (S1803) of performing the first charge mode change of FIG. 18 will be described in more detail with reference to FIG. 21.

The first change of the charging mode of S1803 may be performed when the wireless power transmitter determines that the charging mode is restricted while operating in the second charging mode (S2101).

The wireless power transmitter may stop power transmission (S2102). That is, the wireless power transmitter may stop the charging power transmission while the wireless power transmitter is charging wirelessly even if the wireless power receiver does not request to stop the power transmission.

The wireless power transmitter may reconnect with the wireless power receiver (S2103). That is, the wireless power transmitter may reconnect with the wireless power receiver to perform wireless charging after stopping power transmission. The reconnection may proceed in the order of selection, ping, identification and configuration, and power transmission according to the first wireless power transmission procedure.

When the packet for initial power control is received from the wireless power receiver after the transition to the power transmission step, the wireless power transmitter may generate a predetermined first packet indicating that the second charging mode is supported and transmit the generated first packet to the wireless power receiver (S2104 to S). S2105).

The wireless power transmitter may receive a first response packet requesting a second charging mode (S2106).

The wireless power transmitter may determine whether the reconnection time is within a threshold reconnection time (S2107). Accordingly, the wireless power transmitter may increase the accuracy of the charging mode restriction state determination. This is because the reconnection time of the wireless power transmitter may exceed the threshold reconnection time if the user reconnects after stopping the charging arbitrarily. The threshold reconnection time may be a preset time.

If the reconnection time is within the threshold reconnection time, the wireless power transmitter may ignore the first response packet requesting the second charging mode and continue charging in the first charging mode (S2108 to S2109). The wireless power transmitter ignoring the first response packet may mean that the wireless power transmitter does not perform charging in the second charging mode until the charging mode restriction state ends. In addition, the wireless power transmitter may continuously perform wireless charging in the first charging mode without entering the second charging mode based on the charging mode restriction state information and the reconnection time stored in the storage unit 470 before the power transmission stops. . More specifically, the wireless power transmitter may receive the first response packet requesting the second charging mode if the charging mode is restricted before the power transmission stops and the reconnection time is within the threshold reconnection time, but may continue charging in the first charging mode. . S2109 may be S1804 of FIG. 18.

If the reconnection time exceeds the threshold reconnection time, the wireless power transmitter may initialize the charging mode restriction state information and perform charging in the second charging mode (S2110 to S2111). More specifically, the wireless power transmitter may initialize the charging mode restriction state information stored in the storage unit 470 when the reconnection time exceeds the threshold reconnection time. For example, the initialization of the charging mode restriction state information may be to change the value to not the charging mode restriction state before reconnection. In this case, the wireless power transmitter may perform the wireless charging by changing the charging mode from the first charging mode to the second charging mode according to the received first response packet.

The first change of the charging mode ends by entering the step S1804 of FIG. 18 by performing charging in the first charging mode ignoring the first response packet, or ending by performing charging in the second charging mode according to the first response packet. It may be (S2112).

FIG. 22 is a diagram for describing an exemplary embodiment of determining a charge mode restriction release state of FIG. 18.

An operation (S1805) of determining the charge mode restriction release state of FIG. 18 will be described in more detail with reference to FIG. 22.

Determination of the charge mode restriction release state may be performed in a step in which the wireless power transmitter performs charging in the first charging mode after changing the charging mode first (S2201).

The wireless power transmitter may sense a driving current (S2202). More specifically, as illustrated in FIGS. 4 and 5, the sensing current 500 of the sensing unit 450 may sense the driving current applied to the driving unit 4210.

In operation S2203, it may be determined whether the sensed driving current is in a second state equal to or greater than a second threshold current. The second state may be a state in which the value of the sensed driving current is greater than or equal to the value of the second threshold current. The second threshold current may be a criterion indicating that the wireless power transmitter is in a state capable of providing high power to the wireless power receiver. The second threshold current may be a value obtained by increasing the driving current value according to a request for increasing the charging power of the wireless power receiver. In addition, the second threshold current may be a preset current value. In addition, the second threshold current may be greater than or equal to 390 mA and less than or equal to 450 mA. More specifically, the second threshold current may be 420 mA.

The wireless power transmitter may determine the second state and determine whether the second state is maintained for a second time (S2204). That is, the wireless power transmitter may determine whether the state where the value of the driving current is greater than or equal to the value of the second threshold current is maintained for the second time. Accordingly, the wireless power transmitter may prevent an error that the second state occurs for a while to determine that the charging mode restriction release state is not even when the charging mode restriction release state is not present. The second time may be a preset time. In addition, the second time may be 1 second or more and 10 seconds or less. More specifically, the second time may be 5 seconds.

When the second state is maintained for the second time, the wireless power transmitter may determine that the charging mode is restricted (S2205). The wireless power transmitter is not limited thereto and may determine that the wireless power transmitter is in the charge mode restriction release state if the second state is present. This case is a case where the procedure proceeds from S2203 to S2205.

If it is not the second state or the second state is not maintained for a second time, the wireless power transmitter may determine that the charging mode is not in the restricted mode release state (S2206).

The wireless power transmitter may perform the second change of the charging mode when it determines that the charging mode is restricted. If it is determined that the wireless power transmitter is not in the state of canceling the charging mode, the wireless power transmitter may continue to charge in the first charging mode (S2207).

FIG. 23 is a diagram for describing an exemplary embodiment of a second change of the charging mode of FIG. 18 on a wireless charging system.

Referring to FIG. 23, while performing charging in the first charging mode, the wireless power receiver 2320 may stop charging power control due to an event. In this case, the wireless power transmitter 2310 may be determined to be in a charge mode restriction release state (S2301).

The wireless power transmitter may start charging in the second charging mode (S2302). Since the wireless power transmitter has already received the first response packet requesting the second charging mode in S2004 of FIG. 20 or S2106 of FIG. 21, the wireless power transmitter may perform wireless charging in the second charging mode. Also, although not shown, the wireless power transmitter may switch the charging mode after a predetermined charging mode change waiting time elapses when the wireless power transmitter switches from the first charging mode to the second charging mode. The charging mode change wait time may be predefined or determined by the wireless power receiver 2320 and then transmitted to the wireless power transmitter 2310 through a first response packet. The wireless power transmitter 2310 uses the control error packet of the wireless power receiver 2320 according to the state of the wireless power receiver 2320 to satisfy the guaranteed power set in the power transmission contract according to the second charging mode. The charging power transmitted from the 2310 may be controlled (S2303).

FIG. 24 is a graph illustrating a change in charge rate of a battery that is a load and a change in driving current of a wireless power transmitter according to a heat generation phenomenon during charging in a second charging mode in the wireless power transmitter of FIG. 18.

Referring to FIG. 24, when it is determined that the battery temperature a is a predetermined reference value, the wireless power receiver may control the charging power transmitted from the wireless power transmitter. In this case, the wireless power transmitter may reduce the driving current c to reduce the transmission power according to the charging power control of the wireless power receiver. For example, as shown in FIG. 24, the temperature of the battery in operation of the load during charging in the second wireless charging mode (for example, display on if the load is a mobile phone, application operation of the load in another example) May increase and the battery temperature a may reach a reference value at a first time point, that is, about 5 seconds. In this case, the wireless power receiver may transmit a control error packet reducing the transmission power to lower the battery temperature from the first time point. The wireless power transmitter receives the control error packet at the first time point to reduce the drive current c.

The wireless power transmitter according to another exemplary embodiment of FIG. 18 may determine that the charging mode is restricted based on the driving current c and perform the first change of the charging mode. For example, as shown in FIG. 24, the wireless power transmitter may perform the wireless charging by changing the charging mode from the second charging mode to the first charging mode when the driving current c is less than or equal to 320 mA, which is the first threshold current. have. In this case, on the basis of the first change time of the charging mode, it may be confirmed that the temperature increase rate of the battery is reduced to suppress the heat generation, and at the same time, the charging rate of the battery is increased. That is, in FIG. 17, when the wireless power transmitter according to the exemplary embodiment is used, the heat generation phenomenon is suppressed by operating in the second charging mode even in the limited charging mode, but the charging rate is reduced.

FIG. 25 is a graph illustrating a charging rate with time to explain the graph of FIG. 24.

Referring to FIG. 25, when there is no limitation of the charging mode by the wireless power receiver, the battery is charged at the charging speed of the first-first slope A-1 when charging in the second charging mode, and at the first time point t1. Charging can be completed. In addition, when the battery is charged in the first charging mode, the battery may be charged at the charging speed of the second inclination B-1 and the charging may be completed at the second time t2. When the charging mode is restricted by the wireless power receiver due to the heat generation phenomenon, the battery performs charging in the 1-2th slope A-2 when charging in the second charging mode. When charging is performed in the first charging mode, the battery is charged at the second-2 slope B-2. At this time, in the charging mode restriction state, the charging speed (see A-2) of the second charging mode is slower than the charging speed (see B-2) of the first charging mode. This is because, as described above, the request for reducing the charging power of the wireless power receiver to suppress the heat generation in the second charging mode is larger than the first charging mode.

Accordingly, when the wireless power transmitter according to another embodiment performs charging with the first-first tilt A-1 in the second charging mode and reaches the limited charging mode, the wireless power transmitter may tilt the second-2 with the first charging mode B. Charging can be performed at -2) to increase the charging speed. As a result, when charging is performed in the second charging mode, charging is completed at the fourth time point t4. However, according to another embodiment, the charging mode is changed from the charging limit state to the first charging mode while charging to the second charging mode. The charging may be completed at the third time point t3. That is, the charging speed may be increased by the time equal to the fourth time point t4 to the third time point t3.

FIG. 26 is a graph illustrating a change in charge rate of a battery that is a load and a change in driving current of the wireless power transmitter as the wireless power transmitter of FIG. 18 approaches the charging completion state during charging in the second charging mode.

Referring to FIG. 26, if it is determined that the charging rate b of the battery is a predetermined reference value, the wireless power receiver may control the charging power transmitted from the wireless power transmitter. In this case, the wireless power transmitter may reduce the driving current c to reduce the transmission power according to the charging power control of the wireless power receiver. For example, as shown in FIG. 26, the charging completion state step (about 95% charge rate) of the battery may be reached at a specific time during charging in the second wireless charging mode. In this case, the wireless power receiver may transmit a control error packet that reduces the transmission power to protect the battery from the specific time point. The wireless power transmitter receives the control error packet at a certain point in time to reduce the drive current c.

The wireless power transmitter according to another exemplary embodiment of FIG. 18 may determine that the charging mode is restricted based on the driving current c and perform the first change of the charging mode. For example, as shown in FIG. 26, the wireless power transmitter may perform the wireless charging by changing the charging mode from the second charging mode to the first charging mode when the driving current c is less than or equal to 320 mA, which is the first threshold current. have. In this case, it may be confirmed that the charging speed of the battery is increased based on the first change time of the charging mode.

27 is a view for explaining another embodiment of determining the charging mode restriction state of FIG. 18.

A step S1802 of determining the charging mode restriction state of FIG. 18 will be described in more detail with reference to FIG. 27.

The charging mode restriction state determination may be performed in the step of the wireless power transmitter performing charging in the second charging mode (S2701).

The wireless power transmitter may sense an operating frequency (S1902). More specifically, as shown in FIG. 4, an operating frequency sensor of the sensing unit 450 may sense an operating frequency of AC power provided to the transmitting coil 422.

The wireless power transmitter may determine whether the sensed operating frequency is the third state that is equal to or greater than the first threshold frequency (S2703). The third state may be a state in which the value of the sensed operating frequency is greater than or equal to the value of the first threshold frequency. The first threshold frequency may be an operating frequency value at which the charging rate of the battery begins to decrease even while wireless charging is in progress. More specifically, the first threshold frequency may be an operating frequency value when the charging rate of the battery begins to decrease due to an operation of consuming high power of the load while performing charging in the second charging mode. In addition, the first threshold frequency may be a preset frequency value.

The wireless power transmitter may determine the third state and determine whether the third state is maintained for a third time (S2704). That is, the wireless power transmitter may determine whether the state where the value of the operating frequency is greater than or equal to the value of the first threshold frequency is maintained for the third time. Accordingly, the wireless power transmitter may prevent an error of determining that the charging mode is restricted even though the third state occurs for a while and not in the limited charging mode. The third time may be a time at which the charging rate of the battery is reduced by maintaining a third state in which the sensed operating frequency is greater than or equal to the first threshold frequency and consuming high power of the load while performing charging in the second charging mode. In addition, the third time may be a preset time. In addition, the third time may be 1 second or more and 10 seconds or less. More specifically, the third time may be 5 seconds.

If the third state is maintained for a third time, the wireless power transmitter may determine that the charging mode is restricted (S2705). The wireless power transmitter is not limited thereto and may determine that the wireless power transmitter is in the charging mode limited state. In this case, the process proceeds from S2703 to S2705.

If it is not the third state or the third state is not maintained for the third time, the wireless power transmitter may determine that the charging mode is not in the limited state (S2706).

If the wireless power transmitter determines that the charging mode is restricted, the wireless power transmitter may store the current charging mode limited state in the storage unit 470. In this case, the wireless power transmitter may check the stored charging mode restriction state to perform the first charging mode change of S1803. In addition, if it is determined that the wireless power transmitter is not in the limited charging mode, the wireless power transmitter may perform charging in the second charging mode of S1803 (S2707).

28 is a view for explaining another embodiment of determining the charge mode restriction release state of FIG. 18 when the determination of the charge mode restriction state according to FIG. 27 is performed.

A step S1805 of determining the charge mode restriction release state of FIG. 18 will be described in more detail with reference to FIG. 28.

Determination of the charge mode restriction release state may be performed in a step in which the wireless power transmitter performs charging in the first charging mode after changing the charging mode first (S2801).

The wireless power transmitter may sense an operating frequency (S2802). More specifically, as shown in FIG. 4, an operating frequency sensor of the sensing unit 450 may sense an operating frequency of AC power provided to the transmitting coil 422.

The wireless power transmitter may determine whether the sensed operating frequency is a fourth state that is less than or equal to the second threshold frequency (S2803). The fourth state may be a state in which the value of the sensed operating frequency is less than or equal to the value of the second threshold frequency. The second threshold frequency may be a criterion indicating that the wireless power transmitter is in a state capable of providing high power to the wireless power receiver. The second threshold frequency may be a value at which the operating frequency is lowered and reached according to a request for increasing the charging power of the wireless power receiver. In addition, the second threshold frequency may be a preset frequency value.

The wireless power transmitter determines that the fourth state is determined and determines whether the fourth state is maintained for a fourth time (S2804). That is, the wireless power transmitter may determine whether the state where the value of the operating frequency is greater than or equal to the value of the second threshold frequency is maintained for the fourth time. Accordingly, the wireless power transmitter may prevent an error that the fourth state occurs for a while and determines that the charging mode restriction release state is not performed even if the fourth state does not occur. The fourth time may be a preset time. In addition, the fourth time may be 1 second or more and 10 seconds or less. More specifically, the fourth time may be 5 seconds.

If the fourth state is maintained for the fourth time, the wireless power transmitter may determine that the charging mode is restricted (S2805). The wireless power transmitter is not limited thereto, and may determine that the wireless power transmitter is in the charge mode restriction release state if the fourth state. In this case, the process proceeds from S2803 to S2805.

If it is not the fourth state or if the fourth state is not maintained for the fourth time, the wireless power transmitter may determine that the charging mode is not in the restricted mode release state (S2806).

If it is determined that the wireless power transmitter is in the charge mode restriction release state, the wireless power transmitter may perform the second change of the charging mode. If the wireless power transmitter determines that it is not in the charge mode restriction release state, the wireless power transmitter may continue to charge in the first charge mode (S2807).

FIG. 29 is a diagram for describing another embodiment of determining the charging mode restriction state of FIG. 18.

A step S1802 of determining the charging mode restriction state of FIG. 18 will be described in more detail with reference to FIG. 29.

The charging mode restriction state determination may be performed in the step of the wireless power transmitter performing charging in the second charging mode (S2901).

The wireless power transmitter may sense an operating frequency (S2902). More specifically, as shown in FIG. 4, an operating frequency sensor of the sensing unit 450 may sense an operating frequency of AC power provided to the transmitting coil 422.

The wireless power transmitter may determine whether the sensed operating frequency is greater than or equal to the third threshold frequency (S2903). The second threshold frequency may be a preset frequency value. In addition, the third threshold frequency may be the same as the first threshold frequency.

If the operating frequency is greater than or equal to the third threshold frequency, the wireless power transmitter may sense an operating duty ratio (S2904). More specifically, as shown in FIG. 4, an operation duty ratio sensor of the sensing unit 450 may sense an operation duty ratio of AC power provided to the transmission coil 422. In particular, operating duty ratio sensing may be performed simultaneously with operating frequency sensing.

The wireless power transmitter may determine whether the sensed operating duty ratio is a fifth state that is less than or equal to the first threshold duty ratio (S2905). The fifth state may be a state in which the value of the sensed operation duty ratio is less than or equal to the value of the first threshold duty ratio. The first threshold duty ratio may be an operation duty ratio value at which the charging rate of the battery starts to decrease even while wireless charging is in progress. More specifically, the first threshold duty ratio may be an operation duty ratio value when the charging rate of the battery starts to decrease due to an operation of consuming high power of the load while performing charging in the second charging mode. In addition, the first threshold duty ratio may be a preset frequency value.

The wireless power transmitter may determine whether the fifth state is maintained for a fifth time (S2906). That is, the wireless power transmitter may determine whether the state where the value of the operating frequency is greater than or equal to the value of the third threshold frequency and the value of the operating duty ratio is less than or equal to the value of the first threshold duty ratio is maintained for the fifth time. Accordingly, the wireless power transmitter may prevent an error of determining that the charging mode is restricted even though the fifth state occurs for a while and is not the charging mode limited state. The fifth time is an operation in which a fifth state in which the sensed operating frequency is greater than or equal to the third threshold frequency and the sensing operation duty ratio is less than or equal to the first threshold duty ratio is maintained to consume high power of the load while charging in the second charging mode. It may be time that the charging rate of is reduced. In addition, the fifth time may be a preset time. In addition, the fifth time may be 1 second or more and 10 seconds or less. More specifically, the fifth time may be 5 seconds.

When the fifth state is maintained for the fifth time, the wireless power transmitter may determine that the charging mode is restricted (S2907). The wireless power transmitter is not limited thereto and may determine that the wireless power transmitter is in the charging mode limited state. In this case, the process proceeds from S2905 to S2907.

In operation S2908, the wireless power transmitter determines that the operating frequency value is less than the third threshold frequency, is not the fifth state, or the fifth state is not maintained for the fifth time (S2908).

If the wireless power transmitter determines that the charging mode is restricted, the wireless power transmitter may store the current charging mode limited state in the storage unit 470. In this case, the wireless power transmitter may check the stored charging mode restriction state to perform the first charging mode change of S1803. In addition, if it is determined that the wireless power transmitter is not in the limited charging mode, the wireless power transmitter may perform charging in the second charging mode of S1803 (S2909).

30 is a view for explaining another embodiment of determining the charge mode restriction release state of FIG. 18 when the determination of the charge mode restriction state according to FIG. 29 is performed.

A step S1805 of determining the charge mode restriction release state of FIG. 18 will be described in more detail with reference to FIG. 30.

Determination of the charge mode restriction release state may be performed in a step in which the wireless power transmitter performs charging in the first charging mode after changing the charging mode first (S3001).

The wireless power transmitter may sense an operating frequency (S3002). More specifically, as shown in FIG. 4, an operating frequency sensor of the sensing unit 450 may sense an operating frequency of AC power provided to the transmitting coil 422.

The wireless power transmitter may determine whether the sensed operating frequency is a sixth state that is equal to or less than a fourth threshold frequency (S3003). The sixth state may be a state in which a value of the sensed operating frequency is equal to or less than a value of the fourth threshold frequency. The fourth threshold frequency may be a criterion indicating that the wireless power transmitter is in a state capable of providing high power to the wireless power receiver. The fourth threshold frequency may be a value at which the operating frequency is lowered and reached according to a request for increasing the charging power of the wireless power receiver. The value of the fourth threshold frequency may be smaller than the value of the third threshold frequency. In addition, the fourth threshold frequency may be a preset frequency value.

The wireless power transmitter determines that the sixth state is determined and determines whether the sixth state is maintained for the sixth time (S2804). That is, the wireless power transmitter may determine whether the state where the value of the operating frequency is less than or equal to the fourth threshold frequency is maintained for the sixth time. Accordingly, the wireless power transmitter may prevent an error in which the sixth state occurs for a while and determines that the charging mode restriction release state is not performed even if the sixth state occurs. The sixth time may be a preset time. In addition, the sixth time may be 1 second or more and 10 seconds or less. More specifically, the sixth time may be 5 seconds.

When the sixth state is maintained for the sixth time, the wireless power transmitter may determine that the charging mode is restricted (S3008). The wireless power transmitter is not limited thereto and may determine that the wireless power transmitter is in the charge mode restriction release state in the sixth state. In this case, the process proceeds from S3003 to S3008.

If it is determined that the state is not the sixth state, the wireless power transmitter may sense an operation duty ratio in operation S3005. More specifically, as shown in FIG. 4, an operation duty ratio sensor of the sensing unit 450 may sense an operation duty ratio of AC power provided to the transmission coil 422. In particular, operating duty ratio sensing may be performed simultaneously with operating frequency sensing.

The wireless power transmitter may determine whether the sensed operating duty ratio is a seventh state that is greater than or equal to the second threshold duty ratio (S3006). The seventh state may be a state in which the value of the sensed operating frequency exceeds the fourth threshold frequency and the value of the sensed operating duty ratio is greater than or equal to the second threshold duty ratio value. The second threshold duty ratio may be a criterion indicating that the wireless power transmitter is in a state capable of providing high power to the wireless power receiver. The second threshold duty ratio may be a value obtained by increasing the operation duty ratio value according to a request for increasing the charging power of the wireless power receiver. The value of the second threshold duty ratio may be greater than the value of the first threshold duty ratio. In addition, the second threshold duty ratio may be a preset frequency value.

The wireless power transmitter may determine the seventh state and determine whether the seventh state is maintained for the seventh time (S3007). That is, the wireless power transmitter may determine whether the state where the value of the operation duty ratio is greater than or equal to the value of the second threshold duty ratio is maintained for the seventh time. Accordingly, the wireless power transmitter may prevent an error that the seventh state occurs for a while and determines that the charging mode restriction release state is not performed even when the charging mode restriction release state is not generated. The seventh time may be a preset time. In addition, the seventh time may be equal to the sixth time. In addition, the seventh time may be 1 second or more and 10 seconds or less. More specifically, the seventh time may be 5 seconds.

If the seventh state is maintained for the seventh time, the wireless power transmitter may determine that the charging mode is restricted (S3008). The wireless power transmitter is not limited thereto and may determine that the wireless power transmitter is in the charge mode restriction release state when the seventh state is present. In this case, the process proceeds in the order of S3005 to S3008.

If the sixth state is not maintained for the sixth time or is not the seventh state or the seventh state is not maintained for the seventh time, the wireless power transmitter may determine that the wireless power transmitter is not in the state of canceling the charging mode (S3009).

If it is determined that the wireless power transmitter determines that the charging mode is not in the restricted mode, the wireless power transmitter may perform the second charging mode change. If it is determined that the wireless power transmitter is not in the restricted mode, the wireless power transmitter may continue to perform charging in the first charging mode (S3010).

31 is a view for explaining another embodiment of the first change of the charging mode of FIG. 18 on the wireless charging system.

Referring to FIG. 31, if the wireless power transmitter 3110 determines that the charging mode is restricted while the charging is performed in the second charging mode, the wireless power transmitter 3110 may stop power transmission (S3101). Thereafter, the wireless power transmitter 3110 may proceed with the first wireless power transmission procedure in order of selection, ping, identification and configuration, and power transmission. As an example, the reconnection time may be a time until the signal strength packet is received by the wireless power receiver 3120 after the power transmission stops. As another example, the reconnection time may be a time until the reception of the identification packet of the wireless power receiver 3120 after the power transmission stops. As another example, the first reconnection time may be a time until the reception of the configuration packet of the wireless power receiver 3120 after the power transmission stops.

The wireless power transmitter 3110 may transmit a predetermined first packet indicating the second charging mode support after the first control error packet is received from the wireless power receiver 3120 after the transition to the power transmission step in the identification and configuration phase. 3120 may not be transmitted (S3102 to S3103). That is, the wireless power transmitter 3110 may continue to perform wireless charging in the first charging mode without transmitting the first packet informing of the second charging mode support. In addition, the wireless power transmitter 3110 may use the charging mode restriction state information stored in the storage unit 470 to perform step S3103. In addition, the wireless power transmitter 3110 may use the charging mode restriction state information stored in the storage unit 470 and the reconnection time to perform the step S3103.

32 is a view for explaining another embodiment of the first change of the charging mode of FIG. 18 in the wireless power transmitter.

Referring to FIG. 32, an operation S1803 of performing the charging mode first change of FIG. 18 will be described in more detail according to another exemplary embodiment.

The first change of the charging mode of S1803 may be performed when the wireless power transmitter determines that the charging mode is restricted while operating in the second charging mode (S3201).

The wireless power transmitter may stop power transmission (S3202). That is, the wireless power transmitter may stop the charging power transmission while the wireless power transmitter is charging wirelessly even if the wireless power receiver does not request to stop the power transmission.

The wireless power transmitter may reconnect with the wireless power receiver (S3203). That is, the wireless power transmitter may reconnect with the wireless power receiver to perform wireless charging after stopping power transmission. The reconnection may proceed in the order of selection, ping, identification and configuration, and power transmission according to the first wireless power transmission procedure.

The wireless power transmitter may receive a packet for initial power control from the wireless power receiver after the transition to the power transmission step (S2304).

The wireless power transmitter may determine whether the reconnection time is within the threshold reconnection time (S3205). Accordingly, the wireless power transmitter may increase the accuracy of the charging mode restriction state determination. This is because the reconnection time of the wireless power transmitter may exceed the threshold reconnection time if the user reconnects after stopping the charging arbitrarily. The threshold reconnection time may be a preset time.

If the reconnection time is within the threshold reconnection time, the wireless power transmitter may continue to charge in the first charging mode without transmitting the first packet indicating the second charging mode support (S3206 to S3207). When the wireless power transmitter receives the packet for the first power control but does not transmit the first packet indicating the second charging mode support, it means that the wireless power transmitter does not perform charging in the second charging mode until the charging mode restriction state ends. Can be. In addition, the wireless power transmitter may continuously perform wireless charging in the first charging mode without entering the second charging mode based on the charging mode restriction state information and the reconnection time stored in the storage unit 470 before the power transmission stops. . More specifically, the wireless power transmitter may continue charging in the first charging mode without charging in the second charging mode when the charging mode is restricted before the power transmission stops and the reconnection time is within the threshold reconnection time. S3209 may be S1804 of FIG. 18.

If the reconnection time exceeds the threshold reconnection time, the wireless power transmitter may initialize the charging mode restriction state information (S3208). More specifically, the wireless power transmitter may initialize the charging mode restriction state information stored in the storage unit 470 when the reconnection time exceeds the threshold reconnection time. For example, the initialization of the charging mode restriction state information may be to change the value to not the charging mode restriction state before reconnection. After initialization of the charging mode restriction state information, a predetermined first packet indicating that the second charging mode is supported may be generated and transmitted to the wireless power receiver (S3209). That is, the wireless power transmitter may transmit the first packet indicating that the second charging mode is supported in response to the packet reception for the initial power control.

The wireless power transmitter may receive a first response packet requesting the second charging mode from the wireless power receiver and perform charging in the second charging mode (S3210 to S3211).

The charging mode first change ends by entering charging step S1804 of FIG. 18 by performing charging in the first charging mode without transmitting the first packet, or by transmitting the first packet and receiving the first response packet. The operation may be terminated by performing charging in the charging mode (S3212).

33 is a view for explaining another embodiment of the second change of the charging mode of FIG. 18 on the wireless charging system.

Referring to FIG. 33, while performing charging in the first charging mode, the wireless power receiver 3320 may stop charging power control due to an event. In this case, the wireless power transmitter 310 may determine that the charging mode is restricted (S3301).

The wireless power transmitter 3310 may generate a predetermined first packet indicating the second charging mode support and transmit the generated first packet to the wireless power receiver 3320 (S3302). Since the wireless power transmitter has received the packet for initial power control in S3102 of FIG. 31 or S3204 of FIG. 32, the wireless power transmitter may transmit a predetermined first packet indicating the second charging mode support.

When the wireless power receiver 3320 determines that the wireless power transmitter 310 supports the second charging mode based on the received first packet, and the device is capable of charging in the second charging mode, the wireless power receiver 3320 may charge the second power. A predetermined first response packet requesting a mode may be generated and transmitted to the wireless power transmitter 3310 (S3303).

The wireless power transmitter may start charging in the second charging mode (S3302). Also, although not shown, the charging mode may be switched after a predetermined charging mode change waiting time elapses when the first charging mode is switched from the second charging mode. The charging mode change wait time may be predefined or determined by the wireless power receiver 3320 and then transmitted to the wireless power transmitter 3310 through the first response packet. The wireless power transmitter 3310 uses the control error packet of the wireless power receiver 3320 to satisfy the guaranteed power set in the power transmission contract according to the second charging mode or according to the state of the wireless power receiver 3320. The charging power transmitted from the 3310 may be controlled (S3305).

34 is a view for explaining another embodiment of the second charging mode change of FIG. 18 in the wireless power transmitter.

The second change of the charging mode of S1806 may be performed when the wireless power transmitter determines that the charging mode is restricted while in the first charging mode (S3401).

The wireless power transmitter may generate a predetermined first packet indicating that the second charging mode is supported and transmit the generated first packet to the wireless power receiver (S3409). That is, the wireless power transmitter may transmit the first packet indicating that the second charging mode is supported in response to the packet reception for the initial power control.

The wireless power transmitter may receive a first response packet requesting the second charging mode from the wireless power receiver and perform charging in the second charging mode (S3403 to S3404).

The wireless power transmitter may terminate the second change of the charging mode by performing charging in the second charging mode as the first packet is transmitted and the first response packet is received (S3405).

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

Referring to FIG. 35, in the power transmission step, the wireless power transmitter may perform charging with the first guaranteed power (S3601). The guaranteed power 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 by a power transmission contract. More specifically, the guaranteed power may include a first guaranteed power having a relatively large guaranteed power value and a second guaranteed power having a relatively small guaranteed power value.

The wireless power transmitter may determine whether the wireless power transmitter is in the guaranteed power limit state while charging with the first guaranteed power (S3502). The guaranteed power limit state may be a state limited to perform charging with a specific guaranteed power. More specifically, the guaranteed power limit state may be a state that should be controlled to perform charging with the second guaranteed power. In addition, the guaranteed power limited state may be a state in which the intensity of power transmitted from the second guaranteed power to the first guaranteed power is smaller according to the charging power control due to the event of the wireless power receiver. For example, the event may be a heat generation phenomenon such as a sudden temperature rise or a high temperature state of a wireless power receiver or a load, for example, a battery. In addition, as another example of the event, the state of charge of the battery may be close to full charge. In addition, the method of determining the guaranteed power limit state may be the same as the method of determining the charge mode limit state of FIGS. 19, 27, and 29.

If it is determined that the guaranteed power limit state, the wireless power transmitter may perform the first change of the power transmission contract that changes from the first guaranteed power to the second guaranteed power (S3503). The strength of the first guaranteed power in the power transmission contract is greater than the strength of the second guaranteed power. However, in the guaranteed power limited state, due to the changed charging power control according to the guaranteed power strength of the power transmission contract of the wireless power receiver, the actual guaranteed power is smaller at the first guaranteed power than at the second guaranteed power. The charging speed of the battery may be increased by controlling to perform charging with power. Therefore, the wireless power transmitter according to another embodiment may improve the heat generation phenomenon of the wireless power receiver and at the same time increase the charging speed. In addition, in the same principle, the wireless power transmitter according to another embodiment may increase the charging speed while protecting the battery in a fully charged state of the battery. If it is determined that the guaranteed power is not in a limited power state, the wireless power transmitter may perform charging with the first guaranteed power of S3501.

The first modification of the power transmission contract will be described in detail. The first modification to the power transfer agreement may include the wireless power transmitter stopping the power transfer. The first modification to the power transfer agreement may include reconnecting the wireless power transmitter with the wireless power receiver after the power transfer stops. Reconnection may proceed in the order of selection, ping, identification and configuration, and negotiation according to the second wireless power transfer procedure. The first modification to the power transfer agreement may include determining whether the reconnection time of the wireless power transmitter is within a threshold reconnection time. Accordingly, the wireless power transmitter may increase the accuracy of the guaranteed power limitation state determination. This is because the reconnection time of the wireless power transmitter may exceed the threshold reconnection time if the user reconnects after stopping the charging arbitrarily. The threshold reconnection time may be a preset time. The first modification to the power transfer agreement may include receiving, from the wireless power receiver, a general request packet requesting a power transmitter capability packet for the power transfer agreement after the wireless power transmitter transitions to the negotiation phase. The first modification to the power transfer agreement may include sending, by the wireless power transmitter, a power transmitter capability packet to the wireless power receiver that includes the second guaranteed power value in response to the general request packet if the reconnection time is within the threshold reconnection time. Can be. That is, the wireless power transmitter may provide a relatively high potential power value as the guaranteed power of the power transmitter capability packet based on the supply power provided by the power supply unit 460, but may be lower than the potential power value because it is a guaranteed power limited state. To provide a second guaranteed power value as a guaranteed power value of a transmitter capability packet. The first change in power transmission contract may include receiving, by the wireless power transmitter, a special request packet from the wireless power receiver for proposing a guaranteed power value of the power transmission contract based on the second guaranteed power value of the power transmitter capability packet. Can be. The first modification to the power transfer agreement may include the wireless power transmitter sending an ACK packet to the wireless power receiver in response to a special request packet for proposing a guaranteed power value of the power transfer agreement. That is, the wireless power transmitter has accepted the guaranteed power value of the power transmission contract proposed by the wireless power receiver. The first modification to the power transfer agreement may then include the wireless power transmitter receiving a special request packet from the wireless power receiver to complete the power transfer agreement to end the negotiation phase. That is, the wireless power transmitter transmits an ACK packet with acceptance of the end of the negotiation step. As a result, the guaranteed power of the power transmission contract between the wireless power transmitter and the wireless power receiver becomes the second guaranteed power. For example, the wireless power transmitter may provide charging power at 15W, which is a potential power, but since the guaranteed power is limited, the power transmission contract may be performed at 5W, which is the guaranteed power value. The first modification to the power transfer contract may cause the wireless power transmitter to send the power transmitter capability packet to the wireless power receiver with the potential power value as the guaranteed power value in response to the general request packet if the reconnection time exceeds the threshold reconnection time. have.

After the first change of the power transmission contract, the wireless power transmitter may perform charging with the second guaranteed power (S3504).

While charging with the second guaranteed power, the wireless power transmitter may determine whether the guaranteed power limit is released (S3505). The method of determining the guaranteed power limit state may be the same as the method of determining the charge mode limit release state of FIGS. 22, 28, and 30.

If it is determined that the guaranteed power limit is released, the wireless power transmitter may perform a second change of the power transmission contract that changes from the second guaranteed power to the first guaranteed power (S3506). That is, the wireless power transmitter according to another embodiment may enable the charging with the first guaranteed power to increase the charging speed when the guaranteed power limit is released and the charging power control due to the event in the wireless power receiver is stopped. . Therefore, the wireless power transmitter according to another embodiment may increase the charging speed by adaptively changing the guaranteed power according to the state of the wireless power receiver. If it is determined that the guaranteed power limit is not released, the wireless power transmitter may perform charging with the second guaranteed power of S3504.

The second modification of the power transmission contract will be described in detail. The second change in the power transfer agreement may include the wireless power transmitter stopping the power transfer. The second modification to the power transfer agreement may include reconnecting the wireless power transmitter with the wireless power receiver after the power transfer ceases. Reconnection may proceed in the order of selection, ping, identification and configuration, and negotiation according to the second wireless power transfer procedure. The second modification to the power transfer agreement may include receiving, from the wireless power receiver, a general request packet requesting a power transmitter capability packet for the power transfer agreement after the wireless power transmitter transitions to the negotiation phase. The second modification to the power transfer agreement may include the wireless power transmitter sending a power transmitter capability packet including the first guaranteed power value to the wireless power receiver in response to the general request packet. The first guaranteed power value may be higher than the second guaranteed power value. Also, the first guaranteed power value may be a potential power value, but is not limited thereto. The second change in the power transmission contract may include receiving, by the wireless power transmitter, a special request packet from the wireless power receiver for proposing a guaranteed power value of the power transmission contract based on the first guaranteed power value of the power transmitter capability packet. Can be. The second change in the power transfer agreement may include the wireless power transmitter sending an ACK packet to the wireless power receiver in response to a special request packet for proposing a guaranteed power value of the power transfer agreement. That is, the wireless power transmitter has accepted the guaranteed power value of the power transmission contract proposed by the wireless power receiver. The second modification to the power transfer agreement may then include the wireless power transmitter receiving a special request packet from the wireless power receiver to complete the power transfer agreement to end the negotiation phase. That is, the wireless power transmitter transmits an ACK packet with acceptance of the end of the negotiation step. As a result, the guaranteed power of the power transmission contract between the wireless power transmitter and the wireless power receiver becomes the first guaranteed power.

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

Another embodiment according to FIG. 36 is a power transmission contract that changes from the first guaranteed power to the second guaranteed power in another embodiment according to FIG. 35, and the power that changes from the second guaranteed power to the first guaranteed power. There is a difference in the second change of the transmission contract. The following description focuses on the configuration having the above difference.

Referring to FIG. 36, in the power transmission step, the wireless power transmitter may perform charging with the first guaranteed power (S3601).

While charging with the first guaranteed power, the wireless power transmitter may determine whether the guaranteed power is limited (S3602). The method of determining the guaranteed power limit state may be the same as the method of determining the charge mode limit state of FIGS. 19, 27, and 29.

If it is determined that the guaranteed power limit state, the wireless power transmitter may perform a third change of the power transmission contract that changes from the first guaranteed power to the second guaranteed power (S3603). The strength of the first guaranteed power in the power transmission contract is greater than the strength of the second guaranteed power. However, in the guaranteed power limited state, due to the changed charging power control according to the guaranteed power strength of the power transmission contract of the wireless power receiver, the actual guaranteed power is smaller at the first guaranteed power than at the second guaranteed power. The charging speed of the battery may be increased by controlling to perform charging with power. Therefore, the wireless power transmitter according to another embodiment may improve the heat generation phenomenon of the wireless power receiver and at the same time increase the charging speed. In addition, in the same principle, the wireless power transmitter according to another embodiment may increase the charging speed while protecting the battery in a fully charged state of the battery. If it is determined that the guaranteed power is not in a limited power state, the wireless power transmitter may perform charging with the first guaranteed power of S3501.

The third modification of the power transmission contract will be described in detail. The third modification to the power transfer agreement may include the wireless power transmitter transitioning to a renegotiation stage. That is, when the wireless power transmitter receives the received power packet from the wireless power receiver, the wireless power transmitter may transmit a NAK packet to renegotiate the wireless power receiver. The received power packet may be a 24-bit received power packet. The third modification to the power transfer agreement may include the wireless power transmitter receiving a renegotiation packet from the wireless power receiver and renegotiating with the wireless power receiver. The third modification to the power transfer agreement may include the wireless power transmitter sending a power transmitter capability packet including the second guaranteed power value to the wireless power receiver in response to the general request packet. That is, the wireless power transmitter may provide a relatively high potential power value as the guaranteed power of the power transmitter capability packet based on the supply power provided by the power supply unit 460, but may be lower than the potential power value because it is a guaranteed power limited state. To provide a second guaranteed power value as a guaranteed power value of a transmitter capability packet. The third change in the power transfer agreement may include the wireless power transmitter receiving a special request packet from the wireless power receiver for proposing a guaranteed power value of the power transfer agreement based on the second guaranteed power value of the power transmitter capability packet. Can be. The third modification to the power transfer agreement may include the wireless power transmitter sending an ACK packet to the wireless power receiver in response to a special request packet for proposing a guaranteed power value of the power transfer agreement. That is, the wireless power transmitter has accepted the guaranteed power value of the power transmission contract proposed by the wireless power receiver. The third modification to the power transfer agreement may then include the wireless power transmitter receiving a special request packet from the wireless power receiver to complete the power negotiation and terminate the renegotiation phase. In other words, the wireless power transmitter transmits an ACK packet with acceptance of the end of the renegotiation phase. As a result, the guaranteed power of the power transmission contract between the wireless power transmitter and the wireless power receiver becomes the second guaranteed power. For example, the wireless power transmitter may provide charging power at 15W, which is a potential power, but since the guaranteed power is limited, the power transmission contract may be performed at 5W, which is the guaranteed power value. After the third change of the power transmission contract, the wireless power transmitter may perform charging with the second guaranteed power (S3604).

While charging with the second guaranteed power, the wireless power transmitter may determine whether the guaranteed power limit is released (S3605). The method of determining the guaranteed power limit state may be the same as the method of determining the charge mode limit release state of FIGS. 22, 28, and 30.

If it is determined that the guaranteed power limit release state, the wireless power transmitter may perform a fourth change of the power transmission contract that changes from the second guaranteed power to the first guaranteed power (S3606). That is, the wireless power transmitter according to another embodiment may enable the charging with the first guaranteed power to increase the charging speed when the guaranteed power limit is released and the charging power control due to the event in the wireless power receiver is stopped. . Therefore, the wireless power transmitter according to another embodiment may increase the charging speed by adaptively changing the guaranteed power according to the state of the wireless power receiver. If it is determined that the guaranteed power limit is not released, the wireless power transmitter may perform charging with the second guaranteed power of S3504.

The fourth modification of the power transmission contract will be described in detail. The fourth modification to the power transfer agreement may include the wireless power transmitter transitioning to a renegotiation stage. That is, when the wireless power transmitter receives the received power packet from the wireless power receiver, the wireless power transmitter may transmit a NAK packet to renegotiate the wireless power receiver. The received power packet may be a 24-bit received power packet. The fourth modification to the power transfer agreement may include the wireless power transmitter receiving a renegotiation packet from the wireless power receiver and renegotiating with the wireless power receiver. The fourth change in the power transfer agreement may include the wireless power transmitter sending a power transmitter capability packet including the first guaranteed power value to the wireless power receiver in response to the general request packet. The first guaranteed power value may be higher than the second guaranteed power value. Also, the first guaranteed power value may be a potential power value, but is not limited thereto. The fourth change in the power transfer agreement may include the wireless power transmitter receiving a special request packet from the wireless power receiver for proposing a guaranteed power value of the power transfer agreement based on the first guaranteed power value of the power transmitter capability packet. Can be. The fourth modification to the power transfer agreement may include the wireless power transmitter sending an ACK packet to the wireless power receiver in response to a special request packet for proposing a guaranteed power value of the power transfer agreement. That is, the wireless power transmitter has accepted the guaranteed power value of the power transmission contract proposed by the wireless power receiver. The fourth modification to the power transfer agreement may then include the wireless power transmitter receiving a special request packet from the wireless power receiver to complete the power negotiation and terminate the renegotiation phase. In other words, the wireless power transmitter transmits an ACK packet with acceptance of the end of the renegotiation phase. As a result, the guaranteed power of the power transmission contract between the wireless power transmitter and the wireless power receiver becomes the first guaranteed power.

A wireless charging method according to an embodiment of the present invention provides a wireless charging method of a wireless power transmitter for wirelessly transmitting power to a wireless power receiver, the method comprising: performing charging in a second charging mode; Determining whether the charging mode is restricted while performing charging in the second charging mode; A first charging mode changing step of changing from a second charging mode to a first charging mode when the charging mode is restricted; And performing charging in the first charging mode.

In addition, in the wireless charging method according to the embodiment, the charging mode restriction state may be a state in which the wireless power receiver reduces the strength of the charging power supplied by the wireless power transmitter due to an event of the wireless power receiver.

In addition, in the wireless charging method according to the embodiment, the first charging mode is a low power charging mode, the second charging mode is a high power charging mode, and the wireless power transmitter is in the first charging mode than the second charging mode when the charging mode is restricted. Higher charging power may be provided to the wireless power receiver.

In addition, the wireless charging method according to the embodiment comprises the steps of determining whether the charge mode limitation release state while performing charging in the first charging mode; And a charging mode second changing step of changing from the first charging mode to the second charging mode when the charging mode restriction release state is established.

In addition, in the wireless charging method according to the embodiment, the charge mode restriction release state may be a state in which the wireless power receiver stops controlling the charging power supplied by the wireless power transmitter due to an event.

In addition, in the wireless charging method according to the embodiment, the first charging mode is a low power charging mode, the second charging mode is a high power charging mode, and the wireless power transmitter is a second charging mode than the first charging mode when the charging mode restriction release state. May provide higher charging power to the wireless power receiver.

The wireless charging method according to the embodiment may include determining whether the charging mode is restricted while performing charging in the second charging mode, by sensing a driving current; Determining whether the sensed driving current value is in a first state equal to or less than a first threshold current value; And determining whether the first state is maintained for a first time.

In addition, the wireless charging method according to the embodiment of the first charging mode change step, power transmission stop step; Reconnecting with the wireless power receiver; Receiving a packet for initial power control after transitioning to a power transfer step; Transmitting a first packet to announce second charging mode support; Receiving a first response packet requesting a second charging mode; And ignoring the first response packet.

The wireless charging method according to the embodiment may further include determining whether a reconnection time after receiving the first response packet is within a critical reconnection time after receiving the first response packet, and if the reconnection time is within the threshold reconnection time. The charging may be performed in the first charging mode by ignoring the first response packet.

The wireless charging method according to the embodiment may initialize the charging mode restriction state information and perform charging in the second charging mode when the reconnection time exceeds the threshold reconnection time.

Also, the wireless charging method according to the embodiment may include determining whether the charge mode restriction release state comprises: sensing a driving current; Determining whether the sensed drive current value is in a second state equal to or greater than a second threshold current value; And determining whether the second state is maintained for a second time.

Also, the wireless charging method according to the embodiment may include determining whether the charging mode is restricted while performing charging in the second charging mode, by sensing an operating frequency; Determining whether the sensed operating frequency value is in a third state equal to or greater than a first threshold frequency value; And determining whether the third state is maintained for a third time.

Also, the wireless charging method according to the embodiment may include determining whether the charge mode restriction release state comprises: sensing an operating frequency; Determining whether the sensed operating frequency value is a fourth state less than or equal to a second threshold frequency value; And determining whether the fourth state is maintained for a fourth time.

Also, the wireless charging method according to the embodiment may include determining whether the charging mode is restricted while performing charging in the second charging mode, by sensing an operating frequency; Determining whether the sensed operating frequency value is greater than or equal to a third threshold frequency value; Sensing an operating duty ratio if the sensed operating frequency value is greater than or equal to a third threshold frequency value; Determining a fifth state in which the operation duty ratio is less than or equal to a first threshold duty ratio; And determining whether the fifth state is maintained for a fifth time.

Also, the wireless charging method according to the embodiment may include determining whether the charge mode restriction release state comprises: sensing an operation duty ratio if the charge state is not the fourth state; Determining whether the sensed operation duty ratio is a seventh state equal to or greater than a second threshold duty ratio; And determining whether the seventh state is maintained for a seventh time.

In addition, the wireless charging method according to the embodiment of the first charging mode change step, power transmission stop step; Reconnecting with the wireless power receiver; Receiving a packet for initial power control after transitioning to a power transfer step; And not transmitting the first packet indicating the second charging mode support.

The wireless charging method according to the embodiment may further include determining whether the recharging time is within a critical reconnection time after receiving the packet for the initial power control, and wherein the reconnection time is the critical reconnection time. If it is within the time, charging may be performed in the first charging mode without transmitting the first packet.

The wireless charging method according to the embodiment of the present invention may further include: recharging the charging mode restriction state information when the reconnection time exceeds the threshold reconnection time; A first packet transmission step of informing a second charging mode support when the charging mode restriction state information is initialized; And receiving a first response packet requesting a second charging mode when the first packet is transmitted. When receiving the first response packet, charging may be performed in the second charging mode.

In addition, the wireless charging method according to an embodiment of the present invention, the second change of the charging mode, the first packet transmission step of informing the second charging mode support; Receiving a first response packet requesting a second charging mode when transmitting the first packet; And performing charging in the second charging mode when receiving the first response packet.

A wireless charging method in accordance with an embodiment of the present invention provides a wireless charging method in a wireless power transmitter for wirelessly transmitting power to a wireless power receiver, comprising: performing charging with a first guaranteed power; Determining whether a guaranteed power limit state is being performed while charging with the first guaranteed power; Changing a first power transmission contract from a first guaranteed power to a second guaranteed power when the guaranteed power is limited; And performing charging at a second guaranteed power.

Also, in the wireless charging method according to the embodiment, the guaranteed power limit state may be a state in which the wireless power receiver reduces the strength of the charging power supplied by the wireless power transmitter due to an event of the wireless power receiver.

In addition, the wireless charging method according to the embodiment includes the step of determining whether the guaranteed power limit is released while performing the charging with the second guaranteed power; And changing a second power transmission contract from the second guaranteed power to the first guaranteed power when the guaranteed power limit is released.

In addition, in the wireless charging method according to the embodiment, the guaranteed power limit release state may be a state in which the wireless power receiver stops controlling the charging power supplied by the wireless power transmitter due to an event.

In addition, the wireless charging method according to the embodiment, the first power transmission contract change step, the power transmission stop step; Reconnecting with the wireless power receiver; Receiving a generic request packet requesting a power transmitter capability packet for a power transfer contract after transitioning to a negotiation step; And transmitting a power transmitter capability packet including a second guaranteed power value in response to the general request packet.

In addition, the wireless charging method according to the embodiment, the second step of changing the power transmission contract, power transmission stop step; Reconnecting with the wireless power receiver; Receiving a generic request packet requesting a power transmitter capability packet for a power transfer contract after transitioning to a negotiation step; And transmitting a power transmitter capability packet including a first guaranteed power value in response to the general request packet.

In addition, the wireless charging method according to the embodiment, the first step of changing the power transmission contract, the step of transitioning to the renegotiation step; Receiving a generic request packet requesting a power transmitter capability packet for a power transfer contract after a transition to a renegotiation step; And transmitting a power transmitter capability packet including a second guaranteed power value in response to the general request packet.

In the wireless charging method according to the embodiment, the transition to the renegotiation step may include transmitting a NAK packet when receiving a received power packet from a wireless power receiver.

In addition, the wireless charging method according to the embodiment, the second step of changing the power transmission contract, transitioning to the renegotiation step; Receiving a generic request packet requesting a power transmitter capability packet for a power transfer contract after a transition to a renegotiation step; And transmitting a power transmitter capability packet including a first guaranteed power value in response to the general request packet.

In the wireless charging method according to the embodiment, the transition to the renegotiation step may include transmitting a NAK packet when receiving a received power packet from a wireless power receiver.

In accordance with another aspect of the present invention, there is provided a wireless power transmitter including: a power transmitter including at least one transmitting coil and a driver controlling an output power provided to the at least one transmitting coil; A power converter converting the intensity of power applied from the outside to provide the output power; And a controller configured to control a charging mode and charging power for the wireless power receiver, wherein the charging mode includes a first charging mode and a second charging mode, and the controller is in a charging mode while performing charging in the second charging mode. The controller determines whether the battery is in a limited state, and the controller performs a first charging mode changing from the second charging mode to the first charging mode when the charging mode is limited, and the controller controls the first charging mode by changing the charging mode. The controller may determine whether the charging mode restriction release state is performed while the charging operation is performed, and when the charging mode restriction release state is performed, the controller may perform a second charging mode change from the first charging mode to the second charging mode.

In addition, in the wireless power transmitter according to the embodiment, the first charging mode is a low power charging mode, the second charging mode is a high power charging mode, and the charging mode restriction state is caused by an event of the wireless power receiver. The control mode is a state of controlling to reduce the intensity of the charging power to be supplied, wherein the charge mode restriction release state is a state in which the wireless power receiver stops the control of the charging power supplied by the wireless power transmitter due to an event, and the control unit limits the charging mode. State to provide a higher charging power to the wireless power receiver in a first charging mode than a second charging mode, and the controller is configured to provide higher charging power in a second charging mode than a first charging mode when the charging mode is restricted. It may be provided to the wireless power receiver.

In addition, the wireless power transmitter according to the embodiment further includes a sensing unit having a current sensor, the current sensor senses a driving current applied to the driving unit, the control unit is the sensed drive current value is the first threshold current value When the first state below is maintained for a first time, it is determined that the charging mode is restricted. When the second state where the sensed driving current value is greater than or equal to a second threshold current value is maintained for a second time, the charging mode limitation is released. It can be determined that the state.

In addition, the wireless power transmitter according to the embodiment, the first change of the charging mode, the control unit reconnects to the wireless power receiver after stopping the power transmission in the second charging mode, requesting the second charging mode received from the wireless power receiver The charging may be performed in the first charging mode ignoring the first response packet.

In addition, in the first change of the charging mode, the wireless power transmitter according to the embodiment may ignore the first response packet if the reconnection time taken for the reconnection is within a critical reconnection time.

In addition, the wireless power transmitter according to the embodiment further includes a sensing unit having an operating frequency sensor, the operating frequency sensor senses the operating frequency of the output power provided to the at least one transmitting coil, the control unit is the sensed operation If the third state having the frequency value equal to or greater than the first threshold frequency value is maintained for the third time, it is determined that the charging mode is restricted, and the controller determines that the fourth state where the sensed operating frequency value is equal to or less than the second threshold frequency value is fourth; If it is maintained for a period of time, it may be determined that the charging mode is restricted.

The wireless power transmitter may further include a sensing unit including an operating frequency sensor and an operating duty ratio sensor, wherein the operating frequency sensor senses an operating frequency of output power provided to the one or more transmitting coils, and operates The duty ratio sensor senses an operating duty ratio of the output power provided to the at least one transmitting coil, and the controller is configured such that the sensed operating frequency value is greater than or equal to a third threshold frequency value and the sensed operating duty ratio is a first threshold duty ratio. When the fifth state, which is less than or equal to the fifth state, is determined to be in a charging mode restriction state, the controller determines that the sensed operating duty ratio of which the sensed operating frequency value is less than or equal to a fourth threshold frequency value is greater than or equal to a second threshold duty ratio When the state is maintained for the sixth time, it may be determined that the charging mode is restricted.

In addition, the wireless power transmitter according to the embodiment changes the first charging mode, the control unit reconnects to the wireless power receiver after stopping power transmission in the second charging mode, and does not transmit the first packet indicating the second charging mode support. The charging may be performed in the first charging mode.

In addition, in the first change of the charging mode, the wireless power transmitter according to the embodiment may ignore the first response packet if the reconnection time is within a threshold reconnection time.

In addition, the wireless power transmitter according to the embodiment, if the second change of the charging mode, when the control unit receives a first response packet requesting the second charging mode from the wireless power receiver after transmitting the first packet indicating the second charging mode support. Charging may be performed in the second charging mode.

In accordance with another aspect of the present invention, there is provided a wireless power transmitter including: a power transmitter including at least one transmitting coil and a driver controlling an output power provided to the at least one transmitting coil; A power converter converting the intensity of DC power applied from the outside to provide the output power; A communication unit exchanging information with an external device; And a control unit for transmitting a packet through the communication unit to change a power transmission contract for guaranteed power which is a power intensity value transmitted by the power transmitter in a power transmission step, wherein the guaranteed power includes a first guaranteed power and a second guaranteed power. And the control unit determines whether a guaranteed power limit state is being performed while charging with the first guaranteed power, and wherein the control unit changes from the first guaranteed power to the second guaranteed power when the guaranteed power limited state. Perform the change, and the controller determines whether the guaranteed power limit release state is being performed while charging with the second guaranteed power by the first change of the power transmission contract; A second change in the power transfer agreement that changes to the 1 guaranteed power may be performed.

In addition, in the wireless power transmitter according to the embodiment, the first guaranteed power is high power, the second guaranteed power is low power, and the guaranteed power limited state is charged by the wireless power receiver by the wireless power transmitter due to an event of the wireless power receiver. The control power is controlled to reduce the strength of the control unit, and the guaranteed power limit release state is a state in which the wireless power receiver stops controlling the charging power supplied by the wireless power transmitter due to an event, and the controller controls the first control unit to set the guaranteed power limit state. Provide the wireless power receiver with a higher charging power at a second guaranteed power than the guaranteed power, and wherein the controller is configured to provide higher charging power at a first guaranteed power than a second guaranteed power when the guaranteed power is de-restricted. Can be provided to

In addition, the wireless power transmitter according to the embodiment, the first change in the power transmission contract, the control unit reconnects to the wireless power receiver after stopping the power transmission at the first guaranteed power, and transmits a power transmitter capability packet including a second guaranteed power value. And performing charging at a second guaranteed power, wherein the second change of the power transmission contract is performed by the control unit reconnecting with the wireless power receiver after the power transmission stops at the first guaranteed power, and including the first guaranteed power value. It may be to transmit a transmitter capability packet to perform charging at a second guaranteed power.

In addition, the wireless power transmitter according to the embodiment, the first change in the power transmission contract, the control unit reconnects to the wireless power receiver after the power transmission stops at the first guaranteed power, the second guaranteed power value is included after the transition to the renegotiation step Transmitting a power transmitter capability packet to perform charging with a second guaranteed power, wherein the second change of the power transfer contract is such that the control unit reconnects to the wireless power receiver after stopping power transmission at the first guaranteed power and transitions to a renegotiation step. Thereafter, the power transmitter capability packet including the first guaranteed power value may be transmitted to perform charging with the second guaranteed power.

In addition, when the wireless power transmitter transitions to the renegotiation step, when receiving a received power packet from the wireless power receiver, the wireless power transmitter may transmit a NAK packet.

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.

The present invention can be used in the field of wireless power transmission and reception.

Claims (10)

A wireless charging method in a wireless power transmitter for wirelessly transmitting power to a wireless power receiver, Performing charging in a second charging mode; Determining whether the charging mode is restricted while performing charging in the second charging mode; A first charging mode changing step of changing from a second charging mode to a first charging mode when the charging mode is restricted; And Performing charging in a first charging mode; The charging mode restriction state is a state of controlling the wireless power receiver to reduce the strength of the charging power supplied by the wireless power transmitter due to an event of the wireless power receiver. According to claim 1, Determining whether the charge mode restriction release state is being performed while charging in the first charge mode; And A second charging mode changing step of changing from a first charging mode to a second charging mode when the charging mode restriction release state; The charging mode restriction release state is a state in which a wireless power receiver stops charging power control provided by a wireless power transmitter due to an event. According to claim 1, Determining whether the charging mode is restricted while performing charging in the second charging mode, Sensing a drive current; Determining whether the sensed driving current value is in a first state equal to or less than a first threshold current value; And Determining whether the first state is maintained for a first time. The method of claim 2, Determining whether the charge mode restriction release state, Sensing a drive current; Determining whether the sensed drive current value is in a second state equal to or greater than a second threshold current value; And Determining whether the second state is maintained for a second time. The method of claim 1 The first charging mode changing step, Stopping power transmission; Reconnecting with the wireless power receiver; Receiving a packet for initial power control after transitioning to a power transfer step; And And not transmitting the first packet indicating the second charging mode support. The method of claim 2, The second charging mode changing step, Transmitting a first packet to announce second charging mode support; Receiving a first response packet requesting a second charging mode when transmitting the first packet; And And charging in the second charging mode upon receiving the first response packet. A wireless charging method in a wireless power transmitter for wirelessly transmitting power to a wireless power receiver, Performing charging at a first guaranteed power; Determining whether a guaranteed power limit state is being performed while charging with the first guaranteed power; Changing a first power transmission contract from a first guaranteed power to a second guaranteed power when the guaranteed power is limited; And And performing charging at a second guaranteed power. The method of claim 7, wherein Determining whether a guaranteed power limit is released while charging is performed at a second guaranteed power; And And a second modification step of changing a power transmission contract from a second guaranteed power to a first guaranteed power when the guaranteed power limit is released. A power transmitter including at least one transmitting coil and a driver controlling an output power provided to the at least one transmitting coil; A power converter converting the intensity of power applied from the outside to provide the output power; And a controller configured to control a charging mode and charging power for the wireless power receiver. The charging mode includes a first charging mode and a second charging mode, The controller determines whether the charging mode is restricted while performing charging in the second charging mode, The controller performs a first charging mode change to change from a second charging mode to a first charging mode when the charging mode is restricted. The controller determines whether the charging mode restriction release state is performed while charging the first charging mode by changing the charging mode first, The control unit performs a second change of the charging mode to change from the first charging mode to the second charging mode when the charging mode restriction release state. A power transmitter including at least one transmitting coil and a driver controlling an output power provided to the at least one transmitting coil; A power converter converting the intensity of DC power applied from the outside to provide the output power; A communication unit exchanging information with an external device; And A control unit for transmitting a packet through the communication unit to change a power transmission contract for guaranteed power which is a power intensity value transmitted by the power transmitter in a power transmission step; The guaranteed power includes a first guaranteed power and a second guaranteed power, The controller determines whether a guaranteed power limit state is being performed while charging with the first guaranteed power, The control unit performs a first change of the power transmission contract to change from the first guaranteed power to the second guaranteed power when the guaranteed power limited state, The controller determines whether the guaranteed power limit is released while performing charging with a second guaranteed power by the first change of the power transmission contract, And the control unit performs a second change of the power transmission contract to change from the second guaranteed power to the first guaranteed power when the guaranteed power limit is released.

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