WO2018208036A1 - Wireless charging method, and apparatus and system for same - Google Patents

Abstract

The present invention relates to a wireless power transmission technique and, more particularly, to a wireless charging method, and an apparatus and a system for the same. A wireless charging method by which a wireless power transmitter wirelessly transmits power to a wireless power receiver, according to one embodiment, comprises the steps of: receiving a control error packet in a power transmission step; adjusting transmission power according to a control error value of the received control error packet; receiving a received power packet; receiving a signal strength packet; and determining whether to apply the power control offset.

Description

Wireless charging method, apparatus and system therefor

TECHNICAL FIELD The present invention relates to wireless power transfer technology, and more particularly, to a wireless charging method, 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, as a wireless power transmission method, various wireless power transmission standards based on an electromagnetic induction method that generates a magnetic field in a power transmitter coil and charges using an electromagnetic induction principle in which electricity is induced in a receiver coil under the influence of the magnetic field may be used. . 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, as a wireless power transmission method, 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 a wireless power transmitter to a specific resonance frequency may be used. . 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, an RF wireless power transmission method for transmitting power to a wireless power receiver located at a far distance by loading low power energy into the RF signal may be used as the wireless power transmission method.

On the other hand, the wireless power receiver may cause a problem of battery damage when the battery to be charged receives a high intensity charging power above a predetermined charging rate or below a predetermined charging rate. Here, the charge rate or more means a fully charged state or a state close to full charge, and the charge rate or less means, for example, a full discharge state or a state close to full discharge. In addition, when the wireless power receiver receives charging power of too low intensity, a problem may occur in that the battery is not charged.

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

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

Still another object of the present invention is to provide a wireless charging method, apparatus and system therefor, which enable a wireless power receiver to control charging power.

Still another object of the present invention is to provide a wireless charging method, an apparatus and a system therefor, which enable a wireless power transmitter to control charging power.

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 solve the problem that the fully discharged battery is not charged.

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 of the wireless charging method in a wireless power transmitter for transmitting power wirelessly to the wireless power receiver, receiving a control error packet in the power transmission step ; Adjusting outgoing power according to a control error value of the received control error packet; Receiving a received power packet; Receiving a signal strength packet; And determining whether to apply the power control offset.

Also, in the wireless charging method according to the embodiment, adjusting the transmission power according to the control error value of the received control error packet, if the control error value is negative, reduce the transmission power, and if the control error value is positive, Can increase power.

In addition, in the wireless charging method according to the embodiment, the control error value of the control error packet may be negative.

In the wireless charging method according to the embodiment, the step of determining whether to apply the power control offset may be determined to apply the power control offset when the received power value of the received received power packet is less than the first threshold power. .

In addition, in the wireless charging method according to the embodiment, the first threshold power may be 1500 mW or less.

In addition, the wireless charging method according to the embodiment includes the step of initiating the application of the power control offset; Receiving a control error packet during application of the power control offset; And adjusting the transmission power by applying the power control offset to the control error value of the received control error packet during the application of the power control offset.

In the wireless charging method according to the embodiment, in the step of adjusting the transmission power by applying the power control offset to the control error value of the control error packet, the power transmission offset value may be adjusted by adding the power control offset value to the control error value.

In addition, the wireless charging method according to the embodiment comprises the steps of receiving a received power packet during the application of the power control offset; And determining whether to release the power control offset. The determining of whether to apply the power control offset may include: if the received power of the received power packet is greater than or equal to a second threshold power, power control; The application of the offset may be determined to be released, and the second threshold power may be greater than the first threshold power.

In addition, in the wireless charging method according to the embodiment, the second threshold power may be 2,500 mW or more.

In addition, the wireless charging method according to the embodiment may further include adjusting the transmission power according to the control error value of the received control error packet after the application of the power control offset.

In addition, the wireless charging method according to the embodiment comprises the steps of determining whether to receive a signal strength packet during the application of the power control offset; Determining whether to apply n-th (n is a natural number of 2 or more) power control offset when receiving a signal strength packet during application of power control offset; Initiating application of the nth power control offset; Receiving a control error packet during application of the nth power control offset; And adjusting outgoing power by applying an n-th power control offset to a control error value of the received control error packet during the application of the n-th power control offset. The determining may include determining that the n th power control offset is to be applied when the received power value of the received power packet is equal to or less than a first threshold power, and the control error packet received during the application of the n th power control offset. Adjusting the output power by applying the n-th power control offset to the control error value, by adding the accumulated value of the first to n-th power control offset value to the control error value received during the application of the n-th power control offset. Output power can be adjusted.

In addition, in the wireless charging method according to the embodiment, the power control offset value may be greater than the n th power control offset value.

In the wireless charging method according to the embodiment, the receiving of the control error packet in the power transmission step may continuously receive the control error packet having a negative control error value.

The wireless charging method may further include using identification packet information received from a wireless power receiver. The wireless power transmitter may determine whether to apply the power control offset. Application of the power control offset can optionally be made.

In one embodiment, a wireless charging method includes: receiving a control error packet in a power transmission step in a wireless charging method in a wireless power transmitter for wirelessly transmitting power to a wireless power receiver; Adjusting outgoing power according to a control error value of the received control error packet; Receiving a received power packet; Receiving a signal strength packet; Stopping power transmission; And determining whether to apply the nth (n is a natural number) power control offset after the transition to the power transmission step.

In addition, the wireless charging method according to the embodiment includes initiating the application of the n-th power control offset; Receiving a control error packet during application of the nth power control offset; And adjusting the transmission power by applying a power control offset to a control error value of the received control error packet during the application of the n-th power control offset.

In addition, the wireless charging method according to the embodiment comprises the steps of determining whether to receive a signal strength packet during the application of the n-th power control offset; Stopping power transmission when receiving the signal strength packet during the application of the nth power control offset; Determining whether to apply the n + 1th power control offset after the transition to the power transmission step; Initiating application of the n + 1 power control offset; Receiving a control error packet during application of the n + 1 power control offset; And adjusting outgoing power by applying an n + 1 power control offset to a control error value of a received control error packet during the application of the n + 1 th power control offset. In determining whether to apply the control offset, if the received power value of the received power packet is less than the first threshold power, it is determined to apply the n + 1 power control offset, and the n + 1 power control offset Adjusting the outgoing power by applying the n + 1 power control offset to the control error value of the control error packet received during the application of, the first to the control error value received during the application of the n + 1 power control offset; The output power may be adjusted by adding the accumulated value of the n th to the n + 1 th power control offset values.

In addition, the wireless charging method according to the embodiment comprises the steps of receiving a received power packet during the application of the n-th power control offset; And determining whether to release the power control offset. The determining of whether to apply the power control offset may include: if the received power of the received power packet is greater than or equal to a second threshold power, power control; The application of the offset may be determined to be released, and the second threshold power may be greater than the first threshold power.

In addition, the wireless charging method according to the embodiment may further include adjusting the transmission power according to the control error value of the control error packet received after the application of the power control offset.

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 providing transmission power to the at least one transmitting coil; A power converter for converting the intensity of power applied from the outside to provide the transmission power; A communication unit exchanging information with an external device; And a control unit controlling the driving unit based on the information received from the communication unit, wherein the communication unit receives a control error packet and a received power packet, and the control unit transmits power according to a control error value of the control error packet. The controller may determine whether to apply a power control offset by using the received power packet when the communication unit receives the signal strength packet in the power transmission step.

In addition, the wireless power transmitter according to the embodiment, the control unit determines that the power control offset is applied if the received power value of the received power packet is less than the first threshold power.

In addition, in the wireless power transmitter according to the embodiment, the first threshold power may be 1500 mW or less.

In addition, the wireless power transmitter according to the embodiment may adjust the transmission power by applying the power control offset to the control error value of the control error packet received during the application of the power control offset.

In addition, in the wireless power transmitter according to the embodiment, the application of the power control offset may add the power control offset value to the control error value.

In addition, the wireless power transmitter according to the embodiment, the communication unit receives the received power packet during the application of the power control offset, the control unit, the received power of the received power packet received during the application of the power control offset is the second threshold power If it is above, it is determined to cancel the application of the power control offset, and the second threshold power may be greater than the first threshold power.

In addition, in the wireless power transmitter according to the embodiment, the second threshold power may be 2500 mW or more.

In addition, in the wireless power transmitter according to the embodiment, the communication unit may continuously receive a control error packet having a negative control error value.

In addition, the wireless power transmitter according to the embodiment, the communication unit receives the identification packet, the control unit may selectively apply the power control offset in accordance with the identification packet information.

In addition, the wireless power transmitter according to the embodiment, when the communication unit receives the received power packet during the application of the power control offset, and the control unit receives a signal strength packet during the application of the power control offset n (n is a natural number of two or more) It is determined whether the power control offset is applied, and the control unit applies an nth power control offset when the received power value of the received power packet is less than or equal to a first threshold power during the application of the power control offset, and the communication unit The control error packet may be received during the application of the n-th power control offset, and the controller may adjust the transmission power by applying the n-th power control offset to the control error value of the control error packet received during the application of the n-th power control offset. .

In addition, in the wireless power transmitter according to the embodiment, the application of the n th power control offset may add a cumulative value of the first to n th power control offset values to a control error value received during the application of the n th power control offset. have.

Also, in the wireless power transmitter according to the embodiment, the power control offset value may be greater than the n th power control offset value.

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 providing transmission power to the at least one transmitting coil; A power converter for converting the intensity of power applied from the outside to provide the transmission power; A communication unit receiving a control error packet and a received power packet; A storage unit which stores information of the received received power packet and signal strength packet information; And a control unit controlling the driving unit based on the information received from the communication unit, wherein the control unit stops power transmission when the communication unit receives a signal strength packet in the power transmission step, and after the transition to the power transmission step, When the received power value of the received received power packet is equal to or less than the first threshold power, it may be determined whether n (n is a natural number) power control offset is applied.

The wireless power transmitter according to the embodiment may determine that the control unit applies the nth power control offset when the received power value of the received received power packet is equal to or less than a first threshold power, and the communication unit controls the nth power control. The control error packet may be received during the application of the offset, and the controller may adjust the transmission power by applying the power control offset to the control error value of the control error packet received during the application of the nth power control offset.

In addition, the wireless power transmitter according to the embodiment, the communication unit receives a received power packet during the application of the n-th power control offset, the control unit stops power transmission when receiving a signal strength packet during the application of the n-th power control offset. And determining whether to apply the n + 1 power control offset after the transition to the power transmission step, and if the received power value of the received power packet received during the nth power control offset application is equal to or less than a first threshold power Applies a +1 power control offset, the communication unit receives a control error packet during the application of the n + 1 power control offset, and the controller controls a control error value received during the application of the n + 1 power control offset The output power can be adjusted by adding the accumulated value of the 1 to n + 1th power control offset values.

In addition, the wireless power transmitter according to the embodiment, the communication unit receives the received power packet during the application of the n-th power control offset, the control unit, the received power of the received power packet received during the application of the n-th power control offset If it is greater than or equal to the second threshold power, it is determined to cancel the application of the power control offset, and the second threshold power may be greater than the first threshold power.

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 protect the load by controlling the charging power of the wireless power transmitter.

In addition, according to the present invention, the wireless power transmitter may control charging power to charge a fully discharged battery.

In addition, the present invention can increase the wireless charging speed by the wireless power transmitter to control the charging power.

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

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

7 is a diagram for describing a packet format according to a wireless power transmission procedure according to an embodiment.

8 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.

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

10 is a diagram illustrating a message format of a configuration packet and a power control suspend packet according to a wireless power transmission procedure according to an embodiment.

11 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.

12 is a graph illustrating a change in charging power input to a wireless power receiver according to a charging rate in order to explain trickle charging.

FIG. 13 is a graph illustrating a change in charge rate of a battery with time for explaining a problem caused by trickle charge in a fully discharged state of the battery.

14 is a diagram for describing a wireless charging method on a wireless charging system, 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 graph illustrating a change in charge rate of a battery with time by a wireless charging system according to an exemplary embodiment.

17 is a view for explaining a wireless charging method on a wireless charging system according to another embodiment.

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

19 is a diagram for describing a wireless charging method on a wireless charging system, according to another embodiment.

20 is a diagram for describing a wireless charging method of 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 measure the voltage / current of the DC-converted power and provide the same to the controller 440. In addition, the sensing unit 450 may measure the internal temperature of the wireless power transmitter 400 to determine whether overheating occurs, and provide the measurement result to the controller 440. For example, the controller 440 may adaptively block power supply from the power supply unit 450 or block power from being supplied to the amplifier 412 based on the voltage / current value measured by the sensing unit 450. Can be. 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.

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 includes a received power indicator, a signal strength indicator, an identification indicator, a configuration indicator, an error correction (EC) indicator for power control during wireless power transmission, an end of charge (EOC) indicator, and an overvoltage It may include / over current / overheat indicator, but is not limited thereto, and may include various state information for identifying the 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.

The storage unit 470 may store packet information received according to the wireless power transmission procedure of FIGS. 2 to 3. More specifically, the storage unit 470 may receive any one of a signal strength packet transmitted in the ping step and a configuration packet transmitted in the configuration and identification step, and a packet transmitted in the configuration and identification step. In this case, information of the packet received in the power transmission step 240 or 360 may be stored. The controller 440 may use the stored packet information to determine whether to apply the power control offset. In addition, when the power transmission is stopped, the storage unit 470 may store the received power value of the received power packet immediately before the power transmission is stopped. The controller 440 may be used to determine whether to apply the power control offset using the stored received power value.

In addition, the controller 440 may apply a power control offset when adjusting the transmission power according to the power control signal received from the wireless power receiver. Detailed description thereof follows the wireless charging method described below. That is, the wireless power transmitter according to an embodiment may control the charging power by applying the power control offset to the power control value of the power control signal. The power control signal may include control error packet information. In addition, the power control value may include a control error value of the control error packet. In addition, the wireless power transmitter according to an embodiment controls the charging power by applying the power control offset, thereby protecting the battery of the wireless power receiver. In addition, the wireless power transmitter according to an embodiment may charge the fully discharged battery of the wireless power receiver by applying the power control offset.

FIG. 5 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. 5, 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 shown in the example of FIG. 5 is illustrated as being capable of exchanging information with the wireless power transmitter 400 through in-band communication, this is only one embodiment, and is another example. 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.

In addition, when the strength of the rectifier output DC power is less than or equal to a predetermined reference value, the main controller 670 may determine that power transmission is stopped, and any one of a signal strength packet, a configuration packet, and an identification packet may be modulated by the modulator 662. It can be controlled to be transmitted to the wireless power transmitter through.

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 control the strength of the charging power transmitted from the wireless power transmitter based on the battery charging rate. For example, when it is determined that the battery charge rate is greater than or equal to a predetermined reference value or the buffer state, 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 the above-described power control signal or a control error packet described later. Accordingly, the main controller 670 may protect the battery by preventing the battery from being charged rapidly by reducing the charging power when the battery is close to the fully charged state. As another example, when it is determined that the battery charge rate is less than or equal to a predetermined reference value or the discharge state stage, the main controller 670 may generate and transmit a power control packet to reduce the intensity of the charging power transmitted from the radio power transmitter. Accordingly, the main controller 670 may protect the battery by gradually reducing the charging power when the battery is close to the discharged state.

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

As shown in reference numeral 710 of FIG. 6, 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 5.

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.

7 is a diagram for describing a packet format according to a wireless power transmission procedure according to an embodiment.

FIG. 7 may mainly be a packet format according to the first wireless power transfer procedure of FIG. 2. That is, the packet format of FIG. 7 may be a packet format also used for the second wireless power transfer procedure of FIG. 3.

Referring to FIG. 7, the packet format 800 used for information exchange between the wireless power transmitter 10 and the wireless power receiver 20 may be used to obtain synchronization for demodulating 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 illustrated in FIG. 7, the packet receiver 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. 7, it should be noted that header values corresponding to end power transfer of the ping step and end of 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.

8 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. 8, 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. 8, 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. 8, 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.

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

Referring to FIG. 9, 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.

10 is a diagram illustrating 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. 10, 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.

11 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. 11, a packet that can be transmitted 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.

12 is a graph illustrating a change in charging power input to a wireless power receiver according to a charging rate in order to explain trickle charging.

Referring to FIG. 12, the wireless power receiver may control the charging power transmitted from the wireless power transmitter according to the battery charging rate. More specifically, the wireless power receiver may perform trickle charging when the battery charge rate is less than or equal to a predetermined reference value. Trickle charging is to charge the battery by lowering the strength of the current charged in the battery. Trickle charge may be referred to as trickle charge. The wireless power receiver may control to reduce the intensity of the charging power transmitted from the wireless power transmitter for trickle charging. For example, as shown in FIG. 12, the wireless power receiver may control the charging power to be less than or equal to b [W] when the battery is in a discharged state or when the charge rate of the battery is less than or equal to P1 [%] close to the discharged state. The first section T1 may be a section in which the battery performs trickle charge from 0% or more to P1 (%) or less. That is, the charging power may be lower than b [W] starting at the lowest a [W] during the first period T1. In addition, during the first period T1, the wireless power receiver may continuously provide a control error packet including a negative control error value to the wireless power transmitter in order to lower charging power to the wireless power transmitter. The charging power may be greater than or equal to b [W] at P2 [%] at P1 [%]. The second section T2 may be a section in which the battery performs charging according to a power transmission contract until P1 [%] or more and P2 [%] or less. That is, the charging power can reach a maximum of c [W] according to the power transmission contract. The wireless power receiver may control less than b [W] when the battery is fully charged or when the battery charge rate is greater than or equal to P2 [%] close to the fully charged state. The third section T3 may be a section in which the battery performs trickle charge from P2 [%] or more to 100 [%] or less.

FIG. 13 is a graph illustrating a change in charge rate of a battery with time for explaining a problem caused by trickle charge in a fully discharged state of the battery.

Referring to FIG. 13, the wireless power receiver may perform trickle charging in a fully discharged state of the battery. When the charging rate reaches a predetermined reference value, the wireless power receiver may generate a predetermined event such as booting of the system or operation of a screen screen. For example, as shown in FIG. 13, the wireless power receiver may consume the charged power by the operation of the screen screen at the first time point t1 when the charging rate of the battery becomes 1 [%]. In this case, since the consumed power is larger than the charging power due to trickle charging, the wireless power receiver may be completely discharged of the battery. The reason why the charging power is lower than the consumed power is because the wireless power receiver lowers the transmission power transmitted from the wireless power transmitter to perform trickle charging. As a result, the wireless power receiver is discharged due to power consumption due to a predetermined event at points (t1, t2, t3, etc.) when the battery charge rate becomes 1 [%] and repeats charging and discharging, and the battery is not charged. May occur.

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

In detail, FIG. 14 is a flowchart for describing a procedure of performing a power control offset on a wireless charging system.

Referring to FIG. 14, before the wireless charging starts, the battery may be discharged (S1401). More specifically, the battery may be in a fully discharged state. The battery is not limited thereto, and the battery may be below a predetermined charge rate. In addition, although the battery is illustrated as being included in the electronic device 1430, the wireless power receiver 1420 may be included in the electronic device 1430 and the battery may be included in the wireless power receiver 1420, but the present invention is not limited thereto.

The wireless power receiver 1420 may start trickle charging after the transition to the power transmission step in the identification and configuration step (S1402). More specifically, the wireless power receiver 1420 may perform trickle charging according to the state of charge of the battery. The trickle charging may be performed by the wireless power receiver 1420 when the battery is fully discharged or when the battery is below a predetermined charge rate. The wireless power receiver 1520 may control charging power transmitted from the wireless power transmitter 1410 by a control error packet (CEP) for trickle charging.

The wireless power transmitter 1410 may receive the control error packet CEP from the wireless power receiver 1420 (S1403). The wireless power receiver 1420 may adjust the strength of the transmission power based on the control error value of the received control error packet (CEP). More specifically, the control error value of the control error packet (CEP) transmitted for trickle charging may be a negative value. The wireless power transmitter 1410 may reduce the strength of the transmission power based on a control error value that is a negative value.

In addition, the wireless power transmitter 1410 may continuously receive a control error packet CEP (S1404). The control error values of consecutively received control error packets CEP may be negative for trickle charge of the wireless power receiver 1420.

The wireless power transmitter 1410 may receive a received power packet (RPP) (S1405). The wireless power transmitter 1410 may determine the strength of the charging power currently being received by the wireless power receiver 1420 by the received power packet RRP. The wireless power transmitter 1410 may receive a received power packet (RPP) during the trickle charging period T1.

The electronic device 1430 may consume energy charged in the battery as power due to a predetermined event, and the battery may be discharged (S1406 to S1407). The predetermined event may mean that the charging rate of the battery reaches a predetermined reference value, such that booting of the system of the electronic device 1430 or operation of the screen screen is performed. The battery discharge may be a momentary full discharge state of a battery due to a predetermined event or a state in which charging power for battery charging is insufficient.

The wireless power transmitter 1410 may receive a signal strength packet (S1408). That is, the wireless power receiver 1420 determines that power transmission is stopped because the received power is less than or equal to a predetermined reference value, and thus transmits a signal strength packet. Without being limited to the signal strength packet, the wireless power transmitter 1410 may receive any one of a signal strength packet, a configuration packet, and an identification packet.

The wireless power transmitter 1410 may determine whether to apply the power control offset based on the received signal strength packet and the received power packet (S1409). When the power control offset is applied, the wireless power transmitter 1410 may adjust the transmission power by applying the power control offset value to the control error value of the received control error packet (S1410). Accordingly, the wireless power transmitter 1410 controls the charging power by applying a power control offset. Whether to apply the power control offset of the wireless power transmitter 1410 and the method of applying the power control offset will be described in detail in the wireless charging method in the wireless power transmitter according to the embodiment of FIG.

The electronic device 1430 may consume energy charged in the battery as power due to a predetermined event (S1411). As in S1406, the electronic device 1430 may perform a specific operation of consuming power when the charging rate of the battery reaches a predetermined reference value. The difference from S1407 is that the wireless power transmitter 1410 transmits transmission power by applying a power control offset. Thus, the battery may be larger than the consumed power consumption of the received transmission power so that the battery can be charged normally.

The wireless power transmitter 1410 may receive a received power packet (RPP) (S1412). The wireless power transmitter 1410 may receive a received power packet (RPP) during the power control offset application period T2.

The wireless power transmitter 1410 may determine whether to release the power control offset based on the received received power packet, and perform the power control offset release (S1413). When the power control offset application is released, the wireless power transmitter 1410 may adjust the transmission power according to the control error value of the received control error packet (S1414).

The wireless power receiver 1420 may terminate the trickle charge when the battery charge rate is greater than or equal to a predetermined reference value (S1415). When the wireless power receiver 1420 ends the trickle charge, the wireless power receiver 1420 may control the charging power to receive the guaranteed power according to the power transmission contract.

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 transmitter enters a power transmission step, it may receive a control error packet (S1501). Although not shown, the wireless power receiver may set a control error value of the control error packet according to the battery charge rate and transmit the control error value to the wireless power transmitter. More specifically, the wireless power receiver may perform trickle charging when the charging rate at which the battery is fully discharged is 0% or close to 0%. For trickle charging, the wireless power receiver may determine a control error value to transmit charging power lower than the guaranteed power of the power transmission contract. For example, the control error value may be a negative value.

The wireless power transmitter may adjust the transmission power according to the control error value of the received control error packet (S1502). If the control error value of the received control error packet is negative, the wireless power transmitter may reduce the intensity of the transmission power. In addition, the wireless power transmitter may adjust the degree of reduction of the transmission power according to the negative level of the control error value.

The wireless power transmitter may receive the received power packet (S1503). More specifically, the wireless power transmitter may receive the received power packet at a predetermined cycle. The received power packet may include a received power value that is information on the strength of the received power received by the wireless power receiver.

The wireless power transmitter may receive the signal strength packet (S1504). Without being limited thereto, the wireless power transmitter may receive one of a signal strength packet transmitted in the ping step, a configuration packet transmitted in the configuration and identification step, and an identification packet.

Upon receiving the signal strength packet, the wireless power transmitter may determine whether the received power is equal to or less than the first threshold power in order to determine whether to apply the power control offset (S1506). When the wireless power transmitter receives a signal strength packet not received in the power transmission step, the wireless power transmitter may determine whether to apply the power control offset. The first threshold power may be a received power value that is insufficient for the battery to be charged due to power consumption due to a predetermined event during wireless charging. In addition, the first threshold power may be a preset power value. In addition, the first threshold power may be 1,500 mW or less. More specifically, the first threshold power may be 1,100 mW. Although not limited thereto, a first threshold voltage or a first threshold current may be used instead of the first threshold power to determine whether to apply the power control offset. Also, although not shown, the determination of whether to apply the power control offset may further include determining information on the wireless power receiver of the received identification packet or configuration packet. The wireless power transmitter may not need to apply the power control offset according to the unique information of the wireless power receiver. In this case, the wireless power transmitter may selectively determine whether to apply the power control offset. Also, although not shown, the determination of whether to apply the power control offset may further include determining a type of a wireless power transmission procedure of a standard supported by the wireless power transmitter and the wireless power receiver. The wireless power transmitter may not need to apply a power control offset according to the version information of the WPC standard. In this case, the wireless power transmitter may selectively determine whether to apply the power control offset.

If the received power is less than or equal to the first threshold power, the wireless power transmitter may start applying the power control offset (S1507). That is, the wireless power transmitter may determine that the strength of the transmission power for battery charging is insufficient and apply the power control offset. In addition, if the received power exceeds the first threshold power, the wireless power transmitter determines that the strength of the transmit power for charging the battery is sufficient and does not apply the power control offset to the control error value of the control error packet provided by the wireless power transmitter. Output power can be controlled without

During the application of the power control offset, the wireless power transmitter may receive a control error packet (S1508). The control error packet may include a control error value that is a negative value for trickle charge.

During the application of the power control offset, the wireless power transmitter may adjust the transmission power by applying the power control offset to the control error value of the control error packet (S1509). Application of the power control offset may be that the wireless power transmitter adds a predetermined offset value to the control error value of the control error packet. More specifically, the wireless power transmitter may adjust the output power by raising the control error value by a positive power control offset value to a negative control error value. For example, the control error value of the control error packet may be -100, which is a negative integer, and the power control offset value may be 10, which is a positive integer. In this case, the wireless power transmitter may adjust the output power by setting the power control value to −90, which is a control error value other than a control error value of −100 and a power control offset value. As another example, the control error value of the control error packet may be -100, which is a negative integer, and the power control offset value may be 5, which is a positive integer. In this case, the wireless power transmitter may adjust the output power by setting the power control value to −95, which is a control error value other than a control error value of −100 and a power control offset value. That is, the power control offset value may be adjusted for battery protection. Therefore, the wireless power transmitter according to an embodiment may control the charging power by applying a power control offset. In addition, the wireless power transmitter according to an embodiment may charge the fully discharged battery by controlling the charging power by applying the power control offset. In addition, the wireless power transmitter according to an embodiment may increase the transmission power by applying a power control offset, thereby increasing the wireless charging speed. In addition, the wireless power transmitter according to an embodiment may protect the battery by adjusting the power control offset value.

During the application of the power control offset, the wireless power transmitter may receive the received power packet (S1510).

During the application of the power control offset, the wireless power transmitter may determine whether the received power of the received power packet is greater than or equal to the second threshold power in order to determine whether to release the power control offset (S1511). The second threshold power may be a reception power value in which the charging power of the battery is higher than that of the battery. The second threshold power may be greater than the first threshold power. In addition, the second threshold power may be a preset power value. In addition, the second threshold power may be 2,500 mW or more. More specifically, the second threshold power may be 4,500 mW.

If the received power is greater than or equal to the second threshold power, the wireless power transmitter may release the application of the power control offset (S1512). That is, the wireless power transmitter may determine that the strength of the transmit power for charging the battery is sufficient to release the application of the power control offset. In this case, the wireless power transmitter may control the transmission power without applying the power control offset to the control error value of the control error packet provided by the wireless power receiver. In addition, when the received power is less than the second threshold power, the wireless power transmitter may determine that the strength of the transmit power for charging the battery is still insufficient, and may proceed to step S1508. In this case, the wireless power transmitter continues to apply the power control offset.

16 is a graph illustrating a change in charge rate of a battery with time by a wireless charging system according to an exemplary embodiment.

Referring to FIG. 16, the wireless power receiver according to the exemplary embodiment of FIG. 14 may perform trickle charging in a fully discharged state of the battery. When the charging rate reaches a predetermined reference value, the wireless power receiver may generate a predetermined event such as booting of the system or operation of a screen screen. For example, as shown in FIG. 16, at a first time point t1 and a third time point t3 when the charging rate of the battery becomes 1 [%], the wireless power receiver may consume the charged power by the operation of the screen screen. have. In the first time point t1, the wireless power receiver may completely discharge the battery because the power consumption is greater than the charging power due to trickle charging. Thereafter, the wireless power transmitter may control the charging power by applying the power control offset during the first period T1 from the second time point t2 to the fourth time point t4. In the third time point t3 after the second time point t2, the wireless power receiver does not completely discharge the battery because the charging power is greater than the power consumption. Accordingly, it can be seen that the charging of the battery proceeds normally even if the instantaneous power consumption is large as a predetermined event at the third time point t3. Thereafter, when the charging power is sufficiently high or the battery charging rate exceeds the predetermined reference value at the fourth time point t4, it is not necessary to apply the power control offset. That is, at the fourth time point t4, the wireless power transmitter may release the application of the power control offset.

17 is a view for explaining a wireless charging method on a wireless charging system according to another embodiment.

In detail, FIG. 17 is a flowchart illustrating a procedure of performing a power control offset on a wireless charging system.

Referring to FIG. 17, although not shown, the battery may be discharged before the wireless charging starts (not shown). More specifically, the battery may be in a fully discharged state. The battery is not limited thereto, and the battery may be below a predetermined charge rate. In addition, although the battery is illustrated as being included in the electronic device 1730, the wireless power receiver 1720 may be included in the electronic device 1730 so that the battery may be included in the wireless power receiver 1720.

In addition, after the battery is discharged, the wireless charging may be started to follow the wireless power transmission procedure in order of selection, ping, identification and configuration, and power transmission (not shown).

The wireless power receiver 1720 may start trickle charging after the transition to the power transmission step in the identification and configuration step (S1701). More specifically, the wireless power receiver 1720 may perform trickle charging according to the state of charge of the battery. The trickle charging may be performed by the wireless power receiver 1720 if the battery is fully discharged or if the battery is below a predetermined charge rate. The wireless power receiver 1720 may control the charging power transmitted from the wireless power transmitter 1710 by a control error packet (CEP) for trickle charging.

The wireless power transmitter 1710 may receive the control error packet CEP from the wireless power receiver 1720 (S1702). The wireless power receiver 1720 may adjust the strength of the transmission power based on the control error value of the received control error packet (CEP). More specifically, the control error value of the control error packet (CEP) transmitted for trickle charging may be a negative value. The wireless power transmitter 1710 may reduce the strength of the transmission power based on a control error value that is a negative value.

In addition, the wireless power transmitter 1710 may continuously receive a control error packet CEP (S1703). The control error values of consecutively received control error packets CEPs may all be negative for trickle charging of the wireless power receiver 1720.

The wireless power transmitter 1710 may receive a received power packet (RPP) (S1704). The wireless power transmitter 1710 may determine the strength of the charging power currently being received by the wireless power receiver 1720 by the received power packet RRP. The wireless power transmitter 1710 may receive a received power packet (RPP) during the trickle charging period T3.

The electronic device 1730 consumes energy charged in the battery as power due to a predetermined event, and the battery may be discharged (S1705 to S1706). The predetermined event may mean that the charging rate of the battery reaches a predetermined reference value and the booting of the system of the electronic device 1730 or the operation of the screen screen is performed. The battery discharge may be a momentary full discharge state of a battery due to a predetermined event or a state in which charging power for battery charging is insufficient.

The wireless power transmitter 1710 may receive a signal strength packet (SS) (S1707). That is, the wireless power receiver 1720 determines that power transmission is stopped because the received power is less than or equal to a predetermined reference value, and thus transmits a signal strength packet. The wireless power transmitter 1710 may receive any one of a signal strength packet, a configuration packet, and an identification packet, without being limited to the signal strength packet.

The wireless power transmitter 1710 may determine whether to apply the first power control offset based on the received signal strength packet and the received power packet (S1708). When the first power control offset is applied, the wireless power transmitter 1710 may adjust the transmission power by applying the first power control offset value to the control error value of the received control error packet (S1409). Therefore, the wireless power transmitter 1710 controls the charging power by applying the first power control offset. The power control offset application period T4 may be until the power control offset release from the first power control offset application. Whether the first to nth power control offsets of the wireless power transmitter 1710 and the first to nth power control offsets are applied to the wireless charging method in the wireless power transmitter according to another embodiment of FIG. 18 to be described later. Explain in detail.

The wireless power transmitter 1710 may receive a received power packet (RPP) (S1710). That is, during the application of the first power control offset, the wireless power transmitter 1710 may receive a received power packet (RPP).

The electronic device 1730 consumes energy charged in the battery as power due to a predetermined event, and the battery may be discharged (S1705 to S1706). For example, even if the wireless power transmitter transmits the transmission power by applying the first power control offset, the battery consumes momentarily a full discharge state of the battery or the battery charge because the magnitude of power consumption due to a predetermined event is larger than the reception power. The charging power may be insufficient.

The wireless power transmitter 1710 may receive a signal strength packet (SS) (S1713). That is, the wireless power receiver 1720 determines that power transmission is stopped because the received power is less than or equal to a predetermined reference value, and thus transmits a signal strength packet. The wireless power transmitter 1710 may receive any one of a signal strength packet, a configuration packet, and an identification packet, without being limited to the signal strength packet.

The wireless power transmitter 1710 may determine whether to apply the second power control offset based on the received signal strength packet and the received power packet (S1714). When the second power control offset is applied, the wireless power transmitter 1710 may adjust the transmission power by applying the second power control offset value to the control error value of the received control error packet (S1715). More specifically, applying the second power control offset may be to weight the second power control offset value to the first power control offset value while the first power control offset is applied. For example, when the first power control offset value is +10 and the second power control offset value is +5, the value applied to the control error value by applying the power control offset may be +15.

The wireless power transmitter 1710 may receive a received power packet (RPP) (S1716). That is, during the application of the second power control offset, the wireless power transmitter 1710 may receive a received power packet (RPP).

The electronic device 1730 consumes energy charged in the battery as power due to a predetermined event, and the battery may be discharged (S1717 to S1718). For example, even if the wireless power transmitter transmits the transmission power by applying the second power control offset, the battery consumes momentarily a full discharge state of the battery or the battery charge because the magnitude of power consumption due to the predetermined event is larger than the reception power. The charging power may be insufficient.

The wireless power transmitter 1710 may receive a signal strength packet (SS) (S1719). That is, the wireless power receiver 1720 determines that power transmission is stopped because the received power is less than or equal to a predetermined reference value, and thus transmits a signal strength packet. The wireless power transmitter 1710 may receive any one of a signal strength packet, a configuration packet, and an identification packet, without being limited to the signal strength packet.

The wireless power transmitter 1710 may determine whether to apply the nth power control offset based on the received signal strength packet and the received power packet (S1720). N in S1720 may be a natural number greater than 2. When the n-th power control offset is applied, the wireless power transmitter 1710 may adjust the transmission power by applying the n-th power control offset value to the control error value of the received control error packet (S1721). More specifically, applying the n th power control offset may be weighting the n th power control offset value while the first to n th power control offsets are applied. For example, if the first power control offset value is +10 and the second to nth power control offset values are +5, the value applied to the control error value by applying the power control offset is 10 + 5 * (n-1 May be).

The electronic device 1730 may consume energy charged in the battery as power due to a predetermined event (S1722). Like S1705, S1711, and S1717, the electronic device 1730 may perform a specific operation of consuming power when the charging rate of the battery reaches a predetermined reference value. The difference from S1705, S1711, and S1717 is that the wireless power transmitter 1710 is transmitting transmission power by applying the nth power control offset. Thus, the battery may be larger than the consumed power consumption of the received transmission power so that the battery can be charged normally.

The wireless power transmitter 1710 may receive a received power packet (RPP) (S1712). That is, during the application of the nth power control offset, the wireless power transmitter 1710 may receive a received power packet (RPP).

The wireless power transmitter 1710 may determine whether to release the power control offset based on the received received power packet and perform the release of the power control offset (S1724). When the application of the power control offset is released, the wireless power transmitter 1710 may adjust the transmission power according to the control error value of the received control error packet (S1724).

The wireless power receiver 1720 may terminate trickle charging when the battery charge rate is greater than or equal to a predetermined reference value (not shown). The wireless power receiver 1720 may control the charging power to receive the guaranteed power according to the power transmission contract when the trickle charge ends.

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

Referring to FIG. 18, when the wireless power transmitter enters a power transmission step, the wireless power transmitter may receive a control error packet (S1801). Although not shown, the wireless power receiver may set a control error value of the control error packet according to the battery charge rate and transmit the control error value to the wireless power transmitter. More specifically, the wireless power receiver may perform trickle charging when the charging rate at which the battery is fully discharged is 0% or close to 0%. For trickle charging, the wireless power receiver may determine a control error value to transmit charging power lower than the guaranteed power of the power transmission contract. For example, the control error value may be a negative value.

The wireless power transmitter may adjust the transmission power according to the control error value of the received control error packet (S1802). The wireless power transmitter may reduce the intensity of the transmission power when the control error value of the received control error packet is negative. In addition, the wireless power transmitter may adjust the degree of reduction of the transmission power according to the negative level of the control error value.

The wireless power transmitter may receive the received power packet (S1803). More specifically, the wireless power transmitter may receive the received power packet at a predetermined cycle. The received power packet may include a received power value that is information on the strength of the received power received by the wireless power receiver.

The wireless power transmitter may receive the signal strength packet (S1804). Without being limited thereto, the wireless power transmitter may receive one of a signal strength packet transmitted in the ping step, a configuration packet transmitted in the configuration and identification step, and an identification packet.

Upon reception of the signal strength packet, the wireless power transmitter may determine whether to apply an nth (n is a natural number) power control offset (S1805). In this case, the wireless power transmitter may determine whether the received power is less than or equal to the first threshold power (S1806). When the wireless power transmitter receives a signal strength packet not received in the power transmission step, the wireless power transmitter may determine whether to apply the nth power control offset. The first threshold power may be a received power value that is insufficient for the battery to be charged due to power consumption due to a predetermined event during wireless charging. In addition, the first threshold power may be a preset power value. In addition, the first threshold power may be 1,500 mW or less. More specifically, the first threshold power may be 1,100 mW. Although not limited thereto, a first threshold voltage or a first threshold current may be used instead of the first threshold power to determine whether the n th power control offset is applied. Also, although not shown, the determination of whether to apply the n-th power control offset may further include determining information on the wireless power receiver of the received identification packet or configuration packet. The wireless power transmitter may not need to apply the n th power control offset according to the unique information of the wireless power receiver. In this case, the wireless power transmitter may selectively determine whether to apply the n-th power control offset. In addition, although not shown, determining whether to apply the nth power control offset may further include determining a type of a wireless power transmission procedure of a supported standard of the wireless power transmitter and the wireless power receiver. The wireless power transmitter may not need to apply the n th power control offset according to the version information of the WPC standard. In this case, the wireless power transmitter may selectively determine whether to apply the n-th power control offset.

If the received power is less than or equal to the first threshold power, the wireless power transmitter may start applying the nth (n is a natural number) power control offset (S1807). That is, the wireless power transmitter may determine that the strength of the transmit power for charging the battery is insufficient and apply the n th power control offset.

In addition, when the received power exceeds the first threshold power, the wireless power transmitter determines that the strength of the transmit power for charging the battery is sufficient, and sets the n-th power control offset to the control error value of the control error packet provided by the wireless power transmitter. Output power can be controlled without application. That is, in this case, the process returns to S1801 from S1806.

During the application of the n th power control offset, the wireless power transmitter may receive a control error packet (S1808). The control error packet may include a control error value that is a negative value for trickle charge.

During the application of the n th power control offset, the wireless power transmitter may adjust the transmission power by applying the n th power control offset to the control error value of the control error packet (S1809). The application of the n th power control offset may be that the wireless power transmitter adds the n th power control offset value to the control error value of the control error packet. More specifically, the wireless power transmitter may adjust the output power by increasing the control error value by a positive n-th power control offset value to a negative control error value. In addition, the offset value of the first power control offset may be different from the power control offset value of the second to n-th power control offset. For example, the power control offset value of the first power control offset may be greater than the power control offset value of the second to nth power control offset. The reason why the first power control offset value is larger than the second to nth power control offset is that the initial power control offset value is a relatively high value in order to reduce the power control offset application time. The reason why the second to nth power control offset values are smaller than the value of the first power control offset is to protect the battery during power control offset application. For example, the first power control offset value may be +10 and the second to nth power control offset values may be +5. In addition, applying the n th power control offset may be to weight the n th power control offset value to the n th power control offset value while the n th power control offset is applied. In addition, the wireless power transmitter may gradually apply a power control offset. For example, when the first power control offset value is +10 and the second power control offset value is +5, the value applied to the control error value by applying the power control offset may be +15. In addition, the n-th power control offset application may add a value obtained by accumulating the first to n-th power control offset values to the control error value of the control error packet. As an example of applying the n th power control offset, the control error value of the control error packet may be -100, which is a negative integer, and the n th power control offset value may be 10 + 5 * (n-1), which is a positive integer. In this case, the wireless power transmitter may adjust the output power by setting the power control value to (-100 + 10 + 5 * (n-1)) by adding a power control offset value to a control error value other than a control error value of -100. . Therefore, the wireless power transmitter according to another embodiment may control the charging power by applying the nth power control offset. In addition, the wireless power transmitter according to another embodiment may charge the fully discharged battery by controlling the charging power by applying the n-th power control offset. In addition, the wireless power transmitter according to another embodiment may increase the transmission power by applying the n-th power control offset, thereby increasing the wireless charging speed. In addition, the wireless power transmitter according to another embodiment may protect the battery by gradually applying the n-th power control offset value.

During the nth power control offset application, the wireless power transmitter may receive a received power packet in operation S1810.

During application of the nth power control offset, the wireless power transmitter may determine whether a signal strength packet is received (S1811). The wireless power transmitter may return to S1805 when receiving the signal strength packet. That is, when the wireless power transmitter receives the signal strength packet, the wireless power transmitter determines that the wireless power receiver does not receive sufficient power for charging the battery. Without being limited thereto, the wireless power transmitter may receive one of a signal strength packet transmitted in the ping step, a configuration packet transmitted in the configuration and identification step, and an identification packet.

During the application of the n th power control offset, the wireless power transmitter may determine whether the received power of the received power packet is greater than or equal to the second threshold power in order to determine whether to release the power control offset (S1812). The second threshold power may be a reception power value in which the charging power of the battery is higher than that of the battery. The second threshold power may be greater than the first threshold power. In addition, the second threshold power may be a preset power value. In addition, the second threshold power may be 2,500 mW or more. More specifically, the second threshold power may be 4,500 mW.

If the received power is greater than or equal to the second threshold power, the wireless power transmitter may release the application of the power control offset (S1813). That is, the wireless power transmitter may determine that the strength of the transmit power for charging the battery is sufficient to release the application of the power control offset. In this case, the wireless power transmitter may control the transmission power without applying the power control offset to the control error value of the control error packet provided by the wireless power receiver. In addition, when the received power is less than the second threshold power, the wireless power transmitter may determine that the strength of the transmit power for charging the battery is still insufficient, and may proceed to step S1808. In this case, the wireless power transmitter continues to apply the nth power control offset.

19 is a diagram for describing a wireless charging method on a wireless charging system, according to another embodiment.

In detail, FIG. 19 is a flowchart for describing a procedure of performing a power control offset on a wireless charging system.

19 does not show an electronic device. The electronic device may follow the operations of the electronic device of FIGS. 15 and 17. The battery of the electronic device may be discharged before the wireless charging starts (not shown). More specifically, the battery may be in a fully discharged state. The battery is not limited thereto, and the battery may be below a predetermined charge rate.

In addition, after the battery is discharged, the wireless charging may be started to follow the wireless power transmission procedure in order of selection, ping, identification and configuration, and power transmission (not shown).

The wireless power receiver 1920 may start trickle charging after the transition to the power transmission step in the identification and configuration step (S1901). More specifically, the wireless power receiver 1920 may perform trickle charging according to the state of charge of the battery. The trickle charging may be performed by the wireless power receiver 1920 when the battery is fully discharged or when the battery is below a predetermined charge rate. The wireless power receiver 1920 may control the charging power transmitted from the wireless power transmitter 1910 by a control error packet (CEP) for trickle charging.

The wireless power transmitter 1910 may receive the control error packet CEP from the wireless power receiver 1920 (S1902). The wireless power receiver 1920 may adjust the strength of the transmission power based on the control error value of the received control error packet (CEP). More specifically, the control error value of the control error packet (CEP) transmitted for trickle charging may be a negative value. The wireless power transmitter 1910 may reduce the strength of the transmission power based on a control error value that is a negative value. In addition, the wireless power transmitter 1710 may continuously receive a control error packet (CEP) (not shown). The control error values of consecutively received control error packets (CEPs) may all be negative for trickle charging of the wireless power receiver 1920.

The wireless power transmitter 1910 may receive a received power packet (RPP) (S1903). The wireless power transmitter 1910 may determine the strength of the charging power currently being received by the wireless power receiver 1920 by the received power packet RRP. The wireless power transmitter 1910 may receive a received power packet (RPP) during trickle charging of the wireless power receiver.

The wireless power transmitter 1910 may receive a signal strength packet (S1904) (S1904). The electronic device consumes energy charged in the battery as power due to a predetermined event, and the battery may be discharged. The predetermined event may mean that the charging rate of the battery reaches a predetermined reference value and the booting of the system of the electronic device or the operation of the screen screen is performed. The battery discharge may be a momentary full discharge state of a battery due to a predetermined event or a state in which charging power for battery charging is insufficient. In addition, the wireless power receiver 1920 determines that power transmission is interrupted because the received power is below a predetermined reference value, and thus transmits a signal strength packet. Without being limited to the signal strength packet, the wireless power transmitter 1910 may receive any one of a signal strength packet, a configuration packet, and an identification packet.

Upon receiving the signal strength packet, the wireless power transmitter 1910 may stop power transmission (S1905). In this case, the wireless power transmitter 1910 may store information about the signal strength packet and the received power packet in a storage unit. Thereafter, the wireless power transmitter 1910 may proceed with the wireless power transmission procedure in order of selection, ping, identification and configuration, and power transmission.

The wireless power transmitter 1910 may determine whether to apply the first power control offset based on the stored signal strength packet and the received power packet (S1906). The wireless power receiver 1920 may start trickle charging (S1907). When the first power control offset is applied, the wireless power transmitter 1910 may adjust the transmission power by applying the first power control offset value to the control error value of the received control error packet (S1908). Therefore, the wireless power transmitter 1910 controls the charging power by applying the first power control offset. Whether the first to n th power control offsets and the first to n th power control offsets of the wireless power transmitter 1910 are applied to the wireless charging method in the wireless power transmitter according to another embodiment of FIG. 20 to be described later. Explain in detail.

The wireless power transmitter 1910 may receive a received power packet (RPP) (S1909). That is, during the application of the first power control offset, the wireless power transmitter 1910 may receive a received power packet (RPP).

The wireless power transmitter 1910 may receive a signal strength packet (SS) (S1910). The electronic device consumes energy charged in the battery as power due to a predetermined event, and the battery may be discharged. For example, even if the wireless power transmitter transmits the transmission power by applying the first power control offset, the battery consumes more power than the received power because the power consumption due to the predetermined event is greater than the reception power. Charging power may be insufficient. In addition, the wireless power receiver 1920 determines that power transmission is interrupted because the received power is below a predetermined reference value, and thus transmits a signal strength packet. Without being limited to the signal strength packet, the wireless power transmitter 1910 may receive any one of a signal strength packet, a configuration packet, and an identification packet.

When the signal strength packet is received during the application of the first power control offset, the wireless power transmitter 1910 may stop power transmission (S1911). In this case, the wireless power transmitter 1910 may store information about the signal strength packet and the received power packet in a storage unit. Thereafter, the wireless power transmitter 1910 may proceed with the wireless power transmission procedure in order of selection, ping, identification and configuration, and power transmission.

The wireless power transmitter 1910 may determine whether to apply the nth power control offset based on the received signal strength packet and the received power packet in operation S1912. N in S1912 may be two or more natural numbers. The wireless power receiver 1920 may start trickle charging (S1913). When the n-th power control offset is applied, the wireless power transmitter 1910 may adjust the transmission power by applying the n-th power control offset value to the control error value of the received control error packet (S1914). More specifically, applying the n th power control offset may be weighting the n th power control offset value while the first to n th power control offsets are applied. For example, if the first power control offset value is +10 and the second to nth power control offset values are +5, the value applied to the control error value by applying the power control offset is 10 + 5 * (n-1 May be).

The wireless power transmitter 1910 may receive a received power packet (RPP) (S1915). That is, during the nth power control offset application, the wireless power transmitter 1910 may receive a received power packet (RPP).

The wireless power transmitter 1910 may determine whether to release the power control offset based on the received received power packet and perform the release of the power control offset (S1916). When the application of the power control offset is released, the wireless power transmitter 1910 may adjust the transmission power according to the control error value of the received control error packet (S1917).

The wireless power receiver 1920 may terminate trickle charging when the battery charge rate is greater than or equal to a predetermined reference value (not shown). The wireless power receiver 1920 may control the charging power to receive guaranteed power according to the power transmission contract when terminating the trickle charge.

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

Referring to FIG. 20, when the wireless power transmitter enters a power transmission step, the wireless power transmitter may receive a control error packet (S2001). Although not shown, the wireless power receiver may set a control error value of the control error packet according to the battery charge rate and transmit the control error value to the wireless power transmitter. More specifically, the wireless power receiver may perform trickle charging when the charging rate at which the battery is fully discharged is 0% or close to 0%. For trickle charging, the wireless power receiver may set a control error value to transmit charging power lower than the guaranteed power of the power transmission contract. For example, the control error value may be a negative value.

The wireless power transmitter may adjust the transmission power according to the control error value of the received control error packet (S2002). The wireless power transmitter may reduce the intensity of the transmission power when the control error value of the received control error packet is negative. In addition, the wireless power transmitter may adjust the degree of reduction of the transmission power according to the negative level of the control error value.

The wireless power transmitter may receive the received power packet (S2003). More specifically, the wireless power transmitter may receive the received power packet at a predetermined cycle. The received power packet may include a received power value that is information on the strength of the received power received by the wireless power receiver. In addition, the wireless power transmitter may store information on the received received power packet in a storage unit (not shown).

The wireless power transmitter may receive the signal strength packet (S2004). Without being limited thereto, the wireless power transmitter may receive one of a signal strength packet transmitted in the ping step, a configuration packet transmitted in the configuration and identification step, and an identification packet. In addition, when the wireless power transmitter receives the signal strength packet in the power transmission step, the wireless power transmitter may store information about the received signal strength packet in a storage unit (not shown).

Upon receiving the signal strength packet, the wireless power transmitter may stop power transmission (S2005). 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.

After the transition to the power transmission step, the wireless power transmitter may determine whether to apply the nth (n is a natural number) power control offset (S2005). In this case, the wireless power transmitter may determine whether the received power is less than or equal to the first threshold power (S2006). The first threshold power may be a received power value that is insufficient for the battery to be charged due to power consumption due to a predetermined event during wireless charging. In addition, the first threshold power may be a preset power value. In addition, the first threshold power may be 1,500 mW or less. More specifically, the first threshold power may be 1,100 mW. Although not limited thereto, a first threshold voltage or a first threshold current may be used instead of the first threshold power to determine whether the n th power control offset is applied. Also, although not shown, the determination of whether to apply the n-th power control offset may further include determining information on the wireless power receiver of the received identification packet or configuration packet. The wireless power transmitter may not need to apply the n th power control offset according to the unique information of the wireless power receiver. In this case, the wireless power transmitter may selectively determine whether to apply the n-th power control offset. In addition, although not shown, determining whether to apply the nth power control offset may further include determining a type of a wireless power transmission procedure of a supported standard of the wireless power transmitter and the wireless power receiver. The wireless power transmitter may not need to apply the n th power control offset according to the version information of the WPC standard. In this case, the wireless power transmitter may selectively determine whether to apply the n-th power control offset.

If the received power is less than or equal to the first threshold power, the wireless power transmitter may initiate application of the nth (n is a natural number) power control offset (S2008). That is, the wireless power transmitter may determine that the strength of the transmit power for charging the battery is insufficient and apply the n th power control offset.

In addition, when the received power exceeds the first threshold power, the wireless power transmitter determines that the strength of the transmit power for charging the battery is sufficient, and sets the n-th power control offset to the control error value of the control error packet provided by the wireless power transmitter. Output power can be controlled without application. That is, in this case, the process returns to S2005 from S2007.

During the application of the n th power control offset, the wireless power transmitter may receive a control error packet (S2009). The control error packet may include a control error value that is a negative value for trickle charge.

During the application of the n th power control offset, the wireless power transmitter may adjust the transmission power by applying the n th power control offset to the control error value of the control error packet (S2010). The application of the n th power control offset may be that the wireless power transmitter adds the n th power control offset value to the control error value of the control error packet. More specifically, the wireless power transmitter may adjust the output power by increasing the control error value by a positive n-th power control offset value to a negative control error value. In addition, the offset value of the first power control offset may be different from the power control offset value of the second to n-th power control offset. For example, the power control offset value of the first power control offset may be greater than the power control offset value of the second to nth power control offset. The reason why the first power control offset value is larger than the second to nth power control offset is that the initial power control offset value is a relatively high value in order to reduce the power control offset application time. The reason why the second to nth power control offset values are smaller than the value of the first power control offset is to protect the battery during power control offset application. For example, the first power control offset value may be +10 and the second to nth power control offset values may be +5. In addition, applying the n th power control offset may be to weight the n th power control offset value to the n th power control offset value while the n th power control offset is applied. In addition, the wireless power transmitter may gradually apply a power control offset. For example, when the first power control offset value is +10 and the second power control offset value is +5, the value applied to the control error value by applying the power control offset may be +15. In addition, the n-th power control offset application may add a value obtained by accumulating the first to n-th power control offset values to the control error value of the control error packet. As an example of applying the n th power control offset, the control error value of the control error packet may be -100, which is a negative integer, and the n th power control offset value may be 10 + 5 * (n-1), which is a positive integer. In this case, the wireless power transmitter may adjust the output power by setting the power control value to (-100 + 10 + 5 * (n-1)) by adding a power control offset value to a control error value other than a control error value of -100. . Therefore, the wireless power transmitter according to another embodiment may control the charging power by applying the nth power control offset. In addition, the wireless power transmitter according to another embodiment may charge the fully discharged battery by controlling the charging power by applying the n-th power control offset. In addition, the wireless power transmitter according to another embodiment may increase the transmission power by applying the n-th power control offset, thereby increasing the wireless charging speed. In addition, the wireless power transmitter according to another embodiment may protect the battery by gradually applying the n-th power control offset value.

During the application of the n th power control offset, the wireless power transmitter may receive the received power packet (S2011). In this case, the wireless power transmitter may store information of the received received power packet in a storage unit (not shown).

During the application of the n-th power control offset, the wireless power transmitter may determine whether a signal strength packet is received (S2012). The wireless power transmitter may return to S2005 upon receiving the signal strength packet. That is, when the wireless power transmitter receives the signal strength packet, the wireless power transmitter determines that the wireless power receiver does not receive sufficient power for charging the battery. Without being limited thereto, the wireless power transmitter may receive one of a signal strength packet transmitted in the ping step, a configuration packet transmitted in the configuration and identification step, and an identification packet.

During the application of the nth power control offset, the wireless power transmitter may determine whether the received power of the received power packet is greater than or equal to the second threshold power in order to determine whether to release the power control offset (S2013). The second threshold power may be a reception power value in which the charging power of the battery is higher than that of the battery. The second threshold power may be greater than the first threshold power. In addition, the second threshold power may be a preset power value. In addition, the second threshold power may be 2,500 mW or more. More specifically, the second threshold power may be 4,500 mW.

If the received power is greater than or equal to the second threshold power, the wireless power transmitter may release the application of the power control offset (S2014). That is, the wireless power transmitter may determine that the strength of the transmit power for charging the battery is sufficient to release the application of the power control offset. In this case, the wireless power transmitter may control the transmission power without applying the power control offset to the control error value of the control error packet provided by the wireless power receiver. In addition, if the received power is less than the second threshold power, the wireless power transmitter may determine that the strength of the transmit power for charging the battery is still insufficient, and may transition to step S2009. In this case, the wireless power transmitter continues to apply the nth power control offset.

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 (19)

A wireless charging method in a wireless power transmitter for wirelessly transmitting power to a wireless power receiver, Receiving a control error packet in a power transmission step; Adjusting outgoing power according to a control error value of the received control error packet; Receiving a received power packet; Receiving a signal strength packet; And And determining whether to apply a power control offset. According to claim 1, The adjusting of the transmission power according to the control error value of the received control error packet may include: reducing the transmission power if the control error value is negative and increasing the transmission power if the control error value is positive. Charging method. The method of claim 2, And a control error value of the control error packet is negative. The method of claim 3, wherein The determining of whether to apply the power control offset, wireless charging method to determine to apply the power control offset if the received power value of the received power packet is less than the first threshold power. The method of claim 4, wherein The first threshold power is less than 1,500mW wireless charging method. The method of claim 4, wherein Initiating application of a power control offset; Receiving a control error packet during application of the power control offset; And And adjusting the outgoing power by applying the power control offset to a control error value of the received control error packet during the application of the power control offset. The method of claim 6, Adjusting the transmission power by applying the power control offset to the control error value of the control error packet, And a power control offset value added to the control error value to control transmission power. The method of claim 6, Receiving a received power packet during application of the power control offset; And Determining whether to release the power control offset; Determining whether or not to apply the power control offset, If the received power of the received received power packet is greater than or equal to a second threshold power, it is determined to cancel the application of the power control offset, And the second threshold power is greater than the first threshold power. The method of claim 8, The second threshold power is more than 2,500mW wireless charging method. The method of claim 8, And adjusting the outgoing power according to a control error value of the received control error packet after releasing the power control offset. The method of claim 6, Determining whether a signal strength packet is received during the application of the power control offset; Determining whether to apply n-th (n is a natural number of 2 or more) power control offset when receiving the signal strength packet during the application of the power control offset; Initiating said nth power control offset application; Receiving a control error packet during application of the nth power control offset; And Adjusting the outgoing power by applying the n th power control offset to a control error value of the received control error packet during the application of the n th power control offset; The determining of whether to apply the n-th power control offset, When the received power value of the received received power packet is equal to or less than a first threshold power, it is determined to apply the nth power control offset. Adjusting the outgoing power by applying the n-th power control offset to the control error value of the received control error packet during the application of the n-th power control offset, And controlling the output power by adding the accumulated value of the first to nth power control offset values to the received control error value during the application of the nth power control offset. The method of claim 11, wherein And the power control offset value is greater than the nth power control offset value. According to claim 1, Receiving the control error packet in the power transmission step, A wireless charging method for continuously receiving a control error packet having a negative control error value. The method of claim 3, wherein Determining whether the power control offset is applied, Using the identification packet information received from the wireless power receiver, The wireless power transmitter, And selectively applying the power control offset according to the identification packet information. A wireless charging method in a wireless power transmitter for wirelessly transmitting power to a wireless power receiver, Receiving a control error packet in a power transmission step; Adjusting outgoing power according to a control error value of the received control error packet; Receiving a received power packet; Receiving a signal strength packet; Stopping power transmission; And determining whether to apply an nth (n is a natural number) power control offset after the transition to the power transfer step. The method of claim 15, Initiating application of the nth power control offset; Receiving a control error packet during application of the nth power control offset; And And adjusting the outgoing power by applying the n th power control offset to a control error value of the received control error packet during the application of the n th power control offset. The method of claim 16, Determining whether a signal strength packet is received during the application of the nth power control offset; When the signal strength packet is received during the application of the nth power control offset, stopping the power transmission; Determining whether to apply an n + 1th power control offset after the transition to the power transmission step; Initiating application of the n + 1 power control offset; Receiving a control error packet during application of the n + 1 power control offset; And Adjusting the outgoing power by applying the n + 1 power control offset to a control error value of the received control error packet during the application of the n + 1 power control offset; The determining of whether the n + 1 power control offset is applied may include: When the received power value of the received received power packet is less than or equal to a first threshold power, it is determined to apply the n + 1 power control offset. During the application of the n + 1 th power control offset, adjusting the outgoing power by applying the n + 1 th power control offset to a control error value of the received control error packet, And controlling the output power by adding a accumulated value of first to n + 1th power control offset values to the received control error value during the application of the n + 1th power control offset. The method of claim 6, Receiving a received power packet during application of the nth power control offset; And Determining whether to release the power control offset; Determining whether or not to apply the power control offset, If the received power of the received received power packet is greater than or equal to a second threshold power, it is determined to cancel the application of the power control offset, And the second threshold power is greater than the first threshold power. The method of claim 18, And adjusting the outgoing power according to a control error value of the received control error packet after releasing the power control offset.

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