Wireless power transmission control method and device

Abstract

To provide a wireless power transmission control method and a device capable of preventing unnecessary interruption of charging by minimizing foreign object detection errors.SOLUTION: A method includes: a first packet receiving step of receiving a foreign object detection status packet; a first determination step of determining whether a foreign object is present based on the foreign object detection status packet; and a power control step of controlling power based on a determination result of the first determination step. The power control step includes a first power transmission mode in which a first power is transmitted when it is determined that there is a foreign object as a result of the determination in the first determination step, and a second power transmission mode in which a second power is transmitted when it is determined that there is no foreign object as a result of the determination in the first determination step.SELECTED DRAWING: Figure 12

Description

[Technical field]

[0001] The present invention relates to a wireless power transmission technology, and more particularly to a wireless power transmission control method for wireless charging. and relating to the device. [Background technology]

[0002] Recently, with the rapid development of information and communication technology, ubiquitous society based on information and communication technology has become a reality. It is becoming a meeting.

[0003] In order for information and communication devices to be connected anytime and anywhere, all facilities in society need to be equipped with communication capabilities. A sensor with a built-in computer chip with As a result, the power supply for these devices and sensors is becoming a new issue. as well as Bluetooth handsets and music players such as iPods As the variety of portable devices such as these rapidly increases, the task of charging the batteries becomes more and more time-consuming for users. This has required a lot of time and effort. The technology has recently attracted interest.

[0004] Wireless power transmission technology wireless energy transfer) is a technology that uses the principle of magnetic field induction to It is a technology that transmits electrical energy from a transmitter to a receiver by using a wire. Electric motors and transformers using the principle of magnetic induction were first used, followed by high frequency and Micro We are also trying to transmit electrical energy by emitting electromagnetic waves such as owave and laser. The electric toothbrushes and some wireless razors that we use often are actually charged by the electromagnetic induction principle. Be electrified.

[0005] So far, the only wireless energy transmission methods are magnetic induction and magnetic resonance. romagnetic resonance (ROMR) method and short wavelength radio frequency F transmission method.

[0006] In the magnetic induction method, two coils are placed next to each other, and when a current is passed through one coil, The magnetic flux generated at this time induces an electromotive force in other coils. This technology is being rapidly commercialized, especially for small devices such as mobile phones. The air induction method can transmit up to several hundred kilowatts (kW) of power and is highly efficient, but The maximum transmission distance is less than 1 centimeter (cm), so it is generally placed next to the charger or the bottom. There are some shortcomings that must be addressed.

[0007] The magnetic resonance method is characterized by using electric and magnetic fields instead of electromagnetic waves and currents. The magnetic resonance method is hardly affected by electromagnetic waves, so it is safe for other electronic devices and the human body. On the other hand, it can only be used in a limited distance and space. However, the energy transfer efficiency is somewhat low.

[0008] Short-wavelength wireless power transmission - simply, RF transmission - is a method of transmitting energy by radio waves (Radi This technology takes advantage of the fact that radio waves can be transmitted and received directly in the form of radio waves. A RF wireless power transmission method using a rectenna. is a compound word of antenna and rectifier, and is used for RF power. It means an element that converts AC radio waves directly into DC power. This is a technology that converts the material into a liquid and uses it in a chemical reaction. Recently, the efficiency has improved, and research into commercialization is active. is progressing.

[0009] Wireless power transmission technology is not only used in mobile devices, but also in a wide range of industries, including IT, railways, and home appliances. It can be utilized for.

[0010] There is no conductor that is not a wireless power receiver in the wireless charging area, i.e., a foreign object (FO). When an ign Object (FO) is present, the FO contains electromagnetic waves emitted from the wireless power transmitter. As an example, FO can be used with coins, paperclips, pins, buttons, etc. It may contain pens, etc.

[0011] If there is an FO between the wireless power receiver and the wireless power transmitter, the wireless charging efficiency will be significantly reduced. Not only does the temperature drop significantly, but the rise in ambient temperature due to FO also reduces the power consumption of the wireless power receiver and the wireless power transmitter. If the FO located in the charging area is not removed, the power Not only does this result in waste, but overheating can also damage the wireless power transmitter and receiver. May cause injury.

[0012] In addition, even if there is no FO in the charging area, the wireless power transmitter may be in the charging area. If it mistakenly determines that a foreign object is present, charging may be interrupted.

[0013] Therefore, it is important in the field of wireless charging technology to accurately detect FOs located in the charging area. This has emerged as a major issue. Summary of the Invention [Problem to be solved by the invention]

[0014] The present invention has been devised to solve the above-mentioned problems of the prior art. The present invention provides a method and device for controlling wireless power transmission for wireless charging.

[0015] Another object of the present invention is to provide a wireless power transmitter capable of detecting a foreign object more accurately. This is what we should do.

[0016] It is still another object of the present invention to prevent unnecessary charging by minimizing foreign object detection errors. An object of the present invention is to provide a wireless power transmission control method and device capable of preventing interruptions in advance.

[0017] It is still another object of the present invention to prevent damage to equipment caused by foreign objects and to provide a method for detecting the presence or absence of foreign objects. Providing a wireless power transmitter that enables uninterrupted charging through adaptive transmission power control To do so.

[0018] The technical problems to be solved by the present invention are not limited to the above-mentioned technical problems. Further technical problems that have not been solved will become apparent from the following description by those skilled in the art to which the present invention pertains. This will be clearly understood by those who have [Means for solving the problem]

[0019] The present invention can provide a wireless power transmission control method and an apparatus therefor.

[0020] A method for controlling wireless power transmission of a wireless power transmitter according to an embodiment of the present invention includes: a first packet receiving step of receiving a packet containing a foreign object detection status packet; A first determination step for determining whether or not the power is supplied to the power supply 100 is performed, and power is controlled based on the result of the determination step. The power control step includes: determining that a foreign object is present as a result of the first determining step; A first power transmission mode in which the first power is transmitted if a foreign object is detected as a result of the first determination step. The second power transmission mode may include transmitting a second power when it is determined that there is no power.

[0021] Here, the second power is greater than the first power, and power is transmitted in the second power transmission mode. The power is increased or decreased between the first power and the second power based on changes in the environment. It can be transmitted.

[0022] Here, the first power may be 5W.

[0023] The second power may be 15W.

[0024] The wireless power transmission control method further includes determining whether or not a foreign object is present in the first power transmission mode. This may include a second judgment step of:

[0025] The second determining step further includes a third step of determining whether or not a foreign object is present based on a transmission power loss. and a fourth judgment step of judging whether or not a foreign object is present based on a temperature change. It may also include one.

[0026] Here, the third determination step includes a step of measuring the strength of the transmission power and a step of determining a strength of the transmission power corresponding to the transmission power. receiving information about a strength of a received power from a wireless power receiver; and estimating a power loss based on a difference between the received power strength and the received power strength; and The step of comparing the measured power loss with a predetermined power loss reference value to determine whether or not a foreign object is present. It is possible to do so.

[0027] The fourth determination step includes measuring a temperature in the charging area and determining whether or not the charging area is in a charging state based on the measured temperature. calculating a temperature change for a certain period of time based on the calculated temperature change and a temperature change standard; A step of comparing the values ​​to determine whether or not a foreign object is present can be included.

[0028] Also, if it is determined in the second determining step that a foreign object is present, the power transmission is interrupted. If it is determined that there is no foreign object as a result of the second determination step, the first power transmission mode is switched to the to the second power transfer mode.

[0029] According to another embodiment of the present invention, a method for controlling wireless power transmission of a wireless power transmitter includes: a first packet receiving step of receiving a packet and detecting the presence of a foreign object based on the foreign object detection status packet; A first determination step for determining whether a foreign object is present or not and a second determination step for determining whether a foreign object is present or not. If the first power is transmitted, it is determined that no foreign object is present in the first determining step. transmitting a power between the first power and the second power and transmitting the first power. and a second determination step of determining whether or not a foreign object is present, the second determination step being based on a transmission power loss. The third judgment step is to judge the presence or absence of a foreign object based on the temperature change. The method may include at least one of a fourth judgment step for judging nothing.

[0030] A wireless power transmitter according to still another embodiment of the present invention includes an antenna for transmitting wireless power and a front end. a demodulator for demodulating a signal including a foreign object detection status packet received from the antenna; a controller that determines whether a foreign object is present based on the foreign object detection status packet, If the result of the first determination is that a foreign object is present, the first power If it is determined that there is no foreign object in the first determination step, The power transmitted can be controlled to be between the first power and the second power.

[0031] Also, the controller determines that there is a foreign object as a result of the first determination and, during the first power transmission, A secondary judgment can be made as to whether or not a foreign object is present.

[0032] Here, the second judgment is a third judgment that judges whether or not a foreign object exists based on the transmission power loss. and a fourth judgment based on temperature change to judge whether or not a foreign object is present. It is possible.

[0033] The wireless power transmitter also includes a sensor for measuring the strength of the transmission power and transmitting the measured strength to the controller. and wherein in the third determination, the controller determines a strength of a received power corresponding to the transmission power. and receiving information through the demodulator, and calculating a difference between the intensity of the transmission power and the intensity of the reception power. and estimating a power loss based on the estimated power loss and a predetermined power loss criterion for a certain period of time. The standard values ​​can be compared to determine whether or not a foreign object is present.

[0034] In addition, the sensor measures the temperature and transmits the temperature to the controller. calculates a temperature change over a certain period of time based on the measured temperature, and the calculated temperature The change can be compared with a predetermined temperature change reference value to determine whether or not a foreign object is present.

[0035] In addition, when the controller determines that there is a foreign object as a result of the second determining step, If it is determined that there is no foreign object as a result of the second determination step, the first power is supplied to the The power can be controlled so that power between the first power and the second power is transmitted.

[0036] Also, the second power may be greater than the first power, and the first power may be 5W.

[0037] According to still another embodiment of the present invention, a method for controlling wireless power transmission in a wireless power transmitter includes detecting a foreign object. a first packet receiving step of receiving an outgoing status packet and A first determination step for determining whether a foreign object is present or not, and a power supply control step for controlling a power supply based on a result of the first determination step The first power adjusting stage may include adjusting

[0038] Here, the first power adjustment step

[0039] If the first determination step determines that no foreign object is present, the guaranteed power is set to the second power, which is the initial setting. and maintaining the guaranteed power at the second level if it is determined in the first determining step that a foreign object is present. The step of adjusting the power down from the first power to the second power can be included.

[0040] Additionally, the first power may be 5W or less.

[0041] Additionally, the second power may be 15W or less.

[0042] The wireless power transmission control method further includes a step of performing charging based on the adjusted power. The power transmission step and the power transmission step further include a second determination step for determining whether or not a foreign object is present. It is possible.

[0043] Here, the second judgment step is

[0044] A third determination step of determining whether or not a foreign object is present based on the estimated power loss during the charging. If the third determination step determines that a foreign object is present, the charging being performed is interrupted. obtain.

[0045] Here, the third judgment step is

[0046] measuring a strength of a transmission power during charging and a strength of a reception power corresponding to the transmission power; receiving information on the strength of the pre-transmission power and the strength of the received power from a wireless power receiver; and estimating a power loss based on a difference value of the estimated power loss and a desired power loss for a certain period of time. The step of comparing the power loss to a certain reference value to determine whether a foreign object is present can be included.

[0047] Also, the second judgment step

[0048] a fourth determination step of determining whether or not a foreign object is present based on a temperature change during charging; If the fourth determining step determines that a foreign object is present, the ongoing charging may be interrupted.

[0049] Here, the fourth judgment step is

[0050] Measuring the temperature of the charging area and determining a temperature change over a certain period of time based on the temperature measurement result. and comparing the calculated temperature change with a predetermined temperature change reference value to determine whether a foreign object is present. The method may include determining whether or not

[0051] Also, if the result of the determination in the third or fourth determination step is that no foreign object is present, A renegotiation step may further be included in which the power transmission contract is renegotiated to reset the guaranteed power.

[0052] Also, the second judgment step

[0053] A third determination step of determining whether or not a foreign object is present based on the estimated power loss during the charging. If the third determining step determines that a foreign object is present, the charging device determines whether or not a foreign object is present based on a temperature change measured during charging. and a fourth determination step for determining whether or not a foreign object is present in the fourth determination step. If there exists a problem, the power transmission for charging may be interrupted within the predetermined time.

[0054] Also, the wireless power transmission control method includes transmitting a response based on a determination result of the first determination step. the response being a response indicating the presence of a foreign object, If the guaranteed power exceeds the first power, the power intensity is adjusted downward to be equal to or less than the first power. It is possible.

[0055] Here, the first power may be 5W.

[0056] Also, the first judgment step

[0057] A quality factor threshold value is determined based on the reference quality factor value included in the foreign object detection status packet. and comparing a previously measured quality factor value with the quality factor critical value to determine whether or not there is a foreign object. The method may include determining whether or not

[0058] A wireless power transmitter according to another embodiment of the present invention includes a transmission antenna for transmitting wireless power and a front end. a demodulator for demodulating the signal from the transmission antenna and receiving a foreign object detection status packet; a controller that determines whether or not a foreign object is present based on the foreign object detection status packet, and adjusting the intensity of the wireless power based on the result of the determination as to whether or not the foreign object is present. This can be done.

[0059] If the controller determines that no foreign object is present, the guaranteed power is set to the second initial setting. If it is determined that a foreign object is present, the guaranteed power is changed from the second power to the first power. can be adjusted downwards.

[0060] Here, the first power may be 5W or less.

[0061] In addition, the controller detects the presence or absence of a foreign object during charging with the adjusted wireless power intensity. Additional decisions can be made.

[0062] In one embodiment, the controller detects the presence of a foreign object based on the estimated power loss during charging. and determining whether or not a foreign object is present based on the power loss, and The power transmission can be interrupted.

[0063] Here, the wireless power transmitter transmits information about the strength of the transmission power to the controller. The controller further includes a sensor for detecting the intensity of the transmission power and the transmission power during the charging. Based on information regarding the strength of the received power received from the wireless power receiver in response to the transmitted power. A power loss is estimated, and the estimated power loss is compared with a preset power loss reference value. By comparing the two, it is possible to determine whether or not a foreign object is present.

[0064] In another aspect, the wireless power transmitter transmits information regarding the measured temperature to the controller. The controller further includes a sensor for transmitting information regarding the measured temperature during the charging. The presence or absence of a foreign object is determined based on a temperature change calculated using the information, and based on the temperature change If a foreign object is detected based on the result of the determination, the power transmission for charging can be interrupted. do.

[0065] In yet another aspect, the controller is configured to: and determining whether or not a foreign object is present, and if a foreign object is present based on the power loss, and determining whether or not a foreign object is present based on the measured temperature change. If a foreign object is present, the power transmission for charging can be interrupted within a predetermined time. Cut.

[0066] If the additional determination result indicates that no foreign object is present, the controller Transmission contracts can be renegotiated to reset guaranteed power.

[0067] The controller determines whether a foreign object is present according to the result of the determination as to whether a foreign object is present. If the currently set guaranteed power exceeds the first power, The power intensity can be adjusted downward below the first power.

[0068] Another embodiment of the present invention is any one of the wireless power transmission control methods. A computer-readable recording medium is provided having a program recorded thereon for executing the method. It is possible.

[0069] The above-mentioned aspects of the present invention are merely a part of the preferred embodiments of the present invention, and the technical features of the present invention are not limited thereto. Various embodiments reflecting the features are described in detail below by those skilled in the art. These and other objects, features and advantages of the present invention will become apparent and will be better understood with reference to the following detailed description of the invention. Effect of the Invention

[0070] The effects of the method, device and system according to the present invention are as follows: be.

[0071] The present invention has an advantage of providing a method and apparatus for controlling wireless power transmission for wireless charging.

[0072] In addition, the present invention provides a wireless power transmitter capable of detecting a foreign object more accurately. There is.

[0073] In addition, the present invention prevents unnecessary interruptions to charging by minimizing foreign object detection errors. It is an advantage to provide a method and apparatus for controlling wireless power transmission that can prevent this.

[0074] In addition, the present invention prevents damage to equipment caused by foreign objects and adaptively controls transmission power depending on the presence or absence of foreign objects. It is an advantage to provide a wireless power transmitter that enables uninterrupted charging through power control. do.

[0075] In addition, the present invention provides a wide range of stable wireless signals depending on the type of receiver and the power transmission environment. It would be advantageous to provide a wireless power transmitter capable of transmitting power.

[0076] The effects obtained from the present invention are not limited to those mentioned above, and may include other effects not mentioned. The effects of the present invention will be clearly understood by those skilled in the art from the following description. It may be possible. [Brief description of the drawings]

[0077] [Figure 1] 1 is a block diagram illustrating a wireless charging system according to an embodiment of the present invention.

[0078] [Diagram 2] FIG. 11 is a block diagram illustrating a wireless charging system according to another embodiment of the present invention.

[0079] [Diagram 3] 4 is a diagram illustrating a sensing signal transmission procedure in a wireless charging system according to an embodiment of the present invention.

[0080] [Figure 4] 1 is a state transition diagram illustrating a wireless power transmission procedure according to an embodiment of the present invention.

[0081] [Diagram 5] 10 is a flowchart illustrating a foreign object detection procedure in a wireless power transmission system according to an embodiment of the present invention.

[0082] [Figure 6] 1 is a block diagram illustrating a structure of a wireless power transmission device according to an embodiment of the present invention.

[0083] [Figure 7] 7 is a diagram illustrating a configuration of the transmission antenna of FIG. 6 according to an embodiment of the present invention.

[0084] [Figure 8] 7 is a block diagram illustrating a structure of a wireless power receiving apparatus that operates in conjunction with the wireless power transmitting apparatus shown in FIG. 6 according to an embodiment of the present invention.

[0085] [Figure 9] 1 is a diagram illustrating a method for controlling power transmission depending on whether a foreign object is detected in a wireless power transmitter according to a conventional technique.

[0086] [Figure 10] 2 is a diagram illustrating a packet format according to an embodiment of the present invention;

[0087] [Figure 11] 4 is a flowchart illustrating a power transmission control method in a wireless power transmitter according to an embodiment of the present invention.

[0088] [Figure 12] 11 is a flowchart illustrating a power transmission control method in a wireless power transmitter according to another embodiment of the present invention.

[0089] [Figure 13] 11 is a diagram illustrating a power transmission control method in a wireless power transmitter according to yet another embodiment of the present invention.

[0090] [Figure 14] 11 is a diagram illustrating a power transmission control method in a wireless power transmitter according to yet another embodiment of the present invention.

[0091] [Figure 15] 11 is a diagram illustrating a power transmission control method in a wireless power transmitter according to yet another embodiment of the present invention.

[0092] [Figure 16a] 11 is a flowchart illustrating a method for controlling wireless power transmission by detecting a foreign object when a transmitter and a receiver have the same version.

[0093] [Figure 16b] 10 is a flowchart illustrating a method for controlling wireless power transmission by detecting a foreign object when a transmitter and a receiver have different versions.

[0094] [Figure 16c] 11 is a flowchart illustrating a method for controlling wireless power transmission by detecting a foreign object when a transmitter and a receiver have the same version.

[0095] [Figure 16d] 10 is a flowchart for explaining a method for controlling wireless power transmission by detecting a foreign object when a transmitter has a higher version than a receiver. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0096] A wireless power transmission control method for a wireless power transmitter according to an embodiment of the present invention includes: a first packet receiving step of receiving the foreign object detection status packet and determining whether or not a foreign object is present based on the foreign object detection status packet; A first determination step for determining power and a power control step for controlling power based on a result of the first determination step. The power control step includes a step of: If the first power is transmitted, the first power transmission mode is selected. If the first determination step determines that there is no foreign object, the first power transmission mode is selected. The power transmission mode may include transmitting a second power when it is determined that the second power is transmitted.

[0097] Hereinafter, the present invention will be described in detail with reference to the accompanying drawings, in which: The suffixes "module" and "module" for components used in the following description are used interchangeably. The "part" is given or mixed with other parts with the sole consideration of ease of drafting the specification. They do not have any distinct meanings or roles in themselves.

[0098] In addition, the suffixes "module" and "section" for components used in the following description are hardware. Hardware components - e.g., circuit elements, microprocessors, memory, sensors, etc. However, this is only one embodiment, and some of the functions of the corresponding components may be Or it may be embodied entirely in software.

[0099] In the description of the embodiment, the components formed "above or below" each component are In the case of "above" or "below", the words "above" and "below" mean that the two components are directly connected to each other. The two components are in contact with each other or one or more other components are disposed between the two components. Also, when it is expressed as "upper" or "lower", it means one It can mean not only the upper direction but also the lower direction based on the component.

[0100] In the description of the embodiment, a device equipped with a function of transmitting wireless power in a wireless charging system For convenience of explanation, the device will be referred to as a wireless power transmitter, a wireless power transmission device, a wireless power transmission apparatus, Wireless power transmitter, transmission stage, transmitter, transmitting device, transmitting side, wireless power transmission device, wireless power In addition, the wireless power receiving device will receive wireless power from the wireless power transmitting device. For convenience of explanation, the term "wireless power receiving device" is used to refer to a device having the function of Wireless power receiver, wireless power receiving device, wireless power receiver, receiving terminal, receiving side, receiving device The devices, receivers, etc. may be used in combination.

[0101] The transmitter according to the present invention may be in the form of a pad, a stand, or an AP (Access Point). ) type, small base station type, stand type, ceiling embedded type, wall mounted type, etc. In this case, one transmitter may transmit power to multiple wireless power receiving devices. The transmitter may comprise at least one means for transmitting radio power.

[0102] Here, the wireless power transmission means generates a magnetic field in a power transmission coil and transmits the magnetic field. Electromagnetic induction method that uses the principle of electromagnetic induction to charge the device, where electricity is induced in the receiving coil by sound. Various wireless power transmission standards based on the above may be used. The charging technology standard organization WPC (Wireless Power Consortium) ) Power standards defined by Qi and PMA (Power Matters Alliance) Standard technologies may include, but are not limited to, magnetic induction.

[0103] In addition, a receiver according to an embodiment of the present invention includes at least one wireless power receiving means. The antenna may receive radio power from one or more transmitters.

[0104] The receiver according to the present invention is a mobile phone, a smartphone, art phone, laptop computer , digital broadcasting terminals, PDAs (Personal Digital Assistants) nts), PMP (Portable Multimedia Player), navigation game applications, MP3 players, electric toothbrushes, electronic tags, lighting devices, remote controls, floats, It can be used in small electronic devices such as wearable devices like smart watches. However, the present invention is not limited to this. Any device capable of doing this is acceptable.

[0105] FIG. 1 is a block diagram illustrating a wireless charging system according to an embodiment of the present invention. .

[0106] Referring to FIG. 1, a wireless charging system mainly includes a wireless power transmission stage 1 for wirelessly transmitting power. 0, a wireless power receiving stage 20 for receiving the transmitted power, and a receiving stage 30 for receiving the received power. The electronic device 30 may be configured to receive the signal from the external device 30.

[0107] As an example, the wireless power transmission stage 10 and the wireless power reception stage 20 are used for wireless power transmission. In-band communication is a method of exchanging information using the same frequency band as the It can be carried out.

[0108] In the in-band communication, the power signal 41 sent by the wireless power transmission stage 10 is When received by the wireless power receiving stage 20, the wireless power receiving stage 20 modulates the received power signal and The resulting signal 42 can be transmitted to the wireless power transmission stage 10.

[0109] As another example, the wireless power transmitting stage 10 and the wireless power receiving stage 20 may be used for wireless power transmission. Out-of-band (OOB) is a method of exchanging information using a frequency band different from the operating frequency. In addition, the IEEE 802.11b / g / n communications may be performed in the same band.

[0110] As an example, information exchanged between the wireless power transmitting stage 10 and the wireless power receiving stage 20 may be Control information as well as status information may be included.

[0111] Here, the state information and control information exchanged between the transmitting and receiving stages will be described in the following embodiment. It will become clearer as we go along.

[0112] The in-band and out-of-band communications may provide two-way communication, Other embodiments may provide, without limitation, simplex or half-duplex communication. good.

[0113] As an example, unidirectional communication is when the wireless power receiving stage 20 transmits information only to the wireless power transmitting stage 10. However, the present invention is not limited to this, and the wireless power transmission stage 10 may be a wireless power reception stage 2. It is also possible to transmit information only to 0.

[0114] The half-duplex communication method allows bidirectional communication between the wireless power receiving stage 20 and the wireless power transmitting stage 10. However, they have the characteristic that information can only be transmitted by one device at any one time.

[0115] The wireless power receiving stage 20 according to an embodiment of the present invention acquires various state information of the electronic device 30. Good too.

[0116] As an example, the status information of the electronic device 30 may include current power usage information, identifying the application that is running, information for identifying the battery, CPU usage information, battery charge status information, battery output voltage / current information, etc., which can be obtained from the electronic device 30, but is not limited to this. Any information that can be used to control wireless power may be used.

[0117] In particular, the wireless power transmission stage 10 according to an embodiment of the present invention is configured to indicate whether or not fast charging is supported. The constant packet can be transmitted to the wireless power receiving stage 20 .

[0118] The wireless power receiving stage 20 supports a fast charging mode for the wireless power transmitting stage 10 connected thereto. If it is confirmed that the electronic device 30 is in a state where ...

[0119] The electronic device 30 displays the image through a display means provided therein, which may be a liquid crystal display. It can be used to indicate that fast charging is possible.

[0120] FIG. 2 is a block diagram illustrating a wireless charging system according to another embodiment of the present invention. do.

[0121] As an example, as shown by reference numeral 200a, the wireless power receiving stage 20 may include a plurality of wireless power The wireless power transmission stage 10 may be configured with a plurality of wireless power receiving devices. The wireless charging may be performed by using the same.

[0122] At this time, the wireless power transmitting stage 10 distributes power to the multiple wireless power receiving devices in a time division manner. As another example, the wireless power transmission stage 10 can transmit, but is not limited to, A plurality of wireless power receiving devices are provided using different frequency bands assigned to the respective wireless power receiving devices. The power can be distributed and sent out.

[0123] At this time, the number of wireless power receiving devices that can be connected to one wireless power transmitting stage 10 is Power requirements for each receiving device, battery charge status, power consumption of electronic devices and wireless power transmission The power consumption may be adaptively determined based on at least one of the available power amount of the receiving device.

[0124] As another example, as shown by reference numeral 200b, the wireless power transmission stage 10 may include a plurality of It may be constituted by a line power transmission device.

[0125] In this case, the wireless power receiving stage 20 can be connected to multiple wireless power transmitting devices at the same time. The charging device may simultaneously receive power from the wireless power transmitter and perform charging.

[0126] At this time, the number of wireless power transmitters connected to the wireless power receiver 20 is 2. 0 power requirements, battery charge status, power consumption of electronic devices, use of wireless power transmitters It can be adaptively determined based on the amount of available power, etc.

[0127] FIG. 3 illustrates a sensing signal transmission procedure in a wireless charging system according to an embodiment of the present invention. This is a drawing for

[0128] As an example, the wireless power transmitter may be equipped with three transmitting coils 111, 112, and 113. Each transmitting coil may overlap with another transmitting coil in some areas, and wireless power The transmitters each have a predetermined sensing function for sensing the presence of a wireless power receiver through their respective transmitting coils. The signal 117, 127 - e.g., digital ping signals - are sent in a predefined order. Next send.

[0129] As shown in FIG. 3, the wireless power transmitter receives a first sensing signal shown by reference numeral 110. The signal strength is then calculated from the signal strength of the wireless power receiver 115. Signal Strength Indicator (116) was received The transmit coils 111, 112 can be identified.

[0130] Next, the wireless power transmitter goes through the secondary sensing signal transmission procedure shown in drawing number 120. The transmit coil 111 then transmits a sensed signal 127 in response to the received signal strength indicator 126. , 112, power transfer efficiency (or charging efficiency) - i.e., the efficiency of the transmitting coil and the receiving coil Identifies the best-aligned transmitter coil and transmits power through the identified transmitter coil. In other words, it is possible to control the charging of the battery so that the battery is charged wirelessly.

[0131] As shown in FIG. 3, why the wireless power transmitter performs the sensing signal transmission procedure twice This allows for more accurate identification of which transmit coil the receive coil of the wireless power receiver is well aligned with. This is to distinguish them.

[0132] If the first transmitting coil 11 is connected to the first transmitting coil 11 as shown in FIG. 1. When the signal strength indicator 116, 126 is received by the second transmitting coil 112, the wireless power The transmitter receives the signal strengths of the first and second transmitting coils 111 and 112. Select the best aligned transmit coil based on the indicator 126, and select the selected transmit coil. This is used to perform wireless charging.

[0133] FIG. 4 is a state transition diagram illustrating a wireless power transmission procedure according to an embodiment of the present invention. do.

[0134] Referring to FIG. 4, the power transfer from a transmitter to a receiver according to one embodiment of the present invention is large. Selection Phase (410), Ping Phase (410) hase, 420), Identification and Construction Phase Negotiation Phase, 430 Phase, 440), Calibration Phase, 450, Power Transfer Phase (460) and Renegotiation The process can be divided into two phases: Renegotiation Phase (470).

[0135] A selection step 410 selects a particular error while initiating the transfer of power or maintaining the transfer of power. or a transition step when a specific event is detected, e.g., S402, S404 , S408, S410 and S412.

[0136] Here, the specific errors and events will become clearer through the following description.

[0137] Also, in a selection step 410, the transmitter monitors whether an object is present on the surface of the interface. Can be ringed.

[0138] If the transmitter detects that an object has been placed on the surface of the interface, the ping stage It is possible to transition to floor 420 (S403).

[0139] As an example, in selection step 410, the transmitter may send a very short pulse of analog ping (Anal og Ping) signal and the transmitting coil (or primary coil Based on the current change in the active area (Active Aril) on the surface of the interface, ea) can sense the presence of an object. Here, the active area is the area where the receiver is located. It can refer to an area where wireless charging is possible.

[0140] As another example, in the selection step 410, the transmitter may select an interface using an installed sensor. The device may detect the presence of an object in the active area on the surface of the device. .

[0141] For example, sensors include Hall sensors, pressure sensors, capacitance sensors, current sensors, voltage The sensor may include a light sensor, and at least one of the sensors may be The sensor can sense an object placed on the active area in a controlled manner.

[0142] If an object is detected in the selection step 410, the wireless power transmitter selects the LC resonant circuit For example, an LC resonant circuit consists of a coil (inductor) and a resonant capacitor connected in series. It is possible to measure a quality factor corresponding to -.

[0143] When an object is detected in the selection step 410, the transmitter according to an embodiment of the present invention selects a different object in the charging area. A quality factor (QF) is used to determine whether a wireless power receiver is placed with an object. actor) values ​​can be measured.

[0144] Here, the quality factor value may be measured before entering the ping stage 420. can be measured with power transmission through the transmit coil temporarily interrupted.

[0145] As an example, the quality factor value may be measured for a predefined reference operating frequency. .

[0146] As another example, the quality factor value is set to a certain frequency within the operating frequency band used for wireless power transmission. Measurement may be performed by sampling in several units.

[0147] The transmitter according to an embodiment of the present invention has a maximum quality factor value measured within the operating frequency band. The frequency value corresponding to the quality factor value having a value can be determined and stored in memory. For the sake of convenience, the frequency at which the quality factor value is maximum within the operating frequency band is defined as the quality factor. Quality Factor Peak Frequency For convenience of explanation, this will be simply called the peak frequency.

[0148] The distribution of quality factor values ​​and quality factor peak frequencies measured corresponding to the operating frequency band are It may vary depending on the type of wireless power transmitter.

[0149] In particular, a transmitter used to authenticate a receiver to the same operating frequency - as described below For convenience, we will call it the "certification transmitter" - and the quality factor measured using an LCR meter. The product values ​​may differ from quality factor values ​​measured with commercial transmitters.

[0150] When the signal strength packet is received in the ping step 420, the wireless power transmitter performs identification and configuration. Then, the process proceeds to step 430 (S403).

[0151] Once the wireless power transmitter has successfully completed the identification and configuration procedures, it enters into the negotiation phase 440. This can be done (S405).

[0152] In addition, once the wireless power transmitter has successfully completed the identification and configuration procedure, it will automatically Then, the power transfer stage 460 may be entered (S406).

[0153] When the wireless power transmitter enters the negotiation stage 440, the wireless power receiver transmits a reference quality factor value. Included Foreign Object Detection Status Packet Status Packet).

[0154] The wireless power transmitter determines a quality factor critical value based on the received reference quality factor value. can be done.

[0155] Then, the wireless power transmitter compares the measured quality factor value with the quality factor critical value to determine the presence of a foreign object. It is possible to determine whether or not a person is present.

[0156] However, the critical value of a given quality factor determined based on the reference quality factor value and the measured quality factor A foreign object detection method that detects the presence or absence of a foreign object by simply comparing the values ​​of the foreign objects is applied to commercial transmitters. In such a case, the accuracy of foreign object detection may be low.

[0157] Here, the reference quality factor value is measured when no foreign object is placed in the charging area of ​​the authentication transmitter. This term refers to the quality factor value at a specified reference operating frequency.

[0158] The reference quality factor value received in the negotiation phase 440 and the reference movement measured before the ping phase 420 are Quality factor value corresponding to the operating frequency - hereinafter, for convenience of explanation, it is called the current quality factor value -The presence or absence of a foreign object can be determined by comparing the results.

[0159] However, the reference quality factor values ​​are different between the transmitter where the reference quality factor was measured - i.e. the authentic transmitter - and the current quality factor. The transmitters whose factor values ​​are measured may be different from each other. Therefore, it is difficult to determine whether a foreign object is present or not. The determined quality factor critical value for the measurement may not be accurate.

[0160] Therefore, the transmitter according to an embodiment of the present invention is a standard product corresponding to the type of the transmitter. receiving a quality factor value from the wireless power receiver; and determining a quality factor reference based on the received reference quality factor value. A threshold value may be determined.

[0161] The inductance and / or current in the transmitter coil may change due to changes in the surrounding environment. The series resistance component may be reduced, which may cause the resonant frequency of the corresponding transmission coil to change (shift) That is, the quality factor is the frequency at which the maximum quality factor value within the operating frequency band is measured. The factor peak frequency may be shifted.

[0162] For example, a wireless power receiver uses a magnetic shield with high magnetic permeability. Because of the high magnetic permeability, the inductance measured by the transmitting coil can be increased. On the other hand, metallic foreign objects can reduce the inductance value.

[0163] Generally, for an LC resonant circuit, the resonant frequency (f_resonant) is

number

[0164] When only the wireless power receiver is placed in the charging area of ​​the transmitter, the L value increases, so the resonant frequency In other words, the resonant frequency shifts to the left on the frequency axis. do.

[0165] On the other hand, if a foreign object is placed in the charging area of ​​the transmitter, the L value decreases, and the resonant frequency increases. In other words, the resonant frequency shifts to the right on the frequency axis.

[0166] In another embodiment of the present invention, the transmitter changes the charging region based on the change in the quality factor peak frequency. The presence or absence of a foreign object placed in the

[0167] The transmitter will respond to the preset quality factor peak frequency for that transmitter type. Hereinafter, for convenience of explanation, the "reference quality factor peak frequency (pf_reference)" or "reference peak frequency" - information obtained from the receiver or Therefore, the data can be maintained in a predetermined recording area.

[0168] When the transmitter detects that an object has been placed in the charging area, it The quality factor value within the operating frequency band is measured, and the quality factor peak frequency is calculated based on the measurement result. Here, the identified quality factor peak frequency can be used as a reference quality factor peak frequency. To distinguish it from the frequency, we use the "measured quality factor peak frequency (pf_measured)" This will be called the "measured peak frequency."

[0169] In a negotiation step 430, the transmitter negotiates a frequency based on the reference quality factor peak frequency and the measured quality factor peak frequency. The presence or absence of a foreign object may be determined based on this.

[0170] If information about the reference quality factor peak frequency is received from the receiver, identification and The information may be received in a predetermined packet during the configuration step 430 or the negotiation step 440 .

[0171] In one example, the transmitter may identify and configure 430 by receiving information about its type of transmitter. The receiver can then transmit the type information of the transmitter to the receiver. The previously stored reference quality factor peak frequency is read from the corresponding memory. Information regarding the reference quality factor peak frequency may be transmitted to the transmitter.

[0172] According to yet another embodiment of the present invention, a transmitter is provided for detecting a foreign object based on a quality factor peak frequency. All foreign object detection methods based on the detection method and quality factor value are used to determine whether or not foreign objects are present. As an example, a reference quality factor value corresponding to a type of transmitter and a measured quality factor If the comparison of the values ​​shows that there is no significant difference - for example, the difference between the two values ​​is less than 10% - the transmitter Compare the measured quality factor peak frequency with the reference quality factor peak frequency corresponding to the type of On the other hand, if the difference between the two quality factor values ​​exceeds 10%, In this case, the transmitter can immediately determine that a foreign object is present.

[0173] In another embodiment, the quality factor determined based on a reference quality factor value corresponding to the type of transmitter. If the comparison of the critical value with the measured quality factor value indicates that there is no foreign object, the transmitter Reference quality factor peak frequency and measured quality factor peak frequency for the transmitter type The presence or absence of a foreign object may be determined by comparing the two.

[0174] If the transmitter is not able to detect the foreign object based on the quality factor value, the receiver If you request information about the reference quality factor peak frequency for the applicable transmitter type from the After this, the transmitter receives information about the reference quality factor peak frequency from the receiver. The presence or absence of a foreign object is determined by using the reference quality factor peak frequency and the measured quality factor peak frequency. Through this, the transmitter can more accurately detect foreign objects placed in the charging area. can be detected.

[0175] When the transmitter detects an object, it goes to a ping step 420 to wake up the receiver. up) and digital pinging to identify whether the detected object is a wireless power receiver. (Digital Ping) can be transmitted.

[0176] In a ping step 420, the transmitter receives a response signal to the digital ping, e.g., a signal strength If no packet is received from the receiver, then a transition can be made to selection step 410 again.

[0177] Also, in a ping step 420, the transmitter indicates to the receiver that the transmission of power is complete. Upon receiving a signal, ie, a charging complete packet, a transition may be made to a selection step 410 .

[0178] Once the ping step 420 is complete, the transmitter identifies the receiver and returns the receiver configuration and status information. The process may proceed to an identification and configuration stage 430 for collecting the

[0179] The transmitter transmits information regarding the type of the transmitter to the receiver in an identification and configuration step 430. Good too.

[0180] The receiver requests information about the type of transmitter from the transmitter in an identification and configuration step 430. The transmitter may also transmit information about the type of the transmitter to the receiver upon request of the receiver. good.

[0181] Also, in the identification and configuration step 430, the transmitter may detect whether an unwanted packet is received (un expected packet), the desired packet is not received for a predefined period of time. The packet was not received (time out), or there was a packet transmission error (transmission ission error), if the power transfer contract is not set (no power transfer The process may proceed to a transfer contract selection step 410.

[0182] The transmitter identifies the configuration packet received in the identification and configuration step 430. ion packet) Negotiation Field value Based on this, it can be ascertained whether entry into the negotiation phase 440 is necessary.

[0183] If negotiation is necessary, the transmitter proceeds to a negotiation step 440 to determine the FOD detection method. You can continue.

[0184] On the other hand, if the confirmation result indicates that negotiation is not necessary, the transmitter immediately proceeds to the power transmission step 460. This is also fine.

[0185] In one embodiment, the wireless power transmitter identifies the corresponding wireless power receiver in the identification and configuration step 430. If it is determined that the receiver supports only one power transmission mode, the negotiation step 440 is performed. 4. Instead, the power transfer step 460 may be immediately performed.

[0186] After entering the power transmission step 460, the wireless power transmitter periodically performs a predetermined foreign object detection procedure. It is possible.

[0187] Here, the foreign object detection procedure may be a foreign object detection procedure based on the quality factor value. Foreign object detection procedures based on, but not limited to, power loss are applied. It is possible.

[0188] The power loss-based foreign object detection procedure is based on the transmission power of the wireless power transmitter and the received power of the wireless power receiver. A method for determining whether or not a foreign object is present by comparing the difference in transmission power with a predetermined reference value, The rest will become clearer through the description of the drawings below.

[0189] As an example, in the negotiation step 440, the transmitter may send a foreign object detection status packet including a reference quality factor value. FOD (Foreign Object Detection) Status P acket) or the reference peak frequency corresponding to the transmitter type. You can receive an FOD Status Packet that contains a numerical value.

[0190] As another example, during negotiation step 440, the transmitter may select a reference quality factor value corresponding to the type of transmitter. and a reference peak frequency value. A quality factor threshold value for detecting a foreign object is calculated based on a reference quality factor value corresponding to the type of transmitter. It can be determined.

[0191] The transmitter determines the likelihood of foreign object detection based on the reference quality factor peak frequency value corresponding to the transmitter type. A quality factor peak frequency threshold for the

[0192] The transmitter is configured to determine the quality factor critical value and / or the quality factor peak frequency. The quality factor value measured as the critical value-means the quality factor value measured before the ping step 420. - and / or - measuring the quality factor peak frequency value and comparing it with the foreign object placed in the charging area It may be detected.

[0193] The transmitter can control the power transmission depending on the result of the foreign object detection. If issued, the transmitter shall send a Negative Response packet in response to the Foreign Object Detection Status packet. A negative acknowledge packet is sent to the receiver. Accordingly, the power transmission may be interrupted, but this is not limited to this.

[0194] The transmitter determines the determined quality factor peak frequency critical value and the measured quality factor peak frequency value. By comparing the results, it is possible to detect foreign objects placed in the charging area. As an example, if a foreign object is detected, the transmitter can NACK in response to FOD Status Packet Send a packet (Negative acknowledge packet) to the receiver Accordingly, power transmission may be interrupted, but is not limited to this.

[0195] If a foreign object is detected, the transmitter sends an End of Charge message (ECM) to the receiver. A message (Message) may be received, which allows the selection step 410 to proceed. It is possible.

[0196] According to another embodiment of the present invention, when a foreign object is detected in the negotiation step 440, the transmitter Step 460 may be entered (S415).

[0197] On the other hand, if no foreign object is detected, the transmitter completes the negotiation step 440 for the transmission power. After the correction stage 450, the power transfer stage 460 may be entered (S407 and S409). .

[0198] In detail, if no foreign object is detected, the transmitter enters the correction stage 450 and the receiving stage The strength of the power received is determined, and the strength of the power to be transmitted at the transmitting stage is determined. The power loss between the signal stages can be measured.

[0199] As an example, the transmitter uses the strength information of the received power fed back from the receiving stage during power transmission. Based on the information, the transmitter can determine the strength of the received power to the receiver. In step 450, a power loss is calculated based on the difference in intensity between the transmitted power at the transmitting stage and the received power at the receiving stage. The loss can be predicted (or calculated).

[0200] In the power transmission step 460, the transmitter detects whether an unwanted packet is received or not. ted packet), which occurs when a desired packet has not been received for a predefined period of time. (time out), or a violation of the established power transfer agreement ( power transfer contract violation), charging is complete If so, the process may proceed to selection step 410 (S410).

[0201] In addition, in the power transmission step 460, the transmitter may transmit a power transmission contract due to a change in the state of the transmitter. If reconfiguration is necessary, a transition to a renegotiation stage 470 can be made (S411). If the renegotiation is successfully completed, the transmitter may transition back to the power transfer stage 460. (S413).

[0202] The power transfer agreement can be set based on the status and characteristic information of the transmitter and receiver. For example, the transmitter status information may include information on the maximum transmittable power, the maximum accommodable receive power, and the like. The receiver status information may include information on the number of receivers, etc., and the receiver status information may include information on the required power, etc. etc.

[0203] The wireless power transmitter according to the embodiment of the present invention is configured to receive the guaranteed power required by the wireless power receiver. Based on the above, one of the first power transmission mode and the second power transmission mode is selected. It can operate in the mode.

[0204] A wireless power transmitter according to another embodiment of the present invention performs a power supply control based on a result of determining whether or not a foreign object is present. Based on this, in either the first power transmission mode or the second power transmission mode, It can work.

[0205] The wireless power receiver connected to the wireless power transmitter is a receiver that supports only the first power transmission mode. The present invention may be a receiver that supports both the first power transmission mode and the second power transmission mode. .

[0206] Here, the guaranteed power that can be set in accordance with the second power transmission mode is set in the first power transmission mode. The power may be greater than the guaranteed power that can be determined.

[0207] As an example, the guaranteed power that can be set in the first power transmission mode is the first power - for example, 5W or is 5W or less, and the guaranteed power that can be set in the second power transmission mode is greater than the first power, The second power may be less than, for example, 15W.

[0208] FIG. 5 illustrates a foreign object detection procedure in a wireless power transmission system according to an embodiment of the present invention. 1 is a flowchart for

[0209] In detail, FIG. 5 is a diagram for explaining a foreign object detection procedure in the second power transmission mode. .

[0210] Referring to FIG. 5, when an object is detected in the selection stage, the wireless power transmitter 510 starts the ping stage. Before entering a floor, a quality factor value at a predetermined reference operating frequency can be measured (S501). Here, the reference operating frequency is the resonance frequency. The wireless power transmitter 510 may, but is not limited to, transmit the measured quality factor value. It can be stored in the internal memory (S502).

[0211] The wireless power transmitter 510 enters the ping stage and transmits the sensing signal as described in FIG. The task can be accomplished (S503).

[0212] When the wireless power transmitter 510 detects the wireless power receiver 520, it begins the identification and configuration phase. It can enter and receive identification and configuration packets (S504 and S5 05).

[0213] The wireless power transmitter 510 enters into a negotiation phase and transmits a foreign object detection status packet to the wireless power receiver 5 20 (S506). Here, the foreign object detection status packet can be received from the reference quality It may include factor values.

[0214] The wireless power receiver 510 detects the foreign object based on the reference quality factor value included in the foreign object detection status packet. A threshold value for determining whether an object is present or not can be determined (S507).

[0215] For example, the critical value may be determined to be a value smaller than the reference quality factor value by a predetermined ratio.

[0216] The wireless power transmitter 510 detects foreign objects by comparing the measured quality factor value with the determined critical value. If the measured quality factor value is smaller than the critical value, the quality factor is output (S508). For example, the wireless power transmitter 510 can determine that a foreign object is present in the charging area.

[0217] The wireless power transmitter 510 sends an ACK response, a NACK response, or an ND response according to the result of the foreign object detection. (No Decision) response can be transmitted to the wireless power receiver 520 (S5 09).

[0218] The wireless power receiver 520 receives a NACK response or an ND response from the wireless power transmitter 510. Then, the wireless power transmitter 510 will continue to transmit power to its output terminal until it completely stops transmitting power. To prevent the power supplied to the electronic device (or battery / load) from exceeding a certain level, It can be controlled as follows.

[0219] Here, the power of a certain intensity or more may be 5W as a standard, but is not limited thereto. The manufacturer's design and the electronic device and (or wireless power receiver) equipped with the wireless power receiver 510 The load may be defined differently depending on the load (battery / load coupled to the receiver 510).

[0220] FIG. 6 is a block diagram illustrating a structure of a wireless power transmission device according to an embodiment of the present invention. It is.

[0221] Referring to FIG. 6, a wireless power transmission device 600 includes a controller 610, a gate driver (Gat e Driver, 620), inverter (Invertor, 630), transmission antenna 640, power supply 650, power supply (Power Supply, 660), sensor 670 and a demodulator 680.

[0222] The power supply 660 converts the DC or AC power applied from the power source 650 into an input For the sake of convenience, the following description will be given with reference to the power supply 660. The voltage supplied to the inverter 630 from the inverter input voltage or the vehicle rail (V_r We decided to name it "ail".

[0223] The power supply 660 is configured to convert the AC / DC power into a DC voltage depending on the type of power applied from the power supply 650. (AC / DC Converter) and DC / DC Converter rter).

[0224] As an example, the power supply 660 may be a switching mode power supply. Mode Power Supply (SMPS), and switching transistor A switch control method for converting AC power into DC power using a converter, filter, rectifier, etc. Here, the rectifier and filter are configured independently to provide the AC power source. It may be disposed between the SMPS.

[0225] SMPS controls the on / off time ratio of semiconductor switching elements to output A power supply device that supplies a stabilized DC power supply to a corresponding device or circuit element, It is widely used in many electronic devices and equipment because it is highly efficient, compact and lightweight. is.

[0226] The quality of the power supply often determines the stability and precision of electronic circuit operation. There are many different methods for converting and supplying stable power from batteries and commercial AC power sources. Series regulator type and switch mode There is a (mode) method.

[0227] The linear control method used in TV receivers and CRT monitors has simple peripheral circuits and is inexpensive. Although they are cheap, they have the disadvantages of generating a lot of heat, having low power efficiency, and being large in volume.

[0228] On the other hand, switching mode technology generates almost no heat, is power efficient, and has a small volume. Although it has the advantage of being small, it is expensive, has a complex circuit, and requires high-frequency switching output. The drawback is that noise and electromagnetic interference may occur.

[0229] As another example, the power supply 660 may be a variable SMPS (variable switch A variable SMPS is an AC power supply. Switches the AC voltage in the tens of Hz range output from the AC Power Supply. The converter converts and rectifies the input voltage to produce a DC voltage.

[0230] Variable SMPS can output a constant level DC voltage or The DC voltage output level is controlled by the Tx Controller. The variable SMPS is designed to ensure that the power amplifier of the wireless power transmitter is always in the saturation region where it is highly efficient. Depending on the output power level of the power amplifier, i.e., the inverter 530, the The supply voltage can be adjusted as needed to maintain maximum efficiency at all output levels. do.

[0231] If a commonly used commercial SMPS is used instead of a variable SMPS, an additional variable A DC / DC converter (Variable DC / DC) can be used. Commercial SMPS The variable DC / DC converter and the power amplifier are designed to operate in the saturation region where they are highly efficient. Supply voltage is controlled according to amplifier output power level to maintain maximum efficiency at all output levels In one embodiment, the power amplifier is of Class E type. It can be used, but is not limited to this.

[0232] The inverter 630 receives the signal from the gate driver 620 at a frequency of several MHz to several tens of MHz. Bandwidth switching pulse signal - i.e. Pulse Width Modulation (PWM) odulated) signal - converts a constant level DC voltage (V_rail) into an AC voltage By converting it, it is possible to generate AC power that can be transmitted wirelessly.

[0233] At this time, the gate driver 620 receives the reference clock R To control a plurality of switches included in the inverter 630 using the ef_CLK signal A plurality of PWM signals SC_0 to SC_N can be generated.

[0234] Here, if the inverter 630 includes a half-bridge circuit, N is 1; If the converter 630 includes a full bridge circuit, N may be, but is not limited to, 3. Depending on the design of the inverter 630, different numbers of PWM signals are provided for different inverter types. may be provided.

[0235] For example, in the embodiment of FIG. 6, the inverter 630 is a full bridge circuit including four switches. If included, inverter 630 generates four PWM signals S for controlling the respective switches. C_0, SC_1, SC_2, and SC_3 can be received from the gate driver 620. do.

[0236] On the other hand, in the embodiment of FIG. 6, the inverter 630 is a half-bridge circuit including two switches. If included, inverter 630 generates two PWM signals S for controlling the respective switches. C_0, SC_1 can be received from the gate driver 620.

[0237] The transmission antenna 640 wirelessly transmits the AC power signal received from the inverter 630. At least one power transmission antenna (not shown) for transmitting power to the and a matching circuit (not shown) for impedance matching. do.

[0238] In addition, when the transmission antenna 640 is provided with a plurality of transmission coils, the transmission antenna 640 The coil selection circuit selects a transmitting coil to be used for wireless power transmission from among a plurality of transmitting coils. A selection circuit (not shown) may also be included.

[0239] The sensor 670 detects the strength of the power / voltage / current input from the inverter 630 or b) The strength of the power / voltage / current flowing through the transmission coil provided in the transmission antenna 640, Specific locations inside the power transmitter - including, for example, the transmitting coil, charging bed, control circuit board, etc. - Various sensors for measuring temperature and / or temperature changes in The information sensed by the sensor 670 may be used as a control circuit. The signal may be transmitted to the device 610.

[0240] Also, the sensor 670 is connected to the transmitting controller during the analog ping transmission in the selection steps 410 and 510. The intensity of the current flowing through the coil can be measured and communicated to the controller 610. In the selection stage, the strength information of the power flowing through the transmitting coil is compared with a predetermined reference value and the device is placed in the charging area. The presence or absence of a detected object can be sensed.

[0241] When the wireless power transmitter 600 performs in-band communication with the wireless power receiver, the wireless power transmission The receiver 600 may include a demodulator 680 coupled to a transmit antenna 640 .

[0242] The demodulator 680 can demodulate the amplitude modulated in-band signal and transmit it to the controller 610. can.

[0243] In one example, the controller 610 may transmit a demodulated signal based on the demodulated signal received from the demodulator 680. Signal Strength Indicator for Digital Ping You can check whether the mail cator has been received or not.

[0244] When the controller 610 detects an object placed in the charging area in the selection step 410, the controller 610 performs a ping step 420 to control the digital ping to be transmitted through the transmission antenna 640. It is possible.

[0245] When the controller 610 detects an object placed in the charging area in the selection step 410, the controller 610 performs a ping step Before entering the power supply, the power transmission can be temporarily interrupted and the quality factor value measured. The determined quality factor value is maintained in a predetermined memory (not shown) provided in the wireless power transmitter 600. It can be held.

[0246] The controller 610 transmits a digital ping signal upon receipt of a signal strength indicator during the ping phase. The transmission is interrupted and the identification and configuration step 430 is entered to receive the identification packet and the configuration packet. It can be trusted.

[0247] When the controller 610 receives a power transmission end packet after entering the power transmission step 460, Power transfer may be interrupted and selection step 410 may be entered.

[0248] In addition, the controller 610 stops the power transmission and performs the selection step 4 when a foreign object is present in the charging area. You may enter 10.

[0249] According to one embodiment, the controller 610 may be configured to receive a received signal strength packet (RSP) from a wireless power receiver. The power loss on the wireless power transmission path can be calculated (or estimated) based on the control The device 610 may determine the presence or absence of a foreign object based on the calculated (or estimated) power loss. good.

[0250] In another embodiment, the controller 610 may be configured to receive temperature sensing information from the sensor 670. or a temperature change can be measured based on temperature measurement information received from a wireless power receiver. The controller 610 may determine whether or not a foreign object is present based on the measured temperature change. .

[0251] In yet another embodiment, the controller 610 estimates the power loss and determines the power loss based on the estimated power loss. A method for determining the presence or absence of a foreign object based on temperature change is provided based on the result of the determination of the presence or absence of a foreign object based on temperature change. You may continue.

[0252] In yet another embodiment, the controller 610 determines whether a foreign object is present based on a change in temperature. Depending on the results, a procedure for determining whether or not a foreign object is present based on the power loss may be performed.

[0253] In addition, when the controller 610 according to the present invention receives an FOD status packet in the negotiation step 440, , determining a threshold value for detecting a foreign object based on the received FOD status packet, The presence or absence of a foreign object may be determined based on the determined critical value.

[0254] Here, the FOD state packet is a reference quality factor value, a resonant frequency, and a quality factor at the resonant frequency. It may contain at least one of the values.

[0255] The controller 610 receives the ripping code or the overload code through the demodulator 680 in the power transmission stage 460. If a power transmission end packet containing a thermal code is received, the power transmission is stopped and the selection stage is started. Floor 410 may be entered to activate the rip timer.

[0256] The controller 610 transmits and receives analog pings until the activated ripping timer expires. The output of the ripping and beep signals can be suppressed. Then, when the ripping timer expires, Then, the controller 610 goes to a ping step 420 and transmits the digital signal via the transmission antenna 640. The pings can be controlled to be transmitted.

[0257] After the controller 610 has completed identification and configuration of the detected receiver, it starts the ripping controller. When a power transfer termination packet containing a rip code or overheat code is received, the rip time After resetting, the process can return to selection step 410.

[0258] The operation modes of the wireless power transmitter 600 according to the embodiment of the present invention are a first power transmission mode and A second power transfer mode may be included.

[0259] The controller 610 determines whether or not a foreign object is present in the negotiation step 440. The power transmission mode is operated in either one of the first power transmission mode and the second power transmission mode. This can be done.

[0260] Here, the guaranteed power in the second power transmission mode is the guaranteed power (or the maximum Large transmission power) may be larger.

[0261] For example, the guaranteed power in the first power transmission mode is 5W or less, which is called the first power. and the guaranteed power in the second power transmission mode may be 15W or less, which is named the second power. do.

[0262] As another example, the guaranteed power in the first power transmission mode is 5 W, and the guaranteed power in the second power transmission mode is 5 W. The guaranteed power in the power supply may be a value between the first power and the second power, but is not limited thereto, and may be any value within the range known to those skilled in the art. The guaranteed power corresponding to each operation mode may be set differently depending on the design of the user. It is important to be careful.

[0263] If a foreign object is present as a result of the determination in the negotiation step 440, the controller 61 0 is the level of the guaranteed power from the second level corresponding to the second power transmission mode to the first power transmission mode. The level can be changed to the first level corresponding to the code.

[0264] That is, if the controller 610 determines in the negotiation step 440 that a foreign object is present, the controller It is possible to adjust the power downward. This prevents overheating caused by foreign objects during high power transmission. This can prevent the device from being damaged.

[0265] When the controller 610 enters the first power transfer mode, the compensation step 450 of FIG. 4 is performed. It is possible to control the amount of

[0266] If the correction step 450 is performed in the first power transmission mode despite the presence of a foreign object in the charging area, When implemented, the power loss-based foreign object detection method has a problem of low accuracy.

[0267] Generally, the correction step 450 is a procedure that is performed under the assumption that no foreign objects are present. Therefore, if the correction step 450 is performed despite the presence of a foreign object in the charging area, The problem with foreign object detection methods based on force loss is that they are less accurate and less reliable.

[0268] If, after entering the first power transmission mode, the power loss-based foreign object detection method and ( Or) if no foreign object is detected through the foreign object detection method based on the temperature change, the controller 610 can enter into the renegotiation step 470 of FIG.

[0269] When the power transmission contract is confirmed as a result of renegotiation with the wireless power receiver, the controller 610 The operating mode may be changed according to the power transmission contract.

[0270] As an example, the power transmission contract may include a guaranteed power, and the controller 610 may The guaranteed power can be changed through renegotiation procedures with the equipment.

[0271] If the renegotiation result indicates that the guaranteed power required by the wireless power receiver is in the first power transmission mode, When the corresponding first guaranteed power is changed to the second guaranteed power corresponding to the second power transmission mode The controller 610 may switch the operation mode from the first power transmission mode to the second power transmission mode. good.

[0272] As described in the above embodiment, the wireless power transmitter 600 according to the present invention can be used in the absence of a foreign object. Even if a foreign object is detected, charging will not continue. This has the advantage of being

[0273] In particular, the wireless power transmitter 600 actually operates in a different power transmission mode during the initial second power transmission mode. If the device detects the presence of a foreign object even though no object is present, it will immediately stop charging. Charging is performed by switching the power transmission mode from the second power transmission mode to the first power transmission mode without interrupting the power supply. can be maintained.

[0274] As an example, the wireless power transmitter 600 is configured such that the wireless power receiver is placed in the charging area without any foreign objects. Even if the transmitter coil and receiver coil are in a charged state, there may be foreign objects in the charging area due to the alignment between the transmitter coil and receiver coil. It may be assumed that it exists.

[0275] The wireless power transmitter 600 according to the present invention is also able to detect additional foreign objects even after switching to the first power transmission mode. By carrying out the detection procedure, it is possible to detect foreign objects more accurately. Additional foreign object detection procedures include a power loss based foreign object detection procedure and a temperature change based foreign object detection procedure. The method may include at least one of the following foreign object detection procedures:

[0276] FIG. 7 is a diagram illustrating a configuration of the transmission antenna of FIG. 6 according to an embodiment of the present invention. It is.

[0277] Referring to FIG. 7, the transmission antenna 640 includes a coil selection circuit 710, a coil assembly 7 20 and a resonant capacitor 730.

[0278] The coil assembly 720 includes at least one transmitting coil, i.e., coils 1 to N. - may be configured to include.

[0279] The coil selection circuit 710 selects one of the transmission coils included in the coil assembly 720. The inverter 630 output current I_coil is transmitted to one or at least one of the The switching circuit may include a switching circuit configured to:

[0280] As an example, the coil selection circuit 710 has one end connected to the inverter output stage and the other end The first to Nth switches may be connected to the corresponding coils.

[0281] The first to Nth coils included in the coil assembly 720 are connected at one end to a coil selection circuit 71. 0, and the other end may be coupled to the resonant capacitor 730.

[0282] The demodulator 680 demodulates the signal between the coil assembly 720 and the resonant capacitor 730, where The signal is an amplitude modulated signal and can be demodulated and transmitted to the controller 610 .

[0283] FIG. 8 is a block diagram showing a wireless power supply in cooperation with the wireless power transmitting apparatus according to the embodiment of the present invention shown in FIG. FIG. 2 is a block diagram for explaining the structure of a receiving device.

[0284] Referring to FIG. 8, a wireless power receiver 800 includes a receiving antenna 810, a rectifier 820, a DC / DC / DC Converter (830), Switch 840, Load 85 0, a sensing unit 860, a modulation unit 870, and a main control unit 870.

[0285] The wireless power receiver 800 shown in the example of FIG. 8 transmits wireless power through in-band communication. It can exchange information with the transmitter.

[0286] The receiving antenna 810 may include an inductor and at least one capacitor. do.

[0287] The AC power transmitted by the wireless power transmitter 600 is rectified through the receiving antenna 810. The rectifier 820 can transmit the received signal through the receiving antenna 810 to the receiving antenna 820. The AC power may be converted to DC power and transmitted to a DC / DC converter 830 .

[0288] The DC / DC converter 830 adjusts the strength of the output DC power of the rectifier 820 according to the demands of the load 850. The DC power can be converted to a specific intensity to be used.

[0289] The sensing unit 840 measures the intensity of the output DC power of the rectifier 820 and controls the main controller based on the measurement result. The information can be provided to unit 880.

[0290] The main controller 880 can perform power control based on the output DC power of the rectifier 820. Cut.

[0291] The sensing unit 840 detects the current applied to the receiving antenna 810 by wireless power reception. The intensity of the light may be measured and the measurement result may be transmitted to the main controller 880.

[0292] The sensing unit 840 may be a device that is connected to the wireless power receiver 800 or a device that is connected to the wireless power receiver 800. The internal temperature of the electronic device may be measured and the measured temperature value may be provided to the main controller 880. stomach.

[0293] As an example, the main controller 880 may set the intensity of the measured output DC power of the rectifier as a predetermined reference value. By comparing the voltages, it is possible to determine whether an overvoltage has occurred. The control unit 880 transmits a predetermined packet notifying the occurrence of an overvoltage through the modulation unit 870. The signal can be transmitted to a line power transmitter 600 .

[0294] When the modulation unit 870 receives a packet from the main control unit 880, the modulation unit 870 transmits the packet through the receiving antenna 810. The received AC power and the associated switch are used to In this case, the wireless power transmitter 600 can generate an amplitude modulated signal. The signal amplitude modulated by the receiver 800 can be demodulated by the demodulator 680. Cut.

[0295] As an example, the modulator 870 receives a signal strength packet from the main controller 880 during the ping phase. Then, the digital ping received through the receiving antenna 1010 is The signal can be amplitude modulated to correspond to a packet of pulses.

[0296] According to an embodiment, the modulator 870 modulates the AC power signal received through the receiving antenna 810. In this case, the main control unit 880 may be provided with a modulation switch for amplitude modulating the transmission pair. A pulse width modulation signal corresponding to the image packet is transmitted to the modulation unit 870 to directly control the modulation switch. You may control it.

[0297] In addition, the main control unit 880 outputs a detection signal when the intensity of the output DC power of the rectifier is equal to or greater than a predetermined reference value. When a signal - for example, a digital ping - is received, it can be determined that the signal is received. The signal strength packet corresponding to the corresponding sensing signal is wirelessly transmitted through the modulation unit 870. The signal can be transmitted to the machine.

[0298] For example, the main controller 880 may turn on the switch 840 when the internal temperature exceeds a predetermined reference value. By controlling, for example, by switching OFF the DC power output from the DC / DC converter 830, the load 85 In this case, the main controller 880 may control the overheat code so that the overheat code is not transmitted to 0. The power transmission interruption packet is transmitted to the wireless power transmitter 600 through the modulation unit 1070. can be done.

[0299] As another example, the main control unit 880 may be implemented as a controller in an electronic device in which the wireless power receiver 800 is installed. Power management element that controls power - for example, PMIC (Power Management It can be linked to IC.

[0300] In this case, the output DC power of the DC / DC converter 1030 is fed to the power supply 820 through the switch 840. The power management element can then charge the battery and provide power to the internal components of the electronic device. The power supply can be controlled.

[0301] The power management components can provide battery charge status information to the main controller 880. The main control unit 880 controls the progress of charging based on the battery charge state information and internal temperature information. You can decide whether it is possible or not.

[0302] When the wireless power receiver 800 according to an embodiment of the present invention enters the negotiation stage 440, the wireless power receiver 800 performs a foreign object detection. An outgoing status packet may be generated and transmitted to the wireless power transmitter 600 .

[0303] As an example, the Foreign Object Detection Status Packet may include a reference quality factor value.

[0304] As another example, the foreign object detection packet may correspond to a reference quality factor value and a corresponding wireless power receiver. The resonant frequencies may include

[0305] As yet another example, the foreign object detection packet includes a resonant frequency and a product corresponding to the resonant frequency. It may also include a quality factor value.

[0306] The wireless power transmitter 600 detects the foreign object based on the reference quality factor value included in the foreign object detection status packet. A predetermined threshold value for determining whether an object is present or not can be determined.

[0307] The wireless power receiver 800 according to the embodiment of FIG. 8 transmits the power transmitted by the wireless power transmitter 600. The packet may further include a demodulation unit (not shown) for demodulating the packets.

[0308] Through this, the wireless power transmitter 600 and the wireless power receiver 800 perform bidirectional communication. In one embodiment, the two-way communication is based on the packet transmission time and the wireless power transmission time of the wireless power transmitter. This may be time division communication in which the packet transmission time at the receiver is divided, but is not limited to this. I don't.

[0309] FIG. 9 shows a conventional power transmission control method according to the presence or absence of foreign object detection in a wireless power transmitter. 1 is a drawing for explanation.

[0310] When the wireless power transmitter receives a negotiation request packet from the wireless power receiver, it sends an acknowledgement packet ( Grant Packet) and proceed to negotiation step 440.

[0311] Referring to FIG. 9, in a negotiation step 440, the wireless power transmitter receives a foreign object detection state from the wireless power receiver. FOD (Foreign Object Detection) Status Packet s Packet) can be received (S901).

[0312] As an example, the wireless power transmitter may include a message field as shown in FIG. Reference Quality Factor Va 1031).

[0313] The wireless power transmitter can determine whether or not a foreign object is present (S902). The line power transmitter is measured after object detection in the selection step 410 and before proceeding to the ping step 420. quality factor values ​​determined based on the quality factor values ​​received in the negotiation phase 440 and the reference quality factor values ​​received in the negotiation phase 440 The critical values ​​can be compared to determine whether or not a foreign object is present.

[0314] In the following embodiment, the quality factor value is used as a method for detecting foreign objects after entering the negotiation stage 44. However, this is only one embodiment and may be subject to change without notice. The method for detecting foreign objects may be different depending on the design or the definition of the standard. It is important to be careful.

[0315] If the result of the judgment shows that no foreign object exists, the wireless power transmitter transmits an ACK signal to the corresponding wireless power receiver. The information can be sent (S903).

[0316] After this, the wireless power transmitter receives information about the guaranteed power required by the wireless power receiver. The included guaranteed power packet can be received (S904).

[0317] The wireless power transmitter can receive a negotiation completion packet from the wireless power receiver (S9 05).

[0318] When the wireless power transmitter receives the negotiation end packet, the wireless power transmitter performs the correction step 450 in the negotiation step 440. can enter.

[0319] The wireless power transmitter may enter a correction step 450 to perform a predetermined correction procedure (S906 ).

[0320] When the power transmission contract is completed through the correction procedure, the wireless power transmitter Then, the charging can be started (S907).

[0321] If it is determined in step 902 that a foreign object is present, the wireless power transmitter enters a foreign object detection state. In response to the state packet, a NACK signal can be transmitted (S908).

[0322] The wireless power receiver receives a NACK signal as a response to the foreign object detection status packet. and at its own output stage until the power signal received from the wireless power transmitter is completely removed. The power does not exceed a predetermined threshold, which may be, but is not limited to, 5W. It is possible to control it so that

[0323] The wireless power transmitter transmits a NACK signal within a predefined time period, e.g., 5 seconds. If necessary, the power transmission can be interrupted (S909).

[0324] When power transmission is interrupted, the wireless power transmitter may enter a selection stage 410 ( S910).

[0325] Transmitting power corresponding to a second power transmission mode when a foreign object is placed in the charging area. may increase the risk of equipment overheating.

[0326] Therefore, when a foreign object is detected in a conventional wireless power transmitter, the power transmission stage Blocking access to floor 460 and interrupting power transmission within a predefined time period before selecting Selection step 410 has been entered.

[0327] However, the wireless power transmitter is subject to the measurement error of the LCR meter installed, The difference in the mechanical design of the power supply and the wireless power receiver and the design of the coils attached to each Quality Factor Cross Calibration Error ration Error), the separation between the transmitting coil and the receiving coil - i.e., Z d istance- and the position of the wireless power receiver placed in the charging area- i.e., XY Displacement--etc., which detects the presence of foreign matter even though it is not actually present There is a possibility that it may be misjudged as something.

[0328] If there is no foreign object, the power transmission is interrupted and the selection stage is resumed. Returning such information could result in serious user inconvenience.

[0329] In particular, wireless power receivers used in smartphones, etc., are To achieve this, a shielding material with high magnetic permeability is used, and the thickness of the receiving coil is designed to be as small as possible. It can be done.

[0330] In this case, the resistance R can become very large and the quality factor Q can become very small. If the product is fitted with a metal housing, the quality factor Q may be lower.

[0331] This may increase the probability of error in determining whether or not a foreign object is present in the wireless power transmitter. do.

[0332] For example, if an error occurs in determining the presence of a foreign object, the smartphone may not be able to charge. A situation where a foreign object is judged to be a foreign object because the quality factor Q is measured low even though the object is placed in the area. It can also include situations where the smartphone is placed in the charging area.

[0333] Therefore, in order to solve the above-mentioned problems of the prior art, a device that prevents damage to the device due to overheating is required. There is a demand for a method for controlling power transmission in a wireless power transmitter that can prevent power transmission failures while minimizing user inconvenience. is.

[0334] FIG. 10 is a diagram illustrating a packet format according to an embodiment of the present invention. do.

[0335] The wireless power transmitting stage 10 and the wireless power receiving stage 20 according to the embodiment of the present invention communicate with each other through in-band communication. Although packets can be exchanged via out-of-band communication, this is only one embodiment. The corresponding packets may be exchanged accordingly.

[0336] Referring to FIG. 10, a wireless power transmitter stage 10 and a wireless power receiver stage 20 are used for information exchange. The packet format 1000 is used for obtaining synchronization for demodulating the corresponding packet and Preamble (101) to identify the exact start bit of the packet 0) field, a header to identify the type of message contained in the packet ( Header, 1020) field, the contents of the corresponding packet (or payload Message (1030) field for transmitting the and a checksum to check whether an error occurred in the corresponding packet. sum, 1040) fields.

[0337] The packet receiving stage detects the message 1 contained in the corresponding packet based on the header 1020 value. The size of 030 may be identified.

[0338] In addition, the types of packets that can be transmitted in stages in FIG. 4 are defined by the header 1020 value. In some cases, the value of the header 1020 may be shared between different stages of the wireless power transmission procedure. As an example, the ping stage 420 and the power transfer stage 460 may be defined so that End Power Tr to stop the power transmission of the wireless power transmitter An answer packet may be defined with the same header 1020.

[0339] The message 1030 includes data to be transmitted at the transmission stage of the corresponding packet. The data contained in the message 1030 field is the report to the other party. It can be a port, a request or a response. However, this is not limited to this.

[0340] The packet format 1000 according to another embodiment of the present invention transmits a corresponding packet. A transmitter identification information for identifying a transmitter, and a receiver identification information for identifying a receiver that receives the corresponding packet. The receiving stage identification information may further include at least one of the receiving stage identification information.

[0341] Here, the sender identification information and the receiver identification information are IP address information, MAC (Medi um Access Control) address information, product identification information, etc. However, this is not limited to the above, and information that can distinguish the receiving stage and the transmitting stage in the wireless charging system That's fine.

[0342] A packet format 1000 according to another embodiment of the present invention is a packet format 1000 in which the corresponding packet is multiplexed. If the signal must be received by multiple devices, a designated The group may further include a fixed group identification.

[0343] FIG. 11 is a flow chart for explaining a power transmission control method in a wireless power transmitter according to an embodiment of the present invention. 1 is a flowchart for

[0344] When the wireless power transmitter receives a negotiation request packet from the wireless power receiver, it sends an acknowledgement packet ( Grant Packet) and proceed to negotiation step 440.

[0345] Referring to FIG. 11, in a negotiation step 440, the wireless power transmitter detects a foreign object from the wireless power receiver. Status packet (FOD (Foreign Object Detection) Stat us Packet) can be received (S1110).

[0346] As an example, the wireless power transmitter may include a message field 1 as shown in FIG. 030 Reference Quality Factor Value ue, 1031) may be received.

[0347] Foreign object detection in negotiation step 440 is a procedure for comparing the measured value with a reference value received from a receiver. The reference and measured values ​​can be various types of parameters.

[0348] For example, the reference and measured values ​​may include resonant frequency, resistance, inductance, etc. is not limited to.

[0349] The wireless power transmitter 710 receives the stored measured peak frequency (PF_measured) and Using the measured quality factor value (Q_measured), the measured equivalent series resistance (Measure d ESR (Equivalent Series Resistance) _ measured ) can be calculated (S707).

[0350] Here, ESR is the series resistance component that is parasitic on the capacitor in the RLC series circuit. The actual capacitors and inductors used in the electrical circuits are called capacitance or inductance. However, when connected in series with a resistor, it becomes a very close approximation. The resistors can be considered as essentially ideal capacitors and inductors. The resistance is the equivalent series resistance ( is defined as the ESR.

[0351] The wireless power transmitter 710 receives a reference peak frequency (PF_reference) and Using the reference quality factor value (Q_reference), the reference equivalent series resistance (Refere nce ESR, ESR reference ) can be calculated (S708).

[0352] The wireless power transmitter 710 is _measured and ESR reference Use In one example, the wireless power transmitter 710 may detect a foreign object by detecting the foreign object (S709). S.R. reference and ESR _measured The ratio is compared with a predetermined critical value to determine whether the It is possible to determine whether or not a defect exists.

[0353] The wireless power transmitter sends an ACK or NACK response to the wireless power receiver depending on the result of the foreign object detection. can be transmitted to.

[0354] When a NACK response is received from the wireless power transmitter, the wireless power receiver determines that the wireless power transmitter Power is transmitted to the electronic device (or battery / load) through the output terminal until power transmission is completely stopped. It is possible to control the supply of power not exceeding a certain level. The above power may be based on 5W, but is not limited to this.

[0355] Below we will explain the relationship between ESR, quality factor value Q, and frequency.

[0356] Ideal RLC series circuit and TRF receiver (Tuned Radio Frequency The quality factor value Q at the ncy Receiver is calculated using the following formula 1:

[0357]

number

[0358] where R, L and C are storage, inductance and capacitance respectively.

number

number

[0359]

number

number

[0360] ESR is always an AC resistance measured at a standard frequency, and high ESR is caused by aging components, heat generation, and may increase the ripple current.

[0361]

number

[0362] Therefore, in the above embodiment, ESR reference teeth

number

number

[0363]

number

[0364]

number

[0365]

number

[0366]

number

[0367]

number

[0368] At this time, ESR referenc and ESR _measured The ratio is calculated as follows: It can be calculated.

[0369]

number

[0370]

number

[0371] The wireless power transmitter according to one embodiment has an ESR referenc and ESR _measured If the ratio exceeds a predefined ratio threshold, it is determined that a foreign object is present. Here, the ratio critical value can be determined by experimental results. For example,

number

[0372] In the following description, the wireless power transmitter is configured to measure the quality factor value and the determined quality factor critical value. The following description will focus on an embodiment in which the presence or absence of a foreign object is determined based on the above-mentioned.

[0373] The wireless power transmitter may determine whether or not a foreign object is present (S1120). After the wireless power transmitter detects an object in the selection step 410, the wireless power transmitter measures the The quality factor value determined based on the quality factor value received in the negotiation phase 440 and the reference quality factor value received in the negotiation phase 440. The presence or absence of a foreign object can be determined by comparing the critical values.

[0374] If the result of the determination is that no foreign object is present, the wireless power transmitter sends a first response signal to the corresponding wireless power receiver. Here, the first response signal may be an ACK signal. .

[0375] After transmitting the first response signal, the wireless power transmitter may perform a first power transmission control procedure (S11 40).

[0376] If it is determined in step 1120 that a foreign object is present, the wireless power transmitter transmits a second response signal. Here, the second response signal may be a NACK signal (S1150).

[0377] After transmitting the second response signal, the wireless power transmitter can perform a second power transmission control procedure (S11 60).

[0378] Here, the detailed configuration of the first power transmission control procedure and the second power transmission control procedure will be described later with reference to the drawings. This will become clearer through the explanation of

[0379] FIG. 12 illustrates a power transmission control method in a wireless power transmitter according to another embodiment of the present invention. 1 is a flowchart for

[0380] When the wireless power transmitter receives a negotiation request packet from the wireless power receiver, it sends an acknowledgement packet ( Grant Packet) and proceed to negotiation step 440.

[0381] Referring to FIG. 12, in a negotiation step 440, the wireless power transmitter detects a foreign object from the wireless power receiver. Status packet (FOD (Foreign Object Detection) Stat For example, the wireless power transmission The receiver sends the reference quality factor value in message field 1030 as shown in FIG. (Reference Quality Factor Value, 1031) The foreign object detection status packet can be received.

[0382] The wireless power transmitter can determine whether or not a foreign object is present (S1202). After the wireless power transmitter detects an object in the selection step 410, the wireless power transmitter measures the The quality factor value determined based on the quality factor value received in the negotiation phase 440 and the reference quality factor value received in the negotiation phase 440. The presence or absence of a foreign object can be determined by comparing the critical values.

[0383] If the result of the determination is that no foreign object is present, the wireless power transmitter sends a first response signal to the corresponding wireless power receiver. Here, the first response signal may be an ACK signal. .

[0384] When the wireless power transmitter receives the first response signal, the wireless power transmitter performs a first power transmission control procedure (S1140 ) can be accomplished.

[0385] The first power transmission control procedure (S1140) will be described in detail below.

[0386] If the wireless power transmitter determines that there is no foreign object, it sets the guaranteed power to the maximum power (Maximum m or potential power). For example, The maximum power may be 15W, but is not limited thereto, depending on the configuration and setting of the wireless charger. It may be larger depending on the total.

[0387] In the negotiation phase, the wireless power transmitter transmits a transmitter power capability packet containing the set guaranteed power. The wireless power receiver can then transmit the guaranteed power of the transmitter to the wireless power receiver. The required power can be determined within the

[0388] The wireless power transmitter is responsible for the guaranteed power (or required power) required by the wireless power receiver. The power supply control unit 100 can receive a guaranteed power packet including information on the power supply control unit 100 (S1204).

[0389] The wireless power transmitter can receive a negotiation end packet from the wireless power receiver (S1 205).

[0390] When the wireless power transmitter receives the negotiation end packet, the wireless power transmitter performs the correction step 450 in the negotiation step 440. can enter.

[0391] The wireless power transmitter may enter the correction step 450 to perform a correction procedure (S1206).

[0392] When the calibration procedure is completed, the wireless power transmitter enters the power transmission step 460 and starts charging. This can be done (S1207).

[0393] If it is determined in step S1202 that a foreign object is present, the wireless power transmitter enters a foreign object detection state. In response to the state packet, a second response signal can be transmitted (S1208). Here, the second response signal may be a NACK signal.

[0394] The wireless power receiver receives a second response signal as a response to the foreign object detection status packet. Then, a second power transmission control procedure (S1160) can be performed.

[0395] The second power transmission control procedure (S1160) will be described in detail below.

[0396] When the wireless power transmitter determines that a foreign object is present, the guaranteed power is set to the first power, i.e. In other words, the power can be transmitted by limiting it to a minimum guaranteed power (for example, 5 W) (S1209 ) The wireless power transmitter determines that a foreign object is present and sets the guaranteed power to 5W. The presence of a foreign object is detected based on a preset boundary value (or reference value) for power loss. Here, 5W is the maximum power that is predetermined between the transmitter and receiver. Because of its low power, the wireless power transmitter can set a solid reference value to judge foreign objects. Power loss-based foreign object detection methods and other foreign object detection methods may be applied. .

[0397] Here, the first power may be a guaranteed power corresponding to the first power transmission mode. The first power may be set to 5W, but is not limited to this, and may be set to a specific power less than 5W. At this time, it should be noted that the wireless power transmitter does not stop transmitting the wireless power signal. It must be noted.

[0398] The wireless power transmitter may receive a guaranteed power packet (S1210). The guaranteed power packet is determined by the wireless power receiver within the available guaranteed power of the wireless power transmitter. It may include information regarding the required power.

[0399] When the wireless power transmitter receives the negotiation end packet from the wireless power receiver, the wireless power transmitter enters the negotiation phase 44. 0, and proceed to the power transmission step (S460) to perform charging with the preset first power. Cut (S1212).

[0400] In the embodiment of FIG. 12, the wireless power transmitter performs the second power transmission control procedure (S1160). In the description, the guaranteed power packet and the negotiation end packet are received. This is only one embodiment. Other embodiments may be used to send guaranteed power packets and At least one of the negotiation termination packets may not be received.

[0401] The wireless power transmitter according to the embodiment of the present invention performs a second power transmission control procedure (S1160). It is not necessary to perform the correction step 450 during the process.

[0402] Here, the correction step 450 is for the transmission power, the reception power and the power loss between the transmitter and the receiver. The process of comparing the power transmitted by a transmitter with the power received by a receiver to accurately measure It can mean:

[0403] At this time, in the second power transmission mode, where the guaranteed power is 5W or more, the larger the transmission power, the Since the power loss may change, it is necessary to predict (calculate) this in advance and determine when the transmission power changes. By reflecting the predicted values ​​in advance, the power loss can be calculated more accurately. However, in the first power transfer mode, which sets the guaranteed power to the minimum of 5 W, Since the power is set as a target and the device is operated, a separate correction step 450 does not need to be performed. stomach.

[0404] In addition, when a foreign object is present, at least one of the transmission power, the reception power, and the loss power is When correcting for the effect of foreign matter, the correction is performed including the effect of foreign matter. This may increase the probability that the wireless power transmitter will determine that no foreign object is present even though the That is, the accuracy of the foreign object determination may be reduced.

[0405] In the present invention, a correction step 450 is performed during the second power transmission control procedure (S1160). By controlling so as not to cause this, the accuracy of foreign object detection can be improved.

[0406] FIG. 13 is a flow chart showing a power transmission control method in a wireless power transmitter according to still another embodiment of the present invention. 1 is a diagram for explaining the invention;

[0407] Referring to FIG. 13, the wireless power transmitter completes the second power transmission control procedure (S1160). Then, the power transmission step 460 can be started (S1310).

[0408] The wireless power transmitter receives the signal during the power transmission (i.e., charging) in the power transmission stage 460. The power loss is calculated based on the received power packet. The loss can be measured (or calculated or estimated) (S1320).

[0409] For the sake of convenience, the following description will be given assuming that the wireless power transmitter measures the power loss. This is merely one embodiment, and the results of transmission power measurement at the wireless power transmission stage and the results of transmission power measurement at the wireless power reception stage are shown in FIG. Note that the power loss can be calculated or estimated based on the received power measurements received from Must.

[0410] As an example, in the power transmission step 460, the wireless power receiver receives power for a predetermined period of time during charging. Based on the received power packet The power loss can be measured (or estimated) using the

[0411] Here, the power loss occurs when the wireless power receiver is not connected to a battery (or load). A first power loss measured based on a first received power value measured in a state Measured based on the second received power value measured while connected to a battery (or load) The second power loss may include at least one of the first and second power losses.

[0412] As an example, a wireless power transmitter may transmit a signal that indicates the received power for a predetermined period of time, which may be, for example, 10 minutes. Measure the power loss every time a packet is received and calculate the average (or maximum) of the measured power loss. The final power loss (either the smallest or the largest) can then be determined as the final power loss.

[0413] As another example, the wireless power transmitter may receive continuously after entering the power transmission stage 460. The power loss may be measured corresponding to N received power packets.

[0414] The wireless power transmitter can determine the presence or absence of a foreign object based on the measured power loss. Cut (S1330).

[0415] For example, the wireless power transmitter may be configured to: On the other hand, if the measured power loss is less than the predetermined power loss, it can be determined that a foreign object is present. If it is below the critical value, it can be determined that no foreign matter is present.

[0416] As another example, the wireless power transmitter may receive N consecutive power signals after entering the power transmission stage. The power losses estimated for the received power packets are all within a predetermined power loss threshold. If the value is within the critical value for a certain period of time, it can be determined that no foreign object is present. If the power loss is within a critical value after a certain period of time has elapsed, the device is deemed to be free of foreign objects. It is possible.

[0417] On the other hand, after entering the power transmission stage, a small number of N received power packets are continuously received. If the estimated power loss corresponding to at least one received power packet does not exceed a predetermined power loss threshold value, If exceeded, the wireless power transmitter can determine that a foreign object is present.

[0418] If it is determined that a foreign object is present, the wireless power transmitter stops power transmission and enters a selection stage. (S1340 and S1350).

[0419] If no foreign object is present as a result of the determination in step 1330, the wireless power transmitter proceeds to a renegotiation step. The wireless power receiver and the power transmission contract can be renegotiated by entering the wireless power receiver (S1360). ,The negotiated guaranteed power can be 5W or more.

[0420] The wireless power transmitter re-enters the power transmission step 460 according to the renegotiation result. After the renegotiation, the wireless power transmitter can continue to be charged. The charging device may perform charging by transmitting power between the first power and the second power. One power may be 5W and the second power may be 15W, but this is only one example. 2 The power intensity may be greater or less.

[0421] For example, if no foreign object is detected after entering the power transmission stage, the wireless power transmitter may By switching from the first power transmission mode to the second power transmission mode through negotiation, It can increase the strength of the force and shorten the charging time.

[0422] FIG. 14 is a flow chart showing a power transmission control method in a wireless power transmitter according to still another embodiment of the present invention. 1 is a drawing for explanation.

[0423] Referring to FIG. 14, the wireless power transmitter completes the second power transmission control procedure (S1160). Then, the power transmission step 460 can be started (S1410).

[0424] The wireless power transmitter can measure temperature changes during power transmission in the power transmission stage 460. (S1420).

[0425] As an example, during power transmission in the power transmission step 460, the wireless power transmitter The temperature change amount or the temperature change rate can be measured. The location where the change in temperature is measured may be, but is not limited to, the transmission coil of the transmission antenna 640. However, the present invention is not limited to this embodiment, and may be applied to other positions of the wireless power transmitter, for example, a wireless power transmitter, by the design of a person skilled in the art. The control circuit board and charging bed may be measured.

[0426] According to another embodiment, the wireless power transmitter measures the power transmitted by the wireless power receiver at a predetermined period. The wireless power transmitter may receive the temperature information from the wireless power receiver. The temperature change may be measured based on the temperature information.

[0427] A wireless power transmitter according to still another embodiment of the present invention is provided that detects a first temperature change and and based on a second temperature change measured based on the temperature information received from the wireless power receiver. The final temperature change may be determined.

[0428] The wireless power transmitter can determine the presence or absence of a foreign object based on the measured temperature change. In one example, the wireless power transmitter may determine whether the measured temperature change is a predetermined temperature change (S1430). If the critical value is exceeded, it can be determined that a foreign object is present.

[0429] On the other hand, if the measured temperature change is below a certain temperature change threshold, the wireless power transmitter is can be determined to be nonexistent.

[0430] If it is determined that a foreign object is present, the wireless power transmitter stops power transmission and enters a selection stage. (S1440 and S1450).

[0431] If no foreign object is present as a result of the determination in step 1430, the wireless power transmitter proceeds to a renegotiation step. The wireless power receiver may then renegotiate the power transmission contract with the wireless power receiver (S1460).

[0432] The wireless power transmitter re-enters the power transmission step 460 according to the renegotiation result to continue charging. It is possible to proceed.

[0433] For example, if no foreign object is detected after entering the power transmission stage, the wireless power transmitter may By switching from the first power transmission mode to the second power transmission mode through negotiation, It can increase the power intensity and shorten the charging time. The wireless power transmitter is a second power transmission In the transmission mode, the power can be transmitted between a first power and a second power, where the first power is The first power may be 5W and the second power may be 15W, but this is only one example. The second power may be It may be less than or greater than 15W depending on the design and configuration of the wireless power transmitter by those skilled in the art. .

[0434] FIG. 15 is a flow chart showing a power transmission control method in a wireless power transmitter according to still another embodiment of the present invention. 1 is a diagram for explaining the invention;

[0435] Referring to FIG. 15, the wireless power transmitter completes the second power transmission control procedure (S1160). Then, the power transmission step 460 can be started (S1510).

[0436] The wireless power transmitter receives a received power packet ( It is possible to measure the power loss of the Received Power Packet (S 1520).

[0437] As an example, in the power transmission step 460, feedback from the wireless power receiver during power transmission is The power is calculated based on the received power packet. The loss can be measured.

[0438] Here, the power loss occurs when the wireless power receiver is not connected to a battery (or load). A first power loss measured based on a first received power value measured in a state Measured based on the second received power value measured while connected to a battery (or load) The second power loss may include at least one of the first and second power losses.

[0439] The wireless power transmitter can determine the presence or absence of a foreign object based on the measured power loss. In one example, the wireless power transmitter may determine whether the measured power loss is a predetermined power loss (S1530). If the critical value is exceeded, it can be determined that a foreign object is present. If the power loss is less than a predetermined power loss threshold, it can be determined that no foreign object is present. do.

[0440] If it is determined that a foreign object is present, the wireless power transmitter stops power transmission and enters a selection stage. (S1540 and S1550).

[0441] If no foreign object is present as a result of the determination in step 1530, the wireless power transmitter performs power transmission step 4. The temperature change can be measured during power transfer at 60 (S1560).

[0442] As an example, during power transmission in the power transmission step 460, the wireless power transmitter The temperature change amount or the temperature change rate can be measured. The position where the change in temperature is measured may be around the transmitting coil, but is not limited thereto. may be measured at other locations of the wireless power transmitter depending on the design.

[0443] According to another embodiment, the wireless power transmitter measures the power transmitted by the wireless power receiver at a predetermined period. The wireless power transmitter may receive the temperature information from the wireless power receiver. The temperature change may be measured based on the temperature information.

[0444] According to yet another embodiment of the present invention, a wireless power transmitter includes: The second temperature change is measured based on the temperature information received from the wireless power receiver. The end temperature change may be determined.

[0445] The wireless power transmitter can determine the presence or absence of a foreign object based on the measured temperature change. In one example, the wireless power transmitter may determine whether the measured temperature change is a predetermined temperature change (S1570). If the critical value is exceeded, it can be determined that a foreign object is present.

[0446] On the other hand, if the measured temperature change is below a certain temperature change threshold, the wireless power transmitter is It can be determined whether or not it exists.

[0447] If it is determined that a foreign object is present, the wireless power transmitter stops power transmission and enters a selection stage. (S1540 and S1550).

[0448] If no foreign object is present as a result of the determination in step 1570, the wireless power transmitter proceeds to a renegotiation step. The wireless power receiver can then renegotiate the power transmission contract (S1580). The power transmitter re-enters the power transmission step 460 according to the renegotiation result and continues charging. It is possible.

[0449] For example, if no foreign object is detected after entering the power transmission stage, the wireless power transmitter may By switching from the first power transmission mode to the second power transmission mode through negotiation, It can increase the strength of the force and shorten the charging time.

[0450] In the embodiment of FIG. 15, the wireless power transmitter performs a foreign object detection procedure based on power loss. Then, the foreign object detection procedure based on the temperature change is performed according to the result of the judgment. However, this is merely one embodiment, and wireless power transmitters according to other embodiments may be used without being affected by temperature changes. Then, the foreign object detection procedure is performed based on the result of the judgment. The present invention may be embodied to perform the above-mentioned operations.

[0451] Figure 16a shows the wireless power transfer with foreign object detection when the transmitter and receiver versions are the same. 10 is a flowchart illustrating a transmission control method.

[0452] In the following description of the embodiment, the second version is a higher version than the first version. It should be noted that this is the more recently released version.

[0453] In detail, FIG. 16a shows the first embodiment in which the transmitter and receiver are both lower versions. 1 version - for example, 1.2V - and when they are the same, wireless power transfer control by foreign object detection 1 is a flowchart for explaining a method for controlling a wireless LAN in accordance with the WPC Qi standard. It may be a version for

[0454] Referring to FIG. 16a, upon entering the negotiation phase, the first version transmitter 1610 The FOD status packet can be received from the version receiver 1620 (S1601 ).

[0455] The first version transmitter 1610 detects the presence of a foreign object based on the received FOD status packet. If there is a foreign object, a NACK signal is sent to the first version receiver 1620. It can be transmitted (S1602).

[0456] The first version receiver 1620 receives a NACK response signal for the FOD status packet. Then, it is possible to transmit no packets or to transmit a specific packet (S1 603).

[0457] The first version transmitter 1610 transmits a NACK signal to the first version receiver 1620. When the power transmission is stopped, the power transmission can be interrupted within a certain period of time, for example, 5 seconds (S160 4). At this time, the first version transmitter 1610 receives from the first version receiver 1620 Any packets that are received can be ignored.

[0458] Figure 16b shows the wireless power transmission control by foreign object detection when the transmitter and receiver versions are different. 1 is a flowchart for explaining a control method.

[0459] In detail, Fig. 16b shows the result of the detection of a foreign object when the receiver is a higher version than the transmitter. 1 is a flowchart for explaining a line power transmission control method.

[0460] Referring to FIG. 16b, upon entering the negotiation phase, the first version transmitter 1630 The FOD status packet can be received from the version receiver 1640 (S1605 ).

[0461] The first version transmitter 1630 detects the presence of a foreign object based on the received FOD status packet. If a foreign object is detected, the second version receiver 1640 outputs a NACK signal. (S1606).

[0462] The first version receiver 1630 receives a NACK response signal for the FOD status packet. Then, the power transmitter capacity (PTC: Power Transmitter Capability) General Request Packet (GRP) containing information about Packet) to the first version transmitter 1630 (S1607 ).

[0463] The first version transmitter 1630 is a second version receiver 1630 having a higher version than itself. If the NACK signal is transmitted to 640, the received general request packet is ignored and the For example, power transmission can be interrupted within 5 seconds (S1608).

[0464] Figure 16c shows the wireless power transfer with foreign object detection when the transmitter and receiver versions are the same. 10 is a flowchart illustrating a transmission control method.

[0465] In detail, FIG. 16c shows the second version in which the receiver and transmitter versions are all higher versions. Explains how to control wireless power transmission by detecting foreign objects when the version is 1.3V. 1 is a flowchart for

[0466] Referring to FIG. 16c, upon entering the negotiation phase, the second version transmitter 1650 The FOD status packet can be received from the version receiver 1660 (S1609 ).

[0467] The second version transmitter 1650 detects the presence of a foreign object based on the received FOD status packet. If a foreign object is detected, the second version receiver 1660 outputs a NACK signal. (S1610).

[0468] The second version receiver 1660 receives a NACK response signal for the FOD status packet. Then, the power transmitter capacity (PTC: Power Transmitter Capability) General Request Packet (GRP) containing information about Packet) to the second version transmitter 1650 (S1611 ).

[0469] The second version transmitter 1650 receives the second version receiver 166 of the same version as itself. When a general request packet is received from 0, the power transmission function with the guaranteed power set to the first power The input packet may be transmitted to a second version receiver 1660 (S1612).

[0470] At this time, the second version receiver 1660 receives the special request power with the guaranteed power set to the first power. The packet may then be transmitted to a second version transmitter 1650 (S1613).

[0471] The second version transmitter 1650 transmits an ACK signal in response to a special request packet. Then, the power transmission step is entered and the guaranteed power is set to the first power to perform charging. Yes, it is possible (S1615).

[0472] In the wireless power transmitter according to the embodiment of FIG. 16c, a foreign object is detected during the negotiation stage. The advantage of this method is that even if the battery is turned off, the guaranteed power can be adjusted downward to maintain a safe charging state.

[0473] In the embodiment of FIG. 16c, if the second version transmitter 16 50 is a case where a special request packet is received in which the guaranteed power is set to a power greater than the first power. In this case, the second version receiver 1660 sends a NACK response as a response to the special request packet. can be transmitted to.

[0474] Figure 16d shows the wireless power transfer by foreign object detection when the transmitter is a higher version than the receiver. 10 is a flowchart illustrating a transmission control method.

[0475] In detail, Figure 16d shows that the receiver version is lower than the transmitter version. Backward compatibility when a first version - for example, 1.2V - is used. When a foreign object is detected, wireless power transmission is controlled to maintain compatibility. 1 is a flowchart illustrating a method.

[0476] Referring to FIG. 16d, upon entering the negotiation phase, the second version transmitter 1670 The FOD status packet can be received from the version receiver 1680 (S1616 ).

[0477] The second version transmitter 1670 detects the presence of a foreign object based on the received FOD status packet. If a foreign object is detected, the first version receiver 1680 outputs a NACK signal. (S1617).

[0478] As an example, the first version receiver 1680 may respond with a NACK to the FOD status packet. When the response signal is received, the power transmitter (PTC) is enabled. General Request Packet (GRP: General Request Packet) containing Capability information request Packet) to the second version transmitter 1670. (S1618). As another example, the first version receiver 1680 may be used depending on the type of receiver. When the FOD status packet is received as a NACK response signal, both packets are It is not necessary to transmit the version to the transmitter 1670 .

[0479] The second version transmitter 1670 is a first version receiver 16 that is a lower version than itself. When a NACK signal is transmitted from 80, the power transmission function with the guaranteed power set to the first power is The packet may be transmitted to a first version receiver 1680 (S1619).

[0480] As an example, the first version receiver 1680 may be configured with a special requirement that the guaranteed power be set to a first power. The request packet may be transmitted to the second version transmitter 1670 (S1620). As an example, depending on the type of receiver, the first version receiver 1680 may receive FOD status packets. When the second version transmitter 1 receives a NACK response signal for the first packet, both packets are It is not necessary to transmit to 670.

[0481] The second version transmitter 1650 sends a NACK signal in response to the special request packet. The transmission is performed for a certain period of time (S1621), which may be, but is not limited to, 5 seconds. - The power transmission can be interrupted within 100m. The second version transmitter 1650 is The first version receiver transmits a NACK signal in response to the packet. It is possible to block 1680 from entering the correction phase after the negotiation phase is completed.

[0482] The method according to the above-mentioned embodiment is implemented as a program for execution by a computer. The present invention can be stored in a computer-readable recording medium, and the computer-readable recording medium Examples include ROM, RAM, CD-ROM, magnetic tape, floppy disk, and optical data. This includes data storage devices, etc.

[0483] The computer-readable recording medium is connected to a computer system connected to a network. The computer readable code may be stored and executed in a distributed manner. And functional programs and codes for implementing the above-mentioned methods. The code segments are easily construed by a programmer skilled in the art to which the embodiments pertain. It is possible.

[0484] The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. It is obvious to one skilled in the art that this can be achieved.

[0485] Therefore, the above detailed description should not be construed as limiting in all respects, but as illustrative and The scope of the present invention should be determined by a reasonable interpretation of the appended claims. The scope of the present invention should be determined by the above-mentioned standard, and all modifications within the scope of the present invention are within the scope of the present invention. Included. [Industrial Applicability]

[0486] The present invention can be applied to a wireless power transmitting device that transmits wireless power to a wireless power receiving device.

Claims

1. a first packet receiving step of receiving a foreign object detection status packet; a first determination step of determining whether or not a foreign object is present based on the foreign object detection status packet before entering a first power transmission mode in which a first power is transmitted or a second power transmission mode in which a second power is transmitted; a power control step of controlling power based on the result of the first determination step; and The power control step includes: controlling in the first power transmission mode for transmitting the first power when it is determined that the foreign object is present as a result of the first determining step; and controlling in the second power transmission mode for transmitting the second power when it is determined that the foreign object is not present as a result of the first determining step; a second determination step of determining whether the foreign object is present in the first power transfer mode; the wireless power transmitter determines whether a foreign object is present before entering the first power transmission mode or the second power transmission mode; When no foreign object is present in the first determination step, the wireless power transmitter determines a magnitude of the second power through a correction step, and starts the second power transmission mode according to the second power. The wireless power transmitter starts the first power transmission mode at a fixed first power without performing the correction step when the foreign object is present in the first determination step. A method for controlling wireless power transmission of the wireless power transmitter.

2. the second power is greater than the first power; The method of claim 1 , wherein the power between the first power and the second power is increased or decreased based on a change in a power transmission environment in the second power transmission mode.

3. The method of claim 2 , wherein the first power is 5 W.

4. The method of claim 3 , wherein the second power is 15 W.

5. The second determination step includes: The method for controlling wireless power transmission of a wireless power transmitter according to claim 1 , further comprising determining whether the foreign object is present based on a transmission power loss.

6. The second determination step includes: measuring the strength of the transmitted power; receiving, from a wireless power receiver, strength information of received power corresponding to the transmission power; estimating a power loss based on a difference between the intensity of the transmission power and the intensity of the reception power; and The method of claim 5 , further comprising: comparing the estimated power loss with a preset power loss reference value to determine whether or not the foreign object is present.

7. If it is determined that the foreign object is present in the second determining step, power transmission is interrupted; The method of claim 1 , further comprising: changing the first power transmission mode to the second power transmission mode when it is determined that the foreign object is not present in the second determining step.

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