Wireless power transmission control method and device

Abstract

To provide a wireless power transmission control method that is capable of accurately detecting foreign objects located in a charging area, and can not only more effectively and accurately detect foreign objects but also minimize unnecessary charging interruptions.SOLUTION: A wireless power transmission control method for a wireless power transmitter includes: a first packet receiving step S1110 of receiving a foreign object detection status packet; a first determination step S1120 of determining whether a foreign object exists based on the foreign object detection status packet; and a power control step of controlling power based on a determination result in the first determination step. The power control step includes a first power transmission mode S1130 in which a first power is transmitted when it is determined that there is no foreign object as the determination result in the first determination step, and a second power transmission mode S1150 in which a second power is transmitted when it is determined that there is a foreign object as the determination result in the first determination step.SELECTED DRAWING: Figure 11

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 must be equipped with communication functions. A sensor with a built-in computer chip must be installed. Therefore, the power supply problem for these devices and sensors has become a new issue. as well as Bluetooth handsets and music players like iPods With the rapid increase in the number of types of portable devices, the task of charging batteries is becoming increasingly time-consuming for users. This has required time and effort. The technology has recently attracted interest.

[0004] Wireless power transmission technology wireless energy transfer) is a technology that uses the magnetic field induction principle to It is a technology for transmitting electrical energy from a transmitter to a receiver by a wire, and was first developed in the 1800s. Electric motors and transformers using the principle of magnetic induction began to be used, followed by high frequency and microwave. 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 using the electromagnetic induction principle. I'm electrified.

[0005] To date, the only wireless energy transmission methods are magnetic induction and magnetic resonance. Radiomagnetic Resonance (RF) and short-wavelength radio frequency (RF) 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 generates an electromotive force in other coils. This technology is rapidly being 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 drawbacks 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 within a limited distance and space. However, the drawback is that the energy transfer efficiency is somewhat low.

[0008] Short-wavelength wireless power transmission, or simply RF transmission, is a method of transmitting energy by radio waves (Radi This technology takes advantage of the fact that it 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. Recently, due to the efficiency improvement, research into commercialization is active. is progressing.

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

[0010] Do not allow any conductors (i.e., foreign objects (FO)) that are not wireless power receivers to be present in the wireless charging area. If an ign Object (FO) exists, the FO contains electromagnetic waves emitted from the wireless power transmitter. As an example, FO can be used on coins, paperclips, pins, buttons, etc. It may contain pens, etc.

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

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

[0013] Therefore, accurate detection of FOs located in the charging area is important in the field of wireless charging technology. 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, and the object of the present invention is to The present invention provides a method and apparatus for controlling wireless power transmission for wireless charging.

[0015] Another object of the present invention is to provide a wireless power transmitter that can detect foreign objects 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. The present invention provides a wireless power transmission control method and device that can prevent interruptions before they occur.

[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 whether or not a foreign object is present. Providing a wireless power transmitter that enables uninterrupted charging through adaptive transmission power control To do this.

[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 be apparent from the following description by those skilled in the art. 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 and determining whether a foreign object exists based on the foreign object detection status packet; a first determination step for determining whether or not the power is supplied to the power supply, and a second determination step for controlling the power supply based on the determination result of the first determination step; The power control step includes determining whether a foreign object is present in the first determining step. If a first power transmission mode is selected, the first power is transmitted. 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] Further, the wireless power transmission control method includes determining whether or not a foreign object is present in the first power transmission mode. The method may include a second determination step of:

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

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

[0027] The fourth determination step may further include measuring the temperature of 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] 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 The power transmission mode can be switched from the first power transmission mode to the second power transmission mode.

[0029] A method for controlling wireless power transmission of a wireless power transmitter according to another embodiment of the present invention includes: a first packet receiving step of receiving a packet and determining whether a foreign object exists based on the foreign object detection status packet; A first determination step for determining whether or not a foreign object is present, and a second determination step for determining whether or not a foreign object is present. If the first power is transmitted, it is determined that there is no foreign object in the first determining step. and 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 stage is to judge whether or not a foreign object is present based on the temperature change. It may include at least one fourth determination step for determining non-existence.

[0030] A wireless power transmitter according to yet another embodiment of the present invention includes an antenna for transmitting wireless power and a front 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 or not based on the foreign object detection status packet; If the presence of a foreign object is determined as a result of the primary determination, the first power If it is determined that there is no foreign object as a result of the first determination step, The power can be controlled to be transmitted between the first power and the second power.

[0031] Furthermore, the controller determines that a foreign object is present 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 transmission power loss. and a fourth determination based on temperature change to determine whether or not a foreign object is present. It is possible.

[0033] The wireless power transmitter also includes a sensor that measures the strength of the transmitted power and transmits the measured power to the controller. and wherein the third determination is performed by the controller based on the strength of the received power corresponding to the transmission power. and receiving the information through the demodulator, and calculating a difference between the intensity of the transmission power and the intensity of the reception power. and estimating the power loss based on the estimated power loss and a predetermined power loss criterion for a certain period of time. The presence or absence of foreign matter can be determined by comparing the standard values.

[0034] In addition, the sensor measures the temperature and transmits it to the controller, and the fourth determination is calculates a temperature change over a certain period of time based on the measured temperature, and 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 a foreign object is present as a result of the second determination step, the controller If it is determined that there is no foreign object as a result of the second determination step, the first power is supplied. The power can be controlled so that power is transmitted between the first power and the second power.

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

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

[0038] Here, the first power adjustment step

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

[0040] The first power may be 5W or less.

[0041] The second power may be 15W or less.

[0042] The wireless power transmission control method also includes a power supply that performs 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 determination step is

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

[0045] Here, the third judgment step is

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

[0047] In addition, 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 determination step is

[0050] Measuring the temperature of the charging area and determining a temperature change over a predetermined 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 or not a foreign object is present. The method may include determining whether or not

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

[0052] In addition, 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 charging; If the third determination step determines that a foreign object is present, the temperature change measured during charging is used as the basis for determining whether the foreign object is present. and a fourth determination step for determining whether or not a foreign object exists in the fourth determination step. If there is a problem, the power transmission for charging may be interrupted within the predetermined time.

[0054] The wireless power transmission control method further includes transmitting a response based on the determination result of the first determination step. the response is a response indicating the presence of a foreign object, and 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] In addition, 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 transmitting antenna for transmitting wireless power and a front a demodulator for demodulating the signal from the transmitting 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 received, The device adjusts the intensity of the wireless power based on the result of determining 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 a foreign object is detected as a result of the determination, the guaranteed power is increased from the second power to the first power. can be adjusted downwards.

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

[0061] Further, the controller determines whether or not a foreign object is present 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 is a sensor that transmits information about the strength of the transmission power to the controller. The controller further includes a sensor, and the controller receives information about the intensity of the transmitted power and the transmitted power during the charging. based on information about the strength of 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 results, it is possible to determine whether or not a foreign object is present.

[0064] In another aspect, the wireless power transmitter transmits information about 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 the temperature change calculated using the information, and 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 may be configured to change the charging status based on an estimated power loss during charging. and determining whether or not a foreign object is present, and if the determination based on the power loss indicates that a foreign object is present, and determining whether or not a foreign object is present based on the temperature change measured by the temperature sensor. 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 shows 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 that stores a program for executing the It is possible.

[0069] The above-described aspects of the present invention are merely a part of the preferred embodiments of the present invention, and are not intended to limit the scope of the present invention. Various embodiments incorporating 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 more apparent from and be understood in light of the following detailed description of the invention. [Effects 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 advantageously provides a method and apparatus for controlling wireless power transmission for wireless charging.

[0072] Furthermore, the present invention provides a wireless power transmitter that can detect foreign objects more accurately. There is.

[0073] In addition, the present invention minimizes foreign object detection errors, thereby preventing unnecessary interruptions to charging. It is advantageous to provide a method and apparatus for controlling wireless power transmission that can prevent this.

[0074] The present invention also prevents damage to equipment caused by foreign objects and adaptively controls transmission power depending on the presence or absence of foreign objects. It is advantageous to provide a wireless power transmitter that allows for uninterrupted charging through power control. do.

[0075] In addition, the present invention provides a wide range of stable wireless signals depending on the receiver type and power transmission environment. Advantageously, a wireless power transmitter capable of transmitting power can be provided.

[0076] The effects obtained from the present invention are not limited to those mentioned above, and may include other effects not mentioned above. 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 explanation 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] [Figure 2] FIG. 10 is a block diagram illustrating a wireless charging system according to another embodiment of the present invention.

[0079] [Figure 3] 1 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] FIG. 10 is a state transition diagram illustrating a wireless power transmission procedure according to an embodiment of the present invention.

[0081] [Figure 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 the 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 the prior art;

[0086] [Figure 10] 1 is a diagram illustrating a packet format according to an embodiment of the present invention;

[0087] [Figure 11] 1 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] 10 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] 10 is a diagram illustrating a method for controlling power transmission in a wireless power transmitter according to yet another embodiment of the present invention.

[0090] [Figure 14] 10 is a diagram illustrating a method for controlling power transmission in a wireless power transmitter according to yet another embodiment of the present invention.

[0091] [Figure 15] 10 is a diagram illustrating a method for controlling power transmission in a wireless power transmitter according to yet another embodiment of the present invention.

[0092] [Figure 16a] 10 is a flowchart illustrating a method for controlling wireless power transmission by detecting a foreign object when the transmitter and 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 the versions of a transmitter and a receiver are different.

[0094] [Figure 16c] 10 is a flowchart illustrating a method for controlling wireless power transmission by detecting a foreign object when the transmitter and receiver have the same version.

[0095] [Figure 16d] 10 is a flowchart illustrating 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 INVENTION

[0096] A wireless power transmission control method for a wireless power transmitter according to an embodiment includes receiving a foreign object detection status packet. 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 whether power is being supplied to a power supply; and a power control step for controlling power based on the determination result of the first determination step. The power control step is performed when it is determined that a foreign object is present in the first determining step. When the first power transmission mode is selected, the first power is transmitted. When the first determination step determines that there is no foreign object, the first power transmission mode is selected. The power transmission mode may include a second power transmission mode in which a second power is transmitted when it is determined that the second power is transmitted.

[0097] Hereinafter, the apparatus and various methods to which the embodiments of the present invention are applied will be described in more detail with reference to the drawings. The suffixes "module" and "module" for components used in the following description are used in the following description. The "section" is assigned or mixed with other sections only in consideration of the 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 explanation are Hardware components - e.g., circuit elements, microprocessors, memory, sensors, etc. However, this is only one example, and some functions of the relevant components may be Or it may be implemented entirely in software.

[0099] In the description of the embodiment, the components formed "above or below" each component are In the case of the word "no," "upper" or "lower" indicates that the two components are directly connected to each other. The two components are in close 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 is For convenience of explanation, the device will be referred to as a wireless power transmitter, a wireless power transmission device, a wireless power transmission device, Wireless power transmitter, transmission stage, transmitter, transmitting device, transmitting side, wireless power transmission device, wireless power In addition, the wireless power receiving device will be used in combination with the wireless power transmitter. For convenience of explanation, the term "wireless power receiving device" is used to refer to a device equipped with the function. Wireless power receiver, wireless power receiving device, wireless power receiver, receiving terminal, receiving side, receiving device The term "station," "receiver," etc. may be used interchangeably.

[0101] The transmitter according to the present invention may be in the form of a pad, a stationary 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 the 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 can be used. WPC (Wireless Power Consortium), the charging technology standard organization ) Power Matters Alliance (PMA) defined power standards Standard technologies may include, but are not limited to, magnetic induction.

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

[0104] The receiver according to the present invention may be a mobile phone, a smartphone, or the like. art phone, notebook 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 smartwatches. However, the present invention is not limited to this. Any device that can do this is sufficient.

[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 transmitting power wirelessly. 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 as

[0107] As an example, the wireless power transmitting stage 10 and the wireless power receiving stage 20 are used for wireless power transmission. In-band communication is used to exchange 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. 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 are used for wireless power transmission. Out-of-band (OUTB) is a method of exchanging information using a separate frequency band different from the operating frequency. In-band (IP) communication may be performed.

[0110] For example, information exchanged between the wireless power transmitting stage 10 and the wireless power receiving stage 20 is It may contain control information as well as status information.

[0111] Here, the state information and control information exchanged between the transmitting and receiving stages will be explained later in the description of the 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 transmitting stage 10 may be a wireless power receiving stage 2. It may also be one that transmits information only to 0.

[0114] The half-duplex communication method allows two-way communication between the wireless power receiving stage 20 and the wireless power transmitting stage 10. However, it has the characteristic that information can only be transmitted by one device at a time.

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

[0116] For example, the status information of the electronic device 30 may include current power usage information, identifying the application being executed, etc. 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 are not limited to this. Any information that can be used to control wireless power is acceptable.

[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 the fast charging mode of the connected wireless power transmitting stage 10. If it is confirmed that the electronic device 30 is in a state where the user is notified of the fact, the electronic device 30 can be notified of the fact.

[0119] The electronic device 30 displays the image through a predetermined display means, which may be a liquid crystal display, for example. It can be displayed that fast charging is possible depending on the device.

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

[0121] For example, as shown by reference numeral 200a, the wireless power receiving stage 20 may include a plurality of wireless power A plurality of wireless power receiving devices may be connected to one wireless power transmitting stage 10. Wireless charging may be performed using the same.

[0122] At this time, the wireless power transmitting stage 10 distributes power to the plurality of 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, The wireless power receiving device is configured to receive power from a plurality of wireless power receiving devices using different frequency bands allocated to each wireless power receiving device. 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 wireless It may also be configured as 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 transmission devices 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 have predetermined sensing capabilities to sense the presence of wireless power receivers through their respective transmitting coils. The signal 117, 127, e.g., a digital ping signal, is sent in a predefined order. Next, send it.

[0129] As shown in FIG. 3, the wireless power transmitter receives a first sensing signal as shown by reference numeral 110. The wireless power receiver 115 sequentially transmits the detection signal 117 through the signal transmission procedure. Signal Strength Indicator (116) received The transmit coils 111, 112 can be distinguished.

[0130] Next, the wireless power transmitter goes through the secondary sensing signal transmission procedure shown in drawing number 120. The signal strength indicator 126 is then transmitted from the transmit coil 111. , 112, the power transfer efficiency (or charging efficiency) - i.e., the efficiency of the transmitting coil and the receiving coil Identify the best transmit coil and transmit power through the identified transmit coil. The wireless charging can be controlled 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. 3 by reference numerals 110 and 120, 1. When the signal strength indicator 116, 126 is received by the second transmitting coil 112, the wireless power The transmitter receives the signal strength indicators of the first and second transmitting coils 111 and 112. Based on the indicator 126, select the best aligned transmit coil, and Wireless charging is performed using

[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 (Identification and Construction Phase Configuration Phase, 430), Negotiation Phase Phase (440), Calibration Phase (450), Power Transfer Phase (460) and Renegotiation It can be divided into a phase (Renegotiation Phase, 470).

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

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

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

[0138] If the transmitter senses that an object has been placed on the surface of the interface, it will start 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 Ar) on the surface of the interface, ea) where 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. It may sense the presence of an object in the active area on the surface of the base. .

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

[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 - which comprises:

[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 relative to a predefined reference operating frequency. .

[0146] As another example, the quality factor value may be set at 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 is configured to measure the maximum quality factor value within the operating frequency band. The frequency value corresponding to the quality factor value with the 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 referred to as the quality factor. Quality Factor Peak Frequency or For convenience of explanation, this will be simply called the peak frequency.

[0148] The distribution of the quality factor values ​​measured corresponding to the operating frequency band and the quality factor peak frequency 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 value may differ from the quality factor value measured on a commercial transmitter.

[0150] The wireless power transmitter identifies and configures itself when a signal strength packet is received in the ping step 420. The process may proceed to the formation 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] The wireless power transmitter also identifies the receiver type after successfully completing the identification and configuration procedure. The power transmission step 460 may then be entered (S406).

[0153] When the wireless power transmitter enters the negotiation stage 440, the wireless power transmitter receives a reference quality factor value from the wireless power receiver. 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 foreign objects. It is possible to determine whether or not a person is present.

[0156] However, the critical value of the predetermined 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 foreign objects by simply comparing the values ​​of the transmitters is applied to commercial transmitters. In this 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 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 used. Quality factor value corresponding to the operating frequency - hereinafter referred to as the current quality factor value for convenience of explanation - can be compared to determine whether or not a foreign object is present.

[0159] However, the reference quality factor value differs between the transmitter where it was measured - i.e., the authenticating transmitter - and the current quality The transmitters whose factor values ​​are measured may differ from each other. The determined quality factor critical value for the

[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 may be determined.

[0161] The inductance and / or current inside the transmitter coil may change due to changes in the surrounding environment. The series resistance component may decrease, which changes (shifts) the resonant frequency of the corresponding transmitting coil. 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 can be shifted.

[0162] For example, a wireless power receiver uses a magnetic shield with high magnetic permeability. Because it contains a high magnetic permeability, it can increase the inductance value measured by the transmitting coil. 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, and 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 may be configured to change the charging range 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 use the preset quality factor peak frequency - Hereinafter, for convenience of explanation, the "reference quality factor peak frequency (pf_reference)" will be used. or "reference peak frequency" - information about which is acquired 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 starts the ping phase 420. 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. To distinguish it from the frequency, we use the "measured quality factor peak frequency (pf_measured)" or is named the "measured peak frequency."

[0169] In 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 through a predetermined packet in the configuration step 430 or the negotiation step 440 .

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

[0172] A transmitter according to yet another embodiment of the present invention detects foreign objects based on a quality factor peak frequency. The presence or absence of foreign matter is determined by using all foreign matter detection methods based on the detection method and quality factor values. As an example, a reference quality factor value corresponding to a transmitter type and a measured quality factor may be If the comparison result shows that there is no significant difference between the two values ​​- for example, if 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 and 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 corresponding to the transmitter type The presence or absence of a foreign object may be determined by comparing the values.

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

[0175] When the transmitter detects an object, it enters the ping step 420 to wake up the receiver. up) and digital ping 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, the process may transition back to selection step 410 .

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

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

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

[0180] The receiver requests information about the transmitter type 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 if 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 (transm ission error), or no power transfer contract is set (no power transfer The process may proceed to a transfer contract selection step 410.

[0182] The transmitter identifies and configures the received configuration packet (Configurat Negotiation Field value of the ion packet Based on this, it can be determined whether or not entry into the negotiation stage 440 is necessary.

[0183] If the result of the check indicates that negotiation is necessary, the transmitter proceeds to negotiation step 440 to determine the desired FOD detection method. You can continue on.

[0184] On the other hand, if the confirmation result indicates that no negotiation is necessary, the transmitter immediately proceeds to the power transmission step 460. That's 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 confirmed that the receiver supports only one power transmission mode, the negotiation step 440 is performed. Instead, the power transfer step 460 can 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 can 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. The difference in the received power is compared with a predetermined reference value to determine whether or not a foreign object is present. 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 containing a reference quality factor value. FOD (Foreign Object Detection) Status P packet) or the reference peak frequency corresponding to the transmitter type. You can receive an FOD Status Packet containing a numerical value.

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

[0191] The transmitter is configured to determine the frequency of foreign object detection based on the reference quality factor peak frequency value corresponding to the transmitter type. A quality factor peak frequency threshold may be determined for the

[0192] The transmitter is configured to operate at a determined quality factor critical value and / or a determined quality factor peak frequency. The quality factor value measured as the critical value—means the quality factor value measured before the checking step 420 - and / or measuring the quality factor by comparing the peak frequency value with the foreign matter placed in the charging area It may be detected.

[0193] The transmitter can control power transmission depending on the foreign object detection result. If issued, the transmitter sends a negative response packet in response to the foreign object detection status packet. A negative acknowledge packet is sent to the receiver. This may result in, but is not limited to, an interruption of power transmission.

[0194] The transmitter transmits the determined quality factor peak frequency critical value and the measured quality factor peak frequency value. The transmitter can detect foreign objects placed in the charging area by comparing the results. For example, if a foreign object is detected, the transmitter can NACK in response to FOD Status Packet Sends a packet (Negative acknowledge packet) to the receiver This may result in, but is not limited to, an interruption of power transmission.

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

[0196] In another embodiment of the present invention, if 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 step 450, the power transmission step 460 may be entered (S407 and S409). .

[0198] In particular, if no foreign object is detected, the transmitter enters the correction stage 450 and the receiver receives the The strength of the power received is determined and the strength of the power transmitted by 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 receiver during power transmission. Based on this information, the transmitter can determine the strength of the received power to the receiver. In step 450, the 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 is not 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 proceeds to selection step 410 (S410).

[0201] In addition, in the power transmission step 460, the transmitter may change the 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 can revert to the power transfer stage 460. (S413).

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

[0203] The wireless power transmitter according to the embodiment of the present invention is configured to provide a guaranteed power required by the wireless power receiver. Based on the above, either 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 determination result of whether or not a foreign object is present. Therefore, 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. It 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 the second power transmission mode is set in the first power transmission mode. It may be larger than the guaranteed power that can be determined.

[0207] For 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, 15 W.

[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, the 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 transmit the measured quality factor value as, but not limited to, It can be saved in the internal memory (S502).

[0211] The wireless power transmitter 510 enters the ping stage and transmits the sensing signal in the same manner as described in FIG. The task can be carried out (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 packets and configuration packets (S504 and S5 05).

[0213] The wireless power transmitter 510 enters the negotiation stage and transmits a foreign object detection status packet to the wireless power receiver 5. 20 (S506). Here, the foreign object detection status packet is It can 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 exists or not can be determined (S507).

[0215] For example, the critical value may be determined to be a value that is 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 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 depending on 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. When this happens, the wireless power transmitter 510 will continue to operate at its output terminal until power transmission is completely stopped. The power supplied to the electronic device (or battery / load) through the 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 to this. 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 battery / load connected to the receiver 510.

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

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

[0222] The power supply 660 converts DC or AC power applied from the power source 650 into an input. For the sake of convenience, the following description will be made based on the power supply 660. The voltage supplied to the inverter 630 from the inverter input voltage or voltage 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 power according to 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 transistors A switch control method that converts AC power into DC power using a converter, filter, rectifier, etc. Here, the rectifier and filter are configured independently to provide an AC power supply. It may be placed 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 device or circuit element, It is widely used in many electronic devices and equipment due to its high efficiency, compact size and light weight. are.

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

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

[0228] On the other hand, switching mode generates almost no heat, is highly 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 can be used. (AC Power Supply) outputs AC voltage in the tens of Hz range. The converter then filters and rectifies the voltage to produce a DC voltage.

[0230] Variable SMPS can output a constant level DC voltage, The DC voltage output level is controlled by the Tx Controller. The variable SMPS is designed to keep the power amplifier of the wireless power transmitter in the saturation region where it is always highly efficient. The inverter 530 is configured to operate at a constant power level depending on the output power level of the power amplifier, i.e., the inverter 530. The supply voltage can be adjusted accordingly 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 allows the power amplifier to operate in the saturated region where it is 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 a 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) dulated) signal - converts a constant level DC voltage (V_rail) into an AC voltage By converting it, AC power can be generated 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 inverter 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, 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 is used to select a transmitting coil to be used for wireless power transmission from among multiple transmitting coils. A selection circuit (not shown) may also be included.

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

[0240] Also, the sensor 670 is connected to the transmitting controller 610 while the analog ping is being transmitted 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 placed in the charging area. The presence or absence of an object can be sensed.

[0241] When the wireless power transmitter 600 performs in-band communication with the wireless power receiver, 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] For example, the controller 610 may transmit a demodulated signal based on the demodulated signal received from the demodulator 680. Signal Strength Indicator (SSI) for digital ping You can check whether or not you have received a message.

[0244] When the controller 610 detects an object placed in the charging area in the selection step 410, the controller 610 performs the ping step. 420 to control the transmission of the digital ping 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 the 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 starts the digital ping transmission when the reception of the signal strength indicator is confirmed 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, if a foreign object is present in the charging area, the controller 610 stops power transmission and performs the selection step 4. You may enter 10.

[0249] In one embodiment, the controller 610 may receive a received signal strength packet from the wireless power receiver. The power loss on the wireless power transmission path can be calculated (or estimated) based on the control The detector 610 may determine whether or not a foreign object is present based on the calculated (or estimated) power loss. good.

[0250] In another embodiment, the controller 610 may also be configured to receive temperature sensing information from the sensor 670. or temperature changes can be measured based on temperature measurement information received from a wireless power receiver. The controller 610 may determine whether a foreign object is present based on the measured temperature change. .

[0251] In yet another embodiment, the controller 610 estimates the power loss and calculates the power loss based on the estimated power loss. The result of the judgment of the presence or absence of foreign matter based on the temperature change is used to judge the presence or absence of foreign matter. You may continue.

[0252] In yet another embodiment, the controller 610 determines whether a foreign object is present based on a temperature change. 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 stage 440, Determine a threshold value for foreign object detection based on the received FOD status packet, and The presence or absence of a foreign object may be determined based on the 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 can 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 termination packet containing a thermal code is received, the power transmission is stopped and the selection stage is 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 timer and beep signals can be suppressed. Then, the controller 610 enters the ping step 420 and transmits the digital signal through 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 code or overheat code is received, the ripping time After resetting the , the selection step 410 can be returned to.

[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 transmission mode. 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 supply is operated in either the first power transmission mode or 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 It may be larger than the maximum transmission power.

[0261] For example, the guaranteed power in the first power transmission mode is 5W or less, which is called the first power. The guaranteed power in the second power transfer mode may be 15W or less, which is referred to as 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 at the time of the power supply may be a value between the first power and the second power, but is not limited thereto, and can be any value within the range of the power supply used in the art. The guaranteed power corresponding to each operation mode may be set differently depending on the design of the user. You must be careful about this.

[0263] If a foreign object is present as a result of the determination of whether or not a foreign object exists in the negotiation step 440, the controller 61 0 indicates that the guaranteed power level is changed from the second level corresponding to the second power transmission mode to the first power transmission mode. You can change it 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 610 It can adjust the power downward. This prevents malfunction due to 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 can be controlled so that this does not happen.

[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 suffers from a problem of reduced accuracy.

[0267] Generally, the correction step 450 is a procedure performed under the assumption that no foreign matter is present. Therefore, if the correction step 450 is performed despite the presence of a foreign object in the charging area, the charge The foreign object detection method based on force loss has the problem of being unreliable due to its low accuracy.

[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, 610 can enter the renegotiation step 470 of FIG.

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

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

[0271] If the renegotiation result is 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 embodiments, 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 even though it is not present, charging can continue. This has the advantage of being

[0273] In particular, the wireless power transmitter 600 actually operates in a different mode while operating in the initial second power transmission mode. If a foreign object is detected even though no object is present, charging will be stopped immediately. 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] For example, the wireless power transmitter 600 may be configured to operate in a charging area where the wireless power receiver is placed without any foreign objects. Even if the transmitter coil and receiver coil are in a closed state, the alignment between them may cause foreign objects to be trapped in the charging area. It may be assumed that it exists.

[0275] The wireless power transmitter 600 according to the present invention can detect additional foreign objects even after switching to the first power transmission mode. By carrying out the detection procedure, there is an advantage that foreign objects can be detected more accurately. Additional foreign object detection procedures are power loss based foreign object detection and temperature change based foreign object detection. The method may include at least one of the following foreign object detection procedures:

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

[0277] Referring to FIG. 7, the transmit 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 transmit 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 device 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 connected to the 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 the coil selection circuit 71. 0, and the other end may be connected 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 diagram illustrating a wireless power supply linked to the wireless power transmitting apparatus according to an embodiment of the present invention. FIG. 2 is a block diagram illustrating 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 signal transmitted through the receiving antenna 810 to the The AC power can be converted to DC power and transmitted to a DC / DC converter 830 .

[0288] The DC / DC converter 830 adjusts the output DC power intensity of the rectifier 820 to that required by the load 850. The DC power can be converted to a specific intensity.

[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 the section 880.

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

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

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

[0293] For example, the main control unit 880 may compare the measured intensity of the output DC power of the rectifier with 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 that an overvoltage has occurred through the modulation unit 870. It can be transmitted to a line power transmitter 600.

[0294] When a packet is received 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 determine the received packets. At this time, the wireless power transmitter 600 can generate an amplitude modulation signal corresponding to the wireless power receiver. 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 frequency packet.

[0296] The modulator 870 according to an embodiment receives an AC power signal through the receiving antenna 810. In this case, the main control unit 880 may be provided with a modulation switch for amplitude modulation of 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 can 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. , a signal strength packet corresponding to the corresponding sensing signal is transmitted via the modulation unit 870 via wireless power transmission. The information can be controlled so that it can be transmitted to the machine.

[0298] For example, the main control unit 880 may turn on the switch 840 when the internal temperature exceeds a predetermined reference value. By controlling, for example, by switching OFF, the output DC power of the DC / DC converter 830 is supplied to the load 85 In this case, the main control unit 880 may control the overheat code not to be 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 configured as a controller inside an electronic device in which the wireless power receiver 800 is installed. Power management elements that control power - for example, PMIC (Power Management It can be linked with IC.

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

[0301] The power management elements can provide battery state of charge 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 foreign object detection An outgoing status packet can 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 corresponds to the reference quality factor value and the corresponding wireless power receiver. The resonant frequencies may include:

[0305] As another example, the foreign object detection packet may include a resonance frequency and a product corresponding to the resonance 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 receives the power transmitted by the wireless power transmitter 600. The device 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 performed based on the packet transmission time and the wireless power supply time of the wireless power transmitter. It may be a 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 whether or not a foreign object is detected in a wireless power transmitter. 1 is a diagram 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) to enter negotiation stage 440.

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

[0312] As an example, the wireless power transmitter may include a message field as shown in FIG. 10 below. Reference Quality Factor Value (QFV) 1031).

[0313] The wireless power transmitter can determine whether or not a foreign object exists (S902). The line power transmitter is measured after object detection in the selection step 410 and before entering the ping step 420. The quality factor determined based on the quality factor value and the reference quality factor value received in the negotiation stage 440. The presence or absence of foreign matter can be determined by comparing the critical values.

[0314] In the following example, a method for detecting foreign matter after entering the negotiation stage 44 is to use the quality factor value. However, this is only one example and is subject to negotiation. Those skilled in the art will recognize that different methods for detecting foreign matter may be applied depending on the design or standard definition. You must be careful about this.

[0315] If the result of the judgment shows that there is no foreign object, the wireless power transmitter sends an ACK signal to the corresponding wireless power receiver. The data 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, it performs the correction step 450 in the negotiation step 440. can enter.

[0319] The wireless power transmitter may enter the correction step 450 and 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. A NACK signal can be transmitted as a response to the state packet (S908).

[0322] The wireless power receiver receives a NACK signal as a response to the foreign object detection status packet. and the power signal received from the wireless power transmitter is completely removed. The power must not exceed a predetermined threshold, which may be, but is not limited to, 5W. It can be controlled so that

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

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

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

[0326] Therefore, when a conventional wireless power transmitter determines that a foreign object is present, it Blocking access to floor 460 and interrupting power transmission within a predefined time period. Selection step 410 is 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 and receiving coils - i.e., Z d distance—and the position of the wireless power receiver placed in the charging area—i.e., XY Displacement - etc., a foreign object is present 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. Attributing it to the user can cause serious inconvenience to the user.

[0329] In particular, wireless power receivers used in smartphones and other devices are designed to reduce the thickness of the product. To prevent 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 even 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. Even though the object is placed in the specified area, the quality factor Q is measured low and the object is judged to be a foreign object. This can also include situations where both the smartphone and the device are 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 need for a method of controlling power transmission in a wireless power transmitter that can prevent power loss and minimize user inconvenience. are.

[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 in-band. Although packets can be exchanged via out-of-band communication, this is only one example. The relevant packets may be exchanged accordingly.

[0336] Referring to FIG. 10, the wireless power transmitter stage 10 and the wireless power receiver stage 20 are used for information exchange. The packet format 1000 is used for synchronization acquisition for demodulation of the corresponding packet and for Preamble (101) to identify the exact start bit of the packet 0) field, a header ( 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 packet. sum, 1040) fields.

[0337] The packet receiving stage receives 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 each stage in FIG. 4 are defined by the value of header 1020. 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 as End Power Tr to stop 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, it is not limited to this.

[0340] The packet format 1000 according to another embodiment of the present invention is Transmitting stage identification information for identifying the transmitting stage, and for identifying the receiving stage that will receive the corresponding packet. The receiving stage identification information may further include at least one of the following:

[0341] Here, the sender identification information and the receiver identification information are IP address information, MAC (Medi um Access Control) can include address information, product identification information, etc. However, the information is not limited to this and can distinguish between 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 in which the corresponding packet is multiplexed. If the signal must be received by multiple devices, a designated It may further include a fixed group identification information.

[0343] FIG. 11 is a flow chart illustrating 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) to enter negotiation stage 440.

[0345] Referring to FIG. 11, in negotiation step 440, the wireless power transmitter receives a foreign object detection signal 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 send a message in message field 1 as shown in FIG. Reference Quality Factor Value ue, 1031).

[0347] Foreign object detection in the negotiation step 440 is a procedure of comparing the measured value with a reference value received from the 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 Measured equivalent series resistance (ESR) using the measured quality factor (Q_measured) d ESR (Equivalent Series Resistance) _ measured ) can be calculated (S707).

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

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

[0352] The wireless power transmitter 710 has an ESR _measured and ESR reference Use As an example, the wireless power transmitter 710 may be SR reference and ESR _measured The ratio is compared with a predetermined critical value to determine whether foreign matter It is possible to determine whether or not a

[0353] The wireless power transmitter sends an ACK or NACK response to the wireless power receiver depending on the foreign object detection result. 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 power supply so that it does not exceed 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 Q, and frequency.

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

[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 a high ESR is caused by aging, heating, or other 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 critical ratio, it is determined that a foreign object is present. Here, the critical ratio 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 determine the critical quality factor value. The following description will focus on an embodiment in which the presence or absence of a foreign substance is determined based on the above.

[0373] The wireless power transmitter may determine whether or not a foreign object is present (S1120). After detecting an object in the selection step 410, the wireless power transmitter measures the The quality factor values ​​determined based on the quality factor values ​​received in the negotiation stage 440 and the reference quality factor values ​​received in the negotiation stage 440. The presence or absence of foreign matter 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. (S1130), where the first response signal may be an ACK signal. .

[0375] After transmitting the first response signal, the wireless power transmitter can 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.

[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) to enter negotiation stage 440.

[0381] Referring to FIG. 12, in negotiation step 440, the wireless power transmitter receives a foreign object detection signal 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. 10 below. (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 detecting an object in the selection step 410, the wireless power transmitter measures the The quality factor values ​​determined based on the quality factor values ​​received in the negotiation stage 440 and the reference quality factor values ​​received in the negotiation stage 440. The presence or absence of foreign matter 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. (S1203). Here, the first response signal may be an ACK signal. .

[0384] When the first response signal is received, the wireless power transmitter performs a first power transmission control procedure (S1140 ) can be carried out.

[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, but is not limited to, 15W, depending on the configuration and setting of the wireless charger. The total may be larger.

[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. The required power can be determined within the

[0388] The wireless power transmitter must be able to determine the guaranteed power (or required power) required by the wireless power receiver. The power supply unit 100 can receive a guaranteed power packet including information on the power supply 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, it 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 the 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 in 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, it sets the guaranteed power to the first power, i.e., That is, power can be transmitted while being limited to a minimum guaranteed power (for example, 5W) (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 consumption, the wireless power transmitter can set a solid reference value to determine whether a foreign object is present. Foreign object detection methods based on power loss and other 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, please note that the wireless power transmitter does not stop transmitting the wireless power signal. This must be considered.

[0398] The wireless power transmitter can 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 power requirements.

[0399] When the wireless power transmitter receives the negotiation end packet from the wireless power receiver, the wireless power transmitter proceeds to the negotiation stage 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). Although the guaranteed power packet and negotiation end packet are described in the description, This is only one embodiment, and other embodiments may be implemented by providing a wireless power transmitter with a guaranteed power packet 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). Correction step 450 may not be performed during this time.

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

[0403] In this case, in the second power transmission mode, where the guaranteed power is 5W or more, the larger the transmission power, the Since power loss can change, it is necessary to predict (calculate) this in advance and adjust it accordingly when the transmission power changes. By reflecting the predicted value 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 5W, Since the power is set as a target, 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 made 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 object is present. That is, the accuracy of foreign matter determination may be reduced.

[0405] In the present invention, the correction step 450 is performed during the second power transmission control procedure (S1160). By controlling the amount of foreign matter to be detected, the accuracy of foreign matter detection can be improved.

[0406] FIG. 13 is a flow chart illustrating a method for controlling power transmission in a wireless power transmitter according to another embodiment of the present invention. 1 is a diagram for explanation.

[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 entered (S1310).

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

[0409] For convenience of explanation, the following description will be given assuming that the wireless power transmitter measures the power loss. This is only one example, and the transmission power measurement result at the wireless power transmitting stage and the wireless power receiving stage 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 time during charging. Based on the received power packet The power loss can be measured (or estimated) using

[0411] Here, the power loss is the loss when the wireless power receiver is not connected to the battery (or load). The first power loss measured based on the first received power value measured in the 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 second power losses.

[0412] As an example, a wireless power transmitter may receive power for a predetermined period of time, which may be, for example, 10 minutes. The power loss is measured every time a packet is received, and the average (or maximum) of the measured power loss is calculated. The final power loss (either the smallest or largest value) can 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 the 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 subcritical value, it can be determined that no foreign matter is present.

[0416] As another example, the wireless power transmitter may receive N consecutive signals after entering the power transmission stage. The power losses estimated corresponding to the received power packets are all within a predetermined power loss threshold. If the value is within the critical value for a specific time, it can be determined that no foreign matter is present. If the power loss is within the critical value after a certain time has elapsed, it is determined that there is no foreign object. 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 power loss estimated 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 the result of the judgment indicates that a foreign object is present, the wireless power transmitter stops power transmission and enters the 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 the renegotiation step. The wireless power receiver and the power transmission contract can be renegotiated (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 and transmits the power to the corresponding wireless power receiver. After the renegotiation, the wireless power transmitter can continue to be charged. The charging can be performed by transferring 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 a foreign object is not detected after entering the power transmission stage, the wireless power transmitter By switching from the first power transmission mode to the second power transmission mode through negotiation, the transmission power Increases power intensity and reduces charging time.

[0422] FIG. 14 is a flow chart illustrating a method for controlling power transmission in a wireless power transmitter according to still another embodiment of the present invention. 1 is a diagram 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 entered (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 temperature change is measured may be, but is not limited to, the transmitting coil of the transmitting antenna 640. However, other positions of the wireless power transmitter, for example, a position provided in the wireless power transmitter, may be provided 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, a wireless power transmitter measures power at a predetermined period by a wireless power receiver during power transmission. The wireless power transmitter may receive the temperature information received from the wireless power receiver. The temperature change may be measured based on the temperature information.

[0427] A wireless power transmitter according to yet another embodiment of the present invention is configured to measure 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. For 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 the predetermined temperature change threshold, the wireless power transmitter detects the presence of a foreign object. can be determined to be non-existent.

[0430] If the result of the judgment indicates that a foreign object is present, the wireless power transmitter stops power transmission and enters the 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 the renegotiation step. The wireless power receiver can then renegotiate the power transmission contract (S1460).

[0432] The wireless power transmitter re-enters the power transmission step 460 according to the renegotiation result and continues charging. You can proceed.

[0433] For example, if a foreign object is not detected after entering the power transmission stage, the wireless power transmitter By switching from the first power transmission mode to the second power transmission mode through negotiation, the transmission power The wireless power transmitter can increase the power intensity and shorten the charging time. 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. It may be less than or greater than 15W depending on the design and configuration of the wireless power transmitter by a person skilled in the art. .

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

[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 entered (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 is the loss when the wireless power receiver is not connected to the battery (or load). The first power loss measured based on the first received power value measured in the 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 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 equal to 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 below a predetermined power loss threshold, it can be determined that no foreign object is present. do.

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

[0441] If there is no foreign object as a result of the determination in step 1530, the wireless power transmitter proceeds to 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 temperature change is measured may be around the transmitting coil, but is not limited thereto, and those skilled in the art will appreciate. It may also be measured at other locations on the wireless power transmitter depending on the design.

[0443] According to another embodiment, a wireless power transmitter measures power at a predetermined period by a wireless power receiver during power transmission. The wireless power transmitter may receive the temperature information received 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 final 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. For example, the wireless power transmitter may determine whether the measured temperature change is equal to or exceeds 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 the predetermined temperature change threshold, the wireless power transmitter detects the presence of a foreign object. It can be determined whether or not it exists.

[0447] If the result of the judgment indicates that a foreign object is present, the wireless power transmitter stops power transmission and enters the 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 the renegotiation step. The wireless power receiver and the power transmission contract can be renegotiated (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 a foreign object is not detected after entering the power transmission stage, the wireless power transmitter By switching from the first power transmission mode to the second power transmission mode through negotiation, the transmission power Increases power intensity and reduces 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 only one embodiment, and wireless power transmitters according to other embodiments may be affected by temperature changes. After performing the foreign object detection procedure based on the power loss, the foreign object detection procedure is performed based on the result of the determination. It may be implemented to perform the following.

[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 example where the transmitter and receiver versions 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 illustrating a control method according to the WPC Qi standard. It can 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 specific packets (S1 603).

[0457] The first version transmitter 1610 transmits a NACK signal to the first version receiver 1620. When the power is transmitted, the power transmission can be interrupted within a certain 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 sent 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 illustrating a control method.

[0459] In detail, Figure 16b shows the effect of foreign object detection when the receiver is a higher version than the transmitter. 10 is a flowchart illustrating 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 determines the presence of a foreign object based on the received FOD status packet. If a foreign object is detected, the second version receiver 1640 sends a NACK signal to the (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) can be transmitted 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 a 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, for example. 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 determines the presence of a foreign object based on the received FOD status packet. If a foreign object is detected, the second version receiver 1660 sends a NACK signal to the (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) can be transmitted 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 the second version receiver 1660 (S1612).

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

[0471] The second version transmitter 1650 transmits an ACK signal in response to the special request packet. (S1614) and enters the power transmission stage, sets the guaranteed power to the first power, and performs 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. Even if the battery is overheated, 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 diagram showing 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 in response to the special request packet. can be transmitted to.

[0474] Figure 16d shows the wireless power transmission 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 there is a first version - for example, 1.2V Controlling wireless power transmission when a foreign object is detected 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 determines the presence of a foreign object based on the received FOD status packet. If a foreign object is detected, the first version receiver 1680 sends a NACK signal. (S1617).

[0478] As an example, the first version receiver 1680 may respond to a NACK with an FOD status packet. When the response signal is received, the power transmitter (PTC) is activated. General Request Packet (GRP) containing Capability information request Packet) to the second version transmitter 1670. (S1618). As another example, depending on the type of receiver, the first version receiver 1680 When the FOD status packet is received, the NACK response signal is sent to the It does not have to be transmitted to the version transmitter 1670 .

[0479] The second version transmitter 1670 is a first version receiver 1670 of a lower version than itself. When a NACK signal is transmitted from 80, the power transmission function whose guaranteed power is set to the first power is The packet can 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 can be transmitted to the second version transmitter 1670 (S1620). As an example, depending on the receiver type, the first version receiver 1680 may receive FOD status packets. When the second version transmitter 1 receives a NACK response signal for each packet, It does not have to be transmitted to 670.

[0481] The second version transmitter 1650 sends a NACK signal in response to the special request packet. The transmission is performed (S1621) for a certain period of time, for example, 5 seconds, but is not limited thereto. -The power transmission can be interrupted within 2 hours. The second version transmitter 1650 is Version 1 receivers transmit a NACK signal in response to a packet. 1680 can be blocked from entering the correction phase after the negotiation phase is completed.

[0482] The method according to the above-described embodiment is implemented as a program to be executed by a computer. The computer-readable recording medium may be stored in 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. and 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 those skilled in the art that this can be done.

[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 considered as follows: The scope of the present invention is to be determined by the present invention itself, 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 power receiving method for a wireless power receiver, comprising: a signal transmitting step of transmitting a signal including the FOD status packet to a wireless power transmitter; a power receiving step in which, when a NAK response indicating that a foreign object is present in a charging area of ​​the wireless power transmitter is received from the wireless power transmitter as a response to the FOD status packet, a first power is transmitted, or, when an ACK response indicating that the foreign object is not present in the charging area of ​​the wireless power transmitter is received from the wireless power transmitter, a second power is transmitted from the wireless power transmitter; a signal strength packet transmitting step of transmitting a signal strength packet to the wireless power transmitter for calculating or estimating a power loss used to determine whether the foreign object is present in the charging area; Including, the intensity of the second power is greater than the intensity of the first power; The wireless power transmitter determines whether there is a foreign object before entering a power transmission stage; the wireless power receiver starts receiving a fixed first power as a first power when the wireless power transmitter determines that the foreign object is present, or starts receiving a negotiated second power as a second power when the wireless power transmitter determines that the foreign object is not present; Power receiving method.

2. 2. The method of claim 1, further comprising the step of: modulating a signal containing the FOD status packet before the signal transmitting step.

3. The power receiving method according to claim 1 or 2, further comprising the step of measuring the strength of the wireless power transmitted from the wireless power transmitter after the power receiving step.

4. the FOD status packets include a first FOD status packet and a second FOD status packet; the first FOD status packet includes a reference quality factor or a reference peak frequency; The power receiving method of claim 1 , wherein the second FOD status packet includes one of the reference quality factor and the reference peak frequency that is different from that of the first FOD status packet.

5. The power receiving method of claim 4, wherein the first power is transmitted to the wireless power receiver when a NAK response to at least one of the first FOD status packet and the second FOD status packet is received from the wireless power transmitter.

6. The power receiving method of claim 4 , wherein the second power is transmitted to the wireless power receiver when an ACK response to the first FOD status packet and the second FOD status packet is received from the wireless power transmitter.

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