Method for detecting foreign substances and device and system therefor

Abstract

To provide a method for detecting foreign material in a wireless power transmitter allowing more effective and accurate detection of the foreign material, and an apparatus and a system therefor.SOLUTION: The method comprises the steps of: measuring a quality factor value, which corresponds to a reference operation frequency, when an object is sensed; searching for a current peak frequency having a maximum quality factor value within an operation frequency band; receiving, from a wireless power receiver, a foreign material detection state packet including information on a reference peak frequency; correcting the measured quality factor value by using a difference value between the current peak frequency and the reference peak frequency; and determining whether the foreign material exists by comparing the corrected quality factor value with a predetermined quality factor threshold value.SELECTED DRAWING: Figure 13a

Description

[Technical field]

[0001] The present invention relates to a wireless power transmission technology, and more particularly to a wireless power transmitter that is located in the charging area. The present invention relates to a method for detecting foreign substances, and an apparatus and system therefor. [Background technology]

[0002] In recent years, with the rapid development of information and communication technology, a ubiquitous society based on information and communication technology is emerging. This holds true.

[0003] In order to connect information and communication devices anytime and anywhere, all facilities in society need to be equipped with communication capabilities. The vehicle must be fitted with a sensor that contains a computer chip that can read the information. As a result, the power supply problem for these devices and sensors has become a new issue. Not just talk, but a Bluetooth handset and an iPod-like music player As the variety of portable devices such as smartphones and tablets rapidly increases, the task of charging the battery becomes more and more time-consuming for users. Wireless power transmission technology is the best way to solve these problems. There is recent interest.

[0004] Wireless power transmission technology (WPT) Wireless energy transfer (IREWET) is a technology that uses the principle of magnetic field induction to transmit information wirelessly. It is a technology for transmitting electrical energy from a transmitter to a receiver, and was first developed in the 1800s using electromagnetic induction. Electric motors and transformers using the principle of microwaves began to be used. Ave, methods have also been tried that involve transmitting electrical energy by emitting electromagnetic waves such as lasers. The electric toothbrushes and some wireless razors we use often are actually powered by the electromagnetic induction principle. Be electrified.

[0005] To date, wireless energy transmission methods can be broadly divided into magnetic induction and magnetic resonance (El Using the ectromagnetic resonance method and short wavelength radio frequency They can be classified into RF transmission methods, etc.

[0006] The magnetic induction method involves placing two coils next to each other and then passing a current through one coil. The magnetic flux generated at this time induces an electromotive force in the other coil. This technology uses the phenomenon known as magnetic field, and has been quickly commercialized in small devices such as mobile phones. The air induction system can transmit up to several hundred kilowatts (kW) of power and is highly efficient. However, since the maximum transmission distance is less than 1 centimeter (cm), it is generally There is a drawback to having to be placed next to it.

[0007] The magnetic resonance method uses electric or magnetic fields instead of electromagnetic waves or currents. The magnetic resonance method is hardly affected by electromagnetic waves, so it is not affected by other electronic devices or the human body. On the other hand, it can only be used at a limited distance and in a limited space. However, it has the disadvantage 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 (Ra This is based on the fact that it can be sent and received directly in the form of a digital wave. This technology is an RF wireless power transmission method that uses a rectenna. Rectenna is a compound word of antenna and rectifier. It means an element that converts RF power directly into DC power. In other words, the RF method is different from AC radio. This technology converts waves into DC and uses them. As efficiency has improved recently, research is being conducted for commercialization. Research is actively ongoing.

[0009] Wireless power transmission technology is not only used in mobile devices, but also in other industries such as IT, railways, and home appliances. It can be used in a variety of ways.

[0010] There is no conductor in the wireless charging area that is not a wireless power receiver, i.e., Foreign O When a target object is present, the electromagnetic signal emitted from the wireless power transmitter is induced in the FO. As an example, FO can be used to heat copper coins, paperclips, pins, balls, etc. This may include a pen.

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

[0012] Therefore, accurate detection of FOs located in the charging area is important in the field of wireless charging technology. This has become a major issue. Summary of the Invention [Problem to be solved by the invention]

[0013] 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 for detecting foreign matter in wireless charging, and an apparatus and system therefor. do.

[0014] Another object of the present invention is to provide a method for determining whether a current peak frequency is shifted from a reference peak frequency. Dynamically correcting the quality factor values ​​measured during substance detection allows for more accurate detection of foreign substances. The present invention aims to provide a method and device for detecting foreign substances that can detect foreign substances.

[0015] It is yet another object of the present invention to provide a method for determining the start frequency and the current peak frequency within the operating frequency band. The quality factor slope is calculated based on the output voltage level, and the quality factor slope is compared with a predetermined quality factor slope critical value. A foreign substance detection method and method therefor that can detect foreign substances more accurately by comparing with the above. The present invention provides an apparatus and system for

[0016] It is yet another object of the present invention to provide a method for determining the start frequency and the current peak frequency within the operating frequency band. A quality factor slope is calculated based on the quality factor values ​​and compared to a predetermined quality factor slope critical value. A method for detecting foreign substances that can detect foreign substances more accurately by comparing the The present invention provides an apparatus and system.

[0017] Another object of the present invention is to provide a method for detecting foreign substances based on quality factor and a method for detecting foreign substances based on peak frequency. By adaptively applying the foreign substance detection method, the foreign substance detection capability can be improved. A method for detecting a substance and an apparatus and system therefor are provided.

[0018] It is still another object of the present invention to detect foreign matter based on the direction of movement of the peak frequency. The present invention provides a method for detecting foreign substances and an apparatus and system therefor.

[0019] The technical problems to be solved by the present invention are not limited to the above-mentioned technical problems. Further technical problems that have not been solved will become apparent to those skilled in the art from the following description. This will be clearly understandable to those who have [Means for solving the problem]

[0020] The present invention can provide a method for detecting foreign substances and an apparatus and system therefor.

[0021] According to an embodiment of the present invention, a method for detecting a foreign object in a wireless power transmitter includes: measuring a quality factor value corresponding to a reference operating frequency; and measuring a quality factor value corresponding to the reference operating frequency band. A step of searching for a current peak frequency having a maximum value and a step of receiving information about a reference peak frequency receiving a foreign object detection status packet including the current peak from a wireless power receiver; and correcting the measured quality factor value using a difference value between the frequency and the reference peak frequency. and comparing the corrected quality factor value with a predetermined quality factor critical value to determine whether or not a foreign substance is present. and determining whether or not

[0022] Here, the foreign substance detection status packet further includes a reference quality factor value, A threshold value is determined based on the reference quality factor value, and the reference quality factor value is the threshold value for the wireless power reception. The quality factor value measured at the reference operating frequency with the device turned off. could be.

[0023] In addition, the reference peak frequency is set in the charging area when only the wireless power receiver is placed in the charging area. It may be the frequency having the maximum quality factor value within the operating frequency band.

[0024] In addition, the foreign object detection method may further include a method for detecting a foreign object, the method comprising the steps of: and the quality factor value is determined after detecting the object. The measurements can be taken with the power transmission temporarily interrupted before proceeding to the step of

[0025] In addition, the method of detecting a foreign substance further comprises: The method may further include interrupting power transmission to the power receiver.

[0026] The foreign matter detection method further comprises the step of: detecting a foreign matter after interrupting the power transmission. The step of outputting a predetermined warning alarm indicative of the above may further be included.

[0027] The foreign matter detection method further includes determining whether the detected foreign matter has been removed from the charging area. If the detected foreign matter is removed as a result of the confirmation, Power transmission to the wireless power receiver can be initiated and the warning alarm can be cancelled.

[0028] The foreign substance detection status packet further includes mode information, and based on the mode information, Whether information about the reference peak frequency is included in the foreign substance detection status packet It can be identified.

[0029] The foreign substance detection method further comprises: determining a first maximum quality factor value corresponding to the reference peak frequency; receiving from the wireless power receiver, and determining whether the first maximum quality factor value is greater than the current peak frequency; and calculating a quality factor shift value by subtracting the second maximum quality factor value corresponding to the wave number. and further using said quality factor transfer value to correct said measured quality factor value. can.

[0030] Also, the first maximum quality factor value is received in the foreign substance detection status packet. It is possible.

[0031] Also, the step of determining whether or not the foreign matter exists is performed by determining whether or not the corrected quality factor value is the quality factor. determining that a foreign substance is present if the factor is smaller than a critical value; If the coefficient value is greater than or equal to the quality factor critical value, it is determined that no foreign matter is present. The floor may include.

[0032] According to another embodiment of the present invention, a method for detecting a foreign object in a wireless power transmitter includes: For example, a step of searching for a current peak frequency having a maximum quality factor value within an operating frequency band; measuring an output voltage level at a start frequency of said operating frequency band and said current peak frequency; calculating a quality factor slope based on the measured output voltage level; and determining whether or not a foreign substance is present based on the obtained quality factor slope. .

[0033] Here, the quality factor slope is a function of the output voltage level corresponding to the current peak frequency and the The difference value of the output voltage level corresponding to the start frequency is calculated by dividing the current peak frequency by the start frequency. It can be calculated by dividing by the difference value of

[0034] The step of determining whether or not the foreign matter exists may further include determining whether or not the calculated quality factor slope is a predetermined slope. determining whether the quality factor slope is smaller than a critical value; and if the quality factor slope is smaller than a critical value, determining whether or not a foreign substance is present; and if the determination result is that the foreign substance is greater than or equal to the foreign substance, determining whether or not a foreign substance is present. and determining that the

[0035] According to another embodiment of the present invention, a method for detecting a foreign object in a wireless power transmitter includes: searching for a current peak frequency having a maximum quality factor value within an operating frequency band; and determining a quality factor value at the start frequency of the operating frequency band and the current peak frequency. a step of calculating a quality factor slope based on the determined quality factor value; and determining whether or not a foreign substance is present based on the determined quality factor slope.

[0036] Here, the quality factor slope is a function of the quality factor value corresponding to the current peak frequency and the starting frequency. The difference value of the quality factor value corresponding to the frequency is the difference value between the current peak frequency and the start frequency. It can be calculated by dividing by

[0037] A foreign matter detection device for detecting a foreign matter placed in a charging area according to still another embodiment of the present invention. The device includes a measurement unit that measures a quality factor value corresponding to a reference operating frequency when an object is detected, and a motion A search unit searches for a current peak frequency having a maximum quality factor value within a frequency band, and a reference peak frequency. A foreign object detection status packet including information about the power frequency is received from the wireless power receiver. a communication unit for measuring the frequency of the current peak frequency by using a difference value between the current peak frequency and the reference peak frequency; a correction unit for correcting the determined quality factor value, and a comparison unit for comparing the corrected quality factor value with a predetermined quality factor critical value. and a detection unit for comparing the threshold values ​​to determine whether or not a foreign substance is present.

[0038] Here, the foreign substance detection status packet further includes a reference quality factor value, A threshold value is determined based on the reference quality factor value, and the reference quality factor value is the threshold value for the wireless power reception. The quality factor value measured at the reference operating frequency with the device turned off. could be.

[0039] In addition, the reference peak frequency is set when only the wireless power receiver is placed in the charging area. It may be the frequency having the maximum quality factor value within the operating frequency band.

[0040] The measurement unit temporarily stops power transmission before entering into a process of identifying the wireless power receiver. The quality factor value may be measured in an interrupted state to search for the current peak frequency. .

[0041] If a foreign object is detected as a result of the determination, power is transmitted to the wireless power receiver. can be interrupted.

[0042] In addition, the foreign matter detection device detects that a foreign matter has been detected after the power transmission is interrupted. The device may further include an alarm unit that outputs a predetermined warning alarm indicating the above.

[0043] The foreign matter detection device also determines whether the detected foreign matter has been removed from the charging area. If the detected foreign matter is removed, the control unit The control unit resumes power transmission to the wireless power receiver so that the warning alarm is released. It can be controlled as follows.

[0044] The foreign substance detection status packet further includes mode information, and based on the mode information, Whether information about the reference peak frequency is included in the foreign substance detection status packet It can be identified.

[0045] The correction unit also calculates a first maximum quality factor value corresponding to the reference peak frequency from the first maximum quality factor value. When the wireless power receiver receives the first maximum quality factor value, the current peak a second maximum quality factor value corresponding to the second frequency is subtracted from the second maximum quality factor value to calculate a quality factor shift value; The factor transfer value can further be used to correct the measured quality factor value.

[0046] Here, the first maximum quality factor value is received by being included in the foreign substance detection status packet. It is possible.

[0047] Also, the detection unit detects if the corrected quality factor value is smaller than the quality factor critical value. , it is determined that a foreign substance is present, and the corrected quality factor value is greater than the quality factor critical value. If the results are the same or similar, it can be determined that no foreign substance is present.

[0048] A foreign matter detection device for detecting a foreign matter placed in a charging area according to still another embodiment of the present invention. If the device detects an object, it detects the current peak frequency with the highest quality factor value in the operating frequency band. a peak frequency search unit for searching for a start frequency of the operating frequency band and the current peak frequency; an output voltage measuring unit for measuring an output voltage level at a frequency; a quality factor slope determining unit for calculating a quality factor slope based on the calculated quality factor slope; and a foreign substance detection unit that determines whether or not a foreign substance is present based on the detected foreign substance.

[0049] A foreign matter detection device for detecting a foreign matter placed in a charging area according to still another embodiment of the present invention. If the device detects an object, it detects the current peak frequency with the highest quality factor value in the operating frequency band. a peak frequency search unit for searching for a start frequency of the operating frequency band and the current peak frequency; A quality factor measuring unit for measuring a quality factor value at a wave number, and A quality factor slope determination unit that calculates a quality factor slope and a quality factor slope determination unit that calculates a quality factor slope based on the calculated quality factor slope. and a foreign substance detection unit for determining whether or not a foreign substance is present.

[0050] The present invention also provides a method for detecting foreign substances based on quality factors and a method for detecting foreign substances based on peak frequencies. The detection method is adapted according to whether or not each method detects foreign substances, improving the foreign substance detection capability. It is an object of the present invention to provide a method for detecting foreign substances and an apparatus and system therefor that can improve the quality of the foreign substances. can.

[0051] In addition, the present invention provides a method for detecting a difference in the frequency of a current peak based on the direction of movement of the current peak frequency relative to the reference peak frequency. To provide a method for detecting foreign substances capable of detecting a substance, and an apparatus and system therefor. It is possible.

[0052] A further embodiment of the present invention provides a method for performing any one of the above foreign substance detection methods. It is possible to provide a computer-readable recording medium having the above program recorded thereon.

[0053] The above aspects of the present invention are merely some of the preferred embodiments of the present invention, and the technical features of the present invention may be varied in various ways. Various illustrated embodiments are described in detail below by those skilled in the art. These and other objects, features and advantages of the present invention will become apparent from the following detailed description of the invention. Effect of the Invention

[0054] The effects of the method, device and system according to the present invention are as follows.

[0055] The present invention provides a method for detecting foreign matter for wireless charging, and an apparatus and system therefor. There are advantages.

[0056] The present invention also relates to a method for detecting foreign substances that can detect foreign substances more accurately, and It would be an advantage to provide an apparatus and system for:

[0057] In addition, the present invention can minimize unnecessary power consumption and heat generation caused by foreign matter. There are advantages.

[0058] In addition, the present invention detects foreign matter according to the degree of movement of the current peak frequency relative to the reference peak frequency. By dynamically correcting the quality factor values ​​measured during detection, foreign substances can be detected more accurately. It is an advantage to provide a method and apparatus for detecting foreign matter that can achieve the above-mentioned object.

[0059] The present invention also provides an output power measurement system for the start frequency and the current peak frequency within the operating frequency band. Calculate a quality factor slope based on the pressure level and compare it to a predetermined quality factor slope critical value. By doing so, a foreign substance detection method and an apparatus therefor that can detect foreign substances more accurately are provided. It is an advantage of the present invention to provide a system for

[0060] Another object of the present invention is to provide a method for determining a start frequency and a current peak frequency within an operating frequency band. A quality factor slope is calculated based on the measured quality factor value, and the calculated quality factor slope is compared with a predetermined quality factor slope critical value. A method for detecting foreign substances that can detect foreign substances more accurately by comparing the measured value with the measured value and the method It would be advantageous to provide an apparatus and system for performing

[0061] The present invention also relates to a method for detecting foreign matter based on quality factor and a method for detecting foreign matter based on peak frequency. A foreign substance detection method capable of improving foreign substance detection capability by adaptively applying the method. It would be advantageous to provide a method and an apparatus and system therefor.

[0062] The present invention also provides a method for detecting foreign matter based on the direction of movement of the peak frequency. It would be advantageous to provide a quality detection method and an apparatus and system therefor.

[0063] The effects obtained by the present invention are not limited to those mentioned above, and other effects not mentioned are The following description will clearly explain the present invention to those skilled in the art. Wax. [Brief description of the drawings]

[0064] [Figure 1] 1 is a block diagram illustrating a wireless charging system according to an embodiment of the present invention.

[0065] [Diagram 2] FIG. 11 is a block diagram illustrating a wireless charging system according to another embodiment of the present invention.

[0066] [Diagram 3] 4 is a diagram illustrating a sensing signal transmission process in a wireless charging system according to an embodiment of the present invention.

[0067] [Figure 4] 4 is a state transition diagram illustrating a wireless power transmission process according to an embodiment of the present invention.

[0068] [Figure 5a] 4 is a state transition diagram illustrating a wireless power transmission process according to an embodiment of the present invention.

[0069] [Figure 5b] 4 is a state transition diagram illustrating a wireless power transmission process according to an embodiment of the present invention.

[0070] [Figure 6] 1 is a block diagram illustrating a structure of a wireless power transmitter according to an embodiment of the present invention.

[0071] [Figure 7]7 is a block diagram for explaining the structure of a wireless power receiver that cooperates with the wireless power transmitter of FIG. 6.

[0072] [Figure 8] 2 is a diagram illustrating a method for modulating and demodulating a wireless power signal according to an embodiment of the present invention.

[0073] [Figure 9] FIG. 2 is a diagram illustrating a packet format according to an embodiment of the present invention.

[0074] [Figure 10] FIG. 2 is a diagram for explaining types of packets according to an embodiment of the present invention.

[0075] [Figure 11a] 1 is a diagram illustrating a structure of a foreign substance detection device according to an embodiment of the present invention;

[0076] [Figure 11b] 1 is a diagram illustrating a structure of a foreign substance detection device according to an embodiment of the present invention;

[0077] [Figure 12] FIG. 11 is a block diagram illustrating a structure of a foreign substance detection device according to another embodiment of the present invention.

[0078] [Figure 13a] 4 is a diagram illustrating a state transition process for detecting a foreign substance in the foreign substance detection device according to the embodiment of the present invention. FIG.

[0079] [Figure 13b] 4 is a diagram illustrating a state transition process for detecting a foreign substance in the foreign substance detection device according to the embodiment of the present invention. FIG.

[0080] [Figure 13c] 4 is a diagram illustrating a state transition process for detecting a foreign substance in the foreign substance detection device according to the embodiment of the present invention. FIG.

[0081] [Figure 13d] 4 is a diagram illustrating a state transition process for detecting a foreign substance in the foreign substance detection device according to the embodiment of the present invention. FIG.

[0082] [Figure 14a] A diagram to explain the message structure of an FOD status packet according to one embodiment of the present invention.

[0083] [Figure 14b] A diagram to explain the message structure of an FOD status packet according to one embodiment of the present invention.

[0084] [Figure 15] A diagram for explaining the message structure of an FOD status packet according to another embodiment of the present invention.

[0085] [Figure 16] 4 is a flowchart illustrating a method for detecting a foreign object in a wireless power transmission apparatus according to an embodiment of the present invention.

[0086] [Figure 17] 11 is a table showing experimental results for explaining reference peak frequencies for each receiver type and changes in peak frequencies due to the placement of foreign matter according to an embodiment of the present invention.

[0087] [Figure 18] 11 is a graph showing experimental results illustrating changes in quality factor value and peak frequency due to the placement of a foreign material in a wireless charging system according to the present invention.

[0088] [Figure 19] FIG. 13 is a block diagram illustrating the configuration of a foreign substance detection device according to still another embodiment of the present invention.

[0089] [Figure 20]11 is a diagram illustrating a change in the slope of a quality factor depending on the presence or absence of a foreign substance in a wireless charging system according to the present invention. FIG.

[0090] [Figure 21a] 4 is a flowchart illustrating a method for detecting a foreign object in a wireless power transmission apparatus according to another embodiment of the present invention. [Figure 21b] 4 is a flowchart illustrating a method for detecting a foreign object in a wireless power transmission apparatus according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0091] According to an embodiment of the present invention, a method for detecting a foreign object in a wireless power transmitter includes: measuring a quality factor value corresponding to an operating frequency; and determining whether the quality factor value in the operating frequency band is the maximum. The step of searching for a current peak frequency, which is receiving a foreign substance detection status packet from a wireless power receiver; correcting the measured quality factor value using a difference value between the reference peak frequencies; The corrected quality factor value is compared with a predetermined quality factor critical value to determine whether or not a foreign substance is present. and MODE FOR CARRYING OUT THEINVENTION

[0092] Hereinafter, the apparatus and various methods to which the embodiments of the present invention are applied will be described in detail with reference to the drawings. The suffixes "module" and "part" for components used in the following description are for clarity. These are given or mixed for the sole consideration of ease of drafting, and are distinguished from one another as such. It does not have any specific meaning or role.

[0093] In the description of the embodiment, when it is described as being formed "on or under" each component, In this case, the upper or lower means that the two components are in direct contact with each other or that one or more further components are in contact with each other. This includes all of the components that are disposed between two components. In this case, it can mean not only above but also below one component.

[0094] In the description of the embodiment, a device equipped with a function of transmitting wireless power in a wireless charging system For convenience of explanation, the device will be referred to as a wireless power transmitter, a wireless power transmission device, or a wireless power transmission device. , wireless power transmitter, transmitting end, transmitter, transmitting device, transmitting side, wireless power transmission device, wireless power In addition, the wireless power receiving device will receive wireless power from the wireless power transmitting device. For the sake of convenience, the following expressions are used to refer to a device equipped with the functions of wireless power receiving device, Wireless power receiver, wireless power receiving device, wireless power receiver, receiving terminal, receiving side, receiving device It can be used in combination with other devices, such as transmitters, receivers, etc.

[0095] The transmitter according to the present invention may be in the form of a pad, a stationary type, or an AP (Access Point). It can be configured in various forms, including small base station form, stand form, ceiling embedded form, and wall mounted form. One transmitter can transmit power to multiple wireless power receiving devices. To this end, the transmitter may also comprise at least one means for wireless power transmission, where: The wireless power transmission means generates a magnetic field in a power transmitting end coil, and receives the magnetic field. Based on the electromagnetic induction method, which uses the principle of electromagnetic induction to charge the battery, electricity is induced in the input coil. Various wireless power transmission standards can be used. Here, the wireless power transmission means is The wireless charging technology standard organization WPC (Wireless Power Consortium) m) and Electromagnetics as defined by the Power Matters Alliance (PMA) This may include inductive wireless charging technology.

[0096] Also, a receiver according to an embodiment of the present invention includes at least one wireless power receiving means. It is also possible to receive radio power from two or more transmitters simultaneously. The line power receiving means is the WPC (Wireless Power Charging Standards Committee) Consortium and PMA (Power Matters Alliance) ) can include electromagnetic induction wireless charging technology as defined in

[0097] The receiver according to the present invention can be used in a mobile phone, a smartphone, smart phone, laptop computer , digital broadcasting terminals, PDAs (Personal Digital Assistants) nts), PMP (Portable Multimedia Player), navigation game applications, MP3 players, electric toothbrushes, electronic tags, lighting devices, remote controls Used for small electronic devices such as sensors, floats, and wearable devices like smart watches. However, the present invention is not limited to this, and the wireless power receiving means according to the present invention may be installed. Any device that can charge a battery will suffice.

[0098] FIG. 1 is a block diagram illustrating a wireless charging system according to an embodiment of the present invention.

[0099] Referring to FIG. 1, a wireless charging system mainly includes a wireless power transmitting terminal that transmits power wirelessly. 10, a wireless power receiving terminal 20 for receiving the transmitted power, and The electronic device 30 may include:

[0100] As an example, the wireless power transmitting end 10 and the wireless power receiving end 20 are used for wireless power transmission. In-band communication is used to exchange information using the same frequency band as the This can be done.

[0101] In the in-band communication, the power signal 41 sent by the wireless power transmitting end 10 is When the wireless power receiving end 20 receives the power signal, the wireless power receiving end 20 modulates the received power signal and The generated signal 42 can be transmitted to the wireless power transmitting end 10.

[0102] As another example, the wireless power transmitting end 10 and the wireless power receiving end 20 may be used as a dynamic power transmitting end. Out-of-band (OOB) is a type of communication that exchanges information using a separate frequency band different from the operating frequency. d) Communication is also possible.

[0103] For example, information exchanged between the wireless power transmitting end 10 and the wireless power receiving end 20 may be In addition to status information, control information may also be included. The state information and control information will become more apparent from the description of the embodiments below.

[0104] The in-band and out-of-band communications may provide bidirectional communication, but are not limited thereto. However, in other embodiments, unidirectional or half-duplex communication may be provided. do.

[0105] For example, in unidirectional communication, the wireless power receiving end 20 transmits information only to the wireless power transmitting end 10. However, the present invention is not limited to this. It may also transmit information to a

[0106] The half-duplex communication method allows bidirectional communication between the wireless power receiving end 20 and the wireless power transmitting end 10. However, it has the characteristic that information can be transmitted by only one device at any one time.

[0107] According to an embodiment of the present invention, the wireless power receiving end 20 acquires various status information of the electronic device 30. As an example, the status information of the electronic device 30 may include current power usage information, execution information, and the like. Information to identify the application in use, CPU usage information, battery charge status information, battery -output voltage / current information, etc. from electronic device 30 Any information that can be obtained and that can be used for wireless power control is sufficient.

[0108] In particular, the wireless power transmitter 10 according to an embodiment of the present invention may include a predetermined The wireless power receiving end 20 can transmit the packet to the wireless power receiving end 20. If it is confirmed that the wireless power transmitter 10 supports the fast charging mode, The electronic device 30 can inform the user of this. The electronic device 30 has a predetermined display means, A display means, which may be a liquid crystal display, indicates that fast charging is possible. It is possible.

[0109] Also, the user of the electronic device 30 selects a predetermined high-speed charging request button displayed on the liquid crystal display means. Alternatively, the wireless power transmitter 10 may be controlled to operate in a fast charging mode. In this case, when the user selects the fast charging request button, the electronic device 30 The wireless power receiving terminal 20 may transmit a high-speed charging request signal to the wireless power receiving terminal 20. The wireless power transmitter 1 generates a charging mode packet corresponding to the received fast charging request signal. 0, the general low-power charging mode can be converted to the fast charging mode. Cut.

[0110] FIG. 2 is a block diagram illustrating a wireless charging system according to another embodiment of the present invention. .

[0111] For example, as shown by reference numeral 200a, the wireless power receiving end 20 may include a plurality of wireless power A single wireless power transmitting end 10 may be connected to a plurality of wireless power receiving devices. Here, the wireless power transmitting end 10 can be connected to multiple However, the present invention is not limited to this. For example, the wireless power transmitting end 10 may transmit different frequencies assigned to the wireless power receiving devices. The band can be used to distribute and transmit power to multiple wireless power receiving devices.

[0112] Here, the number of wireless power receiving devices that can be connected to one wireless power transmitting device 10 is Power requirement by receiving device, battery charge status, power consumption of electronic devices and wireless power transmission device The power consumption can be adaptively determined based on at least one of the available power amount of the device.

[0113] As another example, as shown by reference numeral 200b, the wireless power transmitting end 10 may include a plurality of wireless power In this case, the wireless power receiving end 20 may be composed of a plurality of wireless power transmitting devices. and can simultaneously connect to the wireless power transmitting device and simultaneously receive power from the connected wireless power transmitting device. Here, the wireless power receiving terminal 20 can receive the wireless power and perform charging. The number of transmitting devices is determined based on the power requirement of the wireless power receiving end 20, the battery charge state, and the power of the electronic device. It can be adaptively determined based on the amount of power consumed, the amount of available power of the wireless power transmission device, etc. .

[0114] In addition, multiple wireless power transmitting devices may transmit power to multiple wireless power receiving devices. Here, one wireless power transmitting device transmits power to one wireless power receiving device. .

[0115] FIG. 3 illustrates a sensing signal transmission process in a wireless charging system according to an embodiment of the present invention. This is a diagram for

[0116] As an example, the wireless power transmitter is equipped with three transmitting coils 111, 112, and 113. Each transmitting coil can overlap with other transmitting coils in some areas. In this case, the wireless power transmitters sense the presence of the wireless power receivers via their respective transmission coils. For this purpose, predetermined sensing signals 117, 127, e.g. digital ping signals, are sequentially arranged in a predefined order. Next send.

[0117] As shown in FIG. 3, the wireless power transmitter includes a first sensing signal transmission path indicated by reference numeral 110. The wireless power receiver 115 sequentially transmits the sensing signal 117 according to the process, and outputs a signal strength indicator (S Transmitting coil 1 where the signal strength indicator (SI) 116 was received 11, 112. Next, the wireless power transmitter is shown in FIG. The second sensing signal transmission process sequentially transmits the sensing signal 127 and the signal strength indicator 126. The power transmission efficiency (or charging efficiency) of the transmitting coils 111 and 112 from which the Identifying a transmitting coil having a good alignment between the transmitting coil and the receiving coil, It is possible to control the power to be sent via the Cut.

[0118] As shown in FIG. 3, the reason why the wireless power transmitter performs two sensing signal transmission processes is that To more accurately identify whether the receiving coil of the wireless power receiver is well aligned with the coil It is.

[0119] As shown in FIG. 3 with reference numbers 110 and 120, a first transmitting coil 111 and a second transmitting coil 120 are provided. If the signal strength indicator 116, 126 is received at the transmitting coil 112, the wireless power transmitter are the signal strength indicators received by the first transmitting coil 111 and the second transmitting coil 112, respectively. Select the best aligned transmit coil based on the indicator 126, and set the selected transmit coil to Use it to wirelessly charge

[0120] FIG. 4 is a state transition diagram illustrating a wireless power transmission process according to an embodiment of the present invention.

[0121] Referring to FIG. 2, power transmission from a transmitter to a receiver is roughly divided into a selection stage. Action Phase 410, Ping Phase 420, Identification and Identification and Configuration Phase hase 430 and Power Transfer Phase 26 It can be classified as 0.

[0122] A selection step 410 is performed to determine whether a particular error or may be a transition step when a specific event is detected. Certain events will become clear from the following description.

[0123] Also, in a selection step 410, the transmitter monitors whether an object is present on the charging interface surface. If an object is placed on the surface of the charging interface of the transmitter, If it is detected, it can transition to a ping step 420 (S401).

[0124] In selection step 410, the transmitter sends out a very short pulse of analog ping (Analog Ping ng) signal, and the charging interface can be changed based on the current change of the transmitting coil. There is an object in the active area of ​​the surface of the device, i.e. the area that can be charged. It is possible to sense

[0125] In the ping step 420, if the transmitter detects an object, it activates the receiver, i.e., and a digital booting for identifying whether the object is a receiver. In the ping step 420, the transmitter transmits a digital ping. A response signal to the tapping, e.g. a signal strength indicator, can be received from the receiver. If the ping step is not completed, the process may proceed to the selection step 410 again (S402). At step 420, the transmitter receives a signal from the receiver indicating that the power transfer is complete, i.e. If the charging completion signal is received, the process may proceed to a selection step 410 (S403).

[0126] Once the ping step 420 is completed, the transmitter identifies the receiver and transmits the receiver's configuration and status information. The process may proceed to an identification and configuration step 430 for collecting (S404).

[0127] In the identification and configuration step 430, the sender determines whether an unwanted packet is received (unexpected packet). received packet), when a desired packet is not received for a predefined period of time. time out, or a packet transmission error If no power transfer contract is set, Then, the process proceeds to selection step 410 (S405).

[0128] When the identification and configuration of the receiver is completed, the transmitter transmits wireless power. Then, the process can proceed to 440 (S406).

[0129] In the power transmission step 440, the transmitter determines whether an unwanted packet is received (unexpected packet). ted packet), or if the desired packet is not received for a predefined period of time ( time out), whether a violation of the existing power transmission contract occurs (power transfer contract violation), when charging is complete, Then, the process can proceed to selection step 410 (S407).

[0130] In addition, in the power transmission step 440, the transmitter changes the power transmission contract depending on the state change of the transmitter. If the profile needs to be reconstructed, a transition can be made to the identification and construction stage 430 (S4 08).

[0131] The power transfer agreement described above is set based on the status and characteristic information of the transmitter and receiver. As an example, the status information for a transmitter can include information about the maximum amount of power that can be transmitted, The receiver status information may include information about the number of receivers that can be accommodated, and the required power. It may include information about.

[0132] 5a and 5b are state transition diagrams illustrating a wireless power transmission process.

[0133] Referring to FIG. 5a, the power transfer from a transmitter to a receiver according to one embodiment of the present invention is In addition, the Selection Phase 510 and the Ping Phase 520, Identification and Configuration Phase figuration Phase) 530, Negotiation Phase ase) 540, Calibration Phase) 550, Power Transmission Stage Power Transfer Phase 560 and Renegotiation Phase The retrieval phase can be divided into 570 phases.

[0134] A selection step 510 is performed to determine whether a particular error or is a step in which a transition occurs when a specific event is detected, for example, S502, S504, S 508, S510 and S512, where the specific error and the specific event are As will become apparent from the following description, in the selection step 510, the transmitter It can monitor whether an object is present on the interface surface. If it detects that an object has been placed on the interface surface, it transitions to a ping step 520. In a selection step 510, the transmitter sends out a very short pulse of analog ping (Ana log Ping signal and transmit the signal to the transmitter coil or primary coil. l) Active area on the interface surface based on the change in current It can sense the presence of an object.

[0135] If an object is detected in the selection step 510, the wireless power transmitter is connected to a wireless power resonant circuit (e.g. , the power transfer coil and / or the resonant capacitor) can be measured.

[0136] In one embodiment of the present invention, if an object is detected in the selection step 510, a foreign object is detected in the charging area. The quality factor can be measured to determine whether a wireless power receiver is placed in the same place. The coil provided in the line power transmitter changes in inductance and / or coil current due to environmental changes. The series resistance in the MOSFET can be reduced, which results in a reduced quality factor value. The wireless power transmitter uses the measured quality factor value to determine whether or not a foreign substance is present. The reference quality factor value measured in advance when no foreign object is placed in the power receiving area is received wirelessly. In a negotiation step 540, the received reference quality factor value and the measured The presence or absence of foreign matter can be determined by comparing the quality factor values ​​obtained by the standard. For low-value wireless power receivers, examples include the type, use and characteristics of the wireless power receiver For a particular wireless power receiver having a low reference quality factor value due to the presence of foreign matter, There is no significant difference between the quality factor value measured in the case and the standard quality factor value, so it is difficult to determine whether or not foreign matter is present. Problems that are difficult to judge may occur. Therefore, it is necessary to consider other factors more or Other methods must be used to determine whether or not foreign matter is present.

[0137] In yet another embodiment of the present invention, if an object is detected in the selection step 510, a different object is detected in the charging area. In order to determine whether a wireless power receiver is placed with the material, For example, the quality factor value of the operating frequency domain can be measured. The change in the temperature can reduce the inductance and / or the series resistance in the coil. , which allows the resonant frequency of the coil of the wireless power transmitter to be changed (shifted). That is, the quality factor peak is the frequency at which the maximum quality factor value in the operating frequency band is measured. The peak frequency can shift.

[0138] As an example, a wireless power receiver includes a magnetic shield with high magnetic permeability. Therefore, high permeability increases the inductance value measured in the coil of a wireless power transmitter. On the other hand, foreign metal materials can reduce the inductance value.

[0139] For example, when the resonant frequency of the coil of the wireless power transmitter is 100 kHz, To account for the change in the measured quality factor value when a transmitter or foreign object is placed in the charging area The graph for this is shown in Figure 5b.

[0140] Referring to FIG. 5b, in general, for an LC resonant circuit, the resonant frequency (f_resonant t) is Calculated by TIFF0007678843000001.tif7169.

[0141] Referring to the left graph of FIG. 5b, if only the wireless power receiver is placed in the charging area, L As the value increases, the resonant frequency decreases and shifts to the left on the frequency axis. become.

[0142] On the other hand, referring to the right graph of Figure 5b, if a foreign object is placed in the charging area, the L value decreases. This reduces the resonance frequency, so it shifts to the right on the frequency axis. become.

[0143] The frequency with the highest measured quality factor, i.e. the measured peak frequency, is used to identify the foreign matter. To determine the presence of foreign matter, the wireless power transmitter must be in a state where no foreign matter is placed in the charging area. The reference maximum quality factor frequency, i.e., the reference peak frequency value, is measured in advance in the wireless power receiving state. In a negotiation step 540, the received reference peak frequency value and the measurement The determined peak frequency values ​​can be compared to determine whether or not a foreign substance is present.

[0144] The method of detecting foreign matter by comparing peak frequencies is used in conjunction with the method of comparing quality factor values. If the comparison of the reference quality factor value and the measured quality factor value shows no significant difference, If the difference is less than 10%, compare the reference peak frequency with the measured peak frequency. On the other hand, if the difference in quality factor value exceeds 10%, Therefore, the wireless power transmitter can immediately determine that a foreign object is present.

[0145] In yet another embodiment, a comparison of the reference quality factor value with the measured quality factor value indicates that no foreign matter is present. If it is determined that there is no foreign substance, the reference peak frequency is compared with the measured peak frequency to determine the presence of the foreign substance. If it is difficult to detect foreign matter using quality factors, the wireless power The receiver includes information about the reference peak frequency in the foreign object detection status packet and controls the wireless power supply. The wireless power transmitter uses the information about the reference peak frequency to detect the foreign object. By detecting the quality, the ability to detect foreign substances can be improved.

[0146] The detailed method for comparing the benchmark quality factors is described in the Examples below.

[0147] In the ping step 520, if the transmitter detects an object, it wakes up the receiver. ) to identify whether the detected object is a wireless power receiver or not, and In a ping step 520, the transmitter transmits a digital ping. If no response signal, such as a signal strength packet, is received from the receiver, , and may transition back to selection step 510. Also, in ping step 520, the transmitter may Receive a signal indicating that power transfer is complete from the receiver, i.e. a charging completion packet If so, a transition to selection step 510 may be made.

[0148] Once the ping step 5220 is completed, the transmitter identifies the receiver and transmits the receiver configuration and status information. The process may proceed to an identification and configuration step 530 for collecting the

[0149] In the identification and configuration step 530, the transmitter determines whether an unwanted packet is received (unexpected packet). received packet), when a desired packet is not received for a predefined period of time. time out, or a packet transmission error If no power transfer contract is set, A transition to contract selection step 510 may then be made.

[0150] The transmitter identifies the received configuration packet (Configura Negotiation Field value of the Response packet Based on this, it can be determined whether or not entering the negotiation stage 540 is necessary.

[0151] If negotiation is necessary, the transmitter proceeds to a negotiation step 540 to determine whether a given FOD detection is necessary. The process can be carried out.

[0152] On the other hand, if the confirmation result indicates that negotiation is not necessary, the transmitter immediately proceeds to the power transmission step 560. It is also possible.

[0153] In the negotiation step 540, the transmitter negotiates with the Foreign Observer (FOD) that includes the reference quality factor value. Inject Detection) status packet can be received. A FOD status packet may be received that includes a peak frequency value. A status packet may be received that includes a quality factor value and a reference peak frequency value. Then, the transmitter determines a quality factor threshold value for FO detection based on the reference quality factor value. The transmitter can determine the peak frequency for FO detection based on the reference peak frequency value. A critical value can be determined.

[0154] The transmitter determines the quality factor threshold for FO detection and the currently measured quality factor value ( Detect the presence of FO in the charging area using the quality factor value measured before the ping stage It is possible to control the power transmission according to the FO detection result. If a power failure is detected, power transmission may be interrupted, but is not limited to this.

[0155] The transmitter determines the peak frequency threshold for FO detection and the currently measured peak The frequency value (peak frequency value measured before the ping phase) is used to detect the presence of FO in the charging area. It is possible to detect whether the power is being transmitted or not, and the power transmission can be controlled according to the result of the FO detection. As an example, but not limited to, if FO is detected, power transmission may be interrupted. I can't.

[0156] If FO is detected, the transmitter can return to selection step 510. If not detected, the transmitter proceeds through a correction stage 550 to a power transfer stage 560. In detail, if no FO is detected, the transmitter may correct the received signal in the correction step 550. determining the strength of the power received at the end and determining the strength of the power transmitted from the transmitting end; The power loss at the receiving end and the transmitting end can be measured. That is, the transmitter performs a correction step 55 0, predicting power loss based on the difference between the transmission power at the transmitting end and the reception power at the receiving end. In one embodiment, the transmitter can provide a clinical signal for FOD detection that reflects the predicted power loss. The threshold value can also be corrected.

[0157] In the power transmission step 560, the transmitter checks whether an unexpected packet is received. ed packet), or if a desired packet is not received for a predefined period of time (t ime out), or will there be a violation of the power transfer agreement already established (power transfer agreement)? r transfer contract violation) If charging is completed, A transition can be made to a selection step 510 .

[0158] In addition, in the power transmission step 560, the transmitter changes the power transmission contract depending on the state change of the transmitter. If the contract needs to be restructured, a transition to a renegotiation phase 570 may occur. If the renegotiation is successfully completed, the transmitter may revert to the power transfer stage 560 .

[0159] The power transfer agreement described above is set based on the status and characteristic information of the transmitter and receiver. As an example, the status information for a transmitter can include information about the maximum amount of power that can be transmitted, The receiver status information may include information about the number of receivers that can be accommodated, and the like. It may include information about power, etc.

[0160] FIG. 6 is a block diagram illustrating the structure of a wireless power transmitter according to an embodiment of the present invention. do.

[0161] Referring to FIG. 6, the wireless power transmitter 600 is roughly divided into a power conversion unit 610 and a power transmission unit 612. 620, a communication unit 630, a control unit 640, and a sensing unit 650. The above-mentioned configuration of the wireless power transmitter 600 is not necessarily essential, and more or less may be used. It should be noted that it may also comprise fewer components.

[0162] As shown in FIG. 6, when DC power is supplied from a power supply unit 660, the power conversion unit 610 , and converts it into AC power of a predetermined strength.

[0163] For this purpose, the power conversion unit 610 includes a DC / DC conversion unit 611, an inverter 612, and The frequency generator 613 may include an inverter 612. The inverter may be, but is not limited to, a ridge inverter or a full-bridge inverter. If the circuit configuration can convert DC power into AC power having a specific operating frequency, That's enough.

[0164] The DC / DC converter 611 controls the DC power controller 640 supplied with the DC power from the power supply 650. It can perform the function of converting a signal into DC power of a specific strength.

[0165] Here, the sensing unit 650 measures the voltage / current of the DC converted power and controls it. The sensing unit 650 may provide a signal to the temperature sensor 640 to determine whether overheating has occurred. In order to measure the internal temperature of the wireless power transmitter 600, the internal temperature of the wireless power transmitter 600 is measured, and the measurement result is provided to the control unit 640. For example, the control unit 640 may / The power supply from the power supply unit 650 is adaptively cut off or the amplifier (inverter) is To this end, the power supply to the power converter 612 can be cut off. One side of the power supply unit 610 is connected to a power supply unit 650, and the other side is connected to an amplifier 612. The power supply device may further include a predetermined power cutoff circuit for cutting off the power supplied thereto.

[0166] The inverter 612 converts the DC / DC converted DC power into The generated reference AC signal can be converted into AC power according to the reference AC signal. The frequency of the signal, i.e., the operating frequency, is dynamically changed in response to a control signal from the control unit 640. The wireless power transmitter 600 according to an embodiment of the present invention adjusts the operating frequency and transmits. The power intensity can also be adjusted.

[0167] For example, the control unit 640 may receive power reception status information of the wireless power receiver via the communication unit 630. and (and) a power control signal, and the received power reception status information or and) determining an operating frequency in response to a power control signal, so that the determined operating frequency is generated. Thus, the frequency generator 613 can be dynamically controlled.

[0168] For example, the power reception status information may include the strength of the output voltage of the rectifier, the power applied to the receiving coil, The power control signal may include, but is not limited to, information on the strength of the current passing through the power supply. These may include a signal to request an increase in power, a signal to request a decrease in power, and the like.

[0169] The power transmission section 620 includes a multiplexer (or multiflexor) 621 and a transmission coil section 622. Here, the transmission coil section 622 is composed of first to n-th transmission coils. Also, the power transmission unit 620 can be configured to receive a specific carrier frequency for power transmission. The system may further include a carrier generator (not shown) for generating a number. The transmission wave generator receives the output AC power of the inverter 612 transmitted through the multiplexer 621 and A specific carrier frequency can be generated for mixing.

[0170] In one embodiment of the present invention, the frequencies of the AC power transmitted to each of the transmitting coils are different from each other. Another embodiment of the present invention uses LC resonance characteristics. Each transmit coil is adjusted differently using a specific frequency controller. The resonant frequencies of the respective transmitting coils may be set differently.

[0171] The multiplexer 621 transmits AC power to the transmission coil selected by the control unit 640. The control unit 640 can perform a switch function for receiving the received signal for each transmitting coil. and selecting a transmitting coil to be used for transmitting power to the corresponding wireless power receiver based on the signal strength indicator. It is possible.

[0172] According to an embodiment of the present invention, the control unit 640 may be configured to transmit and receive power when multiple wireless power receivers are connected. Power can also be transmitted by time division multiplexing for each receiving coil.

[0173] For example, the wireless power transmitter 600 includes three wireless power receivers, i.e., first to third wireless power receivers. The receiver is identified by three different transmitting coils, namely the first to third transmitting coils. When the signal is determined to be a specific time slot, the control unit 640 controls the multiplexer 621 to Therefore, it is possible to control so that AC power is sent only through a specific transmission coil.

[0174] Here, the length of the time slot assigned to each transmitting coil determines the length of the corresponding wireless power receiving coil. However, this is only one example and other examples may be used. The output current of the DC / DC converter 611 is calculated during the time slots assigned to the respective transmitting coils. It is also possible to control the strength of the current power to control the power transmitted from each wireless power receiver.

[0175] The control unit 640 transmits the sensing signal via the first to nth transmission coils 622 during the primary sensing signal transmission process. The control unit 621 can control the multiplexer 621 so that the notification signals can be sent out in sequence. The time when the sensing signal is transmitted can be identified by a timer 655 in the 640. When the transmission time arrives, the multiplexer 621 is controlled to transmit the sensing signal through the corresponding transmission coil. As an example, the timer 655 can be controlled to transmit a ping signal. During the step, a specific event signal can be sent to the control unit 640 at a predetermined period. The control unit 640 controls the multiplexer 621 to output the corresponding event signal every time the corresponding event signal is detected. A digital ping can be controlled to be sent through the transmitting coil.

[0176] In addition, the control unit 640 determines which transmission coil is output from the demodulation unit 632 during the primary sensing signal transmission process. A Signal Strength Indicator is received via A predetermined transmitting coil identifier for identifying whether a signal has been received or not and a signal received through the corresponding transmitting coil The received signal strength indicator may be received.

[0177] For example, in the process of transmitting the second sensing signal, the control unit 640 may The sensed signal can be sent only through the transmitting coil (etc.) from which the signal strength indicator is received. It is also possible to control the multiplexer 621 .

[0178] As another example, the controller 640 may receive a signal strength indicator during the process of transmitting the first sensing signal. If there are multiple transmit coils, the transmit coil from which the signal strength indicator having the maximum value was received is selected. is determined as the transmission coil that should transmit the sensing signal first in the secondary sensing signal transmission process, and the determination result It is also possible to control the multiplexer 621 by

[0179] The communication unit 630 may include at least one of a modulation unit 631 and a demodulation unit 632. do.

[0180] The modulation unit 631 modulates the control signal generated by the control unit 640 and outputs it to the multiplexer 621. Here, the modulation method for modulating the control signal is FSK (Frequency Shift Keying). quency shift keying modulation method, Manchester coding (M Anchester Coding modulation method, PSK (Phase Shift Key ying modulation method, Pulse Width Modulation This includes the differential bi-phase modulation method, etc. It can be, but is not limited to, this.

[0181] If a signal received through the transmission coil is detected, the demodulator 632 demodulates the detected signal. The demodulated signal can be transmitted to the control unit 640. Error Correction (EC) for power control during wireless power transmission EOC (End Of Charge) indicator, Overcharge indicator The wireless power indicators may include, but are not limited to, overvoltage / overcurrent / overheat indicators. Various status information may be included to identify the state of the receiver.

[0182] In addition, the demodulation unit 632 determines from which transmission coil the demodulated signal was received. The control unit can identify the transmitting coil and can provide a predetermined transmitting coil identifier corresponding to the identified transmitting coil. It can also be provided to 640.

[0183] Also, the demodulation unit 632 demodulates the signal received via the transmission coil 622 and outputs the demodulated signal to the control unit 6 40. As an example, the demodulated signal may include a signal strength indicator. However, the demodulated signal may include various status information of the wireless power receiver. This can be done.

[0184] As an example, the wireless power transmitter 600 may transmit wireless power at the same frequency as that used for wireless power transmission. The signal strength indicator is transmitted via in-band communication with a line power receiver. It can be acquired.

[0185] In addition, the wireless power transmitter 600 transmits wireless power using the transmission coil unit 622. In addition, various control signals and As another example, the first to nth transmitting coils of the transmitting coil section 622 can be exchanged. The wireless power transmitter 600 may further include separate coils corresponding to the coils. It is also possible to perform in-band communication with a wireless power receiver using a separate coil provided. You must be careful about this.

[0186] In the above description of FIG. 6, the wireless power transmitter 600 and the wireless power receiver perform in-band communication. However, this is merely an example and may be used for a frequency band used in wireless power signal transmission. It is possible to perform short-distance two-way communication via a frequency band different from the frequency band. For example, Short-distance two-way communication is achieved using low-power Bluetooth communication, RFID communication, UWB communication, and ZigBee. It can be any one of the communications.

[0187] In addition, in the above description of FIG. 6, the power transmission unit 620 of the wireless power transmitter 600 is a multiplexer 62 Although the present invention includes one or more transmit coils 622, this is merely one embodiment, and other embodiments of the transmit coils may be used. It should be noted that the force transmission section 620 may also consist of a single transmitting coil. Must be.

[0188] FIG. 7 is a block diagram for explaining the structure of a wireless power receiver in cooperation with the wireless power transmitter shown in FIG. FIG.

[0189] Referring to FIG. 3, the wireless power receiver 700 includes a receiving coil 710, a rectifier 720, a direct current / DC / DC Converter 730, Load 740, Sensing Unit 7 50, a communication unit 760 and a main control unit 770. 0 may include at least one of a demodulation unit 761 and a modulation unit 762.

[0190] The wireless power receiver 700 shown in the example of FIG. 7 transmits a wireless power transmitter via in-band communication. 600, this is only one example. According to another embodiment of the present invention, the communication unit 760 is a frequency band used for wireless power signal transmission. It may also provide short-range two-way communication over a different frequency band.

[0191] The AC power received via the receiving coil 710 can be transmitted to the rectifier unit 720. The rectifier 720 converts the AC power into DC power and transmits it to the DC / DC converter 730. The DC / DC converter 730 adjusts the strength of the rectifier output DC power according to the load 740. After being converted to a particular required intensity, it can be transmitted to the load 740 .

[0192] The sensing unit 750 measures the DC power intensity output from the rectifier 720 and transmits this to the main control unit 77. 0. Also, the sensing unit 750 may provide a receiving control signal by wireless power reception. 7. Measure the intensity of the current applied to the coil 710 and transmit the measurement result to the main control unit 770. The sensing unit 750 can also measure the internal temperature of the wireless power receiver 700. The determined temperature value may also be provided to the main controller 770.

[0193] As an example, the main controller 770 may compare the measured rectifier output DC power intensity with a predetermined reference value. By comparing the voltages, it is possible to determine whether an overvoltage has occurred. A predetermined packet notifying that a voltage has been generated is generated and transmitted to the modulation unit 762. Here, the signal modulated by the modulation unit 762 is input to the receiving coil 710 or a separate The power may be transmitted to the wireless power transmitter 600 via a signal (not shown).

[0194] In addition, the main control unit 770 detects the rectifier output DC power intensity as a threshold value or higher. When a sensing signal is received, the corresponding signal is The intensity indicator may be transmitted to the wireless power transmitter 600 via the modulation unit 762. As another example, the demodulation unit 761 can be controlled by the receiving coil 710 and the rectifier 72. 0 or the output DC power signal of the rectifier 720 is demodulated to determine whether a sensing signal is received. After the identification, the identification result can be provided to the main controller 770. 70, a signal strength indicator corresponding to the sensing signal can be transmitted through a modulation unit 762. It is possible to control the

[0195] FIG. 8 is a diagram illustrating a method for modulating and demodulating a wireless power signal according to an embodiment of the present invention. be.

[0196] As shown by reference number 810 in FIG. 8, the wireless power transmitting end 10 and the wireless power receiving end 20 are The packet to be transmitted is encoded or decoded based on an internal clock signal having the same period. Can be coded.

[0197] The method of encoding a packet to be transmitted will be described in detail below with reference to FIGS. 1 to 8. .

[0198] Referring to FIG. 1, a wireless power transmitting end 10 or a wireless power receiving end 20 transmits a specific packet. If the wireless power signal is not transmitted, it will have a specific frequency as shown in FIG. 1, reference number 41. The input signal may be an unmodulated AC signal.

[0199] Meanwhile, when the wireless power transmitting end 10 or the wireless power receiving end 20 transmits a specific packet, The wireless power signal is an alternating current modulated with a specific modulation scheme, as shown in FIG. 1, reference numeral 42. As an example, the modulation method may be an amplitude modulation method, a frequency modulation method, a frequency and This may include, but is not limited to, amplitude modulation, phase modulation, and the like.

[0200] Binary data of the packet generated by the wireless power transmitting end 10 or the wireless power receiving end 20 As shown in drawing number 820, the differential double-phase encoding In detail, differential bi-phase encoding can be applied. The input requires two transitions to encode the data bit 1. s) and have one state transition to encode a data bit 0. That is, data bit 1 is clocked on the rising edge of the clock signal. HI state at rising edge and falling edge The data bit 0 is encoded to cause a transition between the LO states. The encoder is designed so that the transition between the HI and LO states occurs on the rising edge of the clock signal. It may be coded.

[0201] The encoded binary data is encoded in byte encoding as shown in drawing number 830. Referring to FIG. 830, a byte-based method according to one embodiment can be applied. The encoding technique applies the corresponding 8-bit encoded binary bitstream. Start bit to identify the beginning and end of this bitstream ) and stop bit, corresponding bit stream (byte) error This is a method of inserting a parity bit to detect whether or not a It is possible.

[0202] FIG. 9 is a diagram for explaining a packet format according to one embodiment of the present invention.

[0203] Referring to FIG. 9, a wireless power transmitter 10 and a wireless power receiver 20 are used for information exchange. The packet format 900 is used for obtaining synchronization for demodulating the corresponding packet and Preamble 910 field to identify the exact start bit of Header to identify the type of message included in the packet ) 920 field, which transmits the contents (or payload) of the corresponding packet The Message 930 field and the corresponding packet have an error. Includes a checksum 940 field to verify that the It can be done.

[0204] The packet receiving end receives the message 920 included in the packet based on the header 920 value. It can also distinguish between 30 sizes.

[0205] In addition, the header 920 can be defined for each step of the wireless power transmission process. The header 920 value is defined to have the same value at different stages of the wireless power transmission process. For example, referring to FIG. 10, the power transmission end (End Power Transfer) and the header value corresponding to the end of power transfer in the power transfer phase Note that both are 0x02 and are identical.

[0206] The message 930 includes data to be transmitted from the transmitting end of the corresponding packet. The data contained in the message 930 field is the report to the other party. rt), a request or a response, This is not limited to the above.

[0207] According to another embodiment of the present invention, a packet 900 includes a packet ID identifying a transmitting end that transmits the corresponding packet. receiving end identification information for identifying a receiving end that receives the corresponding packet; Here, the transmitting end identification information and the receiving end identification information may be included. The identification information may include IP address information, MAC address information, product identification information, etc. However, the present invention is not limited to the above. It is sufficient if the information is sufficient.

[0208] According to yet another embodiment of the present invention, a packet 900 is sent by multiple devices. If the relevant receiving group needs to receive the It may also include other information.

[0209] FIG. 10 illustrates a wireless power receiver according to an embodiment of the present invention. FIG. 2 is a diagram for explaining types of packets.

[0210] Referring to FIG. 10, a packet transmitted from a wireless power receiver to a wireless power transmitter includes a sensing Signal Strength (SSI) is used to transmit the strength information of the received ping signal. h) Packet, power transmission type (End) for requesting the transmitter to stop power transmission After receiving a control error packet for control, Power Control Hold (PCH) for transmitting time information to wait before adjusting power Control Hold-off packet, configuration packet for transmitting receiver configuration information Identification packet and extended identification packet for transmitting receiver identification information, general request message A general request packet for transmitting a special request message, and a special request packet for transmitting a special request message. a request packet, an FOD status packet for transmitting a reference quality factor value for FOD detection; A control error packet for controlling the transmitter's transmission power, and a renegotiation packet for starting renegotiation 24-bit received power packet and 8-bit received power packet for transmitting received power strength information A power packet for transmitting a current load and a charging status packet for transmitting charging status information of the current load are included. It is possible.

[0211] The packet transmitted from the wireless power receiver to the wireless power transmitter is used for wireless power transmission. The signal may be transmitted using in-band communication using the same frequency band as that used by the signal.

[0212] FIG. 11-a shows a foreign matter detection device (circuit) mounted on a wireless power transmitter according to an embodiment of the present invention. FIG. 1 is a diagram for explaining the basic structure of a transmission line.

[0213] Referring to FIG. 11-a, a foreign substance detection device (circuit) 1190 includes a power supply unit 1191, a drive unit 1192, resonance capacitor 1193, transmission coil 1194, quality factor measurement unit 1195 , a demodulation unit 1196 and a control unit 1197.

[0214] The power supply unit 1191 can receive external power and supply it to the driving unit 1192 .

[0215] The driving unit 1192 converts the DC power applied from the power supply unit 1191 into AC power and controls The strength of the AC power can be adjusted according to the control signal of the driving unit 1197. is a frequency oscillator that generates a specific frequency signal and a frequency generated by the frequency oscillator. The amplifier may include an inverter for amplifying the amplified AC signal.

[0216] The driving unit 1192 changes the frequency (operating frequency) of the AC signal in response to a control signal from the control unit 1197. At least one of the wave number, duty, and amplitude can be changed.

[0217] The quality factor measurement unit 1195 measures the inductance change ( or voltage or current) to measure the quality factor value for the transmitting coil. The measured current quality factor value is transmitted to the control unit 1197.

[0218] The demodulation unit 1196 demodulates the signal received from the wireless power receiver and transmits the demodulated signal to the control unit 1197. As an example, the demodulator 1196 demodulates the FOD status packet and outputs it to the controller 1197. It can be transmitted.

[0219] The control unit 1197 receives the quality factor value measured by the quality factor measurement unit 1195 and stores it in a memory. The control unit 1197 may store the recorded quality factor value in the corresponding memory. The control unit 1197 controls the operating frequency of the driving unit 1192. By controlling the operating frequency of the driving unit 1192, the quality factor measuring unit 11 95 can measure the quality factor value for each corresponding operating frequency. Based on the measured quality factor values ​​for each frequency, the frequency corresponding to the maximum quality factor value, i.e., the peak The clock frequency can be determined.

[0220] The control unit 1197 determines whether the FOD status packet includes a reference quality factor value and a maximum quality factor value. Supported operating frequency (reference peak frequency), below the preset value for the reference quality factor value For example, the operating frequency at which a quality factor value of 5% or less is measured with respect to the reference quality factor value. determining a quality factor critical value for the corresponding wireless power receiver based on at least one of the frequencies; It is possible.

[0221] The control unit 1197 determines the quality factor critical value and the quality factor measured by the quality factor measurement unit 1195. and / or the received operating frequency (critical frequency). and the measured or calculated operating frequency, e.g. the operating frequency (peak The quality factor is measured at a frequency of operation that is less than 5% of the reference quality factor value. It is possible to determine whether FO is present in the electric field.

[0222] According to another embodiment of the present invention, the control unit 1197 can also measure the quality factor value. In this case, the control unit 1197 changes the operating frequency within the preset operating frequency range. In one embodiment, the control unit 1197 may measure another quality factor value. The voltage difference across the 1193 can be used to measure the quality factor value, but is not limited to this. do not have.

[0223] According to an embodiment of the present invention, the quality factor measurement unit 1195 is The circuit may include a circuit configuration that measures the voltage of the input terminal and transmits the voltage to the controller 1197.

[0224] The quality factor values ​​measured by the control unit 1197 are the voltage, current, resistance, and impedance of the electric circuit. LCR Meter measures at least one of impedance, capacitance and quality factor values The value may correspond to a quality factor value of the transmit coil measured using a measuring instrument such as r.

[0225] The control unit 1197 determines whether to continue charging or not depending on the result of the determination as to whether or not a foreign substance is present. Alternatively, charging can be interrupted and the selection step can be repeated.

[0226] FIG. 11-b shows a foreign substance detection device (circuit) in a wireless power transmitter according to another embodiment of the present invention. FIG. 11-c is a diagram for explaining a structure (an expanded embodiment of FIG. 11-a).

[0227] Referring to FIG. 11B, a foreign substance detection device 1100 includes a power supply unit 1101, a DC / DC converter, DC-DC Converter 1110 (optional), Inverter 1120, a resonant circuit 1130, a measuring unit 1140, a communication unit 1160, and an alarm The embodiment may include a control unit 1180 and a control unit 1175 (optional). The foreign substance detection device 1100 can be attached to a wireless power transmission device.

[0228] The resonant circuit 1130 includes a resonant capacitor 1131 and an inductor or a transmitting coil 113 2 or a transmitting antenna, and the communication unit 1160 includes a demodulation unit 1161 and a modulation unit 1162. It can comprise at least one of.

[0229] The power supply unit 1101 receives DC power via an external power supply terminal and converts it into a DC / DC converter 1 This can be transmitted to 110.

[0230] The DC / DC converter 1110 receives the input from the power supply unit 1101 under the control of the control unit 1180. The strength of the DC power to be supplied can be converted to a specific strength of DC power. The current / direct current converter 1110 may be a variable voltage converter capable of adjusting the voltage strength. This is not limited to the above.

[0231] The inverter 1120 can convert the converted DC power into AC power. The inverter 1120 converts the input DC power signal into It can be converted into an AC power signal and output.

[0232] As an example, the inverter 1120 is a full bridge circuit. It can include, but is not limited to, a half bridge. ge).

[0233] As another example, the inverter 1120 may be used in both a half-bridge circuit and a full-bridge circuit. In this case, the control unit 1180 controls the inverter 1120 to Dynamically determines whether to operate as a half-bridge or full-bridge. It is possible.

[0234] According to an embodiment of the present invention, a wireless power transmitting apparatus transmits power required by a wireless power receiving apparatus. The bridge mode of the inverter 1120 can be adaptively controlled according to the strength of the power. Here, the bridge mode includes a half-bridge mode and a full-bridge mode. For example, when the wireless power receiving device requires a low power of 5 W, the control unit 1180 The inverter 1120 can be controlled to operate in half-bridge mode. When the line power receiving device requires 15 W of power, the control unit 1180 operates in full-bridge mode. It can be controlled to operate.

[0235] As another example, the wireless power transmitter may be configured to adaptively switch to a bridge mode according to a sensed temperature. and drive the inverter 1120 in the determined bridge mode. The temperature of the wireless power transmitter increases while transmitting wireless power in half-bridge mode. If the predetermined reference value is exceeded, the control unit 1180 deactivates the half-bridge mode and In other words, the wireless power transmission can be controlled to activate the self-bridge mode. The device increases the voltage through a full bridge circuit to transmit the same amount of power, creating a resonant current. The intensity of the current flowing through the circuit 1130 is reduced, thereby reducing the internal temperature of the wireless power transmission device. can be controlled so as to be maintained at or below a predetermined reference value.

[0236] In general, the amount of heat generated by electronic components installed in electronic devices depends on the amount of heat applied to the electronic components. It may be more sensitive to the magnitude of the current than to the magnitude of the voltage.

[0237] In addition, the inverter 1120 can not only convert DC power to AC power, It is also possible to change the strength of the AC power.

[0238] For example, the inverter 1120 generates AC power under the control of the control unit 1180. Reference Alternating Current You can also adjust the frequency of the AC signal to adjust the strength of the AC power output. To this end, the inverter 1120 generates a reference AC signal having a specific frequency. However, this is only one embodiment; in other examples, A frequency oscillator is configured separately from the inverter 1120 and is connected to one side of the foreign matter detection device 1100. It can be mounted.

[0239] As another example, the foreign substance detection device 1100 may include a switch provided in the inverter 1120. The gate driver (not shown) for controlling the switch is further included. In this case, the gate driver can be configured by at least one and receiving one pulse-width modulated signal, and outputting an output in response to the received pulse-width modulated signal. The control unit 1180 can control the switch of the inverter 1120. The duty cycle of the signal, i.e. the duty rate (D The output voltage of the inverter 1120 is controlled by controlling the uty rate and phase. The control unit 1180 can control the strength of the power received from the wireless power receiving device. Adaptively adjusting the duty cycle and phase of the pulse width modulated signal in response to a feedback signal can be controlled.

[0240] The measurement unit 1140 measures both of the resonance capacitors 1131 in response to a control signal from the control unit 1180. At least one of the voltage, current, and impedance of the resonant circuit 1130 is measured. The quality factor value and the peak frequency value can be measured or calculated. The quality factor value and the inductance value are transmitted to the controller 1180, which then determines storing the quality factor value and the peak frequency value transmitted from the measuring unit 1140 in a recording area; It is also possible.

[0241] The measurement unit 1140 outputs a reference operating frequency corresponding to a predetermined reference operating frequency in response to a control signal from the control unit 1180. A quality factor value that corresponds to the measured quality factor, i.e. a reference measured quality factor value, can be measured and stored.

[0242] Alternatively, the measurement unit 1140 may select a specific operating frequency range in response to a control signal from the control unit 1180. The control unit 1180 may measure the quality factor value for each frequency within the range. A peak frequency value, which is the frequency corresponding to the value, can be determined and stored in memory.

[0243] According to an embodiment of the present invention, the control unit 1180 may determine whether to enter the ping stage if an object is detected. The measuring unit 11 is adapted to measure quality factor values ​​at a plurality of different frequencies within the operating frequency band beforehand. The control unit 1180 may control the maximum value of the measured quality factor. The corresponding frequency is identified, and the identified frequency can be determined to be the current peak frequency. .

[0244] If the control unit 1180 receives an FOD status packet from the modulation unit 1162 during the negotiation phase, , a criticality for determining whether or not a foreign object is present based on the information included in the FOD status packet. A value (or critical range) can be determined, where the critical value is the peak frequency value and the quality factor If the determined value is in a critical range, the critical range The range may include at least one of a peak frequency critical range and a quality factor critical range.

[0245] Here, the FOD status packet includes a reference quality factor value or ( and) at least one of the reference peak frequency (F_reference_peak) values. It can be embraced.

[0246] The control unit 1180 determines at least one of the received reference quality factor value and the reference peak frequency value. Critical quality factor and / or peak frequency for determining the presence or absence of foreign matter based on A critical value can be determined. As an example, the value corresponding to 90% of the reference quality factor value is The quality factor critical value may be determined, but is not limited to this, and may be applied to the determination of the critical value. The ratio can be defined differently by the design of those skilled in the art.

[0247] The control unit 1180 receives the current peak frequency (F_current_peak) value and the reference peak frequency (F_current_peak). The reference measurement quality factor value is based on the difference between the peak frequency (F_reference_peak) values. (Q_measured_reference) can be corrected. As an example, The larger the value obtained by subtracting the reference peak frequency from the current peak frequency, the higher the standard measurement quality. The quality factor value can be further increased. For this reason, the current peak frequency (F_curr The difference between the frequency of the reference peak (F_reference_peak) and the A specific correction function that takes the value as a factor can be predefined. As an example, the correction function is It can be, but is not limited to, a linear function, and is defined as a nonlinear function such as an exponential function. As another example, a reference peak may be recorded in a predetermined recording area of ​​the foreign substance detection device 1100. The quality factor correction value corresponding to the current peak frequency movement degree for the frequency is displayed in table format. It can be constructed and maintained.

[0248] The control unit 1180 compares the corrected reference measurement quality factor value with the determined quality factor critical value. By this, foreign matter placed in the charging area can be detected.

[0249] In one example, the control unit 1180 may adjust the corrected reference measurement quality factor value based on the determined quality factor. If it is smaller than the critical value, it can be determined that a foreign substance exists in the charging area. The control unit 1180 detects whether the corrected reference measurement quality factor value is greater than the determined quality factor critical value. If the results are the same, it can be determined that no foreign matter is present in the charging area.

[0250] In addition, the control unit 1180 receives the current peak frequency (F_current_peak) value and the reference The quality factor critical value is based on the difference between the peak frequency (F_reference_peak) values. The control unit 1180 can also correct the reference peak frequency from the current peak frequency value. The larger the subtracted value, the higher the quality factor critical value can be corrected. The control unit 1180 compares the quality factor threshold value with the measured quality factor value. Foreign objects placed in the charging area can be detected.

[0251] When it is determined that a foreign object is present, the control unit 1180 stops power transmission and The alarm unit 1175 is configured to output a predetermined warning alarm indicating that a detection has been made. As an example, the alarm unit 1175 can be a beeper, an LED lamp, This may include, but is not limited to, vibration elements, liquid crystal displays, etc. a predetermined alarm means configured to allow a user to recognize that a detection has been made; It is enough to be prepared.

[0252] The reference quality factor value included in the FOD status packet is a null value specified for standard performance testing. Calculated quality for the corresponding wireless power receiver at a specific position of the charging bed of the line power transmitter A minimum of the factor values ​​can be determined.

[0253] Also, if a foreign object is detected during the negotiation stage, the control unit 1180 returns to the selection stage and The quality factor value and / or peak frequency within the operating frequency band for a specific operating frequency in a period of In this case, the control unit 1180 can control the measurement unit 1140 to measure the When a foreign substance is detected, the detected foreign substance is compared with the previously determined critical value. It can be determined whether the object has been removed from the electric field.

[0254] If the foreign matter is removed, the control unit 1180 goes to the power transmission step. The demodulation unit 1161 can charge the wireless power receiving device. The demodulator 11 demodulates the in-band signal received from the demodulator 11 and transmits the demodulated signal to the controller 1180. 61 demodulates the FOD status packet shown in FIG. 14 or FIG. 15 to be described later and transmits it to the control unit 1180. can be achieved.

[0255] As described above, the foreign substance detection device 1100 according to the present invention detects an object in the selection stage. If the measured quality factor value is known, the measured quality factor value is adaptively corrected based on the degree of shift in the peak frequency. This has the advantage of significantly reducing the probability of failing to detect foreign substances.

[0256] FIG. 12 is a block diagram for explaining the configuration of a foreign substance detection device according to another embodiment of the present invention. It is.

[0257] Referring to FIG. 12, the foreign substance detection device 1200 includes a measurement unit 1210, a search unit 1220, A communication unit 1230, a determination unit 1240, a correction unit 1250, a detection unit 1260, a storage unit 1270, and and a control unit 1280. The configuration of the foreign substance detection device 1200 described above is It is not essential, and some components may be added or removed.

[0258] If the measurement unit 1210 detects that an object is placed in the charging area in the selection step, the measurement unit Transmission can be interrupted at any time and the quality factor value can be measured at a preset reference operating frequency. For convenience of explanation, the current quality factor value measured at the reference operating frequency is referred to as the measured quality factor. The factor value (Q_measured) is named. The reference operating frequency is the operating frequency It can be set to a specific frequency included in several bands. If the wireless power transmitter equipped with 1200 supports the WPC standard, the standard operating frequency is It may be, but is not limited to, 100KHz and may be defined differently depending on the applicable standard. It is important to be aware that this can also be a problem.

[0259] If the search unit 1220 detects that an object is placed in the charging area during the selection step, the search unit 1220 Transmission may be interrupted and a search may be made for a frequency within the operating frequency band that has a maximum quality factor value. Here, the frequency search offset for searching for the frequency with the maximum quality factor value is can be set in units of 10KHz*k (k is a natural number), but is not limited to this. For the sake of convenience, the maximum quality factor within the operating frequency band searched after object detection is used below. The frequency having the value F_current_peak is named as the current peak frequency (F_current_peak). On the other hand, the results obtained in a preliminary experiment were obtained when only the wireless power receiver was placed in the charging area. The frequency with the maximum quality factor value obtained is called the reference peak frequency (F_reference_p We decided to name it eak.

[0260] If a foreign object is placed in the charging area along with the wireless power receiver, it will be detected within the operating frequency band. The frequency with the highest quality factor value obtained is the frequency when only the wireless power receiver is placed in the charging area. It may have a large value compared to the obtained reference peak frequency.

[0261] The measurement quality factor value measured by the measurement unit 1210 and the measurement quality factor value searched for by the search unit 1220 are The obtained current peak frequency value can be stored in a predetermined recording area of ​​the memory unit 1270.

[0262] The communication unit 1230 transmits a foreign object detection status packet (FOD( Foreign Object Detection (Status Packet) Here, the foreign substance detection status packet may include a reference peak frequency value. The information may include at least one of information about the quality factor and information about the reference quality factor value. The structure of the quality detection status packet will become clearer with reference to the description of FIGS. 14 and 15 below. It would be.

[0263] The determination unit 1240 determines whether or not a foreign object is detected based on the reference quality factor value included in the foreign object detection status packet. It is possible to determine the quality factor thresholds for determining whether quality exists. The quality factor critical value can be determined to be 10% smaller than the reference quality factor value. This is only one example, and other ratios may be applied according to the design objectives of those skilled in the art.

[0264] The correction unit 1250 calculates the current peak frequency (F_current_peak) and the reference peak The quality factor threshold (Q _threshold) can be corrected. For example, from the current peak frequency value The larger the value obtained by subtracting the reference peak frequency value, the more the quality factor critical value increases. For this purpose, the current peak frequency (F_current_peak) and the reference peak frequency (F_current_peak) are A specific correction function is used as a factor to determine the difference between the reference peak frequencies (F_reference_peak). As an example, the correction function can be a linear function. It can also be defined as a nonlinear function such as an exponential function.

[0265] According to another embodiment of the present invention, the correction unit 1250 calculates the current peak frequency (F_current Only the difference between the reference peak frequency (F_peak) and the reference peak frequency (F_reference_peak) Alternatively, the amount of correction for the reference measurement quality factor value can be determined based on the reference quality factor value instead of the reference measurement quality factor value. For example, if the value obtained by subtracting the reference peak frequency value from the current peak frequency value becomes large, The larger the reference quality factor value is, the greater the correction amount of the quality factor critical value will be. can be done.

[0266] For convenience of explanation, the quality factor critical value corrected by the correcting unit 1250 will be referred to as We will call this the quality factor critical value (Q_threshold_fixed).

[0267] The detection unit 1260 detects the quality factor threshold value determined by the determination unit 1240 and the correction unit 125 0 to determine whether there is any foreign matter in the charging area. As an example, if the current quality factor value is smaller than the corrected quality factor critical value, For example, the detector 1260 can determine that a foreign substance is present in the charging area. If the quality factor value is greater than or equal to the corrected quality factor critical value, the detector 1260 detects the charging area. It can be determined that no foreign matter is present.

[0268] The control unit 1280 controls the overall operation of the foreign substance detection device 1200, and in particular, wireless power transmission. The lower components, i.e., the measurement unit 1210, the search unit 1220, and the communication unit 123, are transferred to the 0, the operation of the determination unit 1240, the correction unit 1250, the detection unit 1260, etc. Cut.

[0269] Generally, the reference quality factor measured at the reference operating frequency depends on the type of wireless power receiving device. The value may vary. Also, the maximum product quality within the operating frequency band may vary depending on the type of wireless power receiving device. The frequency values ​​having quality factor values ​​may differ.

[0270] Therefore, the foreign substance detection device 1200 sends a foreign substance detection status packet (FOD (Foreign Item Detection Status Packet) (Ign Object Detection) Status Packet) A reference quality factor value and a reference peak frequency value corresponding to the wireless power receiving device are received. can.

[0271] As described above, the foreign substance detection device 1200 according to the present invention detects an object in the selection step. If the measured quality factor value is known, the measured quality factor value is adaptively corrected based on the degree of shift in the peak frequency. This has the advantage of significantly reducing the probability of failing to detect foreign substances.

[0272] FIG. 13a shows a state transition for detecting a foreign substance in a foreign substance detection device according to an embodiment of the present invention. FIG. 13 is a diagram for explaining the transfer process.

[0273] Referring to FIG. 13a, if an object is detected in the selection step 1310, the foreign object detection device The current quality factor value at the reference operating frequency, i.e. the measured quality factor value (Q_measured) can be measured.

[0274] If an object is detected in the selection step 1310, the foreign object detection device performs a ping step 132. measuring quality factor values ​​for a number of different frequencies within an operating frequency band before entering zero; The frequency at which the measured quality factor value is the maximum, i.e. the current peak frequency (F_curre nt_peak) can be searched for.

[0275] In the ping step 1320, the foreign object detection device pings the wireless power receiver with a predetermined electric potential for identifying the wireless power receiver. A force signal, for example a digital ping, may be transmitted periodically.

[0276] The foreign material detection device stores information about the measured quality factor value and the current peak frequency value. The information can be stored in a fixed recording area.

[0277] If the signal strength indicator is received in the ping step 1320, the foreign object detection device performs an identification and configuration The wireless power receiver is identified in step 1330, and a Various configuration parameters can be set.

[0278] Once the identification and configuration of the wireless power receiver is completed, the foreign object detection device proceeds to negotiation step 134. 0 to carry out the foreign substance detection process.

[0279] Here, the foreign substance detection process can be carried out in the following four steps.

[0280] In a first step, the foreign object detection device detects at least one foreign object from the identified wireless power receiver. A detection status packet can be received. Here, the foreign substance detection status packet can be received by the reference pipe. The information includes at least one of information about a peak frequency value and information about a reference quality factor value. It is possible.

[0281] The information about the reference quality factor value is obtained when the wireless power receiver is turned off. It can mean the quality factor value measured against a reference operating frequency. OFF can mean that no power is being transmitted to the load. The information about the frequency value of the corresponding wireless power receiver in the charging area of ​​a given wireless power transmitter is This means the frequency that has the maximum quality factor value within the operating frequency band when only one frequency is allocated. The wireless power receiver stores the reference peak frequency value in advance and uses it during the negotiation stage. It can be transmitted to a wireless power transmitter.

[0282] In the second step, the foreign matter detection device determines whether or not a foreign matter is present based on the received reference quality factor value. A quality factor critical value for the judgment can be determined.

[0283] In the third step, the foreign object detector determines the frequency of the current peak based on the difference between the current peak frequency and the reference peak frequency. Correct (or compensate) the reference measurement quality factor (Q_measured_reference) value by For example, the corrected Q_measu The red_reference value is currently matched to the Q_measured_reference value. It may be the difference between the peak frequency value and the reference peak frequency value, or it may be a corrected The Q_measured_reference value is The difference between the current peak frequency value and the reference peak frequency value is multiplied by a specified weighting value. It may be an addition.

[0284] In step 4, the foreign material detector compares the quality factor critical value with the calibrated reference measurement quality factor value. This makes it possible to determine whether or not a foreign substance is present.

[0285] If the foreign object is detected, the foreign object detection device stops the power transmission and selects the selection step 13. Alternatively, an indicator can be wirelessly transmitted to indicate the presence of foreign matter. The wireless power receiver can transmit the power to the power receiver, and the wireless power receiver can transmit the power to the power receiver. Power Transfer) or ignore it to continue charging. On the other hand, if the result of the judgment is that no foreign object is present, the next step can be taken. If not, the foreign object detection device proceeds to power transmission step 1350 to transmit power to the corresponding wireless power receiver. Wireless charging can then begin.

[0286] FIG. 13b shows a state for detecting a foreign substance in a foreign substance detection device according to another embodiment of the present invention. FIG. 13 is a diagram for explaining a transition process.

[0287] Referring to FIG. 13b, if an object is detected in the selection step 1311, the foreign object detection device The current quality factor value at the reference operating frequency, i.e. the measured quality factor value (Q_measured) can be measured.

[0288] If an object is detected in the selection step 1311, the foreign object detection device performs a ping step 132. 1, measuring quality factor values ​​for a plurality of different frequencies within an operating frequency band before entering the The frequency at which the measured quality factor value is the maximum, i.e. the current peak frequency (F_curre nt_peak) can be searched for.

[0289] In a ping step 1321, the foreign object detection device pings a predetermined power source for identifying the wireless power receiver. A force signal, for example a digital ping, may be transmitted periodically.

[0290] The foreign material detection device stores information about the measurement quality factor value and the current peak frequency value in a predetermined storage medium. The information can be stored in a recording area.

[0291] If the signal strength indicator is received in the ping step 1321, the foreign object detection device performs identification and configuration. The wireless power receiver is identified in step 1331, and a Various configuration parameters can be set.

[0292] When the identification and configuration of the wireless power receiver is completed, the foreign object detection device performs negotiation step 13. 41 to carry out the foreign substance detection process.

[0293] Here, the foreign substance detection process can be carried out in the following four steps.

[0294] In a first step, the foreign object detection device detects at least one foreign object from the identified wireless power receiver. A detection status packet can be received. Here, the foreign substance detection status packet can be received by the reference pipe. The information includes at least one of information about a peak frequency value and information about a reference quality factor value. It is possible.

[0295] The information about the reference quality factor value is obtained when the wireless power receiver is turned off. It can mean the quality factor value measured against a reference operating frequency. OFF can mean that no power is being transmitted to the load. The information about the frequency value of the corresponding wireless power receiver in the charging area of ​​a given wireless power transmitter is This means the frequency that has the maximum quality factor value within the operating frequency band when only one frequency band is deployed. The wireless power receiver stores the reference peak frequency value in advance, and the negotiation step 1341 This can then be transmitted to a wireless power transmitter.

[0296] In the second step, the foreign matter detection device determines whether or not a foreign matter is present based on the received reference quality factor value. A quality factor critical value for the judgment can be determined.

[0297] In the third step, the foreign matter detection device compares the quality factor threshold value with the measured quality factor value to determine whether foreign matter is present. It is possible to determine whether or not it exists.

[0298] If it is determined that a foreign object is present, the foreign object detection device according to the embodiment stops power transmission. , the process may return to selection step 1310. A predetermined foreign matter sensing indicator indicating the presence of the foreign matter may also be transmitted to the wireless power receiver. Here, if the wireless power receiver receives a foreign object detection indicator, it stops power transmission ( End of Power Transfer) or continue charging. Therefore, the foreign substance detection indicator is ignored, i.e., an Ack response signal corresponding to the foreign substance detection indicator is not transmitted. You can also move on to the next stage.

[0299] On the other hand, if the result of the judgment is that no foreign matter is present, the foreign matter detection device sets the reference peak frequency value It is possible to determine whether the message has been received.

[0300] According to an embodiment of the present invention, the foreign substance detection device detects a reference peak included in a foreign substance detection status packet. If the peak frequency value is greater than 0, it is determined that the reference peak frequency value has been received. This can be done.

[0301] If the reference peak frequency value is not received, the foreign object detection device proceeds to power transfer step 135. 0 to start wireless charging for the corresponding wireless power receiver.

[0302] When the reference peak frequency information is received, the foreign substance detection device performs a calculation based on the reference peak frequency value. Based on this, the peak frequency threshold can be determined.

[0303] In step 4, the foreign matter detector compares the peak frequency threshold value with the current peak frequency value to detect the foreign matter. It is possible to determine whether or not a substance exists. If the current peak frequency value is greater than the peak frequency threshold, If the threshold is exceeded, it is determined that a foreign object is present, and the foreign object detection device interrupts power transmission and proceeds to the selection stage. 1311. Or, you can use an indicator to indicate the presence of foreign matter. The wireless power receiver can transmit the power to the wireless power receiver, and the wireless power receiver can transmit the power to the wireless power receiver. Power Transfer) or to continue charging, It is also possible to ignore it (transmit Ack) and move on to the next stage. If not, the foreign object detection device enters power transmission step 1351 to transmit the corresponding wireless power receiver. Then, wireless charging can be started.

[0304] In yet another embodiment, in the embodiment of FIG. 13b, the foreign material detection device determines whether the foreign material is present based on the quality factor value. Before performing the foreign object detection process, check whether the reference peak frequency value is received from the wireless power receiver. The process of acknowledging the identity of the person who has been arrested may be carried out first.

[0305] Here, if the reference peak frequency value is received as a result of the confirmation, the foreign substance detection device The foreign substance detection process based on the index and the foreign substance detection process based on the peak frequency were performed. It is possible to determine whether or not a signal is present.

[0306] On the other hand, if the reference peak frequency value is not received, the foreign matter detection device It is also possible to determine whether or not a foreign substance exists by only performing the foreign substance detection process based on the quality factor value.

[0307] In the case where the foreign substance detection process is performed differentially depending on whether or not the reference peak frequency is received, This has the advantage that the foreign object detection process can be performed in the way that the radio receiver prefers. A foreign object detection method optimized for the device to which the power receiver is attached is preset at the manufacturing stage. This is expected to improve the accuracy of detecting foreign substances. Of course, the foreign object detection method corresponding to the wireless power receiver according to the predetermined menu setting is Note that whether the reference peak frequency information is transmitted or not may be changed. In an embodiment, the wireless power receiver identifies the type and characteristics of the wireless power transmitter. It is also possible to determine a method of detecting foreign substances that is optimized for the identified types and characteristics. In this case, the wireless power receiver adaptively adjusts the reference peak frequency according to the determined foreign object detection method. It is also possible to determine whether or not numerical information can be transmitted.

[0308] FIG. 13c is a diagram illustrating a process of detecting foreign matter according to another embodiment of the present invention. .

[0309] The wireless power transmitter measures the quality factor value of the co-propagating circuit when an object is detected in the charging area. The quality factor of a resonant circuit is determined by the frequency at which AC power of a particular frequency is applied to the resonant circuit. This can mean the amplification ratio of the input and output voltages by the resonant capacitor when Please refer to the explanation of FIG. 11-a and FIG. 11-b. Here, the operation of the wireless power transmitter It is possible to measure the quality factor value for each frequency within the operating frequency range.

[0310] The wireless power transmitter determines a current quality factor value and a peak frequency (measured) according to the quality factor measurement. The frequency at which the maximum quality factor value was measured within the determined frequency range is determined and stored in memory. It is possible.

[0311] The wireless power transmitter may receive a foreign object detection status packet. For the knowledge state packet, please refer to the explanation of Figures 14-a and 14-b.

[0312] The wireless power transmitter determines a quality factor critical value based on the received reference quality factor value. This can be done.

[0313] The wireless power transmitter determines whether a foreign object is present by using the quality factor critical value and the measured quality factor value. It is possible to determine whether or not

[0314] For example, if the current quality factor value is greater than or equal to the quality factor critical value, the wireless power transmitter It can be determined that the substance exists. If the current quality factor value is smaller than the quality factor critical value, In this case, the wireless power transmitter includes information about the reference peak frequency in the foreign substance detection status packet. It is possible to determine whether the signal is included (see FIG. 14 described later).

[0315] If the foreign substance detection status packet does not include information about the reference peak frequency, If so, the wireless power transmitter can determine that no foreign object is present. Next steps for transmission (e.g. calibration or power transformer fer) can be advanced.

[0316] When the information about the reference peak frequency is included, the wireless power transmitter It is now possible to better determine whether or not foreign matter is present based on information about peak frequencies. The line power transmitter can determine the peak frequency threshold using the reference peak frequency value. The wireless power transmitter compares the peak frequency threshold with the current peak frequency and If the wave number is equal to or greater than the peak frequency threshold, it can be determined that a foreign substance is present. , In the following case, if the current peak frequency is less than the peak frequency critical value, the wireless power transmitter It can be determined that no foreign matter is present.

[0317] Depending on the result of the judgment on the presence of foreign matter, the wireless power transmitter may proceed with wireless power transmission or A break can be determined.

[0318] In still another embodiment, the step of determining whether or not a foreign substance is present based on the quality factor value and the peak circumference The procedure for determining whether or not foreign matter exists based on wave numbers can be changed. That is, the presence or absence of foreign matter is judged based on the peak frequency, and then the presence or absence of foreign matter is judged based on the quality factor value. By further advancing the judgment of the presence or absence of foreign substances, the ability to detect foreign substances can be improved. Cut.

[0319] FIG. 13d is a diagram illustrating a process of detecting foreign matter according to another embodiment of the present invention. .

[0320] Referring to FIG. 13d, the wireless power transmitter detects an object in the charging area and then detects the resonant circuit. The quality factor of a co-axial circuit can be measured by measuring the quality factor of the circuit. It means the amplification ratio of the input / output voltage by the resonant capacitor when power is applied to the resonant circuit. This can be seen in the explanation of Figures 11-a and 11-b. Therefore, the quality factor value for each frequency can be measured within the operating frequency range of the wireless power transmitter. do.

[0321] The wireless power transmitter may store the quality factor values ​​measured for each frequency in a predetermined memory. can.

[0322] The wireless power transmitter can receive the foreign object detection status packet.

[0323] Here, the foreign substance detection status packet is a packet for a frequency at which the maximum quality factor value within the operating frequency is measured. Information on the reference peak frequency corresponding to the number and the reference product corresponding to the corresponding maximum quality factor value It may include information about the quality factor value.

[0324] The wireless power transmitter determines a quality factor critical value based on the received reference quality factor value. This can be done.

[0325] The wireless power transmitter determines whether or not a foreign object is present by using the quality factor critical value and the measured quality factor value. The quality factor value measured at this time is the received reference peak frequency. The quality factor value measured at the frequency corresponding to the wave number can be used. Since the calculated quality factor value is stored in the memory, the wireless power transmitter can calculate the received reference peak and identifying a frequency corresponding to the frequency and measuring a quality factor value corresponding to the identified frequency. can be read from memory.

[0326] The frequency at which the quality factor value changes most depending on the presence or absence of foreign matter is the reference peak frequency. Therefore, the wireless power receiver is measured at the reference peak frequency and the reference peak frequency. The quality factor value is transmitted to the wireless power transmitter, and the wireless power transmitter determines whether or not the quality factor value is based on the received information. The presence or absence of foreign matter can be determined by the above. The reference quality factor value corresponding to the most significantly changed reference peak frequency is compared with the current quality factor value. In comparison, the ability to detect foreign substances can be improved. The current quality factor value may be measured before the ping step, but is not limited to this.

[0327] In yet another embodiment of the present invention, the wireless power transmitter may include a foreign object detection status packet. The presence or absence of a foreign substance can be determined based only on the information about the reference peak frequency.

[0328] The frequency corresponding to the maximum quality factor value among the quality factor values ​​measured before the ping stage is the reference ping frequency. If the frequency is greater than the peak frequency (which can be determined by taking into account a certain margin of error), can be determined to exist.

[0329] FIG. 14-a illustrates a message structure of an FOD status packet according to one embodiment of the present invention. This is a diagram for

[0330] Referring to FIG. 14-a, the FOD status packet message 1400 is 2 bytes long. 1401 field, which is 6 bits long, Mode 1402 field and 1-byte long reference quality factor value ce Quality Factor Value) 1403 field. This can be done.

[0331] As shown in drawing number 1404, the mode 1402 field is set to binary '00'. If so, all bits in the first data 1401 field are recorded as 0, and the reference quality factor value The power consumption of the wireless power receiver in the 1403 field is measured and determined when the receiver is turned off. On the other hand, the mode 1402 field is set to two If the binary number is set to '01', the first data 1401 field indicates the wireless The frequency having the maximum quality factor value within the operating frequency band when only the input receiver is placed is defined as the frequency. Reference Peak Frequency Value Here, the reference quality factor value 1403 field contains the information corresponding to the quality factor value. The reference quality factor value determined by measuring the wireless power receiver when it is turned off The reference peak recorded in the first data 1401 may be recorded. The resolution of the frequency values ​​can be determined by the size of the operating frequency band.

[0332] As shown in FIG. 14a, the first data 1401 can have values ​​from 0 to 63. If the operating frequency band is from 100 KHz to 260 KHz, the first data 140 If 1 is 0, it means that the reference peak frequency is 100 KHz, and the first data 1401 is 63 This means that the reference peak frequency is 260KHz. The resolution of the clock frequency value is 160KH obtained by dividing the operating frequency bandwidth by the number of first data 1410. It can be determined that z / 64 = 2.5KHz.

[0333] Alternatively, the operating frequency band for quality factor measurement may be 87KHz to 150KHz. Here, the first data 1401 includes any frequency between 87 KHz and 150 KHz. You can also specify a value.

[0334] FIG. 14-b illustrates a message structure of an FOD status packet according to another embodiment of the present invention. This is a diagram for explaining the method.

[0335] Referring to FIG. 14-b, the FOD status packet message 1410 is 2 bytes long. 1411 field, which is 6 bits long, Mode 1412 field and 1-byte long reference quality factor value ce Quality Factor Value) 1413 field. This can be done.

[0336] As shown in drawing number 1414, the mode 1412 field is set to binary '00'. If so, the first data 1401 field indicates that only the corresponding wireless power receiver is located in the charging area. The reference peak frequency, which is the frequency with the maximum quality factor value in the operating frequency band under the condition Information corresponding to the value (Reference Peak Frequency Value) If the first data 1411 is 0, the foreign matter detection device is disabled. It can be determined that the line power receiver did not transmit the reference peak frequency value, where: The reference quality factor value 1413 field is the value when the wireless power receiver is turned off. Information corresponding to the reference quality factor value determined by measuring the first quality factor value may be recorded. The resolution of the reference peak frequency value recorded in data 1401 is based on the size of the operating frequency band. The determination can be made based on the above.

[0337] As shown in FIG. 14-b, the first data 1411 may have a value from 1 to 63. If the operating frequency band is 100KHz to 260KHz, the first data 14 If 11 is 1, it means that the reference peak frequency is 100KHz, and the first data 1411 is 6 3, it can mean that the reference peak frequency is 260KHz. The resolution of the peak frequency value is 160K, which is the operating frequency bandwidth divided by the number of first data 1411. It can be determined that the frequency is Hz / 63=2.54KHz.

[0338] Alternatively, the operating frequency band for quality factor measurement may be 87KHz to 149KHz. Here, the first data 1411 is a frequency value between 87 KHz and 149 KHz. You can also give instructions.

[0339] In yet another embodiment, the foreign substance detection status packet of FIG. 14-a and FIG. 14-b is information about the reference peak frequency corresponding to the frequency at which the maximum quality factor value in the and information about a reference quality factor value, which is the quality factor value corresponding to the corresponding maximum quality factor value. The information value and the reference quality factor value for the reference peak frequency can be calculated based on the information value and the reference quality factor value for the wireless power receiving device. This value can be information stored in the memory of the receiver when it is manufactured to a specific radio power level. The value may be a value previously measured using a transmitter. Here, a specific wireless power transmitter is a standard transmitter. It is a transmitter used for certification purposes, and the actual product has design differences based on the standard transmitter. The measurement values ​​of the standard transmitter can be corrected to take into account the characteristic differences.

[0340] When the wireless power transmitter receives the FOD status packet of FIG. 14, it sets the reference quality factor value and pin The quality factor values ​​measured in the ping step 520 (or before the ping step) are compared to determine whether or not foreign matter is present. (method 1), or the reference peak frequency and ping step 520 (or It is also possible to determine the presence or absence of foreign matter by comparing the peak frequencies measured during the scanning phase (before the scanning phase). This is possible (Method 2, embodiment in FIG. 11).

[0341] Alternatively, the presence or absence of foreign matter can be determined using a combination of methods.

[0342] In one embodiment, the wireless power transmitter can determine whether or not a foreign object is present using Method 1. Here, two thresholds (threshold 1: Q_Thres hold1 and threshold value 2: Q_Threshold2) can be determined, where , Critical Value 1 has a value greater than Critical Value 2.

[0343] If the quality factor value measured before the ping step 520 is less than the critical value 2, the wireless power transmission The machine can determine that a foreign substance is present.

[0344] If the quality factor value measured before the ping step 520 is smaller than the critical value 1 and larger than the critical value 2, If the two are the same, the wireless power transmitter can determine whether or not a foreign object is present using method 2. .

[0345] FIG. 15 is a block diagram illustrating a message structure of an FOD status packet according to another embodiment of the present invention. This is a diagram of the

[0346] Referring to FIG. 15, the FOD status packet message 1500 has a length of 2 bytes. A 6-bit long Reserved 1501 field, a 2-bit The Length Mode 1502 field and the 1-byte Length Reference 1503 field. All bits in the 01 field are recorded as '0'.

[0347] As shown in drawing number 1504, the mode 1502 field is set to binary '00'. If this is the case, the reference value 1503 field will contain the state in which the wireless power receiver is turned off. Information corresponding to the reference quality factor values ​​determined by measuring the quality factor may be recorded.

[0348] On the other hand, if the mode 1502 field is set to binary '01', the reference value 1503 field The field is designed so that only the corresponding wireless power receiver is placed in the charging area and the The reference peak frequency value (Reference Peak Frequency) means the frequency with the highest quality factor value. Information corresponding to the frequency value (ak) can be recorded. The reference peak frequency is set for a wireless device with no foreign objects in the charging area and with the power turned off. Only the power receiver can be searched for.

[0349] In this embodiment, the foreign object detection device (or the wireless power transmission device) is connected to multiple FOs in the negotiation stage. A D state packet is received, and a reference peak frequency value and a reference A quality factor value can be obtained.

[0350] For example, if the value recorded in the reference value 1503 is the reference peak frequency, The resolution of the wave number is determined by the size of the operating frequency band of the corresponding wireless power transmission device, i.e., the operating frequency This can be determined based on the bandwidth.

[0351] If the operating frequency bandwidth of the wireless charging system is 256KHz, the reference peak frequency is The resolution of the wave number can be 256KHz / 128=2KHz.

[0352] As shown in FIG. 15, the base value 1503 field has a length of 1 byte. The sub-value 1503 can have a value from 0 to 127. As an example, A wireless power transmitter whose frequency band is from 100KHz to 356KHz has a mode value 1502 of two. The FOD status packet is hexadecimal '01' and the base value 1503 is set to '0x05'. If the wireless power transmitter receives the signal, the reference peak frequency corresponding to the wireless power receiver is 10 It can be recognized that 0KHz+5*2KHz=110KHz.

[0353] FIG. 16 illustrates a method for detecting a foreign object in a wireless power transmission device according to an embodiment of the present invention. 1 is a flowchart for

[0354] Referring to FIG. 16, the wireless power transmitting device detects an object placed in the charging area in the selection step. If the quality factor value is not known, the quality factor value corresponding to the reference operating frequency is measured before entering the ping stage. In this case, the transmission coil The voltage should be 0.5Vrms~2Vrms. Here, rms is the root mean square. (are).

[0355] In addition, the wireless power transmission device has been measured at a number of different frequencies within the operating frequency band. A current peak frequency, which is a frequency having a maximum quality factor value among the quality factor values, is searched for and a predetermined The current peak in the operating frequency band can be stored in the recording area (S1603). A frequency offset for determining the frequency at which the quality factor value is measured for the frequency search. Note that (or the number of frequencies) may vary depending on the design of the art. No (S1603).

[0356] In this embodiment, the operating frequency band is 87KHz to 150KHz, and the standard operating frequency can be, but is not limited to, 100KHz.

[0357] When the wireless power transmitter completes the current peak frequency search, it enters the ping stage and transmits the wireless power. A digital ping signal can be sent wirelessly to identify the power receiver.

[0358] When the wireless power transmitter receives a signal strength indicator corresponding to the digital ping signal, The identification and configuration stage is entered, and when the identification and configuration of the wireless power receiver are completed, the negotiation stage is entered. The user can then transition to the next floor (S1604).

[0359] The wireless power transmitter determines whether a foreign object is present based on the FOD status packet received during the negotiation phase. A critical value (or critical range) for determining the presence or absence can be determined (S1605). Here, the threshold value is determined based on the reference quality factor value included in the FOD status packet. It can be, but is not limited to, a quality factor critical value.

[0360] The wireless power transmitter uses the reference peak included in the FOD status packet received in the negotiation stage. The product is measured according to the reference operating frequency based on the difference between the frequency value and the current peak frequency value. Correction (or compensation) of the quality factor value, i.e. the reference measurement quality factor value ) (S1606).

[0361] The wireless power transmission device compares the corrected reference measurement quality factor value with the determined quality factor critical value. By comparing the two, it is possible to determine whether or not a foreign substance is present (S1607).

[0362] If a foreign object is detected, the wireless power transmitting device stops transmitting the power signal and It is possible to control the output of a predetermined warning alarm to indicate that a quality problem has been detected. (S1608 and S1609).

[0363] If it is determined in step 1608 that no foreign object is present, the wireless power transmitting apparatus The power transmission step can be entered and charging of the corresponding wireless power receiver can be started (S16 08 and S1610). Here, power transmission and charging are performed before the wireless power receiver starts charging. A calibration process is also carried out to optimize various configuration parameters required for force control. It can also be executed.

[0364] FIG. 17 shows the relationship between the reference peak frequency for each receiver type and the arrangement of foreign matter according to an embodiment of the present invention. 13 is a table showing experimental results for explaining changes in peak frequency.

[0365] Referring to FIG. 17, the reference values ​​obtained when only the wireless power receiver was placed in the charging area were The peak frequency 1710 and the quality factor value 1720 measured at the corresponding reference peak frequency are received. This indicates that the operation varies depending on the machine type.

[0366] In particular, referring to drawing numbers 1710 and 1730, only the wireless power receiver is in the charging area. The peak frequency 1730 when no foreign object is placed is the same as the peak frequency 1730 when only the wireless power receiver is placed. It can be seen that the peak frequency is greater than the peak frequency of 1710 in the normal state.

[0367] Also, referring to drawings 1720 and 1740, the receiver and foreign matter are both in the charging area. The quality factor measured when present is the quality factor measured when only the receiver is placed. It can be seen that the value is reduced compared to the

[0368] Also, referring to drawing number 1750, the position of the foreign object placed in the charging area is different from the center. As the distance increases, the peak frequency decreases but the quality factor value increases.

[0369] FIG. 18 shows the quality factor value and peak power according to the arrangement of foreign objects in the wireless charging system according to the present invention. 13 is a graph showing the experimental results showing changes in frequency.

[0370] Referring to FIG. 18, when the first receiver and a foreign object are placed in the charging area, the peak frequency increases by Δf compared to when only the first receiver is placed in the charging area. To do this, △f is the peak frequency shift value (Peak Frequency Shift Value On the other hand, the first receiver and the foreign substance were placed in the charging area. The quality factor value measured at the peak frequency corresponding to the state, i.e., the current peak frequency, is the first The peak frequency is measured at the reference peak frequency, which corresponds to the receiver alone. This means that the quality factor value decreases by ΔQ from the previously calculated value. is named the Quality Factor Shift Value. I decided to do so.

[0371] As shown in FIG. 18, the remaining second to fourth receivers are also The results are similar to the experimental results.

[0372] According to an embodiment of the present invention, the foreign substance detection device is The reference measurement quality factor value may also be corrected based on the peak frequency shift value As the sum of the quality factor shift value and the reference quality factor value increases, the ratio of the reference quality factor value to the reference quality factor value increases.

[0373] As an example, the foreign substance detection device may determine a quality factor value ( Hereinafter, for convenience of explanation, the first maximum quality factor value is received from the wireless power receiver. If an object is detected during the selection step, the foreign object detection device selects the operating frequency band. It is now possible to search for the peak frequency by measuring the quality factor value at multiple different frequencies in Here, the quality factor value corresponding to the current peak frequency found can be set to the second maximum quality factor value. The foreign substance detection device detects the first maximum quality factor value and the second maximum quality factor value. The value obtained by subtracting the above can be determined as the quality factor transfer value. The status packet further includes a predetermined data field for recording said first maximum quality factor value. can be defined.

[0374] In general, in wireless charging systems, the resonance phenomenon occurs at the peak frequency where the quality factor value is the largest. When the resonance phenomenon occurs, the power efficiency is maximized.

[0375] FIG. 19 is a block diagram for explaining the configuration of a foreign substance detection device according to still another embodiment of the present invention. This is a block diagram.

[0376] Referring to FIG. 19, a foreign substance detection device 1900 includes a peak frequency search unit 1910, an output A voltage measuring unit 1920, a quality factor slope determining unit 1930, a foreign substance detecting unit 1940 and a control unit 1 950. The configuration of the foreign substance detection device 1900 described above is not necessarily required. It is not essential and some configurations can be added or removed.

[0377] The peak frequency search unit 1910 detects that an object is placed in the charging area in the selection step. If the power transmission is interrupted, the frequency with the maximum quality factor value within the operating frequency band is selected. Here, a frequency for searching for a frequency having a maximum quality factor value can be The search offset can be set in units of 10KHz*k (k is a natural number). The frequency search offset may be defined in smaller or larger units, without being limited to For the sake of convenience, the maximum quality within the operating frequency band searched after object detection is used below. The frequency with the factor value is named the current peak frequency (F_current_peak). On the other hand, a preliminary experiment was conducted with only the wireless power receiver placed in the charging area. The frequency with the maximum quality factor value obtained is called the reference peak frequency (F_reference We decided to name it _peak.

[0378] The output voltage measurement unit 1920 measures the output voltage level at a specific frequency within the operating frequency band. As an example, the frequency at which the output voltage level is measured can be within the operating frequency band. The start frequency (F_start), the current peak frequency being searched, and the end frequency of the operating frequency band. The output voltage level of the resonant circuit may include at least one of the wave number (F_end). This may be, but is not limited to, the strength of the voltage applied to the transmitting coil, and the output voltage level. The position at which is measured may vary depending on the design of the art.

[0379] The quality factor slope determining unit 1930 determines the slope of the particular frequency measured by the output voltage measuring unit 1920. The quality factor slope can be calculated based on the voltage value for each wave number. and the output voltage level measured at the current peak frequency, respectively. Let us name them V_start' and Vc'. Here, the quality factor slope (Q_slop e') is expressed by the following formula, as shown in drawing number 2020 of FIG. 20 described later:

[0380] (Vc'-V_start') / (F_current_peak-F_start)

[0381] It can be calculated as follows.

[0382] In the above-described embodiments of FIGS. 19 to 21, the quality factor slope is calculated based on the measured voltage level. Although the present invention is described as being one embodiment, this is by way of example only and other embodiments of the invention may be practiced in accordance with the same. The quality factor slope can also be calculated based on the quality factor values ​​measured at that frequency. You have to be careful.

[0383] According to another embodiment of the present invention, the output voltage level (Vc') measured at the current peak frequency The quality factor slope (Q_ In this case, the quality factor slope can be calculated using the following formula:

[0384] (Vc'-V_end') / (F_current_peak-F_end)

[0385] It can be calculated as follows.

[0386] For the sake of convenience, the output voltage levels measured at the start frequency and the current peak frequency are shown below. The quality factor slope calculated based on the peak (or quality factor value) is called the first quality factor slope, and the current peak It is calculated based on the output voltage level (or quality factor value) measured at the start and end frequencies. The quality factor slope obtained by the above equation is called the second quality factor slope.

[0387] The foreign matter detection unit 1940 compares the calculated quality factor slope with a predefined critical value. , foreign objects placed in the charging area can be detected.

[0388] As an example, the foreign substance detection unit 1940 may use the calculated first quality factor slope and a previously defined The presence or absence of foreign matter can be determined by comparing the first quality factor slope critical value obtained by the above calculation. Here, the first quality factor slope critical value may have a positive value.

[0389] As another example, the foreign matter detection unit 1940 may use the calculated second quality factor slope as a predefined The presence or absence of foreign matter can be determined by comparing the second quality factor slope critical value obtained. Here, the second quality factor slope critical value may have a positive value.

[0390] The first quality factor slope critical value is included in the foreign object detection status packet of FIG. 15. Here, the first quality factor slope critical value is recorded in the reference value field. However, this is merely an example, and the foreign substance detection status packet may include the first A new field can also be defined to record the quality factor slope critical value.

[0391] As yet another example, the foreign matter detection unit 1940 may detect a first quality factor slope and a second quality factor slope. The average value of the quality factor slope is calculated, and the calculated quality factor slope average value is multiplied by a predefined quality factor slope critical value. It is also possible to judge whether or not there is a foreign substance by comparing the average value with the first quality factor slope. It can be calculated by subtracting the second quality factor slope from the σ and then dividing by two.

[0392] As shown in Figure 20, which will be described later, the quality calculated when only the receiver is placed in the charging area is The absolute value of the quality factor slope is the slope of the quality factor calculated when the receiver and the foreign object are placed together. has a value greater than the absolute value.

[0393] Therefore, the foreign substance detection unit 1940 determines whether the calculated first quality factor slope is the first quality factor slope. If the difference is smaller than the critical value, it can be determined that a foreign substance is placed in the charging area.

[0394] The foreign matter detection unit 1940 detects whether the calculated first quality factor slope is greater than the first quality factor slope critical value. If it is greater than or equal to the value, it can be determined that no foreign matter is present in the charging area.

[0395] As an example, the first quality factor slope critical value is predefined based on the type of the wireless power receiver. The information can be stored in a predetermined recording area of ​​the foreign substance detection device 1950.

[0396] As another example, the first quality factor slope critical value may be the same for all wireless power receivers. It can be done.

[0397] In still another example, the first quality factor slope critical value may be transmitted to the corresponding wireless device via a communication unit (not shown). It may also be received directly from the power receiver. Here, the foreign material detection device 1900 is The foreign object detection status packet (FOD) received from the wireless power receiver on the floor First quality factor via Object Detection) Status Packet) A child slope critical value or / and a second quality factor slope critical value can be obtained.

[0398] The control unit 1950 controls the overall operation of the foreign substance detection device 1900 and controls the foreign substance detection unit 1 If a foreign object is detected by 940, power transmission to the corresponding wireless power receiver is temporarily stopped, A predetermined warning alarm is provided to indicate the presence of a foreign object in the charging area. The alarm unit (not shown) can be controlled by the alarm unit.

[0399] After outputting a warning alarm, the control unit 1950 checks whether the detected foreign matter has been removed from the charging area. If the monitoring result shows that the foreign substance has been removed, In this case, the control unit 1950 cancels the warning alarm and resumes power transmission to the corresponding wireless power receiver. The control can be performed so that

[0400] FIG. 20 shows the slope of the quality factor depending on the presence or absence of foreign matter in the wireless charging system according to the present invention. FIG. 13 is a diagram for explaining the change.

[0401] Referring to FIG. 20, drawing number 2010 shows a state in which only a wireless power receiver is arranged in the charging area. FIG. 2020 shows an example of calculating the quality factor slope in the charging area. In addition, an example of calculating the quality factor slope when a foreign substance is placed is shown in Figure 20. The quality factor slope (Q_slope) calculated when only the wireless power receiver is placed in the area is The quality factor slope (Q_slope') calculated after further foreign matter is placed is small. This indicates that.

[0402] For the sake of convenience, we use Q_slope and Q_slope' as the reference quality factors. We will name them the child slope and the current quality factor slope.

[0403] The quality factor slope critical value according to an embodiment of the present invention is greater than the reference quality factor slope of FIG. The value is determined to be either smaller than the current quality factor slope of drawing number 2020 or larger than the current quality factor slope of drawing number 2020. It can be done.

[0404] FIG. 21-a illustrates a method for detecting a foreign object in a wireless power transmission device according to another embodiment of the present invention. 1 is a flowchart for explaining the process.

[0405] Referring to FIG. 21-a, the wireless power transmitting device detects an object placed in the charging area in the selection stage. It can be sensed (S2101).

[0406] If an object is detected, the wireless power transmitter suspends power transmission before entering the ping phase. The maximum quality factor value is calculated by dividing the total number of quality factors by the number of different frequencies in the operating frequency band. The current peak frequency can be searched for and stored in a predetermined recording area (S2102 ).

[0407] Here, the frequency at which the quality factor value is measured for the current peak frequency search within the operating frequency band is The frequency offset (or number of frequencies) for determining the wave number will vary depending on the design of the art. Also, the operating frequency band is the same as the corresponding wireless charging This may vary depending on the system design and the applicable standards.

[0408] The wireless power transmitter is configured to transmit a power signal to the start frequency and the current peak frequency of the operating frequency band. The corresponding output voltage level can be measured (S2103).

[0409] The wireless power transmitter is configured to transmit power at the output voltage level measured at the start frequency and the current peak frequency. Here, the quality factor slope ( Q_slope') is measured at the current peak frequency (F_current_peak) The output voltage level measured at the start frequency (F_start) from the output voltage level (Vc'). The value subtracted from the peak frequency (V_start') is then divided by the difference between the current peak frequency and the start frequency. That is, the quality factor slope can be calculated by the following formula:

[0410] Q_slope'=(Vc'-V_start') / (F_current_peak -F_start)

[0411] It can be calculated as follows.

[0412] The wireless power transmitting apparatus compares the calculated quality factor slope with a predetermined quality factor slope threshold value. Then, it can be determined whether a foreign substance is present in the charging area (S2105).

[0413] If a foreign object is detected, the wireless power transmitting device stops transmitting the power signal and It is possible to control the output of a predetermined warning alarm to indicate that a quality problem has been detected. (S2106 and S2107).

[0414] If it is determined in step 2105 that no foreign object is present, the wireless power transmitting apparatus The power transmission step can be entered and charging of the corresponding wireless power receiver can be started (S21 06 and S2108).

[0415] FIG. 21-b illustrates a method for detecting a foreign object in a wireless power transmission device according to another embodiment of the present invention. 1 is a flowchart for explaining the process.

[0416] Referring to FIG. 21-b, the wireless power transmitting device detects an object placed in the charging area during the selection stage. can be sensed (S2111).

[0417] If an object is detected, the wireless power transmitter applies a low voltage (e.g., 0.5V~2V) to the inverter 1120 to generate multiple different The quality factor value can be measured at a given frequency.

[0418] The control unit 1180 stores the quality factor value measured at a specific frequency in a predetermined recording area. As an example, the specific frequency may be a predefined frequency within the operating frequency band (S2112). For the sake of convenience, this will be used interchangeably with the measurement start frequency. In addition, the quality factor value measured at the measurement start frequency is named the start quality factor value. .

[0419] The control unit 1180 determines the current peak frequency at which the maximum value of the measured quality factor values ​​is measured. The current peak frequency and the peak quality factor value measured at that frequency are recorded in a predetermined manner. The information can be stored in the area (S2113).

[0420] Here, the frequency at which the quality factor value is measured for the current peak frequency search within the operating frequency band is The frequency offset (or number of frequencies) for determining the wave number will vary depending on the design of the art. Also, the operating frequency band is the same as the corresponding wireless charging This may vary depending on the system design and the applicable standards.

[0421] The wireless power transmitter is measured at a specific frequency (start frequency) and the current peak frequency. A quality factor slope can be calculated based on the quality factor value (S2114). Q_slope' can be determined as follows:

[0422] Q_slope'=(Qc'-Q_start') / (F_current_peak -F_start)

[0423] where F_current_peak is the current peak frequency, and F_start is the specified Frequency (start frequency), Qc' is the peak quality factor value, Q_start' is the start quality factor value It is.

[0424] The wireless power transmitting apparatus compares the calculated quality factor slope with a predetermined quality factor slope threshold value. Then, it can be determined whether a foreign substance is present in the charging area (S2115).

[0425] In yet another embodiment, the predetermined quality factor slope critical value is set to the value of the foreign matter as in the embodiment of FIG. This may be a value that is determined based on information contained in the detection status packet.

[0426] For example, the foreign substance detection status packet may include a quality factor slope critical value or a quality factor slope critical value. A field can be defined to convey information about the corresponding angle unit value. do.

[0427] If a foreign object is detected, the wireless power transmitting device stops transmitting the power signal and It is possible to control the output of a predetermined warning alarm to indicate that a quality problem has been detected. (S2116 and S2117).

[0428] If it is determined in step 2115 that no foreign object is present, the wireless power transmitting device The transmission step can be entered and charging of the corresponding wireless power receiver can be started (S211 6 and S2118).

[0429] In the above examples of FIGS. 19 to 21a and 21b, the start frequency and the current peak frequency The slope of the quality factor is calculated based on the output voltage level measured at However, this is only one embodiment, and other embodiments of the present invention may use the start frequency and the current peak frequency. It is also possible to calculate the quality factor slope based on the quality factor values ​​measured in wavenumber. 19, instead of the output voltage measurement unit 1920 shown in FIG. A quality factor measuring unit (not shown) for measuring the corresponding quality factor value is provided in the foreign substance detection device 1900. It should be noted that it can also consist of

[0430] The method according to the above-mentioned embodiment is implemented as a program for execution by a computer. The present invention can be stored in a computer-readable recording medium. Examples of the computer-readable recording medium include These include ROM, RAM, CD-ROM, magnetic tape, floppy disk, and optical data. Includes storage devices, etc.

[0431] The computer-readable recording medium is a computer system connected via a network. and the computer readable code can be stored and executed in a distributed manner. And a functional program for implementing the above-mentioned method, The code and the code segments are easily instructed by a programmer skilled in the art to which the embodiments pertain. It is arguable.

[0432] The present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It will be apparent to one skilled in the art that such a method can be used.

[0433] Therefore, the above detailed description should not be construed as limiting in all respects but as illustrative and The scope of the present invention is determined by the reasonable interpretation of the appended claims. The present invention includes all modifications within the scope of the present invention. do. [Industrial Applicability]

[0434] According to an embodiment, a method for detecting a foreign object includes: The present invention is applicable to a wireless charging system that detects a foreign object located between the

Claims

1. receiving a first foreign matter status packet and a second foreign matter status packet from the wireless power receiver; and transmitting a foreign object detection indicator indicating the presence of a foreign object in a charging area of ​​the wireless power transmitter to the wireless power receiver; the first foreign substance status packet includes a first reference value and mode information; the second foreign matter status packet includes a second reference value and mode information; the first foreign matter state packet includes one of a reference quality factor and a reference peak frequency; The first reference value indicates information corresponding to a reference quality factor of the wireless power receiver or information corresponding to a reference peak frequency according to the mode information of the first foreign substance state packet, the second foreign matter status packet includes another one of a reference quality factor and a reference peak frequency; A wireless power transmission method, wherein the second reference value indicates information corresponding to the reference quality factor of the wireless power receiver or information corresponding to the reference peak frequency depending on the mode information of the second foreign substance state packet.

2. The method of claim 1 , further comprising: aborting a wireless charging procedure when the foreign object detection indicator indicates the presence of the foreign object in the charging area.

3. The wireless power transmission method of claim 1, wherein, in the receiving step, the first foreign matter state packet is received first and then the second foreign matter state packet is received, or the second foreign matter state packet is received first and then the first foreign matter state packet is received.

4. The method of claim 1 , further comprising receiving a response signal to the foreign substance detection indicator from the wireless power receiver.

5. The method of claim 1 , wherein the foreign substance detection indicator is generated based on the first foreign substance status packet and the second foreign substance status packet.

6. The wireless power transmission method of claim 1 , wherein when the foreign matter exists in the charging area, a peak frequency of the power signal transmitted from the wireless power transmitter is shifted from the reference peak frequency.

7. The wireless power transmission method of claim 1 , wherein the foreign substance detection indicator includes a first foreign substance detection indicator generated based on the first foreign substance status packet and a second foreign substance detection indicator generated based on the second foreign substance status packet.

8. the first foreign substance detection indicator is determined using a measurement quality factor value of a power signal transmitted from the wireless power transmitter and the first reference value; The method of claim 7 , wherein the second foreign substance detection indicator is determined using a measured peak frequency value of a power signal transmitted from the wireless power transmitter and the second reference value.

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