Foreign substance detection method, device and system therefor

Abstract

To provide a foreign substance detection method for more effectively and accurately detecting a foreign substance, and a device and a system for the same.SOLUTION: A state transition process for detecting a foreign substance in a foreign substance detection device includes the steps of: measuring a quality factor value corresponding to a reference operation frequency when sensing an object; retrieving a current peak frequency with a maximum quality factor value in an operation frequency band; receiving a foreign substance detection state packet including information on a reference peak frequency from a wireless power receiver, and acquiring a reference quality factor value and a reference peak frequency value; correcting the measured quality factor value using a differential value between the current peak frequency and the reference peak frequency; and comparing the corrected quality factor value with a predetermined quality factor critical value, and determining presence / absence of the foreign substance.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. The present invention relates to a method for detecting foreign substances, and an apparatus and system for the same. [Background technology]

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

[0003] In order to connect information and communication devices anytime and anywhere, all facilities in society must be equipped with communication functions. The sensor must be equipped with a computer chip that can read the data. Therefore, 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 With the rapid increase in the number of types of portable devices, the task of charging batteries is becoming increasingly time-consuming for users. Wireless power transmission technology is the best way to solve this problem. It has recently attracted interest.

[0004] Wireless power transmission technology (WPT) Wireless energy transfer (WET) is a technology that uses the principle of magnetic field induction to transmit 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 this principle began to be used. Methods of transmitting electrical energy by emitting electromagnetic waves such as lasers have also been attempted. The electric toothbrushes and some wireless razors we use often are actually charged by the electromagnetic induction principle. I'm being charged.

[0005] To date, wireless energy transmission methods have been broadly divided into magnetic induction and magnetic resonance (El using the Electromagnetic Resonance (EMR) method and short wavelength radio frequency It 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 of magnetic fields, and has been quickly commercialized, especially 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 deal with it.

[0007] The magnetic resonance method uses an electric field or a magnetic field 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 within a limited distance and space. However, it has the disadvantage of having a slightly low energy transfer efficiency.

[0008] Short-wavelength wireless power transmission, or simply RF transmission, is a method in which energy is transmitted by radio waves (Ra It takes advantage of the fact that it can be directly transmitted and received in the form of radio wave. This technology is an RF wireless power transmission method that uses a rectenna. Rectenna is a compound word of antenna and rectifier. , refers to an element that converts RF power directly into DC power. In other words, the RF method is an AC radio This technology converts waves into DC and uses them. As efficiency has improved recently, research is being conducted on commercialization. Research is actively underway.

[0009] Wireless power transmission technology is not only used in mobile devices, but also in a wide range of industries, including IT, railways, and home appliances. It can be 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 Object (FO). When a target object is present, the electromagnetic signal emitted from the wireless power transmitter is induced in the FO. For example, FO can be used to heat copper coins, paperclips, pins, balls, etc. This may include a pen, etc.

[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 will the power supply drop sharply, but the temperature rise around the FO will also cause the wireless power receiver and transmitter to malfunction. If the FO located in the charging area is not removed, This not only results in power waste but also causes 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 wireless charging technology field. 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 for wireless charging, and a device and system for the method. do.

[0014] Another object of the present invention is to provide a method for detecting a difference in the frequency of a current peak relative to 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 apparatus for detecting foreign substances that can be easily detected.

[0015] It is yet another object of the present invention to provide a method for measuring 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 calculated slope is compared with a predetermined quality factor slope critical value. By comparing with the above, a foreign substance detection method capable of detecting foreign substances more accurately and The present invention provides an apparatus and system for

[0016] It is yet another object of the present invention to provide a method for measuring the start frequency and the current peak frequency within the operating frequency band. The quality factor slope is calculated based on the obtained quality factor value and compared with a predetermined quality factor slope critical value. A foreign substance detection method and a method for detecting foreign substances that can detect foreign substances more accurately by comparing 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 factors and a method for detecting foreign substances based on peak frequencies. By adaptively applying the foreign substance detection method, it is possible to improve the foreign substance detection capability. 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 aims to provide 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 can be understood from the following description by those skilled in the art. 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 within the operating frequency band. The step of searching for the current peak frequency with the maximum value and the step of searching for the reference peak frequency receiving a foreign substance detection status packet 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:

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

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

[0024] In addition, the foreign object detection method may further include a method for detecting a foreign object, wherein the detected object is a receiver capable of wireless power transmission. and the quality factor value is determined based on the identification after sensing the object. Measurements can be taken with power transmission temporarily interrupted before proceeding to the next stage.

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

[0026] The foreign substance detection method further includes, after the power transmission is interrupted, detecting that a foreign substance has been detected. The step of outputting a predetermined warning alarm indicative of the problem may further be included.

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

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

[0029] Further, the foreign substance detection method includes: 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 wavenumber. and correcting the measured quality factor value using the quality factor transfer value. can.

[0030] In addition, the first maximum quality factor value is received by being included in the foreign substance detection status packet. It is possible.

[0031] The step of determining whether or not the foreign substance exists is performed by determining whether or not the corrected quality factor value is the quality factor. determining that a foreign substance exists if the factor is smaller than the critical value; If the value is greater than or equal to the critical value of the quality factor, it is determined that no foreign substance 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 the start frequency of the operating frequency band and the current peak frequency; calculating a quality factor slope based on the measured output voltage level; and determining whether or not a foreign substance exists based on the obtained quality factor slope. .

[0033] Here, the quality factor slope is the ratio of the output voltage level corresponding to the current peak frequency to 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 substance exists may further comprise determining whether or not the calculated quality factor slope is greater than a predetermined value. 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 exists; and if the determination result is that the foreign substance is larger than or equal to the value of the foreign substance, determining whether or not a foreign substance exists. and determining whether or not the

[0035] According to another embodiment of the present invention, a method for detecting a foreign object in a wireless power transmitter includes: If the quality factor is found, searching for a current peak frequency having the maximum quality factor value within the 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 obtained quality factor gradient.

[0036] Here, the quality factor slope is the ratio of the quality factor value corresponding to the current peak frequency to 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 substance detection device for detecting foreign substances 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; a search unit for searching for a current peak frequency having the maximum quality factor value within the operating frequency band; Receive a foreign object detection status packet containing information about the power frequency from the wireless power receiver. a communication unit for measuring the frequency of the current peak and the reference peak 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 that compares the threshold value 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, and the quality factor reference A threshold value is determined based on the reference quality factor value, and the reference quality factor value is the threshold value of the wireless power reception. The quality factor value measured in response to the reference operating frequency when the power supply of the device is turned off is could be.

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

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

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

[0042] The foreign substance detection device may also detect that a foreign substance has been detected after the power transmission has been interrupted. The device may further include an alarm unit that outputs a predetermined warning alarm indicating the above.

[0043] The foreign substance detection device also confirms whether the detected foreign substance has been removed from the charging area. and a control unit for confirming that the detected foreign substance has been removed. The control unit restarts power transmission to the wireless power receiver, and the warning alarm is released. It can be controlled as follows.

[0044] The foreign substance detection status packet further includes mode information, and 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 communication unit. When the current peak power is received from the wireless power receiver via the a second maximum quality factor value corresponding to the frequency of the quality factor shift value is calculated by subtracting the second maximum quality factor value corresponding to the frequency of the 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] If the corrected quality factor value is smaller than the quality factor critical value, the detection unit , 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, it can be determined that no foreign substance is present.

[0048] A foreign substance detection device for detecting foreign substances 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 within the operating frequency band. a peak frequency search unit for searching the 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 determination unit that calculates 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 substance detection device for detecting foreign substances 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 within the operating frequency band. a peak frequency search unit for searching the start frequency of the operating frequency band and the current peak frequency; a quality factor measurement unit for measuring a quality factor value at a wave number; and a quality factor slope determination unit that calculates a quality factor slope; The apparatus may include a foreign substance detection unit that determines 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 adaptively adjusted depending on whether or not foreign matter is detected by each method, improving the foreign matter detection capability. It is therefore possible to provide a method for detecting foreign substances, and an apparatus and system for the method. can.

[0051] Furthermore, the present invention provides a method for detecting a difference 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, and a device and system therefor, capable of detecting foreign substances. It is possible.

[0052] Yet another 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 on which the above program is recorded.

[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 are not necessarily the same. The various embodiments depicted are described in detail below by a person skilled in the art. These and other objects, features, and advantages of the present invention will become more apparent from the following detailed description of the invention. [Effects 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 provides a method for detecting foreign substances that can detect foreign substances more accurately, and It would be advantageous to provide an apparatus and system for:

[0057] In addition, the present invention can minimize unnecessary power consumption and heat generation caused by foreign materials. 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 advantageous to provide a method and apparatus for detecting foreign substances that can do this.

[0059] The present invention also provides an output voltage measured at the start frequency and the current peak frequency within the operating frequency band. Calculating a quality factor slope based on the pressure level and comparing it to a predetermined quality factor slope critical value. By doing so, it is possible to more accurately detect foreign substances, and a foreign substance detection method and device therefor are provided. The advantage of this is that it provides a system that

[0060] Another object of the present invention is 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 measured quality factor value, and the calculated slope is used as a predetermined quality factor slope critical value. A foreign substance detection method and its method for detecting foreign substances more accurately by comparing the measured value with the actual value. It would be advantageous to provide an apparatus and system for

[0061] 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. A foreign substance detection method that can improve foreign substance detection capabilities 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 substances based on the direction of movement of peak frequencies. 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 be clearly understood by those skilled in the art to which the present invention pertains. Deaf. [Brief explanation 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] [Figure 2] FIG. 10 is a block diagram illustrating a wireless charging system according to another embodiment of the present invention.

[0066] [Figure 3] 1 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 illustrating the structure of a wireless power receiver that operates in conjunction with the wireless power transmitter shown in FIG. 6.

[0072] [Figure 8] 1 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 illustrating packet types according to an embodiment of the present invention.

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

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

[0077] [Figure 12] FIG. 10 is a block diagram illustrating the structure of a foreign substance detection device according to another embodiment of the present invention.

[0078] [Figure 13a] 4A and 4B are diagrams illustrating a state transition process for detecting foreign matter in a foreign matter detection device according to an embodiment of the present invention.

[0079] [Figure 13b] 4A and 4B are diagrams illustrating a state transition process for detecting foreign matter in a foreign matter detection device according to an embodiment of the present invention.

[0080] [Figure 13c] 4A and 4B are diagrams illustrating a state transition process for detecting foreign matter in a foreign matter detection device according to an embodiment of the present invention.

[0081] [Figure 13d] 4A and 4B are diagrams illustrating a state transition process for detecting foreign matter in a foreign matter detection device according to an embodiment of the present invention.

[0082] [Figure 14a] 10 is a diagram illustrating the message structure of an FOD status packet according to one embodiment of the present invention.

[0083] [Figure 14b] 10 is a diagram illustrating the message structure of an FOD status packet according to one embodiment of the present invention.

[0084] [Figure 15] 10 is a diagram illustrating a message structure of an FOD status packet according to another embodiment of the present invention.

[0085] [Figure 16] 1 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] 10 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] 10 is a graph showing experimental results illustrating changes in quality factor values ​​and peak frequencies depending on the placement of foreign materials in a wireless charging system according to the present invention.

[0088] [Figure 19] FIG. 10 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]10 is a diagram illustrating a change in the slope of a quality factor depending on whether or not a foreign substance is present in a wireless charging system according to the present invention.

[0090] [Figure 21a] 10 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] 10 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 INVENTION

[0091] In one embodiment of the method for detecting a foreign object in a wireless power transmitter, when an object is detected, a reference motion is performed. measuring a quality factor value corresponding to an operating frequency; and determining whether the quality factor value within the operating frequency band is the maximum. and a step of searching for a current peak frequency that includes information about the reference peak frequency. 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 THE INVENTION

[0092] Hereinafter, the apparatus and various methods to which the embodiments of the present invention are applied will be described in more detail with reference to the drawings. The suffixes "module" and "section" for components used in the following description are for clarity. They are assigned or mixed in consideration of the ease of creating specifications, and are not distinguishable from each other as such. It does not have the meaning or role that is specified in the regulations.

[0093] In the description of the embodiments, when it is described as being formed "above or below" each component, In this case, the upper or lower means that 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 arranged between two components. When used 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 is 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, a wireless power receiving device will be used in combination with a wireless power transmitter. For convenience of explanation, the term "wireless power receiving device" is used to refer to a device equipped with the function. Wireless power receiver, wireless power receiving device, wireless power receiver, receiving terminal, receiving side, receiving device It can be used in combination with other devices, receivers, etc.

[0095] The transmitter according to the present invention may be in the form of a pad, a fixed 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 also transmit power to multiple wireless power receiving devices. To this end, the transmitter may also comprise at least one wireless power transmission means, where: The wireless power transmission means generates a magnetic field in the power transmitting end coil, and receives the influence of the magnetic field. It is based on the electromagnetic induction method, which uses the principle of electromagnetic induction to charge the battery, where electricity is induced in the input coil. Various wireless power transmission standards can be used. WPC (Wireless Power Consortium), the standard organization for wireless charging technology m) and electromagnetic as defined by the PMA (Power Matters Alliance) 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 Organization) 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 mobile phones, smartphones, smartphone, laptop computer , digital broadcasting terminals, PDAs (Personal Digital Assistants) nts), PMP (Portable Multimedia Player), navigation game smartphones, MP3 players, electric toothbrushes, electronic tags, lighting devices, remote controls Used for small electronic devices such as radar, floats, and wearable devices like smartwatches. However, the present invention is not limited to this. Any device that can charge a battery is sufficient.

[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 generally includes a wireless power transmitting terminal that transmits power wirelessly. 10, a wireless power receiving terminal 20 for receiving the transmitted power, and a receiving terminal 21 for receiving the received power. The electronic device 30 may include:

[0100] For example, the wireless power transmitting end 10 and the wireless power receiving end 20 are used for wireless power transmission. In-band communication is performed 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. 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 for wireless power transmission. Out-of-band (OUTB) communication is a method of exchanging information using a separate frequency band different from the operating frequency. d) Communication can also be carried out.

[0103] For example, information exchanged between the wireless power transmitting end 10 and the wireless power receiving end 20 is The information exchanged between the transmitting and receiving ends can include not only status information but also control information. The status information and control information will become more apparent from the description of the embodiment below.

[0104] The in-band and out-of-band communications may provide two-way communication, but are not limited to this. Alternatively, other embodiments may provide for simplex or half-duplex communication. 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, and the wireless power transmitting end 10 may be a wireless power receiving end 20. It may also transmit information to

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

[0107] The wireless power receiving end 20 according to an embodiment of the present invention acquires various status information of the electronic device 30. For 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 - The output voltage / current information may include, but is not limited to, the output voltage / current information from the electronic device 30 Any information that can be obtained and 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 packet can be transmitted to the wireless power receiving end 20. The wireless power receiving end 20 If it is confirmed that the wireless power transmitting terminal 10 supports the fast charging mode, This can be notified to the electronic device 30. The electronic device 30 has a predetermined display means, The indication that fast charging is possible is displayed via a display means, which may be, for example, a liquid crystal display. 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 transmitting end 10 can 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 fast charging request signal may be transmitted to the wireless power receiving terminal 20. The wireless power receiving terminal 20 The wireless power transmitting end 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 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 terminal 20 may include a plurality of wireless power A plurality of wireless power receiving devices can be connected to one wireless power transmitting end 10. Here, the wireless power transmitting terminal 10 can be connected to multiple devices in a time-division manner to perform wireless charging. However, the present invention is not limited to this. For example, the wireless power transmitting end 10 may receive 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 requirements for each receiving device, battery charge status, power consumption of electronic devices, and wireless power transmission devices The power consumption may 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 configured as a plurality of wireless power transmitting devices. and can simultaneously receive power from the connected wireless power transmitting devices. Here, the wireless power receiving terminal 20 can receive the wireless power and charge the battery. 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 consumption 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 transmitting device, etc. .

[0114] In addition, a plurality of wireless power transmitting devices may transmit power to a plurality of 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. Predetermined sensing signals 117, 127, e.g., digital ping signals, are sent in a predefined order. Next, send it.

[0117] As shown in FIG. 3, the wireless power transmitter includes a first sensing signal transmission path indicated by reference numeral 110. The sensing signal 117 is sequentially transmitted through the process, and the wireless power receiver 115 outputs a signal strength indicator (S Transmitting coil 1 where the signal strength indicator (SISI) 116 was received 11, 112. Next, the wireless power transmitter is shown in the drawing number 120. 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 that has a good alignment between the transmitting coil and the receiving coil, and 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 is.

[0119] As shown in FIG. 3, the first transmitting coil 111 and the second transmitting coil 120 are If the signal strength indicator 116, 126 is received at the transmit 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 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, the power transfer from the transmitter to the receiver is roughly divided into a selection stage. ction Phase 410, Ping Phase 420, Identification and Identification and Configuration Phase Hase 430 and Power Transfer Phase 26 It can be divided into 0.

[0122] A selection step 410 is performed to determine whether a particular error or This can be a transition stage when a specific event is detected. Certain events will become clearer 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 detects this, it can transition to the ping step 420 (S401).

[0124] In selection step 410, the transmitter sends out a very short pulse of analog ping (Analog Ping). ng) signal can be transmitted and the charging interface can be There is an object in the active area of ​​the surface, i.e., the area that can be charged. It can sense whether

[0125] In the ping step 420, if the transmitter senses an object, it activates the receiver, i.e., and a digital booting to identify 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, may be received from the receiver. If not, 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 selection step 410 (S403).

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

[0127] In the identification and configuration step 430, the transmitter determines whether unwanted packets are received (unexpected packets). received packet), when the desired packet is not received within a predefined period of time. (time out) or packet transmission error (transmission error) rror), if no power transfer contract is configured (no power transfer contract), a transition to selection step 410 can be made (S405).

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

[0129] In the power transmission step 440, the transmitter determines whether an unwanted packet is received (unexpected packet). ted packet), or the desired packet is not received for a predefined period of time ( time out), whether a violation of the established power transmission contract occurs (power transfer contract violation), if charging is complete, 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 is set based on the status and characteristics information of the transmitter and receiver. For example, the transmitter status information may 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 for explaining the wireless power transmission process.

[0133] Referring to FIG. 5a, power transfer from a transmitter to a receiver according to one embodiment of the present invention is Separately, 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 It can be divided into two phases:

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

[0135] If an object is sensed in the selection step 510, the wireless power transmitter will , 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, the charging area is detected as a foreign substance. The quality factor can be measured to determine whether a wireless power receiver is placed in the same location. The coil provided in the line power transmitter changes in inductance and / or coil resistance depending on the environmental changes. The series resistance component in the capacitor can be reduced, which results in a reduced quality factor value. The wireless power transmitter determines whether or not a foreign substance is present using the measured quality factor value. The reference quality factor value measured in advance when no foreign matter 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. For low-value wireless power receivers, for example, the type, use and characteristics of the wireless power receiver For a particular wireless power receiver with a low reference quality factor value due to the presence of foreign matter, If there is no significant difference between the measured quality factor value and the reference quality factor value, it is difficult to determine whether or not foreign matter is present. 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, an abnormality is detected in the charging area. To determine whether a wireless power receiver is placed with a substance, For example, the quality factor value can be measured in the operating frequency range. The change in the temperature can reduce the inductance and / or the series resistance in the coil. , which can change (shift) the resonant frequency of the coil of the wireless power transmitter. That is, the quality factor peak is the frequency at which the maximum quality factor value within the operating frequency band is measured. The peak frequency can shift.

[0138] For example, a wireless power receiver includes a magnetic shield (shielding material) with high magnetic permeability. Therefore, high permeability increases the inductance value measured in the coil of a wireless power transmitter. On the other hand, metallic foreign substances decrease 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 resulting graph is shown in Figure 5b.

[0140] Referring to Figure 5b, in general, for an LC resonant circuit, the resonant frequency (f_resonant t) is Calculated by TIFF0007779879000001.tif7169.

[0141] Referring to the left graph of Figure 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 substance is placed in the charging area, the L value decreases. This reduces the resonance frequency, which increases and shifts it to the right on the frequency axis. become.

[0143] The frequency with the largest measured quality factor, i.e., the measured peak frequency, is used to identify foreign substances. To determine the presence of foreign matter, the wireless power transmitter must ensure that 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 measured The presence or absence of foreign matter can be determined by comparing the determined peak frequency values.

[0144] The method of detecting foreign substances by comparing peak frequencies is used in conjunction with the method of comparing quality factor values. If there is no significant difference between the reference quality factor value and the measured quality factor value, If the difference is less than 10%, for example, 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 substance is present.

[0145] In yet another embodiment, the 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 whether there is any foreign substance. If it is difficult to detect foreign matter using quality factors, the presence or absence of the foreign matter can be determined by wireless power. The receiver includes information about the reference peak frequency in the foreign substance detection status packet and transmits the radio power 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 senses an object, it wakes up the receiver. ) and a digital ping (D) to identify whether the detected object is a wireless power receiver. In a ping step 520, the transmitter transmits a digital ping. If a response signal, such as a signal strength packet, is not received from the receiver, , and can transition back to selection step 510. Also, in ping step 520, the transmitter Receives a signal indicating that power transfer is complete from the receiver, i.e., a charging completion packet. If so, the process may proceed to selection step 510.

[0148] Once the ping step 5220 is complete, the transmitter identifies the receiver and returns receiver configuration and status information. The process may proceed to an identification and configuration step 530 to collect the

[0149] In the identification and configuration step 530, the transmitter determines whether unwanted packets are received (unexpected packets). received packet), when the desired packet is not received within a predefined period of time. (time out) or packet transmission error (transmission error) rror), if no power transfer contract is configured (no power transfer A transition to contract selection step 510 can be made.

[0150] The transmitter identifies and configures the received configuration packet (Configura Negotiation Field value in the Response packet Based on this, it can be determined whether it is necessary to proceed to the negotiation stage 540.

[0151] If the result of the check indicates that negotiation is necessary, the transmitter proceeds to negotiation step 540 to determine whether a predetermined FOD detection is necessary. The process can be carried out.

[0152] On the other hand, if the result of the check indicates that negotiation is not necessary, the transmitter immediately proceeds to the power transmission step 560. You can also do this.

[0153] In the negotiation step 540, the transmitter receives a Foreign Object Descriptor (FOD) containing a reference quality factor value. Detection) status packets can be received. A FOD status packet containing a peak frequency value can be received. A status packet containing a quality factor value and a reference peak frequency value can be received. 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 The power transmission can be controlled based on 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 determine the presence of FO in the charging area. It is possible to detect whether the power is being transmitted or not, and power transmission can be controlled based on the results of the FO detection. By way of example, but not limitation, 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 no power is detected, the transmitter goes through a correction stage 550 and enters a power transfer stage 560. In detail, if no FO is detected, the transmitter may correct the received To determine the strength of the power received at the end and the strength of the power transmitted from the transmitting end, The power loss at the receiving end and the transmitting end can be measured, i.e. the transmitter performs a correction step 55 0, predicting power loss based on the difference between the transmit power at the transmitting end and the receive power at the receiving end. In one embodiment, the transmitter may incorporate a predicted power loss into the clinical signal for FOD detection. The threshold value can also be corrected.

[0157] In the power transmission step 560, the transmitter determines whether an unwanted packet is received (unexpected ed packet), or if the desired packet is not received for a predefined time (t time out), or will there be a violation of the power transfer agreement already established (power r transfer contract violation) If charging is completed, A transition can be made to 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 agreement needs to be restructured, a transition to a renegotiation stage 570 can occur. If the renegotiation is successfully completed, the transmitter may revert to the power transfer stage 560 .

[0159] The power transfer agreement is set based on the status and characteristics information of the transmitter and receiver. For example, the transmitter status information may 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, a power transmission unit 612, and a power converter 614. 620, a communication unit 630, a control unit 640, and a sensing unit 650. The above-described 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 the power supply unit 660, the power conversion unit 610 , and converts it into AC power of a predetermined intensity.

[0163] For this purpose, the power conversion unit 610 includes a DC / DC conversion unit 611, an inverter 612, and The inverter 612 may comprise a half-bridge frequency generator 613. 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 with a specific operating frequency, That's enough.

[0164] The DC / DC converter 611 controls the DC power control unit 640 supplied from the power supply unit 650. It can perform the function of converting DC power of a specific strength according to the signal.

[0165] Here, the sensing unit 650 measures and controls the voltage / current of the DC converted power. The sensing unit 650 can provide a signal to the temperature sensor 640 to determine whether overheating has occurred. To achieve this, 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 detect the voltage measured by the sensing unit 650. / Depending on the current value, the power supply from the power supply unit 650 is adaptively cut off or the amplifier (inverter To this end, the power supply to the power converter 612 can be cut off. One side of the power supply unit 610 is either cut off from the power supply unit 650 or cut off from the power supply unit 612. The power supply 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 a The generated reference AC signal can be converted into AC power in accordance with 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. 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) power control signal, and the received power reception status information or ( and) determining an operating frequency in response to a power control signal, and generating the determined operating frequency. The frequency generator 613 can be dynamically controlled as shown below.

[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 about the strength of the current being applied. This may include a signal to request an increase in power, a signal to request a decrease in power, etc.

[0169] The power transmission section 620 includes a multiplexer (or multiflexor) 621 and a transmission coil section 622. Here, the transmitting coil section 622 is composed of first to n-th transmitting coils. Also, the power transmission unit 620 can be configured to receive a specific carrier frequency for power transmission. It may further include a carrier generator (not shown) for generating the number. The transmission wave generator receives the output AC power of the inverter 612 transmitted via 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 transmitting coil are different from each other. Another embodiment of the present invention uses LC resonance characteristics. Each transmit coil is adjusted differently using a predetermined frequency controller. The resonant frequencies of the respective transmitting coils can 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 the received signal for each transmitting coil. and selecting a transmitting coil to be used for power transmission 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 control a plurality of wireless power receivers connected to the same network. 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. If the time slot is determined to be different, 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 allocated to each transmitting coil determines the length of the corresponding wireless power receiving coil. Although the amount of power transmitted to the receiver can be controlled, this is only one example and other examples may be used. The output direct current of the DC / DC converter 611 is supplied during the time slots assigned to each transmitting coil. The strength of the current power can be controlled to control the power transmitted by 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 sequentially. The time when the sensing signal is transmitted can be identified by the timer 655 in the 640. When the transmission time comes, the multiplexer 621 is controlled to transmit the sensing signal through the corresponding transmission coil. For 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 generate 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 transmitting coil is output from the demodulator 632 during the primary sensing signal transmission process. A Signal Strength Indicator is received via A predetermined transmitting coil identifier for identifying whether the signal was received or not and the 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 transmit coil (etc.) where the signal strength indicator is received. The multiplexer 621 can also be controlled.

[0178] As another example, the control unit 640 may receive a signal strength indicator during the primary sensing signal transmission process. If there are multiple transmit coils, the transmit coil from which the signal strength indicator with the greatest value is received is is determined as the transmitting coil that should first transmit the sensing signal in the secondary sensing signal transmission process, and the determination result The multiplexer 621 can also be controlled by

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

[0180] The modulator 631 modulates the control signal generated by the controller 640 and sends it to the multiplexer 621. Here, the modulation method for modulating the control signal is FSK (Freq. Shift Keying). Quasi-Shift Keying modulation, Manchester coding (M Anchor Coding modulation method, PSK (Phase Shift Keying) ying modulation method, Pulse Width Modulation This includes differential bi-phase modulation, etc. It can be, but is not limited to,

[0181] If the signal received through the transmitting 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 This may include, but is not limited to, overvoltage / overcurrent / overheat indicators, etc. Various status information may be included to identify the status of the receiver.

[0182] In addition, the demodulation unit 632 determines from which transmitting 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] The demodulation unit 632 demodulates the signal received via the transmission coil 622 and outputs it to the control unit 6 40. By way of example, the demodulated signal may include a signal strength indicator. The demodulated signal may include, but is not limited to, various status information of the wireless power receiver. This can be done.

[0184] As an example, the wireless power transmitter 600 may be configured to transmit wireless power using the same frequency as that used for wireless power transmission. and transmitting said signal strength indicator via in-band communication with a line power receiver. can be acquired.

[0185] The wireless power transmitter 600 transmits wireless power using the transmission coil unit 622. Not only can it transmit various control signals and receive signals from the wireless power receiver through the transmitting coil unit 622, 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 have to be careful not to do 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 the frequency used for wireless power signal transmission may be different. Short-distance two-way communication can be performed using a frequency band different from the frequency band. Short-range 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 the above description of FIG. 6, the power transmission unit 620 of the wireless power transmitter 600 is the multiplexer 62 Although the present invention includes one or more transmit coils 622, this is merely one embodiment and other embodiments may be used. Note that the force transmission section 620 can also consist of a single transmitting coil. It must be.

[0188] FIG. 7 is a block diagram illustrating the structure of a wireless power receiver that operates in conjunction 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 DC / DC / DC Converter 730, Load 740, Sensing Unit 7 50, a communication unit 760, and a main control unit 770. 0 can 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 signal to a wireless power transmitter via in-band communication. 600, this is only one example. In addition, the communication unit 760 according to another embodiment of the present invention uses a frequency band used for wireless power signal transmission. It can 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 720. The rectifier 720 converts AC power into DC power and transmits it to the DC / DC converter 730. The DC / DC converter 730 adjusts the intensity of the rectifier output DC power depending on the load 740. After being converted to a specific intensity as required, 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. In addition, the sensing unit 750 can provide a receiving controller by wireless power reception. The intensity of the current applied to the coil 710 is measured, and the measurement result is transmitted 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 control unit 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 outputs a detection signal when the rectifier output DC power intensity is equal to or greater than a predetermined reference value. When a sensing signal is received, the corresponding signal is The intensity indicator can be transmitted to the wireless power transmitter 600 via the modulation unit 762. As another example, the demodulator 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 detection signal is received. After the identification, the identification result can be provided to the main control unit 770. 70, a signal strength indicator corresponding to the sensing signal can be transmitted through a modulation unit 762. It can be controlled so that

[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 numeral 810 in FIG. 8, the wireless power transmitting end 10 and the wireless power receiving end 20 are the same. 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 for encoding packets 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 not transmitted, the wireless power signal will have a specific frequency as shown in drawing number 41 in Figure 1. The 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 AC signal modulated by a specific modulation method, as shown in drawing number 42 in Figure 1. 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 phase encoding In detail, differential bi-phase encoding can be applied. The signal undergoes two state 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 set on the rising edge of the clock signal. ing 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 drawing number 830, a byte according to one embodiment is shown. The encoding technique applies to an 8-bit encoded binary bitstream. Start bit to identify the start and end of this bitstream ) and stop bit, corresponding bit stream (byte) error It is a method to insert a parity bit to detect whether or not an error has occurred. It is possible.

[0202] FIG. 9 is a diagram illustrating a packet format according to an embodiment of the present invention.

[0203] Referring to FIG. 9, the wireless power transmitting end 10 and the wireless power receiving end 20 are used for information exchange. The packet format 900 is used for synchronization acquisition for demodulation of 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 If an error occurs in the Message 930 field and the corresponding packet Contains a checksum 940 field to verify that the It can be done in.

[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) of the Ping phase Power Transfer) and header value corresponding to the end of power transfer in the power transfer phase It should be noted 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. It can be a request or a response, This is not limited to this.

[0207] A packet 900 according to another embodiment of the present invention identifies a transmitting end that transmitted the corresponding packet. receiving end identification information for identifying a receiving end that receives the corresponding packet; In this case, at least one of 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. Without being limited thereto, information that can distinguish a receiving end from a transmitting end in a wireless charging system It is sufficient if the information is correct.

[0208] A packet 900 according to yet another embodiment of the present invention is a packet that is sent by multiple devices. If the data must be received by a specific group, a predetermined group identifier must be used to identify the receiving group. It may also contain other information.

[0209] FIG. 10 shows a block diagram of a wireless power receiver according to an embodiment of the present invention. FIG. 2 is a diagram illustrating packet types.

[0210] Referring to FIG. 10, a packet transmitted from a wireless power receiver to a wireless power transmitter is Signal Strength (SSI) is used to transmit the strength information of the received ping signal. h) Packet, power transmission type (End) for requesting that the transmitter stop power transmission Power Transfer), 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 packet, identification packet and extended identification packet for transmitting receiver identification information, general request message General request packets for transmitting special request messages, and special request packets for transmitting special request messages. 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, a renegotiation packet for starting renegotiation, 24-bit received power packet and 8-bit received power packet for transmitting received power strength information The packet includes a power packet and a charging status packet for transmitting charging status information of the current load. 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 can be transmitted using in-band communication using the same frequency band as the signal being transmitted.

[0212] FIG. 11-a shows a foreign substance 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 circuit.

[0213] Referring to FIG. 11-a, a foreign substance detection device (circuit) 1190 includes a power supply unit 1191, a driving unit 1192, resonance capacitor 1193, transmitting coil 1194, quality factor measuring 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 intensity of the AC power can be adjusted according to the control signal of the driving unit 1192. is a frequency oscillator that generates a specific frequency signal and the frequency generated by the frequency oscillator. The power supply may include an inverter for amplifying the AC signal.

[0216] The driving unit 1192 controls the frequency (operating frequency) of the AC signal in response to a control signal from the control unit 1197. At least one of the frequency, 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 demodulator 1196 demodulates the signal received from the wireless power receiver and transmits the demodulated signal to the controller 1197. For 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. In addition, the control unit 1197 can 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 quality factor values ​​measured 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 the quality factor based on the reference quality factor value and the maximum quality factor value included in the FOD status packet. 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 relative 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. Compare the current quality factor value received and / or the operating frequency (critical frequency) received and the measured or calculated operating frequency, e.g., the operating frequency (peak) corresponding to the maximum quality factor value. or the operating frequency at which a quality factor of 5% or less of the reference quality factor value is measured. It is possible to determine whether FO exists 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 a different 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] The quality factor measurement unit 1195 according to an embodiment of the present invention measures the capacitance between both ends of the resonant capacitor 1193. The circuit may include a circuit configuration that measures the voltage and transmits it to the control unit 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 the quality factor value of the transmitting 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 stage can be resumed.

[0226] FIG. 11-b shows a foreign substance detection device (circuit) in a wireless power transmitter according to another embodiment of the present invention. 11A and 11B are diagrams for explaining the structure (an extended embodiment of FIG. 11A).

[0227] Referring to FIG. 11-b, the foreign substance detection device 1100 includes a power supply unit 1101, a DC / DC converter, DC-DC Converter 1110 (optional), Inverter ter) 1120, resonant circuit 1130, measuring unit 1140, communication unit 1160, alarm The present embodiment may include a control unit 1175 (optional) and a control unit 1180. 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 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 1 110.

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

[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 comprise, but is not limited to, a half bridge. ge).

[0233] As another example, the inverter 1120 may be used in both half-bridge and full-bridge configurations. In this case, the control unit 1180 controls the inverter 1120 to Dynamically determines and controls 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 device receives power requested by a wireless power receiving device. The bridge mode of the inverter 1120 can be adaptively controlled according to the strength of the power. Here, the bridge mode includes the half-bridge mode and the full-bridge mode. For example, if 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 transmitting device may be configured to adaptively switch to bridge mode according to the 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 The power supply can be controlled to activate the full-bridge mode, i.e., wireless power transmission. The device uses a full bridge circuit to increase the voltage and achieve resonance for the same power transmission. The intensity of the current flowing through the circuit 1130 is reduced to reduce the internal temperature of the wireless power transmitting device. can be controlled so as to maintain it at or below a predetermined reference value.

[0236] Generally, the amount of heat generated by electronic components installed in electronic devices is determined by the amount of heat applied to the electronic components. It may be more sensitive to the current intensity than the voltage intensity.

[0237] In addition, the inverter 1120 can not only convert DC power to AC power, The strength of the AC power can also be changed.

[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 power signal to adjust the strength of the AC power output. For this purpose, the inverter 1120 generates a reference AC signal having a specific frequency. Although this is only one example, in other examples it may comprise a frequency oscillator. The frequency oscillator is configured separately from the inverter 1120 and is connected to one side of the foreign substance 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. It further includes a gate driver (not shown) for controlling the switch. In this case, the gate driver can be configured as and receiving one pulse-width modulated signal and outputting an output signal in response to the received pulse-width modulated signal. The control unit 1180 can control the switches 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 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 capacitances of the resonant capacitor 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 control unit 1180, which then determines the Storing the quality factor value and peak frequency value transmitted from the measurement unit 1140 in the recording area It is also possible.

[0241] The measurement unit 1140 measures a frequency corresponding to a predetermined reference operating frequency in response to a control signal from the control unit 1180. A quality factor value corresponding to the quality factor, i.e., a reference measurement 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 measures the quality factor values ​​at a plurality of different frequencies within the operating frequency band beforehand. The control unit 1180 can control the maximum value of the measured quality factor. The corresponding frequency can be 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 foreign matter exists based on the information contained 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 contains a reference quality factor value or ( and) Reference Peak Frequency (F_reference_peak) values. It can be enjoyed.

[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. For example, a value corresponding to 90% of the reference quality factor value is used as the quality factor. The quality factor critical value may be determined, but is not limited to this, and may be applied to determining the critical value. The ratio can be defined differently by those skilled in the art.

[0247] The control unit 1180 calculates the current peak frequency (F_current_peak) value and the reference peak frequency (F_current_peak). Reference measurement quality factor value based on the difference between the peak frequency (F_reference_peak) values (Q_measured_reference) can be corrected. For example, The larger the value obtained by subtracting the reference peak frequency value from the current peak frequency value, the The quality factor value can be further increased. For this purpose, the current peak frequency (F_curr The difference between the reference peak frequency (F_reference_peak) and the reference peak frequency (F_reference_peak) A specific correction function that factors the values ​​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 configured and maintained.

[0248] The control unit 1180 compares the corrected reference measurement quality factor value with the determined quality factor critical value. By doing so, it is possible to detect foreign matter placed in the charging area.

[0249] As an example, the control unit 1180 may calculate 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 determines 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 determined 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 value subtracted from the 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. It is possible to detect foreign matter placed in the charging area.

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

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

[0253] Also, if a foreign substance 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, it is compared with the critical value already determined, and the detected foreign substance is filled. It can be determined whether the object has been removed from the electrical field.

[0254] If the foreign matter is removed, the control unit 1180 proceeds 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 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 illustrating the configuration of a foreign substance detection device according to another embodiment of the present invention. 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 1210 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 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 reference 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 risk.

[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 suspended and a search may be made for a frequency within the operating frequency band that has the maximum quality factor value. where 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 highest quality factor value is defined as 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 is the frequency when only the wireless power receiver is placed in the charging area. It can have a large value compared to the acquired reference peak frequency.

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

[0262] The communication unit 1230 receives a foreign object detection status packet (FOD( Foreign Object Detection (Status Packet) Here, the foreign substance detection status packet can be received as follows: The information may include at least one of information about the total quality factor and information about the reference quality factor value. The structure of the quality detection status packet will become clearer with the explanation of FIGS. 14 and 15 below. It would be.

[0263] The determination unit 1240 determines whether the foreign substance is present or not based on the reference quality factor value included in the foreign substance detection status packet. It is possible to determine the critical value of the quality factor to determine whether or not quality exists. The quality factor critical value can be determined as a value 10% smaller than the reference quality factor value. This is only an 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) is calculated based on the difference between the frequencies (F_reference_peak). _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 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_reference_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. 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, the greater the correction amount of the quality factor critical value. can be done.

[0266] Hereinafter, for convenience of explanation, the quality factor critical value corrected by the corrector 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 material in the charging area. For 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 exists 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 substances are present in the

[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 by the transfer step. 0, the operations of the determination unit 1240, the correction unit 1250, the detection unit 1260, etc. can be controlled. Cut.

[0269] Generally, depending on the type of wireless power receiving device, the reference quality factor measured at the reference operating frequency is 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 ​​with the quality factor values ​​may be different.

[0270] Therefore, the foreign substance detection device 1200 sends a foreign substance detection status packet (FOD (Foreign Entity Detection Status Packet) (Sign 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 stage. If the measured quality factor 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 diagram for detecting a foreign substance in a foreign substance detection device according to an embodiment of the present invention. FIG. 10 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 substance detection device 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 substance detection device performs the ping step 132. measuring quality factor values ​​for a plurality of different frequencies within the 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.

[0275] In the ping step 1320, the foreign substance detection device pings the wireless power receiver with a predetermined voltage to identify the wireless power receiver. A force signal, for example a digital ping, may be transmitted periodically.

[0276] The foreign substance detection device has 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 substance detection device performs identification and configuration. The wireless power receiver is identified in step 1330, and the wireless power receiver is identified. Various configuration parameters can be set.

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

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

[0280] In step 1, the foreign substance detection device detects at least one foreign substance from the identified wireless power receiver. A detection status packet can be received. Here, the foreign substance detection status packet is and at least one of information about peak frequency values ​​and information about reference quality factor values. It is possible.

[0281] The information about the reference quality factor value is displayed when the wireless power receiver is turned off. It can refer to the quality factor value measured relative to a reference operating frequency. OFF can mean that no power is being transmitted to the load. The information about the frequency value of the wireless power receiver is stored in the charging area of ​​the wireless power transmitter. This means the frequency with the maximum quality factor value within the operating frequency band when only 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 substance detection device determines whether foreign substances exist based on the received reference quality factor value. A critical value of the quality factor for the judgment can be determined.

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

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

[0285] If the foreign substance is detected, the foreign substance detection device stops the power transmission and selects the foreign substance detection device. Alternatively, an indicator indicating the presence of foreign matter can be wirelessly transmitted. 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 there is no foreign substance, the process can proceed to the next stage. If not, the foreign substance detection device proceeds to power transmission step 1350 to transmit power to the corresponding wireless power receiver. Wireless charging can then be initiated.

[0286] FIG. 13b shows a state for detecting foreign matter in a foreign matter detection device according to another embodiment of the present invention. FIG. 10 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 substance detection device 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 substance detection device performs a ping step 132. Measure quality factor values ​​for a plurality of different frequencies within the operating frequency band before entering 1; 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.

[0289] In the ping step 1321, the foreign substance 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 substance detection device stores information about the measurement quality factor value and the current peak frequency value in a predetermined storage location. It can be stored in the recording area.

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

[0292] Once the identification and configuration of the wireless power receiver is completed, the foreign substance detection device proceeds to 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 step 1, the foreign substance detection device detects at least one foreign substance from the identified wireless power receiver. A detection status packet can be received. Here, the foreign substance detection status packet is and at least one of information about peak frequency values ​​and information about reference quality factor values. It is possible.

[0295] The information about the reference quality factor value is displayed when the wireless power receiver is turned off. It can refer to the quality factor value measured relative to a reference operating frequency. OFF can mean that no power is being transmitted to the load. The information about the frequency value of the wireless power receiver is stored in the charging area of ​​the wireless power transmitter. This means the frequency that has the largest quality factor value within the operating frequency band when the frequency is only deployed. The wireless power receiver stores the reference peak frequency value in advance, and This can be transmitted to the wireless power transmitter.

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

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

[0298] If it is determined that a foreign substance is present, the foreign substance detection device according to an embodiment stops power transmission. , the process may return to selection step 1310. A predetermined foreign matter detection indicator indicating the presence of the foreign matter may be transmitted to the wireless power receiver. Here, if the foreign substance detection indicator is received, the wireless power receiver 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 determination is that no foreign matter is present, the foreign matter detection device sets the reference peak frequency value You can determine whether it has been received.

[0300] The foreign substance detection device according to an embodiment of the present invention 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 Based on this, the peak frequency threshold can be determined.

[0303] In step 4, the foreign substance detector compares the peak frequency threshold value with the current peak frequency value to detect foreign substances. 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 value is greater than the threshold, it is determined that a foreign substance is present, and the foreign substance detection device interrupts power transmission and enters the selection stage. 1311. Or, you can use an indicator to indicate the presence of a foreign substance. 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 present, the foreign substance detection device proceeds to power transmission step 1351 to transmit the corresponding wireless power receiver. wireless charging can be initiated.

[0304] In yet another embodiment, in the embodiment of FIG. 13b, the foreign material detection device performs a quality factor value based Before performing the foreign object detection process, check whether the reference peak frequency value has been received from the wireless power receiver. The process of acknowledging the identity of the person can also 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 peak frequency was performed. It is possible to determine whether or not the

[0306] On the other hand, if the reference peak frequency value is not received as a result of the check, the foreign substance 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] When the foreign substance detection process is performed discriminatory depending on whether or not the reference peak frequency is received, This has the advantage that the foreign substance detection process can be carried out in the way that the radio receiver prefers. A foreign substance detection method optimized for the device equipped with the power receiver can be preset during the manufacturing stage. This can be expected to improve the accuracy of detecting foreign substances. Of course, the foreign substance detection method corresponding to the wireless power receiver can be set by the predetermined menu. Note that whether or not the reference peak frequency information is transmitted 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 foreign substance detection method that is optimized for the identified type 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 foreign substance detection process according to another embodiment of the present invention. .

[0309] The wireless power transmitter measures the quality factor value of the co-current 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 be expressed as the amplification ratio of the input and output voltages by the resonant capacitor when Please refer to the explanation of Figure 11-a and Figure 11-b. Here, the operation of the wireless power transmitter The quality factor value for each frequency can be measured within the operating frequency range.

[0310] The wireless power transmitter measures the quality factor and determines the current quality factor value and peak frequency (measured The frequency at which the maximum quality factor value is 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 description 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 substance exists using the quality factor threshold value and the measured quality factor value. You can decide whether or not to have it.

[0314] For example, if the current quality factor value is greater than or equal to the critical quality factor value, the wireless power transmitter It can be determined that a substance exists. If the current quality factor value is smaller than the 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 contain information about the reference peak frequency, If so, the wireless power transmitter can determine that no foreign matter is present. Next steps for transmission (e.g., calibration or power transformer) fer) can be advanced.

[0316] If the information about the reference peak frequency is included, the wireless power transmitter may It is possible to 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 greater than or equal to the peak frequency critical value, it can be determined that foreign matter 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 or absence 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 process of determining whether or not there is a foreign substance based on the quality factor value and the peak circumference The procedure for determining whether or not foreign matter exists based on the wave number can be changed. That is, the presence or absence of foreign matter is determined based on the peak frequency, and then the presence or absence of foreign matter is determined based on the quality factor value. By further advancing the judgment of whether or not foreign substances exist, the ability to detect foreign substances can be improved. Cut.

[0319] FIG. 13d is a diagram illustrating a foreign substance detection process 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 turns on the resonant circuit. The quality factor of a coaxial 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 explanations of Figures 11-a and 11-b. Therefore, it is possible to measure the quality factor value for each frequency 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 substance detection status packet.

[0323] Here, the foreign substance detection status packet is the 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 substance is present 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 measured at a 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 determining a measured quality factor value corresponding to the identified frequency. can be read from memory.

[0326] The frequency at which the quality factor value changes most significantly 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 performs a Here, the presence or absence of foreign matter can be determined. 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 can 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 error range), can be determined to exist.

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

[0330] Referring to Figure 14-a, the FOD status packet message 1400 has a length of 2 bytes. 1401 field, which is 6 bits long, and Mode 1402 field and a 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 Measured and determined in the 1403 field with the power of the wireless power receiver 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 charger corresponding to the charging area. The frequency with the maximum quality factor value within the operating frequency band when only the output 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 reference quality factor value 1403. The reference quality factor value determined by measuring when the wireless power receiver 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 a value from 0 to 63. If the operating frequency band is 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, which is the operating frequency bandwidth divided 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 can be 87KHz to 150KHz. Here, the first data 1401 contains a frequency between 87 KHz and 150 KHz. You can also specify a value.

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

[0335] Referring to Figure 14-b, the FOD status packet message 1410 has a length of 2 bytes. The first data 1411 field may be 6 bits long, and the second data 1411 field may be 2 bits long. Mode 1412 field and 1-byte length 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 is the frequency with the maximum quality factor value within 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 substance 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 measured and determined in the first step can 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 decision can be made based on the

[0337] As shown in FIG. 14-b, the first data 1411 can 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 means that the reference peak frequency is 260KHz. The resolution of the pulse frequency value is 160K, which is the operating frequency bandwidth divided by the number of first data 1411. It can be determined that Hz / 63=2.54KHz.

[0338] Alternatively, the operating frequency band for quality factor measurement can 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 packets of FIGS. 14-a and 14-b are information about the reference peak frequency corresponding to the frequency at which the maximum quality factor value in the number is measured and and information about the 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 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 measured in advance using a transmitter. Here, a specific wireless power transmitter is a standard transmitter. It is a transmitter used for authentication 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 difference in characteristics.

[0340] When the wireless power transmitter receives the FOD status packet shown in FIG. 14, it sets the reference quality factor value and pin The quality factor values ​​measured in the step 520 (or before the step 520) are compared to determine whether or not foreign matter exists. (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 frequency measured in the previous stage (before the ping stage). This is possible (Method 2, example shown 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) are determined based on the received reference quality factor value. hold1 and threshold2 (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 device can determine that a foreign substance is present.

[0344] If the quality factor value measured before the ping step 520 is less than the critical value 1 and greater than the critical value 2, If the values ​​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 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. Reserved 1501 field, 6 bits long, 2 bits Length Mode 1502 field and 1-byte length reference 1503 field, where the reserved 15 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 value when the wireless power receiver is turned off. Information corresponding to the reference quality factor values ​​measured and determined in can 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 to have only the corresponding wireless power receiver placed in the charging area and the lowest power within the operating frequency band. Reference Peak Frequency (RPF) means the frequency with the highest quality factor. Information corresponding to the frequency value (ak Frequency Value) can be recorded. Therefore, the reference peak frequency is set to the value when there is no foreign material in the charging area and the wireless Only the power receiver can be searched for.

[0349] In this embodiment, the foreign substance detection device (or wireless power transmission device) communicates with multiple FOs in the negotiation stage. A D-state packet is received, and the reference peak frequency value and the 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 transmitter, i.e., the operating frequency This can be determined based on 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, the operating frequency band A wireless power transmitter whose frequency band is 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 foreign matter 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 senses an object placed in the charging area in the selection step. If the quality factor is known, the quality factor value corresponding to the reference operating frequency is measured before entering the ping stage. At this time, the transmitting coil The voltage should be 0.5Vrms~2Vrms. Here, rms is the root mean square. means (are).

[0355] In addition, the wireless power transmission device has been tested at a number of different frequencies within the operating frequency band. A current peak frequency, which is a frequency having the 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 the number of frequencies (or the number of frequencies) may vary depending on the design of the artisan. No (S1603).

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

[0357] When the current peak frequency search is completed, the wireless power transmitter 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 begins. Once the identification and configuration of the wireless power receiver is complete, the negotiation stage begins. You can 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 whether or not the presence of the substance is present 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 receives the reference peak power (FP) included in the FOD status packet during the negotiation phase. The quality 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. ) can be performed (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 results, it is possible to determine whether or not a foreign substance is present (S1607).

[0362] If the foreign object is detected, the wireless power transmitting device stops transmitting the power signal and It can be controlled to output a predetermined warning alarm indicating that a quality defect has been detected. (S1608 and S1609).

[0363] If it is determined in step 1608 that no foreign matter 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 the various configuration parameters required for force control. It can also be executed in a more

[0364] FIG. 17 shows the reference peak frequency for each receiver type and the relationship between the placement of foreign matter according to an embodiment of the present invention. 10 is a table showing experimental results for explaining changes in peak frequency.

[0365] Referring to FIG. 17, the reference value obtained when only the wireless power receiver is placed in the charging area is The peak frequency 1710 and the quality factor value 1720 measured at the corresponding reference peak frequency are received. Indicates differences depending on the aircraft 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 substance is placed is the same as when only the wireless power receiver is placed. It can be seen that the peak frequency is higher than the peak frequency of 1710.

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

[0368] Also, referring to drawing number 1750, the position of the foreign substance placed in the charging area is The further away the peak frequency decreases, but the quality factor value increases.

[0369] FIG. 18 shows the quality factor values ​​and peak values ​​depending on the arrangement of foreign materials in the wireless charging system according to the present invention. 10 is a graph showing 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 is increased 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 are placed in the charging area. The peak frequency corresponding to the state, i.e., the quality factor value measured at the current peak frequency, is the first The peak frequency corresponding to the receiver alone is measured at the reference peak frequency. This indicates that the quality factor value decreases by ΔQ from the 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] The foreign substance detection device according to an embodiment of the present invention is configured to detect the peak frequency shift value and the quality factor shift value. The reference measurement quality factor value may also be corrected based on the peak frequency shift value The larger the sum of the quality factor shift value and the reference quality factor value, the greater the ratio of the reference quality factor value.

[0373] For 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 in the selection step, the foreign substance detection device The quality factor value can be measured at multiple different frequencies within the 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 calculates the quality factor from the first maximum value to the second maximum 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 the first maximum quality factor value. can be defined.

[0374] Generally, 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 illustrating 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 measurement unit 1920, a quality factor gradient determination unit 1930, a foreign substance detection 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 components can be added or removed.

[0377] The peak frequency search unit 1910 detects that an object is placed in the charging area during the selection step. If this occurs, power transmission is interrupted and the frequency with the maximum quality factor value within the operating frequency band is selected. Here, the frequency for searching for the frequency with the 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 as the current peak frequency (F_current_peak). On the other hand, in a preliminary experiment, only the wireless power receiver was placed in the charging area. The frequency with the highest quality factor value obtained is called the reference peak frequency (F_reference We will 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 Start frequency (F_start), the current peak frequency searched, and the end frequency of the operating frequency band. The output voltage level of the resonant circuit can include at least one of the frequency (F_end). The voltage applied to the transmitting coil may be, but is not limited to, the output voltage level. The position at which the value is measured can vary depending on the design of the art.

[0379] The quality factor slope determining unit 1930 determines the slope of the specific 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 by:

[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 invention is described as being an embodiment of the present invention, this is merely an embodiment and other embodiments of the invention may be implemented 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 is The quality factor slope (Q_ In this case, the quality factor slope is calculated using the following formula:

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

[0385] It can be calculated by:

[0386] For the sake of convenience, the output voltage levels measured at the start frequency and the current peak frequency are used 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 is called the second quality factor slope. The output voltage level (or quality factor value) is calculated based on the measured output voltage level 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 substance detection unit 1940 compares the calculated quality factor slope with a predefined critical value. , foreign matter 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 gradient as a predefined The presence or absence of foreign matter can be determined by comparing the first quality factor slope critical value obtained. The first quality factor slope critical value may have a positive value.

[0389] As another example, the foreign substance detection unit 1940 may use the calculated second quality factor gradient 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 substance detection status packet of FIG. 15. Here, the first quality factor slope critical value is recorded in the reference value field. However, this is only an example, and the first item may be recorded in the foreign substance detection status packet. A new field can also be defined to record the quality factor slope critical value.

[0391] As yet another example, the foreign substance detection unit 1940 may detect the first quality factor slope and the second quality factor slope. The average value of the quality factor slope is calculated, and the calculated quality factor slope average value is compared with the 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

[0392] As shown in Figure 20 below, 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 material are placed together. It has a value greater than the absolute value.

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

[0394] The foreign substance 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 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 another example, the first quality factor slope critical value may be transmitted to the corresponding wireless device via a communication unit (not shown). It can also be received directly from the power receiver. Foreign object detection status packet (FOD) received from the wireless power receiver on the floor First quality factor via Object Detection (Status Packet) The child slope critical value and / or the 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 substance 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 foreign matter in the charging area. The alarm section (not shown) can be controlled by the alarm control unit.

[0399] After outputting the warning alarm, the control unit 1950 removes the detected foreign matter from the charging area. If the result of the monitoring 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 wireless power receiver. It can be controlled so that

[0400] FIG. 20 shows the slope of the quality factor depending on whether or not there is a foreign substance in the wireless charging system according to the present invention. FIG. 10 is a diagram for explaining a change.

[0401] Referring to FIG. 20, drawing number 2010 shows a state where only the wireless power receiver is placed in the charging area. Drawing number 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) is calculated by using the wireless power receiver alone in the area. 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 will use Q_slope and Q_slope' as the reference quality factors. We will name these 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 set to be greater than the reference quality factor slope of FIG. 2010. 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 selects 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 temporarily suspends power transmission before entering the ping phase. The maximum quality factor value is calculated from the measured values ​​at different frequencies within the operating frequency band. The current peak frequency can be searched and stored in a predetermined storage 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, please be aware that the operating frequency band is not compatible with the corresponding wireless charging This may vary depending on the system design and applicable standards.

[0408] The wireless power transmitter has a start frequency and a 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 output a power of 100 W at the output voltage level measured at the start frequency and the current peak frequency. The quality factor slope can be calculated based on the above (S2004). 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 divided by the difference between the current peak frequency and the start frequency. That is, the quality factor slope can be calculated using the following formula:

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

[0411] It can be calculated by:

[0412] The wireless power transmitting device compares the calculated quality factor slope with a predetermined quality factor slope threshold value. Then, it can be determined whether or not a foreign substance exists in the charging area (S2105).

[0413] If the foreign object is detected, the wireless power transmitting device stops transmitting the power signal and It can be controlled to output a predetermined warning alarm indicating that a quality defect has been detected. (S2106 and S2107).

[0414] If it is determined in step 2105 that no foreign matter is present, the wireless power transmitting device 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 selects an object placed in the charging area. can be sensed (S2111).

[0417] If an object is detected, the wireless power transmitter applies a low voltage (e.g., 0.5V to 2V) to the inverter 1120 to generate a plurality of 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 storage area. For 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. The quality factor value measured at the measurement start frequency is called 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 as specified. The data 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, please be aware that the operating frequency band is not compatible with the corresponding wireless charging This may vary depending on the system design and applicable standards.

[0421] The wireless power transmitter is measured at a specific frequency (start frequency) and the current peak frequency. A quality factor gradient 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 is.

[0424] The wireless power transmitting device compares the calculated quality factor slope with a predetermined quality factor slope threshold value. Then, it can be determined whether or not a foreign substance exists in the charging area (S2115).

[0425] In yet another embodiment, the predetermined quality factor slope threshold value is set to the value of the foreign matter as in the embodiment of FIG. It may be a value 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 angular unit value. do.

[0427] If the foreign object is detected, the wireless power transmitting device stops transmitting the power signal and It can be controlled to output a predetermined warning alarm indicating that a quality defect has been detected. (S2116 and S2117).

[0428] If it is determined in step 2115 that no foreign matter 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. The quality factor slope can also be calculated based on the quality factor values ​​measured in wavenumber. 19, instead of the output voltage measurement unit 1920 shown in FIG. 19, the start frequency, the current peak frequency, 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 contain and consist of:

[0430] The method according to the above-described embodiment is implemented in a program to be executed by a computer. The present invention can be stored in a computer-readable recording medium, and 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 fashion. And a functional program for implementing the above-mentioned method, The code and code segments are easily inferred by programmers skilled in the art to which the embodiments pertain. It is possible to argue that

[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 those skilled in the art that this can be achieved.

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

[0434] The foreign substance detection method according to the embodiment may include: The present invention is applicable to a wireless charging system that detects foreign objects located between the

Claims

1. In a wireless power transmitter, a wireless communication unit configured to communicate with the wireless power receiver; and a control unit; The control unit receiving a first foreign object status packet from the wireless power receiver; receiving a second foreign object status packet from the wireless power receiver; the first foreign object status packet includes one of a reference quality factor value and a reference peak frequency; the second foreign object status packet includes another one of the reference quality factor value and the reference peak frequency; transmitting a first foreign object detection indicator including a negative response signal in response to the first foreign object status packet based on one of the reference quality factor value and the reference peak frequency; transmitting a second foreign object detection indicator including the negative response signal in response to the second foreign object status packet based on another one of the reference quality factor value and the reference peak frequency; If no foreign object is detected as a result of detecting the foreign object using the reference quality factor value or the reference peak frequency, a first subsequent step of a charging procedure is performed; If a foreign object is present, at least one of the first foreign object detection indicator and the second foreign object detection indicator includes the negative response signal, and the wireless power transmitter proceeds to a second subsequent step of the charging procedure requesting termination of the charging procedure, or to a third subsequent step of the charging procedure other than termination of the charging procedure.

2. The wireless power transmitter of claim 1 , wherein the first subsequent step of the charging procedure means that a wireless power transmission step is performed.

3. the second subsequent step of the charging procedure means that wireless power transmission is temporarily interrupted; The wireless power transmitter of claim 1 , wherein the third subsequent stage of the charging procedure means that the wireless power transmission is not interrupted.

4. The wireless power transmitter of claim 1 , wherein the first and second foreign object detection indicators include the negative response signal when a measured peak frequency of a power signal transmitted by the wireless power transmitter is greater than a critical frequency.

5. The wireless power transmitter of claim 4 , wherein the critical frequency is determined by the wireless power transmitter based on the reference peak frequency.

6. 2. The wireless power transmitter of claim 1, wherein the first and second foreign object detection indicators include the negative response signal when a measured quality factor value of a power signal transmitted by the wireless power transmitter is equal to or less than a critical quality factor value.

7. The wireless power transmitter of claim 6 , wherein the critical quality factor value is determined by the wireless power transmitter based on the reference quality factor value.

8. The wireless power transmitter of claim 1 , wherein an intensity of the wireless power transmitted during the first subsequent step is different from an intensity of the wireless power transmitted during the second or third subsequent step.

9. The wireless power transmitter of claim 8 , wherein the intensity of the wireless power transmitted during the second or third subsequent step is lower than the intensity of the wireless power transmitted during the first subsequent step.

10. The wireless power transmitter of claim 1 , wherein the reference peak frequency comprises a frequency corresponding to a quality factor value within an operating frequency range of a reference wireless power transmitter.

Images