Foreign Substance Detection Method, Apparatus, and System Therefor

Abstract

To provide a method for detecting a foreign material while minimizing unnecessary power waste and a heating phenomenon due to a foreign object so as to allow effective and accurate detection of the foreign material, and a device and system therefor.SOLUTION: The method for detecting a foreign material in a wireless power transmitter provided with a resonance circuit for wirelessly transmitting power comprises the steps of: detecting an object disposed in a charging area; measuring a quality factor value of a resonance circuit, following the detection of the object; identifying a wireless power receiver by sending out a detection signal; determining a critical value for detecting a foreign material, on the basis of a reference quality factor value received from the identified wireless power receiver; and judging whether the foreign material exists, by comparing the measured quality factor value and the determined critical value. The critical value is determined by applying a weight which increases in accordance with the reference quality factor value.SELECTED DRAWING: Figure 9a

Description

[Technical Field]

[0001] The present invention relates to wireless power transmission technology, and more particularly to foreign object detection in wireless charging systems. The present invention relates to a method and an apparatus and system therefor. [Background technology]

[0002] In recent years, with the rapid development of information and communication technology, a ubiquitous society based on information and communication technology 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, energy transfer methods using wireless technology can be broadly classified into magnetic induction methods, electromagnetic resonance methods, and RF transmission methods using short-wavelength radio frequencies. ectromagnetic Resonance) methods, and RF transmission methods using short-wavelength radio frequencies. RF transmission methods, etc.

[0006] The magnetic induction method involves placing two coils adjacent to each other. When an electric current is passed through one coil, the magnetic flux generated at this time induces an electromotive force in the other coil. This is a technology that utilizes this phenomenon and has been quickly commercialized mainly for small devices such as mobile phones. The magnetic induction method can transmit power of up to several hundred kilowatts (kW) with high efficiency. However, since the maximum transmission distance is 1 centimeter (cm) or less, it generally has the drawback that it must be adjacent to a charger or the bottom surface.

[0007] The magnetic resonance method is characterized by using an electric field or a magnetic field instead of utilizing electromagnetic waves, electric currents, etc. Since the magnetic resonance method is hardly affected by electromagnetic wave problems, it has the advantage of being safe for other electronic devices and the human body. On the other hand, it can only be utilized within a limited distance and space, and has the drawback of slightly low energy transfer efficiency.

[0008] The short-wavelength wireless power transmission method, simply speaking, the RF transmission method, utilizes the fact that energy can be directly transmitted and received in the form of radio waves (Ra dio Wave). This technology is a wireless power transmission method of the RF type using a rectenna. A rectenna is a compound word of an antenna and a rectifier, meaning an element that directly converts RF power into DC power. That is, the RF method is an AC radio It is a technology that converts waves into DC and is used. Recently, as the efficiency has improved, research on commercialization has been actively progressing.

[0009] Wireless power transmission technology can be diversely utilized not only in mobile devices but also in various industries such as IT, railway, and home appliance industries.

[0010] When there is a conductor that is not a wireless power receiver, that is, FO (Foreign Object), in the wireless charging area, electromagnetic signals sent from the wireless power transmitter may be induced in the FO and the temperature may rise. As an example, the FO can include coins, clips, pins, ball pens, etc.

[0011] If there is an FO between the wireless power receiver and the wireless power transmitter, not only will the wireless charging efficiency drop drastically, but the temperatures of the wireless power receiver and the wireless power transmitter may rise together due to the temperature increase around the FO. If the FO located in the charging area is not removed, it will not only cause power waste but also can cause damage to the wireless power transmitter and the wireless power receiver due to overheating.

[0012] Therefore, accurately detecting the FO located in the charging area is an important issue in the field of wireless charging technology.

Summary of the Invention

Problems to be Solved by the Invention

[0013] The present invention was devised to solve the above-described problems of the prior art, and the object of the present invention is to provide a foreign substance detection method for wireless charging, an apparatus therefor, and a system therefor.

[0014] Another object of the present invention is to determine a critical value or a critical range for dynamically detecting foreign substances by reflecting a weighting value linearly or exponentially determined by a reference quality factor value, thereby providing a radio power transmission device capable of more accurately detecting foreign substances. Another object of the present invention is to provide a radio power transmission device capable of detecting foreign substances based on the quality factor value and the inductance value of a resonant circuit measured before the ping stage.

[0015] Another object of the present invention is to measure not only the quality factor value but also the inductance value of the resonant circuit before the ping stage when an object is detected in the charging area, and to compare the measured value with the critical value determined based on the FOD state packet in the negotiation stage, thereby providing a foreign substance detection method, an apparatus, and a system therefor capable of more accurately detecting foreign substances. Another object of the present invention is to provide a radio power transmitter capable of detecting foreign substances based on the quality factor value measured corresponding to a specific frequency within the operating frequency band. .

[0016] When an object is detected in the charging area, another object of the present invention is to measure not only the quality factor value but also the inductance value of the resonant circuit before the ping stage, and to compare the measured value with the critical value determined based on the FOD state packet in the negotiation stage, thereby providing a foreign substance detection method, an apparatus, and a system therefor capable of more accurately detecting foreign substances. Another object of the present invention is to provide a radio power transmitter capable of detecting foreign substances based on the average quality factor value measured corresponding to a specific frequency within the operating frequency band.

[0017]

[0018] The technical problems to be achieved by the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understandable to those having ordinary knowledge in the technical field to which the present invention belongs from the following description.

Means for Solving the Problems

[0019] The present invention can provide a foreign substance detection method, an apparatus therefor, and a system therefor.

[0020] A wireless power transmitter having a resonant circuit for wirelessly transmitting power according to an embodiment of the present invention The foreign substance detection method in includes a step of sensing an object disposed in a charging area, a step of measuring a quality factor value of the resonant circuit if the object is sensed, a step of sending a sensing signal to identify a wireless power receiver, a step of determining a threshold value for foreign substance detection based on a reference quality factor value received from the identified wireless power receiver, and a step of comparing the measured quality factor value with the determined threshold value to determine the presence or absence of a foreign substance, wherein the threshold value can be determined by applying a weighting value that increases according to the reference quality factor value. Here, the weighting value can increase linearly or exponentially according to the reference quality factor value. Also, a configuration factor corresponding to the wireless power transmitter and a predefined allowable error are further applied to the determination of the threshold value, and the threshold value can be determined by adding the allowable error to a value obtained by multiplying the reference quality factor value by the configuration factor and then subtracting the weighting value.

[0021] Also, the foreign substance detection method may further include, if the determination result is that no foreign substance is present, starting charging of the identified wireless power receiver, and if the determination result is that a foreign substance is present, interrupting power transmission through the resonant circuit and outputting a predetermined alarm signal indicating that a foreign substance has been sensed.

[0022]

[0023]

[0024] Also, if the power transmission is interrupted, it can return to the stage of sensing an object placed in the charging area. It can return.

[0025] Also, after the regression, the foreign substance detection method compares the measured quality factor value of the resonance circuit with the determined critical value to confirm whether the sensed foreign substance has been removed from the charging area. This can further include the step of confirmation.

[0026] Also, if the confirmation result shows that the foreign substance has been removed, the interrupted power transmission can be resumed. It can be resumed.

[0027] Also, the reference quality factor value can be included in and received by a foreign substance detection status packet received during the negotiation stage. It can be received.

[0028] Also, the step of determining the presence or absence of the foreign substance includes determining that no foreign substance exists if the measured quality factor value exceeds the critical value, and determining that a foreign substance exists if the measured quality factor value is below the critical value. This can be included.

[0029] A foreign substance detection method in a wireless power transmitter equipped with a resonance circuit for wirelessly transmitting power according to another embodiment of the present invention includes a step of sensing an object placed in a charging area, and if the object is sensed, a step of measuring the quality factor value of the resonance circuit, a step of sending a sensing signal to identify a wireless power receiver, a step of determining a critical range for foreign substance detection based on a reference quality factor value received from the identified wireless power receiver, and a step of comparing the measured quality factor value with the determined critical range to determine the presence or absence of a foreign substance. Based on the received reference quality factor value, a step of determining a critical range for foreign substance detection, a step of comparing the measured quality factor value with the determined critical range to determine the presence or absence of a foreign substance, and the above-mentioned critical range is compared with the measured quality factor value to determine the presence or absence of a foreign substance, and the above-mentioned critical The boundary range is determined by applying the upper and lower weights that increase depending on the reference quality factor value. It can be done.

[0030] According to another embodiment of the present invention, a foreign substance detection device includes a resonant capacitor and a resonant inductor. a resonant circuit including a resonator; a sensing unit for sensing an object placed in the charging area; and When a body is detected, a measurement unit measures the quality factor value of the resonant circuit, and a wireless power The foreign substance detection status is determined based on the reference quality factor value of the foreign substance detection status packet received from the receiver. and determining a critical value for the quality factor, and comparing the measured quality factor value with the determined critical value to determine differences. a control unit for determining whether or not a substance is present, wherein the critical value is increased by the reference quality factor value. The weighting factor can be applied to determine the weighting factor.

[0031] Here, the weight increases linearly or exponentially according to the reference quality factor value, and The threshold is predetermined to be a value obtained by multiplying the reference quality factor value by a configuration factor corresponding to the wireless power transmitter. can be determined by adding a defined tolerance and then subtracting the weighted value. do.

[0032] If it is determined that the foreign substance is not present, the control unit Charging of the receiver is started, and if it is determined that the foreign substance is present, the control unit A predetermined alarm signal is sent to interrupt power transmission through the circuit and indicate that a foreign object has been detected. The signal can be controlled to be output.

[0033] Further, the control unit returns to the selection stage after the power transmission is interrupted to measure the resonant circuit the quality factor value of the detected foreign matter is compared with the determined critical value, and It is possible to confirm whether it has been removed from.

[0034] Also, when the foreign substance is removed as a result of the confirmation, the control unit restarts the interrupted power transmission.

[0035] In addition, the foreign substance detection device includes a DC / DC converter that converts DC power applied from a power source into specific DC power, and an inverter that converts the converted DC power into AC power. Furthermore, when the measurement by the measurement unit is completed, the control unit controls the DC / DC converter and the inverter described above so that digital pinging for identifying the wireless power receiver is periodically transmitted. If a signal strength indicator corresponding to the digital pinging is received, the wireless power receiver can be identified.

[0036] Also, the measurement unit can measure the quality factor value of the resonance circuit based on the voltage measured at both ends of the resonance capacitor.

[0037] A foreign substance detection device according to still another embodiment of the present invention includes a resonance circuit including a resonance capacitor and a resonance inductor, a sensing unit that senses an object disposed in a charging area, a measurement unit that measures the quality factor value of the resonance circuit when the object is sensed, and a control unit that determines a critical range for foreign substance detection based on a reference quality factor value of a foreign substance detection status packet received from an identified wireless power receiver, and compares the measured quality factor value with the determined critical range to determine the presence or absence of a foreign substance. The critical range can be determined by applying an upper weighting value and a lower weighting value that increase according to the reference quality factor value.

[0038] ​​​​​​​A wireless power transmitter equipped with a resonant circuit for wirelessly transmitting power according to an embodiment of the present invention The foreign object detection method in comprises a step of measuring a first inductance value of the resonant circuit, and a step of receiving a foreign object detection state packet from a wireless power receiver, and a step of determining a threshold value for foreign object detection based on the foreign object detection state packet, and a step of comparing the measured first inductance value with the determined threshold value to determine the presence or absence of a foreign object.

[0039] Also, the foreign object detection method may further include a step of sensing an object disposed in the charging area and a step of identifying the wireless power receiver, and the measured first inductance value may include the inductance value of the resonant circuit changed by the sensed object.

[0040] Also, the first inductance value can be measured before entering the step of identifying the wireless power receiver after the object is sensed.

[0041] Also, the foreign object detection method may further include a step of measuring a quality factor value of the co-moving circuit before entering the step of identifying the wireless power receiver after the object is sensed.

[0042] Also, the foreign object detection method may further include a step of interrupting power transmission to the wireless power receiver based on the determination result of the presence or absence of the foreign object.

[0043] Also, the foreign object detection method may further include a step of correcting the power transmitted to the identified wireless power receiver based on the determination result of the presence or absence of the foreign object.

[0044] ​​​​​​​​​​​Further, the foreign substance detection method may further include a step of outputting an alarm signal indicating that a foreign substance has been detected based on the determination result of the presence or absence of the foreign substance.

[0045] Further, the foreign substance detection method may further include a step of detecting an object disposed in the charging area after the power transmission interruption.

[0046] Further, the foreign substance detection method includes, after the power transmission interruption, measuring a value of a second inductor of the resonance circuit, and comparing the measured value of the second inductor with the determined critical value to determine whether the detected foreign substance has been removed from the charging area.

[0047] Further, the foreign substance detection status packet may include at least one of a reference quality factor value and a reference inductance value.

[0048] Further, the reference inductance value may include an inductance value of the resonance circuit measured when the wireless power receiver is located in the charging area in the absence of a foreign substance.

[0049] In one embodiment, the foreign substance detection status packet further includes a mode field, and the mode field may include a first mode indicating that the foreign substance detection status packet includes the reference inductance value.

[0050] In another embodiment, the foreign substance detection status packet further includes a mode field, and the mode field may include a second mode indicating that the foreign substance detection status packet includes the reference inductance value and the reference quality factor value. ​

[0051] Also, the determined critical values include a quality factor critical value and an inductance critical value, and the quality factor critical value and the inductance critical value can include values that are smaller than the respective reference quality factor value and reference inductance value by a preset ratio.

[0052] Also, the determined critical value can include a value that is larger than the reference inductance value by a preset ratio.

[0053] Also, the foreign substance detection method further includes a step of receiving a received power intensity packet for correcting the power from the wireless power receiver, and the received power intensity packet can include the received power of the wireless power receiver corresponding to the load or the received power of the wireless power receiver corresponding to the load connection state.

[0054] Also, the step of determining the presence or absence of the foreign substance includes a first foreign substance determination step of comparing the measured quality factor value with the quality factor critical value to determine the presence or absence of the foreign substance, and the measured first inductance value is compared with the inductance critical value to determine the presence or absence of the foreign substance.

[0055] Also, if it is determined that a foreign substance is present in at least one foreign substance determination step of the first foreign substance determination step and the second foreign substance determination step, it can be finally determined that a foreign substance is present.

[0056] A foreign substance detection device according to another embodiment of the present invention includes a resonance circuit including a resonance capacitor and an inductor, a charging region disposed on the inductor, and a first inductance of the resonance circuit. ​ A measuring unit that measures an inductance value, and based on a foreign substance detection state packet received from a wireless power receiver determines a threshold value for foreign substance detection, and a control unit that compares the measured first inductance value with the previously determined threshold value to determine the presence or absence of a foreign substance can be included. 。

[0057] Further, the control unit is set to sense an object located in the charging area, and the measured first inductance value can include the inductance value of the resonance circuit changed by the sensed object.

[0058] Further, the measuring unit is set to measure the quality factor value of the co-resonant circuit, and the measured quality factor value can include the quality factor value of the resonance circuit changed by the sensed object.

[0059] Further, the inductance value of the co-resonant circuit can include the inductance value of the inductor.

[0060] Further, if the measured first inductance value is greater than the determined threshold value, the control unit can correct the power transmitted to the wireless power receiver.

[0061] Further, if the measured first inductance value is the same as or less than the determined threshold value, the control unit can control to interrupt the power transmission to the wireless power receiver.

[0062] Further, the foreign substance detection state packet can include at least one of a reference quality factor value and a reference inductance value.

[0063] In one embodiment, the foreign substance detection status packet further includes a mode field, and the mo de field can include a first mode indicating that the foreign substance detection status packet includes the reference inductance value.

[0064] In another embodiment, the foreign substance detection status packet further includes a mode field, and the mo de field can include a second mode indicating that the foreign substance detection status packet includes the reference inductance value and the reference quality factor value.

[0065] Also, the determined critical value includes a quality factor critical value and an inductance critical value, and the quality factor critical value and the inductance critical value can include values that are smaller than the reference quality factor value and the reference inductance value by a preset ratio, respectively.

[0066] Also, the determined critical value can include a value that is larger than the reference inductance value by a preset ratio.

[0067] Also, the control unit can perform a first foreign substance determination for comparing the measured quality factor value with the quality factor critical value to determine the presence or absence of a foreign substance, and a second foreign substance determination for comparing the measured inductance value with the inductance critical value to determine the presence or absence of a foreign substance.

[0068] Also, if it is determined that a foreign substance exists based on at least one of the first foreign substance determination and the second foreign substance determination, the control unit can finally determine that a foreign substance exists.

[0069] Further, the foreign substance detection device converts the DC power applied from the power supply into specific DC power. It further includes a DC / DC converter that converts the converted DC power into AC power, and an inverter that converts the converted DC power into AC power. When the measurement by the measurement unit is completed, the control unit controls the DC / DC converter and the inverter described above so that digital pinging for identifying the wireless power receiver is periodically transmitted. If a signal strength indicator corresponding to the digital pinging is received, the wireless power receiver can be identified.

[0070] Also, the measurement unit can measure the first inductance value based on at least one of the voltage, current, and impedance measured at both ends of the resonance capacitor.

[0071] The measurement unit may include a quality factor measurement unit that calculates the quality factor value based on the voltage measured at both ends of the resonance capacitor, and an inductance measurement unit that calculates the inductance value based on the voltage and current measured at both ends of the inductor.

[0072] A foreign substance detection method in a wireless power transmitter according to an embodiment of the present invention may include measuring a first quality factor value for a first frequency, measuring a second quality factor value for a second frequency, and determining the presence state of a foreign substance on the charging area based on the first quality factor value and the second quality factor value.

[0073] As an example, if the second frequency is greater than the first frequency and the second quality factor value is greater than the first quality factor value, it can be determined that a foreign substance exists in the charging area. ​​​​​​​​​​​​

[0074] As another example, if the second quality factor value is greater than the first quality factor value, it can be determined that there is a radio power receiver not aligned in the charging area.

[0075] Further, the foreign substance detection method further includes a step of transmitting radio power according to the determined state of existence of the foreign substance, and the state of presence or absence of the foreign substance can include a state of presence of the foreign substance and a state of absence of the foreign substance.

[0076] Further, the state of presence of the foreign substance can include a state in which the second quality factor value is greater than the first quality factor value.

[0077] Further, the state of absence of the foreign substance can include a state in which the second quality factor value is the same as or smaller than the first quality factor value.

[0078] Further, the foreign substance detection method can further include a step of outputting a predetermined alarm signal if the presence of a foreign substance is sensed in the charging area based on the determination result.

[0079] Further, the foreign substance detection method can further include a step of temporarily interrupting power transmission when the presence of the foreign substance is sensed during power transmission.

[0080] Further, the foreign substance detection method further includes a step of confirming whether the sensed foreign substance has been removed from the charging area in a state where the power transmission has been temporarily interrupted, and if the confirmed result is that the sensed foreign substance has been removed, the temporarily interrupted power transmission can be resumed.

[0081] Further, after outputting the alarm signal, the foreign substance detection method enters a selection step.​​​​​​​​​ It can further include.

[0082] In addition, after outputting the alarm signal and before entering the selection stage, the foreign substance detection method further includes a step of checking whether the sensed foreign substance has been removed from the charging area, and if the check result shows that the foreign substance has been removed, it can enter the selection stage.

[0083] In addition, if the value obtained by subtracting the first quality factor value from the second quality factor value exceeds a predetermined reference value, it can be determined that there is a foreign substance in the charging area.

[0084] A foreign substance detection method in a wireless power transmitter according to another embodiment of the present invention includes calculating a first quality factor average value corresponding to a predetermined upper frequency band within an operating frequency band, calculating a second quality factor average value corresponding to a predetermined lower frequency band within the operating frequency band, and determining whether there is a foreign substance in the charging area of the wireless power transmitter based on the first quality factor average value and the second quality factor average value. Based on the first quality factor average value and the second quality factor average value described above, it can include a step of determining whether there is a foreign substance in the charging area of the wireless power transmitter. It can include.

[0085] As an example, if the first quality factor average value is greater than the second quality factor average value, it can be determined that there is a foreign substance in the charging area.

[0086] As another example, if the value obtained by subtracting the second quality factor average value from the first quality factor average value exceeds a predetermined reference value, it can also be determined that there is a foreign substance in the charging area.

[0087] A foreign substance detection device provided in a wireless power transmitter according to still another embodiment of the present invention measures a first quality factor value for a first frequency within a preset operating frequency band, and the operating frequency measures a first quality factor value for a first frequency within a preset operating frequency band, and the operating frequency A quality factor measurement unit that measures a second quality factor value for a second frequency within a wave number band, and the first Based on the quality factor value and the second quality factor value, it can include a detection unit that determines whether there is a foreign substance in the charging area.

[0088] As an example, if the second frequency is greater than the first frequency and the second quality factor value is greater than the first quality factor value, the detection unit can determine that there is a foreign substance in the charging area.

[0089] As another example, if the second frequency is greater than the first frequency and the second quality factor value is greater than the above-mentioned first quality factor value, the detection unit can also determine that there is a misaligned wireless power receiver in the charging area.

[0090] In addition, if the foreign substance detection device senses that there is a foreign substance in the charging area based on the determination result, it can further include an alarm unit that outputs a predetermined alarm signal.

[0091] In addition, when the presence of the foreign substance is sensed, if the power is being transmitted, the foreign substance detection device can further include a control unit that temporarily interrupts the power transmission.

[0092] In addition, the control unit checks whether the sensed foreign substance has been removed from the charging area in the state where the power transmission has been temporarily interrupted, and if the confirmation result shows that the sensed foreign substance has been removed, the temporarily interrupted power transmission can also be resumed.

[0093] In addition, the control unit can control to enter the selection stage after the output of the alarm signal.

[0094] ​​​​​​​Also, after the output of the alarm signal and before entering the selection stage, the control unit senses the charged foreign substance to confirm whether it has been removed from the charging area. If the confirmation result indicates that the foreign substance has been removed, it can be controlled to enter the selection stage.

[0095] Also, if the second frequency is greater than the first frequency and the value obtained by subtracting the first quality factor value from the second quality factor value exceeds a predetermined reference value, the detection unit can determine that there is a foreign substance in the charging area.

[0096] A foreign substance detection device provided in a wireless power transmitter according to still another embodiment of the present invention includes a quality factor measurement unit that measures a quality factor value within a predetermined operating frequency band, an average calculation unit that calculates a first average quality factor value based on at least one of the quality factor values measured corresponding to a predetermined upper limit frequency band within the operating frequency band, and calculates a second average quality factor value based on at least one of the quality factor values measured corresponding to a predetermined lower limit frequency band within the operating frequency band, and a detection unit that determines whether there is a foreign substance in the charging area of the wireless power transmitter based on the first average quality factor value and the second average quality factor value.

[0097] As an example, if the first average quality factor value is greater than the second average quality factor value, the detection unit can determine that there is a foreign substance in the charging area.

[0098] As another example, if the value obtained by subtracting the second average quality factor value from the first average quality factor value exceeds a predetermined reference value, the detection unit can also determine that there is a foreign substance in the charging area.

[0099] Still another embodiment of the present invention can provide a computer-readable recording medium having a program recorded thereon for executing any one of the foreign substance detection methods described above.

[0100] The aspects of the present invention are merely a part of the preferred embodiments of the present invention, and various embodiments reflecting the technical features of the present invention can be derived and understood from the detailed description of the present invention to be described in detail below by those having ordinary knowledge in the art.

Advantages of the Invention

[0101] The effects of the method, apparatus, and system according to the present invention are as follows.

[0102] The present invention provides an advantage of a foreign substance detection method for wireless charging and an apparatus and a system therefor.

[0103] In addition, the present invention has an advantage of providing a foreign substance detection method and an apparatus and a system therefor that can detect foreign substances more accurately.

[0104] In addition, the present invention has an advantage of being able to minimize unnecessary power waste and heat generation due to foreign substances.

[0105] In addition, the present invention determines a critical value or a critical range for dynamically detecting foreign substances by reflecting a weighting value linearly or exponentially determined by a reference quality factor value, thereby providing an advantage of providing a wireless power transmission device capable of detecting foreign substances more accurately.

[0106] In addition, the present invention provides a wireless power transmission device capable of detecting foreign substances based on the quality factor value and the inductance value of a resonance circuit measured before the ping stage. ​

[0107] In addition, the present invention detects the quality factor of the resonant circuit before the ping step if an object is detected in the charging area. Measures inductance values, not just child values, and determines them based on the FOD status packet during the negotiation phase. By comparing the measured value with the critical value determined by the It would be advantageous to provide a possible foreign substance detection method and an apparatus and system therefor.

[0108] In addition, the present invention dynamically determines whether or not a foreign substance exists depending on the type of receiver. A foreign substance detection method that can detect foreign substances more accurately by determining the value and a method using the same It would be advantageous to provide an apparatus and system that:

[0109] The present invention also provides a method for determining a quality factor based on a measured quality factor value corresponding to a specific frequency within the operating frequency band. It would be advantageous to provide a wireless power transmitter that is capable of detecting foreign matter.

[0110] The present invention also provides a method for calculating the average quality factor of a specific frequency within the operating frequency band. It would be advantageous to provide a wireless power transmitter capable of detecting foreign matter based on the power of the transmitter.

[0111] Furthermore, the present invention not only has the advantage of minimizing foreign substance detection errors, but also It is expected that unnecessary power consumption and equipment damage can be minimized.

[0112] 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]

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Mode for Carrying Out the Invention

[0150] In a wireless power transmitter equipped with a resonance circuit for wirelessly transmitting power according to an embodiment The foreign substance detection method includes a step of sensing an object arranged in a charging area, and if the object is sensed Then, a step of measuring the quality factor value of the resonance circuit, a step of sending a sensing signal to identify a wireless power receiver Based on the reference quality factor value received from the identified wireless power receiver Determining a threshold value for foreign substance detection, and comparing the measured quality factor value with the determined a step of comparing the obtained critical value to determine the presence or absence of a foreign substance, wherein the critical value can be determined by applying a weighted value that increases according to the quality factor value. The weighted value that increases according to the quality factor value can be applied for determination. Embodiment for Carrying out the Invention

[0151] Hereinafter, apparatuses and various methods to which embodiments of the present invention are applied will be described in more detail with reference to the drawings. For the components used in the following description, the suffixes “module” and “unit” are given or mixed only for ease of specification writing, and do not have distinct meanings or roles as such. For ease of specification writing, the suffixes “module” and “unit” are given or mixed, and do not have distinct meanings or roles as such. They do not have distinct meanings or roles from each other.

[0152] In the description of the embodiment, when it is described as being formed “above or below” each component, “above or below” includes all cases where two components are in direct contact with each other or where one or more additional components are arranged between the two components. When two components are in direct contact with each other or when one or more additional components are arranged between the two components, it is included. Also, when expressed as “above or below”, it can include not only the meaning above but also the meaning below with respect to one component. When expressed as “above or below”, it can include not only the meaning above but also the meaning below with respect to one component. When expressed as “above or below”, it can include not only the meaning above but also the meaning below with respect to one component.

[0153] In the description of the embodiment, for the sake of convenience of explanation, a device equipped with a function of transmitting wireless power on a wireless charging system may be used interchangeably with a wireless power transmitter, a wireless power transmission device, a wireless power transmission apparatus, a wireless power transmitter, a transmission end, a transmitter, a transmission device, a transmission side, a wireless power transmission device, a wireless power transmitter, etc. For the sake of convenience of explanation, a device equipped with a function of transmitting wireless power on a wireless charging system may be used interchangeably with a wireless power transmitter, a wireless power transmission device, a wireless power transmission apparatus, a wireless power transmitter, a transmission end, a transmitter, a transmission device, a transmission side, a wireless power transmission device, a wireless power transmitter, etc. For the sake of convenience of explanation, a device equipped with a function of transmitting wireless power on a wireless charging system may be used interchangeably with a wireless power transmitter, a wireless power transmission device, a wireless power transmission apparatus, a wireless power transmitter, a transmission end, a transmitter, a transmission device, a transmission side, a wireless power transmission device, a wireless power transmitter, etc. For the sake of convenience of explanation, a device equipped with a function of transmitting wireless power on a wireless charging system may be used interchangeably with a wireless power transmitter, a wireless power transmission device, a wireless power transmission apparatus, a wireless power transmitter, a transmission end, a transmitter, a transmission device, a transmission side, a wireless power transmission device, a wireless power transmitter, etc. For the sake of convenience of explanation, a device equipped with a function of receiving wireless power from a wireless power transmission device may be used interchangeably with a wireless power receiving device, a wireless power receiver, a wireless power receiving apparatus, a wireless power receiver, a receiving terminal device, a receiving side, a receiving device, a receiver, etc. For the sake of convenience of explanation, a device equipped with a function of receiving wireless power from a wireless power transmission device may be used interchangeably with a wireless power receiving device, a wireless power receiver, a wireless power receiving apparatus, a wireless power receiver, a receiving terminal device, a receiving side, a receiving device, a receiver, etc. For the sake of convenience of explanation, a device equipped with a function of receiving wireless power from a wireless power transmission device may be used interchangeably with a wireless power receiving device, a wireless power receiver, a wireless power receiving apparatus, a wireless power receiver, a receiving terminal device, a receiving side, a receiving device, a receiver, etc.

[0154] The transmitter according to the present invention can be configured in a pad form, a stationary form, an AP (Access Point) form, a small base station form, a stand form, a ceiling-embedded form, a wall-mounted form, etc., and one transmitter can also transmit power to a plurality of wireless power receiving devices. For this reason, the transmitter can also be provided with at least one wireless power transmission means. Here, the wireless power transmission means charges based on the electromagnetic induction method that generates a magnetic field with a power transmission end coil and induces electricity in the receiving end coil by the influence of the magnetic field. A variety of wireless power transmission standards can be used. Here, the wireless power transmission means can include wireless charging technologies of the electromagnetic induction method defined by the wireless charging technology standard organizations WPC (Wireless Power Consortium) and PMA (Power Matters Alliance). The receiver according to an embodiment of the present invention can be provided with at least one wireless power receiving means and can also receive wireless power from two or more transmitters simultaneously. Here, the wireless power receiving means can include wireless charging technologies of the electromagnetic induction method defined by the wireless charging technology standard organizations WPC (Wireless Power Consortium) and PMA (Power Matters Alliance). The receiver according to the present invention can be a mobile phone, a smart phone, a laptop computer, a digital broadcast terminal, a PDA (Personal Digital Assistant), etc. For this reason, the transmitter can also be provided with at least one wireless power transmission means. Here, the wireless power transmission means generates a magnetic field with a power transmission end coil, and charges based on the electromagnetic induction principle in which electricity is induced in the receiving end coil by the influence of the magnetic field. A variety of wireless power transmission standards can be used. Here, the wireless power transmission means can include wireless charging technologies of the electromagnetic induction method defined by the wireless charging technology standard organizations WPC (Wireless Power Consortium) and PMA (Power Matters Alliance). The wireless power transmission means generates a magnetic field with a power transmission end coil, and charges based on the electromagnetic induction principle in which electricity is induced in the receiving end coil by the influence of the magnetic field. A variety of wireless power transmission standards can be used. Here, the wireless power transmission means can include wireless charging technologies of the electromagnetic induction method defined by the wireless charging technology standard organizations WPC (Wireless Power Consortium) and PMA (Power Matters Alliance). For this reason, the transmitter can also be provided with at least one wireless power transmission means. Here, the wireless power transmission means generates a magnetic field with a power transmission end coil, and charges based on the electromagnetic induction principle in which electricity is induced in the receiving end coil by the influence of the magnetic field. A variety of wireless power transmission standards can be used. Here, the wireless power transmission means can include wireless charging technologies of the electromagnetic induction method defined by the wireless charging technology standard organizations WPC (Wireless Power Consortium) and PMA (Power Matters Alliance). The receiver according to an embodiment of the present invention can be provided with at least one wireless power receiving means and can also receive wireless power from two or more transmitters simultaneously. Here, the wireless power receiving means can include wireless charging technologies of the electromagnetic induction method defined by the wireless charging technology standard organizations WPC (Wireless Power Consortium) and PMA (Power Matters Alliance). The receiver according to the present invention can be a mobile phone, a smart phone, a laptop computer, a digital broadcast terminal, a PDA (Personal Digital Assistant), etc. The wireless power transmission means generates a magnetic field with a power transmission end coil, and charges based on the electromagnetic induction principle in which electricity is induced in the receiving end coil by the influence of the magnetic field. A variety of wireless power transmission standards can be used. Here, the wireless power transmission means can include wireless charging technologies of the electromagnetic induction method defined by the wireless charging technology standard organizations WPC (Wireless Power Consortium) and PMA (Power Matters Alliance). For this reason, the transmitter can also be provided with at least one wireless power transmission means. Here, the wireless power transmission means generates a magnetic field with a power transmission end coil, and charges based on the electromagnetic induction principle in which electricity is induced in the receiving end coil by the influence of the magnetic field. A variety of wireless power transmission standards can be used. Here, the wireless power transmission means can include wireless charging technologies of the electromagnetic induction method defined by the wireless charging technology standard organizations WPC (Wireless Power Consortium) and PMA (Power Matters Alliance).

[0155] The receiver according to an embodiment of the present invention can be provided with at least one wireless power receiving means and can also receive wireless power from two or more transmitters simultaneously. Here, the wireless power receiving means can include wireless charging technologies of the electromagnetic induction method defined by the wireless charging technology standard organizations WPC (Wireless Power Consortium) and PMA (Power Matters Alliance). The wireless power receiving means generates a magnetic field with a power transmission end coil, and charges based on the electromagnetic induction principle in which electricity is induced in the receiving end coil by the influence of the magnetic field. A variety of wireless power transmission standards can be used. Here, the wireless power receiving means can include wireless charging technologies of the electromagnetic induction method defined by the wireless charging technology standard organizations WPC (Wireless Power Consortium) and PMA (Power Matters Alliance). The receiver according to the present invention can be a mobile phone, a smart phone, a laptop computer, a digital broadcast terminal, a PDA (Personal Digital Assistant), etc. The wireless power receiving means generates a magnetic field with a power transmission end coil, and charges based on the electromagnetic induction principle in which electricity is induced in the receiving end coil by the influence of the magnetic field. A variety of wireless power transmission standards can be used. Here, the wireless power receiving means can include wireless charging technologies of the electromagnetic induction method defined by the wireless charging technology standard organizations WPC (Wireless Power Consortium) and PMA (Power Matters Alliance). For this reason, the transmitter can also be provided with at least one wireless power transmission means. Here, the wireless power transmission means generates a magnetic field with a power transmission end coil, and charges based on the electromagnetic induction principle in which electricity is induced in the receiving end coil by the influence of the magnetic field. A variety of wireless power transmission standards can be used. Here, the wireless power transmission means can include wireless charging technologies of the electromagnetic induction method defined by the wireless charging technology standard organizations WPC (Wireless Power Consortium) and PMA (Power Matters Alliance).

[0156] The receiver according to the present invention can be a mobile phone, a smart phone, a laptop computer, a digital broadcast terminal, a PDA (Personal Digital Assistant), etc. The wireless power receiving means generates a magnetic field with a power transmission end coil, and charges based on the electromagnetic induction principle in which electricity is induced in the receiving end coil by the influence of the magnetic field. A variety of wireless power transmission standards can be used. Here, the wireless power receiving means can include wireless charging technologies of the electromagnetic induction method defined by the wireless charging technology standard organizations WPC (Wireless Power Consortium) and PMA (Power Matters Alliance). For this reason, the transmitter can also be provided with at least one wireless power transmission means. Here, the wireless power transmission means generates a magnetic field with a power transmission end coil, and charges based on the electromagnetic induction principle in which electricity is induced in the receiving end coil by the influence of the magnetic field. A variety of wireless power transmission standards can be used. Here, the wireless power transmission means can include wireless charging technologies of the electromagnetic induction method defined by the wireless charging technology standard organizations WPC (Wireless Power Consortium) and PMA (Power Matters Alliance). nts), PMP (Portable Multimedia Player), navigation -tion, MP3 player, electric toothbrush, electronic tag, lighting device, remote control ler, floating object, wearable devices such as smartwatches, and other small electronic devices can be used, but not limited to this. As long as the device is equipped with the wireless power receiving means according to the present invention and can be battery-charged, it is sufficient.

[0157] FIG. 1 is a block diagram for explaining a wireless charging system according to an embodiment of the present invention.

[0158] Referring to FIG. 1, the wireless charging system can mainly include a wireless power transmitting end 10 that wirelessly transmits power, a wireless power receiving end 20 that receives the transmitted power, and an electronic device 30 to which the received power is supplied.

[0159] As an example, the wireless power transmitting end 10 and the wireless power receiving end 20 can perform in-band communication that exchanges information using the same frequency band as the operating frequency used for wireless power transmission.

[0160] In in-band communication, if the power signal 41 transmitted by the wireless power transmitting end 10 is received by the wireless power receiving end 20, the wireless power receiving end 20 modulates the received power signal, and the modulated signal 42 can be transmitted to the wireless power transmitting end 10.

[0161] As another example, the wireless power transmitting end 10 and the wireless power receiving end 20 can also perform out-of-band communication that exchanges information using a separate frequency band different from the operating frequency used for wireless power transmission.

[0162] As an example, the information exchanged between the wireless power transmitter 10 and the wireless power receiver 20 can include not only the status information but also the control information between them. Here, the status information and the control information exchanged between the transmitter and the receiver will be made clearer by the description of the embodiments described later. The in-band communication and the out-of-band communication can provide two-way communication, but are not limited thereto. In other embodiments, one-way communication or half-duplex communication can also be provided. The status information and the control information exchanged between the transmitter and the receiver will be made clearer by the description of the embodiments described later.

[0163] The in-band communication and the out-of-band communication can provide two-way communication, but are not limited thereto. In other embodiments, one-way communication or half-duplex communication can also be provided. The in-band communication and the out-of-band communication can provide two-way communication, but are not limited thereto. In other embodiments, one-way communication or half-duplex communication can also be provided.

[0164] As an example, one-way communication can be that the wireless power receiver 20 transmits information only to the wireless power transmitter 10, but is not limited thereto, and the wireless power transmitter 10 can also transmit information to the wireless power receiver 20. As an example, one-way communication can be that the wireless power receiver 20 transmits information only to the wireless power transmitter 10, but is not limited thereto, and the wireless power transmitter 10 can also transmit information to the wireless power receiver 20.

[0165] The half-duplex communication method has the feature that two-way communication between the wireless power receiver 20 and the wireless power transmitter 10 is possible, but information transmission is possible only by any one device at any given time. The half-duplex communication method has the feature that two-way communication between the wireless power receiver 20 and the wireless power transmitter 10 is possible, but information transmission is possible only by any one device at any given time.

[0166] The wireless power receiver 20 according to an embodiment of the present invention can also acquire various status information of the electronic device 30. As an example, the status information of the electronic device 30 can include current power consumption information, information for identifying the application being executed, CPU usage information, battery charge status information, battery output voltage / current information, etc., but is not limited thereto, and any information that can be acquired from the electronic device 30 and can be utilized for wireless power control is sufficient. The wireless power receiver 20 according to an embodiment of the present invention can also acquire various status information of the electronic device 30. As an example, the status information of the electronic device 30 can include current power consumption information, information for identifying the application being executed, CPU usage information, battery charge status information, battery output voltage / current information, etc., but is not limited thereto, and any information that can be acquired from the electronic device 30 and can be utilized for wireless power control is sufficient. The wireless power receiver 20 according to an embodiment of the present invention can also acquire various status information of the electronic device 30. As an example, the status information of the electronic device 30 can include current power consumption information, information for identifying the application being executed, CPU usage information, battery charge status information, battery output voltage / current information, etc., but is not limited thereto, and any information that can be acquired from the electronic device 30 and can be utilized for wireless power control is sufficient. The wireless power receiver 20 according to an embodiment of the present invention can also acquire various status information of the electronic device 30. As an example, the status information of the electronic device 30 can include current power consumption information, information for identifying the application being executed, CPU usage information, battery charge status information, battery output voltage / current information, etc., but is not limited thereto, and any information that can be acquired from the electronic device 30 and can be utilized for wireless power control is sufficient.

[0167] In particular, the wireless power transmitter 10 according to an embodiment of the present invention can transmit a predetermined packet instructing whether fast charging is supported to the wireless power receiver 20. The wireless power receiver 20 is connected. In particular, the wireless power transmitter 10 according to an embodiment of the present invention can transmit a predetermined packet instructing whether fast charging is supported to the wireless power receiver 20. The wireless power receiver 20 is connected. ​​​When it is confirmed that the provided wireless power transmitter 10 supports the fast charging mode, this can be notified to the electronic device 30. The electronic device 30 can display that fast charging is possible via a provided predetermined display means, for example, a display means that can be a liquid crystal display.

[0168] Also, the user of the electronic device 30 can select a predetermined fast charging request button displayed on the liquid crystal display means to control the wireless power transmitter 10 to operate in the fast charging mode. In this case, when the fast charging request button is selected by the user, the electronic device 30 can transmit a predetermined fast charging request signal to the wireless power receiving end 20. The wireless power receiving end 20 can generate a charging mode packet corresponding to the received fast charging request signal and transmit it to the wireless power transmitter 10 to convert the general low power charging mode to the fast charging mode. can.

[0169] FIG. 2 is a state transition diagram for explaining the wireless power transmission process according to an embodiment of the present invention.

[0170] Referring to FIG. 2, the power transmission from the transmitter to the receiver can be roughly divided into a selection stage (Selec tion Phase) 210, a ping phase (Ping Phase) 220, an identification and configuration stage (Identification and Configuration Ph ase) 230, a negotiation phase (Negotiation Phase) 240, a calibration phase ([[]] Calibration Phase) 250, a power transmission phase (Power Trans fer Phase) 260, and a renegotiation phase (Renegotiation Phase ) 270.

[0171] The selection stage 210 can be a stage that transitions when a specific error or a specific event is detected while starting or maintaining power transmission. Here, the specific error and the specific event will be clarified by the following description. Also, at the selection stage 210, the transmitter can monitor whether an object is present on the interface surface. If it is assumed that the transmitter senses that an object is placed on the interface surface, it can transition to the ping stage 22 0. At the selection stage 210, the transmitter transmits a very short - pulse analog ping signal and can sense whether an object is present in the active area of the interface surface based on the current change of the transmitting coil or the primary coil. ry Coil) Area)

[0172] At the ping stage 220, if the transmitter senses an object, it activates the receiver and transmits a digital ping to identify whether the receiver is a receiver compatible with the WP PC standard. At the ping stage 220, if the transmitter cannot receive a response signal, such as a signal - strength packet, for the digital ping from the receiver, it can transition back to the selection stage 210. Also, at the ping stage 220, if the transmitter receives a signal indicating that the power transmission is completed from the receiver, that is, a charge - completed packet, it can also transition to the selection stage 210. When the ping stage 220 is completed, the transmitter can identify the receiver and transition to the identification and configuration stage 230 for collecting receiver configuration and status information. 210.

[0173] Once the ping stage 220 is completed, the transmitter can identify the receiver and transition to the identification and configuration stage 230 for collecting receiver configuration and status information.

[0174] ​​ In the identification and configuration stage 230, when the transmitter receives an unexpected packet, times out (i.e., the desired packet is not received within a predefined time), encounters a packet transmission error, or has no power transfer contract, it can transition to the selection stage 210. The transmitter can check whether it is necessary to enter the negotiation stage 240 based on the value in the negotiation field of the configuration packet received in the identification and configuration stage 230. If the result of the check indicates that negotiation is required, the transmitter can enter the negotiation stage 240 and perform a predetermined FOD detection process. On the other hand, if the result of the check indicates that negotiation is not required, the transmitter can immediately enter the power transmission stage 260. In the negotiation stage 240, the transmitter can receive an FOD (Foreign Object Detection) status packet containing a reference quality factor value. At this time, the transmitter can determine a threshold value for FO detection based on the reference quality factor value. For example, the transmitter can use a predetermined threshold generation function with the reference quality factor value as a mediating variable to determine a threshold value or a threshold range for determining the presence or absence of foreign substances. Here, the threshold value or threshold range calculated by the threshold generation function is a value smaller than the reference quality factor value.

[0175] The transmitter can check whether it is necessary to enter the negotiation stage 240 based on the value in the negotiation field of the configuration packet received in the identification and configuration stage 230. If the result of the check indicates that negotiation is required, the transmitter can enter the negotiation stage 240 and perform a predetermined FOD detection process. On the other hand, if the result of the check indicates that negotiation is not required, the transmitter can immediately enter the power transmission stage 260.

[0176] In the negotiation stage 240, the transmitter can receive an FOD (Foreign Object Detection) status packet containing a reference quality factor value. At this time, the transmitter can determine a threshold value for FO detection based on the reference quality factor value. For example, the transmitter can use a predetermined threshold generation function with the reference quality factor value as a mediating variable to determine a threshold value or a threshold range for determining the presence or absence of foreign substances. Here, the threshold value or threshold range calculated by the threshold generation function is a value smaller than the reference quality factor value. In the negotiation stage 240, the transmitter can receive an FOD (Foreign Object Detection) status packet containing a reference quality factor value. At this time, the transmitter can determine a threshold value for FO detection based on the reference quality factor value. For example, the transmitter can use a predetermined threshold generation function with the reference quality factor value as a mediating variable to determine a threshold value or a threshold range for determining the presence or absence of foreign substances. Here, the threshold value or threshold range calculated by the threshold generation function is a value smaller than the reference quality factor value.

[0177] In the negotiation stage 240, the transmitter can receive an FOD (Foreign Object Detection) status packet containing a reference quality factor value. At this time, the transmitter can determine a threshold value for FO detection based on the reference quality factor value. For example, the transmitter can use a predetermined threshold generation function with the reference quality factor value as a mediating variable to determine a threshold value or a threshold range for determining the presence or absence of foreign substances. Here, the threshold value or threshold range calculated by the threshold generation function is a value smaller than the reference quality factor value. In the negotiation stage 240, the transmitter can receive an FOD (Foreign Object Detection) status packet containing a reference quality factor value. At this time, the transmitter can determine a threshold value for FO detection based on the reference quality factor value. For example, the transmitter can use a predetermined threshold generation function with the reference quality factor value as a mediating variable to determine a threshold value or a threshold range for determining the presence or absence of foreign substances. Here, the threshold value or threshold range calculated by the threshold generation function is a value smaller than the reference quality factor value.

[0178] In the negotiation stage 240, the transmitter can receive an FOD (Foreign Object Detection) status packet containing a reference quality factor value. At this time, the transmitter can determine a threshold value for FO detection based on the reference quality factor value. For example, the transmitter can use a predetermined threshold generation function with the reference quality factor value as a mediating variable to determine a threshold value or a threshold range for determining the presence or absence of foreign substances. Here, the threshold value or threshold range calculated by the threshold generation function is a value smaller than the reference quality factor value. At this time, the transmitter can receive an FOD (Foreign Object Detection) status packet containing a reference quality factor value. At this time, the transmitter can determine a threshold value for FO detection based on the reference quality factor value. For example, the transmitter can use a predetermined threshold generation function with the reference quality factor value as a mediating variable to determine a threshold value or a threshold range for determining the presence or absence of foreign substances. Here, the threshold value or threshold range calculated by the threshold generation function is a value smaller than the reference quality factor value. Here, the threshold value or threshold range calculated by the threshold generation function is a value smaller than the reference quality factor value. The threshold value (FO_Threshold) for foreign substance detection according to the embodiment is the reference quality factor value (RQF_Value), a configuration factor (De sign_factor) preset according to the corresponding radio power transmitter, the tolerance defined by the standard, and the weighted value. Here, the weighted value can increase linearly or exponentially according to the reference quality factor value. That is, the threshold value for foreign substance detection is the following formula 1:

[0179] FO_Threshold=(RQF_Value*Design_factor)+ tolerance - weighted value (Equation 1)

[0180] and can be determined by

[0181] Generally, if a foreign substance is placed in the charging area, the quality factor value measured by the resonance circuit of the transmitter will decrease compared to before the foreign substance is placed. Actually, when a foreign substance is placed in the charging area in a wireless charging system, the ratio of the measured quality factor value to the reference quality factor value decreases. The ratio depends on the type of receiver placed in the charging area, that is, the reference quality factor value of the corresponding radio power receiver . In particular, the larger the reference quality factor value, the more sharply the reduction ratio of the quality factor value due to the placement of the foreign substance increases. Therefore, for a transmitter according to the present invention, when the radio power receiver has a large reference quality factor value, the ratio of the threshold value for foreign substance detection to the reference quality factor value can be determined so as to be low. As a result, the probability that the transmitter fails to detect a foreign substance can be reduced. The transmitter compares the quality factor value measured after object detection with the threshold value determined for FO detection and

[0182] ​ In comparison, it is possible to determine whether there is FO in the charging area, and power transmission can be controlled according to the FO detection result. As an example, when FO is detected, the transmitter can interrupt power transmission and output a predetermined warning alarm indicating that FO has been detected. When FO is detected, the transmitter can return to the selection stage 210. On the other hand, when FO is not detected, the transmitter can also enter the power transmission stage 260 through the correction stage 250. Specifically, when FO is not detected, the transmitter determines the intensity of the power received at the receiving end in the correction stage 250, and in order to determine the intensity of the power transmitted from the transmitting end, the power losses at the receiving end and the transmitting end can be measured. That is, the transmitter can predict the power loss based on the difference between the transmission power at the transmitting end and the received power at the receiving end in the correction stage 250. The transmitter according to one embodiment can also correct the threshold value for FOD detection by reflecting the predicted power loss. In the power transmission stage 260, when the transmitter receives an unexpected packet, or when the desired packet is not received within a predefined time (time out), or when a violation of the previously set power transmission contract occurs (power transfer contract violation), or when charging is completed, it can transition to the selection stage 210.

[0183] When FO is detected, the transmitter can return to the selection stage 210. On the other hand, when FO is not detected, the transmitter can enter the power transmission stage 260 after going through the correction stage 250. Specifically, when FO is not detected, the transmitter determines the intensity of the power received at the receiving end in the correction stage 250, and in order to determine the intensity of the power transmitted from the transmitting end, the power losses at the receiving end and the transmitting end can be measured. That is, the transmitter can predict the power loss based on the difference between the transmission power at the transmitting end and the received power at the receiving end in the correction stage 250. The transmitter according to one embodiment can also correct the threshold value for FOD detection by reflecting the predicted power loss. In the power transmission stage 260, when the transmitter receives an unexpected packet, or when the desired packet is not received within a predefined time (time out), or when a violation of the previously set power transmission contract occurs (power transfer contract violation), or when charging is completed, it can transition to the selection stage 210. Also, in the power transmission stage 260, due to changes in the state of the transmitter or the like, the transmitter can adjust the power transmission contract. The transmitter according to one embodiment can correct the threshold value for FOD detection by reflecting the predicted power loss.

[0184] In the power transmission stage 260, when the transmitter receives an unexpected packet, or when the desired packet is not received within a predefined time (time out), or when a violation of the previously set power transmission contract occurs (power transfer contract violation), or when charging is completed, it can transition to the selection stage 210. That is, when the transmitter receives an unexpected packet, or when the desired packet is not received within a predefined time (time out), or when a violation of the previously set power transmission contract occurs (power transfer contract violation), or when charging is completed, it can transition to the selection stage 210. When the transmitter receives an unexpected packet, or when the desired packet is not received within a predefined time (time out), or when a violation of the previously set power transmission contract occurs (power transfer contract violation), or when charging is completed, it can transition to the selection stage 210. When the transmitter receives an unexpected packet, or when the desired packet is not received within a predefined time (time out), or when a violation of the previously set power transmission contract occurs (power transfer contract violation), or when charging is completed, it can transition to the selection stage 210. When the transmitter receives an unexpected packet, or when the desired packet is not received within a predefined time (time out), or when a violation of the previously set power transmission contract occurs (power transfer contract violation), or when charging is completed, it can transition to the selection stage 210.

[0185] Also, in the power transmission stage 260, due to changes in the state of the transmitter or the like, the transmitter can adjust the power transmission contract. ​​If the agreement needs to be restructured, a transition to a renegotiation stage 270 can occur. If the renegotiation is successfully completed, the transmitter may revert to the power transfer stage 260 .

[0186] The power transfer agreement is set based on the status and characteristics information of the transmitter and receiver. As an 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.

[0187] FIG. 3 is a block diagram illustrating the structure of a wireless power receiver that operates in conjunction with a wireless power transmitter. be.

[0188] Referring to FIG. 3, the wireless power receiver 300 includes a receiving coil 310, a rectifier 320, a DC / DC / DC Converter 330, Load 340, Sensing Unit 3 50, a communication unit 360, and a main control unit 370. 0 can include at least one of a demodulation unit 361 and a modulation unit 362.

[0189] The wireless power receiver 300 shown in the example of FIG. 3 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 360 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.

[0190] The AC power received through the receiving coil 310 can be transmitted to the rectifier 320. The rectifier 320 converts AC power into DC power and transmits it to the DC / DC converter 330. is achievable. The DC / DC converter 330 can convert the intensity of the rectifier output DC power to a specific intensity required by the load 340 and then transmit it to the load 340. After conversion, it can be transmitted to the load 340.

[0191] The sensing unit 350 can measure the intensity of the rectifier 320 output DC power and provide it to the main control unit 37 0. Also, the sensing unit 350 can measure the intensity of the current applied to the receiving coil 310 by wireless power reception and transmit the measurement result to the main control unit 370 . Further, the sensing unit 350 can measure the internal temperature of the wireless power receiver 300 and also provide the measured temperature value to the main control unit 370. As an example, the main control unit 370 can compare the measured intensity of the rectifier output DC power with a predetermined reference value to determine whether overvoltage occurs. If overvoltage occurs as a result of the determination, a predetermined packet indicating the occurrence of overvoltage can be generated and transmitted to the modulation unit 362

[0192] . Here, the signal modulated by the modulation unit 362 can be transmitted to the wireless power transmitter 600 via the receiving coil 310 or another coil (not shown). Also, when the intensity of the rectifier output DC power is equal to or greater than a predetermined reference value, the main control unit 370 can determine that a sensing signal has been received, and at the time of receiving the sensing signal, control can be performed so that a signal strength indicator corresponding to the relevant sensing signal can be transmitted to the wireless power transmitter 600 via the modulation unit 362 . As another example, the demodulation unit 361 demodulates the AC power signal between the receiving coil 310 and the rectifier 320 or the rectifier 320 output DC power signal to identify whether a sensing signal can be received, and then can provide the identification result to the main control unit 370. At this time, the main control unit 370 senses the signal . Also, the main control unit 370 can control so that when the intensity of the rectifier output DC power is equal to or greater than a predetermined reference value, it can be determined that a sensing signal has been received, and at the time of receiving the sensing signal, a signal strength indicator corresponding to the relevant sensing signal can be transmitted to the wireless power transmitter 600 via the modulation unit 362 . When the intensity of the rectifier output DC power is equal to or greater than a predetermined reference value, the main control unit 370 can determine that a sensing signal has been received, and at the time of receiving the sensing signal, control can be performed so that a signal strength indicator corresponding to the relevant sensing signal can be transmitted to the wireless power transmitter 600 via the modulation unit 362 . Also, when the intensity of the rectifier output DC power is equal to or greater than a predetermined reference value, the main control unit 370 can determine that a sensing signal has been received, and at the time of receiving the sensing signal, control can be performed so that a signal strength indicator corresponding to the relevant sensing signal can be transmitted to the wireless power transmitter 600 via the modulation unit 362 . Also, when the intensity of the rectifier output DC power is equal to or greater than a predetermined reference value, the main control unit 370 can determine that a sensing signal has been received, and at the time of receiving the sensing signal, control can be performed so that a signal strength indicator corresponding to the relevant sensing signal can be transmitted to the wireless power transmitter 600 via the modulation unit 362 . As another example, the demodulation unit 361 demodulates the AC power signal between the receiving coil 310 and the rectifier 320 or the rectifier 320 output DC power signal to identify whether a sensing signal can be received, and then provides the identification result to the main control unit 370. At this time, the main control unit 370 can sense the signal . At this time, the main control unit 370 can sense the signal ​Control such that the signal strength indicator corresponding to the number can be transmitted via the modulation unit 362 can be done.

[0193] FIG. 4 is a diagram for explaining a packet format according to an embodiment of the present invention.

[0194] Referring to FIG. 4, used for information exchange between the wireless power transmitter 10 and the wireless power receiver 20 The packet format 400 includes a preamble 410 field for synchronization acquisition for demodulation of the corresponding packet and identification of the exact start bit of the corresponding packet , a header 420 field for identifying the type of message included in the corresponding packet , a message 430 field for transmitting the content (or payload) of the corresponding packet and a checksum 440 field for checking whether an error has occurred in the corresponding packet and can be made to include. The packet receiver can also identify the size of the message 430 included in the corresponding packet based on the header 420 value.

[0195] The header 420 can be defined for each stage of the wireless power transmission process, and some header 420 values can be defined to have the same value at different stages of the wireless power transmission process.

[0196] As an example, referring to FIG. 10, it should be noted that the header values corresponding to the end of power transfer in the ping stage (End Power Transfer) and the end of power transfer in the power transfer stage are 0x02 and are the same.

[0197] ​​​​Message 430 contains data to be transmitted from the transmitting end of the corresponding packet. As an example and the data included in the message 430 field can be reporting items (repo rt), request items (request), or response items (response) for the other party, but is not limited to this.

[0198] Packet 400 according to another embodiment of the present invention may further include at least one of transmission end identification information for identifying the transmission end that transmitted the corresponding packet and reception end identification information for identifying the reception end that receives the corresponding packet. Here, the transmission end identification information and the reception end identification information can include IP address information, MAC address information, product identification information, etc., but is not limited to this, and information that can distinguish the reception end and the transmission end on the wireless charging system is sufficient.

[0199] Packet 400 according to still another embodiment of the present invention may further include predetermined group identification information for identifying the corresponding reception group when the corresponding packet must be received by a plurality of devices.

[0200] FIG. 5 is a diagram for explaining the types of packets transmitted from a wireless power receiver to a wireless power transmitter according to an embodiment of the present invention.

[0201] Referring to FIG. 5, the packets transmitted from the wireless power receiver to the wireless power transmitter include Signal Strength (Signal Strength ) packets for transmitting the intensity information of the sensed ping signal, End Power Transfer for requesting the transmitter to interrupt power transmission, and after receiving the control error packet for control, actually the electricity ) ​​​​​​​​Power Control Hold-off packets for transmitting time information to wait until the force is adjusted, configuration packets for transmitting the configuration information of the receiver, identification packets and extended identification packets for transmitting receiver identification information, general request packets for transmitting general request messages, special request packets for transmitting special request messages, FOD status packets for transmitting reference quality factor values for FO detection, control error packets for controlling the transmission power of the transmitter, renegotiation packets for starting renegotiation, 24-bit received power packets and 8-bit received power packets for transmitting the intensity information of the received power, and charge state packets for transmitting the charge state information of the current load can be included. trol Hold-off) packets, configuration packets for transmitting the configuration information of the receiver, identification packets and extended identification packets for transmitting receiver identification information, general request packets for transmitting general request messages, special request packets for transmitting special request messages, FOD status packets for transmitting reference quality factor values for FO detection, control error packets for controlling the transmission power of the transmitter, renegotiation packets for starting renegotiation, 24-bit received power packets and 8-bit received power packets for transmitting the intensity information of the received power, and charge state packets for transmitting the charge state information of the current load can be included. FOD status packets for transmitting reference quality factor values for FO detection, control error packets for controlling the transmission power of the transmitter, renegotiation packets for starting renegotiation, 24-bit received power packets and 8-bit received power packets for transmitting the intensity information of the received power, and charge state packets for transmitting the charge state information of the current load can be included. control error packets for controlling the transmission power of the transmitter, renegotiation packets for starting renegotiation, 24-bit received power packets and 8-bit received power packets for transmitting the intensity information of the received power, and charge state packets for transmitting the charge state information of the current load can be included. renegotiation packets for starting renegotiation, 24-bit received power packets and 8-bit received power packets for transmitting the intensity information of the received power, and charge state packets for transmitting the charge state information of the current load can be included. 24-bit received power packets and 8-bit received power packets for transmitting the intensity information of the received power, and charge state packets for transmitting the charge state information of the current load can be included. can be included.

[0202] The packets transmitted from the aforementioned wireless power receiver to the wireless power transmitter can be transmitted using in-band communication using the same frequency band as the frequency band used for wireless power transmission. using the same frequency band as the frequency band used for wireless power transmission.

[0203] FIG. 6a is a block diagram for explaining the structure of a foreign substance detection device according to an embodiment of the present invention. is.

[0204] Referring to FIG. 6a, the foreign substance detection device 600 can include a power supply unit 601, a DC / DC converter (D C-DC Converter) 610, an inverter 620, a resonant circuit 630, a measurement unit 640, a communication unit 660, a sensing unit 670, and a control unit 680. The foreign substance detection device 600 according to this embodiment can be mounted on a wireless power transmission device. The foreign substance detection device 600 according to this embodiment can be mounted on a wireless power transmission device. can be mounted.

[0205] The resonant circuit 630 includes a resonant capacitor 631 and a resonant inductor 632, The communication unit 660 can include at least one of a demodulation unit 661 and a modulation unit 662 .

[0206] The power supply unit 601 can receive DC power applied via an external power supply terminal and transmit it to a DC / DC converter 61 0

[0207] The DC / DC converter 610 can convert the intensity of the DC power input from the power supply unit 601 under the control of the control unit 680 into DC power of a specific intensity. As an example, the DC / DC converter 610 can be composed of a variable voltage regulator capable of adjusting the voltage intensity, but is not limited to this .

[0208] The inverter 620 can convert the converted DC power into AC power. The inverter 620 can convert the input DC power signal into an AC power signal by means of the control of a plurality of provided switches and output it

[0209] As an example, the inverter 620 can include a full bridge circuit , but is not limited to this, and can also include a half bridge e

[0210] As another example, the inverter 620 can also include both a half bridge circuit and a full bridge circuit . In this case, the control unit 680 can dynamically determine whether to operate the inverter 620 as a half bridge or as a full bridge and perform control .

[0211] The wireless power transmission device according to an embodiment of the present invention is the power required by the wireless power reception device The bridge mode of the inverter 620 can be adaptively controlled according to the strength of the force. . Here, the bridge mode includes a half-bridge mode and a full-bridge mode.

[0212] As an example, when the wireless power receiving device requires low power of 5W, the control unit 680 can control the inverter 620 to operate in the half-bridge mode. On the other hand, when the wireless power receiving device requires power of 15W, the control unit 680 can control it to operate in the full-bridge mode. - ter 620 to operate in the half-bridge mode. On the other hand, when the wireless power receiving device requires power of 15W, the control unit 680 can control it to operate in the full-bridge mode.

[0213] As another example, the wireless power transmitting device can also adaptively determine the bridge mode according to the sensed temperature and drive the inverter 620 according to the determined bridge mode. As an example, when the temperature of the wireless power transmitting device exceeds a predetermined reference value while transmitting wireless power in the half-bridge mode, the control unit 680 can control to deactivate the half-bridge mode and activate the full-bridge mode. That is, the wireless power transmitting device can increase the voltage through the full-bridge circuit and decrease the intensity of the current flowing through the resonance circuit 630 for transmitting the same intensity of power, so as to control the internal temperature of the wireless power transmitting device to be maintained below the predetermined reference value. power transmitting device When the temperature exceeds a predetermined reference value, the control unit 680 can control to deactivate the half-bridge mode and activate the full-bridge mode. That is, the wireless power transmitting device can increase the voltage through the full-bridge circuit and decrease the intensity of the current flowing through the resonance circuit 630 for transmitting the same intensity of power, so as to control the internal temperature of the wireless power transmitting device to be maintained below the predetermined reference value. power transmitting device can increase the voltage through the full-bridge circuit and decrease the intensity of the current flowing through the resonance circuit 630 for transmitting the same intensity of power, so as to control the internal temperature of the wireless power transmitting device to be maintained below the predetermined reference value. power transmitting device can increase the voltage through the full-bridge circuit and decrease the intensity of the current flowing through the resonance circuit 630 for transmitting the same intensity of power, so as to control the internal temperature of the wireless power transmitting device to be maintained below the predetermined reference value.

[0214] Generally, the amount of heat generated by the electronic components mounted on the electronic device may be more sensitive to the intensity of the current than to the intensity of the voltage applied to the corresponding electronic components.

[0215] In addition, the inverter 620 can not only convert DC power into AC power, [[ID=4l]] but also change the intensity of the AC power.

[0216] As an example, the inverter 620 can also adjust the intensity of the output AC power by adjusting the frequency of a reference alternating current signal (Reference Alternating Current Signal) used for generating the AC power under the control of the control unit 680. Signal). For this purpose, the inverter 620 can include a frequency oscillator that generates a reference alternating current signal having a specific frequency, but this is only one embodiment, and in other examples, the frequency oscillator can be configured separately from the inverter 620 and mounted on one side of the foreign substance detection device 600.

[0217] As another example, the foreign substance detection device 600 can further include a gate driver (not shown) for controlling the switch provided in the inverter 620. In this case, the gate driver can receive at least one pulse width modulation signal from the control unit 680, and can control the switch of the inverter 620 by the received pulse width modulation signal. The control unit 680 can control the duty cycle (Duty Cycle), that is, the duty rate (Duty Rate), and the phase of the pulse width modulation signal to control the intensity of the output power of the inverter 620. The control unit 680 can adaptively control the duty cycle and phase of the pulse width modulation signal based on the feedback signal received from the wireless power receiving device.

[0218] The measuring unit 640 measures at least one of the voltage, current, and impedance at both ends of the resonance capacitor 631 under the control signal of the control unit 680 to measure the quality factor for the resonance circuit 630. ​​​​​​​​​​​​​​​The value and / or inductance value can be calculated. At this time, the calculated quality factor The value and / or inductance value is transmitted to the control unit 680, and the control unit 680 temporarily stores the quality factor value and / or inductance value transmitted from the measurement unit 640 in a predetermined recording area This can also be done. As an example, if an object is sensed on the charging area in the selection stage the control unit 680 can control the measurement unit 640 to calculate the quality factor value and / or inductance value before entering the ping stage

[0219] If the control unit 680 receives an FOD status packet from the modulation unit 662 in the negotiation stage, it can determine a threshold value ( or threshold range) for determining the presence or absence of a foreign substance based on the information included in the FOD status packet

[0220] The threshold value (FO_Threshold) for foreign substance detection according to an embodiment is based on a reference quality factor value (RQF_Value), a configuration factor ( Design_factor) preset corresponding to the corresponding radio power transmitter, a tolerance defined by the standard, and a weighting value. Here, the weighting value can increase linearly or exponentially according to the reference quality factor value. That is, the control unit 680 uses the following formula 1:

[0221] FO_Threshold = (RQF_Value * Design_factor) + tolerance - weighting value (Formula 1)

[0222] to determine the threshold value for foreign substance detection

[0223] As an example, the weighting value is calculated by a predetermined linear function using the reference quality factor value as a mediating variable ​​​​​Although it can be calculated by this, it is not limited to this and can be calculated by a second-order or higher-order function. It can also be done.

[0224] As another example, the weighting values are predefined for each type of wireless power receiver and are recorded and maintained in a predetermined recording area of the foreign object detection device 60, for example, in a non-volatile memory. Here, the weighting values for each type of wireless power receiver can be maintained in the form of a mapping table. However, it is not limited to this.

[0225] The critical range for foreign object detection according to other embodiments is identified by an upper critical value (FO_Threshold _Upper_Limit) and a lower critical value (FO_Threshold_Lower_Li mit), and is determined based on a reference quality factor value (RQF_Value), a configuration factor (Design_factor) preset according to the corresponding wireless power transmitter, a tolerance defined by a standard, an upper weighting value, and a lower weighting value. Here, the upper weighting value and the lower weighting value can increase linearly or exponentially according to the reference quality factor value. That is, the control unit 680 uses the following formula 2: FO_Threshold_Upper_Limit=(RQF_Value*Des ign_factor)+tolerance - upper weighting value

[0226] ign_factor)+tolerance - upper weighting value

[0227] FO_Threshold_Lower_Limit=(RQF_Value*Des ign_factor)+tolerance - lower weighting value (Formula 2)

[0228] to determine the critical range for foreign object detection. The control unit 680 measures ​​When the obtained quality factor value is between the upper critical value and the lower critical value, it is determined that a foreign substance is present. This can be done.

[0229] The critical value (FO_Threshold) for foreign substance detection according to another embodiment of the present invention is , as shown in Table 1 below, can also be determined by applying a ratio proportionally according to the magnitude of the reference quality factor (RQF) value. This can be determined by applying a ratio proportionally according to the magnitude of the reference quality factor (RQF) value.

[0230] As an example, referring to Table 1 below, if the reference quality factor (RQF) value exceeds 80, the differential ratio (Diff Ratio) is applied as 40%, and the critical value (FO_Threshold) for foreign substance detection at this time can be calculated by RQFx0.66 + tolerance. the differential ratio (Diff Ratio) is applied as 40%, and the critical value (FO_Threshold) for foreign substance detection at this time can be calculated by RQFx0.66 + tolerance. This can be calculated by RQFx0.66 + tolerance.

[0231] As another example, referring to Table 1 below, when the reference quality factor (RQF) value is greater than 50 and less than or equal to 60, the differential ratio (Diff Ratio) is applied as 10%, and the critical value (FO_Threshold) for foreign substance detection at this time can be calculated by RQFx0.69 + tolerance. and less than or equal to 60, the differential ratio (Diff Ratio) is applied as 10%, and the critical value (FO_Threshold) for foreign substance detection at this time can be calculated by RQFx0.69 + tolerance. This can be calculated by RQFx0.69 + tolerance.

[0232]

Table 1

[0233] The wireless power transmitter receives the reference quality factor value via the FOD status packet in the negotiation stage, and can adaptively determine the FO_Threshold according to the received reference quality factor value. The larger the RQF value shown in Table 1 above, the difference value between the RQF value and the FO_Threshold increases according to the differential ratio corresponding to the relevant RQF value. On the other hand, when the RQF value is small increases according to the differential ratio corresponding to the relevant RQF value. On the other hand, when the RQF value is small Thus, the difference value between the RQF value and the FO_Threshold decreases according to the corresponding difference ratio for the RQF value. Table 1 above is only an example, and the difference ratio based on the RQF value can also be determined to vary depending on the design of those skilled in the art and the configuration of the device. It should be noted.

[0234] Generally, if a foreign substance is placed in the charging area, the quality factor value measured by the resonance circuit of the transmitter will decrease compared to before the foreign substance is placed. In an actual wireless charging system, when a foreign substance is placed in the charging area, the ratio at which the measured quality factor value decreases with respect to the reference quality factor value varies depending on the type of the receiver placed in the charging area, that is, depending on the reference quality factor value of the corresponding wireless power receiver.

[0235] In particular, the larger the reference quality factor value, the more rapidly the ratio of the decrease in the quality factor value due to the placement of the foreign substance increases. Therefore, when the control unit 680 according to the present invention is a wireless power receiver with a large reference quality factor value, it can determine the critical value (or critical range) so that the ratio of the critical value for detecting a foreign substance with respect to the reference quality factor value is low. As a result, the probability that the transmitter fails to detect a foreign substance can be reduced.

[0236] The control unit 680 can compare the quality factor value measured after detecting an object with the critical value determined for FO detection to determine whether there is an FO in the charging area, and can control power transmission according to the FO detection result.

[0237] As an example, when an FO is detected, the control unit 680 can interrupt power transmission. Control to output a predetermined warning alarm indicating that FO has been detected is possible. Here, the warning alarm can be output via at least one of a beeper, an LED lamp , a vibration element, and a liquid crystal display provided in the foreign substance detection device 600, but is not limited thereto.

[0238] As an example, when the quality factor value measured after object sensing in the selection stage and before entering the ping stage is smaller than a determined threshold value, the control unit 680 can determine that there is a foreign substance in the charging area.

[0239] As another example, when the quality factor value measured after object sensing in the selection stage and before entering the ping stage is included in a determined critical range, the control unit 680 can also determine that there is a foreign substance in the charging area.

[0240] The reference quality factor value included in the FOD status packet can be determined as the minimum value among the quality factor values calculated corresponding to the wireless power receiver at a specific position of the charging bed of the wireless power transmitter specified for the standard performance test.

[0241] Also, if a foreign substance is sensed in the negotiation stage, the control unit 680 can return to the selection stage and control the measurement unit 640 to calculate the quality factor value of the resonance circuit 630 at a predetermined cycle.

[0242] At this time, the control unit 680 can compare the quality factor value obtained in the state where a foreign substance is sensed with a previously determined threshold value (or critical range) to determine whether the previously sensed foreign substance has been removed from the charging area.

[0243] ​​​​​​​​​​As an example, when the quality factor value measured in a state where a foreign substance is detected is already greater than a determined critical value, it can be determined that the foreign substance has been removed. In another example as well, when the quality factor value measured in a state where a foreign substance is detected exceeds an upper critical value , it can also be determined that the foreign substance has been removed.

[0244] In addition, the control unit 680 can also adaptively determine a critical value for foreign substance detection by referring to Table 1 described above (hereinafter referred to as the 'critical value determination table' for the convenience of explanation). The critical value determination table can be maintained in a predetermined recording area of a memory (not shown) provided in the foreign substance detection device 680. When a FOD

[0245] state packet including a reference quality factor value is received during the negotiation stage, the control unit 680 refers to the received reference quality factor value and the critical value determination table to determine a critical value for foreign substance detection, and compares the determined critical value with the already measured quality factor value to determine the presence or absence of a foreign substance. Here, the critical value determination table can be updated. As an example, the foreign substance detection device can be connected to a specific server via a wired or wireless network and update the critical value determination table in conjunction with the corresponding server. As another example, the foreign substance detection

[0246] device can also receive or update the critical value determination table from a connected wireless power receiver. The foreign substance detection device can be connected to a specific server via a wired or wireless network and update the critical value determination table in conjunction with the corresponding server. As another example, the foreign substance detection device can also receive or update the critical value determination table from a connected wireless power receiver. The critical value determination table can be generated according to the type of the wireless power receiver, and the foreign substance detection device can refer to the critical value determination table corresponding to the identified type of the wireless power receiver to detect foreign substances.

[0247] The critical value determination table can be generated for each type of wireless power receiver, and the foreign substance detection device can refer to the critical value determination table corresponding to the identified type of the wireless power receiver to detect foreign substances. It is also possible to determine a threshold value for foreign object detection.

[0248] The wireless power receiver according to one embodiment may maintain a threshold value determination table for each type of wireless power transmitter. In this case, the wireless power receiver can also transmit the corresponding threshold value determination table to the corresponding wireless power transmitter for the identified type of wireless power transmitter. The wireless power transmitter can determine a threshold value for foreign object detection based on the received threshold value determination table.

[0249] As described above, the foreign object detection device according to an embodiment of the present invention can adaptively determine a threshold value for foreign object detection with reference to a threshold value determination table corresponding to the type of the wireless power receiver or (and) the type of the wireless power transmitter.

[0250] If the determination result is that the foreign object has been removed, the control unit 680 can re-enter the power transmission stage and control to resume charging the corresponding wireless power receiving device.

[0251] In addition, the threshold value can include an inductance threshold value and a quality factor threshold value. If the determined value is within the critical range, the critical range can include an inductance critical range and a quality factor critical range. It is also possible to use the two threshold values together to detect foreign objects, and determine the corresponding threshold value for the corresponding type according to the type of the reference value transmitted by each receiver to detect foreign objects.

[0252] Here, the FOD status packet may include a reference quality factor value or (and) a reference inductance value corresponding to the corresponding wireless power receiver. The control unit 680 receives the received reference quality Quality factor for determining the presence or absence of foreign substances based on the quality factor value and the reference inductance value A critical value and / or an inductance critical value can be determined. As an example, the reference quality factor value and a value corresponding to 90% of the reference inductance value can be determined as the quality factor critical value and / or the inductance critical value, but it is not limited thereto, and the ratio can be defined differently by those skilled in the art design.

[0253] As an example, if the quality factor value (measured before the ping stage) already stored in the control unit 680 is smaller than the determined quality factor critical value or the inductance value already stored is smaller than the determined inductance critical value, it can be determined that a foreign substance is present

[0254] When it is determined that a foreign substance is present, the control unit 680 can control to interrupt power transmission and output a predetermined warning alarm indicating that the foreign substance has been detected. As an example, the notification means can include, but is not limited to, a beeper, an LED lamp, a vibration element, a liquid crystal display, etc

[0255] The reference quality factor value included in the FOD status packet is determined to be the minimum value among the quality factor values calculated corresponding to the corresponding wireless power receiver at a specific position of the charging bed of the specified wireless power transmitter

[0256] The inductance value included in the FOD status packet is determined to be the minimum value among the inductance values calculated corresponding to the corresponding wireless power receiver at a specific position of the charging bed of the wireless power transmitter specified for the standard performance test

[0257] ​​​​​​​​​​​ Also, if a foreign substance is detected during the negotiation stage, the control unit 680 returns to the selection stage and controls the measurement unit 640 to calculate the quality factor value and inductance value of the resonance circuit 630 at a predetermined period. At this time, the control unit 680 can compare the quality factor value and inductance value obtained in the state where the foreign substance is detected with the already determined quality factor critical value and inductance critical value respectively, and determine whether the already detected foreign substance has been removed from the charging area. As an additional example, if the determination result is that the foreign substance has been removed, the control unit 6 80 can enter the power transmission stage and control to resume charging the corresponding wireless power receiving device. At this time, it can enter the power transmission stage by skipping the identification and setting stage and / or the negotiation stage.

[0258] The demodulation unit 661 demodulates the in-band signal received from the wireless power receiving device and transmits it to the control unit 680. As an example, the demodulation unit 661 can demodulate the packet described in FIG. 10 above and transmit it to the control unit 680.

[0259] The sensing unit 670 can measure the voltage, current, power, impedance, temperature, etc. at a specific terminal, specific element, specific position, etc. of the foreign substance detection device 600 (or the wireless power transmission device).

[0260] As an example, the sensing unit 670 can measure the voltage / current of the DC-converted power and provide it to the control unit 680. Also, the sensing unit 670 can measure the internal temperature of the wireless power transmission device for determining the presence or absence of overheating, and provide the measurement result to the control unit 680. In this case, the control unit 680 can use the voltage / current measured by the sensing unit 670. ​​​​​​​​​​​ adaptively cut off the power supply from the power source based on the value, or cut off the power supply to the resonant circuit 630. For this purpose, on one side of the foreign substance detection device 600, a predetermined power cut-off circuit for cutting off the power supply supplied from the power supply unit 601 or the DC power supplied to the inverter 620 can be further provided. It can be interrupted. from being supplied.

[0261] The sensing unit 670 can further include a Hall sensor, a pressure sensor, etc. In this case, whether an object exists in the charging area can be sensed by a Hall sensor, a pressure sensor, etc., but it is not limited to this.

[0262] While the sensing unit 670 is transmitting an analog ping signal in the selection stage, it can sense changes in the current, voltage, impedance, etc. of the resonant circuit 630 to sense whether an object exists in the charging area.

[0263] As described above, when an object is sensed in the selection stage, the foreign substance detection device 600 according to the present invention measures (or calculates) the quality factor value of the resonant circuit before entering the ping stage, and compares the measured quality factor value with the critical value (or critical range) determined in the negotiation stage to determine the presence or absence of foreign substances. By doing so, the probability of failure in foreign substance detection can be significantly reduced. There is an advantage.

[0264] The sensing unit can be replaced by a measuring unit and omitted.

[0265] In addition, the foreign substance detection device 600 according to the present invention dynamically determines the critical value (or critical range) for foreign substance detection by the reference quality factor value corresponding to the corresponding wireless power receiver. ​​​​​​​​, it is possible to perform foreign object detection optimized for the corresponding wireless power receiver.

[0266] The detailed operation of the remaining components shown in FIG. 6b is described in the description of FIG. 6a above and is replaced. Replaced.

[0267] FIG. 7a is a diagram for explaining the message structure of a foreign object detection status packet according to an embodiment of the present invention. ct Detection Status Packet). It is a figure for.

[0268] Referring to FIG. 7a, the FOD status packet message 700 can have a length of 2 bytes, a 6-bit length reserved 701 field, a 2-bit length mode 702 field, and a 1-byte length reference quality factor value 703 field. It can consist of. Here, the total bits of the reserved 701 field are recorded as 0. It can, and a reserved 701 field of 6-bit length, a mode 702 field of 2-bit length, and a reference quality factor value 703 field of 1-byte length. ence Quality Factor Value) 703 field. It can consist of. Here, the total bits of the reserved 701 field are recorded as 0. It can. Here, the total bits of the reserved 701 field are recorded as 0.

[0269] As shown by the reference numeral 704, if the mode 702 field is set to the binary number '00', it can mean that the reference quality factor value determined by measuring the power supply of the corresponding wireless power receiver in the OFF state is recorded in the reference quality factor value 703 field. When the power supply of the corresponding wireless power receiver is OFF, it can mean that the reference quality factor value determined by measurement is recorded in the reference quality factor value 703 field. It can mean that the reference quality factor value determined by measurement is recorded in the reference quality factor value 703 field.

[0270] FIG. 7b is a diagram for explaining the message structure of the FOD status packet according to an embodiment of the present invention. It is a figure for.

[0271] Referring to FIG. 7b, the FOD status packet message 700 can have a length of 2 bytes, a first data 701 field of 6-bit length, a mode (Mo of 2-bit length, and a mode of 2-bit length. It can, and a first data 701 field of 6-bit length, a mode (Mo of 2-bit length, and a mode of 2-bit length. (de) It can include a 702 field and a reference quality factor value (Reference Qu ality Factor Value) 703 field.

[0272] As shown by the drawing reference numeral 704, if the mode 702 field is set to the binary number '00' then the total bits of the first data 701 field are recorded as 0, and the reference quality factor value determined by measurement in a state where the power supply of the corresponding radio power receiver is OFF is recorded in the reference quality factor value 703 field. On the other hand, if the mode 702 field is set to the binary number '01' then the reference inductance value determined by measurement in a state where the power supply of the corresponding radio power receiver is OFF is recorded in the first data 701 field, and the reference quality factor value determined by measurement in a state where the power supply of the corresponding radio power receiver is OFF is recorded in the reference quality factor value 703 field. In this embodiment, the foreign substance detection device (or radio power transmission device) can obtain at least one of the reference quality factor value and the reference inductance value corresponding to the corresponding radio power receiver at the negotiation stage.

[0273] In this embodiment, the foreign substance detection device (or radio power transmission device) can obtain at least one of the reference quality factor value and the reference inductance value corresponding to the corresponding radio power receiver at the negotiation stage.

[0274] Fig. 7c is a diagram for explaining the message structure of the FOD state packet according to another embodiment of the present invention.

[0275] Referring to Fig. 7c, the FOD state packet message 700 can have a length of 2 bytes, and can include a 6-bit length reserved (Reserved) 701 field, a 2-bit length mode (Mode) 702 field and a 1-byte length reference value (Reference Value) 703 field. Here, the reserved 701 field ​ The total bits of Rud are recorded as '0'.

[0276] As shown by the drawing reference numeral 704, if the mode 702 field is set to the binary number '00', the reference quality factor value measured and determined in the state where the power supply of the corresponding wireless power receiver is OFF is recorded in the reference value 703 field. On the other hand, if the mode 702 field is set to the binary number '01', the reference inductance value measured and determined in the state where the power supply of the corresponding wireless power receiver is OFF is recorded in the reference value 703 field. '01', the reference inductance value measured and determined in the state where the power supply of the corresponding wireless power receiver is OFF is recorded in the reference value 703 field. '01', the reference inductance value measured and determined in the state where the power supply of the corresponding wireless power receiver is OFF is recorded in the reference value 703 field.

[0277] In this embodiment, the foreign substance detection device (or the wireless power transmission device) can obtain at least one of the reference quality factor value and the reference inductance value corresponding to the corresponding wireless power receiver in the negotiation stage. In this embodiment, the foreign substance detection device (or the wireless power transmission device) can obtain at least one of the reference quality factor value and the reference inductance value corresponding to the corresponding wireless power receiver in the negotiation stage. In this embodiment, the foreign substance detection device (or the wireless power transmission device) can obtain at least one of the reference quality factor value and the reference inductance value corresponding to the corresponding wireless power receiver in the negotiation stage.

[0278] FIG. 8a is a diagram for explaining a state transition process for foreign substance detection in a foreign substance detection device according to an embodiment of the present invention. FIG. 8a is a diagram for explaining a state transition process for foreign substance detection in a foreign substance detection device according to an embodiment of the present invention.

[0279] Referring to FIG. 8a, if an object is sensed in the selection stage 810, the foreign substance detection device can enter the ping stage 820 after measuring and storing the quality factor value of the resonance circuit. In the ping stage 820, the foreign substance detection device can periodically transmit a predetermined power signal for identifying the wireless power receiver, Referring to FIG. 8a, if an object is sensed in the selection stage 810, the foreign substance detection device can enter the ping stage 820 after measuring and storing the quality factor value of the resonance circuit. In the ping stage 820, the foreign substance detection device can periodically transmit a predetermined power signal for identifying the wireless power receiver, Referring to FIG. 8a, if an object is sensed in the selection stage 810, the foreign substance detection device can enter the ping stage 820 after measuring and storing the quality factor value of the resonance circuit. In the ping stage 820, the foreign substance detection device can periodically transmit a predetermined power signal for identifying the wireless power receiver, for example, a digital ping.

[0280] If the foreign substance detection device receives a signal strength indicator corresponding to the digital ping in the ping stage 820, it can enter the identification and configuration stage 830 to identify the wireless power receiver and set various configuration parameters for the identified wireless power receiver. If the foreign substance detection device receives a signal strength indicator corresponding to the digital ping in the ping stage 820, it can enter the identification and configuration stage 830 to identify the wireless power receiver and set various configuration parameters for the identified wireless power receiver. If the foreign substance detection device receives a signal strength indicator corresponding to the digital ping in the ping stage 820, it can enter the identification and configuration stage 830 to identify the wireless power receiver and set various configuration parameters for the identified wireless power receiver.

[0281] Once the identification and configuration of the wireless power receiver are completed, the foreign object detection device enters negotiation stage 840 and can receive an FOD status packet containing a reference quality factor value.

[0282] Based on the reference quality factor value included in the FOD status packet, the foreign object detection device determines a threshold value (or threshold range) for determining the presence or absence of a foreign object, and compares the stored quality factor value with the determined threshold value (or threshold range) to determine whether a foreign object is present in the charging area. and can make a determination.

[0283] As described with reference to FIG. 6a, when the wireless power receiver has a low reference quality factor value, if a foreign object is placed in the charging area, the quality factor value for the corresponding reference quality factor value is relatively small or low compared to a wireless power receiver with a large magnitude and ratio of decrease. Therefore, the foreign object detection device according to an embodiment of the present invention can adaptively determine a threshold value (or threshold range) for foreign object detection based on the reference quality factor value received from the wireless power receiver.

[0284] If the determination result indicates the presence of a foreign object, the foreign object detection device can interrupt power transmission and return to the selection stage 810. On the other hand, if the determination result indicates the absence of a foreign object, the foreign object detection device can enter the power transmission stage 850 and start wireless charging for the corresponding wireless power receiver.

[0285] FIG. 8b is a diagram for explaining a state transition process for foreign object detection in a foreign object detection device according to an embodiment of the present invention.

[0286] Referring to FIG. 8b, if an object is sensed at the selection stage 810, the foreign object detection device resonates ​After measuring and storing the quality factor value and inductance value of the circuit, enter the ping stage 820 It can. In the ping stage 820, the foreign object detection device can periodically transmit a predetermined power signal for identifying the wireless power receiver, such as a digital ping.

[0287] If the signal strength indicator is received in the ping stage 820, the foreign object detection device enters the identification and configuration stage 830 to identify the wireless power receiver and can set various configuration parameters for the identified wireless power receiver.

[0288] Once the identification and configuration of the wireless power receiver are completed, the foreign object detection device enters the negotiation stage 840 and can receive an FOD status packet containing a reference quality factor value or (and) a reference inductance value.

[0289] Based on the reference value (etc.) contained in the FOD status packet, the foreign object detection device determines a threshold value (or threshold range) for judging the presence or absence of a foreign object and can judge whether there is a foreign object in the charging area based on the determined threshold value (or threshold range).

[0290] If the judgment result is that there is a foreign object, the foreign object detection device can interrupt the power transmission and return to the selection stage 810. On the other hand, if the judgment result is that there is no foreign object, the foreign object detection device enters the power transmission stage 850 and can start wireless charging for the corresponding wireless power receiver. Before entering the power transmission stage 850, the foreign object detection device can also perform the correction stage 250 as described in FIG. 2 above.

[0291] FIG. 9a illustrates a foreign object sensing method in a wireless power transmission device according to another embodiment of the present invention. is a flowchart for the eyes.

[0292] Referring to FIG. 9a, if an object is sensed on the charging area in the selection stage, the quality factor value of the resonant circuit can be measured and stored in a predetermined recording area (S901). .

[0293] The wireless power transmitter can check whether a foreign substance has been sensed previously. (S902).

[0294] If the result of the check shows that no foreign substance has been sensed, the wireless power transmitter enters the ping stage and can wirelessly send a digital ping signal for identifying the wireless power receiver. (S903). If the wireless power transmitter receives a signal strength indicator corresponding to the digital ping signal, it enters the identification and configuration stage. Once the identification and configuration of the wireless power receiver are completed, it can transition to the negotiation stage.

[0295] (S904). Based on the reference quality factor value included in the FOD status packet received in the negotiation stage, the wireless power transmitter can determine a threshold value (or threshold range) for determining the presence or absence of a foreign substance. (S905). Here, the method for determining the threshold value and threshold range is replaced by the description in FIGS. 11 to 13 above. The wireless power transmitter can wirelessly send a power signal of a predetermined intensity in the negotiation stage.

[0296] The wireless power transmitter can compare the stored quality factor value with the determined threshold value (or threshold range) to determine whether a foreign substance is present on the charging area. (S906).

[0297]

[0298] ​​​​​ If a foreign object is detected as a result of the determination, the wireless power transmitter can control to interrupt the power signal transmission and output a predetermined warning alarm indicating that a foreign object has been detected (S907~S908). After that, the wireless power transmitter can return to the above-described step 901 . .

[0299] If no foreign object is detected as a result of the determination in step 906 described above, the wireless power transmitter can enter the power transmission stage and start charging the corresponding wireless power receiver (S909) .

[0300] If it is confirmed in step 902 described above that a foreign object has already been detected, the wireless power transmitter can determine whether the detected foreign object has been removed from the charging area (S910) . Here, the method for determining whether the detected foreign object has been removed from the charging area is replaced by the description of FIGS. 6a to 8b described above . .

[0301] If it is determined that the detected foreign object has been removed, the wireless power transmitter can enter the power transmission stage and resume charging the corresponding wireless power receiver .

[0302] If it is determined in step 910 described above that the detected foreign object has not been removed, the wireless power transmitter can perform the above-described step 901 .

[0303] FIG. 9b is a flowchart for explaining a foreign object sensing method in a wireless power transmitter according to another embodiment of the present invention .

[0304] Referring to FIG. 9b, if an object is detected on the charging area at the selection stage, the wireless power transmitter Then, the quality factor value and / or inductance value of the resonant circuit are measured and stored in a predetermined recording area. This can be done (S901).

[0305] The wireless power transmitter can check whether a foreign object is detected (S90 2).

[0306] If the confirmation result shows that no foreign object is detected, the wireless power transmitter proceeds to the ping stage and can wirelessly send a digital ping signal for identifying the wireless power receiver (S903). This can be done (S903).

[0307] If the wireless power transmitter receives a signal strength indicator corresponding to the digital ping signal, it enters the identification and configuration stage. If the identification and configuration of the wireless power receiver are completed, it can transition to the negotiation stage (S904).

[0308] The wireless power transmitter can determine a threshold value (or threshold range) for judging the presence or absence of a foreign object based on the FOD status packet received in the negotiation stage (S905). Here, the threshold value can include an inductance threshold value and a quality factor threshold value. If the determined value is within the threshold range, the threshold range can include an inductance threshold range and a quality factor threshold range. The wireless power transmitter can wirelessly send a power signal of a predetermined intensity in the negotiation stage. This can be done. The wireless power transmitter can wirelessly send a power signal of a predetermined intensity in the negotiation stage. This can be done.

[0309] The wireless power transmitter compares the stored measurement value with the determined threshold value (or threshold range) to judge whether a foreign object exists on the charging area (S906).

[0310] If the judgment result shows that a foreign object exists, the wireless power transmitter interrupts the power signal transmission and the foreign object It can be controlled to output a predetermined warning alarm indicating that it has been detected. (Optional) (S907~S908). After that, the wireless power transmitter can return to the 901 steps described above.

[0311] Based on the determination result of the 906 steps described above, if no foreign substance is present, the wireless power transmitter can enter the power transmission step and start charging the corresponding wireless power receiver (S909). .

[0312] Based on the confirmation result of the 902 steps described above, if a foreign substance has already been detected, the wireless power transmitter can determine whether the detected foreign substance has been removed from the charging area (S910). Here, whether the detected foreign substance has been removed from the charging area can be determined by comparing the quality factor value and inductance value of the resonance circuit measured in the 901 step with the critical value ( or critical range) determined in the 905 step, but it is not limited thereto.

[0313] If the determination result is that the detected foreign substance has been removed, the wireless power transmitter can enter the power transmission step and resume charging the corresponding wireless power receiver.

[0314] Based on the determination result of the 910 steps described above, if the detected foreign substance has not been removed, the wireless power transmitter can perform the 901 steps described above.

[0315] As described above, the wireless power transmitter according to the present invention measures (or calculates) the quality factor value and inductance value of the resonance circuit before entering the ping step if an object is detected in the selection step, and compares the measured values with the critical value determined based on the FOD status packet received in the negotiation step. By comparing values to determine the presence or absence of foreign substances, there is an advantage that the probability of failure in foreign substance detection can be significantly reduced.

[0316] FIG. 10 is an experimental result graph showing the degree to which the quality recognition value decreases compared to the reference quality factor value when foreign substances are arranged in the charging area according to an embodiment of the present invention.

[0317] The experimental results shown in FIG. 10 are the experimental results when a 10 - cent copper coin is arranged in the charging area.

[0318] Referring to reference numerals 1010 and 1030 in FIG. 10, after arranging a 10 - cent copper coin in the charging area, the absolute amount (diff1) by which the quality factor value decreases compared to the reference quality factor value indicates that it increases as the reference quality factor value increases. At this time, the relationship between the quality factor (NO_FO) value measured when no foreign substance is arranged, that is, the reference quality factor (RFQ) value and diff1 can be approximated by the mathematical formula of reference numeral 1011. Although the above - mentioned reference numeral 1011 is approximated by a quadratic equation, this is only one embodiment, and it should be noted that it can also be approximated by a linear equation, other higher - order equations, exponential equations, etc.

[0319] Referring to reference numerals 1020 and 1030 in FIG. 10, after arranging a 10 - cent copper coin in the charging area, the ratio (%diff1) by which the quality factor value decreases compared to the reference quality factor value indicates that it increases as the reference quality factor value increases. At this time, the relationship between the quality factor (NO_FO) value measured when no foreign substance is arranged, that is, the reference quality factor (RFQ) value and %dif f1 can be approximated by the mathematical formula of reference numeral 1021. As described above, reference numeral 1​​​​​​​​​​​​​ 021 was approximated by a quadratic equation, but this is only one example, and it should be noted that it can also be approximated by a linear equation, other higher order equations, exponential equations, etc. 。

[0320] Figure 11 is an experimental result graph showing the degree to which the quality recognition value decreases compared to the reference quality factor value when a foreign substance is placed in the charging area according to another embodiment of the present invention.

[0321] The experimental results shown in Figure 11 are the experimental results when a quarter is placed in the charging area. 。

[0322] Referring to reference numerals 1110 and 1130 in Figure 11, after placing a quarter in the charging area, the absolute amount (diff2) by which the quality factor value decreases compared to the reference quality factor value indicates that it increases as the reference quality factor value increases. At this time, the relationship between the quality factor (NO_FO) value measured when no foreign substance is placed, that is, the reference quality factor (RFQ) value and di ff2 can be approximated by the mathematical formula of reference numeral 1111. The aforementioned reference numeral 1111 was approximated by a quadratic equation, but this is only one example, and it should be noted that it can also be approximated by a linear equation, other higher order equations, exponential equations, etc. 1111 was approximated by a quadratic equation, but this is only one example, and it should be noted that it can also be approximated by a linear equation, other higher order equations, exponential equations, etc. 。

[0323] Referring to reference numerals 1120 and 1130 in Figure 11, after placing a quarter in the charging area, the ratio (%diff2) by which the quality factor value decreases compared to the reference quality factor value indicates that it increases as the reference quality factor value increases. At this time, the relationship between the quality factor (NO_FO) value measured when no foreign substance is placed, that is, the reference quality factor (RFQ) value and diff 2 ​​The relationship of 2 can be approximated by the formula of reference numeral 1121. As described above, reference numeral 11 21 was approximated by a quadratic equation, but this is only one example, and it should be noted that it can also be approximated by a linear equation, other higher-order equations, exponential equations, etc.

[0324] As described above, in the wireless power transmission device according to the present invention, if an object is detected in the selection stage, the quality factor value of the resonance circuit is measured (or calculated) before entering the ping stage, and based on the critical value determined according to the received FOD state packet in the negotiation stage and the measured quality factor value, by comparing to determine the presence or absence of foreign substances, there is an advantage that the probability of failure in detecting foreign substances can be significantly reduced.

[0325] FIG. 12 shows the measurement results of the quality factor value and inductance value according to the presence or absence of foreign substances for different receiver types with respect to the resonance circuit.

[0326] Reference numeral 1210 indicates the inductance value (Ls), resistance value (Rs), and quality factor value (Q) of the resonance circuit measured in state 1211 where nothing is arranged in the charging area, state 1212 where only foreign substances are arranged, and state 1213 where only the receiver is arranged.

[0327] Reference numeral 1220 indicates the inductance value (Ls), resistance value (Rs), and quality factor value ( Q) of the resonance circuit measured for different receiver types in a state where both foreign substances and the receiver are arranged in the charging area.

[0328] Referring to reference numeral 1211, the inductance value of the resonance circuit measured in the state (Empty Pad) where nothing is arranged on the charging bed of the wireless power transmission device is 25.20 μ It is H, and the quality factor value is 133.8.

[0329] Referring to the drawing reference numeral 1210, when foreign substances such as foreign matter including FO#4 and a dime are arranged in a state where nothing is arranged in the charging area, the inductance value decreases. On the other hand, when a receiver capable of wireless power reception, such as a smartphone equipped with a wireless charging module, is arranged in a state where nothing is arranged in the charging area, the inductance value increases. Also, referring to the drawing reference numeral 1210, when foreign substances

[0330] or a receiver is arranged in a state where nothing is arranged in the charging area, the quality factor values all decrease. In particular, in the case of Receiver 2 and Receiver 4, it shows that the quality factor value drops more than that of FO#4.

[0331] Referring to the drawing reference numeral 1220, when the standard foreign matter FO#4 and a dime are further arranged respectively in a state where a receiver is arranged in the charging area, as shown by the drawing reference numerals 1221 and 1 222, both the inductance value and the quality factor value become low. However, the ratio at which the inductance value and the quality factor value become low differs depending on the type of receiver. As an example, referring to the drawing reference numerals 1213, 1221, and 1222, in the case of Receiver 1, when a foreign substance is further arranged, it shows that the change in the quality factor value is larger than the change in the inductance value. Therefore, in the case of Receiver 1, in order to determine the presence or absence of a foreign substance, it may be advantageous to sense the change in the quality factor value rather than the inductance value. On the other hand, in the case of Receiver 4, when a foreign substance is further arranged, it shows that the change in the inductance value is larger than the change in the quality factor value. Therefore, in the case of Receiver 4, in order to determine the presence or absence of a foreign substance, it may be advantageous to sense the change in the inductance value rather than the quality factor value. In the case of the receiver 4, in order to determine the presence or absence of a foreign substance, it may be advantageous to sense a change in the inductance value from the quality factor value. It may be possible to sense a change in the inductance value of the inductor from the quality factor value in order to determine the presence or absence of a foreign substance.

[0332] It is possible to identify which type of receiver the receiver disposed in the charging area is at the identification and configuration stage. Therefore, after sensing an object in the selection stage and before entering the ping stage, the wireless power transmitter cannot identify the type of the receiver.

[0333] Therefore, according to an embodiment of the present invention, when an object is sensed in the selection stage, the wireless power transmitter can measure and store all the inductance value and quality factor value of the resonance circuit before entering the ping stage. It can be stored.

[0334] Thereafter, the wireless power transmitter can determine an inductance threshold value and a quality factor threshold value for foreign substance sensing based on the FOD status packet received in the negotiation stage. Without The wireless power transmitter can determine an inductance threshold value and a quality factor threshold value for foreign substance sensing based on the FOD status packet received in the negotiation stage. The wireless power transmitter can compare the determined threshold values with the already stored inductance value and quality factor value to determine the presence or absence of a foreign substance.

[0335] As an example, when the wireless power transmitter compares the stored inductance value with the determined induct ance threshold value and determines that a foreign substance exists, or when the stored quality factor value is determined When it is determined that a foreign substance exists by comparing with the determined quality factor threshold value, finally, it can be determined that a foreign substance is disposed in the charging area. It can be determined that a foreign substance is disposed in the charging area.

[0336] In the above-described embodiment, it has been described that the wireless power transmitter determines a threshold value for foreign substance sensing based on the FOD status packet, but this is only one embodiment, and the critical range is only one example, and the critical range It is also possible to determine the enclosure. In this case, when the stored inductance value or (and) the quality factor value is out of the determined critical range, it can be determined that a foreign substance is present as well.

[0337] The foreign substance detection method in the wireless power transmitter according to another embodiment of the present invention may further include the step of receiving a received power intensity packet for power correction from the wireless power receiver. At this time, the received power intensity packet may include the received power of the wireless power receiver corresponding to the light load or the received power of the wireless power receiver corresponding to the load connection state.

[0338] FIG. 13a is a diagram for explaining the message structure of the FOD status packet according to still another embodiment of the present invention.

[0339] Referring to FIG. 13a, the FOD status packet message 1340 may have a length of 1 byte and may include an operating frequency (Operating Frequency for Maximum Quality Factor Value) 1340 field for the maximum quality factor value of 6-bit length and a mode 1342 field of 2-bit length. g Frequency for Maximum Quality Factor V alue) 1340 field and a mode (Mode) 1342 field of 2-bit length.

[0340] If there is an operating frequency in the upper band where the measured quality factor value is higher than the quality factor value measured at the operating frequency having the maximum quality factor value, the wireless power transmitter according to an embodiment of the present invention can determine that a foreign substance is present in the charging area. Here, the operating frequency in the upper band means any frequency greater than the operating frequency having the maximum quality factor value within the operating frequency band.

[0341] ​​​​​​​​ According to yet another embodiment of the present invention, a wireless power transmitter has a quality factor peak operating frequency in a frequency band higher than the operating frequency having the maximum quality factor value (i.e., the operating frequency at which the maximum quality factor value is measured among the quality factor values measured before the ping stage). If there is such a frequency, it can be determined that there is a foreign substance in the charging area. For example, the operating frequency 1341 for the maximum quality factor value may be the operating frequency for the maximum quality factor value corresponding to the type of wireless power transmitter confirmed at 230 of FIG. 2 identification and configuration stage. As an example, operating frequency information for different maximum quality factor values for wireless power transmitter types connectable to the wireless power receiver for this purpose can be maintained in a predetermined recording area. The operating frequency for the maximum quality factor value varies depending on the power level, design form, manufacturer, applied standard, etc. of the wireless power transmitter. Therefore, if it is confirmed at which operating frequency or within which operating frequency range the maximum quality factor value is present in relation to the corresponding wireless power receiver, the frequency range in which the quality factor value must be measured for the corresponding wireless power transmitter to search for the presence of foreign substances can be minimized. That is, the wireless power transmitter does not have to perform quality factor value measurement for a frequency band lower than the operating frequency for the maximum quality factor value.

[0342] As another example, the operating frequency 1341 for the maximum quality factor value may be for a specific coil type defined by the WPC standard, for example, the operating frequency for the maximum quality factor value corresponding to a wireless power transmitter equipped with a transmitting coil of the MP - A1 type coil type, but not limited to this. For the wireless power transmitter, if there is a quality factor peak operating frequency in a frequency band higher than the operating frequency having the maximum quality factor value (i.e., the operating frequency at which the maximum quality factor value is measured among the quality factor values measured before the ping stage), it can be determined that there is a foreign substance in the charging area when there is such a frequency. As an example, the operating frequency 1341 for the maximum quality factor value may be the operating frequency for the maximum quality factor value corresponding to the type of wireless power transmitter confirmed at 230 of FIG. 2 identification and configuration stage. For this wireless power receiver, operating frequency information for different maximum quality factor values for wireless power transmitter types connectable to it can be maintained in a predetermined recording area. The operating frequency for the maximum quality factor value depends on factors such as the power level, design form, manufacturer, and applied standard of the wireless power transmitter. Therefore, once it is confirmed at which operating frequency or within which operating frequency range the maximum quality factor value exists in relation to the relevant wireless power receiver, the frequency range in which the quality factor value needs to be measured by the relevant wireless power transmitter to search for the presence of foreign substances can be minimized.

[0343] That is, the wireless power transmitter does not need to perform quality factor value measurement for a frequency band lower than the operating frequency for the maximum quality factor value. For the wireless power transmitter, if there is a quality factor peak operating frequency in a frequency band higher than the operating frequency having the maximum quality factor value (i.e., the operating frequency at which the maximum quality factor value is measured among the quality factor values measured before the ping stage), it can be determined that there is a foreign substance in the charging area when there is such a frequency. As an example, the operating frequency 1341 for the maximum quality factor value may be the operating frequency for the maximum quality factor value corresponding to the type of wireless power transmitter confirmed at 230 of FIG. 2 identification and configuration stage. For this wireless power receiver, operating frequency information for different maximum quality factor values for wireless power transmitter types connectable to it can be maintained in a predetermined recording area. The operating frequency for the maximum quality factor value depends on factors such as the power level, design form, manufacturer, and applied standard of the wireless power transmitter.

[0344] Therefore, once it is confirmed at which operating frequency or within which operating frequency range the maximum quality factor value exists in relation to the relevant wireless power receiver, the frequency range in which the quality factor value needs to be measured by the relevant wireless power transmitter to search for the presence of foreign substances can be minimized. That is, the wireless power transmitter does not need to perform quality factor value measurement for a frequency band lower than the operating frequency for the maximum quality factor value. As another example, the operating frequency 1341 for the maximum quality factor value may be for a specific coil type defined by the WPC standard, for example, the operating frequency for the maximum quality factor value corresponding to a wireless power transmitter equipped with a transmitting coil of the MP - A1 type coil type, but not limited to this. It can also be a wave number. Based on the MP-A1 type, other types of wireless power transmitters Considering the design differences and product characteristics, the magnitude of the received maximum quality factor value can be adjusted (sca ling) and used to determine the presence or absence of foreign substances.

[0345] The wireless power transmitter according to an embodiment of the present invention measures and stores the quality factor value a1 for a specific upper limit frequency among the operating frequency bands at the ping stage 220 (or before the ping stage) of FIG. 2 It can be done. Alternatively, the maximum quality factor among the quality factors measured within a preset frequency range (within the operating frequency range) and the frequency at which the maximum quality factor is measured can be stored It can be done. Thereafter, the wireless power transmitter measures the quality factor value a2 at the operating frequency 1341 for the maximum quality factor value received via the FOD status packet 1340 in the negotiation stage 240. If a 1 is greater than a2, it can also be determined that a foreign substance exists in the charging area. Or The wireless power transmitter compares the operating frequency for the maximum quality factor value received via the FOD status packet 1340 in the negotiation stage 240 with the maximum quality factor and the frequency at which it is measured at the ping stage 220 (or before the ping stage) to determine the presence or absence of foreign substances It can be done

[0346]

[0347] If the frequency at which the maximum quality factor measured at the ping stage 220 is greater than the operating frequency of the received maximum quality Factor, it can be determined that a foreign substance exists. This principle will be described in detail below.

[0347] In this embodiment, the wireless power transmitter can also measure only the quality factor value for the upper limit frequency among the operating frequency Bands at the ping stage 220 (or before the ping stage). This is an example is only, and other embodiments can measure all the quality factor values for the lower and upper frequencies as well. Further, other embodiments can sweep from the lower frequency to the upper frequency to measure each quality factor value for each frequency.

[0348] Still other embodiments can sweep within a specific frequency range to measure each quality factor value for each frequency to be determined.

[0349] The wireless power transmitter is defined to measure the quality factor value for the lower frequency among the operating frequency bands at the ping stage 220. In this embodiment, although the wireless power transmitter can also measure only the quality factor value for the upper frequency among the operating frequency bands at the ping stage 220, this is only one embodiment, and other embodiments can also measure all the quality factor values for the lower and upper frequencies as well. This is only one embodiment, and other embodiments can also measure all the quality factor values for the lower and upper frequencies as well.

[0350] For the operating frequency 1341 field for the maximum quality factor value according to one embodiment, the frequency offset value from the lower frequency within the operating frequency, that is, the lowest frequency, can be recorded . Here, the offset unit can actually mean 10 KHz, but it is not limited to this, and it can be smaller or larger. As an example, if the operating frequency band of the corresponding wireless power transmitter is between a lower frequency of 100 KHz and an upper frequency of 300 KHz, the offset unit is 10 KHz, and the value recorded in the operating frequency 1341 field for the maximum quality factor value is the binary number 000011, then the actual frequency for the maximum quality factor value can be 130 K Hz (100 KHz + 3 * 10 KHz). Hz (100 KHz + 3 * 10 KHz). Hz (100 KHz + 3 * 10 KHz). Hz (100 KHz + 3 * 10 KHz). Hz (100 KHz + 3 * 10 KHz). Hz (100 KHz + 3 * 10 KHz).

[0351] In yet another embodiment, before the pinging phase, the wireless power transmitter can measure the quality factor value by sweeping the entire operating frequency band or a specific frequency band within the entire operating frequency band.

[0352] In yet another embodiment, instead of the field 1341 into which the operating frequency for the maximum quality factor value in FIG. 13a is inserted, an operating frequency value at which the quality factor value is already set by a value (or ratio) greater than the reference quality factor value can be inserted into the field 1341.

[0353] The wireless power transmitter can determine the presence or absence of foreign matter by comparing the quality factor value B1 measured at the reference operating frequency (for example, the operating frequency for measuring the quality factor value is 100 kHz) during the pinging phase 220 (or before the pinging phase) with the quality factor value B2 measured at an operating frequency greater than the received operating frequency.

[0354] At this time, if B2 is greater than B1, it can be determined that foreign matter is present.

[0355] FIG. 13b is a diagram for explaining the message structure of the FOD status packet according to yet another embodiment of the present invention.

[0356] Referring to FIG. 13b, the FOD status packet message 1350 can have a length of 2 bytes, and includes an operating frequency (Operating Frequency for Maximum Quality Factor V alue) 1351 field with a length of 6 bits, a mode 1352 field with a length of 2 bits and a reference quality factor value (Reference Quality Facto r) 1353 field with a length of 1 byte. ​​​​​​It can include an r Value) 1353.

[0357] The wireless power transmitter can also check whether the operating frequency 1351 for the maximum quality factor value is included in the FOD status packet received according to the mode 1352 value, but it is not limited to this. Regardless of the mode 1352 value, the operating frequency 1351 for the maximum quality factor value can always be included in the FOD status packet. Regardless of this, it is not limited, and the operating frequency 1351 for the maximum quality factor value can always be included in the FOD status packet regardless of the mode 1352 value. Regardless of this, it is not limited, and the operating frequency 1351 for the maximum quality factor value can always be included in the FOD status packet regardless of the mode 1352 value. Regardless of this, it is not limited, and the operating frequency 1351 for the maximum quality factor value can always be included in the FOD status packet regardless of the mode 1352 value.

[0358] If the wireless power transmitter receives the FOD status packet of FIG. 7a, it can compare the reference quality factor value with the quality factor value measured at the pin g stage 220 (or before the pinging stage) to determine the presence or absence of foreign substances (Method 1), or compare the operating frequency for the maximum quality factor value with the maximum operating frequency corresponding to the maximum quality factor value measured at the pinging stage 220 (or before the pinging stage) to determine the presence or absence of foreign substances (Method 2, the embodiment of FIG. 13a). If the wireless power transmitter receives the FOD status packet of FIG. 7a, it can compare the reference quality factor value with the quality factor value measured at the pin g stage 220 (or before the pinging stage) to determine the presence or absence of foreign substances (Method 1), or compare the operating frequency for the maximum quality factor value with the maximum operating frequency corresponding to the maximum quality factor value measured at the pinging stage 220 (or before the pinging stage) to determine the presence or absence of foreign substances (Method 2, the embodiment of FIG. 13a). If the wireless power transmitter receives the FOD status packet of FIG. 7a, it can compare the reference quality factor value with the quality factor value measured at the pin g stage 220 (or before the pinging stage) to determine the presence or absence of foreign substances (Method 1), or compare the operating frequency for the maximum quality factor value with the maximum operating frequency corresponding to the maximum quality factor value measured at the pinging stage 220 (or before the pinging stage) to determine the presence or absence of foreign substances (Method 2, the embodiment of FIG. 13a). If the wireless power transmitter receives the FOD status packet of FIG. 7a, it can compare the reference quality factor value with the quality factor value measured at the pin g stage 220 (or before the pinging stage) to determine the presence or absence of foreign substances (Method 1), or compare the operating frequency for the maximum quality factor value with the maximum operating frequency corresponding to the maximum quality factor value measured at the pinging stage 220 (or before the pinging stage) to determine the presence or absence of foreign substances (Method 2, the embodiment of FIG. 13a). If the wireless power transmitter receives the FOD status packet of FIG. 7a, it can compare the reference quality factor value with the quality factor value measured at the pin g stage 220 (or before the pinging stage) to determine the presence or absence of foreign substances (Method 1), or compare the operating frequency for the maximum quality factor value with the maximum operating frequency corresponding to the maximum quality factor value measured at the pinging stage 220 (or before the pinging stage) to determine the presence or absence of foreign substances (Method 2, the embodiment of FIG. 13a).

[0359] Or, the presence or absence of foreign substances can be determined by a composite method.

[0360] In one embodiment, the wireless power transmitter can determine the presence or absence of foreign substances by Method 1. At this time, two critical values (Critical value 1: Q_Threshold1 and Critical value 2: Q_Threshold2) can be determined based on the reference quality factor value received. Critical value 1 has a higher value than Critical value 2. In one embodiment, the wireless power transmitter can determine the presence or absence of foreign substances by Method 1. At this time, two critical values (Critical value 1: Q_Threshold1 and Critical value 2: Q_Threshold2) can be determined based on the reference quality factor value received. Critical value 1 has a higher value than Critical value 2. In one embodiment, the wireless power transmitter can determine the presence or absence of foreign substances by Method 1. At this time, two critical values (Critical value 1: Q_Threshold1 and Critical value 2: Q_Threshold2) can be determined based on the reference quality factor value received. Critical value 1 has a higher value than Critical value 2. In one embodiment, the wireless power transmitter can determine the presence or absence of foreign substances by Method 1. At this time, two critical values (Critical value 1: Q_Threshold1 and Critical value 2: Q_Threshold2) can be determined based on the reference quality factor value received. Critical value 1 has a higher value than Critical value 2.

[0361] If the quality factor value measured before the pinging stage 220 is smaller than Critical value 2, the wireless power transmitter can determine that foreign substances are present. If the quality factor value measured before the pinging stage 220 is smaller than Critical value 2, the wireless power transmitter can determine that foreign substances are present.

[0362] If the quality factor value measured before the ping stage 220 is less than the critical value 1 and is the same as or greater than the critical value 2, the wireless power transmitter can determine the presence or absence of a foreign substance by method 2.

[0363] FIG. 13c is a diagram for explaining the message structure of an FOD status packet according to still another embodiment of the present invention.

[0364] Referring to FIG. 13c, the FOD status packet message 1360 can have a length of 2 bytes, a 6-bit long wireless power transmitter type (Tx Type) 1361, a 2-bit long mode (Mode) 1362 field, and a 1-byte long operating frequency for the maximum quality factor value (Operating Frequency for Maximum Quality Factor Value) 1363 field.

[0365] The wireless power transmitter can confirm whether the received FOD status packet contains the wireless power transmitter type 1361 information and the operating frequency 1363 information for the maximum quality factor value according to the mode 1362 value, but is not limited thereto. Regardless of the mode 1362 value, the FOD status packet can always contain the wireless power transmitter type 1361 information and the operating frequency 1363 information for the maximum quality factor value.

[0366] As an example, the wireless power transmitter type 1361 can be a value (a predetermined classification number) indicating a predetermined transmitter design number (Tx Design Number) for uniquely identifying the registered wireless power transmitter during WPC (Qi) certification.

[0367] ​​​​​​​​​​​​​​As another example, the wireless power transmitter type 1361 may also be a predetermined classification number for classifying wireless power transmitters having common design features and performance characteristics.

[0368] A wireless power transmitter according to an embodiment of the present invention, if there exists an operating frequency in the upper band where a quality factor value higher than the quality factor value measured at the operating frequency having the maximum quality factor value is measured, it can be determined that there is a foreign object in the charging area. Here, the upper band operating frequency means any frequency greater than the operating frequency having the maximum quality factor value within the operating frequency band.

[0369] A wireless power transmitter according to still another embodiment of the present invention, if there exists a quality factor peak operating frequency in the upper band (the operating frequency at which the maximum quality factor value among the quality factor values measured before the ping stage is measured) higher than the operating frequency having the maximum quality factor value, it can be determined that there is a foreign object in the charging area.

[0370] Hereinafter, for convenience of explanation, the reference quality factor value measured when there is no foreign object is denoted as R QF_NO_FO, and the quality factor value measured when a specific foreign object exists is denoted as QF_FO. As an example, the specific foreign object may be a 22 mm diameter and 1 mm thick aluminum disk, Foreign Object #4 (hereinafter, for convenience of explanation, abbreviated as FO4), but is not limited thereto, and any one of common and commonly used copper coins can also be used.

[0371] Before the wireless power transmitter performs the ping stage, that is, at the selection stage, the current quality factor value is measured. ​​​​​​The wireless power transmitter determines the reference quality factor value ( Reference Quality Factor Value) and transmitter-specific design Production and measurement error values to account for technical differences urement tolerance) and the reference quality factor Accuracy f Reference Quality Factor) to determine whether or not there are any foreign substances. A critical value of the quality factor for determining nullity is determined.

[0372] The reference quality factor value is calculated using a test power transmitter (TPT). tter), for example, five charging areas (middle) of the MP1 (MP-A1) type transmitter The minimum quality factor value measured at the four positions (the center position and four positions shifted 5 mm left, right, up, and down) This means that the design differences between the MP1 test power transmitter and commercial wireless power transmitters, such as The quality factor actually measured in the charging area depends on the difference in the inductance value of the transmitting coil, for example. The value varies depending on the transmitter, and the error that must be corrected is called production and measurement error.

[0373] For example, the reference quality factor drop value 1321 may be a reference quality factor corresponding to the wireless power receiver. The value is determined by subtracting the quality factor value measured in the presence of a specific foreign substance from the product value. can be done.

[0374] As another example, the reference quality factor drop value 1321 is the value measured when no foreign material is present. It is the ratio of the drop in the quality factor value measured in the presence of foreign matter to the quasi-quality factor value. In this case, the reference quality factor drop value 1321 is calculated as a percentage (%) or It can be an integer value calculated by dividing the rate by a specific unit value (STEP_VALUE), but is not limited thereto. As an example, the reference quality factor drop value 1321 can be calculated by the following Equation 1 as follows.

[0375] Equation 1:

[0376] [(RQF_NO_FO - QF_FO) / RQF_NO_FO]*100 or

[0377] [((RQF_NO_FO - QF_FO) / RQF_NO_FO)*100] / STE P_VALUE

[0378] (Here, *100 is for expressing in %, and the actual value may be a value without *100 reflected)

[0379] The reference quality factor drop value varies depending on the manufacturer or (and) product type of the wireless power receiver. .

[0380] Therefore, the wireless power transmitter according to an embodiment of the present invention can obtain from the wireless power receiver that senses the reference quality factor drop value, and can adaptively determine a quality factor threshold for determining the presence or absence of a foreign substance in consideration of the reference quality factor drop value.

[0381] Thereby, the present invention can minimize the problem that although a foreign substance is actually located in the charging area, the foreign substance is not normally detected, resulting in heat generation or a sharp drop in power transmission efficiency.

[0382] FIG. 13d is a diagram for explaining the message structure of an FOD state packet according to an embodiment of the present invention.

[0383] ​Referring to FIG. 13d, the FOD state packet message 1300 can have a length of 2 bytes and can include a 6-bit length Reserved 1301, a 2-bit length Mode 1302 field, and a 1-byte length Reference Quality Factor Value 1303.

[0384] All bits constituting the Reserved 1301 field can be set to 0.

[0385] Referring to the reference numeral 1304, if the Mode 1302 field is binary '00', it means that the reference quality factor (RQF_NO_FO, first reference quality factor) value in the state without FO is recorded in the reference quality factor value 1303 field, and if the Mode 1302 field is binary '01', it can mean that the reference quality factor (RQF_FO, second reference quality factor) value in the state with FO is recorded in the reference quality factor value 1303 field.

[0386] FIG. 13e is a diagram for explaining the message structure of the FO state packet according to another embodiment of the present invention.

[0387] Referring to FIG. 13e, the FO state packet message 1310 can have a length of 3 bytes and can include a 6-bit length Reserved 1311, a 2-bit length Mode 1312 field, a reference quality factor value (Reference Quali ty Factor Value) 1313, and a reference quality factor value in the presence of foreign substances (Ref erence Quality Factor Value With Foreign ​​​​It can include an object) 1314.

[0388] All bits constituting the reservation 1301 field can be set to 0.

[0389] The operation mode of the power receiving machine to which the corresponding reference quality factor value 1313 is applied via the mode 1312 field can be identified. Referring to the reference numeral 1315, if the mode 13 12 value is the binary number '00', it means the reference quality factor value measured with the power of the wireless power receiver in the OFF state.

[0390] The wireless power receiver has different reference quality factor values measured when there is no foreign substance by manufacturer or (and) product type and the reference quality factor value measured when there is a foreign substance.

[0391] The wireless power transmitter according to an embodiment of the present invention can adaptively determine a quality factor threshold for determining the presence or absence of a foreign substance in consideration of the reference quality factor value measured when there is no foreign substance and the reference quality factor value measured when there is a foreign substance. This is because the amount of change in the quality factor value due to the presence of a foreign substance is different for each receiver. Thereby, the present invention can minimize the problem that although a foreign substance is actually located in the charging area, the foreign substance is not normally detected and heat is generated or the power transmission efficiency drops significantly.

[0392] FIG. 13f is a diagram for explaining the message structure of the FO state packet according to still another embodiment of the present invention.

[0393] Referring to FIG. 13f, the FO state packet message 1120 has a length of 2 bytes. ​​​​​​​​and can have a 6-bit long reference quality factor drop value (Drop Value of Re ference Quality Factor) 1321 field, a 2-bit long mode 1322 field, and a reference quality factor value (Reference Qua lity Factor Value) 1323 field.

[0394] Here, the reference quality factor drop value 1321 is based on the reference quality factor value 1223 measured when there is no foreign matter and the quality factor value (Quality Fa ctor Value With Foreign Object) measured when a specific foreign matter exists, and can be a value determined thereby.

[0395] The mode 1322 field can be used to indicate that the reference quality factor drop value 1321 is recorded in the reserved 1301 field of FIG. 13d. As an example, referring to the plane code 1324 in FIG. ure, if the value of the mode 1322 field is the binary number '01', it can mean that the reference quality factor drop value 1321 is recorded in the reserved field, but this is only one embodiment, and other values of the mode 1322 field, such as the binary number '10' or the binary number '11', can also be used to indicate that the reference quality factor drop value 1321 is recorded in the reserved field. However, when other values other than the binary number '00' are set for the mode 1322 field value , the reference quality factor value 1323 can automatically include the value measured when the power of the power receiver is in the OFF state.

[0396]

[0397] For convenience of explanation, the format of the foreign substance state packet is described by specific examples according to the mode. Although it has been described separately according to the mode, the foreign substance state packet can be in the form of the embodiments shown in FIGS. 13d to 13g regardless of the mode.

[0398] FIG. 13g is a diagram for explaining the message structure of the FO state packet according to still another embodiment of the present invention.

[0399] Referring to FIG. 13g, the FO state packet message 1330 can have a length of 2 bytes, and includes a 6-bit reference quality factor accuracy (Accuracy of Reference Quality Factor) 1331 field, a 2-bit mode 1332 field, and a reference quality factor value (Reference Quality Factor Value) 1333 field.

[0400] Here, the reference quality factor accuracy 1331 can be an allowable error value with respect to the reference quality factor value 1333 measured when no foreign substance is present. As an example, the reference quality factor value to which the allowable error value is applied can be set at a ratio of increase or decrease compared to the reference quality factor value 1333 received from the radio power receiving device, but is not limited thereto.

[0401] The reference quality factor accuracy 1331 can have different values depending on the manufacturer (or) and product type of the corresponding radio power receiver. As an example, the radio power receivers of Company A and Company B are linked to the same radio power transmitter, and the accuracies of the measured reference quality factor values are different from each other. Therefore, the radio power transmitter obtains information about the reference quality factor accuracy for each radio power receiver. ​​​​​​​​​​​​It is necessary to obtain a quality factor threshold that can determine the presence or absence of foreign substances in consideration of the reference quality factor accuracy. Also, for the convenience of explanation below, the wireless power transmitter simply names the quality factor threshold for determining the presence or absence of foreign substances as FO_QF_THRESH OLD.

[0402] As an example, for the test results of the same wireless power transmitter, the reference quality factor value measured for the wireless power receiver of Company A can be 100, and the reference quality factor value measured for the wireless power receiver of Company B can be 70. In this case, the reference quality factor accuracy corresponding to the wireless power receiver of Company B, for example, within + / -7%, can be set higher than the reference quality factor accuracy corresponding to the wireless power receiver of Company A, for example, within + / -10%. That is, the sensitivity to errors can be set higher for the wireless power receiver of Company B than that of Company A.

[0403] Thus, the quality factor accuracy can vary depending on the configuration of the finished product in which the receiver is installed. For example, due to the PCB, camera module, antenna, and other components mounted on the finished product, the quality factor can be measured lower than that of other finished products even in the absence of foreign substances. As a result, in the case of the finished product located in the charging area together with foreign substances, the difference in the quality factor value may be smaller compared to other finished products, and therefore higher measurement accuracy is required

[0404] The mode 1332 field can be used to indicate that the reference quality factor accuracy 1331 is recorded in the reservation 1301 field of FIG. 13d. As an example, referring to the surface code 1334 in the figure, if the value of the mode 1332 field is the binary number '01' ​​​​​​​​​ It can mean that the reference quality factor accuracy 1331 is recorded in the reservation field, but this is only one embodiment, and other values of the mode 1332 field, such as the binary number ‘10’ or the binary number ‘11’, can also be used to indicate that the reference quality factor accuracy 1331 is recorded in the reservation field. However, when other values other than the binary number ‘00’ are set for the mode 1332 field value, the reference quality factor value 1333 can automatically include the fact that it is the value measured when the power of the power receiver is in the OFF state.

[0405] Figure 14 is a flowchart for explaining the FOD detection method according to another embodiment of the present invention.

[0406] Referring to Figure 14, in the negotiation stage, the wireless power receiver 1410 can transmit an FOD status packet including the second reference quality factor value (Second Reference Quality Factor Value, RQF _FO) to the wireless power transmitter 1420 (S1401). At this time, the mode value of the FOD status packet can be set to the binary number “0

[0407] 1”. The second reference quality factor value can be determined as the minimum value among the quality factor values measured at a plurality of points on the charging area of the specified specific wireless power transmitter and maintained in the wireless power receiver. As an example, the second reference quality factor value (RQF_FO) is the state where FO exists around the wireless power receiver placed in the charging area, and the primary coil and the receiving coil

[0408]

[0409] ​​​​​​​​​​ The first quality factor measured at the central position where the (Secondary Coil) is well aligned, and the minimum value among the second quality factor values measured while moving at a certain distance offset (for example, it can be + / −5 mm in the x-axis and y-axis directions respectively, but not limited to this) without rotating the wireless power receiver with FO present around the

[0410] wireless power receiver can be determined. Here, the second quality factor value can include quality factor values measured at at least four different positions. The wireless power transmitter 1420 can determine a threshold value for FO detection based on the received second

[0411] reference quality factor value and a configuration factor (Design factor) pre-stored corresponding to the wireless power transmitter 1420 (S1403). Hereinafter, for convenience of explanation, the second reference quality factor value corrected based on the configuration factor will be named as the compensated quality factor threshold (Q_threshold_correct). Since the second reference quality factor value is determined based on the quality factor value measured on a specified

[0412] As an example, the constituent factors are the power class corresponding to the applicable commercial wireless power transmitter (Power Class), the characteristics and arrangement structure of the transmission coil, the power control algorithm installed in the transmitter m, the power transfer loss (Power Transfer Loss), and a correction constant value determined based on at least one parameter of the shape and structure of the applicable wireless power transmitter and obtained, but not limited thereto, as long as it is a value that can correct the measurement error of the quality factor value for the test wireless power transmitter. The wireless power transmitter 1420 can measure the current quality factor value (Q_current) and compare whether the current quality factor value (Q_current) is greater than or equal to the corrected quality factor threshold value (Q_threshod_corr

[0413] ect) (S1403~S1404). For reference, the current quality factor value can also be determined before the digital ping stage, can also be measured before the negotiation (re-negotiation) stage, and can also be measured periodically. .

[0414]

[0415] If the comparison result shows that the current quality factor value (Q_current) is the same as or greater than the corrected quality factor threshold value (Q_thr eshod_correct), the wireless power transmitter 1420 determines that no FO is detected and can transmit an ACK response to the wireless power receiver 1410 (S1405). At this time, the state of the wireless power transmitter 1420 can transition from the negotiation stage to the power transmission stage. stage.

[0416] Based on the comparison result in the above-mentioned step 1404, if the current quality factor value (Q_current) is the corrected quality​​ If it is smaller than the factor threshold (Q_threshod_correct), the wireless power transmitter 1420 determines that FO has been detected and transmits a NAK response to the wireless power receiver 1410 (S1406). At this time, the state of the wireless power transmitter 1420 can transition from the negotiation stage to the selection stage.

[0417] FIG. 15 is a flowchart for explaining an FOD detection method according to still another embodiment of the present invention. - rate.

[0418] Referring to FIG. 15, in the negotiation stage, the wireless power receiver 1510 transmits first and second FOD status packets including a reference quality factor value (Ref erence Quality Factor Value, Q_reference) to the wireless power transmitter 1520 (S1501 to S1502). Here, the first FOD status packet can include a first reference quality factor value (RQF_NO_FO) when the mode is binary '00'.

[0419] Here, the first FOD status packet can include a first reference quality factor value (RQF_NO_FO) when the mode is binary '00'. The second FOD status packet can include a second reference quality factor value (RQF_FO) when the mode is 1, that is, a reference quality factor value determined based on the quality factor value measured in a state where FO exists in the charging area. exist. Here, the first reference quality factor value (RQF_NO_FO) is larger than the second reference quality factor value (RQF_ FO).

[0420] Here, the first reference quality factor value (RQF_NO_FO) is larger than the second reference quality factor value (RQF_ FO).

[0421] The first and second reference quality factor values can be determined based on the quality factor values measured in a state where FO is not around the receiver and a state where FO exists around the receiver, respectively. An example can be As for the first and second reference quality factor values, the value having the minimum value among the quality factor values measured at a plurality of points on the charging area of the specific test radio power transmitter can be determined.

[0422] The radio power transmitter 1520 can determine a quality factor threshold ratio (Q_threshold_rate) for FO detection based on the received first and second reference quality factor values (S1503).

[0423] Here, the quality factor threshold ratio (Q_threshold_rate) can be calculated by dividing the difference value between the first reference quality factor value (RQF_NO_FO) and the second reference quality factor value (RQF_FO) by the first reference quality factor value (RQF_NO_FO). As an example, when the first reference quality factor value (RQF_NO_FO) is 80 and the second reference quality factor value (RQF_FO) is 50, the quality factor threshold ratio (Q_threshold_rate) can be calculated as (80 - 50) / 80 = 0.6375.

[0424] The radio power transmitter 1520 measures the current quality factor value (Q_current) and can calculate a quality factor decrease ratio (Q_decrease_rate) based on the measured current quality factor value and the first reference quality factor value (RQF_NO_FO) (S1404).

[0425] For reference, the current quality factor value can also be determined before the digital ping stage, can also be measured immediately before the negotiation (re - negotiation) stage, and can also be measured periodically.

[0426] The wireless power transmitter 1520 can compare whether the quality factor reduction ratio (Q_decrease_rate) is smaller than the quality factor critical ratio (Q_threshold_rate) (S1505). If the comparison result is smaller, the wireless power transmitter 1520 determines that FO is not detected and can transmit an ACK response to the wireless power receiver 1510 (S1506). At this time, the state of the wireless power transmitter 1520 can transition from the negotiation stage to the power transmission stage.

[0427] If the comparison result in the above-mentioned step 1505 is that the quality factor reduction ratio (Q_decrease_rate) is the same as or greater than the quality factor critical ratio (Q_threshold_rate), the wireless power transmitter 1520 determines that FO is detected and can transmit a NAK response to the wireless power receiver 1510 (S1507). At this time, the state of the wireless power transmitter 1520 can transition from the negotiation stage to the selection stage.

[0428] In the embodiment of FIG. 15, the quality factor reduction ratio (Q_decrease_rate) and the quality factor critical ratio (Q_threshold_rate) are compared to perform FO detection. However, this is only one embodiment, and the wireless power transmitter according to other embodiments of the present invention can calculate a corrected quality factor critical ratio (Q_threshold_rate_correct) based on the constituent factors corresponding to the relevant wireless power transmitter, and compare the quality factor reduction ratio (Q_decrease_rate) with the corrected quality factor critical ratio (Q_threshold_rate_correct) to determine whether FO exists in the charging area.

[0429]

[0430] ​​​​​​​​​​​​​​ In yet another embodiment, the quality factor threshold can be determined as follows.

[0431] Based on the received reference quality factor value (Reference Quality Factor V alue), the quality factor measurement error range (ex ± 10% (0.61 * reference quality factor value), or Accuracy of Quality Factor Value (Figure 19g)), and transmitter characteristics (such as transmitter type (design), manufacturer, product, or measurement error), it can be determined.

[0432] Figure 16 shows a quality factor table according to an embodiment of the present invention.

[0433] The quality factor table 1600 shown in Figure 16 can be maintained in the memory of the wireless power transmitter. The wireless power transmitter can update the quality factor table 1 600 based on the received FO state packet. As an example, the quality factor table 1600 can include at least one of a receiver identifier 1601 field, a most recently measured quality factor value (Latest Measur ed Quality Factor Value) 1602 field, a first reference quality factor value (RQF_NO_FO) 1603 field, a second reference quality factor value (RQF_FO ) 1604 field, and a corrected quality factor threshold (Q_threshold_correc t) 1605 field.

[0434] Here, the receiver identifier 1601 is a manufacturer code (ma nufacturer code), a basic device identifier (Basic Device Identifier), and an extended device identifier (Extended Device I​ configured by combining any one or at least one of them For example, the receiver identifier can be formed by concatenating the manufacturer code and the basic device identifier As another example, the receiver identifier can be formed by concatenating the manufacturer code, the basic device identifier, and the extended device identifier as well

[0435] In the most recently measured quality factor value 1602 field, the quality factor value most recently measured corresponding to the relevant receiver identifier 1601 can be recorded At this time, when the charging for the wireless power receiver corresponding to the relevant receiver identifier 1601 is normally completed or a steady state transition to the power transmission state is made during the negotiation stage, the wireless power transmitter can record the quality factor value measured at the relevant negotiation stage in the quality factor table 1600

[0436] In addition, if the wireless power transmitter receives an FOD status packet during the negotiation stage, it can also record the second reference quality factor value (RQF_FO) or (and) the first reference quality factor value (RQF_NO_FO) included in the FOD status packet in the quality factor table 1600

[0437] In addition, the wireless power transmitter can also record the compensated quality factor threshold value (Q_threshold_correct) calculated for FO detection in the first negotiation stage with the relevant wireless power receiver in the quality factor table 1600

[0438] If a wireless power receiver corresponding to the receiver identifier recorded in the quality factor table 1600 is detected later, the wireless power transmitter can detect FO by referring to the quality factor table 1600 ​​​​​​​​​

[0439] The quality factor table 1600 according to another embodiment of the present invention is based on the criteria described in FIG. 13f It may further include at least one of the quality factor drop value 1321 and the reference quality factor accuracy 1331 described in FIG. 13d.

[0440] FIG. 17 is a block diagram for explaining the configuration of an FO detection device according to an embodiment of the present invention. .

[0441] The FO detection device 1700 according to an embodiment of the present invention can be attached to or mounted on a wireless power transmitter.

[0442] Referring to FIG. 17, the FO detection device 1700 includes a communication unit 1710, a determination unit 1720, a measurement unit 1730, a detection unit 1740, a control unit 1750, and a power transmission unit 1760.

[0443] The communication unit 1710 can receive an FOD status packet including a reference quality factor value from a wireless power receiver connected in the negotiation stage. Here, the reference quality factor value can include at least one of the reference quality factor value (RQF_NO_FO, first reference quality factor value) when FO is not present in the charging area and the reference quality factor value (RQF_FO, second reference quality factor value) when FO is present in the charging area, and can be received via one FOD status packet or a plurality of FOD status packets in the negotiation stage. ) and can be received via one FOD status packet or a plurality of FOD status packets.

[0444] The determination unit 1720 can determine a threshold value to be used at the time of FO detection based on the received reference quality factor value. As an example, the threshold value used at the time of FO detection is the second reference quality factor value (R ​​​​​​​It can be determined as QF_FO), but this is only one embodiment, and other embodiments of the present invention The threshold value used at the time of FO detection according to other embodiments of the present invention is based on the constituent factors corresponding to the corresponding radio power transmitter It can also be determined as the second reference quality factor value corrected accordingly.

[0445] The threshold value used at the time of FO detection according to still other embodiments of the present invention is the quality factor threshold ratio (Quality Factor Thr eshold Rate, Q_threshold_rate) calculated based on the first to second reference quality factor values, and it can also be determined. be.

[0446] In the first embodiment, the quality factor threshold ratio (Q_threshold_rate) is the difference value between the first reference quality factor value (RQF_NO_FO) and the second reference quality factor value (RQF_FO) divided by the first reference quality factor value (RQF_NO_FO). As an example, when the first reference quality factor value (RQF_NO_FO) is 80 and the second reference quality factor value (RQF_FO ) is 50, the quality factor threshold ratio (Q_threshold_rate) can be calculated as (80 - 5 0) / 80 = 0.6375.

[0447] In the second embodiment, the quality factor threshold ratio (Q_threshold_rate) can also be determined as the value obtained by dividing the second reference quality factor value (RQF_FO) by the first reference quality factor value (RQF_NO_FO). When the first reference quality factor value (RQF_NO_FO) is 80 and the second reference quality factor value (RQF_FO) is 50, the quality factor threshold ratio (Q_threshold_ rate) can be calculated as 50 / 80 = 0.6625. be.

[0448] The threshold value used during FO detection according to still another embodiment of the present invention is the first to second reference qualities The factor value is the first corrected reference quality factor calculated by applying configuration factors determined in advance according to the corresponding radio power transmitter, and the corrected quality factor critical ratio (Q_threshold_rate_correct) can also be determined.

[0449] The measurement unit 1730 can measure or calculate a value related to the current quality factor that is compared with the above-described threshold value during FO detection. For example, the measurement unit 1730 can measure

[0450] the current quality factor value (Q_current) during the negotiation stage. can be determined.

[0451] In addition, the measurement unit 1730 can calculate a quality factor decrease ratio (Q_decreas e_rate) based on the measured current quality factor value (Q_current) and the first reference quality factor value (RQF_NO_FO). Here, the quality factor decrease ratio (Q_decrea se_rate) can be calculated by [RQF_NO_FO - Q_current] / [RQF_NO_F O]. can be calculated by

[0452] In addition, the measurement unit 1730 can calculate a ratio (Q_curren t_rate) of the current quality factor based on the measured current quality factor value (Q_current) and the first reference quality factor value (RQF_NO_FO). Here, the ratio (Q_curre nt_rate) of the current quality factor can be calculated by [Q_current] / [RQF_NO_FO] can be calculated by can be calculated.

[0453] The detection unit 1740 can detect whether the FO exists in the charging area by comparing the threshold value determined by the determination unit 1720 with the value measured or calculated by the measurement unit 1730.

[0454] As an example, as shown in FIG. 20 described above, when the current quality factor value (Q _current) is smaller than the second reference quality factor value (RQF_FO), it can be determined that the FO exists in the charging area.

[0455] As another example, as shown in FIG. 14 described above, when the current quality factor value ( Q_current) is smaller than the compensated quality factor threshold value (Q_threshold_correct ), it can also be determined that the FO exists in the charging area.

[0456] As yet another example, as shown in FIG. 15 described above, the detection unit 1740 can determine whether the FO exists in the charging area by comparing the quality factor reduction ratio (Q_decrease_rate) with the quality factor critical ratio (Q_threshol d_rate).

[0457] As yet another example, the detection unit 1740 can determine whether the FO exists in the charging area by comparing the quality factor reduction ratio (Q_decrease_ rate) with the compensated quality factor critical ratio calculated based on the configuration factor corresponding to the corresponding wireless power transmitter.

[0458] As yet another example, the detection unit 1740 can determine the quality factor threshold value as follows.

[0459] The received reference quality factor value (Reference Quality Factor V ​​​​​​The quality factor measurement error range (ex±10% (0.61*referenceQ - FactorValue), or the accuracy of the quality factor value (Accuracy of Qual ity Factor Value (Fig. 11d)) and the transmitter characteristics (transmitter type (desig n), manufacturer, product, or measurement error, etc.) can be determined in consideration of.

[0460] The control unit 1750 can control the overall operation and input / output of the FO detection device 1700. As an example, when the FO is not detected by the detection unit 1740, the control unit 1750 can transition the state of the corresponding wireless power transmitter from the negotiation stage to the power transmission stage, and control the power transmission unit 17 60 to send the power required for load charging. As another example, when the FO is detected by the detection unit 1740, the control unit 1750 can transition the state of the corresponding wireless power transmitter from the negotiation stage to the selection stage, and control to cut off the power transmission of the power transmission unit 1760.

[0461] The FO detection device 1700 according to another embodiment of the present invention may further include a memory (not shown) for maintaining the quality factor table 1600 shown in FIG. 16.

[0462] The FO detection device 1700 according to still another embodiment of the present invention may further include a correction unit (not shown) for calculating the power loss between itself (wireless power transmitter) and the corresponding wireless power receiver before transitioning to the power transmission stage when the FO is not detected by the detection unit ........

[0463] FIG. 18 is a flowchart for explaining an FOD detection method according to an embodiment of the present invention.

[0464] Referring to FIG. 18, during the negotiation phase, the wireless power receiver 1810 can transmit an FOD status packet including a reference quality factor value (Re ference Quality Factor Value) and a reference quality factor drop value (Drop Value of Reference Quality Factor) to the wireless power transmitter 1820 (S1 801). At this time, the mode value of the FOD status packet can be set to the binary number "01", but is not limited thereto.

[0465] Here, the reference quality factor value is determined to be the minimum value among the quality factor values measured at a plurality of points in the charging area of a specific wireless power transmitter specified for performance testing and can be maintained in the wireless power receiver.

[0466] The wireless power transmitter 1820 can determine a quality factor threshold value (Quality Factor Threshold Value, Q _threshold) using the received reference quality factor value and reference quality factor drop value (S1803).

[0467] As an example, the wireless power transmitter 1820 can determine the value obtained by subtracting the reference quality factor drop value from the reference quality factor value as the quality factor threshold value, but is not limited thereto. Other examples are that the quality factor threshold value can also be determined using a predetermined quality factor threshold value generation function in which the reference quality factor value and the reference quality factor drop value are input variables.

[0468] The wireless power transmitter 1820 measures the current quality factor value (Q_current) and determines whether the current quality factor value (Q_current) is the same as the quality factor threshold value (Q_threshod) or not.​​​​​ it can be compared whether it is larger than that (S1803~S1804).

[0469] For reference, the current quality factor value can also be measured before the Digital Ping stage and can also be measured immediately before the negotiation (re-negotiation) stage, and can also be measured periodically after the Digital Ping stage.

[0470] As a comparison result, if the current quality factor value (Q_current) is the same as or larger than the quality factor threshold value (Q_thres hod), the wireless power transmitter 1820 determines that FO has not been detected and can transmit an ACK response to the wireless power receiver 1810 (S1805 ). At this time, the state of the wireless power transmitter 1820 can transition from the negotiation stage to the power transmission stage.

[0471] Based on the comparison result in the above-mentioned 1804 stage, if the current quality factor value (Q_current) is smaller than the quality factor threshold value (Q_threshod), the wireless power transmitter 1820 determines that FO has been detected and can transmit a NAK response to the wireless power receiver 1810 (S18 06). At this time, the state of the wireless power transmitter 1820 can transition from the negotiation stage to the selection stage.

[0472] FIG. 19 is a flowchart for explaining an FOD detection method according to another embodiment of the present invention.

[0473] Referring to FIG. 19, in the negotiation stage, the wireless power receiver 1910 has a reference quality factor accuracy ( Accuracy of Reference Quality Factor) and a reference quality factor value (Reference Quality Factor Value) included The rare FOD state packet can be transmitted to the wireless power transmitter 1920 (S190 1). At this time, the mode value of the FOD state packet can be set to the binary number "01", but it is not limited to this.

[0474] The wireless power transmitter 1920 uses the received reference quality factor accuracy and reference quality factor value to determine the quality factor threshold value (Quality Factor Threshold Value, Q _threshold) (S1903).

[0475] The wireless power transmitter 1920 according to an embodiment of the present invention also uses the pre-stored production and measurement errors (production and measurement tolerance) to determine the quality factor threshold value.

[0476] As an example, the wireless power transmitter 1920 can determine the quality factor threshold value as the value obtained by subtracting the reference quality factor accuracy and production and measurement errors from the reference quality factor value, but it is not limited to this. Another example is that the quality factor threshold value can also be determined using a predetermined quality factor threshold value generation function with the reference quality factor accuracy and reference quality factor value as input variables.

[0477] The wireless power transmitter 1920 measures the current quality factor value (Q_current) and compares whether the current quality factor value (Q_current) is the same as or greater than the quality factor threshold value (Q_threshod) (S1903~S1904).

[0478] The current quality factor value according to an embodiment of the present invention is digital ping (Digital Ping ​​) It can also be measured before the stage, or can be measured immediately before the negotiation (re - negotiation) stage, and can also be measured periodically after the digital pinging stage.

[0479] If the comparison result, the current quality factor value (Q_current), is the same as or greater than the quality factor threshold value (Q_thres hod), the wireless power transmitter 1920 determines that no FO is detected and can transmit an ACK response to the wireless power receiver 1910 (S1905 ). At this time, the state of the wireless power transmitter 1920 can transition from the negotiation stage to the power transmission stage.

[0480] If the comparison result at the 1904 stage described above, the current quality factor value (Q_current), is less than the quality factor threshold value (Q_threshod), the wireless power transmitter 1920 determines that FO is detected and can transmit a NAK response to the wireless power receiver 1910 (S19 06). At this time, the state of the wireless power transmitter 1920 can transition from the negotiation stage to the selection stage.

[0481] According to still another embodiment of the present invention, a wireless power transmitter can obtain all of a reference quality factor value, a reference quality factor accuracy, and a reference quality factor degradation value through a plurality of FOD state packets. At this time, the wireless power transmitter can also determine a quality factor threshold value using at least one of the reference quality factor value, the reference quality factor accuracy, the reference quality factor degradation value, production, and measurement error.

[0482] As an example, the wireless power transmitter can determine the quality factor threshold value as the output value of a predetermined quality factor threshold value generation function using the reference quality factor value, the reference quality factor accuracy, and the reference quality factor degradation value as input variables. ​

[0483] According to yet another embodiment of the present invention, a wireless power transmitter transmits FOD status information via a plurality of FOD status packets. The quality factor value measured in the absence of foreign matter, the reference quality factor accuracy and the reference quality factor The power drop value can also be obtained from the wireless power receiver.

[0484] As an example, the wireless power transmitter may be configured to measure the quality factor from the quality factor value measured in the absence of foreign matter. The quality factor critical value is determined by subtracting the reference quality factor accuracy and the reference quality factor drop value. It is also possible.

[0485] As another example, the wireless power transmitter may measure a quality factor value measured in the absence of foreign matter, A function for generating a predetermined quality factor critical value using the reference quality factor accuracy and the reference quality factor drop value as input variables. The numerical output value may also be determined as a quality factor critical value.

[0486] FIG. 20 is a flowchart illustrating a method for detecting FO based on a quality factor value according to an embodiment of the present invention. This is a flow chart.

[0487] Referring to FIG. 20, the wireless power transmitter transmits a first frequency within a preset operating frequency band. The first quality factor value for the number of operating frequencies can be measured (S2001). The band can be preset to a frequency band between 100KHz and 210KHz. This is merely an example, and the setting and configuration of the wireless power transmitter or (and) the applied Please note that different operating frequency bands can be set depending on the standard used. Therefore, step S2001 is omitted and replaced by step S2003. The quality factor value for a particular frequency can be measured using the

[0488] The wireless power transmitter can measure a second quality factor value for a second frequency greater than a first frequency within an operating frequency band (S2003).

[0489] The wireless power transmitter can compare the magnitudes of the first quality factor value and the second quality factor value (S2005).

[0490] As an example, the first frequency can be the operating frequency for the maximum quality factor value of 12 to 11 g (O perating frequency for peak Q Factor val ue). For this purpose, in step S2005, the FOD status packet is received during the negotiation stage to confirm the first frequency, and the first quality factor value corresponding to the confirmed first frequency and the second quality factor value corresponding to a second frequency greater than the first frequency can be compared .

[0491] In yet another example, the first frequency can be 100 kHz. By determining the pre-agreed frequency between the wireless power transmitter and receiver to be 100 kHz and measuring and transmitting / receiving the reference quality factor value, the first frequency can be 100 kHz .

[0492] If, as a result of the comparison, the first quality factor value is greater than the second quality factor value, the wireless power transmitter can determine that the wireless power receiver is arranged aligned on the charging area (S2007) . Here, a high coupling coefficient between the transmission resonance coil (primary coil) and the reception resonance coil (secondary coil) can mean a well-aligned state .

[0493] If, as a result of the comparison in step 2005, the second quality factor value is greater than the first quality factor value, the wireless The power transmitter can determine that foreign substances are present on the charging area or that a misaligned wireless power receiver is placed. (S2009)

[0494] In another embodiment, if the comparison result at the 2005 stage shows that the second quality factor value is greater than the first quality factor value it is also possible to indicate only the presence of foreign substances in the charging area.

[0495] When foreign substances are present, the quality factor value corresponding to the second frequency can appear much larger than the quality factor value corresponding to the first frequency in the misalignment (unaligned) state. Small-impact foreign substances can have a quality factor value similar to that of unaligned ones, but the quality factor value measured when relatively large-impact foreign substances are present can show a relatively large difference from the quality factor value measured when an unaligned receiver is present.

[0496] According to an embodiment, if it is determined that a foreign substance or a misaligned wireless power receiver is placed, when power is currently being transmitted, the wireless power transmitter can interrupt the power transmission and output a predetermined alarm signal indicating that a foreign substance or a misaligned wireless power receiver is placed.

[0497] After outputting the alarm signal, the wireless power transmitter can wait for a certain period of time and then enter the selection stage to search for the receiver again. Considering the time it takes for the foreign substances placed in the charging area to be removed by the user or for the misaligned wireless power receiver to be properly repositioned by the user the waiting time before entering the selection stage can be determined.

[0498] ​​​​​​​​​​ A wireless power transmitter according to another embodiment of the present invention measures quality factor values for the first frequency and the second frequency before entering the selection stage, compares them, and can confirm whether foreign substances disposed in the charging area have been removed. If the removal of foreign substances is confirmed, the wireless power transmitter can enter the selection stage.

[0499] A wireless power transmitter according to still another embodiment of the present invention measures quality factor values for the first frequency and the second frequency before entering the selection stage, compares them, and can confirm whether a wireless power receiver is aligned. As a result of the confirmation, if the wireless power receiver is aligned, the wireless power transmitter can also enter the selection stage.

[0500] A wireless power transmitter according to one embodiment can perform the above-described steps 2701 to 2709 in the selection stage 210 of FIG. 2 described above, but this is only one embodiment, and it can also be performed at any stage before the negotiation stage 240, for example, any one of the selection stage 210, the ping stage 220, and the identification and configuration stage 230.

[0501] A wireless power transmitter according to another embodiment can also perform the above-described steps 2701 to 2709 in the power transmission stage 260 of FIG. 2 described above. In this case, while power control using an operating frequency adjustment is performed, the wireless power transmitter measures quality factor values for each frequency, compares them, and can also determine whether foreign substances are present in the charging area.

[0502] A wireless power transmitter according to still another embodiment of the present invention can determine (or acquire) a quality factor peak frequency at which the maximum quality factor value is measured within a preset operating frequency band. ​​​​​​​​​​​​​Performed (S2001, S2003). It is possible to search for the operating frequency at which the maximum quality factor value is measured by sweeping the frequency within a preset operating frequency band (or a specific frequency band) ). The wireless power transmitter receives an FOD Status packet including a reference peak frequency from the wireless power receiver, and compares the reference peak frequency with the acquired quality factor peak operating frequency to determine the presence or absence of foreign substances. It can be directly compared with the reference peak frequency, and the critical frequency can be determined in consideration of the transmission coil or design, product errors, etc., and the acquired quality factor peak operating frequency can also be compared with the critical frequency.

[0503] FIG. 21 is a block diagram for explaining the structure of an FO detection device corresponding to the embodiment of FIG. 20.

[0504] Referring to FIG. 21, the FO detection device 2100 can include a first quality factor measurement unit 2110, a second quality factor measurement unit 2120, a detection unit 2130, an alarm unit 2140, and a control unit 2150. In still other embodiments, the first quality factor measurement unit and the second quality factor measurement unit can be integrated into one module or device. In this case, the same measurement unit can measure the first quality factor value and the second quality factor value by adjusting the operating frequency of the control unit 2150. Alternatively, the same measurement unit can measure the maximum quality factor value by adjusting the operating frequency of the control unit, and store the quality factor peak operating frequency corresponding to the corresponding maximum quality factor value in the memory.

[0505] The first quality factor measurement unit 2110 can measure a first quality factor value corresponding to a first frequency within a preset operating frequency band.

[0506] The second quality factor measurement unit 2120 can measure the second quality factor value corresponding to the second frequency within a preset operating frequency band. Here, the second frequency is greater than the first frequency, and the frequency difference between the first frequency and the second frequency can be determined based on the bandwidth of the operating frequency band, but is not limited thereto. As an example, the first frequency and the second frequency can be determined as the lower limit frequency and the upper limit frequency of the operating frequency band, respectively.

[0507] The detection unit 2130 can determine whether a foreign substance exists in the charging area based on the first quality factor value and the second quality factor value. Alternatively, it can determine whether a foreign substance exists in the charging area based on the quality factor peak operating frequency and the reference quality factor peak operating frequency received from the wireless power receiving unit.

[0508] As an example, if the second quality factor value is greater than the first quality factor value, the detection unit 2130 can determine that a foreign substance is placed on the charging area or a misaligned wireless power receiver is placed. On the other hand, if the second quality factor value is smaller than the first quality factor value, the detection unit 2130 can determine that an aligned wireless power receiver is placed on the charging area.

[0509] As another example, if the second quality factor value is greater than a predetermined reference value than the first quality factor value, the detection unit 2930 can also determine that a foreign substance is placed on the charging area or a misaligned wireless power receiver is placed. On the other hand, if the first quality factor value is greater than the second quality factor value or the difference between the second quality factor value and the first quality factor value is smaller than a predetermined reference value, the detection unit 2130 can determine that an aligned wireless power receiver is placed on the charging area. ​

[0510] As yet another example, the detection unit 2130 may determine that a foreign substance is disposed or an unaligned wireless power receiver is disposed on the charging area based on the ratio of the change in the quality factor value due to the frequency change within the operating frequency band.

[0511] Here, the change ratio can be calculated by dividing the value obtained by subtracting the first quality factor value from the second quality factor value by the first quality factor value, but is not limited thereto, and any formula capable of calculating the change ratio of the quality factor value due to the frequency change is sufficient.

[0512] When the calculated change ratio is greater than 0 or equal to or greater than a first threshold value that is a predetermined positive number, the detection unit 2130 may determine that a foreign substance is disposed or an unaligned wireless power receiver is disposed on the charging area.

[0513] On the other hand, when the calculated change ratio is less than 0 or equal to or less than a second threshold value that is a predetermined negative number, the detection unit 2130 may determine that an aligned wireless power receiver is disposed on the charging area.

[0514] When the detection unit 2130 detects a foreign substance or an unaligned wireless power receiver, the detection unit 2130 may transmit the detection result to the control unit 2150.

[0515] The alarm unit 2140 may output, via an alarm means provided with a predetermined alarm signal for instructing that a foreign substance or an unaligned wireless power receiver exists on the charging area under the control of the control unit 2150. Here, the alarm means is a buzzer ( ​It can include a buzzer, an LED lamp, vibration, a liquid crystal display, etc., but is not limited to this. It is not limited to this.

[0516] According to one embodiment, if it is determined that a foreign substance or a misaligned wireless power receiver is arranged, when power is currently being transmitted, the power transmission unit 2160 shown in FIG. 20 described above is controlled to interrupt the power transmission, and the alarm unit 2140 is controlled to output a predetermined alarm signal indicating that a foreign substance or a misaligned wireless power receiver is arranged. If it is determined that a foreign substance or a misaligned wireless power receiver is arranged, when power is currently being transmitted, the power transmission unit 2160 shown in FIG. 20 described above is controlled to interrupt the power transmission, and the alarm unit 2140 is controlled to output a predetermined alarm signal indicating that a foreign substance or a misaligned wireless power receiver is arranged. If it is determined that a foreign substance or a misaligned wireless power receiver is arranged, when power is currently being transmitted, the power transmission unit 2160 shown in FIG. 20 described above is controlled to interrupt the power transmission, and the alarm unit 2140 is controlled to output a predetermined alarm signal indicating that a foreign substance or a misaligned wireless power receiver is arranged. If it is determined that a foreign substance or a misaligned wireless power receiver is arranged, when power is currently being transmitted, the power transmission unit 2160 shown in FIG. 20 described above is controlled to interrupt the power transmission, and the alarm unit 2140 is controlled to output a predetermined alarm signal indicating that a foreign substance or a misaligned wireless power receiver is arranged. It can be done.

[0517] After outputting the alarm signal, the control unit 2150 can wait for a certain period of time and then enter the selection stage to search for the receiver again. After outputting the alarm signal, the control unit 2150 can wait for a certain period of time and then enter the selection stage to search for the receiver again.

[0518] Considering the time it takes for the foreign substance arranged in the charging area to be removed by the user or for the misaligned wireless power receiver to be properly rearranged by the user, the waiting time before entering the selection stage can be determined. Considering the time it takes for the foreign substance arranged in the charging area to be removed by the user or for the misaligned wireless power receiver to be properly rearranged by the user, the waiting time before entering the selection stage can be determined. Considering the time it takes for the foreign substance arranged in the charging area to be removed by the user or for the misaligned wireless power receiver to be properly rearranged by the user, the waiting time before entering the selection stage can be determined.

[0519] According to another embodiment of the present invention, before entering the selection stage, the control unit 2150 controls the first and second quality factor measurement units 2110 and 2120 to measure the quality factor values for the first frequency and the second frequency, compares the measured first and second quality factor values, and can also confirm whether the foreign substance arranged in the charging area has been removed. If it is confirmed that the foreign substance has been removed, the control unit 2150 can enter the selection stage. According to another embodiment of the present invention, before entering the selection stage, the control unit 2150 controls the first and second quality factor measurement units 2110 and 2120 to measure the quality factor values for the first frequency and the second frequency, compares the measured first and second quality factor values, and can also confirm whether the foreign substance arranged in the charging area has been removed. If it is confirmed that the foreign substance has been removed, the control unit 2150 can enter the selection stage. According to another embodiment of the present invention, before entering the selection stage, the control unit 2150 controls the first and second quality factor measurement units 2110 and 2120 to measure the quality factor values for the first frequency and the second frequency, compares the measured first and second quality factor values, and can also confirm whether the foreign substance arranged in the charging area has been removed. If it is confirmed that the foreign substance has been removed, the control unit 2150 can enter the selection stage. According to another embodiment of the present invention, before entering the selection stage, the control unit 2150 controls the first and second quality factor measurement units 2110 and 2120 to measure the quality factor values for the first frequency and the second frequency, compares the measured first and second quality factor values, and can also confirm whether the foreign substance arranged in the charging area has been removed. If it is confirmed that the foreign substance has been removed, the control unit 2150 can enter the selection stage. According to another embodiment of the present invention, before entering the selection stage, the control unit 2150 controls the first and second quality factor measurement units 2110 and 2120 to measure the quality factor values for the first frequency and the second frequency, compares the measured first and second quality factor values, and can also confirm whether the foreign substance arranged in the charging area has been removed. If it is confirmed that the foreign substance has been removed, the control unit 2150 can enter the selection stage.

[0520] According to still another embodiment of the present invention, before entering the selection stage, the control unit 2150... Control to measure the quality factor values for the first frequency and the second frequency, and based on the measured first and second quality factor values, it is possible to confirm whether the wireless power receiver is properly aligned. As a result of the confirmation, if the wireless power receiver is properly aligned, the control unit 2150 can proceed to the selection stage.

[0521] In still another embodiment, the foreign substance detection stage is a selection stage, that is, it can be performed before the pinging stage. In this case, if a foreign substance is detected in the selection stage, the wireless power transmitter can maintain the selection stage without entering the pinging stage.

[0522] According to still another embodiment of the present invention, the control unit 2150, during power transmission to the wireless power receiver, that is, if a foreign substance is detected in the power transmission stage 260 of FIG. 2, it can temporarily interrupt the power transmission and output a predetermined alarm signal indicating that a foreign substance has been detected. If it is confirmed that the foreign substance detected during the output of the alarm signal has been removed from the charging area the control unit 2150 can control to resume power transmission.

[0523] FIG. 22 is a flowchart for explaining a FO detection method based on the quality factor value according to another embodiment of the present invention.

[0524] Referring to FIG. 22, the wireless power transmitter can divide a preset operating frequency band into a first frequency to an Nth frequency having a certain frequency interval (S2201). Here the operating frequency band can be roughly divided into a lower frequency band, an intermediate frequency band, and an upper frequency band. Here, the size of each frequency band can be changed according to the user's settings. ​​​​It should be noted that this can be done. As an example, when the operating frequency band is between 10 0 KHz and 210 KHz, and the frequency interval for dividing a specific frequency within the corresponding operating frequency band is set to 10 KHz, the corresponding operating frequency band can be divided into the 1st to 12th frequencies. Here, the 1st to 3rd frequencies are the lower frequency band (100 KH z to 130 KHz), the 4th to 9th frequencies are the intermediate frequency band (130 KHz to 180 KHz ), and the 10th to 12th frequencies can be divided into the upper frequency band (180 KHz to 210 KHz). This is just an example, and different operating frequency bands and frequency intervals can be set according to the settings and configuration modes of the corresponding wireless power transmitter, or (and) the applied standard specifications. It should be noted that this is just an example, and different operating frequency bands and frequency intervals can be set according to the settings and configuration modes of the corresponding wireless power transmitter, or (and) the applied standard specifications. or (and) the applied standard specifications. It should be noted that different operating frequency bands and frequency intervals can be set.

[0525] The wireless power transmitter can calculate the average value (a1) of the quality factor values (etc.) measured for the (N - K + 1)th to Nth frequencies included in the upper frequency band (S2203) .

[0526] In addition, the wireless power transmitter can calculate the average value (a2) of the quality factor values (etc.) measured for the 1st to Nth frequencies included in the upper frequency band (S2205).

[0527] The wireless power transmitter can compare the magnitudes of a1 and a2 (S2207).

[0528] As a comparison result, if the average quality factor value (a2) for the lower frequency band is greater than the average quality factor value (a1) for the upper frequency band, the wireless power transmitter can determine that a wireless power receiver aligned on the charging area is arranged (S2209). Here, the transmission resonance ​​​A state in which the coupling coefficient between the coil (primary coil) and the reception resonance coil (secondary coil) is high is well aligned can be said to be the state.

[0529] Based on the comparison result in the above-described step 2207, if a2 is the same as or smaller than a1, the wireless power transmitter can determine that a foreign substance or a misaligned wireless power receiver is arranged on the charging area (S2211).

[0530] The wireless power transmitter can output a predetermined alarm signal indicating that a foreign substance or a misaligned wireless power receiver is arranged on the charging area (S2213).

[0531] The wireless power transmitter according to an embodiment can perform the above-described steps 2201 to 2213 in the selection step 210 of FIG. 2 described above, but this is only one embodiment, and any step before the negotiation step 240, for example, the selection step 210, the ping step 220, and the identification and configuration step 230 can also be performed at any one of the steps. According to another embodiment, the wireless power transmitter can also perform the above-described steps 2201 to 2213 in the power transmission step 260 of FIG. 2. In this case, the wireless power transmitter can measure the quality factor value for each frequency while performing power control by adjusting the operating frequency. Also, the wireless power transmitter can calculate the average quality factor value of the upper frequency band and the average quality factor value of the lower frequency band using the measured quality factor values for each frequency, and then compare these to determine whether a foreign substance exists in the charging area

[0532] In the embodiment of FIG. 21 above, simply the average quality factor value (a1) of the upper frequency band and the lower frequency frequency After calculating the average quality factor value of the upper frequency band and the average quality factor value of the lower frequency band, the wireless power transmitter can compare these to determine whether a foreign substance exists in the charging area using the measured quality factor values for each frequency, and then compare these to determine whether a foreign substance exists in the charging area After calculating the average quality factor value of the upper frequency band and the average quality factor value of the lower frequency band using the measured quality factor values for each frequency, the wireless power transmitter can compare these to determine whether a foreign substance exists in the charging area can also be determined.

[0533] In the embodiment of FIG. 21 above, simply the average quality factor value (a1) of the upper frequency band and the lower frequency It is determined whether there is a foreign substance by comparing the magnitudes of the average values (a2) of the quality factors of the bands. Although it has been described, this is only one example, and the wireless power transmitter according to other examples of the present invention determines whether a foreign substance or a misaligned wireless power receiver is placed in the charging area based not only on whether the average value of the quality factor increases or decreases due to a frequency change but also on the amount of increase / decrease in the average value of the quality factor. As an example, when the value obtained by subtracting a1 from a2 is negative and the absolute value of the difference value between a2 and a1 exceeds a predetermined critical value, the wireless power transmitter can determine that a foreign substance or a misaligned wireless power receiver is placed on the charging area.

[0534] FIG. 23 is a block diagram for explaining the structure of the FO detection device corresponding to the embodiment of FIG. 22.

[0535] Referring to FIG. 23, the FO detection device 2300 can include an operating frequency division unit 2310, a quality factor measurement unit 2320, an average calculation unit 2330, a detection unit 2340, an alarm unit 2350, and a control unit 2360.

[0536] The operating frequency division unit 2310 divides a predefined operating frequency band at a predetermined frequency interval and divides it into first to Nth frequencies at which the quality factor value is to be measured, and the divided frequencies can be divided into a lower frequency band, an intermediate frequency band, and an upper frequency band. Here, the lower frequency band and the number of measurement target frequencies included in the lower frequency band can be predefined and maintained in a predetermined recording area. The operating frequency band, the frequency interval, the number of measurement target frequencies included in the lower / upper frequency bands, etc. are predefined user interfaces mounted on the wireless power transmitter It should be noted that the base means or (and) the external device linked to the corresponding wireless power transmitter via a wired or wireless communication network can be changed by the server.

[0537] The quality factor measurement unit 2320 can measure the quality factor values corresponding to the first to Nth frequencies. The quality factor measurement unit 2340 according to an embodiment can also measure only the quality factor values for the measurement target frequencies included in the lower frequency band and the upper frequency band.

[0538] The average calculation unit 2330 can calculate the average value (a2) of the quality factor values (etc.) measured for the lower frequency band and the average value (a1) of the quality factor values (etc.) measured for the upper frequency band.

[0539] The detection unit 2340 can detect foreign substances or misaligned wireless power receivers arranged on the charging area based on a1 and a2, and transmit the detection result to the control unit 2360. As an example, when the value obtained by subtracting a2 from a1 is a positive number, that is, when the average of the quality factor values increases as the frequency within the operating frequency band increases, it can be determined that there are foreign substances or misaligned wireless power receivers on the charging area. On the other hand, when the value obtained by subtracting a2 from a1 is a negative number, that is, when the average of the quality factor values decreases as the frequency within the operating frequency band increases, it can be determined that there are aligned wireless power receivers on the charging area.

[0540] As another example, the detection unit 2340 considers not only the increase or decrease of the average quality factor value due to the frequency change within the operating frequency band, but also the increase amount / decrease amount of the average quality factor value. It is also possible to determine whether a foreign substance or a misaligned wireless power receiver is disposed in the charging area. As an example, when the value obtained by subtracting a1 from a2 is negative and the absolute value of the difference value between a2 and a1 exceeds a predetermined threshold value, the wireless power transmitter can determine that a foreign substance or a misaligned wireless power receiver is disposed on the charging area.

[0541] The alarm unit 2350 can output, via an alarm means provided with a predetermined alarm signal for instructing, under the control of the control unit 2360, that a foreign substance exists on the charging area or that a misaligned wireless power receiver exists. Here, the alarm means can include, but is not limited to, a buzzer (buzzer), an LED lamp, vibration, a liquid crystal display, etc. (buzzer), an LED lamp, vibration, a liquid crystal display, etc., but is not limited thereto.

[0542] FIGS. 24A to 24D are experimental result graphs for explaining the logical basis of the embodiments of FIGS. 20 to 23.

[0543] Referring to reference numeral 2411 in FIG. 24A, when only the first receiver is disposed on the charging area, the quality factor value measured by the wireless power transmitter indicates that it decreases as the frequency within the operating frequency band (100 KHz to 210 KHz) increases. On the other hand, referring to reference numeral 2412, when the first receiver and FO4, which is a foreign substance, are disposed on the charging area, the quality factor value measured by the wireless power transmitter indicates that it increases as the frequency within the operating frequency band increases.

[0544] Referring to reference numeral 2413, when only the first receiver is disposed in the charging area, the quality factor value measured at an operating frequency of 100 KHz is 44, and the measurement at an operating frequency of 210 KHz is It can be seen that the obtained quality factor value is 40. On the other hand, when a FO4, which is a foreign substance different from the first receiver, is arranged in the charging area, the quality factor value measured at an operating frequency of 100 KHz is 27.1 and the quality factor value measured at an operating frequency of 210 KHz is found to be 30.65 . Here, FO4 means a foreign substance of a standard specification defined in the WPC standard .

[0545] The experimental results shown in FIG. 24a described above indicate that when the wireless power receivers are arranged in alignment in the charging area, the quality factor value decreases as the frequency within the operating frequency band increases. However, when a foreign substance is arranged in the charging area, the quality factor value increases as the frequency within the operating frequency band increases . . .

[0546] FIG. 24b shows the experimental results for a second receiver generated by a manufacturer different from that of the first receiver in FIG. 24a .

[0547] Referring to reference numeral 2421 in FIG. 24b, when only the second receiver is arranged on the charging area, the quality factor value measured by the wireless power transmitter indicates that the quality factor value decreases as the frequency within the operating frequency band (100 KHz to 210 KHz) increases. On the other hand, referring to reference numeral 2422, when the second receiver and a foreign substance FO4 are arranged on the charging area, the quality factor value measured by the wireless power transmitter indicates that the quality factor value increases as the frequency within the operating frequency band increases . . . .

[0548] Actually, referring to reference numeral 2423, when only the second receiver is arranged in the charging area, the quality factor value measured at an operating frequency of 100 KHz is 39.5, and at an operating frequency of 210 KHz It can be seen that the quality factor value measured at KHz is 31.1. On the other hand, when the second receiver and the foreign substance FO4 are arranged in the charging area, the quality factor value measured at an operating frequency of 100 KHz is 24.9, and the quality factor value measured at an operating frequency of 210 KHz is 26.1 It can be seen that.

[0549] The experimental results shown in FIG. 24b described above are the same as the experimental results of FIG. 24a. When the wireless power receivers are arranged in alignment in the charging area, the quality factor value decreases as the frequency within the operating frequency band increases. However, when a foreign substance is arranged in the charging area, it shows that the quality factor value increases as the frequency within the operating frequency band increases. As the frequency within the operating frequency band increases, the quality factor value decreases. However, when a foreign substance is arranged in the charging area, it shows that the quality factor value increases as the frequency within the operating frequency band increases. As the frequency within the operating frequency band increases, the quality factor value decreases. However, when a foreign substance is arranged in the charging area, it shows that the quality factor value increases as the frequency within the operating frequency band increases. As the frequency within the operating frequency band increases, the quality factor value increases.

[0550] FIG. 24c shows the quality factor values measured for the foreign substance FO4 and the dime defined as a standard in the operating frequency band. It shows the quality factor values measured for the foreign substance FO4 and the dime defined as a standard in the operating frequency band.

[0551] Reference numerals 2431 and 2432 in FIG. 24c respectively show the change patterns of the quality factor values measured for the dime and FO4. As shown by reference numerals 2431 and 2432, when a foreign substance that is not a wireless power receiver is placed in the charging area, it can be seen that the quality factor value increases as the frequency within the operating frequency band increases. As shown by reference numerals 2431 and 2432, when a foreign substance that is not a wireless power receiver is placed in the charging area, it can be seen that the quality factor value increases as the frequency within the operating frequency band increases. When a foreign substance that is not a wireless power receiver is placed in the charging area, it can be seen that the quality factor value increases as the frequency within the operating frequency band increases. When a foreign substance that is not a wireless power receiver is placed in the charging area, it can be seen that the quality factor value increases as the frequency within the operating frequency band increases.

[0552] However, in the case of the dime, it shows that some of the quality factor values measured in the intermediate frequency band are larger than the quality factor values measured in the upper limit frequency band. Therefore, in order to minimize the occurrence of incorrect judgments due to incorrect measurement results, as described in FIGS. 22 and 23 above, it is possible to determine the presence or absence of a foreign substance based on the average quality factor value calculated for each of the lower limit frequency band and the upper limit frequency band. it is possible to determine the presence or absence of a foreign substance based on the average quality factor value calculated for each of the lower limit frequency band and the upper limit frequency band. s. It is possible to determine the presence or absence of a foreign substance based on the average quality factor value calculated for each of the lower limit frequency band and the upper limit frequency band.

[0553] Figure 24d shows the experimental results for a third receiver sold by a manufacturer different from the aforementioned first and second receivers.

[0554] Referring to reference numeral 2441 in Figure 24d, in the case where only the third receiver is placed in the charging area, the quality factor value decreases as the frequency increases. However, as shown by reference numerals 2442 and 2443, when a foreign substance, such as FO4 or a 10 - cent coin, is further placed in the charging area, it shows that the quality factor value increases as the frequency increases.

[0555] Figure 24e shows the experimental results for a standard wireless power transmitter and a standard wireless power receiver module used for product certification.

[0556] Referring to reference numeral 2452 in Figure 24e, when a standard wireless power receiver module is placed on the standard wireless power transmitter, it can be seen that the quality factor value decreases as the frequency within the operating frequency band increases. Of course, as shown by reference numeral 2451, even when nothing is placed in the charging area of the standard wireless power transmitter, it can be seen that the quality factor value decreases as the frequency within the operating frequency band increases. However, referring to reference numeral 2453, it can be seen that the quality factor value measured with a standard wireless power receiver module placed in the charging area of the standard wireless power transmitter is overall slightly lower than when nothing is placed in the charging area.

[0557] Figure 25 is a diagram for explaining the relationship between the quality factor value and the maximum quality factor peak frequency due to the arrangement of a wireless power receiver and a foreign substance in the charging area of a wireless power transmitter.

[0558] ​​​​​​​​​​ The table shown in FIG. 25 shows how much the maximum quality factor peak frequency shifts when only the wireless power receiver is placed in the charging area and when the wireless power receiver and a foreign substance are placed in the charging area together. At this time, the presence or absence of a foreign substance can be determined using the maximum quality factor peak frequency. The wireless power transmitter can receive information about the reference quality factor peak frequency from the wireless power receiver and determine the critical frequency based on the received information. Here, the critical frequency can be determined in consideration of coil design, circuit characteristics, errors, etc. By comparing the critical frequency with the peak frequency in FIG. 25, the wireless power transmitter can determine the presence or absence of a foreign substance.

[0559]

[0560] FIG. 26 is a diagram for explaining a state transition process for foreign substance detection in a foreign substance detection device according to an embodiment of the present invention.

[0561] Referring to FIG. 26, if an object is detected in the selection stage 2610, the foreign substance detection device can measure the quality factor values of the resonant circuit for a plurality of operating frequencies (S2601). Here, the number of operating frequencies for which the quality factor value is measured can be 2 to 6, but is not limited thereto, and may be a larger number. The operating frequency values for which the quality factor value is measured are values selected within a predefined operating frequency range and can be selected to have a certain frequency interval. As an example, when the operating frequency range of the foreign substance detection device is from 100 KHz to 220 KHz and the number of operating frequencies to be measured is 5, the quality factor value is measured ​​​​​​​​​​​​​​The set operating frequency values can be 100 KHz, 130 KHz, 160 KHz, 190 KHz, and 220 KHz.

[0562] The foreign substance detection device can determine whether a foreign substance is placed in the charging area based on the measured quality factor value, that is, can determine the presence or absence of a foreign substance (S2602).

[0563] As an example, if the quality factor value increases as the operating frequency increases, the foreign substance detection device can determine that a foreign substance is present in the charging area. On the other hand, if the quality factor value decreases as the operating frequency increases, the foreign substance detection device can determine that no foreign substance is present in the charging area.

[0564] As another example, the foreign substance detection device calculates the change amount of the quality factor value with respect to adjacent operating frequencies, and if the average of the calculated change amounts exceeds a predetermined reference value (for example, the reference value can be 0, but is not limited to this), it can be determined that a foreign substance is present in the charging area. Here, the adjacent operating frequencies mean the two closest operating frequencies among the operating frequencies at which the quality factor value is measured.

[0565] As yet another example, the foreign substance detection device calculates the slope of the quality factor value with respect to adjacent operating frequencies, and if the average of the calculated slopes exceeds a predetermined first reference value, it can be determined that a foreign substance is present in the charging area. On the other hand, if the average of the calculated slopes is less than or equal to a predetermined second reference value, it can be determined that no foreign substance is present in the charging area. Here, the first reference value and the second reference value can have different values. In this case, the first reference value is greater than the second reference value.

[0566] Once the determination of the presence or absence of foreign substances is complete, the foreign substance detection device can enter the ping stage 2620. It can enter.

[0567] In the ping stage 2620, the foreign substance detection device can periodically transmit a predetermined power signal for identifying the wireless power receiver, such as a digital ping. It can be transmitted periodically.

[0568] If the signal strength indicator is received in the ping stage 2620, the foreign substance detection device enters the identification and configuration stage 2630 to identify the wireless power receiver and can set various configuration parameters for the identified wireless power receiver. It can enter the identification and configuration stage 2630 to identify the wireless power receiver and set various configuration parameters for the identified wireless power receiver. It can set various configuration parameters.

[0569] Once the identification and configuration of the wireless power receiver are complete, the foreign substance detection device enters the negotiation stage 2640 and can receive a foreign object detection status packet (FOD Status Packet) from the identified wireless power receiver (S2603). Here, the foreign object detection status packet can include a reference quality factor value. It can receive a foreign object detection status packet from the identified wireless power receiver. Here, the foreign object detection status packet can include a reference quality factor value. It can include a reference quality factor value.

[0570] Based on the determination result of the above-mentioned step 2602, the foreign substance detection device can transmit a NAK response signal or an ACK response signal to the identified wireless power receiver (S2604). At this time, the foreign substance detection device does not necessarily have to determine a threshold value (or threshold range) for determining the presence or absence of foreign substances based on the received foreign object detection status packet. If the determination result of the above-mentioned step 2602 indicates the presence of foreign substances, after transmitting the NAK response signal to the identified wireless power receiver, the foreign substance detection device can transition to the selection stage 2610. At this time, the foreign substance detection device can interrupt the power transmission and output a predetermined warning alarm indicating that foreign substances have been detected. It can transmit a NAK response signal or an ACK response signal to the identified wireless power receiver. At this time, based on the received foreign object detection status packet, the foreign substance detection device does not necessarily have to determine a threshold value (or threshold range) for determining the presence or absence of foreign substances. Based on the received foreign object detection status packet, the foreign substance detection device does not necessarily have to determine a threshold value (or threshold range) for determining the presence or absence of foreign substances. If the determination result of the above-mentioned step 2602 indicates the presence of foreign substances, after transmitting the NAK response signal to the identified wireless power receiver, the foreign substance detection device can transition to the selection stage 2610. After transmitting the NAK response signal to the identified wireless power receiver, the foreign substance detection device can transition to the selection stage 2610. At this time, the foreign substance detection device can interrupt the power transmission and output a predetermined warning alarm indicating that foreign substances have been detected. It can output a predetermined warning alarm.

[0571] As an example, when the determination result at the 2602 stage indicates that there is no foreign substance, the foreign substance detection device can transition to the power transmission stage 2650 after transmitting an ACK response signal. As another example, when the determination result at the 2602 stage indicates that there is no foreign substance, the foreign substance detection device can also transition to the power transmission stage 2650 via the correction stage 250 of FIG. 2 described above.

[0572] The foreign substance detection device can enter the power transmission stage 2650 and start wireless charging for the corresponding wireless power receiver.

[0573] The foreign substance detection device that has transitioned to the selection stage 2610 due to foreign substance detection periodically measures the quality factor value of the resonance circuit for a plurality of operating frequencies, and can also determine whether the foreign substance has been removed based on the measured quality factor value. If the determination result indicates that the foreign substance has been removed, the foreign substance detection device can enter the power transmission stage 2650 and resume power transmission to the corresponding wireless power receiver. On the other hand, if the foreign substance detected within a predetermined time after transitioning to the selection stage 2610 due to foreign substance detection has not been removed, the foreign substance detection device can output a predetermined warning alarm indicating that the detected foreign substance has not been removed. removed. removed.

[0574] The foreign substance detection device according to another embodiment of the present invention can also transmit a predetermined foreign substance presence status packet (FO Presence Status Packet) including foreign substance status information (FO Status Information) corresponding to the determination result at the 2601 stage to the corresponding wireless power receiver. As an example, if the foreign substance status information is '0', presence power receiver. As an example, if the foreign substance status information is '0', It means that no foreign substance was detected. If it is '1', it means that a foreign substance was detected. It can be done, but is not limited to this.

[0575] In yet another embodiment, the S2603 packet can be omitted.

[0576] FIG. 27 is a diagram for explaining the message structure of the FOD status packet according to another embodiment of the present invention. It is a figure for the purpose.

[0577] Referring to FIG. 27, the FOD status packet message 2700 can have a length of 2 bytes, a first data 2701 field with a length of 6 bits, a mode ( Mode) 2702 field with a length of 2 bits, and a reference quality factor value (Reference Quality Factor Value) 2703 field with a length of 1 byte. It can be included. It can be.

[0578] As shown by the reference numeral 2704, if the mode 2702 field is set to the binary number '00', all bits of the first data 2701 field are recorded as 0, and the reference quality factor value recorded in the 2703 field is the reference quality factor value determined by measuring in a state where the power supply of the corresponding radio power receiver is OFF. On the other hand, if the mode 2702 field is set to the binary number '01', the quality factor value measured in a state where the power supply of the corresponding radio power receiver is OFF is recorded in the first data 2701 field, which is 5% lower than the reference quality factor value. The operating frequency can be recorded. The reference quality factor value recorded in the 2703 field can be the reference quality factor value determined by measuring in a state where the power supply of the corresponding radio power receiver is OFF. As an example Referring to FIG. 20 above, the reference quality factor value of the receiver 2 is such that the operating frequency is 100K When set, the quality factor value measured in a state where the power supply of the corresponding radio power receiver is OFF can be recorded in the first data 2701 field, which is 5% lower than the reference quality factor value. The reference quality factor value recorded in the 2703 field can be the reference quality factor value determined by measuring in a state where the power supply of the corresponding radio power receiver is OFF. For example When referring to FIG. 20, the reference quality factor value of the receiver 2 is such that the operating frequency is 100K and the quality factor value measured in a state where the power supply of the corresponding radio power receiver is OFF can be recorded in the first data 2701 field, which is 5% lower than the reference quality factor value. The reference quality factor value recorded in the 2703 field can be the reference quality factor value determined by measuring in a state where the power supply of the corresponding radio power receiver is OFF. For example When referring to FIG. 20, the reference quality factor value of the receiver 2 is such that the operating frequency is 100K and the reference quality factor value of the receiver 2 is measured in a state where the power supply of the receiver 2 is OFF, and the reference quality factor value determined by the measurement is recorded in the reference quality factor value 2703 field. It can be 39.5 measured at Hz. Here, the quality factor value 5% lower than the reference quality factor value is 37.525. Therefore, the operating frequency having a quality factor value 5% lower than the reference quality factor value

[0579] In the embodiment of FIG. 27 described above, it is described that a value corresponding to the operating frequency having a quality factor value 5% lower than the reference quality factor value is recorded in the first data 2701 field. However, this is only an example, and other values other than 5%, for example 7 %, can be set according to the design of those skilled in the art. % can also be set.

[0580] FIG. 28 is a diagram for explaining a state transition process for foreign substance detection in a foreign substance detection device according to an embodiment of the present invention. is a diagram for explaining.

[0581] Referring to FIG. 28, when an object is sensed in the selection stage 2810, the foreign substance detection device can measure the quality factor values of resonance circuits for a plurality of operating frequencies including the lower limit frequency of the operating frequency band (S2801). Here, the number of operating frequencies at which the quality factor values are measured can be 2 to 8, but is not limited thereto, and may be a larger number. The operating frequencies at which the quality factor values are measured are values selected within a predefined operating frequency range and can be selected to have a certain frequency interval, but are not limited thereto, and can also be arbitrarily selected within the operating frequency range. As an example, the operating frequency range of the foreign substance detection device can be from 100 KHz to 220 KHz. At this time, the lower limit frequency is 100 K Hz, and when the number of operating frequencies to be measured is 7, the operating frequencies at which the quality factor values are measured range can be arbitrarily selected within the operating frequency range. As an example, the operating frequency range of the foreign substance detection device can be from 100 KHz to 220 KHz. At this time, the lower limit frequency is 100 K Hz, and when the number of operating frequencies to be measured is 7, the operating The frequency values can be 100 KHz, 120 KHz, 140 KHz, 160 KHz, 180 KHz, 200 KHz, and 220 KHz.

[0582] The foreign substance detection device can record the quality factor values measured for each operating frequency in a predetermined recording area. That is possible.

[0583] If the measurement of the quality factor value is completed, the foreign substance detection device can enter the ping stage 2820. That is possible.

[0584] In the ping stage 2820, the foreign substance detection device can periodically transmit a predetermined power signal, such as a digital ping, for identifying the radio power receiver. That is possible.

[0585] If a signal strength indicator is received in the ping stage 2820, the foreign substance detection device enters the identification and configuration stage 283, identifies the radio power receiver, and can set various configuration parameters for the identified radio power receiver. That is possible.

[0586] If the identification and configuration of the radio power receiver are completed, the foreign substance detection device enters the negotiation stage 284 0, and can receive a foreign object detection status packet (FOD Stat us Packet) from the identified radio power receiver (S2802). Here, the foreign object detection status packet can include information about an operating frequency having a quality factor value 5% lower than the reference quality factor value (hereinafter, for the sake of convenience of explanation, referred to as the 'critical frequency').

[0587] The foreign substance detection device compares the quality factor value (Q1) corresponding to the lower limit frequency measured in the above-described 2801 stage with the quality factor value (Q2) measured at an operating frequency higher than the critical frequency. It is possible to determine the presence or absence of a foreign substance (S2803). Here, Q2 can be the quality factor value having the maximum value among the quality factor values measured at an operating frequency higher than the critical frequency. .

[0588] If Q2 is greater than Q1, the foreign substance detection device can determine that a foreign substance is disposed in the charging area. On the other hand, if Q2 is smaller than Q1, the foreign substance detection device can determine that no foreign substance is disposed in the charging area.

[0589] The foreign substance detection device according to another embodiment can determine (or estimate) the quality factor value corresponding to the critical frequency based on the quality factor values for each operating frequency measured in step 2801. For example, when the critical frequency is included among the plurality of operating frequencies used for measuring the quality factor value in step 2801, the quality factor value measured at the corresponding operating frequency becomes the quality factor value measured at the critical frequency. However, when the critical frequency is not included among the plurality of operating frequencies used for measuring the quality factor value in step 2801, the quality factor value corresponding to the critical frequency can also be estimated based on at least one quality factor value measured at the operating frequency closest to the critical frequency. As an example, a linear function can be derived using the quality factor values measured at the two operating frequencies closest to the critical frequency, and the critical frequency can be substituted into the derived linear function to estimate the quality factor value corresponding to the critical frequency, but the present invention is not limited thereto.

[0590] The foreign substance detection device can transmit a NAK response signal or an ACK response signal to the identified radio power receiver according to the determination result in step 2803 described above (S2804). ​At this time, the foreign matter detection device does not need to determine a threshold value (or threshold range) for determining the presence or absence of foreign matter based on the received foreign matter detection state packet. Based on the determination result in step 2803, if foreign matter is present, after the foreign matter detection device transmits a NAK response signal to the identified wireless power receiver, it can transition to the selection step 2810. At this time, the foreign matter detection device can interrupt power transmission and output a predetermined warning alarm indicating that foreign matter has been detected. As an example, based on the determination result in step 2802, if no foreign matter is present, after the foreign matter detection device transmits an ACK response signal, it can transition to the power transmission step 2850. As another example, based on the determination result in step 2803, if no foreign matter is present, the foreign matter detection device can also transition to the power transmission step 2850 through the correction step 250 of FIG. 2 described above. The foreign matter detection device can enter the power transmission step 2850 and start wireless charging for the corresponding wireless power receiver. The foreign matter detection device that has transitioned to the selection step 2810 due to foreign matter detection can periodically measure the quality factor value of the resonant circuit for a plurality of operating frequencies, and based on the measured quality factor value, determine whether the foreign matter has been removed. If the determination result is that the foreign matter has been removed, the foreign matter detection device can enter the power transmission step 2850 and resume power transmission to the corresponding wireless power receiver. On the other hand, if the foreign matter detected within a predetermined time after transitioning to the selection step 2810 due to foreign matter detection has not been removed, the foreign matter detection device determines that the detected foreign matter has been removed.

[0591]

[0592]

[0593] It is possible to output a predetermined warning alarm indicating that something has not occurred.

[0594] The foreign substance detection device according to another embodiment of the present invention corresponds to the determination result of the 2801 step. A predetermined foreign substance presence status packet including foreign substance status information (FO Status Information) can also be further transmitted to the corresponding radio receiver. As an example, if the foreign substance status information is '0', it means that no foreign substance has been detected, and if it is '1', it means that a foreign substance has been detected. This can be done, but is not limited thereto.

[0595] FIG. 29 is a diagram for explaining a state transition process for foreign substance detection in a foreign substance detection device according to an embodiment of the present invention.

[0596] If an object is detected in the selection step 2910, the foreign substance detection device according to this embodiment can measure the quality factor value of the resonance circuit for a plurality of operating frequencies (S2901).

[0597] If an FOD status packet including a critical frequency is received in the negotiation step, the foreign substance detection device can identify at least two or more operating frequencies equal to or greater than the critical frequency, and extract the quality factor values measured at the identified operating frequencies (S2903).

[0598] The foreign substance detection device can compare the quality factor values corresponding to each of the operating frequencies equal to or greater than the critical frequency to determine the presence or absence of a foreign substance (S2904). As an example, when the quality factor value increases as the operating frequency increases, the foreign substance detection device is full. It can be determined that there is a foreign substance in the charging area. On the other hand, when the quality factor value decreases as the operating frequency increases, the foreign substance detection device can determine that there is no foreign substance in the charging area. When the quality factor value decreases as the operating frequency increases, the foreign substance detection device can determine that there is no foreign substance in the charging area. It can be determined that there is no foreign substance in the charging area.

[0599] According to still another embodiment of the present invention, when an object is sensed in the selection stage, the foreign substance detection device can also scan the quality factor value within the operating frequency band. According to still another embodiment of the present invention, when an object is sensed in the selection stage, the foreign substance detection device can also scan the quality factor value within the operating frequency band.

[0600] Here, the operating frequency band can be divided into a plurality of lower frequency regions that do not overlap with each other. As an example, the operating frequency band can be divided into a first frequency region including the lower limit frequency and a second frequency region including the upper limit frequency. Here, the operating frequency band can be divided into a plurality of lower frequency regions that do not overlap with each other. As an example, the operating frequency band can be divided into a first frequency region including the lower limit frequency and a second frequency region including the upper limit frequency. Here, the operating frequency band can be divided into a plurality of lower frequency regions that do not overlap with each other. As an example, the operating frequency band can be divided into a first frequency region including the lower limit frequency and a second frequency region including the upper limit frequency.

[0601] As an example, when the operating frequency band is 100 KHz to 200 KHz, the first frequency region can be 100 KHz to 150 KHz including the lower limit frequency of 100 KHz, and the second frequency region can be 151 KHz to 200 KHz including the upper limit frequency of 200 KHz. As an example, when the operating frequency band is 100 KHz to 200 KHz, the first frequency region can be 100 KHz to 150 KHz including the lower limit frequency of 100 KHz, and the second frequency region can be 151 KHz to 200 KHz including the upper limit frequency of 200 KHz. As an example, when the operating frequency band is 100 KHz to 200 KHz, the first frequency region can be 100 KHz to 150 KHz including the lower limit frequency of 100 KHz, and the second frequency region can be 151 KHz to 200 KHz including the upper limit frequency of 200 KHz.

[0602] The foreign substance detection device can scan the quality factor value while changing the frequency within the first frequency region in a certain frequency unit, and identify the operating frequency (first frequency) at which the highest quality factor value is measured. The foreign substance detection device can scan the quality factor value while changing the frequency within the first frequency region in a certain frequency unit, and identify the operating frequency (first frequency) at which the highest quality factor value is measured. In addition, the foreign substance detection device can scan the quality factor value while changing the frequency within the second frequency region, and identify the operating frequency (second frequency) at which the highest quality factor value is measured. In addition, the foreign substance detection device can scan the quality factor value while changing the frequency within the second frequency region, and identify the operating frequency (second frequency) at which the highest quality factor value is measured. The foreign substance detection device can compare the quality factor value (Q4) corresponding to the first frequency with the quality factor value (Q5) corresponding to the second frequency to determine whether there is a foreign substance in the charging area. The foreign substance detection device can compare the quality factor value (Q4) corresponding to the first frequency with the quality factor value (Q5) corresponding to the second frequency to determine whether there is a foreign substance in the charging area. As an example, if Q5 is greater than Q4, the foreign substance detection device determines that there is a foreign substance. It can be determined that it exists. On the contrary, if Q5 is smaller than Q4, the foreign substance detection device can determine that no foreign substance exists.

[0603] FIG. 30 illustrates the message structure of an FOD status packet according to still another embodiment of the present invention. It is a diagram for doing.

[0604] Referring to FIG. 30, the FOD status packet message 3000 can have a length of 2 bytes, a reserved 3001 field with a length of 6 bits, a mode (Mode) 3002 field with a length of 2 bits, a first data 3003 field, and a second data field 30 04 can be included. In the embodiment of FIG. 30 described above, the size of the first data 3003 field is 3 bits, and the size of the field of the second data 3004 is 5 bits is shown as such, but this is only an example and is not limited thereto. All bits of the reserved 3001 field are recorded as 0.

[0605] As shown by the reference numeral 3005, if the mode 3002 field is set to the binary number '00', the reference quality factor value determined by measuring in a state where the power of the corresponding wireless power receiver is OFF is recorded in the first data 3003 field and the second data 3004 field.

[0605] 9] On the other hand, if the mode 3002 field is set to the binary number '01', critical frequency information is recorded in the first data 3003 field, and ratio information of the quality factor value corresponding to the critical frequency with respect to the quality factor value corresponding to the lower limit frequency is recorded in the second data 3004 field.

[0606] ​​​​​The method according to the above-described embodiment is made into a program for execution by a computer and can be stored in a computer-readable recording medium. Examples of the computer-readable recording medium include ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage devices, etc., and also include those embodied in the form of a carrier wave (for example, transmission via the Internet ).

[0607] The computer-readable recording medium is distributed to computer systems connected via a network and the code that can be read by a computer can be stored and executed in a distributed manner . And the functional program, code, and code segment for embodying the above-described method can be easily deduced by a programmer in the technical field to which the embodiment belongs .

[0608] It is obvious to those skilled in the art that the present invention can be embodied in other specific forms without departing from the spirit and essential features of the present invention .

[0609] Therefore, the above detailed description should not be construed restrictively in all aspects, and should be considered as exemplary . The scope of the present invention should be determined by a reasonable interpretation of the appended claims, and all modifications within the equivalent scope of the present invention are included in the scope of the present invention .

Industrial Applicability

[0610] The foreign substance detection method according to the embodiment uses a quality factor value to detect foreign substances located between a wireless power transmitter and a wireless power transmitter before the ping stage, during the negotiation stage, and during the power transmission stage, and is applicable to a wireless charging system​

Claims

1. In a power transmission method of a wireless power transmitter, a packet receiving step of receiving an FOD status packet from a wireless power receiver; a step of determining whether a foreign substance exists in a charging area of the wireless power transmitter based on the FOD status packet; and a step of transmitting a response signal indicating whether the foreign substance exists in the charging area of the wireless power transmitter to the wireless power receiver based on the result of the determination, wherein the response signal is determined using a measured peak frequency of a power signal transmitted by the wireless power transmitter and a reference peak frequency which is a value measured in a state where no foreign substance is disposed in the charging area included in the FOD status packet received from the wireless power receiver, the FOD status packet includes a preamble, a header, a message, and a checksum for identifying whether an error has occurred in the packet, the header is for identifying the type of the packet, the FOD status packet has a length of 2 bytes, 1 byte of the FOD status packet includes a reserved field having a length of 6 bits and a mode field having a length of 2 bits, the mode field indicates whether the FOD status packet includes information regarding a reference peak frequency of the wireless power receiver, a power transmission method.

2. The power transmission method according to claim 1, wherein the size of the message included in the packet is identified based on a value of the header.

3. The power transmission method according to claim 1, further including a step of receiving at least one of a signal strength packet, an end power transfer packet, a power control hold-off packet, a configuration packet, an identification packet for transmitting receiver identification information, an extended identification packet, a general request packet, a special request packet, a control error packet, a renegotiation packet, a 24-bit received power packet, an 8-bit received power packet, and a charging status packet from the wireless power receiver.

4. The power transmission method according to claim 1, wherein the reference peak frequency is pre-assigned to the wireless power receiver.

5. The power transmission method according to claim 1, wherein the response signal is determined by comparing a measured peak frequency of a power signal transmitted by the wireless power transmitter with a critical frequency, and the critical frequency is determined based on the reference peak frequency and the wireless power transmitter.

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