Method for detecting foreign substances and device 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 a wireless power transmission technology, and more particularly to a method for detecting foreign objects in a wireless charging system. 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 is emerging. This holds true.

[0003] In order for information and communication devices to be connected anytime and anywhere, sensors with built-in computer chips with communication functions must be installed in all facilities in society. Therefore, the power supply problem for these devices or sensors has become a new issue. In addition, as the number of types of portable devices such as Bluetooth handsets and music players such as iPods, as well as mobile phones, has rapidly increased, the task of charging the batteries has become time-consuming and troublesome for users. Wireless power transmission technology has recently been attracting attention as a way to solve this problem. Patent Document 1: Korean Patent Publication No. 10-2015-0143654 Patent Document 2: Korean Patent Publication No. 10-2016-0061121

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

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

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

[0007] The magnetic resonance method uses electric or magnetic fields instead of electromagnetic waves or currents. The magnetic resonance method is hardly affected by electromagnetic waves, so it is not affected by other electronic devices or the human body. On the other hand, it can only be used at a limited distance and in a limited space. However, it has the disadvantage that the energy transfer efficiency is somewhat low.

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

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

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

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

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

[0013] The present invention has been devised to solve the above-mentioned problems of the prior art, and the object of the present invention is to The present invention provides a method for detecting foreign matter in wireless charging, and an apparatus and system therefor. do.

[0014] Another object of the present invention is to provide a method for determining weights that are determined linearly or exponentially by the reference quality factor values. By determining the critical value or critical range for detecting foreign substances dynamically, An object of the present invention is to provide a wireless power transmission device that can reliably detect a foreign substance.

[0015] Another object of the present invention is to provide a method for determining the quality factor value of a resonant circuit and an inductor, the quality factor value being measured before the ping stage. It is an object of the present invention to provide a wireless power transmission device capable of detecting a foreign substance based on a power loss value. .

[0016] It is still another object of the present invention to provide a resonant circuit before the ping step if an object is detected in the charging area. Measure the inductance value as well as the quality factor value of the By comparing the measured value with the critical value determined based on the The present invention provides a method for detecting foreign substances and an apparatus and system for the same. Another object of the invention is to provide a method for determining a quality factor based on measured quality factor values ​​corresponding to specific frequencies within an operating frequency band. The present invention provides a wireless power transmitter capable of detecting a foreign substance.

[0017] Another object of the present invention is to provide a method for determining the average quality factor of a particular frequency in a frequency band of operation. The present invention provides a wireless power transmitter capable of detecting a foreign substance based on a power value.

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

[0019] The present invention can provide a method for detecting foreign substances and an apparatus and system therefor.

[0020] A wireless power transmitter having a resonant circuit for wirelessly transmitting power according to an embodiment of the present invention The method for detecting a foreign object in the charging area includes the steps of: detecting an object placed in the charging area; If so, measuring a quality factor value of the resonant circuit and transmitting a sensing signal to control wireless power. identifying a receiver and receiving a reference quality factor value from the identified wireless power receiver. determining a threshold value for detecting foreign matter based on the measured quality factor value and the previous and determining whether or not a foreign substance is present by comparing the determined critical value, A weighting factor that increases with the reference quality factor value may be applied to determine the quality factor.

[0021] Here, the weight value may increase linearly or exponentially according to the reference quality factor value. can.

[0022] In addition, the threshold value is determined by using configuration factors corresponding to the wireless power transmitter and a predefined A tolerance is further applied, and the critical value is the product of the reference quality factor value and the composition factor. can be determined by adding the tolerance to and subtracting the weighting value. .

[0023] Furthermore, the foreign substance detection method is such that, if the determination result indicates that a foreign substance is not present, the identified foreign substance is and if it is determined that a foreign object is present, A predefined alarm is issued to interrupt power transmission through the resonant circuit to indicate that a foreign object has been detected. and outputting a signal.

[0024] Also, if the power transmission is interrupted, detecting an object placed in the charging area. It is possible to regress.

[0025] The foreign substance detection method further comprises: The determined threshold is compared to determine whether the detected foreign matter has been removed from the charging area. A further step of verifying may be included.

[0026] Also, when the foreign matter is removed as a result of the check, the interrupted power transmission is resumed. It is possible.

[0027] In addition, the reference quality factor value is included in a foreign substance detection status packet received in the negotiation stage. can be received.

[0028] The step of determining whether or not the foreign matter exists may further comprise the step of determining whether or not the measured quality factor value is greater than or equal to the critical value. determining that no foreign matter is present if the measured quality factor value exceeds the clinical value; and determining that a foreign substance is present if the threshold value is not exceeded.

[0029] Wireless power transmission with a resonant circuit for wirelessly transmitting power according to another embodiment of the present invention The method for detecting a foreign object in a mobile phone includes the steps of: detecting an object placed in a charging area; If detected, a quality factor value of the resonant circuit is measured, and a detection signal is sent to wirelessly transmit the quality factor value. identifying a wireless power receiver; and receiving a reference quality factor from the identified wireless power receiver. determining a critical range for detecting foreign matter based on the measured quality factor value; and determining whether or not a foreign substance is present by comparing the determined critical range with the determined critical range, The boundary range is determined by applying the upper and lower weighting values ​​which increase according to 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 charger, a sensing unit for sensing an object placed in the charging area, and a sensor for detecting the object. When a body is detected, a measurement unit measures a quality factor value of the resonant circuit, and a wireless power The foreign substance detection status packet is received from the receiver, and a reference quality factor value is used to determine whether the foreign substance detection status packet is detected. and comparing the measured quality factor value with the determined critical value to determine a difference. a control unit for determining whether a substance is present, the critical value being increased by the reference quality factor value. The weighting factor to be applied can be determined.

[0031] Here, the weight increases linearly or exponentially according to the reference quality factor value, The threshold value is preset to a value obtained by multiplying the reference quality factor value by a configuration factor corresponding to the wireless power transmitter. The weighted value can be determined by adding a defined tolerance and 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 generated which interrupts the transmission of power through the circuit and indicates that a foreign object has been detected. The signal can be controlled to be output.

[0033] The control unit returns to the selection stage after the power transmission is interrupted to measure the resonant circuit. and comparing the quality factor value of the determined critical value to determine whether the detected foreign matter is in the charging area. You can check to see if it has been removed.

[0034] If the foreign matter is removed as a result of the check, the control unit The transmission can be controlled to resume.

[0035] The foreign matter detection device also converts DC power applied from a power source into a specific DC power. and an inverter that converts the converted DC power into AC power. and when the measurement by the measurement unit is completed, the control unit controls the wireless power receiver. The DC / DC converter and the front end are connected to each other so that a digital ping for identification is periodically sent. controlling the inverter when a signal strength indicator corresponding to the digital ping is received , the wireless power receiver can be identified.

[0036] The measurement unit detects the resonance capacitance based on a voltage measured across the resonance capacitor. The quality factor value of the circuit can be measured.

[0037] 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 charger, a sensing unit for sensing an object placed in the charging area, and a sensor for detecting the object. When a body is detected, a measurement unit measures a quality factor value of the resonant circuit, and a wireless power The foreign substance detection status packet is received from the receiver, and a reference quality factor value is used to determine whether the foreign substance detection status packet is detected. determining a critical range for the quality factor and comparing the measured quality factor value with the determined critical range. and a control unit for determining whether or not a foreign substance is present based on the reference quality factor value. The upper and lower limit weighting values ​​may be applied to determine the weighting factor.

[0038] A wireless power transmitter having a resonant circuit for wirelessly transmitting power according to an embodiment of the present invention The method for detecting a foreign object in the present invention includes the steps of: measuring a first inductance value of the resonant circuit; receiving a foreign substance detection status packet from a line power receiver; determining a threshold value for detecting a foreign substance based on the measured first inductance; and comparing the temperature difference with the determined critical value to determine whether or not a foreign substance is present. This can be done.

[0039] The method for detecting a foreign object includes the steps of: detecting an object placed in a charging area; and identifying a power receiver, wherein the measured first inductance value is This may include an inductance value of the resonant circuit that is changed by a sensed object.

[0040] In addition, the first inductance value is set to a value that causes the wireless power receiver to This can be measured before proceeding to the identification stage.

[0041] The method further includes identifying the wireless power receiver after the object is detected. The method may further include measuring a quality factor value of the co-advance circuit before proceeding to the step of do.

[0042] The foreign substance detection method further comprises: determining whether or not the foreign substance is present; The method may further include interrupting power transmission to the receiver.

[0043] The foreign substance detection method further comprises: The method may further include correcting the power transmitted to the wireless power receiver.

[0044] The method for detecting a foreign substance further comprises: detecting a foreign substance based on a result of the determination of the presence or absence of the foreign substance; The method may further include the step of outputting an alarm signal indicating that the detection has been performed.

[0045] The foreign object detection method further includes detecting an object placed in the charging area after the power transmission is interrupted. The step of sensing may further be included.

[0046] The foreign object detection method further includes, after the power transmission is interrupted, detecting a second inductor of the resonant circuit. measuring a second inductance value; and calculating the measured second inductance value and the determined critical value. and comparing to determine whether the detected foreign matter has been removed from the charging area. It can be included in the following:

[0047] The foreign substance detection status packet also includes at least a reference quality factor value and a reference inductance value. It may contain at least one.

[0048] In addition, the reference inductance value is set to the value obtained when the wireless power receiver is in the charging state without any foreign matter. The inductance value of the resonant circuit measured when the resonant circuit is located in a region of the electric field may be included. .

[0049] In one embodiment, the foreign substance detection status packet further includes a mode field. The reference inductance value is included in the foreign object detection status packet. The first mode may include a first mode of indicating.

[0050] In another embodiment, the foreign substance detection status packet further includes a mode field. The foreign substance detection status packet includes the reference inductance value and the reference A second mode may be included to indicate inclusion of a quasi-quality factor value.

[0051] The determined critical values ​​include a quality factor critical value and an inductance critical value, The quality factor critical value and the inductance critical value are the reference quality factor value and the reference inductance value. For each of the impedance values, a value smaller than the predetermined ratio can be included.

[0052] Also, the determined critical value is increased by a preset ratio with respect to the reference inductance value. The threshold value may be included.

[0053] The foreign substance detection method further includes receiving a signal for correcting the power from the wireless power receiver. The method further includes receiving a power intensity packet, the received power intensity packet being The wireless power receiver corresponding to the load or the wireless power receiver corresponding to the load connection state It may include the received power of the line power receiver.

[0054] The step of determining whether or not the foreign matter exists comprises the steps of: A first foreign substance determination step of determining whether or not a foreign substance is present by comparing the factor critical values; The first inductance value is compared with the critical inductance value to determine whether or not a foreign substance is present. and a second foreign matter determination step.

[0055] Also, at least one of the first foreign matter determining step and the second foreign matter determining step If it is determined at the judgment stage that foreign matter is present, it is ultimately determined that foreign matter is present. can be done.

[0056] According to another embodiment of the present invention, the foreign substance detection device includes a resonant capacitor and an inductor. A resonant circuit, a charging area disposed on the inductor, and a first inductor of the resonant circuit. The measurement unit measures the impedance value and the foreign object detection status packet received from the wireless power receiver. and determining a threshold value for detecting a foreign substance based on the first inductance value and the first inductance value. and a control unit for determining whether or not a foreign substance is present by comparing the determined critical value. .

[0057] The control unit is configured to sense an object located in the charging area, and the measurement The first inductance value is a change in the inductance of the resonant circuit caused by the sensed object. It may include a inductance value.

[0058] The measurement unit is configured to measure a quality factor value of the co-evolution circuit, The quality factor value thus determined includes a quality factor value of the resonant circuit that has been changed by the sensed object. It is possible.

[0059] Also, the inductance value of the co-moving circuit includes the inductance value of the inductor. It is possible.

[0060] Also, if the measured first inductance value is greater than the determined critical value, The control unit may correct the power transmitted to the wireless power receiver.

[0061] Also, the measured first inductance value is equal to or less than the determined critical value. If the difference is smaller, the control unit controls to interrupt the power transmission to the wireless power receiver. This can be done.

[0062] The foreign substance detection status packet also includes at least a reference quality factor value and a reference inductance value. It may contain at least one.

[0063] In one embodiment, the foreign substance detection status packet further includes a mode field. The reference inductance value is included in the foreign object detection status packet. The first mode may include a first mode of indicating.

[0064] In another embodiment, the foreign substance detection status packet further includes a mode field. The foreign substance detection status packet includes the reference inductance value and the reference A second mode may be included to indicate inclusion of a quasi-quality factor value.

[0065] The determined critical values ​​include a quality factor critical value and an inductance critical value, The quality factor critical value and the inductance critical value are the reference quality factor value and the reference inductance value. For each of the impedance values, a value smaller than the predetermined ratio can be included.

[0066] Also, the determined critical value is increased by a preset ratio with respect to the reference inductance value. The threshold value may be included.

[0067] The control unit compares the measured quality factor value with the quality factor critical value to determine whether or not a foreign object is present. A first foreign substance determination is performed to determine whether a foreign substance is present, and the measured inductance value and the inductance are compared. The second foreign matter judgment is performed by comparing the inductance critical value to judge whether or not foreign matter exists. can.

[0068] In addition, the first foreign substance judgment and the second foreign substance judgment are performed based on at least one of the judgments. If it is determined that a substance is present, the control unit finally determines that a foreign substance is present. can be done.

[0069] The foreign matter detection device also converts DC power applied from a power source into a specific DC power. and an inverter that converts the converted DC power into AC power. and when the measurement by the measurement unit is completed, the control unit controls the wireless power receiver. The DC / DC converter and the front end are connected to each other so that a digital ping for identification is periodically sent. controlling the inverter when a signal strength indicator corresponding to the digital ping is received , the wireless power receiver can be identified.

[0070] The measurement unit also measures the voltage, current and impedance across the resonant capacitor. The first inductance value can be determined based on at least one of the .

[0071] The measurement unit also measures the product based on a voltage measured across the resonant capacitor. a quality factor measuring unit for calculating a quality factor value; and an inductance measuring unit that calculates the inductance value based on the current. do.

[0072] According to an embodiment of the present invention, a method for detecting a foreign object in a wireless power transmitter includes: measuring a first quality factor value for the first frequency and measuring a second quality factor value for the second frequency. and determining whether or not a foreign substance is present on the charging area based on the first quality factor value and the second quality factor value. and determining a state of the device.

[0073] In one example, the second frequency is greater than the first frequency and the second quality factor value is If the quality factor is greater than the first quality factor value, it can be determined that a foreign substance is present in the charging area. do.

[0074] As another example, if the second quality factor value is greater than the first quality factor value, the charging region It can be determined that an unaligned wireless power receiver is present in the area.

[0075] The foreign substance detection method further comprises transmitting wireless power according to the determined presence state of the foreign substance. and the foreign matter presence / absence state is a foreign matter presence state and a foreign matter absence state. may include.

[0076] The foreign matter presence state is a state in which the second quality factor value is greater than the first quality factor value. It can include the form.

[0077] The foreign matter-free state is determined when the second quality factor value is equal to or greater than the first quality factor value. It may contain smaller states.

[0078] The foreign matter detection method further comprises: If so, the method may further include the step of outputting a predetermined alarm signal.

[0079] The method for detecting a foreign substance further comprises the steps of: detecting a presence of the foreign substance during power transmission; The method may further include temporarily suspending power transmission.

[0080] The method of detecting a foreign object may further include detecting the foreign object detected while the power transmission is temporarily stopped. The method further includes the step of determining whether the substance has been removed from the charging area, and When the foreign object is removed, the temporarily interrupted power transmission can be resumed.

[0081] The method of detecting a foreign substance further includes a step of entering a selection step after outputting the alarm signal. It may further include:

[0082] The foreign substance detection method further includes, after the alarm signal is output, before entering the selection step, The method further includes the step of determining whether the detected foreign matter has been removed from the charging area, If the foreign matter is removed, the selection step can be carried out.

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

[0084] According to another embodiment of the present invention, a method for detecting a foreign object in a wireless power transmitter includes: calculating a first quality factor average value corresponding to a predetermined upper limit frequency band within the operating frequency band; calculating a second quality factor average value corresponding to a predetermined lower limit frequency band within the frequency band; A charging control method for the wireless power transmitter based on the first quality factor average value and the second quality factor average value. and determining whether foreign matter is present in the region.

[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 a foreign substance is present in the charging area.

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

[0087] According to another embodiment of the present invention, a foreign substance detection device provided in a wireless power transmitter is measuring a first quality factor value for a first frequency within a set operating frequency band; a quality factor measurement unit for measuring a second quality factor value for a second frequency in a wavenumber band; Determining whether a foreign substance is present in the charging area based on the quality factor value and the second quality factor value. A detection unit may be included.

[0088] In one example, the second frequency is greater than the first frequency and the second quality factor value is If the quality factor value is greater than the first quality factor value, the detection unit determines that a foreign substance is present in the charging area. It is possible.

[0089] In another embodiment, the second frequency is greater than the first frequency and the second quality factor value is If the quality factor value is greater than the first quality factor value, the detection unit detects a wireless device that is not aligned with the charging area. It may also be determined that a power receiver is present.

[0090] Further, the foreign substance detection device detects the presence of a foreign substance in the charging area as a result of the determination. The device may further include an alarm unit that outputs a predetermined alarm signal if detected.

[0091] In addition, when the presence of the foreign substance is detected, the foreign substance detection device detects the presence of the foreign substance during power transmission. The power supply may further include a controller for temporarily suspending the power transmission.

[0092] The control unit detects whether the foreign matter is charged while the power transmission is temporarily stopped. If the detected foreign matter is removed from the electric field, In this case, the temporarily suspended power transmission can be resumed.

[0093] The control unit controls the device to enter a selection stage after outputting the alarm signal. It is possible.

[0094] Also, after the alarm signal is output and before the selection step is entered, the control unit It is then checked whether the foreign matter has been removed from the charging area. If the foreign matter has been removed, If so, control can be exercised to enter the selection step.

[0095] Also, the second frequency is greater than the first frequency, and the second quality factor value is greater than the first frequency. If the value obtained by subtracting the quality factor value exceeds a predetermined reference value, the detection unit detects an abnormality in the charging area. It can be determined that a substance is present.

[0096] According to another embodiment of the present invention, a foreign matter detection device provided in a wireless power transmitter includes a a quality factor measurement unit for measuring a quality factor value within an operating frequency band of Based on at least one of the quality factor values ​​measured corresponding to a predetermined upper frequency band, A first quality factor average value is calculated, which corresponds to a predetermined lower limit frequency band within the operating frequency band. Calculating a second quality factor average value based on at least one of the measured quality factor values. an average calculation unit for calculating the average of the first quality factor and the average of the second quality factor, and a detection unit for determining whether a foreign object is present in the charging area of ​​the power transmitter.

[0097] As an example, the detection unit detects whether the first quality factor average value is greater than the second quality factor average value. If the detection result is not significant, it can be determined that a foreign substance is present in the charging area.

[0098] As another example, the detection unit may calculate the second quality factor average value from the first quality factor average value. If the subtracted value exceeds a predetermined reference value, it is determined that a foreign substance is present in the charging area. It is also possible.

[0099] Further another embodiment of the present invention is a method for detecting foreign matter comprising the steps of: It is possible to provide a computer-readable recording medium having a program for performing the above-mentioned operations recorded thereon.

[0100] The above aspects of the present invention are merely some of the preferred embodiments of the present invention, and the technical features of the present invention may be varied in various ways. Various illustrated embodiments are described in detail below by those skilled in the art. These and other objects, features and advantages of the present invention will become apparent from the following detailed description of the invention. Effect of the Invention

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

[0102] The present invention provides a method for detecting foreign matter for wireless charging, and an apparatus and system therefor. There are advantages.

[0103] The present invention also relates to a method for detecting foreign substances that can detect foreign substances more accurately, and It would be an advantage to provide an apparatus and system for:

[0104] In addition, the present invention can minimize unnecessary power consumption and heat generation caused by foreign matter. There are advantages.

[0105] In addition, the present invention reflects weights determined linearly or exponentially by the reference quality factor values. By dynamically determining the critical value or critical range for detecting foreign substances, It would be advantageous to provide a wireless power transmission device capable of detecting foreign matter.

[0106] In addition, the present invention uses the quality factor value and inductance of the resonant circuit measured before the ping step. The present invention provides a wireless power transmission device capable of detecting a foreign substance based on the value.

[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 uses FOD status packets during negotiation By comparing the measured value with the determined critical value, foreign substances can be detected more accurately. It would be advantageous to provide a possible foreign material detection method and an apparatus and system therefor.

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

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

[0110] In addition, the present invention uses the average quality factor measured at a specific frequency within the operating frequency band. It would be advantageous to provide a wireless power transmitter capable of detecting foreign objects based on this.

[0111] In addition, the present invention not only has the advantage of minimizing foreign substance detection errors, It is expected that unnecessary power consumption and damage to equipment 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 clearly explain the present invention to those skilled in the art. Wax. [Brief description of the drawings]

[0113] [Figure 1] 1 is a block diagram illustrating a wireless charging system according to an embodiment of the present invention.

[0114] [Diagram 2] 4 is a state transition diagram illustrating a wireless power transmission process according to an embodiment of the present invention.

[0115] [Diagram 3] 1 is a block diagram illustrating the structure of a wireless power receiver that operates in conjunction with a wireless power transmitter.

[0116] [Figure 4] FIG. 2 is a diagram illustrating a packet format according to an embodiment of the present invention.

[0117] [Diagram 5] FIG. 2 is a diagram for explaining types of packets according to an embodiment of the present invention.

[0118] [Figure 6a] 1 is a block diagram illustrating a structure of a foreign substance detection device according to an embodiment of the present invention.

[0119] [Figure 6b] FIG. 11 is a block diagram illustrating a structure of a foreign substance detection device according to another embodiment of the present invention.

[0120] [Figure 7a] 10 is a diagram illustrating a message structure of a Foreign Object Detection Status Packet according to an embodiment of the present invention.

[0121] [Figure 7b] A diagram to explain the message structure of an FOD status packet according to one embodiment of the present invention.

[0122] [Figure 7c]A diagram for explaining the message structure of an FOD status packet according to another embodiment of the present invention.

[0123] [Figure 8a] 4 is a diagram illustrating a state transition process for detecting foreign matter in a foreign matter detection device according to an embodiment of the present invention.

[0124] [Figure 8b] 4 is a diagram illustrating a state transition process for detecting foreign matter in a foreign matter detection device according to an embodiment of the present invention.

[0125] [Figure 9a] 10 is a flowchart illustrating a method for detecting a foreign object in a wireless power transmission apparatus according to another embodiment of the present invention.

[0126] [Figure 9b] 10 is a flowchart illustrating a method for detecting a foreign object in a wireless power transmission apparatus according to another embodiment of the present invention.

[0127] [Figure 10] 11 is a graph showing an experimental result illustrating a degree of decrease in a perceived quality value with respect to a reference quality factor value for each receiver type when a foreign object is placed in a charging area according to an embodiment of the present invention. [Figure 11] 11 is a graph showing an experimental result illustrating a degree of decrease in a perceived quality value with respect to a reference quality factor value for each receiver type when a foreign object is placed in a charging area according to an embodiment of the present invention.

[0128] [Figure 12] The measurement results of the quality factor value and the inductance value depending on the presence or absence of foreign matter for each receiver type for the resonant circuit are shown.

[0129] [Figure 13a] 13 is a diagram illustrating a message structure of an FOD status packet according to yet another embodiment of the present invention.

[0130] [Figure 13b] 13 is a diagram illustrating a message structure of an FOD status packet according to yet another embodiment of the present invention.

[0131] [Figure 13c] 13 is a diagram illustrating a message structure of an FOD status packet according to yet another embodiment of the present invention.

[0132] [Figure 13d] A diagram to explain the message structure of an FOD status packet according to one embodiment of the present invention. [Figure 13e] A diagram to explain the message structure of an FOD status packet according to one embodiment of the present invention. [Figure 13f] A diagram to explain the message structure of an FOD status packet according to one embodiment of the present invention. [Figure 13g] A diagram to explain the message structure of an FOD status packet according to one embodiment of the present invention.

[0133] [Figure 14] 11 is a flowchart illustrating a method for detecting FOD according to another embodiment of the present invention.

[0134] [Figure 15] 11 is a flowchart illustrating a method for detecting FOD according to yet another embodiment of the present invention.

[0135] [Figure 16] 1 illustrates a quality factor table according to one embodiment of the present invention.

[0136] [Figure 17] 1 is a block diagram for explaining a configuration of an FO detection device according to an embodiment of the present invention.

[0137] [Figure 18] 11 is a flowchart illustrating a method for detecting FOD according to yet another embodiment of the present invention.

[0138] [Figure 19] 11 is a flowchart illustrating a method for detecting FOD according to yet another embodiment of the present invention.

[0139] [Figure 20] 1 is a flowchart illustrating a method for detecting an FO based on a quality factor value according to an embodiment of the present invention.

[0140] [Figure 21] FIG. 21 is a block diagram for explaining the structure of an FO detection device corresponding to the embodiment of FIG. 20.

[0141] [Figure 22] 11 is a flowchart illustrating a method for detecting an FO based on a quality factor value in another embodiment of the present invention.

[0142] [Diagram 23] FIG. 23 is a block diagram for explaining the structure of an FO detection device corresponding to the embodiment of FIG. 22.

[0143] [Figure 24a] 24 is a graph showing experimental results for explaining the logical basis of the embodiments of FIGS. 14 to 23. [Figure 24b] 24 is a graph showing experimental results for explaining the logical basis of the embodiments of FIGS. 14 to 23. [Figure 24c] 24 is a graph showing experimental results for explaining the logical basis of the embodiments of FIGS. 14 to 23. [Fig. 24d] 24 is a graph showing experimental results for explaining the logical basis of the embodiments of FIGS. 14 to 23. [Figure 24e] 24 is a graph showing experimental results for explaining the logical basis of the embodiments of FIGS. 14 to 23.

[0144] [Diagram 25]11 is a diagram illustrating the relationship between the quality factor value and the maximum quality factor peak frequency depending on the arrangement of a wireless power receiver and a foreign object in the charging area of ​​a wireless power transmitter.

[0145] [Figure 26] 4 is a diagram illustrating a state transition process for detecting foreign matter in a foreign matter detection device according to an embodiment of the present invention.

[0146] [Figure 27] A diagram for explaining the message structure of an FOD status packet according to another embodiment of the present invention.

[0147] [Figure 28] 4 is a diagram illustrating a state transition process for detecting foreign matter in a foreign matter detection device according to an embodiment of the present invention.

[0148] [Figure 29] 4 is a diagram illustrating a state transition process for detecting foreign matter in a foreign matter detection device according to an embodiment of the present invention.

[0149] [Diagram 30] 13 is a diagram illustrating a message structure of an FOD status packet according to yet another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0150] In one embodiment, a wireless power transmitter having a resonant circuit for wirelessly transmitting power is provided. The method for detecting a foreign object includes the steps of detecting an object placed in a charging area, and detecting the object when the object is detected. For example, the steps of measuring a quality factor value of the resonant circuit and transmitting a sensing signal to a wireless power receiver include: and determining based on a reference quality factor value received from the identified wireless power receiver. determining a critical value for detecting foreign matter based on the measured quality factor value; and determining whether or not a foreign substance is present by comparing the determined critical value with the reference critical value, A weighting factor that increases with the quality factor value may be applied to determine the quality factor. MODE FOR CARRYING OUT THEINVENTION

[0151] Hereinafter, the apparatus and various methods to which the embodiments of the present invention are applied will be described in detail with reference to the drawings. The suffixes "module" and "part" for components used in the following description are for clarity. These are given or mixed with consideration only to the ease of drafting details, and are not distinguished from each other as such. It does not have a different meaning or role.

[0152] In the description of the embodiment, when it is described as being formed "on or under" each component, In this case, the upper or lower means two components that are in direct contact with each other or are in contact with one or more further components. This includes all cases where the above-mentioned is formed between two components. In this case, it can include not only the meaning above but also the meaning below based on one component.

[0153] In the description of the embodiment, a device equipped with a function of transmitting wireless power in a wireless charging system For convenience of explanation, the device will be referred to as a wireless power transmitter, a wireless power transmission device, or a wireless power transmission device. , wireless power transmitter, transmitting end, transmitter, transmitting device, transmitting side, wireless power transmission device, wireless power In addition, the wireless power receiving device will receive wireless power from the wireless power transmitting device. For the sake of convenience, the following expressions are used to refer to a device equipped with the functions of wireless power receiving device, Wireless power receiver, wireless power receiving device, wireless power receiver, receiving terminal, receiving side, receiving device It can be used in combination with other devices, such as transmitters, receivers, etc.

[0154] The transmitter according to the present invention may be in the form of a pad, a stationary type, or an AP (Access Point) type. It can be configured in various forms, including as a stand, ceiling-embedded form, or wall-mounted form. A single transmitter can transmit power to multiple wireless power receiving devices. To this end, the transmitter may also comprise at least one means for wireless power transmission. The line power transmission means generates a magnetic field in a power transmitting end coil, and receives the power by the influence of the magnetic field. Based on the electromagnetic induction method, which uses the principle of electromagnetic induction to charge the battery by inducing electricity in the end coil. Various wireless power transmission standards can be used. Here, the wireless power transmission means is a wireless The charging technology standard organization WPC (Wireless Power Consortium) ) and the Electromagnetic Induction defined by the Power Matters Alliance (PMA) It may include conductive wireless charging technology.

[0155] Also, a receiver according to an embodiment of the present invention includes at least one wireless power receiving means. It is also possible to receive radio power from two or more transmitters simultaneously. The line power receiving means is the WPC (Wireless Power Charging Standards Committee) Consortium and PMA (Power Matters Alliance) ) can include electromagnetic induction wireless charging technology as defined in

[0156] The receiver according to the present invention can be used in a mobile phone, a smartphone, smart phone, laptop computer , digital broadcasting terminals, PDAs (Personal Digital Assistants) nts), PMP (Portable Multimedia Player), navigation game applications, MP3 players, electric toothbrushes, electronic tags, lighting devices, remote controls Used for small electronic devices such as sensors, floats, and wearable devices like smart watches. However, the present invention is not limited to this, and the wireless power receiving means according to the present invention may be installed. Any device that can charge a battery will suffice.

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

[0158] Referring to FIG. 1, a wireless charging system mainly includes a wireless power transmitting terminal that transmits power wirelessly. 10, a wireless power receiving terminal 20 for receiving the transmitted power, and The electronic device 30 may include:

[0159] As an example, the wireless power transmitting end 10 and the wireless power receiving end 20 are used for wireless power transmission. It performs in-band communication, exchanging information using the same frequency band as the It is possible.

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

[0161] As another example, the wireless power transmitting end 10 and the wireless power receiving end 20 may be used as a dynamic power transmitting end. Out-of-band (OOB) is a type of communication that exchanges information using a separate frequency band different from the operating frequency. d) Communications may also be carried out.

[0162] For example, information exchanged between the wireless power transmitting end 10 and the wireless power receiving end 20 may be In addition to status information, control information may also be included. The state information and control information will become more apparent from the description of the embodiments below.

[0163] The in-band and out-of-band communications may provide bidirectional communication, but are not limited thereto. However, in other embodiments, one-way or half-duplex communication may be provided. do.

[0164] For example, in unidirectional communication, the wireless power receiving end 20 transmits information only to the wireless power transmitting end 10. However, the present invention is not limited to this. It may also transmit information to a

[0165] The half-duplex communication method allows bidirectional communication between the wireless power receiving end 20 and the wireless power transmitting end 10. However, it has the characteristic that information can be transmitted by only one device at any one time.

[0166] According to an embodiment of the present invention, the wireless power receiving end 20 acquires various status information of the electronic device 30. As an example, the status information of the electronic device 30 may include current power usage information, execution information, and the like. Information to identify the application in use, CPU usage information, battery charge status information, battery -output voltage / current information, etc. from electronic device 30 Any information that can be obtained and that can be used for wireless power control is sufficient.

[0167] In particular, the wireless power transmitter 10 according to an embodiment of the present invention may include a predetermined The wireless power receiving end 20 can transmit the packet to the wireless power receiving end 20. If it is confirmed that the wireless power transmitter 10 supports the fast charging mode, The electronic device 30 can inform the user of this. The electronic device 30 has a predetermined display means, A display means, which may be a liquid crystal display, indicates that fast charging is possible. It is possible.

[0168] In addition, the user of the electronic device 30 presses a predetermined high-speed charging request button displayed on the liquid crystal display means. Alternatively, the wireless power transmitter 10 may be selectively controlled to operate in a fast charging mode. In this case, when the user selects the fast charging request button, the electronic device 30 performs a predetermined The high-speed charging request signal may be transmitted to the wireless power receiving end 20. The wireless power transmitting end generates a charging mode packet corresponding to the received fast charging request signal. 10, it can convert the general low-power charging mode into the fast charging mode. can.

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

[0170] Referring to FIG. 2, the power transfer from the transmitter to the receiver is largely divided into a selection stage. tion Phase 210, Ping Phase 220, Identification and Identification and Configuration Phase ase) 230, Negotiation Phase (Negotiation Phase) 240, Correction Phase ( Calibration Phase) 250, Power Trans fer Phase 260 and Renegotiation Phase )270 can be divided into:

[0171] A selection step 210 is performed to determine whether a particular error or fault occurs while initiating a power transfer or maintaining a power transfer. may be a transition state when a specific event is detected. The specific events will become apparent from the following description. Also, in the selection step 210, The transmitter can monitor the presence of an object on the interface surface. Then, if the transmitter detects that an object has been placed on the interface surface, a ping step 22 is performed. In the selection step 210, the transmitter selects a very short pulse of analog The transmitter coil or the primary coil (Primary coil) transmits an Analog Ping signal. Based on the current change in the ry coil, the active area on the interface surface is identified. It can detect the presence of objects in the surrounding area.

[0172] In the ping step 220, if the transmitter detects an object, it activates the receiver. Digital ping to identify receivers that are compatible with PC standards In the ping step 220, the transmitter transmits a response system to the digital ping. If no signal, e.g., a signal strength packet, can be received from the receiver, the selection stage is restarted. In the ping phase 220, the transmitter may transmit a ping from the receiver. When the power transmission is completed, i.e., when the charging completion packet is received, the selected A transition to step 210 may also be made.

[0173] Once the ping step 220 is complete, the transmitter identifies the receiver and transmits the receiver configuration and status information. A transition may then occur to an identification and configuration step 230 for collection.

[0174] In the identification and configuration step 230, the sender detects whether an unwanted packet is received (unex received packet), which is the time when a desired packet is not received within a predefined period of time. There is a time out, or a packet transmission error. n error), if the power transfer contract is not set (no power transfer contract fer contract) selection step 210.

[0175] The transmitter identifies the configuration packet received in the identification and configuration step 230. ion packet) Negotiation Field value Based on this, it can be determined whether or not entering the negotiation stage 240 is necessary.

[0176] If negotiation is necessary, the transmitter proceeds to a negotiation stage 240 to determine whether a desired FOD detection is required. The process can be carried out.

[0177] On the other hand, if the confirmation result indicates that negotiation is not necessary, the transmitter immediately proceeds to the power transmission step 260. It is also possible.

[0178] In the negotiation stage 240, the transmitter negotiates with the Foreign Observer (FOD) that includes the reference quality factor value. Inject Detection status packets can be received. The device can determine a threshold value for FO detection based on the reference quality factor value. The transmitter then calculates the density of the foreign matter by using a predetermined critical generating function with the reference quality factor value as a parameter. A critical value or critical range for determining the presence or absence of a substance can be determined. The critical value or critical range calculated by the function is a value smaller than the reference quality factor value. The threshold value (FO_Threshold) for detecting foreign matter according to the embodiment is the reference quality factor value. (RQF_Value), a configuration factor (De sign_factor), tolerance and weighting defined in the standard Here, the weighting value can be determined linearly depending on the reference quality factor value. Or it can increase exponentially. That is, the critical value for detecting foreign matter can be expressed by the following formula: 1:

[0179] FO_Threshold=(RQF_Value*Design_factor)+ tolerance-weight (Formula 1)

[0180] can be determined by:

[0181] In general, if a foreign object is placed in the charging area, the quality factor value measured in the resonant circuit of the transmitter In fact, in a wireless charging system, the charge area is charged by a foreign substance. When a substance is placed, the ratio of the measured quality factor value to the reference quality factor value is The type of receiver placed in the charging area, i.e., the reference quality factor value of the corresponding wireless power receiver In particular, the larger the standard quality factor value, the greater the reduction ratio of the quality factor value due to the placement of foreign substances. Therefore, the transmitter according to the present invention has a feature that the reference quality factor value is large. In the case of a wireless power receiver, the ratio of the critical value for detecting a foreign object to the reference quality factor value The critical value (or critical range) can be determined so that the However, the probability of failing to detect a foreign substance can be reduced.

[0182] The transmitter compares the quality factor value measured after object detection with the critical value determined for FO detection. By comparing the FO, it can determine whether there is an FO in the charging area, and the power supply can be determined based on the FO detection result. For example, if FO is detected, the transmitter can control the power transmission. and outputs a predefined warning alarm to indicate that an FO has been detected. It is possible.

[0183] If FO is detected, the transmitter can return to the selection step 210. If not detected, the transmitter proceeds through a correction stage 250 to a power transfer stage 260. In particular, if no FO is detected, the transmitter may adjust the receiving end in a correction step 250. The strength of the power received by the receiving end is determined, and the strength of the power transmitted from the transmitting end is determined. The power loss at the input and output ends can be measured. The power loss can be predicted based on the difference between the transmission power at the transmitting end and the reception power at the receiving end. According to one embodiment, the transmitter may calculate a critical frequency for FOD detection based on a predicted power loss. The value can also be corrected.

[0184] During the power transmission step 260, the transmitter detects whether an unwanted packet is received or not. ted packet), when a desired packet is not received for a predefined period of time. (time out), or a violation of an already established power transfer contract occurs (p ower transfer contract violation) Charging is complete If so, a transition can be made to selection step 210 .

[0185] In addition, in the power transmission step 260, the transmitter changes the power transmission contract depending on the state change of the transmitter. If the contract needs to be restructured, a transition to a renegotiation phase 270 may occur. If the renegotiation is successfully completed, the transmitter may revert to the power transfer stage 260 .

[0186] The power transfer agreement described above is set based on the status and characteristic information of the transmitter and receiver. As an example, the transmitter status information can include information about the maximum amount of power that can be transmitted, The receiver status information may include information about the number of receivers that can be accommodated, and the like. It may include information about power, etc.

[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 direct current / DC / DC Converter 330, Load 340, Sensing Unit 3 50, a communication unit 360, and a main control unit 370. 0 may 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 transmitter via in-band communication. 600, this is only one example. According to another embodiment of the present invention, the communication unit 360 is a frequency band used for wireless power signal transmission. It may also provide short-range two-way communication over a different frequency band.

[0190] The AC power received via the receiving coil 310 can be transmitted to the rectifier 320. The rectifier 320 converts the AC power into DC power and transmits it to the DC / DC converter 330. The DC / DC converter 330 adjusts the strength of the rectifier output DC power depending on the load 340. After being converted to a particular required intensity, it can be transmitted to the load 340 .

[0191] The sensing unit 350 measures the DC power intensity output from the rectifier 320 and transmits it to the main control unit 37. In addition, the sensing unit 350 can provide a receiving control signal by wireless power reception. The intensity of the current applied to the coil 310 is measured, and the measurement result is transmitted to the main control unit 370. The sensing unit 350 can also measure the internal temperature of the wireless power receiver 300. The determined temperature value may also be provided to the main controller 370.

[0192] As an example, the main control unit 370 may compare the measured rectifier output DC power intensity with a predetermined reference value. By comparing the voltages, it is possible to determine whether an overvoltage has occurred. A predetermined packet notifying that a voltage has been generated is generated and transmitted to the modulation unit 362. Here, the signal modulated by the modulation unit 362 is input to the receiving coil 310 or a separate The power may be transmitted to the wireless power transmitter 600 via a control signal (not shown). The control unit 370 detects that a detection signal is received when the rectifier output DC power intensity is equal to or greater than a predetermined reference value. When a sensing signal is received, the signal strength indicator corresponding to the sensing signal is The power signal is transmitted to the wireless power transmitter 600 via the modulation unit 362. As another example, the demodulation unit 361 may demodulate the AC current between the receiving coil 310 and the rectifier 320. The input signal or the output DC power signal of the rectifier 320 is demodulated to determine whether the sensing signal is received or not. The identification result can be provided to the main controller 370. At this time, the main controller 370 receives the sensing signal. The signal strength indicator corresponding to the signal is transmitted through the modulation unit 362. It is possible.

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

[0194] Referring to FIG. 4, a wireless power transmitter 10 and a wireless power receiver 20 are used for information exchange. The packet format 400 is used for obtaining synchronization for demodulating the corresponding packet and Preamble 410 field to identify the exact start bit of Header to identify the type of message included in the packet ) 420 field, which transmits the contents (or payload) of the corresponding packet The Message 430 field and the corresponding packet have an error. Contains a checksum 440 field to verify that the It can be done.

[0195] The packet receiving end determines the message 4 included in the packet based on the header 420 value. It can also distinguish between 30 sizes.

[0196] In addition, the header 420 can be defined for each step of the wireless power transmission process. The header 420 value is defined to have the same value at different stages of the wireless power transmission process. For example, referring to FIG. 10, the power transmission end (End Power Transfer) and the header value corresponding to the end of power transfer in the power transfer phase Note that both are 0x02 and are identical.

[0197] The message 430 includes data to be transmitted from the transmitting end of the corresponding packet. The data contained in the message 430 field is the report to the other party. rt), a request or a response, This is not limited to the above.

[0198] According to another embodiment of the present invention, a packet 400 may include a packet ID identifying a transmitting end that transmits the corresponding packet. receiving end identification information for identifying a receiving end that receives the corresponding packet; Here, the transmitting end identification information and the receiving end identification information may be included. The identification information may include IP address information, MAC address information, product identification information, etc. However, the present invention is not limited to the above. It is sufficient if the information is sufficient.

[0199] According to yet another embodiment of the present invention, a packet 400 is sent by multiple devices. If the relevant receiving group needs to receive the It may also include other information.

[0200] FIG. 5 illustrates a power transmission path in a wireless power receiver according to an embodiment of the present invention. FIG. 13 is a diagram for explaining types of sockets.

[0201] Referring to FIG. 5, a packet transmitted from a wireless power receiver to a wireless power transmitter is sensed as follows: Signal Strength (SSI) is used to transmit the strength information of the received ping signal. ) packet, power transmission type (End) for requesting the transmitter to stop power transmission After receiving the control error packet for control, the actual power transfer is Power Control Hold (PCH) for transmitting time information to wait before adjusting the power Receiver Hold-off packet, configuration packet for transmitting receiver configuration information Identification packet and extended identification packet for transmitting receiver identification information, general request message A general request packet for transmitting a message, a special request packet for transmitting a special request message, a FOD request packet for transmitting a reference quality factor value for FOD detection; A control error packet for controlling the transmitter's transmission power, and a renegotiation packet for starting renegotiation 24-bit received power packet and 8-bit received power packet for transmitting received power strength information The power packet includes a charging status packet for transmitting charging status information of the current load. This can be done.

[0202] The packet transmitted from the wireless power receiver to the wireless power transmitter is used for wireless power transmission. The signal may be transmitted using in-band communication using the same frequency band as that used by the signal.

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

[0204] Referring to FIG. 6a, the foreign substance detection device 600 includes a power supply unit 601, a DC / DC converter (D C-DC Converter) 610, Inverter (Inverter) 620, common The device includes a vibration circuit 630, a measurement unit 640, a communication unit 660, a sensing unit 670, and a control unit 680. The foreign matter detection device 600 according to the present embodiment is attached to a wireless power transmission device. It can be done.

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

[0206] The power supply unit 601 receives DC power via an external power supply terminal and converts it into a DC / DC converter 61. It can be transmitted to 0.

[0207] The DC / DC converter 610 receives the input from the power supply unit 601 under the control of the control unit 680. The strength of the DC power can be converted to a specific strength of DC power. The converter 610 may be a variable voltage converter capable of adjusting the voltage strength, but is not limited thereto. Not done.

[0208] The inverter 620 can convert the converted DC power into AC power. The inverter 620 converts the input DC power signal into AC power by controlling a number of switches provided therein. It can be converted into an electric power signal and output.

[0209] As an example, the inverter 620 includes a full bridge circuit. It can be, but is not limited to, a half bridge. e).

[0210] As another example, the inverter 620 may be used in both a half-bridge circuit and a full-bridge circuit. In this case, the control unit 680 controls the inverter 620 to be a half-blocking inverter. It can dynamically determine and control whether the converter operates as a full-bridge or a bridge. This can be done.

[0211] According to an embodiment of the present invention, a wireless power transmitting apparatus transmits power required by a wireless power receiving apparatus. The bridge mode of the inverter 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] For example, when the wireless power receiving device requires a low power of 5 W, the control unit 680 The inverter 620 can be controlled to operate in half-bridge mode. If the line power receiving device requires 15W of power, the control unit 680 operates in full-bridge mode. The control can be performed to operate the device.

[0213] As another example, the wireless power transmitter may be configured to adaptively switch to a bridge mode according to a sensed temperature. and drive the inverter 620 in the determined bridge mode. As an example, a wireless power transmission device that transmits wireless power in half-bridge mode can be used. If the temperature of the device exceeds a predetermined reference value, the control unit 680 deactivates the half-bridge mode. The full-bridge mode can be activated by controlling the The power transmitter uses a full bridge circuit to boost the voltage for the same power transmission. By reducing the intensity of the current flowing through the resonant circuit 630, The part temperature can be controlled so as to be maintained at or below a predetermined reference value.

[0214] In general, the amount of heat generated by electronic components installed in electronic devices depends on the amount of heat applied to the electronic components. It may be more sensitive to the magnitude of the current than to the magnitude of the voltage.

[0215] In addition, the inverter 620 can not only convert DC power to AC power, The strength of the AC power can also be varied.

[0216] As an example, the inverter 620 is used to generate AC power under the control of the control unit 680. Reference Alternating Current You can also adjust the frequency of the AC signal to adjust the strength of the AC power output. For this purpose, the inverter 620 is a frequency converter that generates a reference AC signal having a specific frequency. In another embodiment, the frequency generator may include a frequency oscillator. The oscillator is constructed separately from the inverter 620 and is mounted on one side of the foreign matter detection device 600. It is possible.

[0217] As another example, the foreign matter detection device 600 may be configured to control a switch provided in the inverter 620. The gate driver (not shown) for controlling the In this case, the gate driver receives at least one pulse from the control unit 680. The inverter can receive a pulse width modulated signal according to the received pulse width modulated signal. The control unit 680 can control the duty of the pulse width modulation signal. Duty Cycle, or Duty Rate te) and phase (Phase) to control the intensity of the output power of the inverter 620. The control unit 680 may receive a feedback signal from the wireless power receiving device. Adaptively controlling duty cycle and phase of pulse width modulated signal based on signal - Patents.com can be done.

[0218] The measurement unit 640 measures the voltage across the resonant capacitor 631 in response to a control signal from the control unit 680. Measure at least one of the pressure, current, and impedance to determine a quality factor for the resonant circuit 630. The quality factor and / or the inductance value can be calculated. The value and / or the inductance value is transmitted to the control unit 680, and the control unit 680 stores the The quality factor value and / or the inductance value transmitted from the measuring unit 640 are temporarily stored in the For example, the control unit 680 may select the charging area when an object is detected on the charging area during the selection step. For example, the measurement unit 640 may measure the quality factor value and / or the inductance value before entering the ping stage. It is possible to control the calculation.

[0219] If the control unit 680 receives an FOD status packet from the modulation unit 662 during the negotiation phase, the control unit 680 The threshold value ( or critical range) can be determined.

[0220] According to one embodiment, the threshold value (FO_Threshold) for detecting foreign matter is a reference quality factor. A child value (RQF_Value), a configuration factor ( Design_factor), tolerance defined in the standard, and The weighting factor may be determined based on the reference quality factor value. That is, the control unit 680 may increase the count in a linear or exponential manner as shown in Equation 1 below:

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

[0222] The threshold value for detecting foreign matter can be determined by the above.

[0223] As an example, the weighting value is calculated by a predetermined linear function using the reference quality factor value as a parameter. It can be calculated by, but is not limited to, a higher-order function of second degree or higher. It is also possible.

[0224] As another example, the weighting value may be predefined for each type of wireless power receiver. 0, for example, in a non-volatile memory. The weighting values ​​for each type of wireless power receiver may be maintained in the form of a mapping table. But not limited to this.

[0225] According to another embodiment, the threshold range for detecting foreign matter is the upper threshold (FO_Threshold _Upper_Limit) and the lower limit (FO_Theshold_Lower_Limit) mit), the reference quality factor value (RQF_Value), and the corresponding wireless power transmission The design factor (Design_factor) is preset according to the machine, and the standard The tolerance, upper weighting and lower weighting are determined based on the Here, the upper and lower limit weighting values ​​can be linearly or exponentially determined according to the reference quality factor value. That is, the control unit 680 calculates the following Equation 2:

[0226] FO_Threshold_Upper_Limit=(RQF_Value*Des ign_factor)+tolerance-upper weighted value

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

[0228] The control unit 680 determines the critical range for detecting foreign matter by the measurement. If the quality factor value is between the upper and lower critical limits, it is determined that foreign matter is present. It is possible.

[0229] According to another embodiment of the present invention, the threshold value (FO_Threshold) for detecting foreign matter is As shown in Table 1 below, the ratio is different depending on the magnitude of the reference quality factor (RQF). can also be applied to determine the

[0230] As an example, referring to Table 1 below, if the Reference Quality Factor (RQF) value is greater than 80, The difference ratio was set to 40%, and the detection of foreign substances was performed using the following method. The critical value (FO_Threshold) is RQFx0.66 + tolerance nce) can be calculated as follows:

[0231] As another example, referring to Table 1 below, Reference Quality Factor (RQF) values ​​greater than 50 If the difference is less than 60, the Diff Ratio is applied as 10%. The threshold value (FO_Threshold) for detecting foreign matter is RQF x 0.69 + tolerance. It can be calculated with a tolerance.

[0232] [Table 1]

[0233] The wireless power transmitter receives a reference quality factor value via a FOD status packet during a negotiation phase; The FO_Threshold may be adaptively determined according to the received reference quality factor value. The larger the RQF value shown in Table 1, the greater the gap between the RQF value and FO_Threshold. The difference value of increases according to the difference ratio corresponding to the corresponding RQF value. On the other hand, if the RQF value is small, The difference between the RQF value and FO_Threshold is the difference between the RQF value and the FO_Threshold. The above Table 1 is merely an example, and the difference ratio according to the RQF value is may be determined differently depending on the design and device configuration of a person skilled in the art. You have to be careful.

[0234] In general, if a foreign object is placed in the charging area, the quality factor value measured in the resonant circuit of the transmitter In fact, in a wireless charging system, the charge area is charged by a foreign substance. When a substance is placed, the ratio of the measured quality factor value to the reference quality factor value is The type of receiver placed in the charging area, i.e., the reference quality factor value of the corresponding wireless power receiver Therefore it is different.

[0235] In particular, the larger the reference quality factor value, the more rapidly the reduction rate of the quality factor value due to the placement of foreign substances increases. Therefore, the control unit 680 according to the present invention is characterized in that the reference quality factor value is large. In the case of a power receiver, the ratio of the critical value for detecting a foreign object to the reference quality factor value is A critical value (or critical range) can be determined so that the transmitter The probability of failing to detect a foreign substance can be reduced.

[0236] The control unit 680 receives the quality factor value measured after the object detection and the clinical condition determined for the FO detection. By comparing the threshold values, it can be determined whether FO exists in the charging area, and the FO detection result This allows the power transfer to be controlled.

[0237] As an example, if FO is detected, the control unit 680 can interrupt power transmission. It can be controlled to output a predetermined warning alarm to indicate that an FO has been detected. Here, the warning alarm is a beeper or an LED lamp provided in the foreign substance detection device 600. The output may be via at least one of a microphone, a vibrating element, and a liquid crystal display. , but is not limited to this.

[0238] For example, the control unit 680 may measure the object before entering the ping step after detecting the object in the selection step. If the quality factor value is less than the determined critical value, it is determined that a foreign substance is present in the charging area. It can be said that.

[0239] As another example, the control unit 680 may detect an object in the selection step and then measure the object before entering the ping step. If the determined quality factor value is within the determined critical range, foreign matter is present in the charging area. It can also be determined that:

[0240] The reference quality factor value included in the FOD status packet is the null value specified for standard performance testing. Quality factors calculated for the corresponding wireless power receiver at a specific position of the charging bed of the line power transmitter The minimum of the child values ​​can be determined.

[0241] Also, if a foreign object is detected during the negotiation stage, the control unit 680 returns to the selection stage and The measurement unit 640 can be controlled to calculate the quality factor value of the resonant circuit 630 at regular intervals. do.

[0242] At this time, the control unit 680 has already determined the quality factor value obtained when the foreign matter is detected. The detected foreign matter is removed from the charging area by comparing it with the determined critical value (or critical range). It is possible to determine whether

[0243] For example, the control unit 680 may determine that the quality factor value measured in the state where the foreign substance is detected has already been If the difference is greater than the determined critical value, it can be determined that the foreign matter has been removed. Then, the control unit 680 detects whether the quality factor value measured in the state where the foreign matter is detected is equal to or lower than the upper limit critical value. If the measured value exceeds this value, it can be determined that the foreign matter has been removed.

[0244] Also, the control unit 680 determines whether the threshold value is determined based on the above-mentioned Table 1 (hereinafter, for convenience of explanation, the threshold value determination table). The threshold value for detecting foreign matter can be adaptively determined by referring to the threshold value (called the "threshold rule").

[0245] The above-mentioned Table 1 is stored in a predetermined recording area of ​​a memory (not shown) provided in the foreign substance detection device 680. The control unit 680 may maintain the FOD including the reference quality factor value in the negotiation stage. When a status packet is received, the received reference quality factor value and the threshold value determination table are referenced. Then, a critical value for detecting foreign matter is determined, and the determined critical value is compared with the already measured quality factor value. It is possible to determine whether or not a foreign substance is present by comparing the measured value with the measured value.

[0246] Here, the threshold value determination table may be updated. can be connected to a specific server via a wired or wireless network, and the The critical value determination table can be updated in conjunction with the bar. The device can also receive and update the threshold value determination table from a connected wireless power receiver. can.

[0247] The threshold value determination table can be generated for each type of wireless power receiver, and the foreign object detection The device refers to a threshold value determination table corresponding to the identified type of wireless power receiver to determine whether or not a foreign object is present. A threshold value for quality detection may also be determined.

[0248] According to an embodiment, a wireless power receiver maintains a threshold value determination table for each type of wireless power transmitter. In this case, the wireless power receiver can detect the type of the wireless power transmitter that is identified. The corresponding threshold value determination table can also be transmitted to the corresponding wireless power transmitter. The receiver determines a threshold value for detecting a foreign substance based on the received threshold value determination table. It is also possible.

[0249] As described above, the foreign matter detection device according to the embodiment of the present invention includes a wireless power receiver. Refer to the critical value determination table corresponding to the type or (and) type of wireless power transmitter to determine the appropriate value. It is possible to adaptively determine a threshold value for detecting foreign matter.

[0250] If the foreign matter is removed, the control unit 680 re-enters the power transmission step. The charging of the wireless power receiving device can be controlled to be resumed.

[0251] The critical values ​​may also include an inductance critical value and a quality factor critical value. If the value is in a critical range, the critical range includes the inductance critical range and the quality factor critical range. The two thresholds can be used together to detect foreign objects. The device determines the threshold value corresponding to the type of reference value transmitted by the device, and detects foreign substances. It is possible.

[0252] Here, the FOD status packet includes a reference quality factor value or ( The control unit 680 may receive the reference inductance value. A quality factor for determining the presence or absence of foreign matter based on the quality factor value and the reference inductance value Critical values ​​and / or inductance critical values ​​can be determined. The value that is 90% of the factor value and the reference inductance value is the quality factor critical value and / or the inductance The ratio can be determined as a critical value of the temperature, but is not limited thereto, and can be determined by those skilled in the art. It can be defined differently depending on the instrument.

[0253] In one example, the control unit 680 may use a quality factor value (measured before the ping phase) that has already been stored. If the inductance is smaller than the determined quality factor critical value or if the inductance value already stored is If the inductance is smaller than the specified critical value, it can be determined that a foreign substance is present. do.

[0254] When it is determined that a foreign substance is present, the control unit 680 stops the power transmission and detects whether the foreign substance is detected. The device can be controlled to output a predetermined warning alarm indicating that a malfunction has been detected. For example, notification methods include beepers, LED lamps, vibration elements, and LCD displays. It can include, but is not limited to:

[0255] The reference quality factor value included in the FOD status packet is the charging status of the specified wireless power transmitter. The minimum value of the quality factor values ​​calculated for the corresponding wireless power receiver at a specific position of the node is determined. It can be done.

[0256] The inductance value included in the FOD status packet was specified for standard performance testing. The calculated inference corresponding to the wireless power receiver at a specific position of the wireless power transmitter charging bed A minimum of the inductance values ​​can be determined.

[0257] Also, if a foreign object is detected during the negotiation stage, the control unit 680 returns to the selection stage and A measurement unit 640 for calculating the quality factor value and the inductance value of the resonant circuit 630 at each period. In this case, the control unit 680 may control the amount of the foreign matter that is detected. The quality factor value and inductance value determined are respectively the critical value and the inductance value of the quality factor already determined. Compare with the inductance threshold to determine whether a previously detected foreign object has been removed from the charging area. As an additional embodiment, when the foreign matter is removed, the control unit 6 80 controls the wireless power receiving device to enter a power transmission step and resume charging. In this case, the identification and configuration stage and / or the negotiation stage can be skipped and the power transmission stage can be performed. can enter.

[0258] The demodulation unit 661 demodulates the in-band signal received from the wireless power receiving device and outputs the demodulated signal to the control unit 680. As an example, the demodulation unit 661 demodulates and controls the packet described above with reference to FIG. The information can be transmitted to the control unit 680.

[0259] The sensing unit 670 senses a specific terminal of the foreign substance detection device 600 (or the wireless power transmission device), Measures voltage, current, power, impedance, temperature, etc. at specific elements or specific positions It is possible.

[0260] For example, the sensing unit 670 measures the voltage / current of the DC converted power and controls it. The sensing unit 670 can provide the control unit 680 with information on whether overheating has occurred. and providing the measurement result to the control unit 680. In this case, the control unit 680 may also detect the voltage / current measured by the sensing unit 670. The power supply from the power source is adaptively cut off based on the value, or the power supply to the resonant circuit 630 is For this purpose, one side of the foreign matter detection device 600 is connected to a power source. The power supply from the unit 601 is cut off, or the DC power supplied to the inverter 620 is The power supply may further include a predetermined power interruption circuit for interrupting the power supply.

[0261] The sensing unit 670 may further include a Hall sensor, a pressure sensor, etc. In this case, the presence of an object in the charging area is detected by a hall sensor or pressure sensor. It can be, but is not limited to,

[0262] The sensing unit 670 detects a resonant circuit while transmitting an analog ping signal in the selection step. 630 detects changes in current, voltage, impedance, etc. to detect the presence of an object in the charging area. It can also sense whether

[0263] As described above, the foreign substance detection device 600 according to the present invention detects an object in the selection step. If so, the quality factor value of the resonant circuit is measured (or calculated) before entering the ping stage, and the negotiation stage is started. The presence of foreign matter is detected by comparing the measured quality factor value with the critical value (or critical range) determined at each stage. By determining the presence or absence of foreign matter, the probability of failing to detect the foreign matter can be significantly reduced. There is a point.

[0264] The sensing unit may be replaced with the measurement unit and omitted.

[0265] In addition, the foreign matter detection device 600 according to the present invention has a threshold value (or a critical range) for detecting foreign matter. By dynamically determining the range of the quality factor according to the reference quality factor value corresponding to the wireless power receiver. Thus, foreign object detection optimized for the corresponding wireless power receiver can be performed.

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

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

[0268] Referring to FIG. 7a, the FOD status packet message 700 has a length of 2 bytes. Reserved 701 field, 6 bits long, 2 bits long The Mode 702 field and the 1-byte length reference quality factor value ence Quality Factor Value) 703 fields Here, all bits in the reserved 701 field are recorded as 0.

[0269] As shown by reference numeral 704, the mode 702 field is set to binary '00'. For example, the reference quality factor value 703 field is set to a value indicating a state in which the power supply of the wireless power receiver is turned off. This may mean that the reference quality factor value determined by measuring the quality factor at the measurement point is recorded.

[0270] FIG. 7b is a block diagram illustrating a message structure of an FOD status packet according to an embodiment of the present invention. This is a diagram of.

[0271] Referring to FIG. 7b, the FOD status packet message 700 has a length of 2 bytes. The first data 701 field is 6 bits long, and the mode (Mo The reference quality factor (QQ702) field and the 1-byte long reference quality factor (QQ The information may include a Quality Factor Value (QFAV) 703 field.

[0272] As shown by reference numeral 704, the mode 702 field is set to binary '00'. For example, the total bits of the first data 701 field are recorded as 0, and the reference quality factor value 703 field is recorded as 0. The standard product was determined by measuring the power supply of the wireless power receiver in the field with the power turned off. On the other hand, if the Mode 702 field is set to binary '01', the quality factor value is recorded. In the first data 701 field, the power supply of the wireless power receiver is turned off. The reference inductance value determined by the determination is recorded, and the reference quality factor value 703 field is The reference quality factor is determined by measuring the wireless power receiver when it is turned off. The value is recorded.

[0273] In this embodiment, the foreign substance detection device (or wireless power transmission device) and obtaining at least one of a reference quality factor value and a reference inductance value corresponding to the input receiver. It is possible.

[0274] FIG. 7c is a block diagram illustrating a message structure of an FOD status packet according to another embodiment of the present invention. This is a diagram of the

[0275] Referring to FIG. 7c, the FOD status packet message 700 has a length of 2 bytes. Reserved 701 field, 6 bits long, 2 bits long Mode 702 field and 1 byte length Reference The reservation 701 field may include a reservation value 703 field. All bits in the field are recorded as '0'.

[0276] As shown by reference numeral 704, the mode 702 field is set to binary '00'. For example, the reference value 703 field is the value measured when the power of the wireless power receiver is turned off. The reference quality factor value determined by the above is recorded. If set to '01', the reference value 703 field indicates that the power supply of the wireless power receiver is OF The reference inductance value determined by measuring at F is recorded.

[0277] In this embodiment, the foreign substance detection device (or wireless power transmission device) Obtain at least one of a reference quality factor value and a reference inductance value corresponding to the power receiver. It is possible.

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

[0279] Referring to FIG. 8a, if an object is detected in step 810, the foreign object detection device selects a resonator. After measuring and storing the quality factor values ​​of the circuit, a ping step 820 can be entered. In step 820, the foreign substance detection device detects a predetermined power signal for identifying the wireless power receiver. For example, a digital ping may be transmitted periodically.

[0280] The foreign object detection device receives a signal strength indicator corresponding to the digital ping in a ping step 820. If the wireless power receiver is received, the process proceeds to an identification and configuration step 830 to identify the wireless power receiver and Various configuration parameters for the line power receiver can be set.

[0281] Once the identification and configuration of the wireless power receiver is completed, the foreign object detection device proceeds to negotiation step 840. and receives an FOD status packet including a reference quality factor value.

[0282] The foreign matter detection device determines whether foreign matter is present based on the reference quality factor value included in the FOD status packet. A critical value (or critical range) for determining the presence or absence is determined, and the stored quality factor value is determined. The critical value (or critical range) determined by the test is compared to determine whether a foreign substance is present in the charging area. This can be done.

[0283] As explained in FIG. 6a, when the wireless power receiver has a low reference quality factor value, the charging area If a foreign object is placed in the The ratio is relatively small or low compared to wireless power receivers with a large ratio. According to an embodiment of the present invention, the foreign substance detection device detects a reference quality factor value received from a wireless power receiver. Therefore, the threshold value (or threshold range) for detecting foreign matter can be adaptively determined.

[0284] If the foreign object is present, the foreign object detection device stops the power transmission. On the other hand, if the result of the determination is that no foreign matter is present, the foreign matter detection device The power transmission step 850 is entered to start wireless charging of the corresponding wireless power receiver. Cut.

[0285] FIG. 8b illustrates a state transition process for detecting a foreign substance in the foreign substance detection device according to an embodiment of the present invention. FIG.

[0286] Referring to FIG. 8b, if an object is detected in step 810, the foreign object detection device selects a resonator. After measuring and storing the quality factor value and the inductance value of the circuit, the process proceeds to the ping step 820. In the ping step 820, the foreign object detection device pings the wireless power receiver to identify the wireless power receiver. For this purpose, a predetermined power signal, for example a digital ping, may be periodically transmitted.

[0287] If a signal strength indicator is received in ping step 820, the foreign object detection device identifies and configures In step 830, the wireless power receiver is identified, and various settings for the identified wireless power receiver are performed. You can set the configuration parameters.

[0288] Once the identification and configuration of the wireless power receiver is completed, the foreign object detection device proceeds to negotiation step 840. and a FOD state packet including a reference quality factor value and / or a reference inductance value is sent to the It is possible to receive the

[0289] The foreign object detection device determines whether a foreign object is present based on the reference value (etc.) included in the FOD status packet. Determine the critical value (or critical range) for judging the presence or absence, and Based on the result, it is possible to determine whether a foreign object is present in the charging area.

[0290] If the foreign object is present, the foreign object detection device stops the power transmission. On the other hand, if the result of the determination is that no foreign matter is present, the foreign matter detection device The power transmission step 850 is entered, and wireless charging of the corresponding wireless power receiver can be started. Before entering the power transmission stage 850, the foreign substance detection device performs the steps as described above with reference to FIG. Additionally, a correction step 250 may be performed.

[0291] FIG. 9a is a diagram illustrating a method for detecting a foreign object in a wireless power transmission device according to another embodiment of the present invention. 1 is a flowchart for

[0292] Referring to FIG. 9a, when an object is detected on the charging area in the selection stage, the wireless power transmitting device For example, the quality factor value of the resonant circuit can be measured and stored in a predetermined recording area (S901). .

[0293] The wireless power transmission device can check whether a foreign object has been previously detected. (S902).

[0294] If the check result shows that no foreign object is detected, the wireless power transmitter proceeds to the ping stage. It can wirelessly transmit a digital ping signal to identify the wireless power receiver. (S903).

[0295] When the wireless power transmitter receives a signal strength indicator corresponding to the digital ping signal, The identification and configuration stage is entered, and when the identification and configuration of the wireless power receiver are completed, the negotiation stage is entered. The user can then transition to the next floor (S904).

[0296] The wireless power transmitter uses the reference quality factor included in the FOD status packet received in the negotiation stage. Determine the critical value (or critical range) for determining the presence or absence of foreign matter based on the value of the Here, the method of determining the critical value and the critical range is the same as that shown in FIG. The wireless power transmission device wirelessly transmits a power signal of a predetermined strength in the negotiation stage. It can be sent out in

[0297] The wireless power transmitter compares the stored quality factor value with the determined critical value (or critical range). Then, it can be determined whether a foreign object is present on the charging area (S906).

[0298] If it is determined that a foreign object is present, the wireless power transmitting device stops transmitting the power signal and The device can be controlled to output a predetermined warning alarm indicating that a (S907 to S908). Then, the wireless power transmitting device returns to step 901. This can be done.

[0299] If it is determined in step 906 that no foreign object is present, the wireless power transmitting device transmits power. The wireless power receiver can then start charging (S909). .

[0300] If the foreign object has already been detected as a result of the check in step 902, The device may determine whether the detected foreign object has been removed from the charging area (S910 Here, the method of determining whether the detected foreign matter has been removed from the charging area is the same as that described above. Replace with the explanation of Figs. 6a to 8b.

[0301] If the detected foreign object is removed, the wireless power transmitter proceeds to the power transmission step. You can then restart charging the wireless power receiver.

[0302] If the foreign object detected in step 910 is not removed, the wireless power The transmitting device can perform the above-mentioned step 901.

[0303] FIG. 9b is a diagram illustrating a method for detecting a foreign object in a wireless power transmission device according to another embodiment of the present invention. 1 is a flowchart for

[0304] Referring to FIG. 9b, when an object is detected on the charging area in the selection stage, the wireless power transmitting device For example, the quality factor value and / or the 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 has been detected (S90 2).

[0306] If the check result shows that no foreign object is detected, the wireless power transmitter proceeds to the ping stage. It can wirelessly transmit a digital ping signal to identify the wireless power receiver. (S903).

[0307] When the wireless power transmitter receives a signal strength indicator corresponding to the digital ping signal, The identification and configuration stage is entered, and when the identification and configuration of the wireless power receiver are completed, the negotiation stage is entered. The user can then transition to the next floor (S904).

[0308] The wireless power transmitter determines whether a foreign object is present based on the FOD status packet received during the negotiation phase. A critical value (or critical range) for determining the presence or absence can be determined (S905). Here, the critical values ​​may include an inductance critical value and a quality factor critical value. If the value is within the critical range, the critical range includes the inductance critical range and the quality factor critical range. The wireless power transmission device can wirelessly transmit a power signal of a predetermined strength during the negotiation stage. can.

[0309] The wireless power transmitting device compares the stored measurement value with the determined critical value (or critical range). It can be determined whether a foreign object is present on the charging area (S906).

[0310] If it is determined that a foreign object is present, the wireless power transmitting device stops transmitting the power signal and The device can be controlled to output a predetermined warning alarm indicating that a (Optional) (S907 to S908). After that, the wireless power transmitting device performs the above-mentioned 901 step. You can return to the previous level.

[0311] If it is determined in step 906 that no foreign object is present, the wireless power transmitting device transmits power. The wireless power receiver can then start charging (S909). .

[0312] If the foreign object has already been detected as a result of the check in step 902, The device may determine whether the detected foreign object has been removed from the charging area (S910). Here, whether the detected foreign matter has been removed from the charging area is determined in step 901. The quality factor value and inductance value of the resonant circuit determined in step 905 and the critical value ( or critical range), but is not limited thereto.

[0313] If the detected foreign object is removed, the wireless power transmitter proceeds to the power transmission step. You can then restart charging the wireless power receiver.

[0314] If the foreign object detected in step 910 is not removed, the wireless power The transmitting device can perform the above-mentioned step 901.

[0315] As described above, the wireless power transmitting apparatus according to the present invention detects an object in the selection step. If so, the quality factor and inductance values ​​of the resonant circuit can be measured (or The threshold value is calculated based on the FOD status packet received during the negotiation phase. By comparing the values ​​to determine whether or not a foreign substance is present, the probability of failing to detect a foreign substance is greatly reduced. The advantage is that it can be kept low.

[0316] FIG. 10 shows the results of the test for each receiver type when a foreign object is placed in the charging area according to an embodiment of the present invention. 13 is a graph showing experimental results showing the degree to which a perceived quality value decreases compared to a reference quality factor value.

[0317] The experimental results shown in Figure 10 are those when a 10-cent coin is placed in the charging area. .

[0318] Referring to reference numerals 1010 and 1030 in FIG. 10, a 10-cent coin is placed in the charging area. After placing the diff1, the absolute amount by which the quality factor value drops compared to the reference quality factor value is It shows that the quality factor increases as the quality factor value increases. The quality factor (NO_FO) value measured at the time of measurement, i.e., the reference quality factor (RFQ) value and d The relationship of iff1 can be approximated by the formula of reference numeral 1011. No. 1011 is approximated by a quadratic equation, but this is only one example. Linear equations, etc. It should be noted that the equations can be approximated by higher-order equations, exponential equations, etc. do not have.

[0319] Referring to reference numerals 1020 and 1030 in FIG. 10, a 10-cent coin is placed in the charging area. After the setting, the ratio of the quality factor value decrease (%diff1) compared to the reference quality factor value is the reference quality factor value. It shows that the factor value increases as the value increases. In this case, if no foreign material is placed, The measured quality factor (NO_FO) value, i.e. the reference quality factor (RFQ) value and the %dif The relationship of f1 can be approximated by the equation of reference numeral 1021. 021 is approximated by a quadratic equation, but this is only one example. Note that it can also be approximated by quadratic equations, exponential equations, etc. .

[0320] FIG. 11 illustrates a receiver type 100 when a foreign object is placed in the charging area according to another embodiment of the present invention. 13 is a graph showing experimental results showing the degree to which a perceived quality value decreases compared to another reference quality factor value;

[0321] The experimental results shown in Figure 11 are for when a 25-cent coin is placed in the charging area. .

[0322] Referring to reference numerals 1110 and 1130 in FIG. 11, a quarter coin is placed in the charging area. After placing the diff2, the absolute amount by which the quality factor value drops compared to the reference quality factor value is It shows that the quality factor increases as the quality factor value increases. The quality factor (NO_FO) value measured at the time of measurement, i.e., the reference quality factor (RFQ) value and the di The relationship between ff2 and ff3 can be approximated by the formula 1111. 1111 is approximated by a quadratic equation, but this is only one example. It should be noted that it can be approximated by higher order equations, exponential equations, etc. stomach.

[0323] Referring to reference numerals 1120 and 1130 in FIG. 11, a quarter coin is placed in the charging area. After the adjustment, the percentage of the quality factor value that decreases compared to the reference quality factor value (%diff2) is the standard quality factor value. It shows that the factor value increases as the value increases. In this case, if no foreign material is placed, The measured quality factor (NO_FO) value, i.e., the difference between the reference quality factor (RFQ) value and The relationship between the two can be approximated by the equation 1121. 21 is approximated by a quadratic equation, but this is only one example. It can be approximated by a linear equation or other higher order equations. It should be noted that the equations may be approximated by equations, exponential equations, etc.

[0324] As described above, the wireless power transmitting apparatus according to the present invention detects an object in the selection step. If so, the quality factor value of the resonant circuit can be measured (or calculated) before entering the ping stage, and The measured quality factor value is compared to a critical value determined based on the received FOD status packet. By judging the presence or absence of foreign matter, the probability of failing to detect foreign matter is significantly reduced. This has the advantage that

[0325] Figure 12 shows the quality factor and inductance of the resonant circuit depending on the presence or absence of foreign matter for each receiver type. The measurement results of the transverse current are shown.

[0326] Reference numeral 1210 denotes a state where nothing is placed in the charging area 1211, and only a foreign substance is placed. The resonant circuit was measured in the state where only the receiver was placed (1212) and the state where only the receiver was placed (1213). The inductance value (Ls), resistance value (Rs) and quality factor value (Q) are shown.

[0327] Reference numeral 1220 denotes a receiver type in which a foreign object and a receiver are placed together in a charging area. The inductance value (Ls), resistance value (Rs) and quality factor value ( Q).

[0328] Referring to the reference numeral 1211, there is nothing placed on the charging bed of the wireless power transmission device. The inductance of the resonant circuit measured in the empty pad state was 25.20μm. H and has a quality factor value of 133.8.

[0329] Referring to the reference numeral 1210, when nothing is placed in the charging area, a foreign object, e.g. When foreign objects, such as FO#4 and a dime, are placed, the inductance value decreases. On the other hand, there are receivers that can receive wireless power even when there is nothing placed in the charging area, such as For example, when a receiver including a smartphone equipped with a wireless charging module is placed, The inductance value increases.

[0330] Also, referring to reference numeral 1210, when nothing is placed in the charging area, a foreign object is In particular, when the receivers are placed, the quality factor values ​​all decrease. In this case, the quality factor value is lower than that in FO#4.

[0331] Referring to the reference numeral 1220, a standard foreign material is placed in the charging area with the receiver placed therein. If FO#4 and 10-cent copper coins are also placed, the drawing numbers are 1221 and 1 As shown in Fig. 222, both the inductance value and the quality factor value are lower. The rate at which the coherence and quality factor values ​​drop varies with the type of receiver. Referring to surface reference numbers 1213, 1221 and 1222, in the case of receiver 1, the foreign matter is further When the inductance is increased, the change in the quality factor is larger than the change in the inductance. Therefore, in the case of receiver 1, the quality is determined based on the inductance value to determine whether or not a foreign substance is present. It may be advantageous to sense changes in the factor values. On the other hand, in the case of receiver 4, the foreign matter may be further When the inductance is increased, the change in the inductance value is larger than the change in the quality factor value. Therefore, in the case of the receiver 4, in order to determine whether or not there is a foreign substance, the inductor It may be advantageous to sense changes in the sense value.

[0332] It is possible to identify what type of receiver is placed in the charging area. This is possible in the configuration phase. Therefore, after detecting an object in the selection phase, before entering the ping phase, Therefore, the wireless power transmitter cannot identify the type of the receiver.

[0333] Therefore, in the wireless power transmitting apparatus according to the embodiment of the present invention, when an object is detected in the selection step, If so, all the inductance and quality factor values ​​of the resonant circuit are measured before entering the ping stage. It can be stored as such.

[0334] Then, the wireless power transmitter may transmit different FOD status packets based on the FOD status packets received during the negotiation phase. The inductance and quality factor thresholds for material sensing can be determined. The line power transmitter uses the determined critical value to calculate the inductance value and the quality factor value that have already been stored. It is possible to determine whether or not a foreign substance is present by comparing the measured value with the measured value.

[0335] In one example, the wireless power transmission device may compare the stored inductance value with the determined inductance value. The presence of foreign matter is judged by comparing the critical value of the tank with the stored quality factor value. If it is determined that a foreign substance is present by comparing it with the quality factor critical value set, the charging area is It can be determined that a foreign substance is placed in the

[0336] In the above embodiment, the wireless power transmission device detects a foreign object based on the FOD status packet. However, this is merely an example and the critical range is not necessarily a specific one. In this case, the wireless power transmission device can determine the range of the stored inductance If the value and / or quality factor value falls outside the determined critical range, it is determined that foreign matter is present. It is also possible.

[0337] According to another embodiment of the present invention, a method for detecting a foreign object in a wireless power transmission device includes: The method may further include receiving a received power intensity packet for power correction from the received power intensity packet. At this time, the received power intensity packet is the received power intensity of the wireless power receiver corresponding to the light load. The received power of the wireless power receiver corresponding to the power or load connection state can be included.

[0338] FIG. 13a illustrates a message structure of an FOD status packet according to yet another embodiment of the present invention. This is a diagram for clarification.

[0339] Referring to FIG. 13a, the FOD status packet message 1340 has a length of 1 byte. The operating frequency for the maximum quality factor value of 6 bits can be calculated. g Frequency for Maximum Quality Factor V alue 1340 field and 2-bit long mode 1342 field It may comprise

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

[0341] According to yet another embodiment of the present invention, a wireless power transmitter is provided having an operating frequency having a maximum quality factor value. The quality factor peak operating frequency of the band above the ping phase (the sum of the quality factor values ​​measured before the ping phase) If there exists a certain operating frequency at which the maximum quality factor value is measured, it means that there is a foreign object in the charging area. It can be determined that:

[0342] As an example, the operating frequency 1341 for the maximum quality factor value is determined by the identification and configuration step 23 of FIG. 0 at the operating frequency for the maximum quality factor value corresponding to the type of wireless power transmitter identified As an example, a wireless power transmitter type that can be connected to the wireless power receiver for this purpose may be used. Operating frequency information for another maximum quality factor value may be maintained in a predetermined recording area. The operating frequency for the maximum quality factor value depends on the power class, design, manufacturing Varies depending on company, standards applied, etc.

[0343] Therefore, what operating frequency or what operating frequency range is relevant to the wireless power receiver? If it is confirmed that the wireless power transmitter has the maximum quality factor value, the wireless power transmitter checks for the presence of foreign matter. The frequency range in which the quality factor value must be measured to find the That is, the wireless power transmitter must be in a frequency band lower than the operating frequency for the maximum quality factor value. Therefore, it is not necessary to perform a quality factor value measurement for the corresponding

[0344] As another example, the operating frequency for the maximum quality factor value 1341 is defined in the WPC standard A coil type that may be, but is not limited to, a specific coil type, for example, MP-A1 type. The operating frequency for the maximum quality factor value corresponding to the wireless power transmitter equipped with the transmitting coil of the It can also be a frequency. This is based on the MP-A1 type, and other types of wireless power transmitters The magnitude of the maximum quality factor value received is adjusted (sca) taking into account design differences and product characteristics. This can be used to determine whether or not foreign matter is present.

[0345] The wireless power transmitter according to an embodiment of the present invention performs the ping step 220 (or the ping step 230) of FIG. (a) measures and stores a quality factor value a1 for a specific upper limit frequency of the operating frequency band. Or, it can be measured within a frequency range that has already been set (within the operating frequency range). The maximum quality factor among the quality factors and the frequency at which the maximum quality factor is measured can be stored. The wireless power transmitter then notifies the FOD status packet 1340 during the negotiation phase 240. Measure the quality factor value a2 at the operating frequency 1341 for the maximum quality factor value received by If a1 is greater than a2, it can be determined that a foreign substance is present in the charging area. The wireless power transmitter receives the FOD status packet 1340 during the negotiation phase 240. The operating frequency and the measured quality factor at the ping stage 220 (or before the ping stage) for the maximum quality factor value obtained. The presence or absence of foreign matter can be determined by comparing the maximum quality factor measured with the measured frequency. .

[0346] The maximum quality factor measured in the ping step 220 is the maximum quality factor measured for the frequency received. If the frequency is greater than the factor operating frequency, it can be determined that a foreign substance is present. This is explained in more detail below.

[0347] In this embodiment, the wireless power transmitter is set to the operating frequency in the ping phase 220 (or before the ping phase). It is also possible to measure only the quality factor value for the upper frequency limit of the band, but this is one embodiment. In another embodiment, the quality factor values ​​for both the lower and upper frequency limits are measured. Yet another embodiment is to sweep from a lower limit frequency to an upper limit frequency and The quality factor value for each frequency can be measured.

[0348] In still another embodiment, the quality factor value for each frequency is measured by sweeping within a specific frequency range. It can be determined.

[0349] In the ping step 220, the wireless power transmitter receives a quality factor for the lower limit frequency of the operating frequency band. In this embodiment, the wireless power transmitter is defined to measure the ping step 22. It is also possible to measure only the quality factor value for the upper limit frequency of the operating frequency band by setting it to 0, This is just one embodiment, other embodiments may use different quality factor values ​​for lower and upper frequency limits. can also be measured.

[0350] In one embodiment, the operating frequency for maximum quality factor value 1341 field is The lower limit frequency, i.e., the frequency offset value from the lowest frequency, can be recorded. Here, the offset unit can actually mean 10KHz, but is not limited to this. It may be smaller or larger than that. The frequency band is between the lower limit frequency of 100KHz and the upper limit frequency of 300KHz, and the offset The frequency is 10KHz and the maximum quality factor value is recorded in the operating frequency 1341 field. If the value entered is binary 000011, then the frequency for the maximum quality factor value is actually 130K. Hz (100KHz+3*10KHz).

[0351] In yet another embodiment, the wireless power transmitter may be configured to transmit the entire operating frequency band or the entire It is possible to measure the quality factor value by sweeping a specific frequency band within the operating frequency band. can.

[0352] In yet another embodiment, the filter in FIG. 13a is inserted for the operating frequency for the maximum quality factor value. Instead of field 1341, the quality factor is increased by the value (or ratio) already set from the reference quality factor value. An operating frequency value at which the child value is lower can also be inserted into field 1341 .

[0353] The wireless power transmitter may be configured to operate at a reference operating frequency (e.g., , the operating frequency for measuring the quality factor value is 100 kHz) a quality factor value B2 measured at an operating frequency greater than the received operating frequency; By comparing, it is possible to determine whether or not a foreign substance is present.

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

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

[0356] Referring to FIG. 13b, the FOD status packet message 1350 has a length of 2 bytes. The operating frequency for the maximum quality factor value of 6 bits can be calculated. g Frequency for Maximum Quality Factor V alue 1351 field, 2-bit long mode 1352 field and 1 byte of Reference Quality Factor value r Value) 1353.

[0357] The wireless power transmitter shall report the maximum quality of the received FOD status packet by the mode 1352 value. You can also check whether the operating frequency 1351 for the quality factor value is included, but only The maximum quality factor is always applied to FOD status packets regardless of the mode 1352 value. An operating frequency 1351 for the child value may also be included.

[0358] When the wireless power transmitter receives the FOD status packet of FIG. 7a, it sets the reference quality factor value and pin The quality factor values ​​measured in the ping step 220 (or before the ping step) are compared to determine whether or not foreign matter is present. You can also determine the maximum quality factor value for your operating frequency and ping (method 1). The maximum operating frequency corresponding to the maximum quality factor value measured in step 220 (or before the ping step) It is also possible to determine whether or not a foreign substance is present by comparing the two (Method 2, embodiment of FIG. 13a).

[0359] Alternatively, the presence or absence of foreign matter can be determined using a combination of methods.

[0360] In one embodiment, the wireless power transmitter can determine whether or not a foreign object is present using method 1. When the reference quality factor value is received, two thresholds (threshold 1: Q_Thresh old1 and threshold 2: Q_Threshold2) can be determined. Threshold 1 has a value higher than the critical value 2.

[0361] If the quality factor value measured before the ping step 220 is less than the critical value 2, the wireless power transmission The machine can determine that a foreign substance is present.

[0362] Is the quality factor value measured before the ping step 220 smaller than the critical value 1 and equal to the critical value 2? If it is larger than that, the wireless power transmitter can determine whether or not a foreign object is present using Method 2. do.

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

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

[0365] The wireless power transmitter shall set the wireless power according to the received FOD status packet according to the Mode 1362 value. Includes transmitter type 1361 information and operating frequency 1363 information for maximum quality factor value However, it is not limited to this, regardless of the mode 1362 value, The FOD status packet always contains the wireless power transmitter type 1361 information and the maximum quality factor value. Operating frequency 1363 information for the purpose of the present invention may also be included.

[0366] As an example, the wireless power transmitter type 1361 is a wireless A predefined transmitter design number (Tx Design Number) to uniquely identify the power transmitter. It may be a value (a predetermined classification number) indicating the size (umber).

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

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

[0369] According to yet another embodiment of the present invention, a wireless power transmitter is provided having an operating frequency having a maximum quality factor value. Peak operating frequency (quality factor measured before the ping stage) If there is a foreign object in the charging area, the operating frequency at which the maximum quality factor value is measured exists. It can be determined that quality is present.

[0370] For the sake of convenience, the reference quality factor value measured when no foreign matter is present is referred to as R QF_NO_FO, the quality factor value measured when a specific foreign substance is present is QF_FO. As an example, a particular foreign object is an aluminum alloy with a diameter of 22 mm and a thickness of 1 mm. Foreign Object #4, a miniature disk (hereafter, for the sake of convenience, (used in combination with FO4), but is not limited to this, and can be any commonly used copper coin. You can use either one.

[0371] Before the wireless power transmitter performs the ping step, i.e., in the selection step, it measures the current quality factor value. The wireless power transmitter determines the reference quality factor value ( Reference Quality Factor Value) and transmitter-specific design Production and measurement error values ​​to take into account technical differences ourement tolerance and the reference quality factor Accuracy f Reference Quality Factor) A quality factor critical value for determining nullity is determined.

[0372] The reference quality factor was calculated using a test power transmitter (TPT). tter), for example, 5 areas (middle) of the charging area of ​​MP1 (MP-A1) type transmitter The minimum quality factor value measured at the four positions (the middle position and the four positions shifted 5 mm left / right / up / down) This means that the design differences between the MP1 test power transmitter and commercial wireless power transmitters, such as For example, the quality factor measured in the charging area due to differences in the inductance value of the transmitting coil The value varies from transmitter to 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 quality factor 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 matter 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). However, the present invention is not limited to this. As an example, the reference quality factor drop value 1321 is calculated by the following Equation 1: It can be done.

[0375] Formula 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 does not reflect *100. value)

[0379] The standard quality factor drop value for wireless power receivers varies depending on the manufacturer and / or product type. .

[0380] Therefore, the wireless power transmitter according to an embodiment of the present invention detects the reference quality factor drop value. The quality factor drop value is obtained from the wireless power receiver and the presence or absence of foreign matter is determined based on the reference quality factor drop value. In this way, the quality factor critical value for the quality factor can be adaptively determined.

[0381] Therefore, the present invention is capable of detecting the presence of foreign matter in the charging area even though the foreign matter is actually located in the charging area. This minimizes the problem of heat generation and a dramatic drop in power transmission efficiency due to the device not being detected. Cut.

[0382] FIG. 13d illustrates a message structure of an FOD status packet according to one embodiment of the present invention. This is a diagram of the

[0383] Referring to FIG. 13d, the FOD status packet message 1300 has a length of 2 bytes. 6-bit long reserved 1301, 2-bit long model Mode 1302 field and 1-byte length reference quality factor value The quality factor value (QFV) may comprise 1303. do.

[0384] All bits that make up the Reserved 1301 field can be set to zero.

[0385] Referring to drawing reference numeral 1304, if the mode 1302 field is binary '00', The reference quality factor without FO (RQF_NO_FO, the first reference quality factor) is the reference quality factor. The quality factor value is recorded in the 1303 field, and the mode field is If the digit is '01', the reference quality factor in the presence of FO (RQF_FO, the second reference quality factor This may mean that the reference quality factor value 1303 is recorded in the reference quality factor value 1303 field.

[0386] FIG. 13e is a block diagram illustrating a message structure of an FO status packet according to another embodiment of the present invention. This is a diagram of the

[0387] Referring to FIG. 13e, the FO Status Packet message 1310 has a length of 3 bytes. 6-bit long reserved 1311, 2-bit long mode Mode 1312 field, Reference Quality Factor value ty Factor Value)1313 and Reference Quality Factor Value when Foreign Substances are Present (Ref erence Quality Factor Value With Foreign Object) 1314.

[0388] All bits that make up the Reserved 1301 field can be set to zero.

[0389] Power reception to which the corresponding reference quality factor value 1313 is applied via the mode 1312 field The operation mode of the device can be identified. Referring to reference numeral 1315, mode 13 If the value of 12 is binary '00', it is the reference value measured with the wireless power receiver powered off. It means that it is a quality factor value.

[0390] The wireless power receiver is measured when there are no foreign substances by manufacturer or (and) product type. The reference quality factor value measured when a foreign substance is present differs from the reference quality factor value measured when a foreign substance is present.

[0391] The wireless power transmitter according to an embodiment of the present invention is a reference power transmitter that is measured when no foreign matter is present. The presence or absence of foreign matter is judged by taking into account the quality factor value and the reference quality factor value measured when foreign matter is present. The quality factor threshold for determining the absence of a signal can be adaptively determined. This is because the amount of change in the quality factor value differs depending on the presence of foreign matter. This occurs because the foreign object is not detected properly even though it is actually located in the charging area. This can minimize problems such as overheating and a drop in power transmission efficiency.

[0392] FIG. 13f illustrates a message structure of an FO status packet according to yet another embodiment of the present invention. This is a diagram for explaining the method.

[0393] Referring to FIG. 13f, the FO Status Packet message 1120 has a length of 2 bytes. The Drop Value of Re is a 6-bit long reference Interference Quality Factor) 1321 field, 2 bits long Mode 1322 field, Reference Quality Factor value It comprises 1323 fields (Lity Factor Value).

[0394] Here, the reference quality factor drop value 1321 is the reference quality factor measured when no foreign matter is present. The quality factor value measured when the factor value 1223 and specific foreign substances were present (Quality Factor The ctor value with foreign object is used as the basis for the The value can be any value.

[0395] The Mode 1322 field corresponds to the reference quality factor drop value in the Reserved 1301 field of FIG. 13d. 1321 can be used to indicate that a recording is being made. Referring to the plane code 1324, if the value of the mode 1322 field is binary '01', This can mean that the reference quality factor drop value 1321 is recorded in the reserved field. However, this is only one example and other values ​​for the mode 1322 field are possible, e.g., binary '10' or binary '11' is recorded in the reserved field as the reference quality factor drop value 1321. It can also be used to indicate that

[0396] However, if the mode 1322 field value is set to a value other than binary '00', The reference quality factor value 1323 is a value measured when the power of the power receiver is OFF. It can be automatically included.

[0397] For convenience of explanation, the format of the foreign object status packet according to the mode in the specific embodiment is as follows: Although the description was made in two ways, the foreign substance state packet is the same as that shown in Figs. 13d to 13g regardless of the mode. It may be in the form of an embodiment.

[0398] FIG. 13g illustrates a message structure of an FO status packet according to yet another embodiment of the present invention. This is a diagram for explaining the method.

[0399] Referring to FIG. 13g, the FO Status Packet message 1330 has a length of 2 bytes. The accuracy of the reference quality factor (Accuracy of Reference Quality Factor) is 6 bits long. Mode Quality Factor (MQF) 1331 field, 2 bits long Mode 1332 field and Reference Quality Factor value The QoS Factor Value (QQL) 1333 field can be included.

[0400] Here, the reference quality factor accuracy 1331 is the reference quality measured when no foreign matter is present. It may be an error tolerance for the factor value 1333. As an example, the error tolerance is applied The reference quality factor value is increased compared to the reference quality factor value 1333 received from the wireless power receiving device. The ratio may be set to, but is not limited to, an increase or decrease ratio.

[0401] The standard quality factor accuracy 1331 varies depending on the manufacturer (or) and product type of the wireless power receiver. For example, a wireless power receiver from company A and a wireless power receiver from company B may have different values. The receiver works with the same wireless power transmitter, and the accuracy of the measured reference quality factor value is different. Therefore, the wireless power transmitter obtains information about the accuracy of the standard quality factor for each wireless power receiver. It is necessary to obtain a quality standard to determine the presence or absence of foreign matter, taking into account the accuracy of the quality factor. The factor critical value can be determined. In addition, the wireless power transmitter is described below for convenience of explanation. FO_QF_THRESH is a simple way to determine the quality factor threshold for determining whether or not foreign matter is present. I decided to name it OLD.

[0402] For example, the test results for the same wireless power transmitter and the wireless power receiver of company A The measured reference quality factor value is 100, the reference quality measured for the wireless power receiver of company B The factor value may be 70. In this case, the reference quality factor corresponding to the wireless power receiver of company B is For example, the standard quality factor accuracy of the wireless power receiver of company A is within + / -7%. For example, it can be set higher than + / - 10%. In other words, the sensitivity to error is The wireless power receiver of company B can be set higher than that of company A.

[0403] Thus, the quality factor accuracy may vary depending on the configuration of the finished product in which the receiver is installed. For example, PCBs, camera modules, antennas and other components that are attached to the finished product. The quality factor of a part may be measured lower than other finished products even when no foreign matter is present. This allows the finished product located in the charging area together with the foreign matter to be charged with other finished products. The difference in quality factor values ​​may be small compared to the product, so higher measurement accuracy is required. will be done.

[0404] The Mode 1332 field is the reference quality factor accuracy in the Reserved 1301 field of FIG. 13d. 1331 can be used to indicate that a recording is being made. Referring to the plane code 1334, if the value of the mode 1332 field is binary '01', This could mean that the reference quality factor accuracy 1331 is recorded in a reserved field. However, this is only one example and other values ​​for the mode 1332 field are possible, e.g., binary '10' or binary '11' is recorded in the reserved field for the reference quality factor accuracy 1331. It can also be used to indicate that

[0405] However, if the mode 1332 field value is set to a value other than binary '00', The reference quality factor value 1333 is a value measured when the power of the power receiver is OFF. It can be automatically included.

[0406] FIG. 14 is a flow chart illustrating a method for detecting FOD according to another embodiment of the present invention. be.

[0407] Referring to FIG. 14, in the negotiation phase, the wireless power receiver 1410 determines a second reference quality factor value (S econd Reference Quality Factor Value, RQF _FO) to the wireless power transmitter 1420. At this time, the Mode value of the FOD status packet is set to the binary number "0 1”.

[0408] The second reference quality factor value is measured at multiple points on the charging area of ​​a specified wireless power transmitter. A value having a minimum value among the determined quality factor values ​​is determined and maintained in the wireless power receiver. can be done.

[0409] As an example, the second reference quality factor value (RQF_FO) is With FO present near the aircraft, the transmitter coil (Primary Coil) and receiver coil The first quality factor measured at the central position where the (Secondary Coil) is well aligned With the value and FO around the wireless power receiver, the wireless power receiver is rotated from the center without rotation. A fixed distance offset (e.g., + / - 5mm in the x and y directions, respectively) (including but not limited to) a minimum value of the second quality factor values ​​measured while moving is determined. wherein the second quality factor value is measured at at least four different locations. The quality factor value may include a

[0410] The wireless power transmitter 1420 receives the second reference quality factor value and FO detection based on the design factor stored in advance corresponding to For convenience of explanation, the following structure is The second reference quality factor value corrected based on the composition factor is set as the corrected quality factor critical value (Q_thres We will name it hold_correct).

[0411] The second reference quality factor value is a value determined by a specified wireless power transmitter (hereinafter, a test wireless power transmitter The quality factor is determined based on the measured quality factor values ​​on the A wireless power transmitter manufactured commercially for commercial use (hereinafter, for the sake of convenience, a wireless power transmitter manufactured commercially for commercial use) The test equipment (hereafter called the test equipment) may differ in configuration and characteristics from the test wireless power transmitter. Therefore, the quality factor values ​​measured under the same conditions are the same for commercial and test wireless power transmitters. Therefore, the threshold value used for FO detection in the embodiment of FIG. The second reference quality factor value takes into account the configuration and characteristics of commercial wireless power transmitters, i.e., configuration factors. It is necessary to correct for this.

[0412] As an example, the configuration factor may be the power class (Pc) corresponding to the applicable commercial wireless power transmitter. Class), characteristics and layout of the transmitting coil, power control algorithm installed in the transmitter Rhythm, Power Transfer Loss, Applicable wireless power transmitter a correction constant value determined based on at least one parameter of the shape and structure of However, the present invention is not limited to the above, and the measurement error of the quality factor value for the test wireless power transmitter is obtained. Any value that can be corrected is sufficient.

[0413] The wireless power transmitter 1420 measures the current quality factor value (Q_current) and The factor value (Q_current) is the corrected quality factor critical value (Q_threshod_corr ect) can be compared to see if they are greater than or equal to each other (S1403~S1404). .

[0414] For reference, the current quality factor value is measured before the Digital Ping stage. It can be determined before the (re)negotiation stage or it can be measured periodically. It is also possible.

[0415] As a result of the comparison, the current quality factor value (Q_current) is equal to or exceeds the corrected quality factor threshold value (Q_thr eshod_correct) or greater, the wireless power transmitter 1420 It is possible to determine that no FO is detected and transmit an ACK response to the wireless power receiver 1410. At this time, the state of the wireless power transmitter 1420 is changed from the negotiation stage to the power transmission stage (S1405). You can transition between stages.

[0416] As a result of the comparison of the 1404 steps mentioned above, the current quality factor value (Q_current) is the corrected quality If the factor is smaller than the threshold value (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. At this time, the state of the wireless power transmitter 1420 is changed from the negotiation stage to the You can move on to the selection stage.

[0417] FIG. 15 is a flow chart illustrating a method for detecting FOD according to another embodiment of the present invention. It is.

[0418] Referring to FIG. 15, in the negotiation phase, the wireless power receiver 1510 receives a reference quality factor value (Ref erence Quality Factor Value, Q_reference) to the wireless power transmitter 1520. Yes (S1501~S1502).

[0419] Here, the first FOD status packet is the first reference product when the mode is binary '00'. The second FOD status packet can contain a quality factor value (RQF_NO_FO). The second reference quality factor value (RQF_FO) when the mode is 1, i.e., when FO is in the charging region, The quality factor may include a reference quality factor value determined based on quality factor values ​​measured at existing conditions. Cut.

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

[0421] The first and second reference quality factor values ​​are respectively the state where FO is not in the vicinity of the receiver and the state where FO is in the vicinity of the receiver. The quality factor can be determined based on the quality factor value measured in the state around . The first and second reference quality factor values ​​are obtained by measuring the number of wireless power transmitters on a charging area of ​​a specific test wireless power transmitter. Among the quality factor values ​​measured at the points, the value having the minimum value can be determined.

[0422] The wireless power transmitter 1520 performs a FO detection based on the received first and second reference quality factor values. Quality Factor Threshold R Then, the Q_threshold_rate, Q_threshold_rate) can be determined (S1503).

[0423] Here, the quality factor critical rate (Q_threshold_rate) is the first criterion quality factor. The difference between the child value (RQF_NO_FO) and the second reference quality factor value (RQF_FO) is taken as the first reference It can be calculated by dividing by the quality factor value (RQF_NO_FO). 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 critical ratio (Q_threshold_rate) is (80-5 0) / 80=0.6375.

[0424] The wireless power transmitter 1520 measures a current quality factor value (Q_current) and The quality factor is reduced based on the current quality factor value and the first reference quality factor value (RQF_NO_FO). A decrease rate (Q_decrease_rate) can be calculated (S1404).

[0425] For reference, the current quality factor value is measured before the Digital Ping stage. It can be set at the beginning of the negotiation (renegotiation) phase, it can be measured just before the negotiation (renegotiation) phase, or it can be measured periodically. It can also be done.

[0426] The wireless power transmitter 1520 has a quality factor decrease rate (Q_decrease_rate) of 100%. It can be compared whether the quality factor is smaller than the Q_threshold_rate. Cut (S1505).

[0427] If the comparison result is smaller, the wireless power transmitter 1520 determines that FO is not detected and An ACK response can be transmitted to the power receiver 1510 (S1506). The state of the line power transmitter 1520 can transition from the negotiation phase to the power transmission phase.

[0428] The comparison result of the 1505 steps mentioned above shows the quality factor decrease ratio (Q_decrease_rat e) is equal to or greater than the quality factor critical rate (Q_threshold_rate) If so, the wireless power transmitter 1520 determines that an FO has been detected and notifies the wireless power receiver 1510 In this case, the wireless power transmitter 1520 can transmit a NAK response (S1507). The state of can transition from the negotiation phase to the selection phase.

[0429] In the example of FIG. 15, the quality factor decrease rate (Q_decrease_rate) and the quality factor It is explained that FO detection is performed by comparing the critical ratio (Q_threshold_rate). However, this is merely one embodiment, and a wireless power transmitter according to another embodiment of the present invention may be , the corrected quality factor critical ratio (Q_thr eshold_rate_correct) and calculate the quality factor reduction ratio (Q_decr ease_rate) and corrected quality factor critical ratio (Q_threshold_rate_c orrect) to determine whether FO is in the charging area.

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

[0431] The received Reference Quality Factor value alue) quality factor measurement error range (ex ±10% (0.61 * reference quality factor value), or Accuracy of Quality Factor Value (Fig. 19g) The transmitter characteristics (transmitter type (design), manufacturer, product or measurement error, etc.) are taken into consideration. can be determined.

[0432] FIG. 16 illustrates a quality factor table according to one embodiment of the present invention.

[0433] The quality factor table 1600 shown in FIG. 16 is maintained in the memory of the wireless power transmitter. The wireless power transmitter can then determine the quality factor table based on the received FO status packet. 600 can be updated. Child 1601 field, the most recently measured quality factor value (Latest Measure ed Quality Factor Value)1602 field, 1st standard quality Factor value (RQF_NO_FO) 1603 field, second reference quality factor value (RQF_FO ) 1604 field and correction quality factor critical value (Q_threshold_correc t) 1605) may comprise at least one of the fields.

[0434] Here, the receiver identifier 1601 is the manufacturer code (manufacturer code) obtained in the identification and configuration step. nufacturer code, Basic Device Identifier Identifier and Extended Device Identifier dentifier) ​​or a combination of at least one of them. For example, a receiver identifier can be created by concatenating a manufacturer code and a basic device identifier. As another example, the receiver identifier may be configured using a manufacturer code, a basic device identifier, It may also be constructed by concatenating an identifier and an extended device identifier.

[0435] The most recently measured quality factor value 1602 field contains the corresponding receiver identifier 1601 The most recently measured quality factor value may be recorded corresponding to the Charging for the wireless power receiver corresponding to the receiver identifier 1601 is normally completed or negotiation is performed. When a steady state transition to the power transmission state is made in the negotiation stage, the wireless power transmitter The quality factor values ​​measured on the floors may be recorded in a quality factor table 1600 .

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

[0437] In addition, the wireless power transmitter detects the FO during the initial negotiation with the wireless power receiver. The calculated corrected quality factor threshold value (Q_threshold_correct) is used as the quality factor test. It can also be recorded on Table 1600.

[0438] The wireless power transmitter will then correspond to the receiver identifier recorded in the quality factor table 1600. If a corresponding wireless power receiver is detected, the quality factor table 1600 is referenced to detect the FO. It is possible.

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

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

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

[0442] Referring to FIG. 17, the FO detection device 1700 includes a communication unit 1710, a determination unit 1720, a measurement unit 1730, and a The power supply unit 1700 includes a power supply unit 1710, a power supply unit 1720, a power supply unit 1730, a power supply unit 1740, a power supply unit 1750, and a power supply unit 1760. This can be done.

[0443] The communication unit 1710 receives the reference quality factor value from the wireless power receiver connected in the negotiation stage. The FOD status packet may be received, where the reference quality factor value is the Reference quality factor value when not in the region (RQF_NO_FO, first reference quality factor value) and and the reference quality factor value when FO is in the charging area (RQF_FO, the second reference quality factor value ) and during the negotiation phase, one FOD status packet or multiple This can be received via the FOD status packet.

[0444] The decision unit 1720 decides a threshold value to be used when detecting an FO based on the received reference quality factor value. For example, the threshold value used in FO detection can be the second reference quality factor value (R However, this is merely an example and other embodiments of the present invention may be used. The threshold value used in the FO detection according to the embodiment is based on the configuration factors corresponding to the wireless power transmitter. It may also be determined that the second reference quality factor value is corrected based on the above.

[0445] According to another embodiment of the present invention, the threshold values ​​used in detecting the FO are first and second reference qualities. The quality factor threshold ratio (Quality Factor Thr) calculated based on the factor values The threshold rate, Q_threshold_rate, can also be determined as do.

[0446] In the first embodiment, the quality factor critical rate (Q_threshold_rate) is the first standard The difference between the quality factor value (RQF_NO_FO) and the second reference quality factor value (RQF_FO) is calculated as the first It can be calculated by dividing by the reference quality factor value (RQF_NO_FO). 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 critical ratio (Q_threshold_rate) is (80-5 0) / 80=0.6375.

[0447] In the second embodiment, the quality factor critical rate (Q_threshold_rate) is the second standard The quality factor value (RQF_FO) is divided by the first reference quality factor value (RQF_NO_FO). The first reference quality factor value (RQF_NO_FO) is 80, the second reference quality factor value (RQF_NO_FO) is 80, When the quality factor value (RQF_FO) is 50, the quality factor critical ratio (Q_threshold_ The rate can be calculated as 50 / 80 = 0.6625.

[0448] According to another embodiment of the present invention, the threshold values ​​used in detecting the FO are first and second reference qualities. The factor value is calculated by applying a predetermined configuration factor corresponding to the corresponding wireless power transmitter. Corrected quality factor critical ratio calculated based on the first corrected reference quality factor and the second corrected reference quality factor (Q_threshold_rate_correct) can also be determined.

[0449] The measurement unit 1730 measures the current quality factor to be compared with the above-mentioned critical value when FO is detected. It can be measured or calculated.

[0450] For example, the measurement unit 1730 may measure a current quality factor value (Q_current) during the negotiation phase. It can be determined.

[0451] The measurement unit 1730 also measures the current quality factor value (Q_current) and the first base Based on the quasi-quality factor value (RQF_NO_FO), the quality factor reduction ratio (Q_decrease Here, we can calculate the quality factor decrease rate (Q_decrea se_rate) is [RQF_NO_FO-Q_current] / [RQF_NO_F O].

[0452] The measurement unit 1730 also measures the current quality factor value (Q_current) and the first base The ratio of the current quality factor (Q_current) based on the quasi-quality factor value (RQF_NO_FO) t_rate) can be calculated, where the current quality factor rate (Q_curre nt_rate) is calculated by [Q_current] / [RQF_NO_FO]. It is possible.

[0453] The detection unit 1740 detects the threshold value determined by the determination unit 1720 and the measurement value determined by the measurement unit 1730. By comparing the measured or calculated values ​​with those of the FO, it can be detected whether the FO is present in the charging area. do.

[0454] As an example, the detector 1740 may detect the current quality factor value (Q If the current (current) is less than the second reference quality factor (RQF_FO), the charging area is It can be determined that FO exists.

[0455] As another example, the detection unit 1740 may detect the current quality factor value ( Q_current is the corrected quality factor threshold (Q_threshold_correct ), it can be determined that FO exists in the charging area.

[0456] As yet another example, the detector 1740 may detect the quality factor reduction as shown in FIG. The small ratio (Q_decrease_rate) and the quality factor critical ratio (Q_threshol d_rate) to determine whether FO is present in the charging area.

[0457] As yet another example, the detector 1740 may detect a quality factor decrease ratio (Q_decrease_ The correction quality factor calculated based on the configuration factor corresponding to the wireless power transmitter The critical ratios can be compared to determine whether FO is present in the charging area.

[0458] As yet another example, the detector 1740 may determine the quality factor threshold as follows: Cut.

[0459] The received Reference Quality Factor value alue) quality factor measurement error range (ex±10%(0.61*referenceQ- FactorValue, or Accuracy of Quality Factor Value ity Factor Value (Figure 11d)) and transmitter characteristics (transmitter type (design The accuracy can be determined by taking into consideration the following:

[0460] The control unit 1750 can control the overall operation and input / output of the FO detection device 1700. As an example, the control unit 1750 may detect that the FO has not been detected by the detection unit 1740. In this case, the state of the corresponding wireless power transmitter is transitioned from the negotiation stage to the power transmission stage, and the power transmission unit 17 60 can be controlled to deliver the power required to charge the load. When the detection unit 1740 detects an FO, the control unit 1750 The state is transitioned from the negotiation phase to the selection phase, so that the power transmission unit 1760 is prevented from transmitting power. It can be controlled as follows.

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

[0462] In accordance with another embodiment of the present invention, an FO detection device 1700 detects an FO by the detection unit 1740. If FO is not detected, the wireless power receiver and the (wireless power transmitter) may further include a correction unit (not shown) for calculating a power loss between the do.

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

[0464] Referring to FIG. 18, in the negotiation phase, the wireless power receiver 1810 determines a reference quality factor value (Re reference Quality Factor Value) and reference quality factor drop value (Drop Value of Reference Quality Factor) The FOD status packet including the FOD status may be transmitted to the wireless power transmitter 1820 (S1 In this case, the Mode value of the FOD status packet is set to binary “01”. It can be set as, but is not limited to, the above.

[0465] Here, the reference quality factor value is the charging range of the specific wireless power transmitter designated for the performance test. The wireless power control unit 100 determines the wireless power control value as the minimum value of the quality factor values ​​measured at multiple points on the wireless power control area. The received signal can be stored in the receiver.

[0466] The wireless power transmitter 1820 uses the received reference quality factor value and the reference quality factor drop value to Quality Factor Threshold Value, Q _threshold) can be determined (S1803).

[0467] As an example, the wireless power transmitter 1820 may subtract the reference quality factor drop value from the reference quality factor value. The subtracted value can be determined as the quality factor critical value, but is not limited thereto. A given quality factor critical value generating function is given, where the reference quality factor value and the reference quality factor drop value are input variables. It can also be used to determine a quality factor critical value.

[0468] The wireless power transmitter 1820 measures the current quality factor value (Q_current) and The quality factor value (Q_current) is equal to or less than the quality factor critical value (Q_threshold). It is then possible to compare whether the value is greater than the other value (S1803 to S1804).

[0469] For reference, the current quality factor value is before the Digital Ping stage. It can be measured at the beginning or just before the negotiation (renegotiation) phase, and the digital pin It may also be measured periodically after the step of

[0470] As a result of the comparison, the current quality factor value (Q_current) is equal to or exceeds the quality factor threshold value (Q_thres hod), the wireless power transmitter 1820 determines that FO has not been detected. Then, the wireless power receiver 1810 can transmit an ACK response (S1805 At this time, the state of the wireless power transmitter 1820 transitions from the negotiation stage to the power transmission stage. This can be done.

[0471] As a result of the above 1804 step comparison, the current quality factor value (Q_current) is If the threshold value (Q_threshold) is less than the threshold value, the wireless power transmitter 1820 detects the FO. The wireless power receiver 1810 may then determine that the received signal has been received and transmit a NAK response to the wireless power receiver 1810 (S18 At this time, the state of the wireless power transmitter 1820 transitions from the negotiation phase to the selection phase. This can be done.

[0472] FIG. 19 is a flowchart illustrating a method for detecting FOD according to another embodiment of the present invention. be.

[0473] Referring to FIG. 19, in the negotiation phase, the wireless power receiver 1910 calculates the reference quality factor accuracy ( Accuracy of Reference Quality Factor and Includes Reference Quality Factor Value. The FOD status packet may be transmitted to the wireless power transmitter 1920 (S190 1) In this case, the Mode value of the FOD status packet is set to binary “01”. The present invention is not limited to the above.

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

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

[0476] In one example, the wireless power transmitter 1920 may generate a reference quality factor accuracy from the reference quality factor value. The quality factor critical value can be determined by subtracting the production and measurement errors, but is not limited to this. Another example is a predefined quality factor where the reference quality factor accuracy and the reference quality factor value are input variables. The quality factor critical value may also be determined using a factor critical value generating function.

[0477] The wireless power transmitter 1920 measures the current quality factor value (Q_current) and The quality factor value (Q_current) is equal to or less than the quality factor critical value (Q_threshold). It is possible to compare whether the value is greater than the other value (S1903 to S1904).

[0478] According to an embodiment of the present invention, the current quality factor value is a digital ping. ) stage or just before the negotiation (renegotiation) stage. It can also be measured periodically after the digital ping step.

[0479] As a result of the comparison, the current quality factor value (Q_current) is equal to or exceeds the quality factor threshold value (Q_thres hod), the wireless power transmitter 1920 determines that FO was not detected. The wireless power receiver 1910 can then transmit an ACK response (S1905 At this time, the state of the wireless power transmitter 1920 transitions from the negotiation stage to the power transmission stage. This can be done.

[0480] As a result of the comparison of the 1904 steps mentioned above, the current quality factor value (Q_current) is If the threshold value (Q_threshold) is less than the threshold value, the wireless power transmitter 1920 detects the FO. The wireless power receiver 1910 can then determine that the received signal has been received and transmit a NAK response to the wireless power receiver 1910 (S19 At this time, the state of the wireless power transmitter 1920 transitions from the negotiation phase to the selection phase. This can be done.

[0481] According to yet another embodiment of the present invention, a wireless power transmitter transmits FOD status information via a plurality of FOD status packets. It is also possible to obtain the reference quality factor value, the reference quality factor accuracy and the reference quality factor drop value. At this time, the wireless power transmitter can obtain a reference quality factor value, a reference quality factor accuracy, a reference quality factor The critical value of the quality factor may be determined using at least one of the child drop value, production and measurement error. can.

[0482] In one example, the wireless power transmitter may include a reference quality factor value, a reference quality factor accuracy, a reference quality factor The output value of a predetermined quality factor critical value generating function with the drop value as an input variable is determined as the quality factor critical value. It is also possible.

[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 child drop value can also be obtained from the wireless power receiver.

[0484] As an example, a wireless power transmitter may be designed to measure a quality factor based on a measured value 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 for explaining a method for detecting an FO based on a quality factor value according to an embodiment of the present invention. This is a low chart.

[0487] Referring to FIG. 20, the wireless power transmitter transmits a first frequency within a preset operating frequency band. A 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 and / or the applicable 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 is configured to receive a second power signal for a second frequency within the operating frequency band that is greater than the first frequency. The quality factor value can be measured (S2003).

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

[0490] In one embodiment, the first frequency is the operating frequency for the maximum quality factor value of 12 to 11 g (O perating frequency for peak Q Factor val For this reason, the S2005 stage is the FOD status during the negotiation stage. Receive the packet, check the first frequency, and check the first quality corresponding to the checked first frequency. The factor value can be compared with a second quality factor value corresponding to a second frequency greater than the first frequency. Cut.

[0491] In yet another embodiment, the first frequency may be 100 khz. The frequency agreed upon for this purpose is determined to be 100 kHz, and the reference quality factor value is measured and transmitted / received. So the first frequency may be 100 kHz.

[0492] If the first quality factor value is greater than the second quality factor value as a result of the comparison, the wireless power transmitter It can be determined that the power receiver is aligned and placed on the charging area (S2007). Here, the coupling coefficient between the transmitting resonant coil (primary coil) and the receiving resonant coil (secondary coil) is A high state can mean a well-ordered state.

[0493] If the second quality factor value is greater than the first quality factor value as a result of the comparison in step 2005, The power transmitter may be damaged if there are foreign objects on the charging area or if the wireless power receiver is not aligned. It can be determined that this has been done (S2009).

[0494] In another embodiment, the comparison result of step 2005 shows that the second quality factor value is greater than the first quality factor value. If the detection signal is large enough, it may simply indicate the presence of a foreign object in the charging area.

[0495] The second frequency is higher than the misaligned state in the presence of foreign matter. The quality factor value corresponding to the first frequency appears to be larger than the quality factor value corresponding to the second frequency. Foreign substances with small impact have similar quality factor values ​​to the unaligned ones. A quality factor that can be measured when foreign substances that have a relatively large effect are present. The child values ​​show a relatively large difference from the quality factor values ​​measured when unaligned receivers are present. can be expressed.

[0496] In one embodiment, the wireless power transmitter may be configured to receive a foreign object or a misaligned wireless power receiver. If it is determined that a foreign object or an aligned object has been detected, the power transmission will be stopped if power is currently being transmitted. and outputting a predetermined alarm signal to indicate that an unregistered wireless power receiver has been placed. This can be done.

[0497] After the wireless power transmitter outputs the alarm signal, it waits for a certain period of time before entering the selection stage. The receiver can also be searched for. Any foreign objects placed in the charging area can be removed by the user. How can a misaligned wireless power receiver be properly repositioned by the user? Taking the time into consideration, the waiting time before entering the selection step can be determined. .

[0498] According to another embodiment of the present invention, a wireless power transmitter is configured to select the first frequency before entering the selection step. The quality factor values ​​for the number and second frequency are measured and compared to determine whether a different It can be confirmed whether the foreign substance has been removed. If the removal of the foreign substance is confirmed, the wireless power The transmitter can enter a selection phase.

[0499] According to yet another embodiment of the present invention, the wireless power transmitter includes: The quality factor values ​​for the first and second frequencies are measured and compared to determine whether the wireless power receiver is If the wireless power receiver is aligned, the wireless The line power transmitter may also enter into the selection stage.

[0500] In the wireless power transmitter according to the embodiment, steps 2701 to 2709 are performed as shown in FIG. This can be accomplished in the selection step 210, but this is only one embodiment, and the negotiation step 24 0, such as the selection step 210, the ping step 220, and the identification and configuration step It may also be carried out in any one of the stages of 230.

[0501] In another embodiment of the present invention, the steps 2701 to 2709 are the same as those in FIG. This can also be performed in the power transmission step 260. In this case, the wireless power transmitter is While power control using the node is being performed, the quality factor value is measured for each frequency and compared to improve the quality. It can also determine whether foreign matter is present in the charged region.

[0502] According to yet another embodiment of the present invention, a wireless power transmitter is provided that transmits power within a preset operating frequency band. The quality factor peak frequency at which the maximum quality factor value is measured can be determined (or obtained). (S2001, S2003). A preset operating frequency band (or a specific frequency band) ) to find the operating frequency at which the maximum quality factor value is measured. The wireless power transmitter transmits the FOD status including the reference peak frequency from the wireless power receiver. s packets are received, and the reference peak frequency is compared with the obtained quality factor peak operating frequency. It is possible to determine whether or not a foreign substance is present. It is possible to directly compare the frequency with the reference peak frequency. The critical frequency is determined by taking into consideration the transmission coil or design, product error, etc., and the product obtained One can also compare the quality factor peak operating frequency 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. be.

[0504] Referring to FIG. 21, the FO detection device 2100 includes a first quality factor measurement unit 2110, a second quality factor measurement unit 2112, and a The device includes a quality factor measuring unit 2120, a detection unit 2130, an alarm unit 2140, and a control unit 2150. In yet another embodiment, the first quality factor measurement unit and the second quality factor measurement unit They can be integrated into one module or device. In this case, the same measuring unit The first and second quality factor values ​​are measured by adjusting the operating frequency of the control unit 2150. Alternatively, the same measurement unit can achieve the maximum quality factor value by adjusting the operating frequency of the control unit. and storing in memory the quality factor peak operating frequency corresponding to the corresponding maximum quality factor value. It is possible.

[0505] The first quality factor measurement unit 2110 measures a first frequency within a preset operating frequency band. A first quality factor value corresponding to the quality of the sample can be measured.

[0506] The second quality factor measurement unit 2120 measures a second frequency within a preset operating frequency band. A second quality factor value can be measured that corresponds to a second frequency, where the second frequency is greater than the first frequency. The frequency difference between the first frequency and the second frequency is determined based on the bandwidth of the operating frequency band. As an example, the first frequency and the second frequency can be, but are not limited to, The lower and upper frequency limits of the operating frequency band can then be determined.

[0507] The detection unit 2130 detects whether a foreign substance is present in the charging area based on the first quality factor value and the second quality factor value. Alternatively, it is possible to determine whether the quality factor peak operating frequency and wireless power reception A foreign object is present in the charging area based on the reference quality factor peak operating frequency received from the signal unit. It is possible to determine whether

[0508] For example, the detection unit 2130 may determine that the second quality factor value is greater than the first quality factor value. It is determined that a foreign object is placed on the power area or that an unaligned wireless power receiver is placed. On the other hand, the detection unit 2130 detects that the second quality factor value is smaller than the first quality factor value. If not, it can be determined that the aligned wireless power receiver is placed on the charging area.

[0509] As another example, the detection unit 2930 detects whether the second quality factor value is lower than the first quality factor value by a predetermined reference value. If it is larger than this, there may be foreign objects placed on the charging area or the wireless power receiver may be misaligned. On the other hand, the detection unit 2130 may determine that the first quality factor value is greater than or equal to the second quality factor value. The difference between the first and second quality factor values ​​is smaller than the specified reference value. If not, it can be determined that the aligned wireless power receiver is placed on the charging area.

[0510] As yet another example, the detector 2130 may be configured to detect quality factors due to frequency changes within the operating frequency band. Based on the rate of change in the charger value, the device detects the presence of foreign matter on the charging area or misaligned wireless devices. It may also be determined that a power receiver has been deployed.

[0511] Here, the change ratio is the value obtained by subtracting the first quality factor value from the second quality factor value. The quality factor may be calculated by dividing the value by, but is not limited to, the frequency change. Any mathematical formula that can calculate the rate of change of a value is sufficient.

[0512] The detection unit 2130 detects whether the calculated change ratio is greater than 0 or a predetermined positive number. If the threshold is exceeded, foreign objects may be placed on the charging area or the wireless power receiver may be misaligned. It can be determined that the position is placed.

[0513] On the other hand, the detection unit 2130 detects that the calculated change ratio is smaller than 0 or is a predetermined negative number. If the second threshold is not exceeded, it is determined that the wireless power receivers are aligned on the charging area. It is possible.

[0514] The detector 2130 detects a foreign object or a misaligned wireless power receiver. The output result can be transmitted to the control unit 2150.

[0515] The alarm unit 2140 detects the presence of a foreign substance on the charging area under the control of the control unit 2150. or a predetermined alarm signal to indicate the presence of an unaligned wireless power receiver. The alarm can be output via the alarm means provided. Here, the alarm means is a buzzer ( These may include buzzers, LED lights, vibrations, and LCD displays. Not limited to:

[0516] According to an embodiment, the control unit 2150 may be configured to receive a foreign object or a misaligned wireless power receiver. If it is determined that the power has been transmitted, the power transmission is interrupted if the power transmission is currently in progress. The power transmission unit 2160 is controlled so that a foreign object or a misaligned wireless power receiver is placed. The alarm unit 2140 is controlled so that a predetermined alarm signal is output to indicate that the It is possible.

[0517] After the control unit 2150 outputs the alarm signal, it waits for a certain period of time before entering the selection stage. The receiver can also be searched for.

[0518] Foreign objects placed in the charging area may be removed by the user or misaligned wireless devices may be damaged. The selection step takes into account the time it takes for the force receiver to be properly repositioned by the user. A time to wait before entering the can be determined.

[0519] According to another embodiment of the present invention, the control unit 2150 may select the first frequency before entering the selection step. the first and second quality factor measuring units for measuring a quality factor value for a number and a second frequency. 2110, 2120, and comparing the measured first and second quality factor values ​​to determine the charging area. It is also possible to check whether the foreign object placed in the container has been removed. If so, the control unit 2150 may enter a selection step.

[0520] According to another embodiment of the present invention, the control unit 2150 may include a A control is performed to measure quality factor values ​​for the first frequency and the second frequency, and the measured first and second frequencies are Based on the second quality factor value, it can be confirmed whether the wireless power receiver is aligned properly. If the wireless power receivers are properly aligned, the controller 2150 proceeds to a selection step. You can also enter.

[0521] In yet another embodiment, the foreign substance detection step is performed in a selection step, i.e., before the ping step. In this case, if a foreign object is detected in the selection step, the wireless power transmitter It is possible to maintain the selection stage without entering the ping stage.

[0522] According to another embodiment of the present invention, the control unit 2150 may That is, if a foreign object is detected in the power transmission step 260 of FIG. 2, the power transmission is temporarily stopped. and outputting a predetermined alarm signal indicating that a foreign substance has been sensed. When it is confirmed that the foreign object detected during the alarm signal output has been removed from the charging area Then, the control unit 2150 can perform control so that power transmission resumes.

[0523] FIG. 22 is a flow chart for explaining a method for detecting an FO based on a quality factor value in another embodiment of the present invention. -Chart.

[0524] Referring to FIG. 22, the wireless power transmitter transmits a predetermined operating frequency band at a certain frequency. The frequency band can be divided into a first frequency band to an Nth frequency band having a certain interval (S2201). The operating frequency band is broadly divided into a lower frequency band, a middle frequency band, and an upper frequency band. Here, the size of each frequency band can be changed according to the user's settings. As an example, if the operating frequency band is 10 0KHz to 210KHz, and is used to distinguish specific frequencies within the operating frequency band. If the frequency interval for the 10KHz band is set, the corresponding operating frequency band is 1st to 12th frequencies. Here, the first to third frequencies are the lower limit frequency band (100KH z~130KHz, 4th to 9th frequencies are in the intermediate frequency band (130KHz~180KHz ), and the 10th to 12th frequencies are classified as the upper limit frequency band (180KHz to 210KHz). This is merely an example, and the setting and configuration of the wireless power transmitter may be performed. and / or) different operating frequency bands and frequency intervals are set by the applicable standards. You have to be careful that you can.

[0525] The wireless power transmitter is configured to transmit the power from the N-K+1th frequency to the Nth frequency in the upper frequency band. The average value (a1) of the measured quality factor values ​​(etc.) can be calculated (S2203). .

[0526] In addition, the wireless power transmitter transmits the first frequency to the Nth frequency included in the upper limit frequency band. An average value (a2) of the measured quality factor values ​​(etc.) can be calculated (S2205).

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

[0528] As a result of the comparison, the average quality factor (a2) for the lower frequency band was If the quality factor value is greater than the average value (a1), the wireless power transmitter is aligned with the wireless It can be determined that the line power receiver is installed (S2209). The coupling coefficient between the coil (primary coil) and the receiving resonant coil (secondary coil) is high and well aligned. It can mean the state of being.

[0529] As a result of the comparison of the 2207 steps mentioned above, if a2 is equal to or smaller than a1, the wireless power The transmitter will determine that a foreign object or an unaligned wireless power receiver has been placed on the charging area. (S2211).

[0530] The wireless power transmitter must not be placed on the charging area with foreign objects or misaligned wireless power receivers. A predetermined alarm signal can be output to indicate that the operation has been completed (S2213).

[0531] In the wireless power transmitter according to an embodiment, steps 2201 to 2213 are performed as shown in FIG. This can be accomplished in the selection step 210, but this is only one embodiment, and the negotiation step 24 0, such as the selection step 210, the ping step 220, and the identification and configuration step It may also be carried out in any one of the stages of 230.

[0532] In another embodiment of the present invention, the steps 2201 to 2213 are the same as those in FIG. This can also be accomplished in the power transmission step 260. In this case, the wireless power transmitter operates at While performing power control by adjustment, the quality factor value can be measured for each frequency. The wireless power transmitter determines the quality factor of the upper frequency band by using the measured quality factor value for each frequency. The average quality factor of the lower frequency band is calculated, and then the average quality factor of the lower frequency band is compared to determine whether there are any differences in the charging area. It can also determine whether a substance is present.

[0533] In the embodiment of FIG. 21, the average quality factor (a1) of the upper frequency band and the average quality factor (a2) of the lower frequency band are simply The average value of the quality factor (a2) of the band is compared to determine whether or not a foreign substance is present. However, this is merely one embodiment, and wireless power transmission according to other embodiments of the present invention may be performed. The machine not only checks whether the average quality factor increases or decreases with frequency change, but also checks the average quality factor Depending on the increase / decrease, foreign objects or misaligned wireless power receivers may be in the charging area. For example, if a2 minus a1 is a negative value, If the absolute value of the difference between a2 and a1 exceeds a predetermined threshold value, the wireless power transmitter determines that a foreign object or an unaligned wireless power receiver has been placed on the charging area. can be done.

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

[0535] Referring to FIG. 23, an FO detection device 2300 includes an operating frequency division unit 2310, a quality factor A measuring 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 into predetermined frequency intervals. Then, the quality factor value is divided into 1st to Nth frequencies to be measured, and the divided frequencies are set as the lower limit frequency. The lower limit frequency band can be divided into a lower frequency band, a middle frequency band, and an upper limit frequency band. The number of frequencies to be measured included in the band and the lower limit frequency band is predefined and a predetermined recording area is The operating frequency band, frequency interval, lower / upper frequency band, The number of measurement target frequencies included in the wireless power transmitter is determined by the user interface. and (a) an external device that is connected to the wireless power transmitter via a wired or wireless communication network. Be aware that this can be changed by the server.

[0537] The quality factor measurement unit 2320 can measure quality factor values ​​corresponding to the first to Nth frequencies. According to an embodiment, the quality factor measurement unit 2340 may include a lower limit frequency band and an upper limit frequency band. It is also possible to measure only the quality factor values ​​for the selected target frequencies.

[0538] The average calculation unit 2330 calculates the average value ( a2) and the average value (a1) of the quality factor values ​​(etc.) measured for the upper frequency band. It is possible.

[0539] The detection unit 2340 detects the foreign matter or aligned objects arranged on the charging area based on a1 and a2. and transmits the detection result to the control unit 2360. As an example, the detection unit 2340 detects that a value obtained by subtracting a2 from a1 is a positive number, i.e. If the average quality factor value increases as the frequency in the operating frequency band increases, It can be determined that there is a foreign object or an unaligned wireless power receiver in the If the value obtained by subtracting a2 from a1 is negative, that is, if the operating frequency band If the average quality factor value decreases as the frequency in the region increases, It can be determined that a wireless power receiver is present.

[0540] As another example, the detector 2340 may detect a quality factor average according to a change in frequency within the operating frequency band. Consider not only the increase or decrease in the value but also the increase / decrease in the average quality factor. It can also determine if a foreign object or an unaligned wireless power receiver has been placed in the charging area. For example, if the value obtained by subtracting a1 from a2 is a negative number, the difference between a2 and a1 is If the absolute value of exceeds a certain critical value, the wireless power transmitter is It can be determined that the line power receiver has been placed over the charging area.

[0541] The alarm unit 2350 detects the presence of a foreign substance on the charging area under the control of the control unit 2360. or a predetermined alarm signal to indicate the presence of an unaligned wireless power receiver. The alarm can be output via an alarm means provided in the device. Here, the alarm means is a buzzer. It can include buzzers, LED lights, vibrations, LCD displays, etc. This is not limited to the above.

[0542] 24a to 24d are experimental diagrams for explaining the logical basis of the embodiments of FIGS. 20 to 23. 1 is a graph showing the test results.

[0543] Referring to reference numeral 2411 in FIG. 24a, only the first receiver is disposed on the charging area. In this case, the quality factor value measured by the wireless power transmitter is within the operating frequency band (100KHz~210 As the frequency (in KHz) increases, the frequency decreases. In reference, when the first receiver and the foreign object FO4 are placed on the charging area, wireless power The quality factor value measured at the transmitter increases with increasing frequency within the operating frequency band. This indicates that.

[0544] Referring to the reference numeral 2413, when only the first receiver is placed in the charging area, the operating period is The quality factor value measured at a frequency of 100KHz is 44, while that measured at an operating frequency of 210KHz The quality factor value is 40. On the other hand, the first receiver and the foreign object are in the charging area. When FO4 was placed, the quality factor value measured at an operating frequency of 100 KHz was 27.1. It was found that the quality factor value measured at an operating frequency of 210KHz was 30.65. Here, FO4 means standard foreign matter as defined in the WPC standard.

[0545] The experimental results shown in FIG. 24a were obtained when the wireless power receivers were aligned in the charging area. When the frequency is increased within the operating frequency band, the quality factor value decreases. When foreign matter is placed in the region, the quality factor Indicates that the value is increasing.

[0546] FIG. 24b is for a second receiver made by a different manufacturer than the first receiver of FIG. 24a. These are the experimental results.

[0547] Referring to reference numeral 2421 in FIG. 24b, only the second receiver is disposed on the charging area. In this case, the quality factor value measured by the wireless power transmitter is within the operating frequency band (100KHz~210 It shows that the quality factor value decreases as the frequency (in KHz) increases. In reference to No. 2422, when a second receiver and a foreign substance, FO4, are placed on the charging area, In this case, the quality factor value measured for a wireless power transmitter decreases as the frequency increases within the operating frequency band. This indicates that it increases.

[0548] In fact, referring to reference numeral 2423, when only the second receiver is placed in the charging area, The quality factor value measured at an operating frequency of 100 KHz was 39.5, and at an operating frequency of 210 The quality factor value measured in KHz is found to be 31.1. When the transmitter and the foreign substance FO4 are placed, the quality is measured at an operating frequency of 100KHz. The quality factor value measured at an operating frequency of 210KHz was 26.1. I realize something.

[0549] The experimental results shown in FIG. 24b, like those in FIG. 24a, show that the charging area When wireless power receivers are aligned and placed in a row, as the frequency within the operating frequency band increases, However, if a foreign object is placed in the charging area, the quality factor value decreases. It is shown that the quality factor value increases as the frequency increases.

[0550] Figure 24c shows the results of the standard definition of foreign material FO4 and a dime in the operating frequency band. The quality factor values ​​measured for each are shown.

[0551] The reference numbers 2431 and 2432 in Fig. 24c are measured for a 10-cent copper coin and FO4, respectively. The change pattern of the quality factor value determined by the measurement is shown in FIG. If a foreign object other than a wireless power receiver is placed in the charging area, the frequency within the operating frequency band It can be seen that the quality factor value increases as increases.

[0552] However, in the case of 10-cent copper coins, some quality factor values ​​measured in the intermediate frequency band are higher than the upper frequency band. This indicates that the quality factor value measured in several bands is greater than the actual value. In order to minimize the occurrence of erroneous judgment, as described above in FIG. 22 and FIG. 23, The quality factor average values ​​calculated for the lower and upper frequency bands are Based on this, it is possible to determine whether or not a foreign substance is present.

[0553] FIG. 24d shows a third receiver sold by a different manufacturer than the first and second receivers described above. The experimental results are shown below.

[0554] Referring to reference numeral 2441 in FIG. 24d, when only the third receiver is placed in the charging area, In this case, the quality factor value decreases with increasing frequency, but as shown in FIG. If a foreign object, such as FO4 or a 10-cent copper coin, is placed in the charging area, It is shown that the quality factor value increases with increasing wavenumber.

[0555] Figure 24e shows the standard wireless power transmitter and standard wireless power receiver module used for product authentication. The experimental results are presented.

[0556] Referring to reference numeral 2452 in FIG. 24e, a standard wireless power transmitter is provided with a standard wireless power receiving module. When the modules are placed in the operating frequency band, the quality factor value increases with increasing frequency. Of course, as shown by reference numeral 2451, standard wireless power transmission Even if nothing is placed in the charging area of ​​the device, the frequencies within the operating frequency band increase. Therefore, it can be seen that the quality factor value is reduced. However, referring to the reference number 2453, the standard Measured with a standard wireless power receiver module placed in the charging area of ​​the wireless power transmitter. The quality factor value is generally smaller by a certain level than when nothing is placed in the charging area. You can see that it will become

[0557] Figure 25 shows the quality factor value according to the placement of a wireless power receiver and foreign objects in the charging area of ​​a wireless power transmitter. 13 is a diagram for explaining the relationship between the maximum quality factor peak frequency and the maximum quality factor peak frequency.

[0558] The table shown in Fig. 25 shows the results when only the wireless power receiver is placed in the charging area and when the What is the maximum quality factor peak frequency when a transmitter and a foreign object are placed together in the charging area? In this case, the maximum quality factor peak frequency is used to determine whether the particle is shifted. It is possible to determine whether quality exists or not.

[0559] The wireless power transmitter receives information about the reference quality factor peak frequency from the wireless power receiver. The critical frequency can be determined based on the received information. The number can be determined by taking into consideration the coil design, circuit characteristics, tolerances, etc. By comparing the frequency with the peak frequency in Figure 25, the wireless power transmitter can determine the presence of foreign matter. It is possible to determine nothing.

[0560] FIG. 26 illustrates a state transition process for detecting foreign matter in a foreign matter detection device according to an embodiment of the present invention. FIG.

[0561] Referring to FIG. 26, if an object is detected in a selection step 2610, the foreign substance detection device selects a plurality of The quality factor value of the resonant circuit for the operating frequency can be measured (S2601). Here, the number of operating frequencies for which the quality factor value is measured may be 2 to 6, but is not limited thereto. The operating frequency value at which the quality factor value is measured is a predetermined value. These are values ​​selected within a defined operating frequency range for As an example, the operating frequency range of the foreign matter detection device may be selected as 100 KHz. If the number of operating frequencies measured is 5, the quality factor value is The operating frequency values ​​set are 100KHz, 130KHz, 160KHz, 190KHz and It can be 220KHz.

[0562] The foreign object detection device determines whether a foreign object has been placed in the charging area based on the measured quality factor value. That is, it is possible to determine whether or not a foreign substance is present (S2602).

[0563] As an example, a foreign material detection device may exhibit an increase in quality factor value as the operating frequency increases. If the foreign object is detected, it can be determined that a foreign object is present in the charging area. If the quality factor value decreases as the operating frequency increases, there is no foreign material in the charging area. It is possible to make a judgment.

[0564] In another example, the foreign substance detection device may calculate a change in quality factor value for adjacent operating frequencies. The average of the calculated changes is set to a predetermined reference value (for example, the reference value may be 0, but is not limited thereto). If the measured value exceeds the threshold (not specified), it can be determined that a foreign substance is present in the charging area. The adjacent operating frequencies are the two operating frequencies that are closest to each other among the operating frequencies at which the quality factor value is measured. It means frequency.

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

[0566] When the foreign substance detection device has completed the determination of the presence or absence of a foreign substance, the device proceeds to a ping step 2620. Can enter.

[0567] In the ping step 2620, the foreign object detection device pings the wireless power receiver with a predetermined electrical potential to identify the wireless power receiver. A force signal, for example a digital ping, may be transmitted periodically.

[0568] If a signal strength indicator is received in the ping step 2620, the foreign object detection device performs an identification and configuration The wireless power receiver is identified in step 2630, and a Various configuration parameters can be set.

[0569] Once the identification and configuration of the wireless power receiver is completed, the foreign object detection device proceeds to negotiation step 264. 0 and sends a foreign object detection status packet (FOD Stat) from the identified wireless power receiver. us Packet) can be received (S2603). The packet may include a reference quality factor value.

[0570] The foreign matter detection device detects the wireless power receiver identified based on the result of the judgment in step 2602. The receiver can then transmit a NAK response signal or an ACK response signal to the receiver (S2604). At that time, the foreign substance detection device determines whether or not a foreign substance is present based on the received foreign substance detection status packet. In the judgment of step 2602, the threshold value (or threshold range) for judging the threshold value may not be determined. If the result of the test indicates that a foreign object is present, the foreign object detection device sends a NAK response signal to the After transmitting the signal to the receiver, the process proceeds to a selection step 2610. The power output device will interrupt power transmission and issue a predefined warning alarm indicating that a foreign object has been detected. It can be output.

[0571] For example, if it is determined in step 2602 that no foreign matter is present, the foreign matter detection device After transmitting the ACK response signal, the device may transition to the power transmission stage 2650. For example, if the foreign matter is not present as a result of the determination in step 2602, the foreign matter detection device It is also possible to transition to the power transfer stage 2650 via the compensation stage 250 of FIG.

[0572] The foreign substance detection device enters the power transmission step 2650 and transmits wireless power to the corresponding wireless power receiver. Charging can begin.

[0573] The foreign substance detection device that has transitioned to the selection step 2610 due to the detection of a foreign substance periodically performs a plurality of movements. The quality factor value of the resonant circuit for the operating frequency is measured, and a foreign object is detected based on the measured quality factor value. If the result of the judgment is that the foreign matter has been removed, The detection device enters the power transmission step 2650 and resumes power transmission to the corresponding wireless power receiver. On the other hand, after the transition to the selection step 2610 due to the detection of a foreign substance, If the detected foreign matter is not removed during the period, the foreign matter detection device A predetermined warning alarm can be output to indicate that the information has not been removed.

[0574] According to another embodiment of the present invention, the foreign matter detection device corresponds to the determination result of the step 2601. Prescribed foreign material presence information including foreign material status information (FO Status Information) Presence Status Packet is sent to the corresponding wireless For example, if the foreign object status information is '0', '1' means that no foreign object was detected, and '2' means that a foreign object was detected. It can be, but is not limited to,

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

[0576] FIG. 27 is a block diagram illustrating a message structure of an FOD status packet according to another embodiment of the present invention. This is a diagram of the

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

[0578] As shown by reference numeral 2704, the mode 2702 field is set to binary '00'. If so, all bits in the first data 2701 field are recorded as 0, and the reference quality factor value It is determined by measuring the wireless power receiver in the 2703 field with the power turned off. The reference quality factor value obtained is recorded. Meanwhile, if the mode 2702 field is set to binary '01', If set, the first data 2701 field indicates that the power supply of the corresponding wireless power receiver is turned off. The operating frequency at which the quality factor value measured in the state where the temperature was 5% lower than the reference quality factor value was recorded. The reference quality factor value 2703 field indicates that the power supply of the wireless power receiver is O The reference quality factor value measured and determined in the FF state may be recorded. Referring to FIG. 20, the reference quality factor value of the receiver 2 is Hz, which is 39.5, which is 5% lower than the reference quality factor value. The quality factor value is 37.525. Therefore, the quality factor is 5% lower than the reference quality factor value. The operating frequency with the child value can be anywhere between 120KHz and 130KHz.

[0579] In the embodiment of FIG. 27 described above, the operation having a quality factor value 5% lower than the reference quality factor value is It is assumed that a value corresponding to a frequency is recorded in the first data 2701 field. However, this is merely an example, and other values ​​other than 5%, such as 7%, may be used by those skilled in the art. Can also be set to %.

[0580] FIG. 28 illustrates a state transition process for detecting foreign matter in a foreign matter detection device according to an embodiment of the present invention. FIG.

[0581] Referring to FIG. 28, the foreign object detection device selects an object if an object is detected in step 2810. Measure the quality factor value of the resonant circuit for multiple operating frequencies, including the lower limit of the operating frequency band. Here, the number of operating frequencies at which the quality factor value is measured is The number may be 2 to 8, but is not limited thereto, and may be more than this. The operating frequency at which the factor value is measured is a value selected within a predefined operating frequency range. The frequency may be selected to have a certain frequency interval, but is not limited to this. As an example, the operating frequency of the foreign substance detection device may be selected from the operating frequency range. The frequency range can be from 100KHz to 220KHz. In this case, the lower limit frequency is 100K. Hz and the number of operating frequencies to be measured is 7. The frequency values ​​are 100KHz, 120KHz, 140KHz, 160KHz, 180KHz, It can be 200KHz and 220KHz.

[0582] The foreign matter detection device records the quality factor values ​​measured for each operating frequency in a predetermined recording area. This can be done.

[0583] When the measurement of the quality factor value is completed, the foreign substance detection device proceeds to a ping step 2820. This can be done.

[0584] In a ping step 2820, the foreign object detection device pings a predetermined power source for identifying the wireless power receiver. A force signal, for example a digital ping, may be transmitted periodically.

[0585] If a signal strength indicator is received in ping step 2820, the foreign object detection device performs an identification and configuration The wireless power receiver is identified in step 2830, and a Various configuration parameters can be set.

[0586] Once the identification and configuration of the wireless power receiver is complete, the foreign object detection device proceeds to negotiation step 284. 0 and sends a foreign object detection status packet (FOD Stat) from the identified wireless power receiver. us Packet) can be received (S2802). The packets are assigned with operating frequencies having a quality factor value that is 5% lower than the reference quality factor value (hereinafter, For ease of explanation, information about the critical frequencies (referred to as 'critical frequencies') may be included.

[0587] The foreign material detection device is a quality factor corresponding to the lower limit frequency measured in the aforementioned 2801 step. The quality factor value (Q1) is compared with the quality factor value (Q2) measured at an operating frequency greater than the critical frequency. Here, Q2 is the frequency that is higher than the critical frequency. The quality factor value having the maximum value among the quality factor values ​​measured at the operating frequency greater than .

[0588] If Q2 is greater than Q1, the foreign object detection device detects that a foreign object has been placed in the charging area. On the other hand, if Q2 is smaller than Q1, the foreign object detection device is in the charging area. It can be determined that no foreign substance is present.

[0589] In another embodiment, the quality factor of the foreign matter detection device is measured by 2801 steps. Based on the value, the quality factor value corresponding to the critical frequency can be determined (or estimated). For example, the critical frequency of the multiple operating frequencies used to measure the quality factor value in step 2801 is When the same frequency as the wave number is included, the quality factor value measured at the corresponding operating frequency is the critical frequency. However, the quality factor value measured in step 2801 is If the multiple operating frequencies do not include the same frequency as the critical frequency, at least one quality factor value measured at the closest operating frequency to the critical frequency The corresponding quality factor value can also be estimated. A linear function is derived using the quality factor values ​​measured at the two operating frequencies, and the derived linear function The quality factor value corresponding to the critical frequency can be estimated by substituting the critical frequency into the number. This is not limited to the above.

[0590] The foreign matter detection device detects the wireless power receiver identified based on the result of the judgment in step 2803. The receiver can then transmit a NAK response signal or an ACK response signal to the receiver (S2804). At that time, the foreign substance detection device determines whether or not a foreign substance is present based on the received foreign substance detection status packet. In the judgment of step 2803, the threshold value (or threshold range) may not be determined. If the result of the test indicates that a foreign object is present, the foreign object detection device sends a NAK response signal to the After transmitting the signal to the receiver, the process proceeds to a selection step 2810. The power output device will interrupt power transmission and issue a predefined warning alarm indicating that a foreign object has been detected. It can be output.

[0591] For example, if it is determined in step 2802 that no foreign matter is present, the foreign matter detection device After transmitting the ACK response signal, the device may transition to the power transmission stage 2850. For example, if the foreign matter is not present as a result of the determination in step 2803, the foreign matter detection device It is also possible to transition to the power transfer stage 2850 via the compensation stage 250 of FIG.

[0592] The foreign matter detection device enters into a power transmission step 2850 to wirelessly charge the corresponding wireless power receiver. The electricity can be started.

[0593] The foreign substance detection device that has transitioned to the selection step 2810 due to the detection of a foreign substance periodically performs a plurality of movements. The quality factor value of the resonant circuit for the operating frequency is measured, and a foreign object is detected based on the measured quality factor value. If the result of the judgment is that the foreign matter has been removed, The detection device enters the power transmission step 2850 and resumes power transmission to the corresponding wireless power receiver. Meanwhile, after transitioning to the selection step 2810 due to the detection of a foreign substance, If the foreign matter detected by the foreign matter detection device is not removed, the foreign matter detection device A predetermined warning alarm may be output to indicate that the measurement has not been performed.

[0594] According to another embodiment of the present invention, the foreign matter detection device corresponds to the determination result of the step 2801. Prescribed foreign material presence information including foreign material status information (FO Status Information) Presence Status Packet is sent to the corresponding wireless For example, if the foreign object status information is '0', '1' means that no foreign object was detected, and '2' means that a foreign object was detected. It can be, but is not limited to,

[0595] FIG. 29 illustrates a state transition process for detecting foreign matter in a foreign matter detection device according to an embodiment of the present invention. FIG.

[0596] In the present embodiment, if an object is detected in the selection step 2910, the foreign object detection device selects a plurality of moving objects. The quality factor value of the resonant circuit versus operating frequency can be measured (S2901).

[0597] The foreign object detection device receives an FOD status packet containing a critical frequency during the negotiation phase. For example, at least two operating frequencies equal to or greater than the critical frequency are identified. A quality factor value measured at the selected operating frequency may be extracted (S2903).

[0598] The foreign substance detection device is provided with a frequency band that corresponds to each of the operating frequencies equal to or greater than the critical frequency. The presence or absence of foreign matter can be determined by comparing the quality factor values ​​of the samples (S2904). As a result, if the quality factor value increases as the operating frequency increases, the foreign material detection device is On the other hand, as the operating frequency increases, If the quality factor value decreases, the foreign matter detection device determines that no foreign matter is present in the charging area. It is possible.

[0599] According to another embodiment of the present invention, when an object is detected in the selection step, the foreign substance detection device: It is also possible to scan the quality factor values ​​within the operating frequency band.

[0600] Here, the operating frequency band may be divided into a number of non-overlapping sub-frequency ranges. In one example, the operating frequency band may include a first frequency range including a lower frequency limit and an upper frequency limit. The second frequency region may include:

[0601] For example, if the operating frequency band is 100KHz to 200KHz, the first frequency region is The second frequency range is 100KHz to 150KHz, including the lower limit of 100KHz. The limit frequency may be 151KHz to 200KHz, including 200KHz.

[0602] The foreign substance detection device changes the frequency in the first frequency range in fixed frequency increments to check the quality. Scan the factor values ​​and identify the operating frequency (first frequency) at which the highest quality factor value is measured. The foreign substance detection device can also detect the product while changing the frequency in the second frequency range. Scan the quality factor values ​​and identify the operating frequency (second frequency) at which the highest quality factor value is measured The foreign substance detection device can obtain a quality factor value (Q4) corresponding to the first frequency and a quality factor value (Q5) corresponding to the second frequency. Compare the quality factor value (Q5) corresponding to the frequency to determine whether foreign matter is present in the charging area For example, if Q5 is greater than Q4, the foreign substance detection device can determine that a foreign substance is present. On the other hand, if Q5 is smaller than Q4, the foreign substance detection device It can be determined that no foreign matter is present.

[0603] FIG. 30 illustrates a message structure of an FOD status packet according to yet another embodiment of the present invention. This is a diagram for explaining the method.

[0604] Referring to FIG. 30, the FOD status packet message 3000 has a length of 2 bytes. A 6-bit long reserved 3001 field and a 2-bit long mode (Mod e) 3002 field, the first data 3003 field and the second data field 30 In the embodiment of FIG. 30 described above, the first data 3003 field The size of the field of the second data 3004 is 3 bits, and the size of the field of the second data 3005 is 5 bits. However, this is by way of example only and is not intended to be limiting. All bits in the approximately 3001 field are recorded as 0.

[0605] As shown by reference numeral 3005, the mode 3002 field is set to binary '00'. If so, the first data 3003 field and the second data 3004 field contain the corresponding wireless The reference quality factor value determined by measuring with the power receiver turned off is recorded. On the other hand, if the mode 3002 field is set to binary '01', the first data 30 The 03 field contains critical frequency information, and the second data 3004 field contains lower limit frequency information. The ratio information of the quality factor value corresponding to the critical frequency to the corresponding quality factor value is recorded respectively. It can be done.

[0606] The method according to the above-mentioned embodiment is implemented as a program for execution by a computer. The present invention can be stored in a computer-readable recording medium. Examples of the computer-readable recording medium include These include ROM, RAM, CD-ROM, magnetic tape, floppy disk, and optical data. storage devices, and also carrier waves (e.g., transmission over the Internet) ) is also included.

[0607] The computer-readable recording medium is a computer system connected via a network. and the computer readable code can be stored and executed in a distributed manner. And a functional program for implementing the above-mentioned method, The code and the code segments are easily instructed by a programmer skilled in the art to which the embodiments pertain. It is arguable.

[0608] The present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It will be apparent to one skilled in the art that such a method can be used.

[0609] Therefore, the above detailed description should not be construed as limiting in all respects but as illustrative and The scope of the present invention is determined by the reasonable interpretation of the appended claims. The present invention includes all modifications within the scope of the present invention. do. [Industrial Applicability]

[0610] The method for detecting a foreign substance according to the embodiment uses the quality factor value to perform the following steps before the ping step, during the negotiation step, and after the ping step. A wireless charging device that detects foreign objects between wireless power transmitters during power transmission The present invention is applicable to power systems.

Claims

1. A power receiving method for a wireless power receiver, comprising: A packet transmission step of transmitting a plurality of packets including the FOD status packet to a wireless power transmitter; and receiving a response signal from the wireless power transmitter, the response signal indicating whether a foreign object is present in a charging area of ​​the wireless power transmitter; 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 included in the FOD status packet received from the wireless power receiver, The plurality of packets further include 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; The FOD status packet includes a 2-bit mode field and a 1-byte data value. The data value of the FOD status packet is determined by the value of the mode field.

2. each of the plurality of packets includes a preamble, a header, a message, and a checksum for identifying whether an error has occurred in each packet; The power receiving method of claim 1 , wherein the size of the message included in each packet is identified based on a value of the header.

3. The power receiving method according to claim 2 , wherein the header is for identifying a type of each of the packets.

4. The method of claim 1 , further comprising the step of modulating the plurality of packets prior to the packet transmitting step.

5. The method of claim 1 or 3, further comprising the step of measuring a strength of a power signal received from the wireless power transmitter.

6. The method of claim 1 , wherein the reference peak frequency is pre-assigned.

7. The FOD status packet has a length of 2 bytes, The power receiving method according to claim 1 , wherein 6 bits of one byte of the FOD status packet are a reserved field.

8. 2. The power receiving method of claim 1, wherein the response signal is determined by comparing a measured peak frequency of the 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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