Foreign substance detection method, device and system therefor

Abstract

A method for detecting foreign substances, which has the advantage of being able to detect foreign substances more effectively and accurately, and an apparatus and system for the method are provided. A wireless power transmitter (600) as a foreign substance detection device having a resonant circuit (630) for wirelessly transmitting power includes a sensing unit (670) that detects an object placed in a charging area, and a control unit (680) that measures a quality factor value of the resonant circuit when the object is detected, transmits a detection signal to identify the wireless power receiver, determines a threshold value for detecting the foreign substance based on a reference quality factor value received from the identified wireless power receiver, and compares the measured quality factor value with the determined threshold value to determine whether the foreign substance is present. The threshold value is determined by applying a weight that increases depending on the reference quality factor value.

Description

[Technical Field]

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

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

[0003] In order to connect information and communication devices anytime and anywhere, sensors equipped with computer chips with communication functions must be installed in all social facilities. Therefore, the power supply for these devices or sensors has become a new issue. Furthermore, with the rapid increase in the number of portable devices, including not only mobile phones but also Bluetooth handsets and music players like iPods, the task of charging batteries has become time-consuming and labor-intensive for users. Wireless power transmission technology has recently been attracting attention as a way to solve this problem.

[0004] Wireless power transmission (or wireless energy transfer) is a technology that transmits electrical energy wirelessly from a transmitter to a receiver using the principle of magnetic field induction. Electric motors and transformers that use the principle of electromagnetic induction were first used in the 1800s. Later, attempts were made to transmit electrical energy by emitting electromagnetic waves such as high frequency, microwaves, and lasers. The electric toothbrushes and some wireless razors that we commonly use are actually charged using the principle of electromagnetic induction.

[0005] Currently, wireless energy transmission methods can be broadly classified into magnetic induction methods, electromagnetic resonance methods, and RF transmission methods using short wavelength radio frequencies.

[0006] The magnetic induction method is a technology that uses the phenomenon whereby when two coils are placed next to each other and a current is passed through one coil, the magnetic flux generated at this time induces an electromotive force in the other coil, and has been quickly commercialized, primarily for small devices such as mobile phones. The magnetic induction method can transmit up to several hundred kilowatts of power and is highly efficient, but has the disadvantage that the maximum transmission distance is less than one centimeter, so it generally has to be placed next to the charger or underneath.

[0007] The magnetic resonance method is characterized by using electric or magnetic fields instead of electromagnetic waves or currents. The magnetic resonance method has the advantage of being almost unaffected by electromagnetic waves, making it safe for other electronic devices and the human body. However, it has the disadvantage of being only usable within limited distances and spaces, and having a relatively low energy transmission efficiency.

[0008] Short wavelength wireless power transmission, or simply RF transmission, takes advantage of the fact that energy can be transmitted and received directly in the form of radio waves. This technology is an RF-based wireless power transmission method that uses a rectenna. Rectenna is a combination of the words antenna and rectifier, and refers to an element that directly converts RF power into DC power. In other words, the RF method is a technology that converts AC radio waves into DC and is being actively researched for commercialization as its efficiency has improved recently.

[0009] Wireless power transmission technology can be used in a variety of ways not only in the mobile industry but also in industries across the board, including IT, railways, and home appliances.

[0010] If a conductor other than a wireless power receiver, i.e., a foreign object (FO), is present in the wireless charging area, the electromagnetic signal transmitted from the wireless power transmitter may be induced in the FO, causing the temperature to rise. Examples of FOs include copper coins, paperclips, pins, and ballpoint pens.

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

[0012] Therefore, accurately detecting the FO located in the charging area has become an important issue in the field of wireless charging technology. 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 an object of the present invention is to provide a method for detecting foreign matter for wireless charging, and an apparatus and system therefor.

[0014] Another object of the present invention is to provide a wireless power transmission device that can detect foreign matter more accurately by dynamically determining a critical value or critical range for detecting foreign matter by reflecting a weighted value determined linearly or exponentially according to a reference quality factor value.

[0015] Another object of the present invention is to provide a wireless power transmission apparatus capable of detecting foreign matter based on the quality factor value and inductance value of a resonant circuit measured before a ping step.

[0016] It is yet another object of the present invention to provide a foreign substance detection method and apparatus and system therefor that can more accurately detect foreign substances by measuring not only the quality factor value of the resonant circuit but also the inductance value before the ping step if an object is detected in the charging area, and comparing the measured value with a threshold value determined based on the FOD status packet in the negotiation step.It is another object of the present invention to provide a wireless power transmitter that can detect foreign substances based on a quality factor value measured corresponding to a specific frequency within the operating frequency band.

[0017] Another object of the present invention is to provide a wireless power transmitter capable of detecting foreign matter based on an average quality factor measured corresponding to a specific frequency within an operating frequency band.

[0018] The technical problems to be solved by the present invention are not limited to those mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the following description. [Means for solving the problem]

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

[0020] According to one embodiment of the present invention, a method for detecting a foreign substance in a wireless power transmitter having a resonant circuit for wirelessly transmitting power includes the steps of: detecting an object placed in a charging area; if the object is detected, measuring a quality factor value of the resonant circuit; identifying the wireless power receiver by transmitting a detection signal; determining a threshold value for detecting a foreign substance based on a reference quality factor value received from the identified wireless power receiver; and determining whether or not a foreign substance is present by comparing the measured quality factor value with the determined threshold value, wherein the threshold value can be determined by applying a weight that increases depending on the reference quality factor value.

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

[0022] In addition, a component factor corresponding to the wireless power transmitter and a predefined tolerance may be further applied to determine the critical value, and the critical value may be determined by multiplying the reference quality factor value by the component factor, adding the tolerance to the product, and then subtracting the weighted value.

[0023] In addition, the foreign substance detection method may further include a step of starting charging of the identified wireless power receiver if the determination result indicates that no foreign substance is present, and a step of interrupting power transmission through the resonant circuit and outputting a predetermined alarm signal indicating that a foreign substance has been detected if the determination result indicates that a foreign substance is present.

[0024] Also, if the power transmission is interrupted, the device may return to the step of detecting an object placed in the charging area.

[0025] Furthermore, the foreign matter detection method may further include a step of comparing the measured quality factor value of the resonant circuit after the regression with the determined critical value to confirm whether the detected foreign matter has been removed from the charging area.

[0026] Furthermore, if the foreign substance is removed as a result of the check, the interrupted power transmission can be resumed.

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

[0028] In addition, the step of determining whether or not a foreign substance exists may include a step of determining that no foreign substance exists if the measured quality factor value exceeds the critical value, and a step of determining that a foreign substance exists if the measured quality factor value is equal to or less than the critical value.

[0029] According to another embodiment of the present invention, a method for detecting a foreign object in a wireless power transmitter having a resonant circuit for wirelessly transmitting power includes: detecting an object placed in a charging area; if the object is detected, measuring a quality factor value of the resonant circuit; identifying a wireless power receiver by transmitting a detection signal; determining a threshold range for detecting a foreign object based on a reference quality factor value received from the identified wireless power receiver; and determining whether a foreign object is present by comparing the measured quality factor value with the determined threshold range, wherein the threshold range is determined by applying an upper limit weight and a lower limit weight that increase depending on the reference quality factor value. It can be done.

[0030] According to yet another embodiment of the present invention, a foreign substance detection device includes a resonant circuit including a resonant capacitor and a resonant inductor, a sensing unit that detects an object placed in a charging area, a measurement unit that measures a quality factor value of the resonant circuit when the object is detected, and a control unit that determines a threshold value for foreign substance detection based on a reference quality factor value of a foreign substance detection status packet received from an identified wireless power receiver, and compares the measured quality factor value with the determined threshold value to determine whether or not a foreign substance is present, and the threshold value can be determined by applying a weight that increases depending on the reference quality factor value.

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

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

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

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

[0035] The foreign substance detection device also converts DC power applied from a power source into 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 panel are connected to each other so that a digital ping is periodically sent to identify the DC / DC converter and the front panel. and controlling the inverter to receive a signal strength indicator corresponding to the digital ping. , the wireless power receiver can be identified.

[0036] The measurement unit also measures the resonant voltage based on the voltage measured across the resonant 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 resonator; a sensing unit for sensing an object placed in the charging area; and When a body is detected, a measurement unit measures the quality factor value of the resonant circuit, and a wireless power The foreign substance detection status is determined based on the reference quality factor value of the foreign substance detection status packet received from the receiver. 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 exists based on the reference quality factor value. The upper and lower limit weights may be applied to determine the weight.

[0038] A wireless power transmitter including a resonant circuit for wirelessly transmitting power according to an embodiment of the present invention The foreign substance detection method 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 foreign matter based on the measured first inductance; and a step of comparing the temperature difference value 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 substance further includes the steps of: detecting an object placed in a charging area; and identifying the power receiver, wherein the measured first inductance value is This may include an inductance value of the resonant circuit that is changed by the sensed object.

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

[0041] The foreign object detection 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-evolution circuit before proceeding to the step of do.

[0042] The foreign substance detection method further includes determining whether or not the foreign substance is present by determining whether or not the wireless power supply is connected to the foreign substance. The method may further include interrupting power transmission to the receiver.

[0043] The foreign substance detection method further comprises: determining whether or not the foreign substance is present; The method may further include correcting the power transmitted to the wireless power receiver.

[0044] Further, the method for detecting foreign matter may include detecting whether a foreign matter is present or not based on the result of the determination of the presence or absence of the foreign matter. 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 substance detection method further includes detecting a second inductor of the resonant circuit after the power transmission is interrupted. measuring a second inductance value, and calculating the measured second inductance value and the determined critical value. and comparing the detected foreign matter to determine whether the foreign matter has been removed from the charging area. It can also include:

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

[0048] In addition, the reference inductance value is determined by the value of the inductance 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 the electric field may be included. .

[0049] In one embodiment, the foreign substance detection status packet further includes a mode field, The field indicates that the foreign substance detection status packet includes the reference inductance value. A first mode of indicating may be included.

[0050] In another embodiment, the foreign substance detection status packet further includes a mode field, The code field indicates that the foreign substance detection status packet contains the reference inductance value and the reference A second mode may be included to indicate the 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 by a preset ratio can be included.

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

[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 received power of 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 a line power receiver.

[0054] The step of determining whether or not the foreign substance exists may further include determining the quality factor value and the quality factor value. a first foreign substance determination step of determining whether or not a foreign substance exists 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. A second foreign substance determination step may be included.

[0055] In addition, at least one of the first foreign substance determining step and the second foreign substance determining step If it is determined that foreign substances are present at the judgment stage, it will be determined that foreign substances are present. can be done.

[0056] According to another embodiment of the present invention, a 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 substance detection status packet received from the wireless power receiver. and determining a threshold value for detecting foreign matter based on the first inductance value and the previous 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 the inductance of the resonant circuit changed by the sensed object. It may include an inductance value.

[0058] The measurement unit is configured to measure a quality factor value of the coevolution circuit, and the measured The detected quality factor value 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 stop power transmission to the wireless power receiver. This can be done.

[0062] The foreign substance detection status packet also includes 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 field indicates that the foreign substance detection status packet includes the reference inductance value. A first mode of indicating may be included.

[0064] In another embodiment, the foreign substance detection status packet further includes a mode field, The code field indicates that the foreign substance detection status packet contains the reference inductance value and the reference A second mode may be included to indicate the 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 by a preset ratio can be included.

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

[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 for determining whether a foreign substance is present, and a first foreign substance determination for determining whether a foreign substance is present or not; The second foreign substance judgment is performed by comparing the inductance critical value to determine whether or not foreign substances exist. can.

[0068] Further, the foreign substance is determined by at least one of the first foreign substance determination and the second foreign substance determination. If it is determined that a substance is present, the control unit ultimately determines that a foreign substance is present. can be done.

[0069] The foreign substance detection device also converts DC power applied from a power source into 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 panel are connected to each other so that a digital ping is periodically sent to identify the DC / DC converter and the front panel. and controlling the inverter to receive a signal strength indicator corresponding to the digital ping. , the wireless power receiver can be identified.

[0070] The measurement unit 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 voltage across the resonant capacitor. a quality factor measuring unit for calculating a quality factor value; and a voltage and current measuring unit for measuring the voltage and current measured at both ends of the inductor. and an inductance measurement 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 second 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, it can be determined that a foreign substance exists in the charging area. do.

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

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

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

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

[0078] Further, the foreign substance detection method may further include determining whether or not the presence of a foreign substance in the charging area is detected. 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 for detecting a foreign substance may further include detecting the foreign substance 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 determining whether the substance has been removed from the charging area. When the foreign matter is removed, the temporarily interrupted power transmission can be resumed.

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

[0082] Furthermore, the foreign substance detection method includes, after the alarm signal is output, before proceeding to the selection step: The method further includes the step of confirming whether the detected foreign matter has been removed from the charging area, If the foreign substance is found to be 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 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; charging 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, the value obtained by subtracting the second quality factor average value from the first quality factor average value is If the value exceeds a predetermined reference value, it can be determined that a foreign substance exists 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 within a wavenumber band; and determining whether a foreign substance exists in the charging area based on the quality factor value and the second quality factor value. and a detection unit.

[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 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 detects a wireless device that is not aligned with the charging area. It may also be determined that a power receiver is present.

[0090] Furthermore, the foreign substance detection device determines that a foreign substance is present in the charging area. The device may further include an alarm unit that outputs a predetermined alarm signal when detected.

[0091] Further, when the presence of the foreign substance is detected, the foreign substance detection device The power supply may further include a controller that temporarily suspends the power transmission.

[0092] The control unit may also determine whether the detected foreign matter is charged while the power transmission is temporarily stopped. If the detected foreign matter is removed from the electrical area, 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] After the alarm signal is output and before the selection step is started, the control unit It is checked whether the foreign matter has been removed from the charging area, and 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 less 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 exists.

[0096] According to another embodiment of the present invention, a foreign substance 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 quality factor value measured corresponding to a predetermined upper frequency band; A first quality factor average value is calculated, corresponding 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, and and a detector 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 voltage is high, 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 can also be done as follows.

[0099] Another embodiment of the present invention is a method for detecting foreign substances, comprising: It is possible to provide a computer-readable recording medium on which a program for performing the above-mentioned operations is recorded.

[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 are not necessarily the same. The various embodiments depicted are described in detail below by a person skilled in the art. These and other objects, features, and advantages of the present invention will become more apparent from the following detailed description of the invention. [Effects of the Invention]

[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 provides a method for detecting foreign substances that can detect foreign substances more accurately, and It would be advantageous to provide an apparatus and system for:

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

[0105] In addition, the present invention reflects a weighting value determined linearly or exponentially by the reference quality factor value. By dynamically determining the critical value or critical range for detecting foreign substances, It is advantageous to provide a wireless power transmission device that is 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 foreign matter 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 determines them based on the FOD status packet during the negotiation phase. By comparing the measured value with the critical value determined by the It would be advantageous to provide a possible foreign substance detection method and an apparatus and system therefor.

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

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

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

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

[0112] The effects obtained by the present invention are not limited to those mentioned above, and other effects not mentioned are The following description will be clearly understood by those skilled in the art to which the present invention pertains. Deaf. [Brief explanation of the drawings]

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

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

[0115] [Figure 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] [Figure 5] FIG. 2 is a diagram illustrating packet types according to an embodiment of the present invention.

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

[0119] [Figure 6b] FIG. 10 is a block diagram illustrating the 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. FIG.

[0121] [Figure 7b] 10 is a diagram illustrating the message structure of an FOD status packet according to one embodiment of the present invention.

[0122] [Figure 7c] 10 is a diagram illustrating a message structure of an FOD status packet according to another embodiment of the present invention.

[0123] [Figure 8a] 4A and 4B are diagrams illustrating a state transition process for detecting foreign matter in a foreign matter detection device according to an embodiment of the present invention.

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

[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] 10 is a graph showing experimental results illustrating the degree to which a perceived quality value decreases 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] 10 is a graph showing experimental results illustrating the degree to which a perceived quality value decreases 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 inductance value for the resonant circuit are shown for each receiver type and whether or not foreign matter is present.

[0129] [Figure 13a] 10 is a diagram illustrating a message structure of an FOD status packet according to yet another embodiment of the present invention.

[0130] [Figure 13b] 10 is a diagram illustrating a message structure of an FOD status packet according to yet another embodiment of the present invention.

[0131] [Figure 13c] 10 is a diagram illustrating a message structure of an FOD status packet according to yet another embodiment of the present invention.

[0132] [Figure 13d] 10 is a diagram illustrating the message structure of an FOD status packet according to one embodiment of the present invention. [Figure 13e] 10 is a diagram illustrating the message structure of an FOD status packet according to one embodiment of the present invention. [Figure 13f] 10 is a diagram illustrating the message structure of an FOD status packet according to one embodiment of the present invention. [Figure 13g] 10 is a diagram illustrating the message structure of an FOD status packet according to one embodiment of the present invention.

[0133] [Figure 14] 10 is a flowchart illustrating a method for detecting FOD according to another embodiment of the present invention.

[0134] [Figure 15] 10 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 illustrating the configuration of an FO detection device according to an embodiment of the present invention.

[0137] [Figure 18] 10 is a flowchart illustrating a method for detecting FOD according to yet another embodiment of the present invention.

[0138] [Figure 19] 10 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] 21 is a block diagram illustrating the structure of an FO detection device corresponding to the embodiment of FIG. 20. FIG.

[0141] [Figure 22] 10 is a flowchart illustrating a method for detecting an FO based on a quality factor value according to another embodiment of the present invention.

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

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

[0144] [Figure 25] 10 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] 4A and 4B are diagrams illustrating a state transition process for detecting foreign matter in a foreign matter detection device according to an embodiment of the present invention.

[0146] [Figure 27] 10 is a diagram illustrating a message structure of an FOD status packet according to another embodiment of the present invention.

[0147] [Figure 28] 4A and 4B are diagrams illustrating a state transition process for detecting foreign matter in a foreign matter detection device according to an embodiment of the present invention.

[0148] [Figure 29] 4A and 4B are diagrams illustrating a state transition process for detecting foreign matter in a foreign matter detection device according to an embodiment of the present invention.

[0149] [Figure 30] 10 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 INVENTION

[0150] In one embodiment, a wireless power transmitter having a resonant circuit for wirelessly transmitting power is provided. The foreign substance detection method includes the steps of detecting an object placed in a charging area, and detecting the object when the object is detected. For example, measuring a quality factor value of the resonant circuit and transmitting a sensing signal to the wireless power receiver. and determining a reference quality factor value based on the 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 the determined quality factor value; and determining whether or not a foreign substance is present by comparing the determined critical value with the reference critical value. The weighting factor may be determined by applying an increasing weighting factor according to the quality factor value. MODE FOR CARRYING OUT THE INVENTION

[0151] Hereinafter, the apparatus and various methods to which the embodiments of the present invention are applied will be described in more detail with reference to the drawings. The suffixes "module" and "section" for components used in the following description are for clarity. They are given or mixed with other terms in consideration of the ease of creating detailed specifications, and are not distinguishable from each other as such. It does not have a different meaning or role.

[0152] In the description of the embodiments, when it is described as being formed "above or below" each component, In this case, the upper or lower means two components in direct contact with each other or one or more further components. It also includes the case where the "above or below" is placed between two components. In this case, it can mean not only above but also below one component.

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

[0154] The transmitter according to the present invention may be in the form of a pad, a fixed type, or an AP (Access Point). It can be configured in various forms, including a small base station, a stand, a ceiling-mounted form, and a wall-mounted form. One transmitter can also transmit power to multiple wireless power receiving devices. To this end, the transmitter may also comprise at least one means for wireless power transmission. The line power transmission means generates a magnetic field in the 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, where electricity is induced in the end coil. Various wireless power transmission standards can be used. WPC (Wireless Power Consortium), the charging technology standard organization ) and the electromagnetic induction defined by PMA (Power Matters Alliance) 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 Organization) 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 mobile phones, smartphones, smartphone, laptop computer , digital broadcasting terminals, PDAs (Personal Digital Assistants) nts), PMP (Portable Multimedia Player), navigation game smartphones, MP3 players, electric toothbrushes, electronic tags, lighting devices, remote controls Used for small electronic devices such as radar, floats, and wearable devices like smartwatches. However, the present invention is not limited to this. Any device that can charge a battery is sufficient.

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

[0159] For example, the wireless power transmitting end 10 and the wireless power receiving end 20 are used for wireless power transmission. In-band communication is performed by 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. 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 for wireless power transmission. Out-of-band (OUTB) communication is a method of exchanging information using a separate frequency band different from the operating frequency. d) Communications can also be carried out.

[0162] For example, information exchanged between the wireless power transmitting end 10 and the wireless power receiving end 20 is The information exchanged between the transmitting and receiving ends can include not only status information but also control information. The status information and control information will become more apparent from the description of the embodiment below.

[0163] The in-band and out-of-band communications may provide two-way communication, but are not limited to this. Alternatively, other embodiments may provide for simplex or half-duplex communication. do.

[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, and the wireless power transmitting end 10 may be a wireless power receiving end 20. It may also transmit information to

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

[0166] The wireless power receiving end 20 according to an embodiment of the present invention acquires various status information of the electronic device 30. For example, the status information of the electronic device 30 may include current power usage information, execution information, and the like. Information to identify the application in use, CPU usage information, battery charge status information, battery - The output voltage / current information may include, but is not limited to, the output voltage / current information from the electronic device 30 Any information that can be obtained and used for wireless power control is sufficient.

[0167] In particular, the wireless power transmitter 10 according to an embodiment of the present invention may include a predetermined The packet can be transmitted to the wireless power receiving end 20. The wireless power receiving end 20 If it is confirmed that the wireless power transmitting terminal 10 supports the fast charging mode, This can be notified to the electronic device 30. The electronic device 30 has a predetermined display means, The indication that fast charging is possible is displayed via a display means, which may be, for example, a liquid crystal display. It is possible.

[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. The wireless power transmitting end 10 can also 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 fast charging request signal can be transmitted to the wireless power receiving terminal 20. generates a charging mode packet corresponding to the received fast charging request signal and transmits it to the wireless power transmitting end 10, it can convert the general low-power charging mode to 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 condition occurs while initiating power transfer or maintaining power transfer. may be a transition state when a specific event is detected. The specific events will become clear from the following description. Also, in the selection step 210: The transmitter can monitor the presence of an object on the interface surface. If the transmitter senses that an object has been placed on the interface surface, it performs a ping step 22. In the selection step 210, the transmitter generates a very short pulse of analog The transmitter coil or the primary coil (Primary coil) transmits an Analog Ping signal. The active area on the interface surface is determined based on the current change in the ry coil. It can sense whether an object is present in the area.

[0172] In the ping step 220, if the transmitter senses an object, it activates the receiver, and the receiver Digital Ping to identify receivers that are compatible with PC standards In the ping step 220, the transmitter transmits a response signal to the digital ping. If a signal, e.g., a signal strength packet, cannot be received from the receiver, the selection stage is restarted. In the ping stage 220, the transmitter can receive 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 returns the receiver configuration and status information. The process may proceed to an identification and configuration step 230 for collection.

[0174] In the identification and configuration step 230, the transmitter determines whether unwanted packets are received (unex expected packet), if the desired packet is not received within a predefined time There is a time out or a packet transmission error. n error), if no power transfer contract is set (no power transfer The process may proceed to a fer contract selection step 210.

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

[0176] If the result of the check indicates that negotiation is necessary, the transmitter proceeds to negotiation step 240 to determine whether a predetermined FOD detection is necessary. The process can be carried out.

[0177] On the other hand, if the result of the check indicates that negotiation is not necessary, the transmitter immediately proceeds to the power transmission step 260. You can also do this.

[0178] In the negotiation stage 240, the transmitter receives a Foreign Object Descriptor (FOD) containing a reference quality factor value. Inject Detection) status packet 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 amount of foreign matter by using a predetermined critical generating function with the reference quality factor value as a parameter. A critical value or critical range can be determined to determine whether or not a substance exists. 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 preset configuration factor (De sign_factor), tolerance and weighting defined in the standard The weighting factor can be determined based on the reference quality factor value, where the weighting factor is linearly proportional to the reference quality factor value. Or it can increase exponentially. That is, the critical value for detecting foreign substances can be calculated by the following formula: 1:

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

[0180] can be determined by

[0181] Generally, if a foreign object is placed in the charging area, the quality factor value measured by the resonant circuit of the transmitter In fact, in a wireless charging system, if a foreign substance is placed in the charging area, the When a substance is placed, the rate at which the measured quality factor value decreases relative 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 reference 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 foreign matter 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 foreign substances 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 detection results, it is possible to determine whether FO exists in the charging area. For example, if FO is detected, the transmitter can control the power transmission. and outputs a predefined warning alarm indicating that an FO has been detected. It is possible.

[0183] If FO is detected, the transmitter can return to selection step 210. If no power is detected, the transmitter goes through a correction stage 250 and enters a power transmission stage 260. In particular, if FO is not detected, the transmitter may adjust the receiving end in a correction step 250. The strength of the power received at the transmitting 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. In one embodiment, the transmitter may calculate a critical frequency for FOD detection based on the 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 within a predefined period of time. (time out), or a violation of an already established power transmission contract (p Power transfer contract violation) Charging is complete If so, a transition to selection step 210 can be made.

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

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

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

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

[0189] The wireless power receiver 300 shown in the example of FIG. 3 transmits a wireless power signal to a wireless power transmitter via in-band communication. 600, this is only one example. In addition, the communication unit 360 according to another embodiment of the present invention uses a frequency band used for wireless power signal transmission. It can also provide short-range two-way communication over a different frequency band.

[0190] The AC power received through the receiving coil 310 can be transmitted to the rectifier 320. The rectifier 320 converts AC power into DC power and transmits it to the DC / DC converter 330. The DC / DC converter 330 adjusts the intensity of the rectifier output DC power depending on the load 340. After being converted to a specific 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. 0. 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 can be transmitted to the wireless power transmitter 600 via a 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 voltage between the receiving coil 310 and the rectifier 320. The power signal or the DC power signal output from the rectifier 320 is demodulated to determine whether or not the sensing signal is received. 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 illustrating 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 synchronization acquisition for demodulation of the corresponding packet and for 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 If an error occurs in the Message 430 field or the corresponding packet, Contains a checksum 440 field to verify that the It can be done in.

[0195] The packet receiving end receives the message 420 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) of the Ping phase Power Transfer) and header value corresponding to the end of power transfer in the power transfer phase It should be noted that both are 0x02 and are identical.

[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. It can be a request or a response, This is not limited to this.

[0198] The packet 400 according to another embodiment of the present invention identifies the transmitting end that transmitted the corresponding packet. receiving end identification information for identifying a receiving end that receives the corresponding packet; In this case, at least one of the transmitting end identification information and the receiving end identification information may be included. The identification information may include IP address information, MAC address information, product identification information, etc. Without being limited thereto, information that can distinguish a receiving end from a transmitting end in a wireless charging system It is sufficient if the information is correct.

[0199] A packet 400 according to yet another embodiment of the present invention is a packet that is sent by multiple devices. If the data must be received by a specific group, a predetermined group identifier must be used to identify the receiving group. It may also contain other information.

[0200] FIG. 5 shows a power distribution diagram of a wireless power receiver according to an embodiment of the present invention. FIG. 10 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. 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, Power Control Hold (PCH) for transmitting time information to wait before adjusting the power Controller Hold-off packet, and 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 is used to transmit a message, and a special request packet is used to transmit a special request message. a FOD request packet, an FOD status packet for transmitting a reference quality factor value for FOD detection, A control error packet for controlling the transmitter's transmission power, and a renegotiation packet for starting renegotiation. 24-bit received power packet and 8-bit received power packet for transmitting received power strength information The power packet includes a power packet and 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 can be transmitted using in-band communication using the same frequency band as the signal being transmitted.

[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 DC Converter 610, Inverter 620, 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 substance detection device 600 according to this embodiment is attached to a wireless power transmission device. It can be done.

[0205] The resonant circuit 630 comprises 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. 0 can be transmitted.

[0207] The DC / DC converter 610 receives the input from the power supply unit 601 under the control of the control unit 680. The intensity of DC power can be converted to DC power of a specific intensity. The converter 610 may be a variable voltage converter capable of adjusting the voltage strength, but is not limited thereto. It will not be 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 plurality of switches provided therein. It can be converted into an electric 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. It may also comprise e).

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

[0211] According to an embodiment of the present invention, a wireless power transmitting device receives power requested by a wireless power receiving device. The bridge mode of the inverter 620 can be adaptively controlled according to the strength of the power. Here, the bridge mode includes a half-bridge mode and a full-bridge mode.

[0212] For example, if 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 15 W of power, the control unit 680 operates in full-bridge mode. It can be controlled to operate in this way.

[0213] As another example, the wireless power transmitting device may be configured to adaptively switch to bridge mode according to the sensed temperature. and drive the inverter 620 in the determined bridge mode. As an example, a wireless power transmission device transmitting 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. and activates the full-bridge mode. The power transmitter uses a full bridge circuit to increase the voltage for the same power transmission. By reducing the intensity of the current flowing through the resonant circuit 630, The temperature of the part can be controlled to be maintained at or below a predetermined reference value.

[0214] Generally, the amount of heat generated by electronic components installed in electronic devices is determined by the amount of heat applied to the electronic components. It may be more sensitive to the current intensity than the voltage intensity.

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

[0216] For 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 power output by adjusting the AC power frequency. For this purpose, the inverter 620 is a frequency converter that generates a reference AC signal having a specific frequency. Although this is only one example, in other examples it may comprise a frequency oscillator. The oscillator is constructed separately from the inverter 620 and is attached to one side of the foreign substance detection device 600. It is possible.

[0217] As another example, the foreign substance detection device 600 may control a switch provided in the inverter 620. It further includes a gate driver (not shown) for controlling 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 and drive the inverter according to the received pulse width modulated signal. The control unit 680 can control the switch of 620. Duty Cycle, i.e., 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 the duty cycle and phase of a pulse width modulated signal based on the signal can be done.

[0218] The measuring 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 calculated quality factor can be calculated based on the value and / or the inductance value. The value and / or inductance value is transmitted to the control unit 680, and the control unit 680 stores the value and / or inductance value in a predetermined storage area. The quality factor value and / or the inductance value transmitted from the measurement 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 can be controlled to calculate

[0219] If the FOD status packet is received 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. 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 calculates the following equation 1:

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

[0222] The critical value for detecting foreign substances can be determined by the above method.

[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 quadratic or higher order function. It is also possible.

[0224] As another example, the weighting value may be predefined for each type of wireless power receiver. 0 can be recorded and maintained in a predetermined recording area, for example, a non-volatile memory. , the weighting values ​​for each type of wireless power receiver may be maintained in the form of a mapping table. However, this is not limited to this.

[0225] In another embodiment, the threshold range for detecting foreign matter is the upper threshold (FO_Threshold _Upper_Limit) and lower critical limit (FO_Theshold_Lower_Li 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 weighted value and lower weighted value are determined based on the Here, the upper and lower limit weights can be linearly or exponentially adjusted 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 (Equation 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) value. 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 is set to 40%. The critical value (FO_Threshold) is RQF x 0.66 + tolerance nce).

[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 difference ratio is applied as 10%. The critical 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 an FOD status packet during a negotiation phase; The FO_Threshold can 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 increases according to the difference ratio corresponding to the RQF value. The difference between the RQF value and FO_Threshold is the difference corresponding to the RQF value. The above Table 1 is only 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] Generally, if a foreign object is placed in the charging area, the quality factor value measured by the resonant circuit of the transmitter In fact, in a wireless charging system, if a foreign substance is placed in the charging area, the When a substance is placed, the rate at which the measured quality factor value decreases relative 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 controls the wireless communication device with a large reference quality factor value. In the case of a power receiver, the ratio of the critical value for detecting foreign matter to the reference quality factor value is The critical value (or critical range) can be determined so that the transmitter The probability of failing to detect foreign substances can be reduced.

[0236] The control unit 680 determines the quality factor value measured after object detection and the clinical value determined for 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 power transmission 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 indicating that an FO has been detected. Here, the warning alarm is a beeper, an LED lamp, etc., provided in the foreign substance detection device 600. The signal can be output 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 decided.

[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, there is a foreign substance in the charging area. It can also be judged that:

[0240] The reference quality factor value included in the FOD status packet is a value specified for standard performance testing. The quality factor 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 substance is detected during the negotiation stage, the control unit 680 returns to the selection stage and The measuring unit 640 can be controlled to calculate the quality factor value of the resonant circuit 630 periodically. do.

[0242] At this time, the control unit 680 has already determined the quality factor value obtained when the foreign substance 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 whether the quality factor value measured in the state where the foreign substance is detected has already been If the value is greater than the determined critical value, it can be determined that the foreign substance has been removed. The control unit 680 determines whether the quality factor value measured in the state where the foreign substance is detected is equal to or exceeds the upper limit critical value. If the value exceeds this, it can be determined that the foreign substance has been removed.

[0244] In addition, the control unit 680 uses the above-mentioned Table 1 (hereinafter, for convenience of explanation, referred to as 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 storage 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. If a status packet is received, the received reference quality factor value and the threshold value determination table are referenced. The critical value for detecting foreign substances 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 results.

[0246] Here, the threshold value determination table can 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 the 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 determines whether or not a foreign object is present by referring to a threshold value determination table corresponding to the identified type of wireless power receiver. A threshold value for quality detection can 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 be configured to recognize the type of wireless power transmitter 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 foreign matter based on the received threshold value determination table. It can also be done as follows.

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

[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 resume.

[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 substances, and 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 contains a reference quality factor value or ( and) a reference inductance value. A quality factor for determining whether or not foreign matter exists 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 inductance The ratio can be determined as a critical value of the resistance, but is not limited thereto, and the ratio can be determined by those skilled in the art. It can be defined differently depending on the system.

[0253] As an example, the control unit 680 may use the quality factor values ​​already stored (measured before the ping phase). If the quality factor is smaller than the determined critical value or the inductance value already stored is If the inductance is smaller than the specified critical value, it can be determined that a foreign substance exists. do.

[0254] If it is determined that a foreign substance is present, the control unit 680 stops power transmission and The device can be controlled to output a predetermined warning alarm indicating that a malfunction has been detected. For example, notification means 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 on the charging bed of the wireless power transmitter The minimum of the inductance values ​​can be determined.

[0257] Also, if a foreign substance is detected during the negotiation stage, the control unit 680 returns to the selection stage and The measurement unit 640 calculates the quality factor value and the inductance value of the resonant circuit 630 every In this case, the control unit 680 may control the foreign substance detection state. The quality factor value and inductance value determined are compared with the previously determined critical quality factor value and inductance value, respectively. Compare with the inductance threshold to determine whether the foreign substance already detected has been removed from the charging area. As an additional example, if the foreign substance is removed as a result of the determination, the control unit 6 80 enters the power transmission stage and controls the corresponding wireless power receiving device to 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 it to the control unit 680. For 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), Measure voltage, current, power, impedance, temperature, etc. at specific elements or specific locations 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 the information on whether or not overheating has occurred. and providing the measurement result to the control unit 680. In this case, the control unit 680 may measure 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 is supplied to the resonant circuit 630. For this purpose, one side of the foreign substance detection device 600 is connected to a power source. The power supplied from the unit 601 is cut off, or the DC power supplied to the inverter 620 is cut off. The power supply may further include a predetermined power cutoff circuit for cutting off the power.

[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 the resonant circuit while transmitting the analog ping signal in the selection step. 630 detects changes in current, voltage, impedance, etc., and detects the presence of an object in the charging area. It can also sense the

[0263] As described above, the foreign substance detection device 600 according to the present invention detects an object in the selection stage. If so, the quality factor value of the resonant circuit is measured (or calculated) before proceeding to the ping stage, and The presence of foreign matter is detected by comparing the measured quality factor value with the critical value (or critical range) determined at the stage. By determining whether or not a foreign substance is present, the probability of failing to detect the foreign substance can be significantly reduced. There is a point.

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

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

[0266] A detailed description of the operation of the remaining components shown in FIG. 6b is given in the description of FIG. 6a above. Switch.

[0267] FIG. 7a shows a foreign object detection status packet according to one 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, and 2 bits long Mode 702 field and a 1-byte long reference quality factor value ence Quality Factor Value) 703 field 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 of the wireless power receiver is turned off. This may mean that the reference quality factor value determined by measuring the quality factor is recorded.

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

[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 de)702 field and a 1-byte long Reference Quality Factor value (Reference Qu The metric may include a Quality Factor Value 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 is determined by measuring the wireless power receiver in the condition that the power is turned off. If the Mode 702 field is set to binary '01', the quality factor value is recorded. The first data 701 field contains the data measured when the power of the wireless power receiver is turned off. The reference inductance value determined by the setting 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 power receiver. It is possible.

[0274] FIG. 7c illustrates the 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, and 2 bits long Mode 702 field and 1-byte length Reference The Reserved 701 field may include a Reserved 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 should be measured when the power of the wireless power receiver is turned off. The reference quality factor value determined by the above method is recorded. If set to '01', the reference value 703 field indicates that the power supply of the wireless power receiver is OFF. 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) Obtaining 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 shows a state transition process for detecting foreign matter in a foreign matter 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 substance detection device selects a resonant After measuring and storing the quality factor values ​​of the circuit, the 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 can be transmitted periodically.

[0280] The foreign substance detection device receives a signal strength indicator corresponding to the digital ping in ping step 820. If the wireless power receiver is received, the process proceeds to the 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 complete, the foreign substance detection device proceeds to negotiation step 840. and receives an FOD status packet containing 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. The 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) 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 substance is placed in the The ratio is relatively small or low compared to wireless power receivers with a large ratio. The foreign substance detection device according to one embodiment of the present invention detects a foreign substance based on a reference quality factor value received from a wireless power receiver. Therefore, the threshold value (or threshold range) for detecting foreign substances can be adaptively determined.

[0284] If the foreign substance is detected, the foreign substance detection device stops 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 shows a state transition process for detecting foreign matter in the foreign matter detection device according to an embodiment of the present invention. FIG.

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

[0287] If the signal strength indicator is received in ping step 820, the foreign substance detection device identifies and configures The process proceeds to step 830, where the wireless power receiver is identified, and various settings for the identified wireless power receiver are You can set the configuration parameters for

[0288] Once the identification and configuration of the wireless power receiver is complete, the foreign substance detection device proceeds to negotiation step 840. and a FOD state packet containing a reference quality factor value and / or a reference inductance value is sent. You can receive the message.

[0289] The foreign substance detection device determines whether foreign substances are present based on the reference values ​​(etc.) included in the FOD status packet. Determine the critical value (or critical range) to determine whether or not there is a problem, and Based on the result, it is possible to determine whether a foreign substance is present in the charging area.

[0290] If the foreign substance is detected, the foreign substance detection device stops 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 proceeding to the power transmission step 850, the foreign substance detection device 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 transmitting 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 transmitting device can check whether a foreign object has been detected previously. (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 begins. Once the identification and configuration of the wireless power receiver is complete, the negotiation stage begins. You can transition to the next floor (S904).

[0296] The wireless power transmitter receives the reference quality factor included in the FOD status packet during the negotiation phase. Determine the critical value (or critical range) to determine the presence or absence of foreign matter based on the value of the Here, the method for determining the critical value and the critical range is the same as that shown in FIGS. The wireless power transmitting device transmits a power signal of a predetermined strength wirelessly during 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 or not a foreign substance exists on the charging area (S906).

[0298] If the foreign object is detected, the wireless power transmitting device stops transmitting the power signal and The control can be performed to output a predetermined warning alarm indicating that (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 matter is present, the wireless power transmitting device transmits power. The wireless power receiver can then start charging by entering the transmission step (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 matter has been removed from the charging area (S910 Here, the method for 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 Figures 6a to 8b.

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

[0302] If the detected foreign matter is not removed as a result of the judgment in step 910, wireless power The transmitting device can perform the above-described step 901.

[0303] FIG. 9b is a diagram illustrating a method for detecting a foreign object in a wireless power transmitting 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 begins. Once the identification and configuration of the wireless power receiver is complete, the negotiation stage begins. You can 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 whether or not the substance is present can be determined (S905). Here, the critical value 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 transmitting 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 is then possible to determine whether or not a foreign substance exists on the charging area (S906).

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

[0311] If it is determined in step 906 that no foreign matter is present, the wireless power transmitting device transmits power. The wireless power receiver can then start charging by entering the transmission step (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 matter 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 are compared with the critical value ( or critical range), but is not limited to this.

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

[0314] If the detected foreign matter is not removed as a result of the judgment in step 910, wireless power The transmitting device can perform the above-described step 901.

[0315] As described above, the wireless power transmission device according to the present invention detects an object in the selection step. If so, the quality factor and inductance values ​​of the resonant circuit are measured (or calculated) and the critical value determined based on the FOD status packet received during the negotiation phase and the measurement By comparing the values ​​to determine whether or not a foreign substance is present, the probability of failing to detect a foreign substance is reduced. This has the advantage of being able to lower the

[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. 10 is a graph showing experimental results showing the degree to which perceived quality values ​​are reduced compared to reference quality factor values;

[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 dime 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 This indicates that the quality factor increases as the 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 1011. No. 1011 is approximated by a quadratic equation, but this is only an example and may be approximated by a linear equation or other equations. 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 dime is placed in the charging area. After the setting, the rate at which the quality factor value drops compared to the reference quality factor value (%diff1) is It shows that the value of the factor increases as the value of the factor increases. The measured quality factor (NO_FO) value, i.e., the reference quality factor (RFQ) value and the %dif The relationship between f1 and f2 can be approximated by the equation 1021. Although 021 is approximated by a quadratic equation, this is only an example and may be approximated by a linear equation or other high-order equations. It should be noted that the equations can be approximated by quadratic equations, exponential equations, etc. .

[0320] FIG. 11 shows a receiver type when a foreign object is placed in the charging area according to another embodiment of the present invention. 10 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 This indicates that the quality factor increases as the value increases. The measured quality factor (NO_FO) value, 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 an example and can be approximated by a linear equation, other 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 is placed in the charging area. After the setting, the percentage of the quality factor value that decreases compared to the reference quality factor value (%diff2) is It shows that the value of the factor increases as the value of the factor increases. The measured quality factor (NO_FO) value, i.e., the difference between the reference quality factor (RFQ) value and the The relationship between the two can be approximated by the equation 1121. 21 is approximated by a quadratic equation, but this is only an example and can be used with linear equations or other higher-order equations. It should be noted that the equations can be approximated by equations, exponential equations, etc.

[0324] As described above, the wireless power transmission device 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 proceeding to the ping stage, and The measured quality factor value is compared with a critical value determined based on the received FOD status packet. By determining whether or not a foreign substance is present, the probability of failing to detect a foreign substance is significantly reduced. This has the advantage of being able to

[0325] Figure 12 shows the quality factor and inductance for each receiver type with and without foreign material for the resonant circuit. The measurement results of the coherence value are shown below.

[0326] The reference numeral 1210 indicates a state where nothing is placed in the charging area 1211, and a state where only foreign matter 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] The reference numeral 1220 indicates a receiver type in which a foreign substance and a receiver are placed together in the 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 transmitting device. The inductance of the resonant circuit measured in the empty pad state was 25.20μm. H and the quality factor value is 133.8.

[0329] Referring to the reference numeral 1210, when nothing is placed in the charging area, a foreign substance, e.g. When foreign materials, 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 substance If the receivers are placed in a different location, the quality factor values ​​will all decrease. In this case, the quality factor value is lower than that of FO#4.

[0331] Referring to the reference numeral 1220, when the receiver is placed in the charging area, the standard foreign material is If FO#4 and 10 cent coins are also placed, the drawing numbers are 1221 and 1222. As shown in 222, both the inductance value and the quality factor value are low. The rate at which the coherence and quality factor values ​​decrease varies depending on the type of receiver. Referring to surface reference numbers 1213, 1221 and 1222, in the case of receiver 1, the foreign substance 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 measured rather than the inductance value to determine whether or not there is a foreign substance. 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 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 the receiver 4, in order to determine whether or not there is a foreign substance, the inductance is calculated based on the quality factor value. It may be advantageous to sense changes in the sense value.

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

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

[0334] Thereafter, the wireless power transmitter will make a different decision based on the FOD status packet received during the negotiation phase. The critical inductance value and the critical quality factor value 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 results.

[0335] As an example, the wireless power transmission device may compare the stored inductance value with the determined inductance. The presence of foreign matter is determined by comparing the critical value of the tank with the stored quality factor value. If it is determined that foreign matter exists compared with the quality factor critical value, the charging area is finally It can be determined that a foreign substance is located in the

[0336] In the above-described embodiment, the wireless power transmission device detects a foreign object based on the FOD status packet. However, this is only an example and the critical range is not In this case, the wireless power transmitting device can determine the range of the inductance If the value and / or quality factor value falls outside the determined critical range, it is determined that foreign matter is present. You can also do this.

[0337] According to another embodiment of the present invention, a method for detecting a foreign object in a wireless power transmitting 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 power or load connection status may include the received power of the wireless power receiver corresponding to the power or load connection status.

[0338] FIG. 13a illustrates the 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 A 1340 field and a 2-bit long Mode field It may comprise

[0340] The wireless power transmitter according to one embodiment of the present invention is measured at the operating frequency with the maximum quality factor value. If there is an operating frequency in the upper band at which a quality factor value higher than the determined 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 with 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 that operates at an operating frequency having a maximum quality factor value. The quality factor peak operating frequency in the band above the ping stage (the value of the quality factor measured before the ping stage) If there is an operating frequency at which the maximum quality factor value is measured, it means that there is a foreign substance in the charging area. It can be determined that this is the case.

[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. At the operating frequency for the maximum quality factor value corresponding to the type of wireless power transmitter identified in 0 For example, a wireless power transmitter type can be connected to the wireless power receiver for this purpose. 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, and manufacturing of the wireless power transmitter. Varies depending on company, applied standards, etc.

[0343] Therefore, what operating frequency or 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 over which the quality factor value must be measured for searching can be minimized. That is, the wireless power transmitter operates 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 part.

[0344] As another example, the operating frequency for the maximum quality factor value 1341 is defined in the WPC standard A coil type may be, but is not limited to, a specific coil type, for example, an MP-A1 type. The operating frequency for the maximum quality factor value corresponding to the wireless power transmitter equipped with the type of transmitting coil is This is based on the MP-A1 type, and other types of wireless power transmitters The magnitude of the received maximum quality factor value is adjusted (sca) to take 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. (previous step) measures and stores the quality factor value a1 for a specific upper limit frequency of the operating frequency band. Alternatively, measurements can be made within a set frequency range (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 1 is greater than a2, it can be determined that a foreign substance exists in the charging area. The wireless power transmitter receives the FOD status packet 1340 during the negotiation phase 240. The operating frequency and the frequency measured in the ping phase 220 (or before the ping phase) for the maximum quality factor value obtained. The presence or absence of foreign matter can be determined by comparing the maximum quality factor obtained with the measured frequency. .

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

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

[0348] In still another embodiment, a 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 only one example, and other examples may be used to determine the quality factor values ​​for the 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. For example, the operating frequency of the wireless power transmitter may be The frequency band is between the lower limit frequency of 100KHz and the upper limit frequency of 300KHz, and the offset The frequency is 10 kHz 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 select 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 operating frequency for the maximum quality factor value of FIG. 13a is inserted. 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 that results in a lower value can also be inserted into field 1341 .

[0353] The wireless power transmitter may 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 the 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 Figure 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 a 1-byte length Reference Quality Factor value r Value) 1353.

[0357] The wireless power transmitter shall report the maximum quality level in the FOD status packet received by the Mode 1352 value. You can also check whether the operating frequency 1351 for the quality factor value is included, but this is not the only The maximum quality factor is always applied to FOD state 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 shown in 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 operating frequency and ping for the maximum quality factor value (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, example 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) are set. The threshold 1 and threshold 2 (Q_Threshold2) can be determined. 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 device can determine that a foreign substance is present.

[0362] Is the quality factor value measured before the ping step 220 less than critical value 1 and equal to 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 the 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 Figure 13c, the FOD status packet message 1360 has a length of 2 bytes. 6-bit long wireless power transmitter type (Tx Type) 1361, 2 A Mode 1362 field of bit length and a 1-byte long maximum quality factor value Operating Frequency for Maximum m Quality Factor Value) 1363 field. can be done.

[0365] The wireless power transmitter determines the wireless power status by the mode 1362 value in the received FOD status packet. Contains transmitter type 1361 information and operating frequency 1363 information for maximum quality factor value This can be, but is not limited to, checking whether the mode is set to 1362, regardless of the value. The FOD status packet always contains the wireless power transmitter type 1361 information and the maximum quality factor value. The operating frequency 1363 information for the

[0366] For example, the wireless power transmitter type 1361 is a wireless device registered at the time of WPC (Qi) certification. A predetermined transmitter design number (Tx Design Number) to uniquely identify the power transmitter. It can be a value (predetermined classification number) indicating the size of the object.

[0367] As another example, the Wireless Power Transmitter Type 1361 shares common design features and performance characteristics. It can 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 with the maximum quality factor value. If there is an operating frequency in the upper band at which a quality factor value higher than the determined 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 with 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 that operates at an operating frequency having a maximum quality factor value. The quality factor of the upper band is the peak operating frequency (measured before the ping stage) If there is an operating frequency at which the maximum quality factor value is measured, there is a foreign object in the charging area. It can be determined that quality exists.

[0370] For the sake of convenience, the reference quality factor 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 specific foreign substance is an aluminum alloy with a diameter of 22 mm and a thickness of 1 mm. Foreign Object #4, a minium disc (hereafter, for the sake of convenience, (This can be mixed with FO4), but is not limited to this, and can be any common copper coins. You can also use either one.

[0371] Before the wireless power transmitter performs the ping step, i.e., during 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 account for technical differences urement tolerance) and the reference quality factor Accuracy f Reference Quality Factor) to determine whether or not there are any foreign substances. A critical value of the quality factor for determining nullity is determined.

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

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

[0374] As another example, the reference quality factor drop value 1321 is the value measured when no foreign material is present. It is the ratio of the drop in the quality factor value measured in the presence of foreign matter to the quasi-quality factor value. In this case, the reference quality factor drop value 1321 is calculated as a percentage (%) or It can be an integer value calculated by dividing the rate by a specific step value (STEP_VALUE). 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 *100 is not reflected in the actual value. 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 senses the reference quality factor drop value. The quality factor drop value is taken into account when determining whether or not a foreign substance is present. The quality factor threshold for the quality factor can be adaptively determined.

[0381] Therefore, the present invention is capable of detecting foreign matter in a normal state 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 the 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 and 2-bit long Model Mode 1302 field and a 1-byte long reference quality factor value The CE Quality Factor Value (CEFV) may comprise 1303. do.

[0384] All bits that make up the Reserved 1301 field can be set to 0.

[0385] Referring to drawing reference numeral 1304, if the mode 1302 field is binary '00', The reference quality factor (RQF_NO_FO, first reference quality factor) value in the absence of FO is the reference quality factor. The quality factor value 1303 field is recorded, and the mode 1302 field is If the digit is '01', the reference quality factor (RQF_FO, second reference quality factor) is present. This may mean that the reference quality factor value 1303 is recorded in the reference quality factor value 1303 field.

[0386] FIG. 13e illustrates the 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 and 2-bit long Mode Mode 1312 field, Reference Quality Factor value ty Factor Value)1313 and Reference Quality Factor Value when foreign matter is present (Ref erence Quality Factor Value With Foreign Object) 1314.

[0388] All bits that make up the Reserved 1301 field can be set to 0.

[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 when the wireless power receiver is turned 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 detects a reference voltage measured when no foreign substance is present. The presence 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 varies depending on the presence of foreign matter. This occurs when a foreign substance is not detected properly even though it is actually located in the charging area. This minimizes problems such as overheating and a drop in power transmission efficiency.

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

[0393] Referring to Figure 13f, the FO Status Packet message 1120 has a length of 2 bytes. The Drop Value of Re is 6 bits long. Interference Quality Factor (IQF) 1321 field, 2 bits long Mode 1322 field, Reference Qua 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 (Quality Factor) measured when the factor value 1223 and specific foreign substances are present The ctor value with foreign object is determined based on the It can be any value.

[0395] The Mode 1322 field is the reference quality factor drop value in the Reserved 1301 field of FIG. 13d. 1321 can be used to indicate that the Referring to the plane code 1324, if the value of the mode 1322 field is binary '01', This can mean that a reference quality factor drop value of 1321 is recorded in a 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 material status packet is defined according to the mode in the specific embodiment. Although the explanation was made separately, regardless of the mode, the foreign substance state packet is the same as the implementation of Figures 13d to 13g. It may be in the form of an embodiment.

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

[0399] Referring to FIG. 13g, the FO Status Packet message 1330 has a length of 2 bytes. The accuracy of the reference quality factor (QF) is 6 bits long. 1331 field, a 2-bit long mode Mode 1332 field and Reference Quality Factor value The QoS Factor Value (QFV) 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, an error tolerance may be 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 increasing or decreasing ratio.

[0401] The accuracy of the standard quality factor 1331 varies depending on the manufacturer (or) and product type of the wireless power receiver. For example, if a wireless power receiver from company A and a wireless power receiver from company B are The receivers are connected to the same wireless power transmitter, and the accuracy of the measured reference quality factor values ​​varies. Therefore, the wireless power transmitter can obtain information about the accuracy of the reference quality factor for each wireless power receiver. It is necessary to obtain the quality required to determine whether or not foreign matter exists, taking into account the accuracy of the standard quality factor. The critical value of the factor can be determined. In addition, for the convenience of the following description, the wireless power transmitter is 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 are as follows: The measured reference quality factor value is 100, the reference quality measured for the wireless power receiver of company B The factor value can 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 for a wireless power receiver from company A is within + / -7%. It can be set higher than + / - 10%. 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. Depending on the part, the quality factor may be measured lower than other finished products even when there are no foreign substances. This allows the finished product to be placed in the charging area together with other foreign substances. The difference in quality factor values ​​may be small compared to the actual 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 it is being recorded. Referring to the plane code 1334, if the value of the mode 1332 field is binary '01', This can 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 flowchart illustrating a method for detecting FOD according to another embodiment of the present invention. be.

[0407] Referring to FIG. 14, during 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 binary "0 1”.

[0408] The second reference quality factor value is measured at multiple points on the charging area of ​​a specified wireless power transmitter. The value having the 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 around the machine, the transmitting coil (Primary Coil) and receiving coil The first quality factor measured at the central position where the (Secondary Coil) is well aligned value and the presence of FO around the wireless power receiver, without rotating the wireless power receiver from the center A fixed distance offset (for example, + / - 5 mm in the x and y directions) The minimum value of the second quality factor values ​​measured while moving in a direction (including but not limited to) is determined. wherein the second quality factor values ​​are measured at at least four different locations. The quality factor value may include:

[0410] The wireless power transmitter 1420 receives the second reference quality factor value and the wireless power transmitter 1420 FO detection based on pre-stored design factors corresponding to For the sake of convenience, the following description will be given with reference to the structure. The second reference quality factor value corrected based on the composition factor is used as the corrected quality factor critical value (Q_thres hold_correct).

[0411] The second reference quality factor value is a specified specific wireless power transmitter (hereinafter referred to as the test wireless power transmitter The quality factor is determined based on the measured quality factor values ​​on the and a wireless power transmitter manufactured for commercial use (hereinafter, for the sake of convenience, a commercial wireless power transmitter is referred to as a The test equipment (hereafter referred to as 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 both 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 needs to be corrected accordingly.

[0412] For example, the component may be the power class (Power Class) 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 The measurement error of the quality factor value for the test wireless power transmitter is obtained, but is not limited to this. 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.) It can be compared to see if it is greater than or equal to (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 to do so.

[0415] As a result of the comparison, the current quality factor value (Q_current) is equal to the corrected quality factor critical value (Q_thr eshod_correct), the wireless power transmitter 1420 It can determine that FO is not detected and transmit an ACK response to the wireless power receiver 1410. At this time, the state of the wireless power transmitter 1420 changes 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 critical value (Q_threshod_correct), the wireless power transmitter 1420 determines that FO is detected and transmits a NAK response to the wireless power receiver 1410. At this time, the state of the wireless power transmitter 1420 changes from the negotiation stage to the You can move on to the selection stage.

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

[0418] Referring to FIG. 15, during the negotiation phase, the wireless power receiver 1510 receives a reference quality factor value (Ref erence Quality Factor Value, Q_reference) and transmit the first and second FOD status packets including the 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 value of FO 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 under 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 measured quality factor value in the state where the temperature is around 100°C. The first and second reference quality factor values ​​are obtained by measuring the number of wireless power transmitters on the charging area of ​​a specific test wireless power transmitter. The value having the minimum value among the quality factor values ​​measured at points 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 ate, Q_threshold_rate) can be determined (S1503).

[0423] Here, the quality factor critical rate (Q_threshold_rate) is the first standard quality factor. The difference between the child value (RQF_NO_FO) and the second reference quality factor value (RQF_FO) is used 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 the 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). The 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 determined immediately before the (re)negotiation stage 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 to see if it is smaller than the quality factor critical rate (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 The wireless power transmitter 1520 can transmit a NAK response (S1507). The state 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 threshold value can be determined as follows.

[0431] The received Reference Quality Factor V The quality factor measurement error range (e.g. ±10% (0.61 * reference quality factor value) or Accuracy of Quality Factor Value (Figure 19g) The transmitter characteristics (transmitter type (design), manufacturer, product or measurement error, etc.) are taken into consideration when determining the 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 calculate the quality factor from the quality factor table 1 based on the received FO status packet. 600 can be updated. As an example, the quality factor table 1600 can be 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_correct t) 1605) fields.

[0434] Here, the receiver identifier 1601 is a manufacturer code (ma) obtained in the identification and configuration step. manufacturer 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 can be configured as a manufacturer code, a basic device identifier, or the like. It can 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 can be recorded corresponding to the Negotiation is performed when charging is successfully completed for the wireless power receiver corresponding to the receiver identifier 1601. If a steady state transition to the power transmission state is made in the negotiation stage, the wireless power transmitter The quality factor values ​​measured at 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 stage, it sends the FOD status packet. 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 must be configured to detect FO during the initial negotiation with the corresponding wireless power receiver. The calculated corrected quality factor critical value (Q_threshold_correct) is used as the quality factor test value. It can also be recorded on a 1600 cable.

[0438] The wireless power transmitter corresponds to the receiver identifier recorded in the quality factor table 1600 thereafter. 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. 13f. The quality factor drop value 1321 and the reference quality factor accuracy 1331 described above in FIG. 13d are It may further comprise at least one of:

[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 or equipped with 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 can be received, where the reference quality factor value is the Reference quality factor value when not in the area (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 in the negotiation phase, one FOD status packet or multiple FOD status packets may be included. This can be received via the FOD status packet.

[0444] The decision unit 1720 decides a threshold value to be used when detecting FO based on the received reference quality factor value. For example, the critical value used in FO detection can be the second reference quality factor value (R QF_FO), but this is only one example and other embodiments of the present invention may be 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 can also be determined as a second reference quality factor value corrected for the above.

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

[0446] In the first embodiment, the quality factor critical rate (Q_threshold_rate) is the first standard product. 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 product. The quality factor value (RQF_FO) is determined by dividing the first reference quality factor value (RQF_NO_FO). The first standard quality factor value (RQF_NO_FO) is 80, the second standard quality factor value (RQF_NO_FO) is 80, and the 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 FO are first and second reference qualities. The factor value is calculated by applying a predetermined configuration factor corresponding to the wireless power transmitter. Corrected quality factor critical ratio calculated based on the first corrected reference quality factor and the second corrected reference quality factor It can also be determined as (Q_threshold_rate_correct).

[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 measures the current quality factor value (Q_current) during the negotiation stage. 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 e_rate) can be calculated, where the quality factor decrease rate (Q_decrease 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 Based on the quasi-quality factor value (RQF_NO_FO), the current quality factor ratio (Q_current t_rate) can be calculated, where the current quality factor ratio (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 threshold value determined by the measurement unit 1730. By comparing the measured or calculated values ​​with the do.

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

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

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

[0457] As yet another example, the detector 1740 may detect a quality factor decrease ratio (Q_decrease_ The corrected quality factor calculated based on the rate and the configuration factors 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 V alue) quality factor measurement error range (ex. ±10% (0.61*referenceQ- FactorValue), or Quality Factor Value Accuracy (Accuracy of Qual ity Factor Value (Figure 11d)) and transmitter characteristics (transmitter type (design) The accuracy can be determined by taking into consideration the type of product, manufacturer, product or measurement error, etc.

[0460] The control unit 1750 can control the overall operation and input / output of the FO detection device 1700. For example, the control unit 1750 may detect that the FO has not been detected by the detection unit 1740. If so, 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, and the power transmission unit 1760 is shut off. It can be controlled as follows.

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

[0462] The FO detection device 1700 according to another embodiment of the present invention detects the following 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 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, during 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 801). At this time, the Mode value of the FOD status packet is set to binary "01". It can be set as, but is not limited to,

[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 is determined as the minimum value of the quality factor values ​​measured at multiple points in the area. It can be maintained 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] In one example, the wireless power transmitter 1820 subtracts 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 to this. A predetermined quality factor critical value generating function is defined, where the reference quality factor value and the reference quality factor drop value are input variables. It can also be used to determine the quality factor critical value.

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

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

[0470] As a result of the comparison, the current quality factor value (Q_current) is equal to the quality factor threshold value (Q_thres hod), the wireless power transmitter 1820 determines that FO is not detected. The wireless power receiver 1810 determines that the power supply 1800 is connected to the power supply 1802 and transmits an ACK response to the power supply 1802 (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 comparison of the 1804 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 1820 detects that the FO The wireless power receiver 1810 determines that the NAK response has been received and transmits a NAK response to the wireless power receiver 1810 (S18 06). At this time, the state of the wireless power transmitter 1820 transitions from the negotiation stage to the selection stage. 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, during the negotiation phase, the wireless power receiver 1910 determines 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”. It can be, but is not limited to,

[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 one 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 value obtained by subtracting the production and measurement errors can be determined as the quality factor critical value, but is not limited to this. Another example is a predetermined quality factor where the reference quality factor accuracy and the reference quality factor value are input variables. The quality factor critical value can 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 Whether the quality factor value (Q_current) is equal to the quality factor critical value (Q_threshod) It is possible to compare whether the value is larger than the other value (S1903 to S1904).

[0478] According to one 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 the quality factor threshold value (Q_thres hod), the wireless power transmitter 1920 determines that FO is 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_threshod) is less than the threshold value, the wireless power transmitter 1920 detects that the FO The wireless power receiver 1910 determines that the NAK response has been received and transmits a NAK response to the wireless power receiver 1910 (S19 06). At this time, the state of the wireless power transmitter 1920 transitions from the negotiation stage to the selection stage. 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 the reference quality factor value, the reference quality factor accuracy, the reference quality factor The critical value of the quality factor may be determined using at least one of the following: the product drop value, the production error, and the measurement error. can.

[0482] As an 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. You can also do this.

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

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

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

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

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

[0488] The wireless power transmitter is configured to transmit a second power signal to a second frequency greater than the first frequency within the operating frequency band. The quality factor value can be measured (S2003).

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

[0490] In one embodiment, the first frequency is the operating frequency (O) for the maximum quality factor value of 12 to 11 g. 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 to for this purpose is determined to be 100 kHz, and the reference quality factor value is measured and transmitted / received. Therefore, 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-aligned state.

[0493] As a result of the comparison in step 2005, if the second quality factor value is greater than the first quality factor value, 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 indicates that the second quality factor value is greater than the first quality factor value. If the detection signal is large enough, it may only indicate the presence of foreign matter in the charging area.

[0495] In the presence of foreign matter, the second frequency is higher than the misaligned state. The quality factor value corresponding to the first frequency appears to be larger than the quality factor value corresponding to the second frequency. Foreign materials with small impact have similar quality factor values ​​to unaligned ones. It is a quality factor that can be measured when foreign substances that have a relatively large effect are present. The quality factor values ​​are relatively different from the quality factor values ​​measured when misaligned 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 unaligned object has been detected, if power transmission is currently in progress, the power transmission will be interrupted and the and outputting a predetermined alarm signal to indicate that an unregistered wireless power receiver has been placed. This can be done.

[0497] After outputting the alarm signal, the wireless power transmitter waits for a certain period of time before entering the selection stage. The receiver can also be searched. Any foreign objects placed in the charging area can be removed by the user. The wireless power receiver may be repositioned correctly by the user. Taking this time into consideration, the waiting time before proceeding to the selection step can be determined. .

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

[0499] According to yet another embodiment of the present invention, the wireless power transmitter may include: 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 receivers are aligned, you can check whether they are aligned. The line power transmitter may also enter the selection stage.

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

[0501] In another embodiment of the wireless power transmitter, steps 2701 to 2709 are performed in the same manner as in FIG. This can also be performed in the power transmission step 260. In this case, the wireless power transmitter adjusts the operating frequency. While power control using the node is being performed, the quality factor value is measured for each frequency and compared to It is also possible to 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. 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 acquired quality factor peak operating frequency. It is possible to determine whether or not a foreign substance is present. It can be directly compared with the reference peak frequency. The critical frequency is determined by taking into consideration the error of the transmitting coil or design, product, etc. The quality factor peak operating frequency can also be compared to the critical frequency.

[0503] FIG. 21 is a block diagram illustrating the structure of an FO detecting device corresponding to the embodiment of FIG. 20. 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 2111, a The system 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 may be They can be integrated into one module or device. In this case, the same measuring unit The first quality factor value and the second quality factor value 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 store the quality factor peak operating frequency corresponding to the maximum quality factor value in memory. 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 factor 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, 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 may 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 determines whether or not a foreign substance is present in the charging area based on the first quality factor value and the second quality factor value. Alternatively, the quality factor peak operating frequency and wireless power receiving frequency can be determined. The presence of foreign matter in the charging area is determined 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 receivers are placed on the charging area.

[0509] As another example, the detection unit 2930 may detect whether the second quality factor value is greater than the first quality factor value by a predetermined reference value. If it is larger than this, there may be foreign matter 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 the second quality factor value. The difference between the second quality factor value and the first quality factor value is smaller than the specified reference value. If not, it can be determined that the aligned wireless power receivers are 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 charge value, it is possible that a foreign object has been placed on the charging area or that the wireless 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 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

[0513] On the other hand, the detection unit 2130 detects whether the calculated change ratio is smaller than 0 or a predetermined negative number. If the value is equal to or less than the second critical value, 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. and a predetermined alarm signal to indicate the presence of an unaligned wireless power receiver. The alarm can be output via the alarm means provided. buzzer), LED light, vibration, LCD display, etc. This is not limited to:

[0516] According to one embodiment, the control unit 2150 may be configured to detect a foreign object or a misaligned wireless power receiver. If it is determined that the power has been transmitted, the power transmission will be stopped if it is currently being transmitted. The power transmission unit 2160 is controlled to prevent a foreign object or an unaligned wireless power receiver from being placed. The alarm unit 2140 is controlled so that a predetermined alarm signal indicating that the alarm has been received is output. It is possible.

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

[0518] If foreign objects placed in the charging area are removed by the user or if the wireless 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 quality factor values ​​for the number and the second frequency, 2110, 2120, and compare the measured first and second quality factor values ​​to determine the charging area. It is also possible to check whether the foreign substance placed in the In this case, the control unit 2150 can enter a selection step.

[0520] According to another embodiment of the present invention, the control unit 2150 may select the 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 correctly. If the wireless power receivers are correctly aligned as a result of the check, the control unit 2150 proceeds to the selection step. You can also enter.

[0521] In yet another embodiment, the foreign substance detection step is a selection step, i.e., performed 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 yet 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 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 flowchart illustrating a method for detecting FO based on a quality factor value in another embodiment of the present invention. -Chart.

[0524] Referring to FIG. 22, the wireless power transmitter operates in a predetermined operating frequency band at a certain frequency. The frequency can be divided into 1st to Nth frequencies having intervals of several frequencies (S2201). The operating frequency band is broadly divided into a lower frequency band, an intermediate frequency band, and an upper frequency band. Here, the size of each frequency band can be changed according to the user's settings. As an example, if the operating frequency band is 10 It is between 0KHz and 210KHz and is used to distinguish specific frequencies within the operating frequency band. If the frequency interval for the 10KHz band is set to 10kHz, the corresponding operating frequency band will be 1st to 12th frequencies. Here, the first to third frequencies are the lower limit frequency band (100KH z~130KHz, and the 4th to 9th frequencies are in the intermediate frequency band (130KHz~180KHz ), and the 10th to 12th frequencies are divided into the upper frequency band (180KHz to 210KHz). This is merely an example, and the setting and configuration of the wireless power transmitter, 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 operates for the N-K+1th to Nth frequencies included 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 to Nth frequencies included in the upper limit frequency band. The 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 It can be determined that the line power receiver is installed (S2209). The coupling coefficient between the primary coil and the 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 detect that a foreign object or misaligned wireless power receiver has been placed on the charging area. This can be done (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 indicating that the operation has been completed can be output (S2213).

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

[0532] In another embodiment of the wireless power transmitter, steps 2201 to 2213 are performed in the same manner as in FIG. This can also be performed in the power transmission step 260. In this case, the wireless power transmitter operates at an operating frequency 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 using the measured quality factor values ​​for each frequency. After calculating the average value of the child and the average value of the quality factor of the lower frequency band, they are 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 calculated. The presence or absence of foreign matter is determined by comparing the magnitude of the average quality factor (a2) of the band. 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 due to frequency changes, but also checks whether the average quality factor The increase / decrease amount is based on the amount of foreign matter or misaligned wireless power receivers in the charging area. For example, if the value obtained by subtracting a1 from a2 is negative, If the absolute value of the difference between a2 and a1 exceeds a predetermined threshold value, the wireless power transmitter determine 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 illustrating the structure of an FO detecting device corresponding to the embodiment of FIG. 22. be.

[0535] Referring to FIG. 23, an FO detection device 2300 includes an operating frequency division unit 2310, a quality factor Measurement unit 2320, average calculation unit 2330, detection unit 2340, alarm unit 2350 and 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 frequency band can be divided into a lower frequency band, a middle frequency band, and an upper frequency band. The number of frequencies to be measured included in the upper and lower frequency bands is predefined and a predetermined recording area is used. The operating frequency band, frequency interval, lower / upper frequency band, The number of frequencies to be measured and other information included in the wireless power transmitter are determined by the user interface. and (and) an external device that interfaces with 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 included 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 particles on the charging area based on a1 and a2. and transmits the detection result to the control unit 2360. For example, if the value obtained by subtracting a2 from a1 is a positive number, the detection unit 2340 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 a negative number, 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 the average quality factor due to frequency variations within the operating frequency band. Consider not only whether the value increases or decreases, but also the amount of 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 predetermined critical value, the wireless power transmitter detects foreign matter or misaligned wireless devices. 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. and 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. It can include buzzer, LED light, vibration, LCD display, etc. This is not limited to this.

[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 placed on the charging area. In this case, the quality factor value measured by the wireless power transmitter is within the operating frequency band (100KHz~210kHz). kHz) increases as the frequency increases. For reference, if the first receiver and the foreign substance 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 frequency is The quality factor value measured at a frequency of 100KHz is 44, and the measured value 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. The quality factor measured at an operating frequency of 210 KHz was found to be 30.65. Here, FO4 refers to the standard foreign material defined in the WPC standard.

[0545] The experimental results shown in Figure 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 an increasing value.

[0546] Figure 24b is for a second receiver made by a different manufacturer than the first receiver in Figure 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~210kHz). 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 by the 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 KHz The quality factor measured in KHz is 31.1. When the transmitter and the foreign substance FO4 are placed, the quality measured at an operating frequency of 100KHz The factor value was 24.9, and 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, similar to those in FIG. 24a, show that the charging area When wireless power receivers are arranged in an aligned fashion, the However, if a foreign object is placed in the charging area, the quality factor value will decrease. It shows that the quality factor value increases as the frequency increases.

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

[0551] Drawing numbers 2431 and 2432 in Figure 24c are measured for a dime and FO4, respectively. The change pattern of the quality factor values ​​determined is shown in FIG. ,When 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 measured in several bands is greater than the In order to minimize the occurrence of incorrect decisions, the above-described steps are performed as described in FIGS. 22 and 23. As shown in the figure, the average quality factor calculated for each of the lower and upper frequency bands is Based on this, it is possible to determine whether or not a foreign substance is present.

[0553] Figure 24d shows a third receiver sold by a different manufacturer than the first and second receivers mentioned 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 as the frequency increases, but as shown in the drawings 2442 and 2443, If a foreign object, such as FO4 or a 10-cent copper coin, is placed in the charging area, It shows 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 shown below.

[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 module is placed in the operating frequency band, the quality factor value increases as the frequency increases. 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 frequency within the operating frequency band increases. Therefore, it can be seen that the quality factor value decreases. However, referring to the reference number 2453, Measured with a standard wireless power receiving 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. It is clear that this will become more difficult.

[0557] Figure 25 shows the quality factor values ​​depending on the placement of a wireless power receiver and foreign objects in the charging area of ​​a wireless power transmitter. FIG. 10 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 wireless power receiver is not placed in the charging area. 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 whether or not a foreign substance is present. It is possible to determine nothing.

[0560] FIG. 26 shows 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 the 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 values ​​at which the quality factor values ​​are measured may be predetermined. The values ​​are selected within a defined operating frequency range and have a fixed frequency interval. For example, the operating frequency range of the foreign substance 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 ​​specified are 100KHz, 130KHz, 160KHz, 190KHz and It can be 220KHz.

[0562] The foreign material detection device determines whether a foreign material 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, the foreign material detection device may have an increased quality factor value as the operating frequency increases. If the foreign substance is detected, it can be determined that a foreign substance is present in the charging area. If the quality factor value decreases as the operating frequency increases, it means that 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 calculates the amount of 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 to this). If the voltage exceeds the specified value, it can be determined that a foreign substance exists in the charging area. The adjacent operating frequencies are the two closest operating frequencies at which the quality factor 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 predetermined first reference value, it is determined that a foreign substance is present in the charging area. On the other hand, if the average of the calculated slopes is equal to or less than a predetermined 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 completes the determination of whether or not a foreign substance exists, it proceeds to step ping 2620. can enter.

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

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

[0569] Once the identification and configuration of the wireless power receiver is complete, the foreign substance detection device proceeds to negotiation step 264. 0 and sends a foreign object detection status packet (FOD Stat) from the identified wireless power receiver. In this case, the foreign substance detection state is The packet may include a reference quality factor value.

[0570] The foreign substance detection device detects the wireless power receiving device identified based on the result of the judgment in step 2602. A NAK response signal or an ACK response signal can be transmitted to the receiver (S2604). At this time, the foreign substance detection device determines whether a foreign substance is present based on the received foreign substance detection status packet. It is not necessary to determine the critical value (or critical range) for determining the value of the threshold value. If the result of the test indicates that a foreign substance is present, the foreign substance detection device sends a NAK response signal to the identified radio After transmitting the signal to the receiver, the process proceeds to selection step 2610. The power supply will interrupt power transmission and issue a predetermined 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 substance detection device determines that no foreign substance is present in step 2602, It is also possible to transition to the power transmission stage 2650 via the correction stage 250 of FIG.

[0572] The foreign substance detection device enters 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 foreign substance detection 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 substance 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 transitioning to the selection step 2610 due to the detection of a foreign substance, If the detected foreign matter is not removed during this time, the foreign matter detection device A predetermined warning alarm can be output to indicate that the information has not been removed.

[0574] The foreign substance detection device according to another embodiment of the present invention corresponds to the determination result of step 2601. Predetermined foreign matter presence information including foreign matter status information (FO Status Information) Presence Status Packet (FO Presence Status Packet) is sent to the corresponding wireless For example, if the foreign substance status information is '0', If it is '1', it means that no foreign matter was detected, and if it is '1', it means that a foreign matter 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 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 2701 field is 6 bits long, and the second mode ( Mode) 2702 field and a 1-byte long reference quality factor value (Reference 3) Quality Factor Value (QFV) field. 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 power of the wireless power receiver in the 2703 field when it is 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 of the corresponding wireless power receiver is turned off. The operating frequency at which the quality factor measured in the condition where the temperature is 5% lower than the reference quality factor value is 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 can 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 a value can be anywhere between 120KHz and 130KHz.

[0579] In the example of FIG. 27, the operation having a quality factor value 5% lower than the reference quality factor value. It is assumed that a value corresponding to the frequency is recorded in the first data 2701 field. However, this is only 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 shows 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, if an object is detected in selection step 2810, the foreign substance detection device 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 to this and may be more than that. The operating frequency at which the factor value is measured is a value selected within a predefined operating frequency range. , can be selected to have a fixed frequency interval, but is not limited to this. For example, the operating frequency of the foreign substance detection device may be selected arbitrarily within the operating frequency range. The frequency range can be from 100KHz to 220KHz. At this time, the lower limit frequency is 100K. Hz and the number of operating frequencies to be measured is 7, the operating quality factor value is Frequency values ​​are 100KHz, 120KHz, 140KHz, 160KHz, 180KHz, It can be 200KHz and 220KHz.

[0582] The foreign substance 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 matter detection device pings the wireless power receiver with a predetermined voltage to identify the wireless power receiver. A force signal, for example a digital ping, may be transmitted periodically.

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

[0586] Once the identification and configuration of the wireless power receiver is complete, the foreign substance detection device proceeds to negotiation step 284. 0 and sends a foreign object detection status packet (FOD Stat) from the identified wireless power receiver. In this case, the foreign substance detection state is The packet contains an operating frequency (hereinafter referred to as For ease of explanation, information about the critical frequencies (referred to as 'critical frequencies') may be included.

[0587] The foreign substance detection device measures the quality factor corresponding to the lower limit frequency measured in the 2801 step mentioned above. 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 largest value among the quality factor values ​​measured at a larger operating frequency may be .

[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 substance detection device is in the charging area. It can be determined that no foreign substance is present.

[0589] In another embodiment, the foreign substance detection device has a quality factor for each operating frequency measured in 2801 steps. Based on the values, the quality factor values ​​corresponding to the critical frequencies can be determined (or estimated). For example, among the multiple operating frequencies used to measure the quality factor value in step 2801, If the same frequency as the wave number is included, the quality factor value measured at the corresponding operating frequency is However, the quality factor value measured at step 2801 is If the multiple operating frequencies do not include the same frequency as the critical frequency, the critical frequency based on at least one quality factor value measured at the nearest operating 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 This is not limited to this.

[0590] The foreign substance detection device detects the wireless power receiving device identified based on the result of the judgment in step 2803. A NAK response signal or an ACK response signal can be transmitted to the receiver (S2804). At this time, the foreign substance detection device determines whether a foreign substance is present based on the received foreign substance detection status packet. It is not necessary to determine the critical value (or critical range) for determining the above-mentioned step 2803. If the result of the test indicates that a foreign substance is present, the foreign substance detection device sends a NAK response signal to the identified radio After transmitting the signal to the receiver, the process proceeds to selection step 2810. The power supply will interrupt power transmission and issue a predetermined warning alarm indicating that a foreign object has been detected. It can be output.

[0591] For example, if the result of the determination in step 2802 indicates 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 substance detection device determines that no foreign substance is present in step 2803, It is also possible to transition to the power transmission stage 2850 via the correction stage 250 of FIG.

[0592] The foreign substance detection device enters the power transmission step 2850 and wirelessly charges 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 foreign substance detection 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 substance 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 substance detected by the foreign substance detection device is not removed, the foreign substance detection device A predetermined warning alarm may be output indicating that the

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

[0595] FIG. 29 shows 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 foreign substance detection device according to this embodiment, if an object is detected in the selection step 2910, a plurality of motions are selected. The quality factor value of the resonant circuit with respect to the operating frequency can be measured (S2901).

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

[0598] The foreign substance detection device has a frequency response that corresponds to each of the operating frequencies that are equal to or greater than the critical frequency. By comparing the quality factor values, it is possible to determine whether or not foreign matter is present (S2904). As a result, if the quality factor value increases as the operating frequency increases, the foreign substance detection device 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] In accordance with another embodiment of the present invention, if 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 plurality 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 frequency 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 quality of the product while changing the frequency within 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

[0604] Referring to FIG. 30, the FOD status packet message 3000 has a length of 2 bytes. There is a 6-bit long reserved 3001 field, and a 2-bit long mode (Mod e) 3002 field, first data 3003 field and second data field 30 30. In the embodiment of FIG. 30, 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. Although shown as being, this is by way of example only and is not 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 the lower limit frequency. 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-described embodiment is implemented in a program to be executed by a computer. The present invention can be stored in a computer-readable recording medium, and examples of the computer-readable recording medium include These include ROM, RAM, CD-ROM, magnetic tape, floppy disk, and optical data. 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 fashion. And a functional program for implementing the above-mentioned method, The code and code segments are easily inferred by programmers skilled in the art to which the embodiments pertain. It is possible to argue that

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

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

[0610] The foreign substance detection method according to the embodiment uses the quality factor value to perform the detection before the ping stage, the negotiation stage, and the A wireless charging device that detects foreign objects located between wireless power transmitters during the power transmission stage. This is applicable to power systems.

Claims

1. 1. A method for communicating with a wireless power transmitter in a wireless power receiver, comprising: receiving a power signal of a predetermined strength from a wireless power transmitter; transmitting a data packet to the wireless power transmitter, the data packet including a reference peak frequency of the wireless power receiver pre-assigned to the wireless power receiver and a mode bit field indicating whether the reference peak frequency is included; and receiving a response from the wireless power transmitter indicating whether or not a foreign object is present in the charging area; the response is determined by the wireless power transmitter by comparing a peak frequency and a critical frequency of the power signal; The method, wherein the critical frequency is determined by the wireless power transmitter based on a reference peak frequency of the wireless power receiver and a design factor (Design_factor) of the wireless power transmitter.

2. The method of claim 1 , wherein when the mode bit field indicates that the data packet includes the reference peak frequency, the data packet further includes a reference peak frequency value of a reference peak frequency of the wireless power receiver.

3. The method of claim 1 or claim 2, wherein the reference peak frequency is measured with the wireless power receiver turned off.

4. The method according to claim 1 or 2, wherein the reference peak frequency is a peak frequency in the absence of a foreign object.

5. the reference peak frequency is pre-assigned to the wireless power receiver based on a reference wireless power transmitter; The method of claim 1 or 2, wherein the critical frequency is determined by taking into consideration at least one of a coil design and a circuit characteristic that are different from those of the reference wireless power transmitter.

6. The method of any one of claims 1 to 5, wherein the response indicates the presence of the foreign object in the charging area when the peak frequency of the power signal is greater than the critical frequency.

7. The method of any one of claims 1 to 6, wherein the response indicates that the foreign object is not present in the charging area when the peak frequency of the power signal is less than or equal to the critical frequency.

8. The method according to any one of claims 1 to 7, wherein the peak frequency of the power signal is shifted from the reference peak frequency when the foreign object is present in the charging area.

9. The method of claim 1 or 2, wherein the reference peak frequency comprises a frequency corresponding to a Q value within an operating frequency range of the wireless power transmitter.

10. The method according to any one of claims 1 to 9, further comprising: upon receiving a response indicating that the foreign object is not present in the charging area, continuing to receive wireless power transmitted from the wireless power transmitter.

11. A wireless power receiver in communication with a wireless power transmitter, receiving a power signal of a predetermined strength from a wireless power transmitter; transmitting a data packet to the wireless power transmitter, the data packet including a reference peak frequency of the wireless power receiver pre-assigned to the wireless power receiver and a mode bit field indicating whether the reference peak frequency is included; a controller configured to receive a response from the wireless power transmitter indicating whether or not a foreign object is present in the charging area; the response is determined by the wireless power transmitter by comparing a peak frequency and a critical frequency of the power signal; The wireless power receiver, wherein the critical frequency is determined by the wireless power transmitter based on a reference peak frequency of the wireless power receiver and a design factor (Design_factor) of the wireless power transmitter.

12. The wireless power receiver of claim 11 , wherein when the mode bit field indicates that the data packet includes the reference peak frequency, the data packet further includes a reference peak frequency value of a reference peak frequency of the wireless power receiver.

13. The wireless power receiver according to claim 11 or 12, wherein the reference peak frequency is measured in a state where the wireless power receiver is turned off.

14. The wireless power receiver according to claim 11 or 12, wherein the reference peak frequency is a peak frequency in a state where no foreign object is present.

15. the reference peak frequency is pre-assigned to the wireless power receiver based on a reference wireless power transmitter; The wireless power receiver according to claim 11 or 12, wherein the critical frequency is determined in consideration of at least one of a coil design and a circuit characteristic that are different from those of the reference wireless power transmitter.

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