Method and apparatus for detecting foreign objects

Abstract

A method for detecting a foreign object in a wireless power transmitter that wirelessly transmits power to a wireless power receiver through a resonance circuit included in the wireless power transmitter, according to one embodiment of the present invention, can include measuring a strength of power transferred through the resonance circuit in a power transmission step, receiving a feedback packet including information on a received power strength from the wireless power receiver, determining whether the information on the received power strength is normal, correcting the received power strength by applying a predetermined offset to the received power strength when it is determined that the received power strength corresponding to the information on the received power strength is abnormal, calculating a path loss based on the measured transmitted power strength and the corrected received power strength, and detecting a foreign object by comparing the calculated path loss with a path loss threshold.

Description

[0001] This application is a divisional application of Chinese patent application filed on July 8, 2019, with application number 201780082669.1 and entitled "Method and Apparatus for Detecting Foreign Objects". The international filing date of the parent application is November 14, 2017, and the international application number is PCT / KR2017 / 012877. Technical Field

[0002] The implementation methods relate to wireless power transmission technology, and more specifically, to a foreign object detection method and apparatus capable of detecting foreign objects present in the wireless power transmission path. Background Technology

[0003] In recent years, with the rapid development of information and communication technologies, a society based on ubiquitous information and communication technologies is developing.

[0004] To enable ubiquitous connectivity for information and communication devices, sensors equipped with computer chips capable of communication should be installed in all public facilities. Therefore, providing power to such devices or sensors presents a new challenge. Furthermore, with the rapid increase in the types of mobile devices such as music players (e.g., Bluetooth phones or iPods) and mobile phones, users need to spend more time and effort charging their batteries. Wireless power transmission technology has recently attracted attention as a solution to these problems.

[0005] Wireless power transfer, or wireless energy transfer, refers to the technology of wirelessly transmitting electrical energy from a transmitter to a receiver using the principle of magnetic induction. In the 19th century, electric motors or transformers utilizing the principle of electromagnetic induction were already in use, and since then, attempts have been made to transmit electrical energy by radiating electromagnetic waves such as high frequencies, microwaves, and lasers. The principle of electromagnetic induction is used to charge commonly used electric toothbrushes or some wireless shavers.

[0006] To date, wireless power transfer methods can be broadly categorized into magnetic induction methods, electromagnetic resonance methods, and short-wavelength radio frequency (RF) transfer methods.

[0007] Magnetic induction utilizes the following phenomenon and has been rapidly commercialized in small devices such as mobile phones: when two coils are brought close together, and a current is applied to one coil, a magnetic flux is generated, inducing an electromotive force in the other coil. Magnetic induction can transmit power up to hundreds of kilowatts (kW) and is highly efficient. However, since the maximum transmission distance is 1 centimeter (cm) or less, the device to be charged should be near a charger or the floor.

[0008] Electromagnetic resonance uses electric or magnetic fields instead of electromagnetic waves or electric current. It is less affected by electromagnetic waves, thus contributing to the safety of other electronic devices or the human body. However, it can be used over limited distances and spaces, and its energy transfer efficiency is slightly lower.

[0009] Shortwave wireless power transmission (RF transmission method for short) utilizes the fact that energy can be directly transmitted and received in the form of radio waves. This technology is an RF wireless power transmission method that uses a rectifier antenna. A rectifier antenna is a combination of an antenna and a rectifier, and refers to a component used to directly convert RF power into DC power. In other words, the RF method is a technology used to convert AC radio waves into DC. Recently, with the improvement in the efficiency of the RF method, active research has been conducted on its commercialization.

[0010] Wireless power transmission technology can be used not only in mobile-related industries, but also in a variety of industries such as IT, railways and home appliances.

[0011] If a foreign object (FO) that is not a wireless power receiver is present in the wireless charging area, electromagnetic signals that can be received from the wireless power transmitter can be generated in the foreign object. For example, FO can include coins, clips, pins, and ballpoint pens.

[0012] If an external foil (FO) exists between the wireless power receiver and the wireless power transmitter, wireless charging efficiency may be significantly reduced, and the temperatures of both the receiver and transmitter may rise due to the increased ambient temperature of the FO. If the FO is not removed quickly from the charging area, power may be wasted, and the device may be damaged due to overheating.

[0013] Therefore, accurately detecting the FO on the wireless power transmission path is becoming an important issue in wireless charging technology.

[0014] In current Qi-based wireless charging systems, methods based on path loss of transmitted power and methods based on changes in the quality factor are used as representative methods for detecting foreign objects placed in the charging area.

[0015] However, in the case of foreign object detection methods based on path loss of transmitted power, the wireless power transmitter may fail to detect foreign objects when no information about the accurate received power strength is received from the wireless power receiver.

[0016] If the information regarding the received power intensity is abnormal, the wireless power transmitter may incorrectly determine that the foreign object is in the wireless power transmission path, even though the foreign object is not in the path, thus stopping charging. Summary of the Invention

[0017] Technical issues

[0018] The implementation provides a foreign object detection method and device capable of detecting foreign objects present in a wireless power transmission path.

[0019] The embodiment provides a foreign object detection method and apparatus, which can adaptively adjust the threshold (or threshold range) for foreign object detection based on whether the received power intensity is normal.

[0020] The embodiment provides a foreign object detection method and apparatus that can correct path loss to detect foreign objects when a receiver with abnormally high received power intensity compared to the transmitted power intensity is identified in a wireless power transmitter of a fixed frequency type.

[0021] The embodiment provides a foreign object detection method and apparatus, which prevents power transmission from being stopped even when no foreign object is present by adaptively correcting the received power intensity based on information about whether the received power intensity fed back from the wireless power receiver is normal.

[0022] The embodiment provides a foreign object detection method and apparatus, which can correct the received power strength to detect foreign objects when a receiver with abnormal received power strength compared to the transmitted power strength is identified in a wireless power transmitter of a fixed frequency type.

[0023] The technical problems solved by the implementation methods are not limited to those described above, and other technical problems not described herein will become apparent to those skilled in the art based on the following description.

[0024] Technical solutions

[0025] The implementation provides a method and apparatus for detecting foreign objects.

[0026] A foreign object detection method in a wireless power transmitter, the wireless power transmitter being used to transmit wireless power to a wireless power receiver, according to an embodiment, the method includes: receiving information about the received power strength from the wireless power receiver; determining whether the received power strength is normal; correcting the received power strength when it is determined that the received power strength is abnormal; calculating the path loss of the transmitted power based on the corrected received power strength; and detecting foreign objects based on the calculated path loss.

[0027] Here, information about the received power strength can be included and contained in packets that are periodically fed back during the power transmission phase. These feedback packets are signal strength packets defined in the WPC standard.

[0028] For example, determining whether the received power strength is normal may include: determining a first threshold indicating the maximum received power strength that can be received by the wireless power receiver corresponding to the current transmitted power strength; and determining that the received power strength is abnormal when the received power strength exceeds the first threshold.

[0029] In another example, determining whether the received power strength is normal may include: determining a first threshold range based on the current transmitted power strength and a predefined transmission efficiency to indicate the power level that can be received by the wireless power receiver; and determining that the received power strength is abnormal when the received power strength is outside the first threshold range.

[0030] Additionally, the correction of received power strength may include: determining an offset value based on the current transmitted power strength; and correcting the received power strength by subtracting the offset value from the received power strength.

[0031] In addition, foreign object detection may include: determining a path loss threshold based on the current transmitted power intensity; and determining that a foreign object exists on the wireless power transmission path when the calculated path loss exceeds the path loss threshold.

[0032] The foreign object detection method may also include: receiving a feedback signal for power control during the phase transmission phase; and adjusting the current transmitted power intensity based on the feedback signal.

[0033] The foreign object detection method may further include: measuring a quality factor value after detecting an object but before entering the detection phase; determining a quality factor threshold corresponding to a second wireless power receiver based on the reference quality factor value when a foreign object detection state packet including a reference quality factor value is received during the negotiation phase; and comparing the measured quality factor value with the determined quality factor value to detect the foreign object.

[0034] In another embodiment, a wireless power transmitter for transmitting wireless power to a wireless power receiver includes: a demodulator configured to receive from the wireless power receiver a first packet for power control and a first packet including information about the received power strength; a determination unit configured to determine whether the received power strength is normal; a correction unit configured to correct the received power strength when it is determined that the received power strength is abnormal; and a detector configured to calculate the path loss of the transmitted power based on the corrected received power strength to detect foreign objects.

[0035] Here, the first and second packets can be received periodically, and the wireless power transmitter may also include an adjuster configured to adjust the transmitted power intensity based on the first packet.

[0036] In addition, the first group and the second group can be the control error group and the signal strength group defined in the WPC standard, respectively.

[0037] For example, the determining unit may: determine a first threshold indicating the maximum receive power intensity that can be received by the wireless power receiver based on the current transmit power intensity adjusted by the regulator; and determine that the receive power intensity is abnormal when the receive power intensity exceeds the first threshold.

[0038] In another example, the determining unit may: determine a first threshold range indicating the power level that can be received by the wireless power receiver based on the current transmitted power intensity adjusted by the regulator and a predefined transmission efficiency; and determine that the received power intensity is abnormal when the received power intensity is outside the first threshold range.

[0039] The correction unit can determine the offset value based on the current transmitted power strength and correct the received power strength by subtracting the offset value from the received power strength.

[0040] In addition, the detector can: determine a path loss threshold based on the current transmitted power intensity, and determine the presence of a foreign object in the wireless power transmission path when the calculated path loss exceeds the path loss threshold.

[0041] The wireless power transmitter may further include: a measurement unit configured to measure a quality factor value after an object is detected but before entering a detection phase; and a controller configured to determine a quality factor threshold corresponding to a second wireless power receiver based on the reference quality factor value when a foreign object detection state packet including a reference quality factor value is received during a negotiation phase, and to compare the measured quality factor value with the determined quality factor value to detect a foreign object.

[0042] In another embodiment, a foreign object detection method is provided in a wireless power transmitter for wirelessly transmitting power to a wireless power receiver using a resonant circuit disposed in the wireless power transmitter. The method includes: measuring the intensity of power transmitted through the resonant circuit during a power transmission phase; receiving a feedback packet including information about the received power intensity from the wireless power receiver; determining whether the information about the received power intensity is normal; if the received power intensity is determined to be abnormal, applying a predetermined offset to the received power intensity corresponding to the information about the received power intensity to correct the received power intensity; calculating a path loss based on the measured transmitted power intensity and the corrected received power intensity; and comparing the calculated path loss with a path loss threshold to detect a foreign object.

[0043] Here, information about the received power strength can be signal strength packets defined in the Qi standard that are periodically received during the power transmission phase.

[0044] For example, determining whether information about received power strength is normal may include: calculating the received power strength based on the information about received power strength; determining a threshold indicating the minimum received power strength that can be received by a wireless power receiver corresponding to the measured transmitted power strength; and determining that the information about received power strength is abnormal when the calculated received power strength is less than the threshold.

[0045] In another example, determining whether the information about the received power strength is normal may include: calculating the received power strength based on the information about the received power strength; calculating the ratio of the calculated received power strength to the measured transmitted power; and determining that the information about the received power strength is abnormal when the calculated ratio is less than the pre-measured maximum path loss ratio corresponding to the wireless power transmitter.

[0046] In addition, foreign object detection methods also include setting a charging mode.

[0047] Determining whether the information regarding the received power intensity is normal may include: calculating the received power intensity based on the information regarding the received power intensity; determining the received power intensity threshold corresponding to the set charging mode; and determining that the information regarding the received power intensity is abnormal when the calculated received power intensity is less than the received power intensity threshold.

[0048] Additionally, when the charging mode is set to fast charging mode, the correction of the received power intensity may include: determining the offset corresponding to the set charging mode, and adding the determined offset to the received power intensity to correct the received power intensity.

[0049] In addition, foreign object detection may include: determining a path loss threshold based on the set charging mode; and determining whether there is a foreign object in the wireless power transmission path when the calculated path loss exceeds the path loss threshold.

[0050] In addition, the foreign object detection method may also include: detecting foreign objects based on the quality factor value in the negotiation phase, and when a foreign object is detected in at least one of the negotiation phase or the power transmission phase, it can be finally determined that a foreign object has been detected.

[0051] In another embodiment, a foreign object detection method in a wireless power transmitter, the wireless power transmitter being used to wirelessly transmit power to a wireless power receiver using a resonant circuit disposed in the wireless power transmitter, the method comprising: entering a power transmission phase to initiate a path loss-based foreign object detection procedure if a foreign object detection procedure based on a quality factor value in a negotiation phase has not been executed; determining whether the information regarding the received power strength is normal upon receiving a feedback packet including information regarding the received power strength; and terminating the initiated path loss-based foreign object detection procedure and executing a quality factor-based foreign object detection procedure if it is determined that the information regarding the received power strength is abnormal.

[0052] In another embodiment, a wireless power transmitter for transmitting wireless power to a wireless power receiver includes: a resonant circuit configured to wirelessly transmit a power signal; a measurement unit configured to measure the strength of the transmitted power signal; a demodulator configured to receive a feedback packet including information about the received power strength; and a controller configured to determine whether the information about the received power strength is normal. When it is determined that the information about the received power strength is abnormal, the controller applies a predetermined offset to the received power strength corresponding to the information about the received power strength to correct the received power strength, and calculates path loss based on the measured power signal strength and the corrected received power strength to detect foreign objects.

[0053] Here, information about the received power strength can be signal strength packets defined in the Qi standard that are periodically received during the power transmission phase.

[0054] For example, the controller may: calculate the received power strength based on information about the received power strength; determine a threshold indicating the minimum received power strength that can be received by the wireless power receiver corresponding to the measured transmitted power strength; and determine that the information about the received power strength is abnormal when the calculated received power strength is less than the threshold.

[0055] In another example, the controller may: calculate the received power strength based on information about the received power strength; calculate the ratio of the calculated received power strength to the measured transmitted power; and determine that the information about the received power strength is abnormal when the calculated ratio is less than the pre-measured maximum path loss ratio corresponding to the wireless power transmitter.

[0056] In another example, the controller may: set a charging mode; calculate the received power intensity based on information about the received power intensity; determine a received power intensity threshold corresponding to the set charging mode; and determine that the information about the received power intensity is abnormal when the calculated received power intensity is less than the received power intensity threshold.

[0057] Additionally, when the charging mode is set to fast charging mode, the controller can determine the offset corresponding to the set charging mode and add the determined offset to the received power intensity to correct the received power intensity.

[0058] Additionally, the controller can: determine a path loss threshold based on the set charging mode, and determine whether there are foreign objects in the wireless power transmission path when the calculated path loss exceeds the path loss threshold.

[0059] In addition, the controller can also execute a program for detecting foreign objects based on the quality factor value in the negotiation phase, and when a foreign object is detected in at least one of the negotiation phase or the power transmission phase, it can be finally determined that a foreign object has been detected.

[0060] In another embodiment, a computer-readable recording medium may be provided on which a program for performing any of the methods described above is recorded.

[0061] The various aspects of this disclosure are only a part of the preferred embodiments of this disclosure. Based on the detailed description of this disclosure, those skilled in the art can design and understand various embodiments based on the technical features of this disclosure.

[0062] Beneficial effects

[0063] The effects of the method and apparatus according to the implementation method are as follows.

[0064] The implementation method has the advantage of providing a foreign object detection method and device capable of detecting foreign objects present in a wireless power transmission path.

[0065] The implementation method has the advantage of providing a foreign object detection method and device, which can adaptively adjust the threshold (or threshold range) for foreign object detection based on whether the received power intensity is normal.

[0066] The implementation method has the advantage of providing a foreign object detection method and apparatus that can correct path loss to detect foreign objects when a receiver with abnormal received power intensity compared to the transmitted power intensity is identified in a wireless power transmitter of a fixed frequency type.

[0067] The implementation method has the advantage of providing a foreign object detection method and apparatus, which can prevent power transmission from being stopped even when a foreign object is present by adaptively correcting the received power strength based on information about whether the received power strength fed back from the wireless power receiver is normal.

[0068] The implementation method has the advantage of providing a foreign object detection method and apparatus, which can correct the received power strength to detect foreign objects when a receiver with abnormal received power strength compared to the transmitted power strength is identified in a wireless power transmitter of a fixed frequency type.

[0069] The implementation method has the following advantages: minimizing foreign object detection errors and minimizing user inconvenience caused by charging delays.

[0070] The effects of this disclosure are not limited to those described above. Based on the following description of embodiments of this disclosure, those skilled in the art can obtain other effects not described herein. In other words, based on embodiments of this disclosure, those skilled in the art can obtain effects not anticipated by this disclosure. Attached Figure Description

[0071] The accompanying drawings, included to provide a further understanding of this disclosure and incorporated in and constituting a part of this application, illustrate one or more embodiments of this disclosure and, together with the specification, serve to illustrate the principles of this disclosure. In the drawings:

[0072] Figure 1 This is a block diagram illustrating a wireless charging system according to an embodiment;

[0073] Figure 2 This is a block diagram illustrating a wireless charging system according to another embodiment;

[0074] Figure 3 This is a diagram illustrating a procedure for transmitting sensing signals in a wireless charging system according to an embodiment.

[0075] Figure 4 This is a state transition diagram illustrating the wireless power transmission procedure according to the implementation method;

[0076] Figure 5 This is a state transition diagram illustrating a wireless power transmission procedure according to another embodiment;

[0077] Figure 6 This is a block diagram illustrating the structure of a wireless power transmitter according to an embodiment;

[0078] Figure 7 It is shown that... Figure 6 A block diagram showing the structure of a wireless power transmitter and a wireless power receiver that cooperate with each other;

[0079] Figure 8 This is a view illustrating a method for modulating and demodulating wireless power signals according to an embodiment;

[0080] Figure 9This is a view showing the format of the grouping according to the implementation method;

[0081] Figure 10 This is a view showing the types of grouping according to the implementation method;

[0082] Figure 11 This is a view showing the structure of the foreign object detection device according to an embodiment;

[0083] Figure 12 This is a view showing the structure of the foreign object detection status group message;

[0084] Figure 13 This is a state transition diagram illustrating a foreign object detection method in a wireless power transmission device according to an embodiment;

[0085] Figure 14 This is a state transition diagram illustrating a foreign object detection method in a wireless power transmission device according to another embodiment;

[0086] Figure 15 This is a flowchart illustrating a foreign object detection method according to an embodiment;

[0087] Figure 16 This is a block diagram illustrating the configuration of a foreign object detection device according to an embodiment; and

[0088] Figure 17 This is a flowchart illustrating a foreign object detection method according to an embodiment.

[0089] [Best Implementation Method]

[0090] A foreign object detection method in a wireless power transmitter for transmitting wireless power to a wireless power receiver includes: receiving information about the received power strength from the wireless power receiver; determining whether the received power strength is normal; correcting the received power strength when it is determined to be abnormal; calculating the path loss of the transmitted power based on the corrected received power strength; and detecting the foreign object based on the calculated path loss. Detailed Implementation

[0091] In the following, the apparatus and various methods according to embodiments will be described in detail with reference to the accompanying drawings. Generally, suffixes such as “module” or “unit” can be used to refer to elements or components. The use of such suffixes herein is intended only for ease of description and the suffixes themselves are not intended to have any particular meaning or function.

[0092] The suffixes such as “module” or “unit” used in the following description may refer to a software configuration implemented by executing a program loaded on a microprocessor, but are merely examples. Some “modules” and “units” may be implemented in hardware, or may be implemented in a combination of software and hardware configurations. Therefore, “module” and “unit” as used in the following description should not be interpreted as software components only.

[0093] In the following description of the embodiments, it should be understood that when each element is referred to as being formed "above" or "below" another element, it can be formed directly "above" or "below" another element or indirectly between them, with one or more intermediate elements. Furthermore, it should be understood that "above" or "below" an element can indicate the upward and downward directions of the element.

[0094] In the description of the implementation, the signals transmitted between the wireless power transmission device and the wireless power receiving device can be used interchangeably with packets.

[0095] In the description of the embodiments, for ease of description, the device having the function of transmitting wireless power in a wireless charging system can be used interchangeably with wireless power transmitters, wireless power transmission devices, wireless power transmission devices, wireless power transmitters, transmission terminals, transmitters, transmission devices, transmission sides, wireless power transmission devices, wireless power transmitters, etc. The device having the function of receiving wireless power from a wireless power transmission device can be used interchangeably with wireless power receiving devices, wireless power receivers, wireless power receiving devices, wireless power receivers, receiving terminals, receiving sides, receiving devices, receivers, etc.

[0096] The transmitter according to the embodiment can be configured in the form of pads, brackets, access points (APs), small base stations, brackets, ceiling-mounted structures, or wall-mounted structures. One transmitter can transmit power to multiple wireless power receiving devices. For this purpose, the transmitter may include at least one wireless power transmission device. Here, the wireless power transmission device can use various wireless power transmission standards based on electromagnetic induction methods, which perform charging using the principle of electromagnetic induction: generating a magnetic field in the coil at the power transmission end, and inducing a current in the coil at the receiving end by the magnetic field. Here, the wireless power transmission device may include wireless charging technologies using electromagnetic induction methods as defined in the Wireless Power Consortium (WPC) or Qi, and the Power Matters Alliance (PMA), which are wireless charging technology organizations.

[0097] Additionally, the receiver according to the embodiment may include at least one wireless power receiving device and may simultaneously receive wireless power from two or more transmitters. Here, the wireless power receiving device may include wireless charging technology using electromagnetic induction methods as defined in the Wireless Power Consortium (WPC) (or Qi) and the Power Matters Association (PMA), which are organizations for wireless charging technologies.

[0098] The receiver according to the embodiments can be used in small electronic devices such as mobile phones, smartphones, laptops, digital broadcasting terminals, personal digital assistants (PDAs), portable multimedia players (PMPs), navigation systems, MP3 players, electric toothbrushes, electronic tags, lighting devices, remote controls, fishing floats, wearable devices such as smartwatches, etc., but small electronic devices are not limited to these, and the receiver according to the embodiments can be used in any device including wireless power receiving devices according to the embodiments of charging batteries.

[0099] Figure 1 This is a block diagram illustrating a wireless charging system according to an embodiment.

[0100] Reference Figure 1 A wireless charging system generally includes: a wireless power transmission terminal 10 for wirelessly transmitting power, a wireless power receiver 20 for receiving the transmitted power, and an electronic device 20 for receiving the received power.

[0101] For example, the wireless power transmitter 10 and the wireless power receiver 20 can perform in-band communication, in which information is exchanged using a frequency band that is the same as the operating frequency used for wireless power transmission. In another example, the wireless power transmitter 10 and the wireless power receiver 20 can perform out-of-band communication, in which information is exchanged using a frequency band that is different from the operating frequency used for wireless power transmission.

[0102] For example, the information exchanged between the wireless power transmitter 10 and the wireless power receiver 20 may include each other's status information and control information. Here, the status information and control information exchanged between the transmitter and receiver will become more apparent from the following description of the implementation.

[0103] In-band and out-of-band communication can provide bidirectional communication, but the implementation is not limited to this. In another implementation, in-band and out-of-band communication can provide unidirectional or half-duplex communication.

[0104] For example, one-way communication may, but is not limited to, represent the transmission of information from the wireless power receiver 20 to the wireless power transmitter 10 or from the wireless power transmitter 10 to the wireless power receiver 20.

[0105] The half-duplex communication method is characterized by the activation of bidirectional communication between the wireless power receiver 20 and the wireless power transmitter 10, but only one device can send information at a specific point in time.

[0106] The wireless power receiver 20 according to the embodiment can acquire various status information of the electronic device 30. For example, the status information of the electronic device 30 may include, but is not limited to, current power usage information, information for identifying the executed application, CPU usage information, battery charging status information, battery output voltage / current information, etc., and may include information that can be acquired from the electronic device 30 and used for wireless power control.

[0107] Specifically, according to the embodiment, the wireless power transmitter 10 can send a predetermined packet indicating whether fast charging is supported to the wireless power receiver 20. When it is determined that the wireless power transmitter 10 supports fast charging mode, the wireless power receiver 20 can notify the electronic device 30 that the wireless power transmitter 10 supports fast charging mode. The electronic device 30 can display information indicating that fast charging is possible via a predetermined display device, such as a liquid crystal display.

[0108] Additionally, the user of the electronic device 30 can select a predetermined fast charging request button displayed on the liquid crystal display device and control the wireless power transmission terminal 10 to operate in fast charging mode. In this case, when the user selects the fast charging request button, the electronic device 30 can send a predetermined fast charging request signal to the wireless power receiver 20. The wireless power receiver 20 can generate a charging mode packet corresponding to the received fast charging request signal and send the charging mode packet corresponding to the received fast charging request signal to the wireless power transmission terminal 10, thereby switching the normal low-power charging mode (or baseline charging mode) to fast charging mode.

[0109] Figure 2 This is a block diagram illustrating a wireless charging system according to another embodiment.

[0110] For example, as indicated by reference numeral 200a, the wireless power receiver 20 may include multiple wireless power receiving devices connected to a wireless power transmitter 10 to perform wireless charging. In this case, the wireless power transmitter 10 may divide the power in a time-division manner—but is not limited to this—and transmit the power to the multiple wireless power receiving devices. In another example, the wireless power transmitter 10 may divide the power and transmit the power to the multiple wireless power receiving devices using different frequency bands respectively allocated to the wireless power receiving devices.

[0111] At this point, the number of wireless power receiving devices that can be connected to a wireless power transmission terminal 10 can be adaptively determined based on at least one of the power requirements of each wireless power receiving device, the battery charging status, the power consumption of the electronic device, and the available power of the wireless power transmitting device.

[0112] In another example, as indicated by reference numeral 200b, the wireless power transmitter 10 may include multiple wireless power transmission devices. In this case, the wireless power receiver 20 may be connected to multiple wireless power transmission devices simultaneously and may simultaneously receive power from the connected wireless power transmission devices to perform charging. In this case, the number of wireless power transmission devices connected to the wireless power receiver 20 can be adaptively determined based on the power requirements of the wireless power receiver 20, the battery charging status, the power consumption of the electronic devices, and the available power of the wireless power transmission devices.

[0113] Figure 3 This is a diagram illustrating a procedure for sensing a wireless power receiver in a wireless charging system according to an embodiment.

[0114] For example, a wireless power transmitter may include three transmission coils 111, 112, and 113. Each transmission coil may partially overlap with another transmission coil, and the wireless power transmitter sequentially transmits predetermined sensing signals 117 and 127, such as digital detection signals, through each transmission coil in a predefined order for sensing the presence of a wireless power receiver.

[0115] like Figure 3 As shown, the wireless power transmitter can sequentially transmit sensing signals 117 through a primary sensing signal transmission procedure indicated by reference numeral 110, and identify transmission coils 111 and 112 for receiving signal strength signals 116 from the wireless power receiver 115. Here, the signal strength signal may include information about the signal strength corresponding to the sensing signal measured in the wireless power receiver 115 (hereinafter referred to as a signal strength indicator for ease of description).

[0116] Subsequently, the wireless power transmitter can: sequentially transmit sensing signals 127 via a secondary sensing signal transmission procedure indicated by reference numeral 120; identify a transmission coil with good power transmission efficiency (or charging efficiency) – i.e., good alignment between the transmission coil and the receiving coil – between the transmission coils 111 and 112 for receiving signal strength indicator 126; and perform control to transmit power through the identified transmission coil, i.e., perform wireless charging.

[0117] like Figure 3As shown, the wireless power transmitter uses two sensing signal transmission procedures to more accurately determine which transmission coil is well aligned with the receiving coil of the wireless power receiver.

[0118] like Figure 3 As indicated by reference numerals 110 and 120, if signal strength indicators 116 and 126 are received in the first transmission coil 111 and the second transmission coil 112, the wireless power transmitter selects the best-aligned transmission coil based on the signal strength indicator 126 received in the first transmission coil 111 and the second transmission coil 112, and uses the selected transmission coil to perform wireless charging.

[0119] Figure 4 This is a state transition diagram illustrating the wireless power transmission procedure according to the implementation method;

[0120] Reference Figure 4 The states of a wireless power transmitter used for wireless power transmission can be roughly divided into: selection phase 410, detection phase 420, identification and configuration phase 430, and power transmission phase 440.

[0121] Selection phase 410 can be switched when power transmission begins or when a specific error or event is sensed while power transmission is being maintained. As described below, the specific error or event will become apparent. Additionally, in selection phase 410, the transmitter can monitor the presence of an object on the interface surface. When an object is sensed on the interface surface, the transmitter can switch to detection phase 420 (S401). In selection phase 410, the transmitter sends an analog detection signal with a very short pulse and senses the presence of an object in the effective area of ​​the interface surface based on changes in the current of the transmission coil.

[0122] In the detection phase 420, when an object is detected, the transmitter activates the receiver and sends a digital probe to identify whether the receiver is compatible with the wireless charging standard. In the detection phase 420, if no response signal to the digital probe, such as a signal strength signal, is received from the receiver, the transmitter can switch back to the selection phase 410 (S402). Additionally, in the detection phase 420, if a signal indicating that power transmission has terminated, i.e., a charging termination signal, is received from the receiver, the transmitter can switch back to the selection phase 410 (S403).

[0123] If the probe phase 420 ends, the transmitter can switch to the identification and configuration phase 430 (S404) for identifying the receiver and collecting reception configuration and status information.

[0124] In the identification and configuration phase 430, when an unexpected packet is received, when the expected packet is not received within the predetermined time period (timeout), when a packet transmission error occurs, or when no power transmission contract is established (no power transmission contract), the transmitter may switch to the selection phase 410 (S405).

[0125] Once the receiver identification and configuration are complete, the transmitter can switch to the power transmission phase 240 (S406) for transmitting wireless power.

[0126] In power transmission phase 440, when an unexpected packet is received, when an expected packet is not received within a predetermined time period (timeout), when a predetermined power transmission contract is breached, or when charging is terminated, the transmitter may switch to selection phase 410 (S407).

[0127] Additionally, during the power transmission phase 440, when it is necessary to reconfigure the power transmission contract based on a change in the transmitter state, the transmitter can transition to the identification and configuration phase 430 (S408).

[0128] Power transmission contracts can be configured based on transmitter status and characteristics, as well as receiver status and characteristics. For example, transmitter status information may include information about the maximum amount of power that can be transmitted, information about the maximum number of receivers that can receive power, and receiver status information may include information about the required power.

[0129] Figure 5 It is a state transition diagram illustrating the wireless power transmission procedure.

[0130] Reference Figure 5 The power transmission from transmitter to receiver according to the implementation can be broadly divided into: selection phase 510, detection phase 520, identification and configuration phase 530, negotiation phase 540, calibration phase 550, power transmission phase 560 and renegotiation phase 570.

[0131] When a specific error or event is sensed during the initiation or maintenance of power transmission, selection phase 510 can transition, i.e., it may include, for example, reference numerals S502, S504, S508, S510, and S512. As described below, the specific error or event will become apparent. Additionally, in selection phase 510, the transmitter can monitor the presence of an object on the interface surface. When an object is sensed on the interface surface, the transmitter can transition to detection phase 520. In selection phase 510, the transmitter sends an analog detection signal with a very short pulse and senses the presence of an object in the effective area of ​​the interface surface based on current changes in the transmission coil or primary coil.

[0132] If an object is detected in selection phase 510, the wireless power transmitter can measure the quality factor of the wireless power resonant circuit—for example, the transmission coil and / or resonant capacitor used for wireless power transmission.

[0133] A wireless power transmitter can measure the inductance of a wireless power resonant circuit (e.g., a power transmission coil and / or a resonant capacitor).

[0134] Other accompanying figures will be used to describe the detailed measurement methods.

[0135] In the future, quality factor and / or inductance can be used to determine whether foreign objects are present in negotiation phase 540.

[0136] When an object is detected in the detection phase 520, the transmitter wakes up the receiver and sends a digital probe to identify whether the detected object is a wireless power receiver (S501). In the detection phase 520, if no response signal to the digital probe, such as a signal strength packet, is received from the receiver, the transmitter can switch back to the selection phase 510. Additionally, in the detection phase 520, if a signal indicating that power transmission has been terminated, i.e., a charging termination packet, is received from the receiver, the transmitter can switch back to the selection phase 510 (S502).

[0137] If the probe phase 520 ends, the transmitter can switch to the identification and configuration phase 530 (S503) for identifying the receiver and collecting the receiver's configuration and status information.

[0138] In the identification and configuration phase 530, when an unexpected packet is received, when the expected packet is not received within a predetermined time period (timeout), when a packet transmission error occurs, or when a power transmission protocol is not established (no power transmission protocol), the transmitter may switch to the selection phase 510 (S504).

[0139] The transmitter can determine whether it needs to enter the negotiation phase 540 based on the negotiation field value of the configuration packet received in the identification and configuration phase 530.

[0140] When it is determined that negotiation is required, the transmitter may enter the negotiation phase (S505). In the negotiation phase 540, the transmitter may execute a pre-defined FOD procedure.

[0141] Conversely, when it is determined that no negotiation is required, the transmitter can immediately switch to the power transmission phase 560 (S506).

[0142] During negotiation phase 540, the transmitter may receive a Foreign Object Detection (FOD) status packet that includes a reference quality factor value. Alternatively, it may receive a FOD status packet that includes a reference inductance value. Alternatively, it may receive a status packet that includes both a reference quality factor value and a reference inductance value. In this case, the transmitter may determine a quality factor threshold for FO detection based on the reference quality factor value.

[0143] The transmitter can use a determined quality factor threshold for FO detection and a currently measured quality factor value, such as a quality factor value measured before the detection phase, to detect the presence of FO in the charging area, and control power transmission based on the result of FO detection. For example, power transmission can be stopped when FO is detected, but it is not limited to this.

[0144] The transmitter can use a determined inductance threshold for FO detection and a currently measured quality factor, such as the inductance value measured before the detection phase, to detect the presence of FO in the charging area and control power transmission based on the FO detection result. For example, power transmission can be stopped when FO is detected, but it is not limited to this.

[0145] When an FO is detected, the transmitter can return to the selection phase 510 (S508). Conversely, when an FO is not detected, the transmitter can transition to the power transmission phase 560 (S507 and S509) via the calibration phase 550. Specifically, when an FO is not detected, the transmitter can measure the power loss at the receiving and transmitting ends to determine the strength of the power received at the receiving end and the strength of the power transmitted at the transmitting end in the calibration phase 550. That is, in the calibration phase 550, the transmitter can predict the power loss based on the difference between the transmitted power at the transmitting end and the received power at the receiving end. According to one embodiment, the transmitter can use the predicted power loss to calibrate a threshold for FOD.

[0146] In the power transmission phase 560, when an unexpected packet is received, when an expected packet is not received within a predetermined time period (timeout), when a power transmission contract breach occurs, or when charging ends, the transmitter may switch to the selection phase 510 (S510).

[0147] Additionally, during the power transmission phase 560, if it is necessary to reconfigure the power transmission contract based on changes in the transmitter's state, the transmitter can transition to the renegotiation phase 570 (S511). At this point, when the renegotiation concludes normally, the transmitter can return to the power transmission phase 560 (S513).

[0148] Power transmission contracts can be configured based on transmitter status and characteristics, as well as receiver status and characteristics. For example, transmitter status information may include information about the maximum amount of power that can be transmitted, information about the maximum number of receivers that can receive power, and receiver status information may include information about the required power.

[0149] If renegotiation fails to complete properly, the transmitter may stop power transmission to the receiver and transition to selection phase 510 (S512).

[0150] Figure 6 This is a block diagram illustrating the structure of a wireless power transmitter according to an embodiment.

[0151] Reference Figure 6 The wireless power transmitter 600 may generally include: a power converter 610, a power transmission unit 620, a communication unit 630, a controller 640, and a sensing unit 650. The configuration of the wireless power transmitter 600 is not necessarily required, and therefore may include more or fewer components.

[0152] like Figure 6 As shown, the power converter 610 can receive DC power from the power supply 660 and convert the DC power into AC power with a predetermined intensity.

[0153] For this purpose, the power converter 610 may include: a DC-DC converter 611, an inverter 612, and a frequency generator 613. Here, the inverter 612 may be a half-bridge inverter or a full-bridge inverter, and is not limited thereto. Any circuit configuration capable of converting DC power into AC power with a specific operating frequency can be used.

[0154] The DC-DC converter 611 can perform the function of converting DC power received from the power supply 650 into DC power of a specific intensity according to the control signal of the controller 640.

[0155] At this time, the sensing unit 650 can measure the voltage / current of the converted DC power and provide the voltage / current of the converted DC power to the controller 640.

[0156] Additionally, the sensing unit 650 can measure the internal temperature of the wireless power transmitter 600 and provide the measurement results to the controller 640 to determine whether overheating has occurred.

[0157] For example, controller 640 can adaptively cut off power supplied from power source 650 or prevent power from being supplied to inverter 612 based on voltage / current values ​​measured by sensing unit 650. A predetermined power cutting-off circuit for cutting off power supplied from power source 650 or power supplied to inverter 612 may also be provided on one side of power converter 610.

[0158] Inverter 612 can convert DC-DC converted power into AC power based on a reference AC signal generated by frequency generator 613. At this time, the frequency of the reference AC signal, i.e., the operating frequency, can be dynamically changed according to the control signal of controller 640. The wireless power transmitter 600 according to the embodiment can adjust the operating frequency to adjust the intensity of the transmitted power. For example, controller 640 can: receive power reception status information and / or power control signals from the wireless power receiver via communication unit 630, determine the operating frequency based on the received power reception status information and / or power control signals, and dynamically control frequency generator 613 to generate the determined operating frequency. For example, power reception status information may include, but is not limited to, information on the intensity of the rectifier output voltage, information on the intensity of the current applied to the receiving coil, etc. Power control signals may include signals for requesting an increase in power, signals for requesting a decrease in power, etc.

[0159] The power transmission unit 620 may include a multiplexer 621 and a transmission coil unit 622. Here, the transmission coil unit 622 may include a first transmission coil to an nth transmission coil. Additionally, the power transmission unit 620 may also include a carrier generator (not shown) for generating a specific carrier frequency for power transmission. In this case, the carrier generator can generate an AC signal with a specific carrier frequency for mixing with the output AC power received by the inverter 612 through the multiplexer 621. In one embodiment, it should be noted that the frequencies of the AC power sent to the transmission coils may be different from each other. In another embodiment, a predetermined frequency controller with the function of differently adjusting the LC resonant characteristics of the transmission coils can be used to set the resonant frequencies of the transmission coils differently.

[0160] Multiplexer 621 can perform a switching function for sending AC power to a transmission coil selected by controller 640. Controller 640 can select the transmission coil for sending power to the wireless power receiver based on the signal strength indicator of each transmission coil.

[0161] If multiple wireless power receivers are connected, the controller 640, according to one embodiment, can transmit power via time-division multiplexing of the transmission coils. For example, if the wireless power transmitter 600 identifies three wireless power receivers (i.e., first receiver to third receiver) via three different transmission coils—i.e., first transmission coil to third transmission coil—the controller 640 can control the multiplexer 621 to transmit AC power only through a specific transmission coil in a specific time slot. While the amount of power sent to the wireless power receivers can be controlled based on the length of the time slot allocated to each transmission coil, this is merely one embodiment. In another example, the intensity of the output DC power of the DC-DC converter 611 can be controlled during the time slot allocated to each transmission coil to control the power transmitted to each wireless power receiver.

[0162] The controller 640 can control the multiplexer 621 to sequentially transmit sensing signals through the first transmission coil to the nth transmission coil 622 during the initial sensing signal transmission procedure. At this time, the controller 640 can use the timer 655 to identify the time when the sensing signal will be transmitted, and when the sensing signal transmission time arrives, control the multiplexer 621 to transmit the sensing signal through the corresponding transmission coil. For example, during the detection transmission phase, the timer 650 can send a specific event signal to the controller 640 at a predetermined time period, and whenever the corresponding event signal is sensed, the controller 640 can control the multiplexer 621 to transmit the digital detection through the corresponding transmission coil.

[0163] Additionally, the controller 640 can receive a predetermined transmission coil identifier from the demodulator 632. This predetermined transmission coil identifier is used to identify which transmission coil receives the response signal, such as a signal strength signal, during the primary sensing signal transmission procedure. At this time, the controller 640 can receive a signal strength indicator corresponding to the transmission coil identifier from the demodulator 632. Subsequently, in the secondary sensing signal transmission procedure, the controller 640 can control the multiplexer 621 to transmit the sensing signal only through one or more transmission coils that received the signal strength indicator during the primary sensing signal transmission procedure. In another example, if the signal strength indicator is received through multiple transmission coils during the primary sensing signal transmission procedure, the controller 640 can determine the transmission coil through which it receives the signal strength indicator with the maximum value as the transmission coil through which it will first transmit the sensing signal in the secondary sensing signal transmission procedure, and control the multiplexer 621 based on the determination result.

[0164] The communication unit 630 may include at least one of a modulator 631 or a demodulator 632.

[0165] Modulator 631 can modulate the control signal generated by controller 640 and send the modulated signal to multiplexer 621. The modulation method for modulating the control signal may include, but is not limited to: frequency shift keying (FSK) modulation, Manchester coded modulation, phase shift keying (PSK) modulation, pulse width modulation, differential biphase modulation, etc.

[0166] When a signal received through the transmission coil is sensed, the demodulator 632 can demodulate the sensed signal and send it to the controller 640. Here, the demodulated signal may include, but is not limited to: a signal strength indicator, an error correction (EC) indicator for power control during wireless power transmission, an end-of-charge (EOC) indicator, an overvoltage / overcurrent indicator, etc., and may also include various status information for identifying the status of the wireless power receiver.

[0167] Additionally, the demodulator 632 can identify which transmission coil receives the demodulated signal and provide the controller 640 with a predetermined transmission coil identifier corresponding to the identified transmission coil.

[0168] Additionally, demodulator 632 can demodulate the signal received via transmission coil 623 and transmit the demodulated signal to controller 640. For example, the demodulated signal may include, but is not limited to, a signal strength indicator, and may include various status information of the wireless power receiver.

[0169] For example, the wireless power transmitter 600 can acquire a signal strength indicator via in-band communication, which is used to perform communication with the wireless power receiver using the same frequency used for wireless power transmission.

[0170] Furthermore, the wireless power transmitter 600 can not only transmit wireless power through the transmission coil unit 622, but also exchange various control signals and status information with the wireless power receiver through the transmission coil unit 622. In another example, individual coils corresponding to the first to nth transmission coils of the transmission coil unit 622 can also be included in the wireless power transmitter 600, and in-band communication with the wireless power receiver can be performed using these individual coils.

[0171] Despite Figure 6 The description states that the wireless power transmitter 600 and wireless power receiver perform in-band communication, but this is merely exemplary and short-range bidirectional communication can be performed via a frequency band different from the frequency band used to transmit the wireless power signal. For example, short-range bidirectional low-power communication can be any of Bluetooth communication, RFID communication, UWB communication, and ZigBee communication.

[0172] In addition, although in Figure 6 The description of the wireless power transmitter 600 includes a power transmission unit 620 comprising a multiplexer 621 and multiple transmission coils 622, but this is merely one embodiment. In another embodiment, the power transmission unit 620 may include a single transmission coil.

[0173] Figure 7 It is shown that... Figure 6 The diagram shows a block diagram of the structure of a wireless power transmitter and a wireless power receiver that work together.

[0174] Reference Figure 7 The wireless power receiver 700 may include a receiving coil 710, a rectifier 720, a DC-DC converter 730, a load 740, a sensing unit 750, a communication unit 760, and a main controller 770. The communication unit 760 may include a demodulator 761 and a modulator 762.

[0175] Despite Figure 7 The wireless power receiver 700 shown in the example is illustrated as exchanging information with the wireless power transmitter 600 via in-band communication, but this is merely exemplary, and the communication unit 760 according to another embodiment can provide short-range two-way communication via a frequency band different from the frequency band used to transmit wireless power signals.

[0176] The AC power received by the receiving coil 710 can be sent to the rectifier 720. The rectifier 720 can convert the AC power into DC power and send the DC power to the DC-DC converter 730. The DC-DC converter 730 can convert the intensity of the DC power output from the rectifier into the specific intensity required by the load 740 and send the converted power to the load 740.

[0177] The sensing unit 750 can measure the intensity of the DC power output from the rectifier 720 and provide this intensity to the main controller 770. Additionally, the sensing unit 750 can measure the intensity of the current applied to the receiving coil 710 based on wireless power reception and send the measurement result to the main controller 770. Furthermore, the sensing unit 750 can measure the internal temperature of the wireless power receiver 700 and provide the measured temperature value to the main controller 770.

[0178] For example, the main controller 770 can compare the intensity of the DC power output from the rectifier with a predetermined reference value and determine whether an overvoltage has occurred. Upon determining that an overvoltage has occurred, a predetermined packet indicating that an overvoltage has occurred can be generated and sent to the modulator 762. The signal modulated by the modulator 762 can be sent to the wireless power transmitter 600 via the receiving coil 710 or a separate coil (not shown). If the intensity of the DC power output from the rectifier is equal to or greater than the predetermined reference value, the main controller 770 can determine that a sensed signal has been received and, upon receiving the sensed signal, execute control to send a signal strength indicator corresponding to the sensed signal to the wireless power transmitter 600 via the modulator 762. In another example, the demodulator 761 can demodulate the AC power signal between the receiving coil 710 and the rectifier 720 or the DC power signal output from the rectifier 720, identify whether a sensed signal has been received, and provide the identification result to the main controller 770. At this time, the main controller 770 can perform control to send a signal strength indicator corresponding to the sensed signal through the modulator 761.

[0179] Specifically, according to the implementation, the main controller 770 can determine whether the connected wireless power transmitter is performing fast charging based on the information demodulated by the demodulator 760.

[0180] Additionally, when from Figure 1 When the electronic device 30 receives a predetermined fast charging request signal for requesting fast charging, the main controller 770 can generate a charging mode group corresponding to the received fast charging request signal and send the charging mode group to the modulator 761. The fast charging request signal from the electronic device can be received according to a user menu selection on a predetermined user interface.

[0181] When it is determined that the connected wireless power transmitter supports fast charging mode, according to another embodiment, the main controller 770 may perform control based on the remaining battery level to automatically request fast charging from the wireless power transmitter or enable the wireless power transmitter to stop fast charging and switch to normal low-power charging mode.

[0182] According to another embodiment, the main controller 770 can monitor the power consumption of the electronic device in real time while performing charging in a normal low-power charging mode. If the power consumption of the electronic device is equal to or greater than a predetermined reference value, the main controller 770 can generate a predetermined charging mode packet for requesting a switch to a fast charging mode and send the predetermined charging mode packet to the modulator 761.

[0183] According to another embodiment, the main controller 770 can compare the internal temperature value measured by the sensing unit 750 with a predetermined reference value and determine whether overheating has occurred. If overheating occurs during fast charging, the main controller 770 can generate and send a charging mode group, causing the wireless power transmitter to switch to a normal low-power charging mode.

[0184] According to another embodiment, the main controller 770 can determine whether a change in charging mode is needed based on at least one of the following: battery charging rate, voltage strength from rectifier output, CPU usage in electronic device, and user menu selection. If a change in charging mode is needed, the main controller 770 can generate a charging mode group including the value of the charging mode to be changed and send the charging mode group to the wireless power transmitter.

[0185] Figure 8 This is a view illustrating a method for modulating and demodulating wireless power signals according to an embodiment.

[0186] like Figure 8 As indicated by reference numeral 810 in the accompanying drawings, the wireless power transmitter 10 and the wireless power receiver 20 can encode or decode packets to be transmitted based on internal clock signals with the same period.

[0187] In the following text, reference will be made to Figures 1 to 8 This section describes in detail the method for encoding the packets to be sent.

[0188] Reference Figure 1 If the wireless power transmitter 10 or the wireless power receiver 20 does not send a special packet, the wireless power signal can be as follows: Figure 1 The attached reference numeral 41 indicates an unmodulated AC signal with a specific frequency. In contrast, if the wireless power transmitter 10 or the wireless power receiver 20 transmits a special packet, the wireless power signal can be as follows: Figure 1 The reference numeral 42 indicates an AC signal modulated using a specific modulation method. For example, the modulation method may include, but is not limited to: amplitude modulation method, frequency modulation method, frequency and amplitude modulation method, phase modulation method, etc.

[0189] Differential biphase coding is applicable to binary data packets generated by wireless power transmitter 10 or wireless power receiver 20, as indicated by reference numeral 820 in the attached figure. Specifically, differential biphase coding has two state transitions for encoding data bit 1 and one state transition for encoding data bit 0. That is, data bit 1 is encoded such that the transition between the HI state and the LO state occurs at the rising and falling edges of the clock signal, and data bit 0 is encoded such that the transition between the HI state and the LO state occurs at the rising edge of the clock signal.

[0190] The byte encoding method indicated by reference numeral 830 is applicable to encoded binary data. Referring to reference numeral 830, the byte encoding method according to the embodiment may be as follows: inserting start bits and stop bits for identifying the start and stop of the bit stream associated with the 8-bit encoded binary bit stream, and check bits for sensing whether an error has occurred in the bit stream (byte).

[0191] Figure 9 This is a view showing the format of the grouping according to the implementation method.

[0192] Reference Figure 9 The packet format 900 for information exchange between the wireless power transmitter 10 and the wireless power receiver 20 may include: a preamble 910 field for obtaining synchronization for demodulation of the corresponding packet and identifying the accurate start bit of the corresponding packet; a header 920 field for identifying the type of message included in the corresponding packet; a message 930 field for transmitting the content (or payload) of the corresponding packet; and a checksum 940 field for identifying whether an error has occurred in the corresponding packet.

[0193] like Figure 9 As shown, the packet receiver can identify the size of the message 930 included in the corresponding packet based on the value of the header 920.

[0194] Additionally, header 920 can be defined for each step of the wireless power transmission procedure, and the value of header 920 can be defined as the same in different stages. For example, refer to... Figure 9 It should be noted that the header value corresponding to the end of the power transmission during the detection phase and the end of the power transmission during the power transmission phase is 0x02.

[0195] Message 930 includes data to be sent by the transmitting end of the corresponding packet. For example, the data included in the fields of Message 930 can be a report, request, or response, but is not limited to these.

[0196] According to another embodiment, the packet 900 may further include at least one of transmitter identification information for identifying the transmitter for transmitting the corresponding packet and receiver identification information for identifying the receiver for receiving the corresponding packet. The transmitter identification information and receiver identification may include IP address information, MAC address information, product identification information, etc. However, this disclosure is not limited to this and may include information for distinguishing between the receiver and transmitter in a wireless charging system.

[0197] If the corresponding packet is received by multiple devices, the packet 900 according to another embodiment may also include predetermined group identification information for identifying the receiving group.

[0198] Figure 10 This is a view showing the type of packets transmitted from a wireless power receiver to a wireless power transmitter according to an embodiment.

[0199] Reference Figure 10 Packets transmitted from a wireless power receiver to a wireless power transmitter may include: a signal strength packet for transmitting information about the strength of the sensed detection signal; a power transmission termination (end of power transmission) request for the transmitter to stop power transmission from the transmitter; a power control delay packet for transmitting information about the time wait before actual power is controlled after receiving a control error packet for control; a configuration packet for transmitting receiver configuration information; an identification packet and an extended identification packet for transmitting receiver identification information; a general request packet for transmitting a general request message; a special request packet for transmitting a special request message; a FOD status packet for transmitting a reference quality factor value for FOD detection; a control error packet for controlling the power transmitted by the transmitter; a renegotiation packet for initiating renegotiation; a 24-bit received power packet for transmitting information about the strength of the received power; and a charging status packet for transmitting information about the current charging status of the load.

[0200] In-band communication can be used to transmit packets from a wireless power receiver to a wireless power transmitter. In-band communication uses the same frequency band as that used for transmitting wireless power.

[0201] Figure 11 This is a view showing the structure of a foreign object detection device according to an embodiment.

[0202] The foreign object detection device 1100 according to this embodiment can be implemented in a wireless power transmission device, but this is only one embodiment. The foreign object detection device can also be implemented in a measuring device used for certifying wireless power receiving devices.

[0203] Reference Figure 11The foreign object detection device 1100 may include a power supply 1101, a DC-DC converter 1110, an inverter 1120, a resonant capacitor 1130, a measurement unit 1140, a communication unit 1160, a sensing unit 1170, and a controller 1180. The foreign object detection device 1100 according to this embodiment may be included in a wireless power transmission device.

[0204] The resonant circuit 1130 includes a resonant capacitor 1131 and a transmission coil (or inductor) 1132, and the communication unit 1160 may include at least one of a demodulator 1161 and a modulator 1162.

[0205] The power supply 1101 can receive DC power through an external power terminal and transmit the DC power to the DC-DC converter 1110.

[0206] DC-DC converter 1110 can convert the intensity of DC power input from power supply 1101 into a specific intensity of DC power under the control of controller 1180. For example, DC-DC converter 1110 may include, but is not limited to, a variable voltage generator capable of adjusting the intensity of the voltage.

[0207] Inverter 1120 can convert DC power into AC power. Inverter 1120 can convert DC power input controlled by multiple switches into AC power signals and output AC power signals.

[0208] For example, inverter 1120 can be at least one of a half-bridge inverter or a full-bridge inverter.

[0209] If inverter 1120 includes both a half-bridge circuit and a full-bridge circuit, controller 1180 can dynamically determine whether inverter 1120 operates as a half-bridge circuit or a full-bridge circuit. According to one embodiment, the wireless power transmission device can adaptively control the bridge mode of inverter 1120 based on the power intensity required by the wireless power receiving device or the power level of the wireless power receiving device. Here, the bridge mode includes a half-bridge mode for generating AC power signals using a half-bridge circuit and a full-bridge mode for generating AC signals using a full-bridge circuit.

[0210] For example, if the wireless power receiving device requests 5W or less of low power, or if the power level of the wireless power receiving device corresponds to a predetermined low power (LP) level, the controller 1180 can control the inverter 1120 to operate in half-bridge mode. Conversely, if the wireless power receiving device requests 15W of high power, or if the power level corresponds to an intermediate power (MP) level, the controller 1180 can control the inverter 1120 to operate in full-bridge mode.

[0211] In another example, the wireless power transmission device can adaptively determine the bridge mode based on the charging mode. Here, the charging mode can include a baseline charging mode and a fast charging mode. In the baseline charging mode, the inverter 1120 can operate in half-bridge mode. In the fast charging mode, the inverter 1120 can operate in full-bridge mode. The output power of the transmitter in the fast charging mode is set to be higher than the output power of the transmitter in the baseline charging mode.

[0212] In another example, the wireless power transmission device can adaptively determine the bridge mode based on the temperature sensed by the sensing unit 1170, and control the inverter 1120 according to the determined bridge mode. For example, if the temperature of the wireless power transmission device exceeds a predetermined reference value when transmitting wireless power in half-bridge mode, the controller 1180 can perform control to deactivate the half-bridge mode and activate the full-bridge mode. That is, the wireless power transmission device can increase the voltage through the full-bridge circuit used for transmitting power of the same intensity and decrease the intensity of the current flowing in the resonant circuit 1130, thereby maintaining the internal temperature of the wireless power transmission device at or below the predetermined reference value. Typically, the heat generated in electronic components installed in electronic devices may be more sensitive to the intensity of the current than to the intensity of the voltage applied to the electronic components.

[0213] In addition, the inverter 1120 can not only convert DC power to AC power, but also dynamically change the intensity of the AC power transmitted to the resonant circuit 1130.

[0214] For example, inverter 1120 can adjust the strength of the output AC power by adjusting the frequency of the reference AC signal used to generate AC power under the control of controller 1180. To this end, inverter 1120 may include a frequency oscillator for generating the reference AC signal with a specific frequency. However, this is merely exemplary, and the frequency oscillator may be mounted independently of inverter 1120 on one side of foreign object detection device 1100.

[0215] In another example, a fixed frequency is suitable for wireless power transmission devices. In this case, the foreign object detection device 1100 may also include a gate driver (not shown) for controlling a switch disposed in the inverter 1120. In this case, the gate driver may receive at least one pulse width modulation signal from the controller 1180 and control the switch of the inverter 1120 according to the received pulse width modulation signal, for example, configuring the MOFET switch of a selected bridge circuit, but not limited thereto. The controller 1180 may control the duty cycle, i.e., the duty rate, and the phase of the pulse width modulation signal to control the strength of the output power of the inverter 1120. The controller 1180 may adaptively control the duty cycle and phase of the pulse width modulation signal based on feedback signals received from the wireless power receiving device, thereby controlling the strength of the power transmitted through the resonant circuit 1130.

[0216] The measuring unit 1140 can measure at least one of the voltage level across the resonant capacitor 1131 or the current level flowing in the transmission coil 1132, based on control signals from the controller 1180. For this purpose, the measuring unit 1140 may include a voltage sensor and a current sensor. The controller 1180 can calculate the intensity of the power transmitted through the resonant circuit 1130 based on the sensing information received from the measuring unit 1140. Additionally, the measuring unit 1140 may include a temperature sensor for measuring the temperature corresponding to a specific location and / or the interior of the device and transmitting that temperature to the controller 1180.

[0217] Before entering the detection phase 420 or 520, when an object placed in the charging area is detected in the selection phase 410 or 510, the measurement unit 1140 can measure the voltage across the resonant capacitor 1131 and calculate the quality factor value corresponding to the resonant circuit 1130 in a state where power transmission is stopped.

[0218] In addition, the measurement unit 1140 can also calculate the inductance value corresponding to the resonant circuit 1130.

[0219] At least one of the calculated quality factor or inductance value can be sent to the controller 1180, which can store the value received from the measurement unit 1140 in a predetermined recording area of ​​a predetermined memory (not shown).

[0220] When a FOD status packet is received from modulator 1162 during the negotiation phase, controller 1180 can determine a threshold (or threshold range) for determining the presence of a foreign object based on the information included in the FOD status packet. Here, the determined threshold may include, but is not limited to, a quality factor threshold, and any threshold predefined for foreign object detection can be used.

[0221] If the value set to determine the presence of foreign objects is a threshold range, then that threshold range can be a quality factor threshold range.

[0222] Additionally, controller 1180 can determine the presence of foreign objects based on the path loss of transmitted power. Here, the path loss can be obtained by subtracting the actual power received by the wireless power receiving device from the power intensity transmitted through resonant circuit 1130. Controller 1180 can confirm the power intensity currently received by the wireless power receiving device based on information fed back from the wireless power receiving device. Controller 1180 can compare the calculated path loss with a predetermined path loss threshold (or threshold range) to determine the presence of foreign objects.

[0223] Specifically, the path loss threshold (or threshold range) can be set according to different charging modes. For example, the path loss threshold (or threshold range) corresponding to the fast charging mode can be greater than the path loss threshold (or threshold range) corresponding to the baseline charging mode.

[0224] The controller 1180 can receive signal strength packets that include information about the strength of the received power during the power transmission phase 440 or 510.

[0225] The controller 1180 can compare a predefined or determined received power strength threshold (or threshold range) corresponding to the current transmitted power strength with the received power strength obtained (or calculated) based on feedback information received from the wireless power receiving device to determine whether the information received from the wireless power receiver regarding the received power strength has a normal value. Here, the received power strength threshold (or threshold range) can be determined based on the charging mode. For example, the range of power that can be transmitted in fast charging mode may be between 10 watts and 20 watts. In this case, it is assumed that the received power strength threshold corresponding to the fast charging mode is 6W.

[0226] When the received power strength confirmed based on the signal strength packet is 6W or greater, the controller 1180 can determine that the information about the received power strength included in the signal strength packet is normal.

[0227] However, when the received power strength confirmed based on the signal strength group is less than 6W, the controller 1180 determines that the information about the received power strength included in the signal strength group is abnormal.

[0228] In another example, controller 1180 can compare the ratio of the current transmitted power strength to the received power strength with a predetermined threshold ratio to determine whether the information regarding the received power strength is normal. Here, the threshold ratio can be determined based on the maximum path loss ratio pre-measured corresponding to the transmitter.

[0229] When it is determined that the information regarding the received power strength is abnormal, the controller 1180 may apply a predetermined offset to the received power strength to perform correction. For example, when it is determined that the information is abnormal in fast charging mode, the controller 1180 may correct the received power strength by adding a predetermined offset to the received power strength.

[0230] The controller 1180 can calculate path loss based on the current transmitted power intensity and the corrected received power intensity. The controller 1180 can then compare the calculated path loss with a predetermined path loss threshold to determine whether a foreign object has been placed on the wireless power transmission path.

[0231] In another example, the received power strength threshold can be determined based on the transmittable power range in charging mode and a predetermined maximum path loss ratio (or maximum path loss value). If the transmittable power range in the current charging mode is 10 watts to 18 watts and the predetermined maximum path loss ratio is 50%, then the receiver's received power strength has a range of 5 watts to 9 watts. However, if the received power strength obtained based on actual signal strength packets is less than 5 watts, the controller 1180 can determine that the information about the received power strength included in the signal strength packets is abnormal. In this case, the controller 1180 can apply a predetermined offset corresponding to the current charging mode to correct the received power strength.

[0232] Of course, if the information about the received power strength is normal, the controller 1180 can calculate the wireless power path loss based on the current transmitted and received power strength, but does not perform a separate correction procedure.

[0233] According to the embodiment, the controller 1180 can selectively execute at least one of a foreign object detection program based on a quality factor or a foreign object detection program based on path loss, according to user settings.

[0234] According to another embodiment, the controller 1180 can compare a quality factor threshold determined based on FOD status packets received during the negotiation phase with a measured quality factor value to determine whether foreign objects are present, and can calculate path loss based on current transmitted power strength and received signal strength packets during the power transmission phase, and determine whether foreign objects are present based on the calculated path loss.

[0235] For example, when the presence of a foreign object is determined in two outcomes, the controller 1180 can ultimately determine that a foreign object is present.

[0236] In another example, controller 1180 may finally determine the presence of a foreign object when either of the two determinations is found to be present.

[0237] According to another embodiment, the controller 1180 can dynamically execute a foreign object detection procedure based on path loss according to the type of wireless power receiver identified in the identification and configuration phases 420 and 520. Here, the type of the identified wireless power receiver can be determined based on software / firmware / protocol version information, manufacturer information, model information, receiver category or type, etc. For example, if it is confirmed that the identified wireless power receiver is from a specific manufacturer and / or a specific model, the controller 1180 can execute a foreign object detection procedure based on path loss and control another wireless power receiver to execute a foreign object detection procedure based on the quality factor.

[0238] Figure 12 This is a view showing the structure of the foreign object detection status group message.

[0239] Reference Figure 12 The foreign object detection status packet message can be 2 bytes long and includes: a reserved 1201 field with a length of 6 bits, a pattern 1202 field with a length of 2 bits, and a reference quality factor 1203 field with a length of 1 byte. Here, all bits of the reserved 1201 field are recorded with 0.

[0240] As indicated by reference numeral 1204 in the attached figure, if the mode 1202 field is set to the binary number "00", this may mean that the reference quality factor value measured and determined while the wireless power receiver is powered off is recorded in the reference quality factor value 1203 field.

[0241] The reference quality factor can be set to the minimum of a first quality factor and a second quality factor. The first quality factor is measured at the center where the transmitting coil (primary coil) and the receiving coil (secondary coil) are well aligned, with no external current (FO) near the wireless power receiver in the charging area. The second quality factor is measured when the wireless power receiver moves away from the center by a predetermined distance (e.g., + / -5 mm on the x-axis and + / -5 mm on the y-axis) without rotation of the wireless power receiver. Here, the second quality factor can include quality factors measured at at least four locations.

[0242] Figure 13 This is a state transition diagram showing the foreign object detection method in a foreign object detection device according to an embodiment.

[0243] Reference Figure 13 When an object is detected in the charging area (S1301), the foreign object detection device can measure and store the quality factor of the resonant circuit in a state where wireless power transmission is temporarily stopped, and then enter the detection phase 1320 (S1302).

[0244] During the detection phase 1320, the foreign object detection device can periodically send predetermined power signals, such as digital detection signals, to identify the wireless power receiver.

[0245] When a response signal, such as a signal strength signal (or signal strength packet), is received during the detection phase 1320, the foreign object detection device can enter the identification and configuration phase 1330 to receive identification packets and configuration packets. The foreign object detection device can authenticate the receiver based on the received identification packets and set predetermined configuration parameters for power transmission to the receiver (S1303).

[0246] When the identification and configuration of the wireless power receiver are completed normally, the foreign object detection device can enter the negotiation phase 1340 to receive a foreign object detection status packet including a reference quality factor value. The foreign object detection device can determine a quality factor threshold for determining the presence of a foreign object based on the information included in the foreign object detection status packet, and compare the determined quality factor threshold with a previously measured and stored quality factor value to determine the presence of a foreign object (S1304).

[0247] If a foreign object is detected, the foreign object detection device can stop power transmission and return to the selection phase 1310. In contrast, if no foreign object is detected, the foreign object detection device can enter the power transmission phase 1350 to begin wireless charging of the identified wireless power receiver.

[0248] During the power transmission phase 1350, the foreign object detection device can execute a foreign object detection procedure based on path loss.

[0249] During the power transmission phase 1350, the foreign object detection device can perform power control based on a predetermined first feedback signal, such as a control error grouping.

[0250] The foreign object detection procedure based on path loss, indicated by reference numeral 1305, will be described in detail below.

[0251] During power control, the foreign object detection device can identify (or calculate) the current received power strength of the wireless power receiver based on a predetermined second feedback signal, such as a signal strength packet, which includes information about the received power strength. At this time, the foreign object detection device can determine whether the information received from the receiver is normal based on the current transmitted and received power strengths.

[0252] For example, a foreign object detection device can compare a received power strength threshold determined corresponding to the current transmitted power strength (or current charging mode) with the current received power strength to determine whether the information received from the wireless power receiver is normal.

[0253] When the received information is determined to be abnormal, the foreign object detection device can correct the received power intensity by applying a predetermined offset. Of course, when the received information is normal, the foreign object detection device does not perform a separate correction procedure.

[0254] Foreign object detection equipment can calculate path loss based on the current transmitted power intensity and the current (or corrected) received power intensity, and compare the calculated path loss with a predetermined path loss threshold (or threshold range) to determine the presence of a foreign object. Here, the path loss threshold can be determined based on different charging modes. In another example, the path loss threshold can be determined proportionally to the current transmitted power intensity.

[0255] When a foreign object is detected in step 1305, the foreign object detection device may return to the selection phase 1310. Additionally, the foreign object detection device may return to the selection phase 1310 when the wireless power receiver is abnormally removed from the charging area or when charging is complete.

[0256] Of course, if no foreign object is detected in step 1305, the foreign object detection device can maintain the power transmission phase 1350.

[0257] Figure 14 This is a state transition diagram illustrating a foreign object detection method in a wireless power transmission device according to another embodiment.

[0258] Reference Figure 14 When an object is detected in the charging area (S1401), the foreign object detection device can measure the quality factor of the resonant circuit while the wireless power transmission is temporarily stopped, and store the quality factor in a predetermined recording area, and then enter the detection stage 1420 (S1402).

[0259] During the detection phase 1420, the foreign object detection device can periodically send predetermined power signals, such as digital detection signals, to identify the wireless power receiver.

[0260] When a response signal, such as a signal strength signal (or signal strength packet), is received in the detection phase 1420, the foreign object detection device can enter the identification and configuration phase 1430 to receive identification packets and configuration packets.

[0261] The foreign object detection device can identify the type of receiver placed in the charging area based on the received identification packet. At this time, the foreign object detection device can determine whether the foreign object detection procedure based on path loss is applicable to the identified receiver type (S1403).

[0262] In this embodiment, it is assumed that the path loss-based foreign object detection procedure is applicable to the identified receiver type. Of course, if the path loss-based foreign object detection procedure is not applicable to the identified receiver type, the foreign object detection device may execute a foreign object detection procedure based on the quality factor value in the negotiation phase (or another foreign object detection procedure).

[0263] When the identification and configuration of the wireless power receiver are completed normally, the foreign object detection device can enter the negotiation phase 1440. At this time, when the foreign object detection procedure based on path loss is applicable to the identified receiver type, the foreign object detection device may not execute the foreign object detection procedure based on the quality factor value, and may enter the power transmission phase 1450 (S1404) when the negotiation procedure is completed normally.

[0264] The following text will describe it in detail. Figure 14 Step 1405 is shown in the figure.

[0265] The foreign object detection device can dynamically control the transmitted power intensity based on the control error packets received in the power transmission phase 1450.

[0266] During power control, the foreign object detection device can periodically receive signal strength packets from the receiver, including information about the received power intensity.

[0267] Foreign object detection equipment can determine whether the information received from the receiver regarding the power intensity is normal.

[0268] For example, foreign object detection equipment can determine whether the information about the received power intensity is normal based on the ratio of the received power intensity to the currently transmitted power intensity.

[0269] In another example, the foreign object detection device can compare the received power intensity threshold determined according to the currently set charging mode with the received power intensity to determine whether the received information is normal.

[0270] In another example, the foreign object detection device can determine whether the received power intensity is included in a predefined range of received power intensity thresholds based on the currently set charging mode, in order to determine whether the received information is normal.

[0271] In another example, the foreign object detection device can determine a received power strength threshold corresponding to the current transmitted power strength. Here, the received power strength threshold can be set as the minimum received power strength that the wireless power receiver can receive corresponding to the current transmitted power strength. In this case, when the received power strength confirmed (or calculated) based on signal strength groups is less than the determined received power strength threshold, the foreign object detection device can determine that the information received from the receiver regarding the received power strength is abnormal.

[0272] When the information received from the receiver regarding the received power strength is abnormal, the foreign object detection device can apply a predetermined offset to the received power strength to perform correction. Here, the offset can be dynamically determined proportionally to the current transmitted power strength or power level (or charging mode) or the type of receiver requested by the receiver. Power levels can be categorized as low power levels, intermediate power levels, etc., but are not limited to these. Power levels can be defined differently depending on the applied standards and the design of those skilled in the art. In another example, the offset can be a fixed value.

[0273] For example, the corrected received power strength ARP can be calculated by adding an offset to the acquired (or calculated) received power strength RP, but is not limited to this.

[0274] Foreign object detection equipment can calculate path loss based on the current transmitted power intensity and the corrected received power intensity, and compare the calculated path loss with a predetermined path loss threshold to determine whether there are foreign objects in the wireless power transmission path.

[0275] For example, the path loss threshold can be a predefined fixed value.

[0276] In another example, the path loss threshold can be dynamically determined based on the type of transmitter and receiver.

[0277] In another example, the path loss threshold can be dynamically determined based on the current power transmission intensity.

[0278] In another example, the path loss threshold can be determined in relation to the currently set charging mode.

[0279] When the calculated path loss exceeds a predetermined path loss threshold, the foreign object detection device can determine that there is a foreign object in the wireless transmission path.

[0280] When a foreign object is detected in step 1405, the foreign object detection device may return to the selection phase 1310. Additionally, the foreign object detection device may return to the selection phase 1410 when the wireless power receiver is abnormally removed from the charging area or when charging is complete.

[0281] Of course, if no foreign object is detected in step 1405, the foreign object detection device can maintain the power transmission phase 1450.

[0282] Figure 15 This is a flowchart illustrating a foreign object detection method according to an embodiment.

[0283] Reference Figure 15When entering the power transmission phase, the wireless power transmitter can control the transmitted power intensity TP based on a first feedback packet (S1501). At this time, the wireless power transmitter can use a measuring unit installed in the wireless power transmitter to measure the intensity of the power transmitted through the resonant circuit. Here, the first feedback packet can be a control error packet as defined in the Qi standard, but this is merely one implementation method. It should be noted that the feedback signal used for power control can vary according to the wireless power transmission standard applied to the wireless power transmitter.

[0284] During the power transmission phase, the wireless power transmitter can receive a second feedback packet (S1502) including information about the received power strength from the wireless power receiver. At this time, the wireless power transmitter can calculate the received power strength RP based on the received power strength information. Here, the second feedback packet can be a signal strength packet as defined in the Qi standard, but this is merely one implementation. It should be noted that the feedback signal used to obtain information about the received power strength can vary depending on the wireless power transmission standard applied to the wireless power transmitter.

[0285] The wireless power transmitter can determine whether the information regarding the received power strength included in the second feedback packet is a normal value (S1503). For the method of determining whether the information regarding the received power strength is normal, please refer to the description of the above figures.

[0286] When it is determined that the information about the received power strength is abnormal, the wireless power transmitter can use a predetermined offset to correct the received power strength (S1504).

[0287] The wireless power transmitter can calculate the path loss PL (S1505) based on the current transmitted power strength and received power strength (or the corrected received power strength).

[0288] The wireless power transmitter can determine whether the calculated path loss value exceeds the path loss threshold (S1506).

[0289] When the calculated path loss value exceeds the path loss threshold, the wireless power transmitter can determine that a foreign object is placed on the wireless power transmission path (S1507). At this time, the wireless power transmitter can output a predetermined warning alarm through the alarm unit set therein, and then enter the selection phase.

[0290] When the calculated path loss value is determined to be less than the path loss threshold in step 1506, the wireless power transmitter can determine that there is no foreign object in the wireless power transmission path (S1508). Due to errors in internal circuit components, installed software, or sensors, the wireless power receiver can determine that power with a strength lower than the actual received power is being received. If the received power strength is not corrected, the path loss can have a very large value, so the wireless power transmitter can determine that a foreign object is present even if there is no foreign object in the wireless power transmission path.

[0291] As described above, in this embodiment, by determining whether the information about the received power strength is normal and adaptively correcting the received power strength based on the determination result, power transmission can be prevented from being interrupted.

[0292] Furthermore, in this embodiment, by correcting the received power intensity when it is abnormal compared to the transmitted power intensity in a fixed-frequency wireless power transmitter, foreign objects can be detected more accurately.

[0293] Figure 16 This is a block diagram illustrating the configuration of a foreign object detection device according to an embodiment.

[0294] The foreign object detection device 1600 according to this embodiment can be configured as a measuring device for certifying wireless power transmission devices or wireless power receiving devices.

[0295] Reference Figure 16 The foreign object detection device 1600 may include: a demodulator 1610, an adjuster 1620, a resonant unit 1630, a determination unit 1640, a correction unit 1650, a detector 1660, and a controller 1670. In the following description, some components of the foreign object detection device 1600 may be integrated into at least one microprocessor, and other components may be configured in the form of circuit elements, sensors, integrated circuits, etc. For example, the resonant unit 1630 may be... Figure 11 The resonant circuit 1130 and the regulator 1620 may include at least one of a DC-DC converter 1110 or an inverter 1120. Additionally, the demodulator 1610 may include at least one of a frequency filter, an amplifier, or an integrator for wireless signal processing, and may be implemented in the form of an ASIC and / or a digital signal processor (DSP), but is not limited thereto.

[0296] The controller 1670 can control the overall operation and input / output of the foreign object detection device 1600.

[0297] When a wireless signal transmitted by the wireless power receiver is received through an antenna (or transmission coil) disposed therein, the demodulator 1610 can demodulate the wireless signal and transmit the demodulated packets to the controller 1670. For example, the demodulator 1610 can demodulate received feedback packets for power control, i.e., control error packets, and predetermined packets, such as signal strength packets, for feedback of the strength information of the wireless power signal received by the wireless power receiver during power transmission, and transmit the demodulated packets to the controller 1670.

[0298] The regulator 1620 can dynamically adjust the intensity of the power transmitted through the resonant unit 1630 based on feedback groups used for requesting power control.

[0299] The resonant unit 1630 may include a resonant circuit for wirelessly transmitting AC power signals of a specific frequency.

[0300] The determining unit 1640 can determine whether information received from the wireless power receiver, such as information about the received power strength, is normal.

[0301] For example, the determining unit 1640 can compare a received power strength threshold determined corresponding to the current charging mode with the received power strength to determine whether the received information is normal. Specifically, when the received power strength is less than the received power strength threshold, the determining unit 1640 can determine that the information regarding the received power strength obtained from the receiver is abnormal.

[0302] In another example, the determining unit 1640 can determine whether the received information is normal based on the ratio of the received power strength to the current transmitted power strength. Specifically, when the value obtained by dividing the received power strength value by the current transmitted power strength is less than a predetermined ratio threshold, the determining unit 1640 can determine that the information regarding the received power strength obtained from the receiver is abnormal.

[0303] When the determining unit 1640 determines that the received information is abnormal, the correction unit 1650 can use a predetermined offset to correct the received power strength. For example, when the acquired information about the received power strength is abnormal, the correction unit 1650 can add an offset to the received power strength value to calculate the corrected received power strength value. Here, the offset can be dynamically determined based on at least one of the following: charging mode, current transmitted power strength, type of transmitter installed in the foreign object detection device, or type of receiver; however, this is only one implementation. A specific fixed value can be used as the offset.

[0304] The detector 1660 can calculate path loss based on the current transmitted power strength and the received power strength (or the corrected received power strength). For example, the path loss can be calculated as the difference between the current transmitted power strength and the received power strength.

[0305] The detector 1660 can compare the calculated path loss with a path loss threshold (or a threshold range) to determine the presence of a foreign object. For example, if the calculated path loss is greater than the path loss threshold, it is determined that a foreign object has been placed on the wireless power transmission path.

[0306] Additionally, detector 1660 can determine a quality factor threshold based on foreign object detection state groups received during the negotiation phase, and compare the quality factor threshold with a quality factor value measured after object detection and before entering the detection phase to determine whether a foreign object is present.

[0307] Although in the above embodiment, detector 1660 performs a foreign object detection procedure based on path loss and a foreign object detection procedure based on quality factor, this is merely an embodiment and various foreign object detection procedures defined by those skilled in the art can be performed in addition.

[0308] The operation and function of the components of the foreign object detection device 1600 may also include the components and functions disclosed in the description of the above figures.

[0309] In the above embodiments, although the wireless power transmitter (or foreign object detection device) corrects for the received power strength and determines the presence of a foreign object when the information about the received power strength included in the feedback packet is abnormal, this is merely one embodiment. When the information about the received power strength is abnormal, the wireless power transmitter (or foreign object detection device) according to another embodiment can terminate the foreign object detection procedure based on path loss and execute a foreign object detection procedure based on the quality factor.

[0310] For example, if abnormal information about the received power strength is determined during a path loss-based foreign object detection procedure in the power transmission phase, the wireless power transmitter (or foreign object detection device) can temporarily stop power transmission and enter a negotiation phase to execute a quality factor-based foreign object detection procedure.

[0311] Figure 17 This is a flowchart illustrating a foreign object detection method according to an embodiment.

[0312] Reference Figure 17 The foreign object detection device may not execute the foreign object detection procedure based on the quality factor value in the negotiation phase, and may enter the power transmission phase to start the foreign object detection procedure based on path loss (S1701).

[0313] During charging, the foreign object detection device can periodically receive feedback packets including information about the received power intensity (S1702).

[0314] The foreign object detection device can determine whether the information about the received power intensity is normal (S1703).

[0315] When the information is determined to be normal, the foreign object detection device can calculate the path loss based on the current transmitted power intensity and received power intensity, and compare the calculated path loss with a predetermined path loss threshold to determine whether there is a foreign object (S1705 to S1706).

[0316] When it is determined in step 1703 that the information is abnormal, the foreign object detection device can temporarily stop power transmission and execute a foreign object detection procedure based on the quality factor value.

[0317] For example, in Figure 17 The method described in the implementation of switching the foreign object detection program based on whether the information about the received power intensity is normal is applicable to cases where the charging mode set according to the wireless power receiver is fast charging mode, but is not limited thereto, and regardless of the charging mode, this method is applicable to cases where the charging mode set according to the wireless power receiver is fast charging mode.

[0318] Therefore, in this embodiment, by adaptively switching the foreign object detection program based on whether the information about the received power intensity is normal, foreign objects can be detected more accurately.

[0319] Although in the above embodiment, the switching to the foreign object detection procedure based on the quality factor is described as being performed when it is determined that the information about the received power strength is abnormal during the foreign object detection procedure based on path loss in the power transmission phase, this is only one embodiment, and it is also possible to switch to another foreign object detection procedure separately defined according to the design of those skilled in the art or to another foreign object detection procedure defined in the wireless power transmission standard.

[0320] The method according to the foregoing embodiments can be implemented as code that can be written to a computer-readable recording medium and thus can be read by a computer. Examples of computer-readable recording media include ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage device, and carrier wave (e.g., data transmission via the Internet).

[0321] Computer-readable recording media can be distributed across multiple computer systems connected to a network, allowing computer-readable code to be written into and executed from them in a distributed manner. Those skilled in the art will understand the functional programs, code, and code segments required to implement the embodiments described herein.

[0322] Those skilled in the art will understand that this disclosure may be implemented in other specific ways besides those set forth herein without departing from the spirit and essential characteristics of this disclosure.

[0323] Therefore, the exemplary embodiments described above should be interpreted in all respects as illustrative rather than restrictive. The scope of this disclosure should be determined by the appended claims and their legal equivalents, not by the foregoing description, and all variations falling within the meaning and scope of the appended claims are intended to be included in the appended claims.

[0324] [Industrial Applicability]

[0325] The implementation relates to wireless power transmission technology and is applicable to wireless power transmitters that use a resonant circuit disposed therein to wirelessly transmit power to a wireless power receiver.

Claims

1. A wireless power transmission method for a wireless power transmitter, the wireless power transmission method comprising: Before power transmission, a foreign object detection procedure based on the quality factor value is performed; as well as During power transmission, a foreign object detection procedure based on path loss is executed. The foreign object detection procedure based on the quality factor includes: The quality factor of the storage resonant circuit is measured. Receive foreign object detection status packets including reference quality factor values; Determine the quality factor threshold based on the reference quality factor value; and The measured quality factor value is compared with the quality factor threshold to determine whether foreign matter is present. The foreign object detection program based on path loss includes: The path loss is calculated based on the transmitted and received power strength; and The calculated path loss is compared with a path loss threshold to determine if foreign objects are present. The path loss threshold is determined proportionally to the current transmitted power intensity, or dynamically based on the current transmitted power intensity. Specifically, a foreign object detection procedure based on quality factor is executed before the foreign object detection procedure based on path loss.

2. The wireless power transmission method according to claim 1, wherein, The received power intensity is included and contained in the periodic feedback packets during the power transmission phase.

3. The wireless power transmission method according to claim 2, wherein, Foreign object detection programs based on path loss include: Determine a first threshold indicating the maximum received signal strength corresponding to the current transmitted power intensity that can be received by the wireless power receiver; and When the received power intensity exceeds the first threshold, it is determined that the received power intensity is abnormal.

4. The wireless power transmission method according to claim 3, wherein, Foreign object detection programs based on path loss also include: When it is determined that the received power intensity is abnormal, the received power intensity is corrected. The correction of the received power intensity includes: Determine the offset value based on the current transmitted power intensity; and The offset value is subtracted from the received power intensity to correct the received power intensity.

5. The wireless power transmission method according to claim 1, in, When a foreign object is detected in at least one of a foreign object detection procedure based on quality factor or a foreign object detection procedure based on path loss, it is finally determined that a foreign object has been detected.

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