Wireless charging method and device therefor

Abstract

To provide a wireless charging method that accurately determines foreign substances and prevents heat generation phenomena, reduction in charging efficiency, and waste of power consumption and a device for the same.SOLUTION: In the wireless charging system, a wireless charging method by means of a wireless power transmitter includes stages for sensing an object in a charging area by using an analogue ping of very short pulses, measuring a Q-value (Quality Factor Value), receiving information including a reference Q-value, detecting a foreign matter by using the measured Q-value and the reference Q-value, and transmitting a response signal including ACK or NAK information, depending on whether foreign matter has been detected. The wireless power transmitter transmits information including a first guaranteed power value (guaranteed power value) when the response signal contains ACK information and transmits information including a second guaranteed power value, which is the minimum guaranteed power when the response signal contains NAK information. The first guaranteed power value is greater than the second guaranteed power value.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to wireless power transmission technology, and particularly to a wireless charging method and an apparatus therefor.

Background Art

[0002] Portable terminals such as mobile phones and notebook computers include a battery for storing power and a circuit for charging and discharging. In order to charge the battery of such a terminal, power must be supplied from an external charger.

[0003] Generally, as an example of an electrical connection method between a charging device for charging a battery and the battery, power is supplied from a commercial power supply and converted into a voltage and current corresponding to the battery, and electrical energy is supplied to the battery through the terminals of the battery. A terminal supply method can be cited. Such a terminal supply method involves the use of a physical cable or wire. Therefore, when handling a large number of terminal supply method equipment, many cables occupy a considerable working space and are difficult to organize, and the appearance is not good either. In addition, the terminal supply method may cause problems such as an instantaneous discharge phenomenon due to a different potential difference between terminals, burning and fire caused by foreign substances, natural discharge, and a decrease in the life and performance of the battery.

[0004] Recently, in order to solve such problems, a charging system (hereinafter referred to as a "wireless charging system") and a control method using a method of wirelessly transmitting power have been presented. In addition, the wireless charging system has not been basically equipped in some portable terminals in the past, and consumers need to separately Since it was necessary to separately purchase the wireless charging receiver accessory, the demand for the wireless charging system was low. However, it is expected that the number of wireless charging users will increase rapidly, and in the future, terminal manufacturers are also expected to basically equip their devices with wireless charging functions.

[0005] Generally, a wireless charging system consists of a wireless power transmitter that supplies electrical energy by a wireless power transmission method and a wireless power receiver that receives the electrical energy supplied from the wireless power transmitter and charges a battery. The wireless charging system can transmit power by at least one wireless power transmission method (for example, electromagnetic induction method, electromagnetic resonance method, RF wireless power transmission method, etc.). It is composed of a wireless power receiver that receives the electrical energy supplied from the wireless power transmitter and charges the battery.

[0006] As an example, the wireless power transmission method can charge by using the principle of electromagnetic induction in which a magnetic field is generated from a power transmitter coil and electricity is induced in a receiving coil by the influence of the magnetic field. Based on this, various wireless power transmission standards are used. Here, the wireless power transmission standards of the electromagnetic induction method can include the wireless charging technologies of the electromagnetic induction method defined by the Wireless Power Consortium (WPC) and the Air Fuel Alliance (formerly PMA, Power Matters Alliance).

[0007] As another example, the wireless power transmission method may use the electromagnetic resonance method in which the magnetic field generated by the transmission coil of the wireless power transmitter is transmitted to a wireless power receiver located at a short distance in synchronization with a specific resonance frequency. Here, the electromagnetic resonance method

[0008] As another example, the wireless power transmission method may use the electromagnetic resonance (Electromagnetic Resonance) method in which the magnetic field generated by the transmission coil of the wireless power transmitter is transmitted to a wireless power receiver located at a short distance in synchronization with a specific resonance frequency. Here, the electromagnetic resonance ​​​​​The method can include the wireless charging technology of the resonance method defined by the Air Fuel Alliance (formerly A4WP, Alliance for Wireless Power), a standard organization of wireless charging technology.

[0009] As another example, the wireless power transmission method may use the RF wireless power transmission method that transmits power to a wireless power receiver located at a long distance by superimposing low-power energy on an RF signal.

[0010] On the other hand, when there is a foreign substance that absorbs a magnetic field such as metal between the wireless power transmitter and the wireless power receiver in the wireless charging system, problems such as heat generation, reduction of charging efficiency, and increase of power consumption occur. Therefore, an accurate foreign substance detection method is required.

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0011] The present invention has been devised to solve the problems of the above-described conventional technologies, and an object of the present invention is to provide a wireless charging method, an apparatus and a system therefor.

[0012] Furthermore, a further object of the present invention is to provide a wireless charging method for accurately determining a foreign substance, and an apparatus and a system therefor.

[0013] Furthermore, a further object of the present invention is to provide a wireless charging method, an apparatus and a system therefor that solve the problem that wireless charging cannot be performed due to a misrecognition that a foreign substance exists in the conventional case.

[0014] The technical problems to be solved by the present invention are not limited to the technical problems mentioned above, and ​​​​​​​​Another technical problem that has not been addressed should be clearly understood by those with ordinary knowledge in the technical field to which the present invention belongs from the following description. by those having ordinary knowledge in the technical field to which the present invention pertains.

Means for Solving the Problem

[0015] In order to solve the above technical problems, the wireless charging method according to the embodiment is a wireless charging method in a wireless power transmitter that wirelessly transmits power to a wireless power receiver, including: a step of sensing an object in a charging area; a step of measuring a Q value (Quality Factor Value); a step of receiving information including a reference Q value; a step of detecting a foreign substance using the measured Q value and the reference Q value; a step of transmitting information including a first guaranteed power value when the foreign substance is not detected; and a step of transmitting information including a second guaranteed power value when the foreign substance is detected, wherein the first guaranteed power value may be greater than the second guaranteed power value. Further, the wireless charging method according to the embodiment includes a step of measuring the internal temperature of the wireless power transmitter, and when the sensed temperature is less than a preset temperature during a preset period when the foreign substance is detected, further includes a step of transmitting guaranteed power having a third guaranteed power value, and the third guaranteed power value may be greater than the second guaranteed power value. Further, in the wireless charging method according to the embodiment, the second guaranteed power value may be the lowest guaranteed power of the wireless power transmitter.

[0016] Further, in the wireless charging method according to the embodiment, the step of detecting the foreign substance includes a step of determining a critical Q value using the reference Q value, and if the measured Q value is greater than or equal to the critical Q value, it is determined that there is no foreign substance, and if the measured Q value is less than the critical Q value, it is determined that a foreign substance is present. Further, the wireless charging method according to the embodiment may further include a step of transmitting guaranteed power having a third guaranteed power value when the sensed temperature is less than a preset temperature during a preset period when the foreign substance is detected,

[0017] wherein the third guaranteed power value may be greater than the second guaranteed power value. Further, in the wireless charging method according to the embodiment, the second guaranteed power value may be the lowest guaranteed power of the wireless power transmitter.

[0018] Further, in the wireless charging method according to the embodiment, the step of detecting the foreign substance includes a step of determining a critical Q value using the reference Q value, and if the measured Q value is greater than or equal to the critical Q value, it is determined that there is no foreign substance, and if the measured Q value is less than the critical Q value, If it is determined that no substance is detected and the measured Q value is less than the critical Q value, it is different It can include determining the stage of determining that a substance is detected.

[0019] Also, in the wireless charging method according to the embodiment, the critical Q value may be a value obtained by reducing the reference Q value by 10%.

[0020] Also, in the wireless charging method according to the embodiment, when the foreign substance is detected, it further includes determining whether to perform wireless charging. When it is determined to perform wireless charging, information including a second guaranteed power value is transmitted. When it is determined not to perform wireless charging, wireless charging can be aborted.

[0021] Also, in the wireless charging method according to the embodiment, when the foreign substance is detected, the stage of determining whether to perform wireless charging includes determining an allowable Q value using the critical Q value, and if the measured Q value is greater than or equal to the allowable Q value, it is determined to perform wireless charging. If the measured Q value is less than the allowable Q value, it is determined not to perform wireless charging.

[0022] Also, in the wireless charging method according to the embodiment, the allowable Q value may be a value obtained by reducing the critical Q value by 20%.

[0023] Also, in the wireless charging method according to the embodiment, when the sensed temperature is less than a preset temperature during a preset period, the stage of transmitting guaranteed power having a third guaranteed power value can be performed in a renegotiation stage.

[0024] Also, in the wireless charging method according to the embodiment, when the foreign substance is not detected, the first guaranteed power ​​​​​​​​​​​When information including a force value is transmitted, a correction stage is executed and the process proceeds to the power transmission stage. When the foreign substance is detected, when information including a second guaranteed power value is transmitted, the process can proceed to the power transmission stage without executing the correction stage.

[0025] The wireless charging method according to the embodiment is a wireless charging method in a wireless power transmitter that wirelessly transmits power to a wireless power receiver. In the wireless charging method, a stage of sensing an object in a charging area, a stage of measuring a Q value, a stage of receiving information including a reference Q value, a stage of determining whether the reference Q value is less than 50, and when the reference Q value is less than 50, performing a first foreign substance detection using the measured Q value and the reference Q value. If the reference Q value is 50 or more, performing a second foreign substance detection using the measured Q value and the reference Q value. When the foreign substance is not detected through the first foreign substance detection, transmitting information including a first guaranteed power value. When the foreign substance is detected, transmitting information including a second guaranteed power value. When the foreign substance is not detected through the second foreign substance detection, transmitting information including a first guaranteed power value. When the foreign substance is detected, stopping wireless charging. The first guaranteed power value may be greater than the second guaranteed power value.

[0026] Also, the wireless charging method according to the embodiment includes a stage of measuring the internal temperature of the wireless power transmitter. When the foreign substance is detected through the first foreign substance detection, if the sensed temperature is less than a preset temperature for a preset time, further including a stage of transmitting guaranteed power having a third guaranteed power value. The third guaranteed power value may be greater than the second guaranteed power value.

[0027] ​​​The wireless charging device according to the embodiment includes one or more transmission coils and DC power applied from the outside. A power conversion unit that converts the intensity of the power, a communication unit that exchanges information with an external device, and a sensing unit that measures the Q value. A control unit that receives information including a reference Q value through the communication unit and performs foreign substance detection. The control unit detects a foreign substance using the measured Q value and the reference Q value. When no foreign substance is detected, the control unit transmits information including a first guaranteed power value. When a foreign substance is detected, the control unit transmits information including a second guaranteed power value. The first guaranteed power value may be greater than the second guaranteed power value. When no foreign substance is detected, the control unit transmits information including a first guaranteed power value. When a foreign substance is detected, the control unit transmits information including a second guaranteed power value. The first guaranteed power value may be greater than the second guaranteed power value. When a foreign substance is detected, the control unit transmits information including a second guaranteed power value. The first guaranteed power value may be greater than the second guaranteed power value. The first guaranteed power value may be greater than the second guaranteed power value.

[0028] Also, in the wireless charging device according to the embodiment, the sensing unit measures the internal temperature of the wireless power transmitter. When a foreign substance is detected, if the sensed temperature is less than a preset temperature during a preset period, the control unit transmits a guaranteed power having a third guaranteed power value. The third guaranteed power value may be greater than the second guaranteed power value. When a foreign substance is detected, if the sensed temperature is less than a preset temperature during a preset period, the control unit transmits a guaranteed power having a third guaranteed power value. The third guaranteed power value may be greater than the second guaranteed power value. When a foreign substance is detected, if the sensed temperature is less than a preset temperature during a preset period, the control unit transmits a guaranteed power having a third guaranteed power value. The third guaranteed power value may be greater than the second guaranteed power value. The third guaranteed power value may be greater than the second guaranteed power value.

[0029] Also, in the wireless charging device according to the embodiment, the second guaranteed power value may be the lowest guaranteed power of the wireless power transmitter. The second guaranteed power value may be the lowest guaranteed power of the wireless power transmitter.

[0030] Also, in the wireless charging device according to the embodiment, for the foreign substance detection, the control unit determines a critical Q value using the reference Q value. If the measured Q value is greater than or equal to the critical Q value, it is determined that no foreign substance is detected. If the measured Q value is less than the critical Q value, it can be determined that a foreign substance is detected. For the foreign substance detection, the control unit determines a critical Q value using the reference Q value. If the measured Q value is greater than or equal to the critical Q value, it is determined that no foreign substance is detected. If the measured Q value is less than the critical Q value, it can be determined that a foreign substance is detected. If the measured Q value is greater than or equal to the critical Q value, it is determined that no foreign substance is detected. If the measured Q value is less than the critical Q value, it can be determined that a foreign substance is detected. If the measured Q value is greater than or equal to the critical Q value, it is determined that no foreign substance is detected. If the measured Q value is less than the critical Q value, it can be determined that a foreign substance is detected.

[0031] Also, in the wireless charging device according to the embodiment, the critical Q value may be a value obtained by reducing the reference Q value by 10%. The critical Q value may be a value obtained by reducing the reference Q value by 10%.

[0032] In addition, in the wireless charging device according to the embodiment, when the foreign substance is detected, the control unit determines whether to perform wireless charging. When it is determined to perform wireless charging, information including a second guaranteed power value is transmitted. When it is determined not to perform wireless charging, wireless charging can be aborted. .

[0033] In addition, in the wireless charging device according to the embodiment, when the foreign substance is detected, the determination of whether to perform wireless charging is made by the control unit determining an allowable Q value using the critical Q value. If the measured Q value is greater than or equal to the allowable Q value, it is determined to perform wireless charging. If the measured Q value is less than the allowable Q value, it can be determined not to perform wireless charging.

[0034] In addition, in the wireless charging device according to the embodiment, the allowable Q value may be a value obtained by reducing the critical Q value by 20%.

[0035] In addition, in the wireless charging device according to the embodiment, during the preset period, when the sensed temperature is lower than the preset temperature, the stage of transmitting guaranteed power having a third guaranteed power value can be performed in the renegotiation stage.

[0036] In addition, in the wireless charging device according to the embodiment, when no foreign substance is detected, when the control unit transmits information including a first guaranteed power value, a correction stage is executed and the process proceeds to the power transmission stage. When a foreign substance is detected, when the control unit transmits information including a second guaranteed power value, the process can proceed to the power transmission stage without executing the correction stage.

[0037] The wireless charging device according to the embodiment includes one or more transmitting coils and DC power applied from the outside. ​​​​​​​​A power conversion unit that converts the intensity, a communication unit that exchanges information with an external device, and a sensing unit that measures a Q value. A control unit that receives information including a reference Q value through the communication unit and determines whether the reference Q value is less than 50. The control unit, when the reference Q value is less than 50, performs first foreign substance detection using the measured Q value and the reference Q value. When the reference Q value is 50 or more, second foreign substance detection is performed using the measured Q value and the reference Q value. The control unit, when the foreign substance is not detected through the first foreign substance detection, transmits information including a first guaranteed power value. When the foreign substance is detected, it transmits information including a second guaranteed power value. When the foreign substance is not detected through the second foreign substance detection, it transmits information including a first guaranteed power value. When the foreign substance is detected, wireless charging is stopped. The first guaranteed power value may be greater than the second guaranteed power value. Also, in the wireless charging device according to the embodiment, the sensing unit measures the internal temperature of the wireless power transmitter. The control unit, when the foreign substance is detected through the first foreign substance detection and the sensed temperature is less than a preset temperature during a preset period, transmits a guaranteed power having a third guaranteed power value. The third guaranteed power value may be greater than the second guaranteed power value. In the wireless charging method according to the embodiment, in the wireless charging method in a wireless power transmitter that wirelessly transmits power to a wireless power receiver, before the ping phase, there is a step of measuring a Q value, a step of receiving an FOD status packet including a reference Q value in the negotiation phase, and using the reference Q value.

[0038]

[0039] ​​​​​​​​​​determining a critical Q value; determining a tolerance Q value using the critical Q value; and detecting a first foreign substance based on the measured Q value and the tolerance Q value. This is possible.

[0040] Also, in the wireless charging method according to the embodiment, the critical Q value may be a value obtained by reducing the reference Q value by 10%, and the tolerance Q value may be a value obtained by reducing the critical Q value by 20%.

[0041] Also, in the wireless charging method according to the embodiment, the step of detecting the first foreign substance may determine whether the measured Q value is greater than or equal to the tolerance Q value.

[0042] Also, in the wireless charging method according to the embodiment, if the measured Q value is greater than or equal to the tolerance Q value, the method may further include transmitting an ACK for performing wireless charging.

[0043] Also, in the wireless charging method according to the embodiment, the method may further include determining whether the measured Q value is greater than or equal to the critical Q value, and after transitioning to a correction step, if the measured Q value is greater than or equal to the critical Q value, performing correction, and if the measured Q value is less than the critical Q value, not performing correction.

[0044] Also, in the wireless charging method according to the embodiment, after transitioning to a power transmission step, the method may further include performing second foreign substance detection.

[0045] Also, in the wireless charging method according to the embodiment, the second foreign substance detection may determine that a foreign substance is present when a power loss value determined based on a received power value and a transmitted power value exceeds a predetermined critical power loss value.

[0046] In addition, in the wireless charging method according to the embodiment, in the second foreign substance detection, when the measured internal temperature value exceeds a predetermined critical temperature value, it can be determined that a foreign substance is present.

[0047] In addition, in the wireless charging method according to the embodiment, the FOD status packet further includes a reference frequency value. Before the ping stage, a stage of measuring a frequency value, a stage of determining a critical frequency value using the reference frequency value in the negotiation stage, and a stage of determining an allowable frequency value using the critical frequency value are further included. The stage of detecting the first foreign substance can be based on the measured frequency value and the allowable frequency value. In addition, in the wireless charging method according to the embodiment, the critical frequency value is a value increased by 10% of the reference frequency value, and the allowable frequency value may be a value increased by 20% of the critical frequency. In addition, in the wireless charging method according to the embodiment, the stage of detecting the first foreign substance can determine whether the measured frequency value is less than or equal to the allowable frequency value.

[0048] In addition, in the wireless charging method according to the embodiment, the critical frequency value is a value increased by 10% of the reference frequency value, and the allowable frequency value may be a value increased by 20% of the critical frequency. In addition, in the wireless charging method according to the embodiment, the stage of detecting the first foreign substance can determine whether the measured frequency value is less than or equal to the allowable frequency value. It may be.

[0049] In addition, in the wireless charging method according to the embodiment, the stage of detecting the first foreign substance can determine whether the measured frequency value is less than or equal to the allowable frequency value. If the measured frequency value is less than or equal to the allowable frequency value, a stage of transmitting an ACK for performing wireless charging can be further included.

[0050] In addition, in the wireless charging method according to the embodiment, a stage of determining whether the measured frequency value is less than or equal to the critical frequency value, and after shifting to the correction stage, if the measured frequency value is less than or equal to the critical frequency value, correction is executed, and if the measured frequency value exceeds the critical frequency value, a stage of not executing correction can be further included. If the measured frequency value is less than or equal to the allowable frequency value, a stage of transmitting an ACK for performing wireless charging can be further included.

[0051] In addition, in the wireless charging method according to the embodiment, a stage of determining whether the measured frequency value is less than or equal to the critical frequency value, and after shifting to the correction stage, if the measured frequency value is less than or equal to the critical frequency value, correction is executed, and if the measured frequency value exceeds the critical frequency value, a stage of not executing correction can be further included. After shifting to the correction stage, if the measured frequency value is less than or equal to the critical frequency value, correction is executed, and if the measured frequency value exceeds the critical frequency value, a stage of not executing correction can be further included. If the measured frequency value is less than or equal to the critical frequency value, correction is executed, and if the measured frequency value exceeds the critical frequency value, a stage of not executing correction can be further included. If the measured frequency value exceeds the critical frequency value, a stage of not executing correction can be further included.

[0052] In addition, the wireless charging method according to the embodiment is such that the FOD state packet further includes a reference frequency value, and includes a step of measuring an equivalent series resistance value before the ping stage, a step of determining a critical equivalent series resistance value by using the reference Q value and the reference frequency value in the negotiation stage, and a step of determining an allowable equivalent series resistance value by using the critical equivalent series resistance value. The step of detecting the first foreign substance can be based on the measured equivalent series resistance value and the allowable equivalent series resistance value. In addition, the wireless charging method according to the embodiment is such that the FOD state packet further includes a reference frequency value, and includes a step of measuring an equivalent series resistance value before the ping stage, a step of determining a critical equivalent series resistance value by using the reference Q value and the reference frequency value in the negotiation stage, and a step of determining an allowable equivalent series resistance value by using the critical equivalent series resistance value. The step of detecting the first foreign substance can be based on the measured equivalent series resistance value and the allowable equivalent series resistance value. In addition, the wireless charging method according to the embodiment is such that the FOD state packet further includes a reference frequency value, and includes a step of measuring an equivalent series resistance value before the ping stage, a step of determining a critical equivalent series resistance value by using the reference Q value and the reference frequency value in the negotiation stage, and a step of determining an allowable equivalent series resistance value by using the critical equivalent series resistance value. The step of detecting the first foreign substance can be based on the measured equivalent series resistance value and the allowable equivalent series resistance value. In addition, the wireless charging method according to the embodiment is such that the FOD state packet further includes a reference frequency value, and includes a step of measuring an equivalent series resistance value before the ping stage, a step of determining a critical equivalent series resistance value by using the reference Q value and the reference frequency value in the negotiation stage, and a step of determining an allowable equivalent series resistance value by using the critical equivalent series resistance value. The step of detecting the first foreign substance can be based on the measured equivalent series resistance value and the allowable equivalent series resistance value. In addition, the wireless charging method according to the embodiment is such that the FOD state packet further includes a reference frequency value, and includes a step of measuring an equivalent series resistance value before the ping stage, a step of determining a critical equivalent series resistance value by using the reference Q value and the reference frequency value in the negotiation stage, and a step of determining an allowable equivalent series resistance value by using the critical equivalent series resistance value. The step of detecting the first foreign substance can be based on the measured equivalent series resistance value and the allowable equivalent series resistance value. In addition, the wireless charging method according to the embodiment is such that the FOD state packet further includes a reference frequency value, and includes a step of measuring an equivalent series resistance value before the ping stage, a step of determining a critical equivalent series resistance value by using the reference Q value and the reference frequency value in the negotiation stage, and a step of determining an allowable equivalent series resistance value by using the critical equivalent series resistance value. The step of detecting the first foreign substance can be based on the measured equivalent series resistance value and the allowable equivalent series resistance value.

[0053] In addition, the wireless charging method according to the embodiment is such that the critical equivalent series resistance value is a value increased by 10% of the reference equivalent series resistance value, and the allowable equivalent series resistance value may be a value increased by 20% of the critical equivalent series resistance value. In addition, the wireless charging method according to the embodiment is such that the critical equivalent series resistance value is a value increased by 10% of the reference equivalent series resistance value, and the allowable equivalent series resistance value may be a value increased by 20% of the critical equivalent series resistance value. In addition, the wireless charging method according to the embodiment is such that the critical equivalent series resistance value is a value increased by 10% of the reference equivalent series resistance value, and the allowable equivalent series resistance value may be a value increased by 20% of the critical equivalent series resistance value.

[0054] In addition, the wireless charging method according to the embodiment is such that the step of detecting the first foreign substance can determine whether the measured equivalent series resistance value is less than or equal to the allowable equivalent series resistance value. In addition, the wireless charging method according to the embodiment is such that the step of detecting the first foreign substance can determine whether the measured equivalent series resistance value is less than or equal to the allowable equivalent series resistance value.

[0055] In addition, the wireless charging method according to the embodiment may further include a step of transmitting an ACK for performing wireless charging if the measured equivalent series resistance value is less than or equal to the allowable equivalent series resistance value. In addition, the wireless charging method according to the embodiment may further include a step of transmitting an ACK for performing wireless charging if the measured equivalent series resistance value is less than or equal to the allowable equivalent series resistance value. In addition, the wireless charging method according to the embodiment may further include a step of transmitting an ACK for performing wireless charging if the measured equivalent series resistance value is less than or equal to the allowable equivalent series resistance value.

[0056] In addition, the wireless charging method according to the embodiment further includes a step of determining whether the measured equivalent series resistance value is less than or equal to the critical equivalent series resistance value, and after transitioning to the correction stage, if the measured equivalent series resistance value is less than or equal to the critical equivalent series resistance value, performing correction, and if the measured equivalent series resistance value exceeds the critical equivalent series resistance value, not performing correction. In addition, the wireless charging method according to the embodiment further includes a step of determining whether the measured equivalent series resistance value is less than or equal to the critical equivalent series resistance value, and after transitioning to the correction stage, if the measured equivalent series resistance value is less than or equal to the critical equivalent series resistance value, performing correction, and if the measured equivalent series resistance value exceeds the critical equivalent series resistance value, not performing correction. In addition, the wireless charging method according to the embodiment further includes a step of determining whether the measured equivalent series resistance value is less than or equal to the critical equivalent series resistance value, and after transitioning to the correction stage, if the measured equivalent series resistance value is less than or equal to the critical equivalent series resistance value, performing correction, and if the measured equivalent series resistance value exceeds the critical equivalent series resistance value, not performing correction. In addition, the wireless charging method according to the embodiment further includes a step of determining whether the measured equivalent series resistance value is less than or equal to the critical equivalent series resistance value, and after transitioning to the correction stage, if the measured equivalent series resistance value is less than or equal to the critical equivalent series resistance value, performing correction, and if the measured equivalent series resistance value exceeds the critical equivalent series resistance value, not performing correction. In addition, the wireless charging method according to the embodiment further includes a step of determining whether the measured equivalent series resistance value is less than or equal to the critical equivalent series resistance value, and after transitioning to the correction stage, if the measured equivalent series resistance value is less than or equal to the critical equivalent series resistance value, performing correction, and if the measured equivalent series resistance value exceeds the critical equivalent series resistance value, not performing correction.

[0057] The wireless charging device according to the embodiment includes one or more transmitting coils, DC power applied from the outside a power conversion unit that converts the intensity of, a communication unit that exchanges information with an external device, and a Q value measuring sensor unit, and a control unit that receives an FOD state packet including a reference Q value through the communication unit and performs detection of a first foreign substance, wherein the control unit determines a critical Q value using the reference Q value, determines a tolerance Q value using the critical Q value, and the first foreign substance detection can be based on the measured Q value and the tolerance Q value.

[0058] Also, in the wireless charging device according to the embodiment, the critical Q value is a value obtained by reducing the reference Q value by 10%, and the tolerance Q value may be a value obtained by reducing the critical Q value by 20%.

[0059] Also, in the wireless charging device according to the embodiment, the first foreign substance detection can be performed by the control unit determining whether the measured Q value is greater than or equal to the tolerance Q value.

[0060] Also, in the wireless charging device according to the embodiment, if the measured Q value is greater than or equal to the tolerance Q value, the control unit can transmit an ACK for performing wireless charging.

[0061] Also, in the wireless charging device according to the embodiment, after transitioning to the correction stage, if the measured Q value is greater than or equal to the critical Q value, the control unit performs correction, and if the measured Q value is less than the critical Q value, correction may not be performed.

[0062] Also, in the wireless charging device according to the embodiment, after transitioning to the power transmission stage, the control unit can perform detection of a second foreign substance.

[0063] In addition, for the wireless charging device according to the embodiment, in the second foreign substance detection, when the power loss value determined by the control unit based on the received power value and the transmitted power value exceeds a predetermined critical power loss value, it can be determined that a foreign substance exists.

[0064] In addition, for the wireless charging device according to the embodiment, in the second foreign substance detection, when the internal temperature value measured by the control unit exceeds a predetermined critical temperature value, it can be determined that a foreign substance exists.

[0065] In addition, for the wireless charging device according to the embodiment, the FOD status packet further includes a reference frequency value, the sensing unit measures the frequency value, and the control unit determines a critical frequency value using the reference frequency value, determines an allowable frequency value using the critical frequency value, and the first foreign substance detection can be based on the measured frequency value and the allowable frequency value. to the sensing unit measures the frequency value, and the control unit determines a critical frequency value using the reference frequency value, determines an allowable frequency value using the critical frequency value, and the first foreign substance detection can be based on the measured frequency value and the allowable frequency value. using the reference frequency value, determines an allowable frequency value using the critical frequency value, and the first foreign substance detection can be based on the measured frequency value and the allowable frequency value. In addition, for the wireless charging device according to the embodiment, the critical frequency value may be a value increased by 10% of the reference frequency value, and the allowable frequency value may be a value increased by 20% of the critical frequency.

[0066] In addition, for the wireless charging device according to the embodiment, the critical frequency value is a value increased by 10% of the reference frequency value, and the allowable frequency value is a value increased by 20% of the critical frequency. It may be a value increased by 20% of the critical frequency. That's okay.

[0067] In addition, for the wireless charging device according to the embodiment, in the first foreign substance detection, the control unit can determine whether the measured frequency value is less than or equal to the allowable frequency value. In addition, for the wireless charging device according to the embodiment, the control unit can determine whether the measured frequency value is less than or equal to the allowable frequency value.

[0068] In addition, for the wireless charging device according to the embodiment, if the measured frequency value is less than or equal to the allowable frequency value, the control unit can transmit an ACK for performing wireless charging. In addition, for the wireless charging device according to the embodiment, if the measured frequency value is less than or equal to the allowable frequency value, the control unit can transmit an ACK for performing wireless charging.

[0069] In addition, for the wireless charging device according to the embodiment, after transitioning to the correction stage, the control unit measures If the measured frequency value is less than or equal to the critical frequency value, a correction is performed and the measured frequency If the value exceeds the critical frequency value, no correction may be performed.

[0070] In the wireless charging device according to the embodiment, the FOD status packet further includes a reference frequency value. The sensing unit measures an equivalent series resistance value, and the control unit determines the value of the equivalent series resistance value based on the A critical equivalent series resistance is determined using the quasi-Q value and the reference frequency value, and the critical equivalent series resistance is The first foreign substance detection is performed by determining an allowable equivalent series resistance value using the measured equivalent series resistance value. The allowable equivalent series resistance can be based on the valence series resistance.

[0071] In the wireless charging device according to the embodiment, the critical equivalent series resistance is the permissible equivalent series resistance is a 10% increase in the critical equivalent series resistance may be increased by 20%.

[0072] In addition, in the wireless charging device according to the embodiment, the first foreign matter detection is performed by the control unit. It can be determined whether the measured equivalent series resistance is equal to or less than the allowable equivalent series resistance.

[0073] In a wireless charging device according to an embodiment, the control unit is If the equivalent series resistance is equal to or less than the permissible equivalent series resistance, an ACK for wireless charging can be transmitted. can.

[0074] In addition, in the wireless charging device according to the embodiment, after the transition to the correction stage, the control unit If the measured equivalent series resistance is less than or equal to the critical equivalent series resistance, a correction is performed. If the calculated equivalent series resistance exceeds the critical equivalent series resistance, no correction may be performed. .

[0075] Also, in order to solve the above technical problems, the wireless charging method according to the embodiment is wireless In a wireless charging method in a wireless power transmitter that wirelessly transmits power to a wireless power receiver, charging Sensing an object in the area, measuring an equivalent series resistance value and a peak frequency value, and a reference Receiving information including a Q value and a reference peak frequency value, a first critical equivalent series resistance value and Determining a critical peak frequency value, and using the measured equivalent series resistance value, the measured Peak frequency value, the first critical equivalent series resistance value, and the critical peak frequency value to detect different Substances, and the wireless power transmitter may determine that a foreign substance is present and stop power transmission if the measured equivalent series resistance value is Greater than or equal to the first critical equivalent series resistance value and the measured peak frequency value is greater than or equal to the critical peak Frequency value. .

[0076] Also, in the wireless charging method according to the embodiment, the step of determining the first critical equivalent series resistance value is Determining a reference equivalent series resistance value using the reference Q value and the reference peak frequency value, and Determining a value obtained by decreasing the reference equivalent series resistance value by a predetermined ratio as the first critical equivalent series resistance Value.

[0077] Also, in the wireless charging method according to the embodiment, the critical peak frequency value may be greater than the reference peak frequency value.

[0078] Also, in the wireless charging method according to the embodiment, if the measured peak frequency value is greater than or equal to the critical peak Frequency value and the measured equivalent series resistance value is less than or equal to the first critical equivalent series resistance value If so, information indicating that no foreign substance has been detected can be transmitted to the wireless power receiver. This is possible.

[0079] The wireless charging device according to the embodiment includes an inverter that converts DC power into AC power, a resonant capacitor, a transmission coil, a resonant circuit to which the AC power is applied, a communication unit that demodulates a modulated in-band signal from a wireless power receiver, a sensing unit that measures the voltage of the resonant circuit, and a control unit. The control unit senses an object in the charging area, determines a Q value and a peak frequency value based on the voltage measured by the sensing unit, receives information including a reference Q value and a reference peak frequency value through the communication unit, determines a first critical equivalent series resistance value and a critical peak frequency value, and is set to detect a foreign substance by using the measured equivalent series resistance value, the measured peak frequency value, the first critical equivalent series resistance value described above, and the critical peak frequency value. If the measured equivalent series resistance value is greater than or equal to the first critical equivalent series resistance value and the measured peak frequency value is greater than or equal to the critical peak frequency value, the wireless power transmitter can determine that a foreign substance is present and stop power transmission. and a transmission coil, a resonant circuit to which the AC power is applied, a communication unit that demodulates a modulated in-band signal from a wireless power receiver, a sensing unit that measures the voltage of the resonant circuit, and a control unit. The control unit senses an object in the charging area, determines a Q value and a peak frequency value based on the voltage measured by the sensing unit, receives information including a reference Q value and a reference peak frequency value through the communication unit, determines a first critical equivalent series resistance value and a critical peak frequency value, and is set to detect a foreign substance by using the measured equivalent series resistance value, the measured peak frequency value, the first critical equivalent series resistance value described above, and the critical peak frequency value. If the measured equivalent series resistance value is greater than or equal to the first critical equivalent series resistance value and the measured peak frequency value is greater than or equal to the critical peak frequency value, the wireless power transmitter can determine that a foreign substance is present and stop power transmission. and a transmission coil, a resonant circuit to which the AC power is applied, a communication unit that demodulates a modulated in-band signal from a wireless power receiver, a sensing unit that measures the voltage of the resonant circuit, and a control unit. The control unit senses an object in the charging area, determines a Q value and a peak frequency value based on the voltage measured by the sensing unit, receives information including a reference Q value and a reference peak frequency value through the communication unit, determines a first critical equivalent series resistance value and a critical peak frequency value, and is set to detect a foreign substance by using the measured equivalent series resistance value, the measured peak frequency value, the first critical equivalent series resistance value described above, and the critical peak frequency value. If the measured equivalent series resistance value is greater than or equal to the first critical equivalent series resistance value and the measured peak frequency value is greater than or equal to the critical peak frequency value, the wireless power transmitter can determine that a foreign substance is present and stop power transmission. and a control unit. The control unit senses an object in the charging area, determines a Q value and a peak frequency value based on the voltage measured by the sensing unit, receives information including a reference Q value and a reference peak frequency value through the communication unit, determines a first critical equivalent series resistance value and a critical peak frequency value, and is set to detect a foreign substance by using the measured equivalent series resistance value, the measured peak frequency value, the first critical equivalent series resistance value described above, and the critical peak frequency value. If the measured equivalent series resistance value is greater than or equal to the first critical equivalent series resistance value and the measured peak frequency value is greater than or equal to the critical peak frequency value, the wireless power transmitter can determine that a foreign substance is present and stop power transmission. and determines a Q value and a peak frequency value based on the voltage measured by the sensing unit, receives information including a reference Q value and a reference peak frequency value through the communication unit, determines a first critical equivalent series resistance value and a critical peak frequency value, and is set to detect a foreign substance by using the measured equivalent series resistance value, the measured peak frequency value, the first critical equivalent series resistance value described above, and the critical peak frequency value. If the measured equivalent series resistance value is greater than or equal to the first critical equivalent series resistance value and the measured peak frequency value is greater than or equal to the critical peak frequency value, the wireless power transmitter can determine that a foreign substance is present and stop power transmission. and receives information including a reference Q value and a reference peak frequency value through the communication unit, determines a first critical equivalent series resistance value and a critical peak frequency value, and is set to detect a foreign substance by using the measured equivalent series resistance value, the measured peak frequency value, the first critical equivalent series resistance value described above, and the critical peak frequency value. If the measured equivalent series resistance value is greater than or equal to the first critical equivalent series resistance value and the measured peak frequency value is greater than or equal to the critical peak frequency value, the wireless power transmitter can determine that a foreign substance is present and stop power transmission. and determines a first critical equivalent series resistance value and a critical peak frequency value, and is set to detect a foreign substance by using the measured equivalent series resistance value, the measured peak frequency value, the first critical equivalent series resistance value described above, and the critical peak frequency value. If the measured equivalent series resistance value is greater than or equal to the first critical equivalent series resistance value and the measured peak frequency value is greater than or equal to the critical peak frequency value, the wireless power transmitter can determine that a foreign substance is present and stop power transmission. and is set to detect a foreign substance by using the measured equivalent series resistance value, the measured peak frequency value, the first critical equivalent series resistance value described above, and the critical peak frequency value. If the measured equivalent series resistance value is greater than or equal to the first critical equivalent series resistance value and the measured peak frequency value is greater than or equal to the critical peak frequency value, the wireless power transmitter can determine that a foreign substance is present and stop power transmission. If the measured equivalent series resistance value is greater than or equal to the first critical equivalent series resistance value and the measured peak frequency value is greater than or equal to the critical peak frequency value, the wireless power transmitter can determine that a foreign substance is present and stop power transmission. If the measured equivalent series resistance value is greater than or equal to the first critical equivalent series resistance value and the measured peak frequency value is greater than or equal to the critical peak frequency value, the wireless power transmitter can determine that a foreign substance is present and stop power transmission.

[0080] Also, in the wireless charging device according to the embodiment, the first critical equivalent series resistance value may be determined based on the reference Q value and the reference peak frequency value. Also, in the wireless charging device according to the embodiment, the first critical equivalent series resistance value may be determined based on the reference Q value and the reference peak frequency value.

Advantages of the Invention

[0081] Describing the effects of the wireless charging method, the device, and the system therefor according to the present invention is as follows. It is as follows.

[0082] The present invention can provide a wireless charging method, a device, and a system therefor. ​

[0083] In addition, the present invention can accurately determine foreign substances.

[0084] In addition, the present invention can accurately determine foreign substances and prevent heat generation phenomena, reduction of charging efficiency, and waste of power consumption. from occurring.

[0085] In addition, the present invention can solve the problem that wireless charging is not performed because foreign substances are misrecognized as existing in the past.

[0086] In addition, the present invention can distinguish and determine an increase in the charging distance between a wireless power transmitter and a wireless power receiver and the presence of foreign substances, thereby solving the problem that wireless charging is not unnecessarily performed.

Brief Description of the Drawings

[0087] The drawings attached below are provided together with a detailed description to assist in understanding the present invention. However, the technical features of the present invention are not limited to specific drawings, and the features disclosed in each drawing can be combined with each other to form a new embodiment.

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Mode for Carrying Out the Invention

[0088] Hereinafter, with reference to the drawings, the devices and various methods to which the embodiments are applied will be described in more detail. is clarified. In the following description, the suffixes "module" and "section" for the components used are , simply given or mixed for the purpose of easily creating the specification, and by themselves, do not have a mutually distinguishable meaning or role.

[0089] Even if it is described that all the components constituting the embodiment are combined into one or combined and operate , it is not necessarily limited to such an embodiment. That is, within the scope of the purpose of the embodiment, all of its components may be selectively combined into one or more and operate . Also, all of its components may be implemented as one independent piece of hardware, but part or all of each component may be selectively combined to perform part or all of the functions combined by one or multiple pieces of hardware and may be embodied as a computer program having program modules. The code and code segments constituting the computer program can be easily deduced by those skilled in the technical field of the embodiment. Such a computer program is stored in a computer-readable medium (Computer Readable Media) and can be read and executed by a computer to embody the embodiment. As the storage medium of the computer program , magnetic recording media, optical recording media, carrier wave media, etc. can be included. In the description of the embodiment, when it is described that it is formed "above or below" and "in front or behind" of each component, "above or below" and "in front or behind" mean that two components are in direct contact with each other , or are formed with one or more other components arranged between the two components.

[0090] In the description of the embodiment, when it is described that it is formed "above or below" and "in front or behind" of each component, "above or below" and "in front or behind" mean that two components are in direct contact with each other , or are formed with one or more other components arranged between the two components. includes.

[0091] In addition, terms such as "include", "comprise", or "have" described above shall, unless there is a contrary description, mean that the constituent elements can be inherent, so they are not intended to exclude other constituent elements, but should be construed as being able to further include other constituent elements. All terms, including technical or scientific terms, shall, unless otherwise limited, have the same meaning as generally understood by those having ordinary knowledge in the technical field to which the embodiments belong. Commonly used terms, such as those defined in a dictionary, shall be construed as consistent with the meaning in the context of the relevant technology, and in the embodiments, shall not be construed in an ideal or overly formal sense unless clearly defined. Unless otherwise limited, they have the same meaning as generally understood by those having ordinary knowledge in the technical field to which the embodiments belong. Also, in the description of the constituent elements of the embodiments, terms such as first, second, A, B, (a), (b), etc. can be used. Such terms are only for distinguishing the constituent elements from other constituent elements, and do not limit the essence, order, or sequence of the constituent elements by such terms. When a constituent element is described as being "connected", "coupled", or "joined" to another constituent element, that constituent element can be directly connected or joined to the other constituent element, but it should be understood that other constituent elements can be further "connected", "coupled", or

[0092] "joined" between each constituent element. For the purpose of distinguishing the constituent element from other constituent elements, and do not limit the essence, order, or sequence of the constituent element by such terms. When a certain constituent element is described as being "connected", "coupled", or "joined" to another constituent element, that constituent element can be directly connected or joined to the other constituent element, but it should be understood that other constituent elements can be further "connected", "coupled", or "joined" between each constituent element. It should be understood that they can be "connected", "coupled", or "joined" between each constituent element.

[0093] And in the description of the embodiments, for related known technologies, if it is determined that there is a risk of unnecessarily obscuring the gist of the embodiments as obvious matters to those skilled in the art in this field, the detailed description thereof may be omitted. When it is determined that there is a risk of unnecessarily obscuring the gist of the embodiments as obvious matters to those skilled in the art in this field, the detailed description thereof may be omitted.

[0094] In the description of the embodiments, for the sake of convenience of description, the device that transmits wireless power in the wireless power charging system is referred to as wireless power transmitter, wireless power transmission device, wireless power transmitter, transmission end, transmitter device, transmission device, transmission side, wireless power transmission device, wireless power transmitter, wireless charging device, etc. are used interchangeably. Also, as the expression of the device that receives wireless power from the wireless power transmission device, for the sake of convenience of description, wireless power receiving device, wireless power receiver, wireless power receiving device, wireless power receiver receiver, receiving terminal, receiving side, receiving device, receiver terminal, etc. may be used interchangeably.

[0095] The wireless charging device according to the embodiments can be configured in a pad form, a docking station form, an AP (Access Point) form, a small base station form, a stand form, a ceiling-embedded form, a wall-mounted form, etc., and one transmitter can also transmit power to a plurality of wireless power receiving devices.

[0096] As an example, the wireless power transmitter can be used not only by being placed on a desk or a table as usual, but also developed and applied for automobiles and can be used inside a vehicle. The wireless power transmitter installed in the vehicle is provided in a stand form that can be easily and stably fixed and mounted.

[0097] The terminal according to the embodiments includes a mobile phone, a smart phone, a laptop computer, a digital broadcast terminal, a PDA (Personal Digital Assistant) ts, a PMP (Portable Multimedia Player), a navigation device, an MP3 player, an electric toothbrush, ​​​It can be used for small electronic devices such as electronic tags, lighting devices, remote controls, floats, etc., but is not limited to these. Any mobile device equipped with the wireless power receiving means according to the embodiment and capable of charging the battery (hereinafter referred to as "device") is acceptable. The terms "terminal" and "device" may be used interchangeably. The wireless power receiver according to another embodiment can also be mounted on vehicles, unmanned aerial vehicles, drones, etc.

[0098] The wireless power receiver according to the embodiment is provided with at least one wireless power transmission method and can receive wireless power from two or more wireless power transmitters simultaneously. Here, the wireless power transmission method can include at least one of the electromagnetic induction method, electromagnetic resonance method, and RF wireless power transmission method. Generally, the wireless power transmitter and the wireless power receiver constituting the wireless power system can exchange control signals or information through in-band communication or BLE (Bluetooth Low Energy) communication. Here, the in-band communication and BLE communication may be performed by a pulse width modulation (PWM) method, frequency modulation method, phase modulation method, amplitude modulation method, amplitude and phase modulation method, etc. As an example, the wireless power receiver can transmit various control signals and information to the wireless power transmitter by ON / OFF switching the current induced through the receiving coil in a predetermined pattern to generate a feedback signal. The information transmitted by the wireless power receiver can include various state information including information on the received power intensity. At this time, the wireless power transmitter can calculate the charging efficiency or power transmission efficiency based on the information on the received power intensity.

[0099] FIG. 1 is a block diagram for explaining a wireless power charging system according to an embodiment.

[0100] Referring to FIG. 1, the wireless power charging system mainly includes a wireless power transmitting end 10 that wirelessly transmits power, a wireless power receiving end 20 that receives the transmitted power, and an electronic device 30 to which the received power is supplied.

[0101] As an example, the wireless power transmitting end 10 and the wireless power receiving end 20 can perform In-band communication to exchange information using the same frequency band as the operating frequency used for wireless power transmission. As another example, the wireless power transmitting end 10 and the wireless power receiving end 20 can also perform Out-of-band communication to exchange information using a separate frequency band different from the operating frequency used for wireless power transmission.

[0102] As an example, the information exchanged between the wireless power transmitting end 10 and the wireless power receiving end 20 may include not only mutual status information but also control information. Here, the status information and control information exchanged between the transmitting and receiving ends will become clearer from the description of the embodiments to be described later.

[0103] The In-band communication and Out-of-band communication can provide two-way communication, but are not limited thereto. In another embodiment, one-way communication or half-duplex communication can also be provided.

[0104] As an example, the one-way communication may be that the wireless power receiving end 20 transmits information only to the wireless power transmitting end 10, but is not limited thereto. The wireless power transmitting end 10 may also transmit information to the wireless power receiving end 20. ​

[0105] The half-duplex communication method enables two-way communication between the wireless power receiving end 20 and the wireless power transmitting end 10 However, it has the characteristic that information transmission is possible by only one of the devices at a certain point in time.

[0106] The wireless power receiving end 20 according to the embodiment can also obtain various state information of the electronic device 30 As an example, the state information of the electronic device 30 can include current power consumption information, information for identifying the running application, CPU usage information, battery charging state information, battery output voltage / current information, etc., but is not limited thereto, and any information that can be obtained from the electronic device 30 and can be utilized for wireless power control is acceptable.

[0107] FIG. 2 is a state transition diagram for explaining the wireless power transmission procedure.

[0108] Referring to FIG. 2, according to the wireless power transmission procedure, the power transmission from the transmitter to the receiver is broadly divided into a selection phase 210, a ping phase 220, an identification and configuration phase 230, a negotiation phase 240, a calibration phase 250, a power transfer phase 260, and a renegotiation phase 270. The selection phase 210 is a phase that transitions when a specific error or a specific event is detected while starting or maintaining power transmission, for example, reference numerals S202, S204, S2

[0109] in the drawing, S206, etc. 06, etc. in the drawing. ​It can include 08, S210, and S212. Here, the specific error and specific event will become clearer from the following description. Also, at the selection stage 210, the transmitter can monitor whether there is an object on the interface surface. If the transmitter senses that an object is placed on the interface surface, it can transition to the ping stage 220. At the selection stage 210, the transmitter transmits a very short pulse Analog Ping signal and can sense whether there is an object in the active area on the interface surface based on the current change in the transmission coil or the primary coil.

[0110] If an object is sensed at the selection stage 210, the wireless power transmitter can measure the Q value (Quality factor) at one end and / or the other end of the transmission coil and / or resonant capacitor for wireless power transmission in a wireless power resonance circuit, for example.

[0111] The wireless power transmitter can measure the peak frequency of the wireless power resonance circuit (for example, the power transmission coil and / or resonant capacitor).

[0112] The Q value and / or the peak frequency are used to determine whether there is a foreign substance in the subsequent negotiation stage 240.

[0113] When the transmitter senses an object at the ping stage 220, it wakes up the receiver and transmits a Digital Ping to identify whether the sensed object is a wireless power receiver (S201). At the ping stage 220, the transmitter is the response signal to the digital ping ​​​​​​If, for example, the receiver cannot receive the signal strength packet, the process returns to the selection step 210 again. Also, in the ping step 220, if the transmitter receives a signal indicating that the power transmission from the receiver has been completed, i.e., a charging completion packet, it can move to the selection step 210 (S202).

[0114] After the ping step 220 is completed, the transmitter can move to the identification and configuration step 230 to identify the receiver and collect receiver configuration and status information (S203).

[0115] In the identification and configuration step 230, if the transmitter receives an unexpected packet, or if the desired packet is not received within a predefined time (time out), or if there is a packet transmission error, or if no power transfer contract is set, it can move to the selection step 210 (S204). cket), or if the desired packet is not received within a predefined time (time out), or if there is a packet transmission error, or if no power transfer contract is set, it can move to the selection step 210 (S204). cket transmission error), or if no power transfer contract is set (no power transfer contract), it can move to the selection step 210 (S204).

[0116] The transmitter can check whether it is necessary to enter the negotiation step 240 based on the value of the negotiation field in the configuration packet received in the identification and configuration step 230. t) of the negotiation field (Negotiation Field) value.

[0117] If the result of the check indicates that negotiation is necessary, the transmitter can enter the negotiation step 240 (S205). In the negotiation step 240, the transmitter can perform a predetermined FOD detection procedure.

[0118] On the other hand, if the result of the check indicates that negotiation is not necessary, the transmitter can directly enter the power transmission step 260 (S206). ​​​​​​​

[0119] In negotiation stage 340, the transmitter can receive a FOD (Foreign Object Detection) status packet containing a reference Q value. Or, it can receive a FOD status packet containing a reference peak frequency value. Or, it can receive a status packet containing both a reference Q value and a reference peak frequency value. At this time, the transmitter can determine a critical Q value for FO detection based on the reference Q value. The transmitter can determine a critical peak frequency value for FO detection based on the reference peak frequency value. The transmitter can utilize the determined critical Q value for FO detection and the currently measured Q value, for example, the Q value measured before the ping stage, to detect whether there is an FO in the charging area, and can control power transmission according to the FO detection result. As an example, when an FO is detected, power transmission is stopped, but it is not limited to this. The transmitter can utilize the determined critical peak frequency value for FO detection and the currently measured peak frequency value, for example, the peak frequency value measured before the ping stage, to detect whether there is an FO in the charging area, and can control power transmission according to the FO detection result. As an example, when an FO is detected, power transmission is stopped, but it is not limited to this. When an FO is detected, the transmitter can return to the selection stage 210 (S208). On the contrary, when no FO is detected, the transmitter goes through the correction stage 250 and then proceeds to the power transmission stage 260.

[0120]

[0121]

[0122] ​​​​​​​​​​​​​​It can also enter (S207 and S209). Specifically, when the FO is not detected, the transmitter receives the intensity of the power received at the receiving end in the correction stage 250, and can measure the power loss between the receiving end and the transmitting end by comparing it with the intensity of the power transmitted at the transmitting end. That is, the transmitter can predict the power loss based on the difference between the transmission power at the transmitting end and the received power at the receiving end in the correction stage 250. The transmitter according to an embodiment can also correct the power loss threshold for detecting FOD by reflecting the predicted power loss. That is, in the correction stage, since there is no FO, the power loss due to the coupling state of the receiver and the friendly metal component of the receiver is determined, and it can be determined that there is a foreign substance when additional power loss other than the pre-determined power loss occurs. When the FO is not detected, the transmitter receives the intensity of the power received at the receiving end in the correction stage 250, and measures the power loss between the receiving end and the transmitting end by comparing it with the intensity of the power transmitted at the transmitting end. It can be done. That is, in the correction stage 250, the transmitter can predict the power loss based on the difference between the transmission power at the transmitting end and the received power at the receiving end. The transmitter according to an embodiment can also correct the power loss threshold for detecting FOD by reflecting the predicted power loss. That is, in the correction stage, since there is no FO, the coupling state of the receiver and the power loss due to the friendly metal component of the receiver is determined, and it can be determined that there is a foreign substance when additional power loss other than the pre-determined power loss occurs.

[0123] In the power transmission stage 260, the transmitter may receive an unexpected packet, or a desired packet may not be received within a pre-defined time (time out), or a violation of a pre-set power transfer contract may occur (power transfer contract violation), or when charging is completed, it can move to the selection stage 210 (S210).

[0124] Also, in the power transmission stage 260, if the transmitter needs to reconfigure the power transfer contract due to a change in the transmitter state or the like, it can move to the renegotiation stage 270 (S211). At this time, if the renegotiation is completed normally, the transmitter can return to the power transmission stage 260 ( S213).

[0125] The above power transmission contract may be set based on the states and characteristic information of the transmitter and the receiver. For example, the transmitter state information may include information on the maximum transmissible power amount, information on the maximum number of receivers that can be accommodated, etc., and the receiver state information may include information on the required power, etc. If renegotiation does not complete normally, the transmitter may suspend power transmission to the receiver and may also transition to the selection stage 210 (S212).

[0126]

[0127] FIG. 3 is a block diagram for explaining the structure of a wireless power transmitter according to an embodiment.

[0128] Referring to FIG. 3, the wireless power transmitter 300 includes a power supply unit 360, a DC-DC converter 310, an inverter 320, a resonance circuit 330, a sensing unit 350, a communication unit 340, an alarm unit 370, and a control unit 380. The resonance circuit 330 includes a resonance capacitor 331 and an inductor (or transmission coil) 332, and the communication unit 340 includes at least one of a demodulation unit 341 and a modulation unit 342.

[0129]

[0130] The power supply unit 360 can have DC power applied from an external power supply terminal or a battery and transmit it to the DC-DC converter 310. Here, the battery is mounted inside the wireless power transmitter 300 and configured to be rechargeable, but this is only an example, and it may be connected to the power supply unit 360 of the wireless power transmitter 300 in the form of an auxiliary battery or an external battery via a predetermined cable.

[0131] The DC-DC converter 310 can convert the intensity of the DC power input from the power supply unit 360 according to the control of the control unit 380 into DC power of a specific intensity. As an example, the DC-DC converter 310 is configured as a variable voltage regulator capable of adjusting the intensity of the voltage, but it is not limited thereto.

[0132] The inverter 320 can convert the converted DC power into AC power.

[0133] The inverter 320 can convert the input DC power signal into an AC power signal and output it by means of a plurality of provided switch controls.

[0134] As an example, the inverter 320 is configured to include a full bridge circuit, but it is not limited thereto and may be configured to include a half bridge.

[0135] As another example, the inverter 320 may be configured to include both a half bridge circuit and a full bridge circuit. In this case, the control unit 380 can dynamically determine and control whether to operate the inverter 320 in the half bridge mode or the full bridge mode.

[0136] The wireless power transmitter according to an embodiment can adaptively control the bridge mode of the inverter 320 according to the intensity of the power required by the wireless power receiver.

[0137] Here, the bridge mode includes a half bridge mode and a full bridge mode. As an example, when the wireless power receiver requests 5W of low power, the control unit 380 The control unit 380 can control the inverter 320 to operate in the half-bridge mode.

[0138] On the contrary, when the wireless power receiver requires 15 W of power, the control unit 380 can control the inverter 320 to operate in the full-bridge mode. As another example, the wireless power transmitter can adaptively determine the bridge mode according to the sensed temperature, and drive the inverter 320 according to the determined bridge mode. - mode. As another example, the wireless power transmitter can adaptively determine the bridge mode according to the sensed temperature, and drive the inverter 320 according to the determined bridge mode. - mode. As another example, the wireless power transmitter can adaptively determine the bridge mode according to the sensed temperature, and drive the inverter 320 according to the determined bridge mode. - mode. As another example, the wireless power transmitter can adaptively determine the bridge mode according to the sensed temperature, and drive the inverter 320 according to the determined bridge mode.

[0139] As an example, during the transmission of wireless power in the half-bridge mode, when the temperature of the wireless power transmission device exceeds a predetermined reference value, the control unit 380 can deactivate the half-bridge mode and control the full-bridge mode to be activated. That is, the wireless power transmission device can increase the voltage through the full-bridge circuit to transmit the same intensity of power, and reduce the intensity of the current flowing through the resonant circuit 330, so as to control the internal temperature of the wireless power transmission device to be maintained below the predetermined reference value. As an example, during the transmission of wireless power in the half-bridge mode, when the temperature of the wireless power transmission device exceeds a predetermined reference value, the control unit 380 can deactivate the half-bridge mode and control the full-bridge mode to be activated. That is, the wireless power transmission device can increase the voltage through the full-bridge circuit to transmit the same intensity of power, and reduce the intensity of the current flowing through the resonant circuit 330, so as to control the internal temperature of the wireless power transmission device to be maintained below the predetermined reference value. As an example, during the transmission of wireless power in the half-bridge mode, when the temperature of the wireless power transmission device exceeds a predetermined reference value, the control unit 380 can deactivate the half-bridge mode and control the full-bridge mode to be activated. That is, the wireless power transmission device can increase the voltage through the full-bridge circuit to transmit the same intensity of power, and reduce the intensity of the current flowing through the resonant circuit 330, so as to control the internal temperature of the wireless power transmission device to be maintained below the predetermined reference value. As an example, during the transmission of wireless power in the half-bridge mode, when the temperature of the wireless power transmission device exceeds a predetermined reference value, the control unit 380 can deactivate the half-bridge mode and control the full-bridge mode to be activated. That is, the wireless power transmission device can increase the voltage through the full-bridge circuit to transmit the same intensity of power, and reduce the intensity of the current flowing through the resonant circuit 330, so as to control the internal temperature of the wireless power transmission device to be maintained below the predetermined reference value. As an example, during the transmission of wireless power in the half-bridge mode, when the temperature of the wireless power transmission device exceeds a predetermined reference value, the control unit 380 can deactivate the half-bridge mode and control the full-bridge mode to be activated. That is, the wireless power transmission device can increase the voltage through the full-bridge circuit to transmit the same intensity of power, and reduce the intensity of the current flowing through the resonant circuit 330, so as to control the internal temperature of the wireless power transmission device to be maintained below the predetermined reference value. As an example, during the transmission of wireless power in the half-bridge mode, when the temperature of the wireless power transmission device exceeds a predetermined reference value, the control unit 380 can deactivate the half-bridge mode and control the full-bridge mode to be activated. That is, the wireless power transmission device can increase the voltage through the full-bridge circuit to transmit the same intensity of power, and reduce the intensity of the current flowing through the resonant circuit 330, so as to control the internal temperature of the wireless power transmission device to be maintained below the predetermined reference value.

[0140] Generally, the amount of heat generated by the electronic components mounted on the electronic device is more sensitive to the intensity of the current than to the intensity of the voltage applied to the electronic components. Generally, the amount of heat generated by the electronic components mounted on the electronic device is more sensitive to the intensity of the current than to the intensity of the voltage applied to the electronic components.

[0141] In addition, the inverter 330 can not only convert DC power into AC power, but also change the intensity of the AC power. In addition, the inverter 330 can not only convert DC power into AC power, but also change the intensity of the AC power.

[0142] As an example, the inverter 320 adjusts the frequency of the reference alternating current signal used for AC power generation according to the control of the control unit 380, and outputs As an example, the inverter 320 adjusts the frequency of the reference alternating current signal used for AC power generation according to the control of the control unit 380, and outputs The intensity of the alternating current can also be adjusted. To this end, the inverter 320 includes a frequency oscillator that generates a reference alternating current signal having a specific frequency, but this is only one embodiment, and in another example, the frequency oscillator may be configured separately from the inverter 320 and mounted on one side of the wireless power transmitter 300. This is only one example, and in another example, the frequency oscillator may be configured separately from the inverter 320 and mounted on one side of the wireless power transmitter 300. This is only one example, and in another example, the frequency oscillator may be configured separately from the inverter 320 and mounted on one side of the wireless power transmitter 300. This is only one example, and in another example, the frequency oscillator may be configured separately from the inverter 320 and mounted on one side of the wireless power transmitter 300.

[0143] As another example, the wireless power transmitter 300 further includes a gate driver (not shown) for controlling the switches provided in the inverter 320. In this case, the gate driver can receive at least one pulse width modulation signal from the control unit 380 and control the switches of the inverter 320 according to the received pulse width modulation signal. The control unit 380 can control the duty cycle, that is, the duty rate and phase of the pulse width modulation signal to control the intensity of the power output by the inverter 320. The control unit 360 can adaptively control the duty cycle and phase of the pulse width modulation signal based on the feedback signal received from the wireless power receiving device. As another example, the wireless power transmitter 300 further includes a gate driver (not shown) for controlling the switches provided in the inverter 320. In this case, the gate driver can receive at least one pulse width modulation signal from the control unit 380 and control the switches of the inverter 320 according to the received pulse width modulation signal. The control unit 380 can control the duty cycle, that is, the duty rate and phase of the pulse width modulation signal to control the intensity of the power output by the inverter 320. The control unit 360 can adaptively control the duty cycle and phase of the pulse width modulation signal based on the feedback signal received from the wireless power receiving device. As another example, the wireless power transmitter 300 further includes a gate driver (not shown) for controlling the switches provided in the inverter 320. In this case, the gate driver can receive at least one pulse width modulation signal from the control unit 380 and control the switches of the inverter 320 according to the received pulse width modulation signal. The control unit 380 can control the duty cycle, that is, the duty rate and phase of the pulse width modulation signal to control the intensity of the power output by the inverter 320. The control unit 360 can adaptively control the duty cycle and phase of the pulse width modulation signal based on the feedback signal received from the wireless power receiving device. As another example, the wireless power transmitter 300 further includes a gate driver (not shown) for controlling the switches provided in the inverter 320. In this case, the gate driver can receive at least one pulse width modulation signal from the control unit 380 and control the switches of the inverter 320 according to the received pulse width modulation signal. The control unit 380 can control the duty cycle, that is, the duty rate and phase of the pulse width modulation signal to control the intensity of the power output by the inverter 320. The control unit 360 can adaptively control the duty cycle and phase of the pulse width modulation signal based on the feedback signal received from the wireless power receiving device. As another example, the wireless power transmitter 300 further includes a gate driver (not shown) for controlling the switches provided in the inverter 320. In this case, the gate driver can receive at least one pulse width modulation signal from the control unit 380 and control the switches of the inverter 320 according to the received pulse width modulation signal. The control unit 380 can control the duty cycle, that is, the duty rate and phase of the pulse width modulation signal to control the intensity of the power output by the inverter 320. The control unit 360 can adaptively control the duty cycle and phase of the pulse width modulation signal based on the feedback signal received from the wireless power receiving device. As another example, the wireless power transmitter 300 further includes a gate driver (not shown) for controlling the switches provided in the inverter 320. In this case, the gate driver can receive at least one pulse width modulation signal from the control unit 380 and control the switches of the inverter 320 according to the received pulse width modulation signal. The control unit 380 can control the duty cycle, that is, the duty rate and phase of the pulse width modulation signal to control the intensity of the power output by the inverter 320. The control unit 360 can adaptively control the duty cycle and phase of the pulse width modulation signal based on the feedback signal received from the wireless power receiving device. As another example, the wireless power transmitter 300 further includes a gate driver (not shown) for controlling the switches provided in the inverter 320. In this case, the gate driver can receive at least one pulse width modulation signal from the control unit 380 and control the switches of the inverter 320 according to the received pulse width modulation signal. The control unit 380 can control the duty cycle, that is, the duty rate and phase of the pulse width modulation signal to control the intensity of the power output by the inverter 320. The control unit 360 can adaptively control the duty cycle and phase of the pulse width modulation signal based on the feedback signal received from the wireless power receiving device. As another example, the wireless power transmitter 300 further includes a gate driver (not shown) for controlling the switches provided in the inverter 320. In this case, the gate driver can receive at least one pulse width modulation signal from the control unit 380 and control the switches of the inverter 320 according to the received pulse width modulation signal. The control unit 380 can control the duty cycle, that is, the duty rate and phase of the pulse width modulation signal to control the intensity of the power output by the inverter 320. The control unit 360 can adaptively control the duty cycle and phase of the pulse width modulation signal based on the feedback signal received from the wireless power receiving device. As another example, the wireless power transmitter 300 further includes a gate driver (not shown) for controlling the switches provided in the inverter 320. In this case, the gate driver can receive at least one pulse width modulation signal from the control unit 380 and control the switches of the inverter 320 according to the received pulse width modulation signal. The control unit 380 can control the duty cycle, that is, the duty rate and phase of the pulse width modulation signal to control the intensity of the power output by the inverter 320. The control unit 360 can adaptively control the duty cycle and phase of the pulse width modulation signal based on the feedback signal received from the wireless power receiving device.

[0144] The sensing unit 350 can measure the voltage / current of the DC-converted power and provide it to the control unit 380. Also, the sensing unit 350 can measure the internal temperature of the wireless power transmitter 300 or the inside of the charging interface (surface) to determine whether overheating has occurred and provide the measurement result to the control unit 380. As an example, the control unit 380 can be based on the voltage / current value or internal temperature value measured by the sensing unit 350. The sensing unit 350 can measure the voltage / current of the DC-converted power and provide it to the control unit 380. Also, the sensing unit 350 can measure the internal temperature of the wireless power transmitter 300 or the inside of the charging interface (surface) to determine whether overheating has occurred and provide the measurement result to the control unit 380. As an example, the control unit 380 can be based on the voltage / current value or internal temperature value measured by the sensing unit 350. The sensing unit 350 can measure the voltage / current of the DC-converted power and provide it to the control unit 380. Also, the sensing unit 350 can measure the internal temperature of the wireless power transmitter 300 or the inside of the charging interface (surface) to determine whether overheating has occurred and provide the measurement result to the control unit 380. As an example, the control unit 380 can be based on the voltage / current value or internal temperature value measured by the sensing unit 350. The sensing unit 350 can measure the voltage / current of the DC-converted power and provide it to the control unit 380. Also, the sensing unit 350 can measure the internal temperature of the wireless power transmitter 300 or the inside of the charging interface (surface) to determine whether overheating has occurred and provide the measurement result to the control unit 380. As an example, the control unit 380 can be based on the voltage / current value or internal temperature value measured by the sensing unit 350. The sensing unit 350 can measure the voltage / current of the DC-converted power and provide it to the control unit 380. Also, the sensing unit 350 can measure the internal temperature of the wireless power transmitter 300 or the inside of the charging interface (surface) to determine whether overheating has occurred and provide the measurement result to the control unit 380. As an example, the control unit 380 can be based on the voltage / current value or internal temperature value measured by the sensing unit 350. It is possible to adaptively cut off the power supply from the power supply unit 380. For this purpose, a predetermined power cutoff circuit for cutting off the power supply supplied from the power supply unit 360 may be further provided on one side of the DC-DC converter 310. On one side of the DC-DC converter 310, a predetermined power cutoff circuit for cutting off the power supply supplied from the power supply unit 360 may be further provided. A power cutoff circuit may be further provided.

[0145] In addition, the sensing unit 350 can include various sensing elements for sensing Q value, frequency value, equivalent series resistance value, etc. The sensing unit 350 can provide the sensed Q value, frequency value, equivalent series resistance value, etc. to the control unit 380. The sensing method of the sensing unit 350 will be described with reference to FIGS. 6 to 18 below. The sensing unit 350 can include various sensing elements for sensing the Q value, frequency value, equivalent series resistance value, etc. The sensing unit 350 can provide the sensed Q value, frequency value, equivalent series resistance value, etc. to the control unit 380. The sensing unit 350 can provide the sensed Q value, frequency value, equivalent series resistance value, etc. to the control unit 380. The sensing method of the sensing unit 350 will be described with reference to FIGS. 6 to 18 below. The sensing method of the sensing unit 350 will be described with reference to FIGS. 6 to 18 below.

[0146] The control unit 380 can detect foreign substances by using the FOD state information including one or more values of the sensed Q value, frequency value, equivalent series resistance value, etc. and the received reference Q value and reference frequency value. The foreign substance detection method of the control unit 380 will be described with reference to FIGS. 6 to 18 below. The control unit 380 can detect foreign substances by using the FOD state information including one or more values of the sensed Q value, frequency value, equivalent series resistance value, etc. and the received reference Q value and reference frequency value. The foreign substance detection method of the control unit 380 will be described with reference to FIGS. 6 to 18 below. The foreign substance detection method of the control unit 380 will be described with reference to FIGS. 6 to 18 below.

[0147] The modulation unit 342 can modulate the control signal generated by the control unit 380 and transmit it to the resonance coil 330. Here, the modulation method for modulating the control signal can include, but is not limited to, the FSK (Frequency Shift Keying) modulation method, the Manchester Coding modulation method, the PSK (Phase Shift Keying) modulation method, the Pulse Width Modulation method, the Differential bi-phase modulation method, etc. Here, the modulation method for modulating the control signal can include, but is not limited to, the FSK (Frequency Shift Keying) modulation method, the Manchester Coding modulation method, the PSK (Phase Shift Keying) modulation method, the Pulse Width Modulation method, the Differential bi-phase modulation method, etc. The modulation method for modulating the control signal can include, but is not limited to, the FSK (Frequency Shift Keying) modulation method, the Manchester Coding modulation method, the PSK (Phase Shift Keying) modulation method, the Pulse Width Modulation method, the Differential bi-phase modulation method, etc. The modulation method for modulating the control signal can include, but is not limited to, the FSK (Frequency Shift Keying) modulation method, the Manchester Coding modulation method, the PSK (Phase Shift Keying) modulation method, the Pulse Width Modulation method, the Differential bi-phase modulation method, etc. The modulation method for modulating the control signal can include, but is not limited to, the FSK (Frequency Shift Keying) modulation method, the Manchester Coding modulation method, the PSK (Phase Shift Keying) modulation method, the Pulse Width Modulation method, the Differential bi-phase modulation method, etc. The modulation method for modulating the control signal can include, but is not limited to, the FSK (Frequency Shift Keying) modulation method, the Manchester Coding modulation method, the PSK (Phase Shift Keying) modulation method, the Pulse Width Modulation method, the Differential bi-phase modulation method, etc.

[0148] When the demodulation unit 341 senses the signal received through the transmission coil, the sensed signal can be demodulated and transmitted to the control unit 380. As an example, the demodulated signal includes 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 / overheat indicator, etc., but is not limited thereto, and may include various status information for identifying the state of the wireless power receiver. As another example, the demodulated signal may include FOD status information including one or more values of a reference Q value and a reference frequency value.

[0149] As an example, the wireless power transmitter 300 can obtain the signal strength indicator through in-band communication that uses the same frequency used for wireless power transmission to communicate with the wireless power receiver.

[0150] In the above description of FIG. 3, it is described by taking as an example that the wireless power transmitter 300 and the wireless power receiver perform in-band communication, but this is only one embodiment, and short-range bidirectional communication can be performed through a frequency band different from the frequency band used for wireless power signal transmission. As an example, the short-range bidirectional communication may be any one of low-power Bluetooth communication, RFID communication, UWB communication, and ZigBee communication.

[0151] FIG. 4 is a block diagram for explaining the structure of a wireless power receiver interlocked with the wireless power transmitter of FIG. 3.

[0152] Referring to FIG. 4, the wireless power receiver 400 includes a reception coil 410, a rectifier 420, a DC ​​​​​​​ / DC / DC Converter 430, load 440, sensing unit 450, communication unit 460, and main control unit 470. Here, the communication unit 460 includes at least one of a demodulation unit 46 1 and a modulation unit 462.

[0153] The wireless power receiver 400 illustrated in the example of FIG. 4 above is illustrated as being capable of exchanging information with a wireless power transmitter through in-band communication, but this is only one example, and another The communication unit 460 according to another embodiment can also provide short-range two-way communication through a frequency band different from the frequency band used for wireless power signal transmission.

[0154] The AC power received through the receiving coil 410 can be transmitted to the rectifier 420. The rectifier 420 can convert the AC power into DC power and transmit it to the DC / DC converter 430. The DC / DC converter 430 can convert the intensity of the DC power output by the rectifier into a specific intensity required by the load 440 and transmit it to the load 440. Also, the receiving coil 410 includes a plurality of receiving coils (not shown), i.e., first to nth receiving coils. The frequencies of the AC power transmitted to each receiving coil (not shown) according to one embodiment may be different from each other. Another embodiment uses a predetermined frequency controller having a function of adjusting the LC resonance characteristics differently for each receiving coil so that the resonance frequencies of the respective receiving coils can be set differently.

[0155] The sensing unit 450 can measure the intensity of the DC power output by the rectifier 420 and provide it to the main control unit 470. As an example, the sensing unit 450 is a wireless power receiver​​​​ Measure the intensity of the current applied to the receiving coil 410, and transmit the measurement result to the main control unit 4 70. As another example, the sensing unit 450 can measure the internal temperature of the wireless power receiver 4 00 and provide the measured temperature value to the main control unit 470. This is also possible.

[0156] As an example, the main control unit 470 can determine whether an overvoltage has occurred by comparing the intensity of the DC power output by the measured rectifier with a predetermined reference value. As a result of the determination, if an overvoltage has occurred, a predetermined packet notifying the occurrence of the overvoltage can be generated and transmitted to the modulation unit 462. Here, the signal modulated by the modulation unit 462 is transmitted to the wireless power transmitter through the receiving coil 410 or a separate coil (not shown). In addition, when the intensity of the DC power output by the rectifier is equal to or greater than a predetermined reference value, the main control unit 470 can determine that a sensing signal has been received, and when the sensing signal is received, control is performed so that the signal strength indicator corresponding to the sensing signal is transmitted to the wireless power transmitter through the modulation unit 462. This is possible. As another example, the demodulation unit 461 can demodulate the AC power signal or the rectifier 420 output DC power signal between the receiving coil 410 and the rectifier 420 to identify whether a sensing signal has been received, and provide the identification result to the main control unit 470. At this time, the main control unit 470 can control so that the signal strength indicator corresponding to the sensing signal is transmitted through the modulation unit 462. In addition, the main control unit 470 can transmit an FOD status packet including one or more of a pre-stored reference Q value and reference frequency value to the wireless power transmitter through the modulation unit 462. This is possible. This is possible. As another example, the demodulation unit 461 can demodulate the AC power signal or the rectifier 420 output DC power signal between the receiving coil 410 and the rectifier 420 to identify whether a sensing signal has been received, and provide the identification result to the main control unit 470. At this time, the main control unit 470 can control so that the signal strength indicator corresponding to the sensing signal is transmitted through the modulation unit 462. This is possible. 470 can control so that the signal strength indicator corresponding to the sensing signal is transmitted through the modulation unit 462. This is possible.

[0157] In addition, the main control unit 470 can transmit an FOD status packet including one or more of a pre-stored reference Q value and reference frequency value to the wireless power transmitter through the modulation unit 462. This is possible. It can be controlled to be sendable.

[0158] FIG. 5 is a drawing for explaining a wireless charging method in a wireless charging system according to an embodiment. It is.

[0159] Referring to FIG. 5, the wireless power transmitter 610 can transmit an an alog ping to the wireless power receiver 620 in the selection stage (S601).

[0160] The wireless power transmitter 610 can measure the Q value before the ping stage (S602). As an example, the wireless power transmitter 610 can measure the Q value in the selection stage (S60 2).

[0161] Also, the wireless power transmitter 610 can measure the peak frequency value before the ping stage. It is possible (S603). As an example, the wireless power transmitter 610 measures the peak frequency value in the selection stage. It can be determined (S602). As another example, the wireless power transmitter 610 can measure the peak frequency of the transmission coil in the selection stage to determine the inductance value. More specifically, referring to Equation 1, the frequency value f can be determined using the fixed capacitance value C and the measured inductance value. It can be determined using the measured inductance value.

[0162] (Equation 1) TIFF0007705975000001.tif2545 When an object is detected, the wireless power transmitter 610 can transition from the selection stage to the ping stage. The wireless power transmitter 610 can activate the wireless power receiver 620 and transmit a digital ping to identify whether the receiver is a wireless power receiver 620 (S604). The wireless power receiver 620 responds to the digital ping with a signal strength packet. (S604). The wireless power receiver 620 responds to the digital ping with a signal strength packet. It can transmit the packet (S605).

[0163] When the ping stage is completed, in the identification and configuration stages, the wireless power receiver 620 can transmit an identification packet for notifying identification information and a configuration packet for notifying configuration information (S606~S607). If the negotiation field value of the configuration packet between the wireless power transmitter 610 and the wireless power receiver 620 is a value instructing to execute the negotiation stage, it can transition to the negotiation stage (S606~S607). If the negotiation field value of the configuration packet between the wireless power transmitter 610 and the wireless power receiver 620 is a value instructing to execute the negotiation stage, it can transition to the negotiation stage (S606~S607). If the negotiation field value of the configuration packet between the wireless power transmitter 610 and the wireless power receiver 620 is a value instructing to execute the negotiation stage, it can transition to the negotiation stage (S606~S607). If the negotiation field value of the configuration packet between the wireless power transmitter 610 and the wireless power receiver 620 is a value instructing to execute the negotiation stage, it can transition to the negotiation stage

[0164] In the negotiation stage, the wireless power receiver 620 can transmit an FOD status packet to detect FO (S606). The FOD status packet can include one or more of the reference Q value and the reference frequency value (S606). The FOD status packet can include one or more of the reference Q value and the reference frequency value (S606). The FOD status packet can include one or more of the reference Q value and the reference frequency value

[0165] The wireless power transmitter 610 can perform first foreign object detection (S609). The first foreign object detection can detect a foreign object by using the measured Q value, the measured frequency value, and the information of the received FOD status packet. The first foreign object detection refers to the description of the wireless charging method in FIGS. 7 to 12 (S609). The first foreign object detection can detect a foreign object by using the measured Q value, the measured frequency value, and the information of the received FOD status packet. The first foreign object detection refers to the description of the wireless charging method in FIGS. 7 to 12 (S609). The first foreign object detection can detect a foreign object by using the measured Q value, the measured frequency value, and the information of the received FOD status packet. The first foreign object detection refers to the description of the wireless charging method in FIGS. 7 to 12 (S609). The first foreign object detection can detect a foreign object by using the measured Q value, the measured frequency value, and the information of the received FOD status packet. The first foreign object detection refers to the description of the wireless charging method in FIGS. 7 to 12

[0166] When the wireless power transmitter 610 decides to perform wireless charging after the first foreign object detection, it can transmit an ACK to the wireless power receiver 620 as a response to the FOD status packet (S610). On the contrary, when the wireless power transmitter 610 decides to stop wireless charging after the first foreign object detection, it can transmit a NAK to the wireless power receiver 620 as a response to the FOD status packet (S610). On the contrary, when the wireless power transmitter 610 decides to stop wireless charging after the first foreign object detection, it can transmit a NAK to the wireless power receiver 620 as a response to the FOD status packet (S610). On the contrary, when the wireless power transmitter 610 decides to stop wireless charging after the first foreign object detection, it can transmit a NAK to the wireless power receiver 620 as a response to the FOD status packet (S610). On the contrary, when the wireless power transmitter 610 decides to stop wireless charging after the first foreign object detection, it can transmit a NAK to the wireless power receiver 620 as a response to the FOD status packet

[0167] The wireless power receiver 620 can transmit a general request packet requesting a power transmitter capability packet for a power transmission contract (S611). The wireless power transmitter 62 0 can transmit a power transmitter capability packet as a response to the general request packet ( S612). In this case, the guaranteed power of the power transmitter capability packet may be the first guaranteed power value. The potential power value may be the maximum transmission power value that the wireless power transmitter can send regardless of power limitations due to peripheral requirements or the like. As an example, the first guaranteed power value may be a value close to the potential power value that is not subject to power limitations due to the number of wireless power transmitters or the number of wireless power receivers based on the power supply provided from the power source unit of the wireless power transmitter. As another example, the first

[0168] guaranteed power value may be the maximum transmission power value that the wireless power transmitter can send under conditions (environmental conditions) such as power limitations due to the number of wireless power transmitters or the number of wireless power receivers. Environmental conditions may mean the temperature of the transmitter, the available amount of the power source of the transmitter, the presence of foreign substances, or the influence of friendly media, etc. The wireless power receiver 620 can transmit a special request packet for proposing the guaranteed power value of the power transmission contract based on the first guaranteed power value of the power transmitter capability packet (S613). It should be noted that the first guaranteed power of the power transmitter capability packet and the guaranteed power of the power transmission contract are distinct. For example, the wireless power receiver 620 can request the guaranteed power value of the power transmission contract to be the same as or smaller than the first guaranteed power value of the power transmitter capability packet. For the sake of convenience of explanation, the wireless power is based on the power supply provided from the power source unit of the wireless power transmitter, and is not subject to power limitations such as those caused by the number of wireless power transmitters or the number of wireless power receivers. As another example, the first guaranteed power value may be the maximum transmission power value that the wireless power transmitter can send under conditions (environmental conditions) such as power limitations due to the number of wireless power transmitters or the number of wireless power receivers. Environmental conditions may mean the temperature of the transmitter, the available amount of the power source of the transmitter, the presence of foreign substances, or the influence of friendly media, etc. The wireless power receiver 620 can transmit a special request packet for proposing the guaranteed power value of the power transmission contract based on the first guaranteed power value of the power transmitter capability packet (S613). It should be noted that the first guaranteed power of the power transmitter capability packet and the guaranteed power of the power transmission contract are distinct. For example, the wireless power receiver 620 can request the guaranteed power value of the power transmission contract to be the same as or smaller than the first guaranteed power value of the power transmitter capability packet. For the sake of convenience of explanation, the wireless power is based on the power supply provided from the power source unit of the wireless power transmitter, and is not subject to power limitations such as those caused by the number of wireless power transmitters or the number of wireless power receivers. As another example, the first guaranteed power value may be the maximum transmission power value that the wireless power transmitter can send under conditions (environmental conditions) such as power limitations due to the number of wireless power transmitters or the number of wireless power receivers. Environmental conditions may mean the temperature of the transmitter, the available amount of the power source of the transmitter, the presence of foreign substances, or the influence of friendly media, etc. The wireless power receiver 620 can transmit a special request packet for proposing the guaranteed power value of the power transmission contract based on the first guaranteed power value of the power transmitter capability packet (S613). It should be noted that the first guaranteed power of the power transmitter capability packet and the guaranteed power of the power transmission contract are distinct. For example, the wireless power receiver 620 can request the guaranteed power value of the power transmission contract to be the same as or smaller than the first guaranteed power value of the power transmitter capability packet. For the sake of convenience of explanation, the wireless power receiver 620 can transmit a special request packet for proposing the guaranteed power value of the power transmission contract based on the first guaranteed power value of the power transmitter capability packet (S613). It should be noted that the first guaranteed power of the power transmitter capability packet and the guaranteed power of the power transmission contract are distinct. For example, the wireless power receiver 620 can request the guaranteed power value of the power transmission contract to be the same as or smaller than the first guaranteed power value of the power transmitter capability packet. For the sake of convenience of explanation, the wireless power receiver 620 can transmit a special request packet for proposing the guaranteed power value of the power transmission contract based on the first guaranteed power value of the power transmitter capability packet (S613). It should be noted that the first guaranteed power of the power transmitter capability packet and the guaranteed power of the power transmission contract are distinct. For example, the wireless power receiver 620 can request the guaranteed power value of the power transmission contract to be the same as or smaller than the first guaranteed power value of the power transmitter capability packet. For the sake of convenience of explanation, the wireless power receiver 620 can transmit a special request packet for proposing the guaranteed power value of the power transmission contract based on the first guaranteed power value of the power transmitter capability packet (S613). It should be noted that the first guaranteed power of the power transmitter capability packet and the guaranteed power of the power transmission contract are distinct. For example, the wireless power receiver 620 can request the guaranteed power value of the power transmission contract to be the same as or smaller than the first guaranteed power value of the power transmitter capability packet. For the sake of convenience of explanation, the wireless power receiver 620 can request the guaranteed power value of the power transmission contract to be the same as or smaller than the first guaranteed power value of the power transmitter capability packet. For the sake of convenience of explanation, the wireless power receiver 620 can request the guaranteed power value of the power transmission contract to be the same as or smaller than the first guaranteed power value of the power transmitter capability packet. For the sake of convenience of explanation, the wireless power The power receiver 620 requests at the guaranteed power value of the power transmission contract, which is the same value as the first guaranteed power value of the power transmitter capability packet. The wireless power transmitter 610 can transmit an ACK packet as a response to a special request packet for requesting the guaranteed power value of the power transmission contract (S614). That is, the wireless power transmitter 610 accepts the guaranteed power value of the power transmission contract proposed by the wireless power receiver. That is, the power transmission contract can be completed at the first guaranteed power value. After that, when the power transmission contract is completed, the wireless power receiver 620 can transmit a special request packet for ending the negotiation stage (S615). The wireless power transmitter 610 can transmit an ACK packet as a response to the special request packet for ending the negotiation stage (S616). That is, the wireless power transmitter 610 can transmit an ACK packet as an acceptance for ending the negotiation stage. In the correction stage, the wireless power receiver 620 can transmit a received power packet to the wireless power transmitter 610 (S617). In this case, the received power packet may be a 24-bit received power packet. The wireless power transmitter 610 can transmit an ACK packet as a response to the received power packet for performing wireless charging (S618). The wireless power transmitter 610 can determine whether to execute correction (S619). The determination of whether to execute correction is the case of entering the correction execution stage in FIGS. 6 to 13b. As an example, when it is determined to execute correction, the correction execution is the received power value of the wireless power receiver 610 of the received power packet received by the wireless power transmitter 610 at S617 and the measured transmission power value. (S614). That is, the wireless power transmitter 610 accepts the guaranteed power value of the power transmission contract proposed by the wireless power receiver. That is, the power transmission contract can be completed at the first guaranteed power value. After that, when the power transmission contract is completed, the wireless power receiver 620 can transmit a special request packet for ending the negotiation stage (S615). The wireless power transmitter 610 can transmit an ACK packet as a response to the special request packet for ending the negotiation stage (S616). That is, the wireless power transmitter 610 can transmit an ACK packet as an acceptance for ending the negotiation stage. That is, the power transmission contract can be completed at the first guaranteed power value. After that, when the power transmission contract is completed, the wireless power receiver 620 can transmit a special request packet for ending the negotiation stage (S615). The wireless power transmitter 610 can transmit an ACK packet as a response to the special request packet for ending the negotiation stage (S616). That is, the wireless power transmitter 610 can transmit an ACK packet as an acceptance for ending the negotiation stage. After that, when the power transmission contract is completed, the wireless power receiver 620 can transmit a special request packet for ending the negotiation stage (S615). The wireless power transmitter 610 can transmit an ACK packet as a response to the special request packet for ending the negotiation stage (S616). That is, the wireless power transmitter 610 can transmit an ACK packet as an acceptance for ending the negotiation stage. The wireless power transmitter 610 can transmit an ACK packet as a response to the special request packet for ending the negotiation stage (S616). That is, the wireless power transmitter 610 can transmit an ACK packet as an acceptance for ending the negotiation stage. The wireless power transmitter 610 can transmit an ACK packet as a response to the special request packet for ending the negotiation stage (S616). That is, the wireless power transmitter 610 can transmit an ACK packet as an acceptance for ending the negotiation stage. That is, the wireless power transmitter 610 can transmit an ACK packet as an acceptance for ending the negotiation stage. That is, the wireless power transmitter 610 can transmit an ACK packet as an acceptance for ending the negotiation stage.

[0169] In the correction stage, the wireless power receiver 620 can transmit a received power packet to the wireless power transmitter 610 (S617). In this case, the received power packet may be a 24-bit received power packet. The wireless power transmitter 610 can transmit an ACK packet as a response to the received power packet for performing wireless charging (S618). In this case, the received power packet may be a 24-bit received power packet. The wireless power transmitter 610 can transmit an ACK packet as a response to the received power packet for performing wireless charging (S618). The wireless power transmitter 610 can transmit an ACK packet as a response to the received power packet for performing wireless charging (S618). The wireless power transmitter 610 can transmit an ACK packet as a response to the received power packet for performing wireless charging (S618).

[0170] The wireless power transmitter 610 can determine whether to execute correction (S619). The determination of whether to execute correction is the case of entering the correction execution stage in FIGS. 6 to 13b. As an example, when it is determined to execute correction, the correction execution is the received power value of the wireless power receiver 610 of the received power packet received by the wireless power transmitter 610 at S617 and the measured transmission power value. As an example, when it is determined to execute correction, the correction execution is the received power value of the wireless power receiver 610 of the received power packet received by the wireless power transmitter 610 at S617 and the measured transmission power value. It is possible to predict power loss by using it. Also, the correction execution is used for the second foreign object detection (S623) performed at the power transmission stage by the wireless power transmitter 610 to correct the power loss threshold value that is used. Also, the correction execution can increase the intensity of the transmitted power by using the predicted power loss value by the wireless power transmitter 61 0. If there is a foreign object (when present), the wireless power transmitter 610 does not have to execute the above correction. 0. After the correction stage is completed, the power transmission stage can be performed with the first guaranteed power. The wireless power receiver 620 can transmit one or more control error packets (S620) to control the current of the transmission coil of the wireless power transmitter 610. The wireless power transmitter 610 can control the current of the transmission coil based on the control error packet transmitted from the wireless power receiver 620 and adjust the transmitted power. The wireless power receiver 620 can transmit received power packets periodically or arbitrarily (S621). The wireless power transmitter 610 can perform the second foreign object detection (S622). As an example, the wireless power transmitter 610 uses the power value, which is the number of received power packets, and the measured transmitted power value to judge the power loss and detect whether there is a foreign object according to the power loss value. That is, when the power loss value exceeds a predetermined critical power loss value, it can be judged that there is a foreign object. In this case, the wireless power transmitter 610 sends a NAK packet as a response to the received power packet to the wireless power receiver 620 in order to stop charging.

[0171] The wireless power transmitter 610 can perform the second foreign object detection (S622). As an example, the wireless power transmitter 610 uses the power value, which is the number of received power packets, and the measured transmitted power value to judge the power loss and detect whether there is a foreign object according to the power loss value. That is, when the power loss value exceeds a predetermined critical power loss value, it can be judged that there is a foreign object. In this case, the wireless power transmitter 610 sends a NAK packet as a response to the received power packet to the wireless power receiver 620 in order to stop charging. The wireless power transmitter 610 can perform the second foreign object detection (S622). As an example, the wireless power transmitter 610 uses the power value, which is the number of received power packets, and the measured transmitted power value to judge the power loss and detect whether there is a foreign object according to the power loss value. That is, when the power loss value exceeds a predetermined critical power loss value, it can be judged that there is a foreign object. In this case, the wireless power transmitter 610 sends a NAK packet as a response to the received power packet to the wireless power receiver 620 in order to stop charging. The wireless power transmitter 610 can perform the second foreign object detection (S622). As an example, the wireless power transmitter 610 uses the power value, which is the number of received power packets, and the measured transmitted power value to judge the power loss and detect whether there is a foreign object according to the power loss value. That is, when the power loss value exceeds a predetermined critical power loss value, it can be judged that there is a foreign object. In this case, the wireless power transmitter 610 sends a NAK packet as a response to the received power packet to the wireless power receiver 620 in order to stop charging. The wireless power transmitter 610 can perform the second foreign object detection (S622). As an example, the wireless power transmitter 610 uses the power value, which is the number of received power packets, and the measured transmitted power value to judge the power loss and detect whether there is a foreign object according to the power loss value. That is, when the power loss value exceeds a predetermined critical power loss value, it can be judged that there is a foreign object. In this case, the wireless power transmitter 610 sends a NAK packet as a response to the received power packet to the wireless power receiver 620 in order to stop charging. The wireless power transmitter 610 can perform the second foreign object detection (S622). As an example, the wireless power transmitter 610 uses the power value, which is the number of received power packets, and the measured transmitted power value to judge the power loss and detect whether there is a foreign object according to the power loss value. That is, when the power loss value exceeds a predetermined critical power loss value, it can be judged that there is a foreign object. In this case, the wireless power transmitter 610 sends a NAK packet as a response to the received power packet to the wireless power receiver 620 in order to stop charging. The wireless power transmitter 610 can perform the second foreign object detection (S622). As an example, the wireless power transmitter 610 uses the power value, which is the number of received power packets, and the measured transmitted power value to judge the power loss and detect whether there is a foreign object according to the power loss value. That is, when the power loss value exceeds a predetermined critical power loss value, it can be judged that there is a foreign object. In this case, the wireless power transmitter 610 sends a NAK packet as a response to the received power packet to the wireless power receiver 620 in order to stop charging.

[0172] The wireless power transmitter 610 can perform the second foreign object detection (S622). As an example, the wireless power transmitter 610 uses the power value, which is the number of received power packets, and the measured transmitted power value to judge the power loss and detect whether there is a foreign object according to the power loss value. That is, when the power loss value exceeds a predetermined critical power loss value, it can be judged that there is a foreign object. In this case, the wireless power transmitter 610 sends a NAK packet as a response to the received power packet to the wireless power receiver 620 in order to stop charging. The wireless power transmitter 610 can perform the second foreign object detection (S622). As an example, the wireless power transmitter 610 uses the power value, which is the number of received power packets, and the measured transmitted power value to judge the power loss and detect whether there is a foreign object according to the power loss value. That is, when the power loss value exceeds a predetermined critical power loss value, it can be judged that there is a foreign object. In this case, the wireless power transmitter 610 sends a NAK packet as a response to the received power packet to the wireless power receiver 620 in order to stop charging. The wireless power transmitter 610 can perform the second foreign object detection (S622). As an example, the wireless power transmitter 610 uses the power value, which is the number of received power packets, and the measured transmitted power value to judge the power loss and detect whether there is a foreign object according to the power loss value. That is, when the power loss value exceeds a predetermined critical power loss value, it can be judged that there is a foreign object. In this case, the wireless power transmitter 610 sends a NAK packet as a response to the received power packet to the wireless power receiver 620 in order to stop charging. The wireless power transmitter 610 can perform the second foreign object detection (S622). As an example, the wireless power transmitter 610 uses the power value, which is the number of received power packets, and the measured transmitted power value to judge the power loss and detect whether there is a foreign object according to the power loss value. That is, when the power loss value exceeds a predetermined critical power loss value, it can be judged that there is a foreign object. In this case, the wireless power transmitter 610 sends a NAK packet as a response to the received power packet to the wireless power receiver 620 in order to stop charging. The wireless power transmitter 610 can perform the second foreign object detection (S622). As an example, the wireless power transmitter 610 uses the power value, which is the number of received power packets, and the measured transmitted power value to judge the power loss and detect whether there is a foreign object according to the power loss value. That is, when the power loss value exceeds a predetermined critical power loss value, it can be judged that there is a foreign object. In this case, the wireless power transmitter 610 sends a NAK packet as a response to the received power packet to the wireless power receiver 620 in order to stop charging. The wireless power transmitter 610 can perform the second foreign object detection (S622). As an example, the wireless power transmitter 610 uses the power value, which is the number of received power packets, and the measured transmitted power value to judge the power loss and detect whether there is a foreign object according to the power loss value. That is, when the power loss value exceeds a predetermined critical power loss value, it can be judged that there is a foreign object. In this case, the wireless power transmitter 610 sends a NAK packet as a response to the received power packet to the wireless power receiver 620 in order to stop charging. It can be transmitted (S623). Thereafter, the wireless power transmitter 610 can stop wireless charging (S624). As another example, the wireless power transmitter 610 uses the internal temperature value measured regardless of the reception of the received power packet to detect whether a foreign substance is present. That is, when the internal temperature value exceeds a predetermined critical temperature value, it can be determined that a foreign substance is present . In this case, the wireless power transmitter 610 can stop wireless charging .

[0173] Therefore, the wireless charging system according to the embodiment can provide a wireless charging method, an apparatus therefor, and a system. In addition, the wireless charging system according to the embodiment can accurately determine a foreign substance . Further, the wireless charging system according to the embodiment can accurately determine a foreign substance and prevent a heat generation phenomenon, a charging efficiency reduction phenomenon, and a waste of power consumption.

[0174] FIG. 6 is a drawing for explaining a wireless charging method in a wireless power transmitter according to an embodiment, and FIG. 7 is a drawing for explaining a foreign substance detection method according to a Q value.

[0175] Referring to FIG. 6, the wireless charging method in the wireless power transmitter can include a step of measuring a Q value before a ping step (S701). As an example, the wireless power transmitter can measure the Q value using a sensing unit in a selection step . The wireless charging method in the wireless power transmitter can include a step of receiving an FOD state packet including a reference Q value (S702). As an example, the wireless power transmitter can receive the FOD state packet using a communication unit in a negotiation step. The reference Q value is the wireless power receiver

[0176] . As an example, the wireless power transmitter can receive the FOD state packet using a communication unit in a negotiation step. The reference Q value is the wireless power receiver . ​It may be the Q value measured by a specific coil unit with the Q value stored therein. Here, the specific coil unit is a coil unit used as a reference for comparing Q values, and the wireless power transmitter must correct (calibrate) the Q value so as to be similar to the value measured by the reference coil unit according to the characteristics of the coil unit. Or, conversely, the reference Q value measured by the reference coil unit can also be corrected to the value measured by the wireless power transmitter. However, it is very difficult to correct (convert) the reference Q value to match the characteristics of the wireless power transmitter or to correct (convert) the measured value to match the specific coil unit. The Q value is an inherent characteristic value of the coil unit, and the storage and loss of energy appear differently according to the characteristics. Therefore, foreign object detection using the Q value may have errors. For example, even when only the wireless power receiver is placed within the charging area, it may be determined as a foreign object due to measurement error and / or

[0177] correction error. In a terminal equipped with a wireless power receiver such as a mobile phone, there are many components other than the wireless power receiver, and the reference Q value may be very low. If the measured Q value or the corrected Q value is greater than the reference Q value (for example, above the allowable error), a false alarm may be generated as a foreign object. Therefore, even if a foreign object is determined in the first foreign object detection stage, it is possible to determine whether a foreign object exists by an additional operation without stopping the power transmission. The wireless charging method in the wireless power transmitter includes a step (S703) of determining a critical Q value. For example, even when only the wireless power receiver is placed within the charging area, it may be determined as a foreign object due to measurement error and / or correction error. In a terminal equipped with a wireless power receiver such as a mobile phone, there are many components other than the wireless power receiver, and the reference Q value may be very low. If the measured Q value or the corrected Q value is greater than the reference Q value (for example, above the allowable error), a false alarm may be generated as a foreign object. Therefore, even if a foreign object is determined in the first foreign object detection stage, it is possible to determine whether a foreign object exists by an additional operation without stopping the power transmission. The wireless charging method in the wireless power transmitter includes a step (S703) of determining a critical Q value. For example, even when only the wireless power receiver is placed within the charging area, it may be determined as a foreign object due to measurement error and / or correction error. In a terminal equipped with a wireless power receiver such as a mobile phone, there are many components other than the wireless power receiver, and the reference Q value may be very low. If the measured Q value or the corrected Q value is greater than the reference Q value (for example, above the allowable error), a false alarm may be generated as a foreign object.

[0178] The wireless charging method in the wireless power transmitter includes a step (S703) of determining a critical Q value. is achievable. More specifically, the wireless power transmitter can calculate a critical Q value by using the received reference Q value. As an example, the wireless power transmitter can determine a value that is at least less than 10% of the reference Q value as the critical Q value at the reference Q value. 10% is the allowable error of the reference Q value. When there is a foreign object, the measured Q value is at least less than the reference Q value by the allowable error, and the foreign object can be detected by utilizing this fact.

[0179] The wireless charging method in the wireless power transmitter can include a step (S704) of determining an allowable Q value. More specifically, the wireless power transmitter can calculate the allowable Q value by using the determined critical Q value. As an example, as shown in FIG. 7, the wireless power transmitter can determine a value that has decreased by 0% or more and 20% or less at the critical Q value (Qth) as the allowable Q value (Qp). More specifically, the wireless power transmitter can determine a value that has decreased by 20% at the critical Q value as the allowable Q value.

[0180] The wireless charging method in the wireless power transmitter can include a step (S705) of determining whether the measured Q value is equal to or greater than the determined allowable Q value.

[0181] If the Q value is equal to or greater than the allowable Q value, the wireless power transmitter can determine to perform wireless charging (S706). If the Q value is less than the allowable Q value, the wireless power transmitter can determine to stop wireless charging (S714). For example, as shown in FIG. 8, when the frequency of the transmission power is the first frequency, the measured Q value of the wireless power transmitter may be the first Q value (Q1), the second Q value (Q2), or the third Q value (Q3). When it is measured as the first Q value (Q1), the wireless power transmitter ​​​​​​​​​Since the probability that there is no foreign substance between the wireless power transmitter and the wireless power receiver is very high, it can be determined that there is no foreign substance. When it is measured that it is the third Q value (Q3), since the third Q value (Q3) is much lower than the critical Q value (Qth), the probability that there is a foreign substance between the wireless power transmitter and the wireless power receiver is very high, so it can be determined that there is a foreign substance. When it is measured that it is the second Q value (Q2), since the second Q value (Q2) is between the critical Q value (Qth) and the allowable Q value (Qp), there is a risk of misrecognizing that there is a foreign substance between the wireless power transmitter and the wireless power receiver.

[0182]

[0182] When the wireless power transmitter decides to perform wireless charging, it can transmit an ACK packet to the wireless power receiver as a response to receiving the FOD status packet (S707).

[0183] After determining to perform wireless charging during the negotiation stage, it proceeds to the correction stage and decides whether to perform correction. To do this, it can determine whether the Q value is equal to or greater than the critical Q value.

[0184] The wireless charging method in the wireless power transmitter can include a stage (S709) where, if the Q value of the wireless power transmitter is equal to or greater than the critical Q value, it proceeds to the correction stage and executes correction. As an example the execution of correction can be such that the wireless power transmitter can predict power loss using the received power value of the wireless power receiver in the received power packet and the measured transmission power value. Also, the execution of correction can be such that the wireless power transmitter can increase the intensity of the transmitted power using the predicted power loss value.

[0185] The wireless charging method in the wireless power transmitter can be such that, if the Q value of the wireless power transmitter is less than the critical Q value, it can proceed to the power transmission stage (S710) without the correction stage.

[0186] The wireless charging method in the wireless power transmitter can include a stage (S711) of performing a second foreign substance detection if it receives a received power packet after proceeding to the power transmission stage. The wireless power transmitter can perform the second foreign substance detection and, if it is determined that a foreign substance has been detected, can stop the wireless charging (S712, S713). Also, the wireless power transmitter can perform the second foreign substance detection and, if it is determined that no foreign substance has been detected, can maintain the power transmission stage and, if it receives a received power packet, can perform the second foreign substance detection again (S712, S 11). As an example, during the power transmission stage, the wireless power transmitter can determine power loss using the power value, which is the number of received power packets received, and the measured transmission power value, and according to the power loss value It is possible to detect whether or not a foreign substance is present. The wireless power transmitter can determine that a foreign substance is present when the power loss value exceeds a predetermined critical power loss value. In this case , in order to stop charging, the wireless power transmitter can transmit a NAK packet to the wireless power receiver as a response to the received power packet. Thereafter, the wireless power transmitter can stop wireless charging. As another example, the wireless power transmitter can detect whether or not a foreign substance is present by using the internal temperature value measured regardless of the presence or absence of the received power packet. That is, when the internal temperature value exceeds a predetermined critical temperature value, it can be determined that a foreign substance is present . In this case, the wireless power transmitter can stop wireless charging. Thus, in one embodiment, even when foreign substance detection is suspected at the negotiation stage, wireless charging is not stopped, and after wireless charging is performed, foreign substance detection is performed again at the power transmission stage to accurately determine whether or not a foreign substance is present. After the wireless power transmitter decides to stop wireless charging in S714, it can transmit a NAK packet to the wireless power receiver as a response to the reception of the FOD status packet (S715). Thereafter, the wireless power transmitter can stop wireless charging (S713).

[0187]

[0188]

[0189] FIG. 8 is a diagram for explaining a wireless charging method in a wireless power transmitter according to another embodiment, and FIG. 9 is a diagram for explaining a foreign substance detection method according to a peak frequency value.

[0189] Referring to FIG. 8, the wireless charging method in the wireless power transmitter can include a step (S901) of measuring a peak frequency value before the ping stage. As an example, the wireless power transmitter , the peak frequency value of the transmission power can be measured using the sensing unit in the selection stage .

[0190] The wireless charging method in the wireless power transmitter can include the step (S902) of receiving an FOD state packet including a reference peak frequency value. As an example, the wireless power transmitter can receive the FOD state packet using the communication unit in the negotiation stage. The reference peak frequency value may be the peak frequency value of the received power stored in the wireless power receiver. The wireless charging method in the wireless power transmitter can include the step (S903) of determining a critical peak frequency value. More specifically, the wireless power transmitter can calculate the critical peak frequency value using the received reference peak frequency value. As an example, the wireless power transmitter can determine a value increased by 10% at the reference peak frequency value as the critical peak frequency value. 10% is the allowable error of the reference peak frequency value. When there is a foreign object, the measured peak frequency value is at least greater than the reference peak frequency value by the allowable error, and this can be used to detect the foreign object. The wireless charging method in the wireless power transmitter can include the step (S904) of determining an allowable peak frequency value. More specifically, the wireless power transmitter can calculate the allowable peak frequency value using the determined critical peak frequency value. As an example, as shown in FIG. 9, the wireless power transmitter can determine a value increased by 0% or more and 20% or less at the critical peak frequency value (Fth) as the allowable peak frequency value (fp). More specifically, the wireless The wireless charging method in the wireless power transmitter can include the step (S903) of determining a critical peak frequency value. More specifically, the wireless power transmitter can calculate the critical peak frequency value using the received reference peak frequency value. As an example, the wireless power transmitter can determine a value increased by 10% at the reference peak frequency value as the critical peak frequency value. 10% is the allowable error of the reference peak frequency value. When there is a foreign object, the measured peak frequency value is at least greater than the reference peak frequency value by the allowable error, and this can be used to detect the foreign object.

[0191] The wireless charging method in the wireless power transmitter can include the step (S903) of determining a critical peak frequency value. More specifically, the wireless power transmitter can calculate the critical peak frequency value using the received reference peak frequency value. As an example, the wireless power transmitter can determine a value increased by 10% at the reference peak frequency value as the critical peak frequency value. 10% is the allowable error of the reference peak frequency value. When there is a foreign object, the measured peak frequency value is at least greater than the reference peak frequency value by the allowable error, and this can be used to detect the foreign object. The wireless charging method in the wireless power transmitter can include the step (S903) of determining a critical peak frequency value. More specifically, the wireless power transmitter can calculate the critical peak frequency value using the received reference peak frequency value. As an example, the wireless power transmitter can determine a value increased by 10% at the reference peak frequency value as the critical peak frequency value. 10% is the allowable error of the reference peak frequency value. When there is a foreign object, the measured peak frequency value is at least greater than the reference peak frequency value by the allowable error, and this can be used to detect the foreign object. The wireless charging method in the wireless power transmitter can include the step (S903) of determining a critical peak frequency value. More specifically, the wireless power transmitter can calculate the critical peak frequency value using the received reference peak frequency value. As an example, the wireless power transmitter can determine a value increased by 10% at the reference peak frequency value as the critical peak frequency value. 10% is the allowable error of the reference peak frequency value. When there is a foreign object, the measured peak frequency value is at least greater than the reference peak frequency value by the allowable error, and this can be used to detect the foreign object. The wireless charging method in the wireless power transmitter can include the step (S903) of determining a critical peak frequency value. More specifically, the wireless power transmitter can calculate the critical peak frequency value using the received reference peak frequency value. As an example, the wireless power transmitter can determine a value increased by 10% at the reference peak frequency value as the critical peak frequency value. 10% is the allowable error of the reference peak frequency value. When there is a foreign object, the measured peak frequency value is at least greater than the reference peak frequency value by the allowable error, and this can be used to detect the foreign object. The wireless charging method in the wireless power transmitter can include the step (S903) of determining a critical peak frequency value. More specifically, the wireless power transmitter can calculate the critical peak frequency value using the received reference peak frequency value. As an example, the wireless power transmitter can determine a value increased by 10% at the reference peak frequency value as the critical peak frequency value. 10% is the allowable error of the reference peak frequency value. When there is a foreign object, the measured peak frequency value is at least greater than the reference peak frequency value by the allowable error, and this can be used to detect the foreign object. The wireless charging method in the wireless power transmitter can include the step (S903) of determining a critical peak frequency value. More specifically, the wireless power transmitter can calculate the critical peak frequency value using the received reference peak frequency value. As an example, the wireless power transmitter can determine a value increased by 10% at the reference peak frequency value as the critical peak frequency value. 10% is the allowable error of the reference peak frequency value. When there is a foreign object, the measured peak frequency value is at least greater than the reference peak frequency value by the allowable error, and this can be used to detect the foreign object. The wireless charging method in the wireless power transmitter can include the step (S903) of determining a critical peak frequency value. More specifically, the wireless power transmitter can calculate the critical peak frequency value using the received reference peak frequency value. As an example, the wireless power transmitter can determine a value increased by 10% at the reference peak frequency value as the critical peak frequency value. 10% is the allowable error of the reference peak frequency value. When there is a foreign object, the measured peak frequency value is at least greater than the reference peak frequency value by the allowable error, and this can be used to detect the foreign object.

[0192] The wireless charging method in the wireless power transmitter can include the step (S904) of determining an allowable peak frequency value. More specifically, the wireless power transmitter can calculate the allowable peak frequency value using the determined critical peak frequency value. As an example, as shown in FIG. 9, the wireless power transmitter can determine a value increased by 0% or more and 20% or less at the critical peak frequency value (Fth) as the allowable peak frequency value (fp). More specifically, the wireless The wireless charging method in the wireless power transmitter can include the step (S904) of determining an allowable peak frequency value. More specifically, the wireless power transmitter can calculate the allowable peak frequency value using the determined critical peak frequency value. As an example, as shown in FIG. 9, the wireless power transmitter can determine a value increased by 0% or more and 20% or less at the critical peak frequency value (Fth) as the allowable peak frequency value (fp). More specifically, the wireless The wireless charging method in the wireless power transmitter can include the step (S904) of determining an allowable peak frequency value. More specifically, the wireless power transmitter can calculate the allowable peak frequency value using the determined critical peak frequency value. As an example, as shown in FIG. 9, the wireless power transmitter can determine a value increased by 0% or more and 20% or less at the critical peak frequency value (Fth) as the allowable peak frequency value (fp). More specifically, the wireless The wireless charging method in the wireless power transmitter can include the step (S904) of determining an allowable peak frequency value. More specifically, the wireless power transmitter can calculate the allowable peak frequency value using the determined critical peak frequency value. As an example, as shown in FIG. 9, the wireless power transmitter can determine a value increased by 0% or more and 20% or less at the critical peak frequency value (Fth) as the allowable peak frequency value (fp). More specifically, the wireless The wireless charging method in the wireless power transmitter can include the step (S904) of determining an allowable peak frequency value. More specifically, the wireless power transmitter can calculate the allowable peak frequency value using the determined critical peak frequency value. As an example, as shown in FIG. 9, the wireless power transmitter can determine a value increased by 0% or more and 20% or less at the critical peak frequency value (Fth) as the allowable peak frequency value (fp). More specifically, the wireless The power transmitter can determine the allowable peak frequency value as a value increased by 20% at the critical peak frequency value. and can be determined.

[0193] The wireless charging method in the wireless power transmitter can include a step (S905) of determining whether the measured peak frequency value is equal to or less than the determined allowable peak frequency value. and can be included.

[0194] If the peak frequency value of the wireless power transmitter is equal to or less than the allowable peak frequency value, the wireless power transmitter can determine to perform wireless charging (S906). If the peak frequency value of the wireless power transmitter exceeds the allowable peak frequency value, the wireless power transmitter can determine to stop wireless charging (S914). For example, as shown in FIG. 9, the measured peak frequency of the wireless power transmitter may be the first peak frequency value (f1), the second peak frequency value (f2), and the third peak frequency value (f3). When the measured value is the first peak frequency value (f1), since the probability that there is no foreign substance between the wireless power transmitter and the wireless power receiver is very high, it can be determined that there is no foreign substance. When the measured value is the third peak frequency value (f3), since the third peak frequency value (f3) is much higher than the critical peak frequency value (Fth), the probability that there is a foreign substance between the wireless power transmitter and the wireless power receiver is very high, so it can be determined that there is a foreign substance. When the measured value is the second peak frequency value (f2), since the second peak frequency value (f2) is between the critical peak frequency value (Qth) and the allowable peak frequency value (fp), there is a risk of misrecognizing that there is a foreign substance between the wireless power transmitter and the wireless power receiver. To prevent this, if the measured peak frequency value of the wireless power transmitter is equal to or greater than the allowable peak frequency value, the wireless power transmitter can perform wireless charging. 9, the measured peak frequency of the wireless power transmitter may be the first peak frequency value (f1), the second peak frequency value (f2), and the third peak frequency value (f3). When the measured value is the first peak frequency value (f1), since the probability that there is no foreign substance between the wireless power transmitter and the wireless power receiver is very high, it can be determined that there is no foreign substance. When the measured value is the third peak frequency value (f3), since the third peak frequency value (f3) is much higher than the critical peak frequency value (Fth), the probability that there is a foreign substance between the wireless power transmitter and the wireless power receiver is very high, so it can be determined that there is a foreign substance. When the measured value is the second peak frequency value (f2), since the second peak frequency value (f2) is between the critical peak frequency value (Qth) and the allowable peak frequency value (fp), there is a risk of misrecognizing that there is a foreign substance between the wireless power transmitter and the wireless power receiver. To prevent this, if the measured peak frequency value of the wireless power transmitter is equal to or greater than the allowable peak frequency value, the wireless power transmitter can perform wireless charging. 9, the measured peak frequency of the wireless power transmitter may be the first peak frequency value (f1), the second peak frequency value (f2), and the third peak frequency value (f3). When the measured value is the first peak frequency value (f1), since the probability that there is no foreign substance between the wireless power transmitter and the wireless power receiver is very high, it can be determined that there is no foreign substance. When the measured value is the third peak frequency value (f3), since the third peak frequency value (f3) is much higher than the critical peak frequency value (Fth), the probability that there is a foreign substance between the wireless power transmitter and the wireless power receiver is very high, so it can be determined that there is a foreign substance. When the measured value is the second peak frequency value (f2), since the second peak frequency value (f2) is between the critical peak frequency value (Qth) and the allowable peak frequency value (fp), there is a risk of misrecognizing that there is a foreign substance between the wireless power transmitter and the wireless power receiver. To prevent this, if the measured peak frequency value of the wireless power transmitter is equal to or greater than the allowable peak frequency value, the wireless power transmitter can perform wireless charging. 2 peak frequency value (f2), and the third peak frequency value (f3). When the measured value is the first peak frequency value (f1), since the probability that there is no foreign substance between the wireless power transmitter and the wireless power receiver is very high, it can be determined that there is no foreign substance. When the measured value is the third peak frequency value (f3), since the third peak frequency value (f3) is much higher than the critical peak frequency value (Fth), the probability that there is a foreign substance between the wireless power transmitter and the wireless power receiver is very high, so it can be determined that there is a foreign substance. When the measured value is the second peak frequency value (f2), since the second peak frequency value (f2) is between the critical peak frequency value (Qth) and the allowable peak frequency value (fp), there is a risk of misrecognizing that there is a foreign substance between the wireless power transmitter and the wireless power receiver. To prevent this, if the measured peak frequency value of the wireless power transmitter is equal to or greater than the allowable peak frequency value, the wireless power transmitter can perform wireless charging. When measured as the value (f1), since the probability that there is no foreign substance between the wireless power transmitter and the wireless power receiver is very high, it can be determined that there is no foreign substance. When measured as the value (f1), since the probability that there is no foreign substance between the wireless power transmitter and the wireless power receiver is very high, it can be determined that there is no foreign substance. When measured as the third peak frequency value (f3), since the third peak frequency value (f3) is much higher than the critical peak frequency value (Fth), the probability that there is a foreign substance between the wireless power transmitter and the wireless power receiver is very high, so it can be determined that there is a foreign substance. When measured as the third peak frequency value (f3), since the third peak frequency value (f3) is much higher than the critical peak frequency value (Fth), the probability that there is a foreign substance between the wireless power transmitter and the wireless power receiver is very high, so it can be determined that there is a foreign substance. When measured as the third peak frequency value (f3), since the third peak frequency value (f3) is much higher than the critical peak frequency value (Fth), the probability that there is a foreign substance between the wireless power transmitter and the wireless power receiver is very high, so it can be determined that there is a foreign substance. When measured as the second peak frequency value (f2), since the second peak frequency value (f2) is between the critical peak frequency value (Qth) and the allowable peak frequency value (fp), there is a risk of misrecognizing that there is a foreign substance between the wireless power transmitter and the wireless power receiver. When measured as the second peak frequency value (f2), since the second peak frequency value (f2) is between the critical peak frequency value (Qth) and the allowable peak frequency value (fp), there is a risk of misrecognizing that there is a foreign substance between the wireless power transmitter and the wireless power receiver. To prevent this, if the measured peak frequency value of the wireless power transmitter is equal to or greater than the allowable peak frequency value, the wireless power transmitter can perform wireless charging. To prevent this, if the measured peak frequency value of the wireless power transmitter is equal to or greater than the allowable peak frequency value, the wireless power transmitter can perform wireless charging. can be achieved. Subsequently, the wireless power transmitter performs second foreign object detection during the power transmission stage of S911 to more accurately determine whether a foreign object exists. Therefore, if the peak frequency value is less than or equal to the allowable peak frequency value, the wireless power transmitter can decide to perform wireless charging This enables another embodiment to accurately determine foreign objects. Also Another embodiment can accurately determine foreign objects and prevent heat generation, reduction of charging efficiency, and waste of power consumption. Additionally, another embodiment can solve the problem that wireless charging is not performed due to a misrecognition of the presence of a foreign object in the past When the wireless power transmitter decides to perform wireless charging, it can transmit an ACK packet to the wireless power receiver as a response to receiving the FOD status packet (S907) The wireless charging method in the wireless power transmitter can include a step (S908) of determining whether the peak frequency value is less than or equal to the critical peak frequency value. More specifically after deciding to perform wireless charging during the negotiation stage, the wireless power transmitter transitions to the correction stage and can determine whether the peak frequency value is less than or equal to the critical peak frequency value to decide whether to perform correction

[0195] The wireless charging method in the wireless power transmitter can include a step (S909) of transitioning to the correction stage and executing correction if the peak frequency value is less than or equal to the critical peak frequency value. As an example, when executing correction, the wireless power transmitter can predict power loss by using the received power value of the wireless power receiver in the received power packet and the measured transmitted power value

[0196] The wireless charging method in the wireless power transmitter can include a step (S908) of determining whether the peak frequency value is less than or equal to the critical peak frequency value. More specifically after deciding to perform wireless charging during the negotiation stage, the wireless power transmitter transitions to the correction stage and can determine whether the peak frequency value is less than or equal to the critical peak frequency value to decide whether to perform correction

[0197] The wireless charging method in the wireless power transmitter can include a step (S909) of transitioning to the correction stage and executing correction if the peak frequency value is less than or equal to the critical peak frequency value. As an example, when executing correction, the wireless power transmitter can predict power loss by using the received power value of the wireless power receiver in the received power packet and the measured transmitted power value This enables another embodiment to accurately determine foreign objects. Also ​​​​​​, the correction execution can increase the intensity of the transmission power by using the predicted power loss value of the wireless power transmitter. It can be made to do so.

[0198] The wireless charging method in the wireless power transmitter is such that when the peak frequency value of the wireless power transmitter exceeds the critical peak frequency value, it can shift to the power transmission stage (S910) without a correction stage. It can shift to the power transmission stage without a correction stage when the peak frequency value of the wireless power transmitter exceeds the critical peak frequency value.

[0199] The wireless charging method in the wireless power transmitter can include a second foreign substance detection step (S911) if a received power packet is received after shifting to the power transmission stage. If the wireless power transmitter performs the second foreign substance detection and determines that a foreign substance has been detected, it can stop the wireless charging (S912, S913). Also, if the wireless power transmitter performs the second foreign substance detection and determines that no foreign substance has been detected, it can maintain the power transmission stage and, if it receives a received power packet, can perform the second foreign substance detection again (S912, S911). As an example, in the power transmission stage, the wireless power transmitter can determine the power loss by using the power value, which is the number of received power packets received, and the measured transmission power value, and can detect whether a foreign substance exists according to the power loss value. If the power loss value exceeds a predetermined critical power loss value, the wireless power transmitter can determine that a foreign substance exists. In this case, the wireless power transmitter can transmit a NAK packet to the wireless power receiver as a response to the received power packet in order to stop the charging. After that, the wireless power transmitter can stop the wireless charging. As another example, the wireless power transmitter can detect whether a foreign substance exists by using the internal temperature value measured regardless of the presence or absence of the received power packet. If it receives a received power packet after shifting to the power transmission stage, it can include a second foreign substance detection step (S911). The wireless power transmitter can stop the wireless charging if it performs the second foreign substance detection and determines that a foreign substance has been detected (S912, S913). Also, if the wireless power transmitter performs the second foreign substance detection and determines that no foreign substance has been detected, it can maintain the power transmission stage and, if it receives a received power packet, can perform the second foreign substance detection again (S912, S911). As an example, in the power transmission stage, the wireless power transmitter can determine the power loss by using the power value, which is the number of received power packets received, and the measured transmission power value, and can detect whether a foreign substance exists according to the power loss value. If the power loss value exceeds a predetermined critical power loss value, the wireless power transmitter can determine that a foreign substance exists. In this case, the wireless power transmitter can transmit a NAK packet to the wireless power receiver as a response to the received power packet in order to stop the charging. After that, the wireless power transmitter can stop the wireless charging. As another example, the wireless power transmitter can detect whether a foreign substance exists by using the internal temperature value measured regardless of the presence or absence of the received power packet. If the wireless power transmitter performs the second foreign substance detection and determines that a foreign substance has been detected, it can stop the wireless charging. Also, if the wireless power transmitter performs the second foreign substance detection and determines that no foreign substance has been detected, it can maintain the power transmission stage and, if it receives a received power packet, can perform the second foreign substance detection again. If the wireless power transmitter performs the second foreign substance detection and determines that no foreign substance has been detected, it can maintain the power transmission stage and, if it receives a received power packet, can perform the second foreign substance detection again. If it receives a received power packet, it can perform the second foreign substance detection again. As an example, in the power transmission stage, the wireless power transmitter can determine the power loss by using the power value, which is the number of received power packets received, and the measured transmission power value, and can detect whether a foreign substance exists according to the power loss value. If the power loss value exceeds a predetermined critical power loss value, the wireless power transmitter can determine that a foreign substance exists. In this case, the wireless power transmitter can transmit a NAK packet to the wireless power receiver as a response to the received power packet in order to stop the charging. After that, the wireless power transmitter can stop the wireless charging. As another example, the wireless power transmitter can detect whether a foreign substance exists by using the internal temperature value measured regardless of the presence or absence of the received power packet. After that, the wireless power transmitter can stop the wireless charging. As another example, the wireless power transmitter can detect whether a foreign substance exists by using the internal temperature value measured regardless of the presence or absence of the received power packet. The wireless power transmitter can detect whether a foreign substance exists by using the internal temperature value measured regardless of the presence or absence of the received power packet. It is possible. That is, when the internal temperature value exceeds a predetermined critical temperature value, it is determined that a foreign substance is present. It can be done. In this case, the wireless power transmitter can stop wireless charging. Thus, Another example is that even when foreign substance detection is suspected during the negotiation stage, wireless charging is not stopped, and after wireless charging is performed, foreign substance detection is performed again during the power transmission stage to accurately determine whether a foreign substance is present. It can be accurately determined.

[0200] When the wireless power transmitter decides to stop wireless charging in S914, it can transmit a NAK packet to the wireless power receiver as a response to receiving an FOD status packet (S9 15). Thereafter, the wireless power transmitter can stop wireless charging (S913).

[0201] FIG. 10 is a diagram for explaining a wireless charging method in a wireless power transmitter according to still another example, and FIG. 11 is a diagram for explaining a foreign substance detection method according to the equivalent series resistance value.

[0202] Referring to FIG. 10, the wireless charging method in the wireless power transmitter may include a step of measuring an equivalent series resistance value before the ping step (S1101). As an example, the wireless power transmitter can measure the equivalent series resistance value using a sensing unit in the selection step.

[0203] The wireless charging method in the wireless power transmitter may include a step of receiving an FOD status packet including a reference Q value and a reference peak frequency value (S1102). As an example, the wireless power transmitter can receive an FOD status packet using a communication unit in the negotiation step. The reference Q value and the reference peak frequency value may be the Q value and the peak frequency value stored in the wireless power receiver. ​

[0204] The wireless charging method in the wireless power transmitter includes a step of determining a critical equivalent series resistance (S11 03). More specifically, the wireless power transmitter may include a received reference Q value and The reference equivalent series resistance value can be determined by using the reference peak frequency value. In other words, the standard equivalent series resistance (ESRr) is the standard peak frequency (fr), the standard Q value (Qr) The reference inductance value (Lr) can be calculated by substituting the reference inductance value (Lr) into Equation 2. For reference, the reference inductance value (Lr) is the fixed capacitance of the wireless power receiver. The peak frequency can be determined using the received reference peak frequency value (Cr) and the received reference peak frequency value (fr).

[0205] (Formula 2) TIFF0007705975000002.tif2460(Formula 3) TIFF0007705975000003.tif2556As an example, a wireless power transmitter uses a 10% increase in the reference equivalent series resistance as a critical value. It can be determined as the equivalent series resistance (ESRth). The machine uses the maximum value of the reference equivalent series resistance (ESRmax) as the critical equivalent series resistance (ESRth). The 10% is the tolerance of the reference equivalent series resistance value, and it can be determined by the presence of foreign matter. When the resistance is measured, the measured equivalent series resistance shall be greater than the reference equivalent series resistance by at least the allowable error. This can be used to detect foreign substances.

[0206] The wireless charging method in the wireless power transmitter includes a step of determining an allowable equivalent series resistance (S11 04). More specifically, the wireless power transmitter may include a determined critical equivalent current The allowable equivalent series resistance value can be calculated using the column resistance value. As an example, as shown in FIG. 12, the wireless power transmitter can determine that the value increased by 0% or more and 20% or less at the critical equivalent series resistance value (ESRth) is the allowable equivalent series resistance value (ESRp). More specifically, the wireless power transmitter can determine that the value increased by 20% at the critical equivalent series resistance value is the allowable equivalent series resistance value.

[0207] The wireless charging method in the wireless power transmitter can include a step (S1105) of determining whether the measured equivalent series resistance value is less than or equal to the determined allowable equivalent series resistance value.

[0208] If the equivalent series resistance value of the wireless power transmitter is less than or equal to the allowable equivalent series resistance value, the wireless power transmitter can determine to perform wireless charging (S1106). If the equivalent series resistance value of the wireless power transmitter exceeds the allowable equivalent series resistance value, the wireless power transmitter can determine to stop wireless charging (S1114). For example, as shown in FIG. 11, the wireless power transmitter can use the measured equivalent series resistance value as the first equivalent series resistance value ( ESR1), the second equivalent series resistance value (ESR2), and the third equivalent series resistance value (ESR3). When the measured value is the first equivalent series resistance value (ESR1), since the probability that there is no foreign substance between the wireless power transmitter and the wireless power receiver is very high, it can be determined that there is no foreign substance. When the measured value is the third equivalent series resistance value (ESR3), since the third equivalent series resistance value (ESR3) is much higher than the critical equivalent series resistance value (ESRth), the probability that there is a foreign substance between the wireless power transmitter and the wireless power receiver is very high, so it can be determined that there is a foreign substance. When the measured value is the second equivalent series resistance value (ESR2), the second equivalent series resistance value (ESR2) resistance value (ESR3) is much higher than the critical equivalent series resistance value (ESRth), the probability that there is a foreign substance between the wireless power transmitter and the wireless power receiver is very high, so it can be determined that there is a foreign substance. When the measured value is the second equivalent series resistance value (ESR2), the second equivalent series resistance value (ESR2) The value of the series resistance (ESR2) is between the critical equivalent series resistance value (ESRth) and the allowable equivalent series resistance value (ES Rp), so if a foreign substance exists between the wireless power transmitter and the wireless power receiver, there is a risk of misrecognition identification. To prevent this, if the measured equivalent series resistance value is greater than or equal to the allowable equivalent series resistance value, wireless charging can be performed. Thereafter, the wireless power transmitter performs a second foreign substance detection in the power transmission stage of S1111 to more accurately determine whether a foreign substance exists or not. Therefore, if the equivalent series resistance value is less than or equal to the allowable equivalent series resistance value, the wireless power transmitter can determine to perform wireless charging. As a result , another embodiment can more accurately determine a foreign substance. Also, another embodiment can accurately determine a foreign substance and prevent heat generation, a decrease in charging efficiency, and waste of power consumption . Also, another embodiment can solve the problem that wireless charging is not performed due to misrecognition of the presence of a foreign substance in the past.

[0209] When the wireless power transmitter determines to perform wireless charging, it can transmit an ACK packet to the wireless power receiver as a response to the reception of the FOD status packet (S1107).

[0210] The wireless charging method in the wireless power transmitter can include a step (S1108) of determining whether the equivalent series resistance value is less than or equal to the critical equivalent series resistance value. More specifically , after the wireless power transmitter determines to perform wireless charging in the negotiation stage, it moves to the correction stage and determines whether to perform correction by determining whether the equivalent series resistance value is less than or equal to the critical equivalent series resistance value .

[0211] ​​​​The wireless charging method in the wireless power transmitter includes a step (S1109) of shifting to the correction stage and performing correction if the equivalent series resistance value of the wireless power transmitter is less than or equal to the critical equivalent series resistance value. As an example, in performing the correction, the wireless power transmitter can predict the power loss by using the received power value of the wireless power receiver in the received power packet and the measured transmission power value. Fur thermore, in performing the correction, the wireless power transmitter can increase the intensity of the transmission power by using the predicted power loss value. The wireless charging method in the wireless power transmitter includes a step (S1109) of shifting to the correction stage and performing correction if the equivalent series resistance value of the wireless power transmitter is less than or equal to the critical equivalent series resistance value. As an example, in performing the correction, the wireless power transmitter can predict the power loss by using the received power value of the wireless power receiver in the received power packet and the measured transmission power value. Fur thermore, in performing the correction, the wireless power transmitter can increase the intensity of the transmission power by using the predicted power loss value.

[0212] The wireless charging method in the wireless power transmitter can shift to the power transmission stage (S910) without the correction stage if the equivalent series resistance value of the wireless power transmitter exceeds the critical equivalent series resistance value.

[0213] The wireless charging method in the wireless power transmitter can include a step (S1111) of performing a second foreign object detection if a received power packet is received after shifting to the power transmission stage. If the wireless power trans mitter performs the second foreign object detection and determines that a foreign object is detected, the wireless charging can be stopped (S1112, S1113). Further, if the wireless power transmitter performs the second foreign object detection and determines that no foreign object is detected, the power transmission stage can be maintained, and if a received power packet is received, the second foreign object detection can be performed again (S111 2, S1111). As an example, in the power transmission stage, the wireless power transmitter can determine the power loss by using the power value, which is the number of received power packets received, and the measured transmission power value, and can detect whether a foreign object exists according to the power loss value. If the power loss value of the wireless power transmitter exceeds a predetermined critical power loss value, it can be determined that a foreign object exists. The wireless charging method in the wireless power transmitter can include a step (S1111) of performing a second foreign object detection if a received power packet is received after shifting to the power transmission stage. If the wireless power trans mitter performs the second foreign object detection and determines that a foreign object is detected, the wireless charging can be stopped (S1112, S1113). Further, if the wireless power transmitter performs the second foreign object detection and determines that no foreign object is detected, the power transmission stage can be maintained, and if a received power packet is received, the second foreign object detection can be performed again (S111 2, S1111). As an example, in the power transmission stage, the wireless power transmitter can determine the power loss by using the power value, which is the number of received power packets received, and the measured transmission power value, and can detect whether a foreign object exists according to the power loss value. If the power loss value of the wireless power transmitter exceeds a predetermined critical power loss value, it can be determined that a foreign object exists. The wireless charging method in the wireless power transmitter can include a step (S1111) of performing a second foreign object detection if a received power packet is received after shifting to the power transmission stage. If the wireless power trans mitter performs the second foreign object detection and determines that a foreign object is detected, the wireless charging can be stopped (S1112, S1113). Further, if the wireless power transmitter performs the second foreign object detection and determines that no foreign object is detected, the power transmission stage can be maintained, and if a received power packet is received, the second foreign object detection can be performed again (S111 2, S1111). As an example, in the power transmission stage, the wireless power transmitter can determine the power loss by using the power value, which is the number of received power packets received, and the measured transmission power value, and can detect whether a foreign object exists according to the power loss value. If the power loss value of the wireless power transmitter exceeds a predetermined critical power loss value, it can be determined that a foreign object exists. The wireless power transmitter can determine that a foreign object exists if the power loss value exceeds a predetermined critical power loss value. . In this case, the wireless power transmitter can transmit a NAK packet to the wireless power receiver as a response to the received power packet to stop charging. Thereafter, the wireless power transmitter can stop wireless charging. As another example, the wireless power transmitter can use the measured internal temperature value, regardless of whether the received power packet is received, to detect whether a foreign substance is present . That is, when the internal temperature value exceeds a predetermined critical temperature value, it can be determined that a foreign substance is present . In this case, the wireless power transmitter can stop wireless charging . Therefore, in yet another embodiment, even when foreign substance detection is suspected during the negotiation stage, wireless charging is performed without stopping wireless charging, and then foreign substance detection is performed again during the power transmission stage to accurately determine whether a foreign substance is present . . When the wireless power transmitter decides to stop wireless charging in S1114, it can transmit a NAK packet to the wireless power receiver as a response to the reception of the FOD status packet (S 1115). Thereafter, the wireless power transmitter can stop wireless charging (S1113).

[0214] When the wireless power transmitter decides to stop wireless charging in S1114, it can transmit a NAK packet to the wireless power receiver as a response to the reception of the FOD status packet (S 1115). Thereafter, the wireless power transmitter can stop wireless charging (S1113).

[0215] FIGS. 12A and 12B are diagrams for explaining a wireless charging method in a wireless power transmitter according to yet another embodiment.

[0216] Referring to FIGS. 12A and 12B, the wireless charging method in the wireless power transmitter can include a step of measuring a Q value, a peak frequency value, and an equivalent series resistance value before the pin grid stage (S1201) . As an example, the wireless power transmitter can measure the Q value, the peak frequency value, and the equivalent series resistance value using a sensing unit in a selection stage.

[0217] The wireless charging method in a wireless power transmitter can include the step (S1202) of receiving a FOD state packet including a reference Q value and a reference frequency value. As an example, the wireless power transmitter can receive the FOD state packet using a communication unit in a negotiation stage. The reference Q value and the reference peak frequency value may be the Q value and the peak frequency value stored in the wireless power receiver.

[0218] The wireless charging method in a wireless power transmitter can include the step (S1203) of determining a critical Q value, a critical frequency value, and a critical equivalent series resistance value. More specifically, the wireless power transmitter can calculate the critical Q value using the received reference Q value. As an example, the wireless power transmitter can determine a value that is 10% less than the reference Q value as the critical Q value. The 10% is the allowable error of the reference Q value, and when there is a foreign object, the foreign object can be detected by utilizing the fact that at least the measured Q value greater than or equal to the allowable error is smaller than the reference Q value. Also, the wireless power transmitter can calculate the critical peak frequency value using the received reference frequency value. As an example, the wireless power transmitter can determine a value that is 10% greater than the reference frequency value as the critical frequency value. The 10% is the allowable error of the reference peak frequency value, and when there is a foreign object, the foreign object can be detected by utilizing the fact that at least the measured peak frequency value greater than or equal to the allowable error is greater than the reference peak frequency value. Also, the wireless power transmitter can determine the reference equivalent series resistance value using the received reference Q value and reference peak frequency value. As an example, the wireless power transmitter can determine a value that is 10% greater than the reference equivalent series resistance value as the critical equivalent series resistance value (ESRth). As another example, ​​​​​​​​​​​​​​​​​ The wireless power transmitter can determine the maximum value of the reference equivalent series resistance (ESRmax) as the critical equivalent series resistance value (E SRth). 10% is the tolerance of the reference equivalent series resistance value. When there is a foreign substance, the measured equivalent series resistance value is at least greater than the reference equivalent series resistance value by the tolerance, and the foreign substance can be detected by utilizing this. The wireless charging method in the wireless power transmitter can include a step (S1204) of determining the allowable Q value, the allowable frequency value, and the allowable equivalent series resistance value. More specifically, the wireless power transmitter can calculate the allowable Q value by using the critical Q value determined as in S704 of FIG. 6.

[0219] The wireless power transmitter can calculate the allowable peak frequency value by using the critical peak frequency value determined as in S904 of FIG. 8. Also, the wireless power transmitter can calculate the allowable equivalent series resistance value by using the critical equivalent series resistance value determined as in S1104 of FIG. 10. The wireless charging method in the wireless power transmitter can include a step (S1205) of determining whether the measured Q value is greater than or equal to the determined allowable Q value. The wireless power transmitter can determine to abort wireless charging when the Q value is not greater than or equal to the allowable Q value (S1218).

[0220] If the Q value is greater than or equal to the allowable Q value, the wireless charging method in the wireless power transmitter can include a step (S1206) of determining whether the measured equivalent series resistance value is less than or equal to the determined allowable equivalent series resistance value. The wireless power transmitter can determine to abort wireless charging when the equivalent series resistance value is not less than or equal to the allowable equivalent series resistance value (S1218).

[0221] ​​​​​​​​​​

[0222] The wireless charging method for the wireless power transmitter requires that the equivalent series resistance is below the allowable equivalent series resistance. If so, determine whether the measured peak frequency is equal to or less than the determined allowable peak frequency. The wireless power transmitter may include a step of: If the frequency is not less than the peak frequency, it may be determined to stop wireless charging (S121 8).

[0223] The wireless charging method for the wireless power transmitter is such that the peak frequency value is below the allowable peak frequency value. If so, it can be determined to perform wireless charging (S1208). The measurement value used for detecting foreign matter may not reach the critical value that is the standard for wireless charging. If the capacity is reached, it can decide to perform wireless charging. In one embodiment, the foreign matter can be accurately determined. By accurately judging the charging status, it is possible to prevent heat generation, reduced charging efficiency, and wasteful power consumption. In addition, in still another embodiment, a wireless charging device that has been conventionally erroneously recognized as having a foreign substance is used. Not able to solve the problem.

[0224] When the wireless power transmitter decides to perform wireless charging, it responds to the FOD status packet reception. In response, an ACK packet can be transmitted to the wireless power receiver (S1209).

[0225] The wireless charging method in the wireless power transmitter is such that the Q value of the wireless power transmitter is equal to or greater than the critical Q value. The wireless power transmitter may include a step of determining whether to transmit wireless power (S1210). If the Q value of the device is not equal to or greater than the critical Q value, the device will proceed to the power transfer stage (S1214) without the correction stage. It can be done.

[0226] In the wireless power transmitter, the wireless charging method can include a step (S1211) of determining whether the equivalent series resistance value of the wireless power transmitter is greater than or equal to the critical equivalent series resistance value if the Q value is greater than or equal to the critical Q value. If the equivalent series resistance value of the wireless power transmitter is not less than the critical equivalent series resistance value, the wireless power transmitter can shift to the power transmission step (S1214) without a correction step.

[0227] In the wireless power transmitter, the wireless charging method can include a step (S1212) of determining whether the peak frequency value of the wireless power transmitter is greater than or equal to the critical peak frequency value if the equivalent series resistance value is less than or equal to the critical equivalent series resistance value. If the peak frequency value of the wireless power transmitter is not less than the critical peak frequency value, the wireless power transmitter can shift to the power transmission step (S1214) without a correction step.

[0228] In the wireless power transmitter, the wireless charging method can include a step (S1213) of shifting to a correction step and performing correction if the peak frequency value of the wireless power transmitter is less than or equal to the critical peak frequency value.

[0229] In the wireless power transmitter, the wireless charging method can include a step (S1215) of performing a second foreign object detection if a received power packet is received after shifting to the power transmission step. If the wireless power transmitter performs the second foreign object detection and determines that a foreign object is detected, the wireless charging can be stopped (S1216, S1217). If the wireless power transmitter performs the second foreign object detection and determines that no foreign object is detected, the power transmission step can be maintained. If the received power packet is received, the second foreign substance detection can be performed again (S121 6, S1215). As an example, in the power transmission stage, the wireless power transmitter uses the power value, which is the number of received power packets, and the measured transmission power value to determine the power loss, and can detect whether a foreign substance exists according to the power loss value. The wireless power transmitter can determine that a foreign substance exists when the power loss value exceeds a predetermined critical power loss value . In this case, the wireless power transmitter can transmit a NAK packet to the wireless power receiver in response to the received power packet in order to abort the charging . Thereafter, the wireless power transmitter can abort the wireless charging . As another example, the wireless power transmitter can detect whether a foreign substance exists by using the measured internal temperature value regardless of whether the received power packet is received . That is, when the internal temperature value exceeds a predetermined critical temperature value, it can be determined that a foreign substance exists . In this case, the wireless power transmitter can abort the wireless charging . Therefore, in another embodiment, even when foreign substance detection is suspected during the negotiation stage, wireless charging is not aborted, and after performing wireless charging, foreign substance detection is performed again in the power transmission stage to accurately determine whether a foreign substance exists .

[0230] When the wireless power transmitter decides to abort the wireless charging in S1218, it can transmit a NAK packet to the wireless power receiver in response to the reception of the FOD status packet (S1219). Thereafter, the wireless power transmitter can abort the wireless charging (S1217).

[0231] FIG. 13 is a diagram for explaining a wireless charging method in a wireless charging system according to still another embodiment .

[0232] Referring to FIG. 13, the wireless power transmitter 1310 can transmit an analog ping to the wireless power receiver 1320 at the selection stage (S1301). The wireless power transmitter 1310 can measure the Q value before the ping stage (S130

[0233] 2). As an example, the wireless power transmitter 1310 can measure the Q value at the selection stage ( S1302). S1302).

[0234] When an object is detected, the wireless power transmitter 1310 can transition from the selection stage to the ping stage The wireless power transmitter 1310 can activate the wireless power receiver 1320 and transmit a digital ping to identify whether the receiver is the wireless power receiver 1320 The wireless power receiver 1320 can transmit a signal strength packet in response to the digital ping (S1304). The wireless power receiver 1320 can transmit a signal strength packet in response to the digital ping (S1304). The wireless power receiver 1320 can transmit a signal strength packet in response to the digital ping (S1304).

[0235] When the ping stage is completed, in the identification and configuration stages, the wireless power receiver 1320 can transmit an identification packet to notify the identification information and a configuration packet to notify the configuration information The wireless power receiver 1320 can transmit an identification packet to notify the identification information and a configuration packet to notify the configuration information (S1305~S1306). The wireless power transmitter 1310 and the wireless power receiver 132 0 can transition to the negotiation stage if the negotiation field value of the configuration packet is the value indicating to execute the negotiation stage 0 can transition to the negotiation stage if the negotiation field value of the configuration packet is the value indicating to execute the negotiation stage In the negotiation stage, the wireless power receiver 1320 can transmit an FOD status packet to detect FO (S1307). The FOD status packet can include a reference Q value

[0236] In the negotiation stage, the wireless power receiver 1320 can transmit an FOD status packet to detect FO (S1307). The FOD status packet can include a reference Q value In the negotiation stage, the wireless power receiver 1320 can transmit an FOD status packet to detect FO (S1307). The FOD status packet can include a reference Q value In the negotiation stage, the wireless power receiver 1320 can transmit an FOD status packet to detect FO (S1307). The FOD status packet can include a reference Q value

[0237] The wireless power transmitter 1310 can perform foreign object detection (S1308). The foreign object detection can detect foreign objects by using the measured Q value and the information of the received FOD status packet. The foreign object detection can be referred to the descriptions of the wireless charging methods in FIGS. 14a and 15a.

[0238] If the wireless power transmitter 1310 determines that there is a foreign object after performing foreign object detection, it can transmit a NAK to the wireless power receiver 1320 as a response to the FOD status packet (S1309). On the contrary, if the wireless power transmitter 1310 determines that there is no foreign object after performing foreign object detection, it can transmit an ACK to the wireless power receiver 1320 as a response to the FOD status packet.

[0239] After transmitting the NAK, the wireless power transmitter 1310 can determine whether to perform wireless charging (S1310). The determination of whether to perform wireless charging can utilize the measured Q value and the information of the received FOD status packet. The determination of whether to perform wireless charging can be referred to the descriptions of the wireless charging methods in FIGS. 14a and 15b.

[0240] The wireless power receiver 1320 can transmit a general request packet requesting a power transmitter capability packet for a power transmission contract (S1311).

[0241] If the wireless power transmitter 1320 determines to perform wireless charging after transmitting the NAK, it can transmit a power transmitter capability packet as a response to the general request packet (S1312). In this case, the guaranteed power of the power transmitter capability packet is the second guaranteed power value. ​​​​​​​​​​This is also acceptable. On the other hand, if the wireless power transmitter 1320 transmits an ACK in S1309, the guaranteed power of the power transmission capability packet of the machine may be the first guaranteed power value. As an example , the first guaranteed power value may be greater than the second guaranteed power value. In particular, the second guaranteed power value may be the minimum guaranteed power intensity of the wireless power transmitter 1310. As another example, the first guaranteed power value may be between 5W and 15W. The second guaranteed power value may be 5W or less .

[0242] The wireless power receiver 1320 can transmit a special request packet for proposing the guaranteed power value of the power transmission contract based on the second guaranteed power value of the power transmitter capability packet ( S1313). It should be noted that the second guaranteed power of the power transmitter capability packet and the guaranteed power of the power transmission contract are distinct. For example, the wireless power receiver 1320 can request a guaranteed power value of the power transmission contract that is the same as or smaller than the second guaranteed power value of the power transmitter capability packet. For the sake of convenience of explanation, the wireless power receiver 1320 requests the same value as the second guaranteed power value of the power transmitter capability packet at the guaranteed power value of the power transmission contract. The wireless power transmitter 1310 can transmit an ACK packet as a response to the special request packet for requesting the guaranteed power value of the power transmission contract (S1314). That is, the wireless power transmitter 1310 accepts the guaranteed power value of the power transmission contract proposed by the wireless power receiver. That is, the power transmission contract can be completed with the second guaranteed power value. Thereafter , the wireless power receiver 1320 can transmit a special request packet for ending the negotiation stage when the power transmission contract is completed (S1315). The wireless power transmitter 1310 can receive the special request packet. The wireless power transmitter 1310 can transmit an ACK packet as a response to the special request packet for requesting the guaranteed power value of the power transmission contract (S1314). That is, the wireless power transmitter 1310 accepts the guaranteed power value of the power transmission contract proposed by the wireless power receiver. That is, the power transmission contract can be completed with the second guaranteed power value. Thereafter the wireless power receiver 1320 can transmit a special request packet for ending the negotiation stage when the power transmission contract is completed (S1315). The wireless power transmitter 1310 can receive the special request packet. That is, when the power transmission contract is completed, the wireless power receiver 1320 can transmit a special request packet to end the negotiation stage (S1315). The wireless power transmitter 1310 can receive the special request packet. That is, when the power transmission contract is completed, the wireless power receiver 1320 can transmit a special request packet to end the negotiation stage (S1315). The wireless power transmitter 1310 can receive the special request packet. That is, when the power transmission contract is completed, the wireless power receiver 1320 can transmit a special request packet to end the negotiation stage (S1315). The wireless power transmitter 1310 can Transmit an ACK packet as a response to a special request packet for ending the negotiation stage This can be done (S1316). That is, the wireless power transmitter 1310 can transmit an ACK packet as an acceptance of the end of the negotiation stage.

[0243] After transitioning to the power transmission stage, the wireless power transmitter 1310 can measure the internal temperature inside the wireless power transmitter such as in the charging area (S1317). In particular, if the wireless power transmitter 1310 transmits a NAK as a response to the FOD status packet during the negotiation stage, it can transition to the power transmission stage instead of the compensation stage after the negotiation stage ends.

[0244] The wireless power transmitter 1310 can determine whether to increase the transmission power intensity (S1319). The determination to increase the transmission power intensity can utilize the measured internal temperature, a preset fixed period, and a preset temperature. Refer to the description of the wireless charging method in Fig. 14b for the determination to increase the transmission power intensity. If the wireless power transmitter 1310 determines to increase the transmission power intensity, it can perform a re-negotiation stage. More specifically, the wireless power receiver 1320 can transmit a received power packet to the wireless power transmitter 1310 (S1319). In this case, the received power packet may be a 24-bit received power packet. If the wireless power transmitter 1310 determines to increase the transmission power intensity, it can transmit a NAK packet as a response to the received power packet (S1320). Thereafter, the wireless power transmitter 1310 can receive a re-negotiation packet and transmit an ACK packet accepting the transition to the re-negotiation stage (S1321 - S1322). The wireless power receiver 13 20 can transmit a general request packet that requests a power transmitter capability packet ( S1323). The wireless power transmitter 1310 can transmit a power transmitter function power packet as a response to the general request packet (S1324). In this case, the guaranteed power of the power transmitter capability packet may be the third guaranteed power value. As an example, the third guaranteed power value may be greater than the second guaranteed power value. As another example, the third guaranteed power value may be 5W or more and 15W or less . The wireless power receiver 1320 can transmit a special request packet for proposing a guaranteed power value of the power transmission contract based on the third guaranteed power value of the power transmitter capability packet (S1325). It should be noted that the guaranteed power of the power transmitter capability packet and the guaranteed power of the power transmission contract are distinct. For example, the wireless power receiver 1320 can propose a guaranteed power value of the power transmission contract that is the same as or smaller than the third guaranteed power value of the power transmitter capability packet. For the sake of convenience of explanation, the wireless power receiver 1320 proposes a value that is the same as the third guaranteed power value of the power transmitter capability packet at the guaranteed power value of the power transmission contract. The wireless power transmitter 1310 can transmit an ACK packet as a response to the special request packet for proposing the guaranteed power value of the power transmission contract (S1326). That is, the wireless power transmitter 1310 accepts the guaranteed power value of the power transmission contract proposed by the wireless power receiver. That is, the power transmission contract can be completed with the third guaranteed power value. . After that, the wireless power receiver 1320 can transmit a special request packet for ending the renegotiation stage when the power transmission contract is completed (S1327). The wireless power transmitter 1310 can transmit an ACK packet as a response to the special request packet for ending the renegotiation stage. That is, when the wireless power transmitter 1310 accepts the guaranteed power value of the power transmission contract proposed by the wireless power receiver. That is, the power transmission contract can be completed with the third guaranteed power value. That is, when the wireless power transmitter 1310 accepts the guaranteed power value of the power transmission contract proposed by the wireless power receiver. That is, the power transmission contract can be completed with the third guaranteed power value. After that, the wireless power receiver 1320 can transmit a special request packet for ending the renegotiation stage when the power transmission contract is completed (S1327). The wireless power transmitter 1310 can transmit an ACK packet as a response to the special request packet for ending the renegotiation stage. For the purpose of ending the renegotiation stage. The wireless power transmitter 1310 can transmit an ACK packet as a response to the special request packet for ending the renegotiation stage. It can be transmitted (S1327). That is, the wireless power transmitter 1310 can transmit an ACK packet as an acceptance for the end of the negotiation stage. The wireless power transmitter 1310 and the wireless power receiver 1320 can shift to the power transmission stage and perform wireless charging with the third guaranteed power. It can be done.

[0245] Therefore, the wireless charging system according to the embodiment can provide a wireless charging method, an apparatus therefor, and a system. Further, the wireless charging system according to the embodiment can accurately determine a foreign substance. Further, the wireless charging system according to the embodiment can accurately determine a foreign substance and prevent a heat generation phenomenon, a reduction in charging efficiency, and wasteful consumption of power. It can be prevented.

[0246] FIGS. 14a and 14b are diagrams for explaining a wireless charging method in a wireless power transmitter according to still another embodiment of FIG. 13. FIG. 15a is a diagram for explaining a foreign substance detection method of the wireless charging method of FIG. 14a, and FIG. 15b is a diagram for explaining a method of determining whether to perform wireless charging of the wireless charging method of FIG. 14a. Referring to FIGS. 14a and 14b, the wireless charging method in the wireless power transmitter may include a step of sensing an object in a charging area (S1401). More specifically, the wireless power transmitter can sense an object based on a change in the current of the transmission coil by transmitting an analog ping. It can be done.

[0247] Referring to FIGS. 14a and 14b, the wireless charging method in the wireless power transmitter may include a step of measuring a Q value before the ping step (S1 402). As an example, the wireless power transmitter may, in a selection step, sense a part by transmitting an analog ping and sensing an object based on a change in the current of the transmission coil. It can be done.

[0248] The wireless charging method in the wireless power transmitter may include a step of measuring a Q value before the ping step (S1 402). As an example, the wireless power transmitter may, in a selection step, sense a sensing unit The Q value can be measured using this.

[0249] The wireless charging method in the wireless power transmitter may include a step (S14 03) of receiving information including a reference Q value. More specifically, the wireless power transmitter can receive a FOD status packet including a reference Q value.

[0250] The wireless charging method in the wireless power transmitter may include a step (S1404~S1405) of detecting a foreign object using the measured Q value and the reference Q value. As an example, as shown in FIG. 15 a, the foreign object detection step may include a step (S1511) of determining a critical Q value. More specifically, the wireless power transmitter can calculate the critical Q value using the received reference Q value. The wireless power transmitter can determine a value less than at least 10% of the reference Q value as the critical Q value at the reference Q value. 10% is the allowable error of the reference Q value, and when there is a foreign object, the measured Q value is less than the reference Q value by at least the allowable error, and the foreign object can be detected using this. Also, the foreign object detection step may include a step (S1512) of determining whether the measured Q value is greater than the critical Q value. The wireless power transmitter can determine that no foreign object is detected if the measured Q value is greater than or equal to the critical Q value a, the foreign object detection step may include a step (S1511) of determining a critical Q value. More specifically, the wireless power transmitter can calculate the critical Q value using the received reference Q value. The wireless power transmitter can determine a value less than at least 10% of the reference Q value as the critical Q value at the reference Q value. 10% is the allowable error of the reference Q value, and when there is a foreign object, the measured Q value is less than the reference Q value by at least the allowable error, and the foreign object can be detected using this. Also, the foreign object detection step may include a step (S1512) of determining whether the measured Q value is greater than the critical Q value. The wireless power transmitter can determine that no foreign object is detected if the measured Q value is greater than or equal to the critical Q value a, the foreign object detection step may include a step (S1511) of determining a critical Q value. More specifically, the wireless power transmitter can calculate the critical Q value using the received reference Q value. The wireless power transmitter can determine a value less than at least 10% of the reference Q value as the critical Q value at the reference Q value. 10% is the allowable error of the reference Q value, and when there is a foreign object, the measured Q value is less than the reference Q value by at least the allowable error, and the foreign object can be detected using this. Also, the foreign object detection step may include a step (S1512) of determining whether the measured Q value is greater than the critical Q value. The wireless power transmitter can determine that no foreign object is detected if the measured Q value is greater than or equal to the critical Q value a, the foreign object detection step may include a step (S1511) of determining a critical Q value. More specifically, the wireless power transmitter can calculate the critical Q value using the received reference Q value. The wireless power transmitter can determine a value less than at least 10% of the reference Q value as the critical Q value at the reference Q value. 10% is the allowable error of the reference Q value, and when there is a foreign object, the measured Q value is less than the reference Q value by at least the allowable error, and the foreign object can be detected using this. Also, the foreign object detection step may include a step (S1512) of determining whether the measured Q value is greater than the critical Q value. The wireless power transmitter can determine that no foreign object is detected if the measured Q value is greater than or equal to the critical Q value a, the foreign object detection step may include a step (S1511) of determining a critical Q value. More specifically, the wireless power transmitter can calculate the critical Q value using the received reference Q value. The wireless power transmitter can determine a value less than at least 10% of the reference Q value as the critical Q value at the reference Q value. 10% is the allowable error of the reference Q value, and when there is a foreign object, the measured Q value is less than the reference Q value by at least the allowable error, and the foreign object can be detected using this. Also, the foreign object detection step may include a step (S1512) of determining whether the measured Q value is greater than the critical Q value. The wireless power transmitter can determine that no foreign object is detected if the measured Q value is greater than or equal to the critical Q value a, the foreign object detection step may include a step (S1511) of determining a critical Q value. More specifically, the wireless power transmitter can calculate the critical Q value using the received reference Q value. The wireless power transmitter can determine a value less than at least 10% of the reference Q value as the critical Q value at the reference Q value. 10% is the allowable error of the reference Q value, and when there is a foreign object, the measured Q value is less than the reference Q value by at least the allowable error, and the foreign object can be detected using this. Also, the foreign object detection step may include a step (S1512) of determining whether the measured Q value is greater than the critical Q value. The wireless power transmitter can determine that no foreign object is detected if the measured Q value is greater than or equal to the critical Q value a, the foreign object detection step may include a step (S1511) of determining a critical Q value. More specifically, the wireless power transmitter can calculate the critical Q value using the received reference Q value. The wireless power transmitter can determine a value less than at least 10% of the reference Q value as the critical Q value at the reference Q value. 10% is the allowable error of the reference Q value, and when there is a foreign object, the measured Q value is less than the reference Q value by at least the allowable error, and the foreign object can be detected using this. Also, the foreign object detection step may include a step (S1512) of determining whether the measured Q value is greater than the critical Q value. The wireless power transmitter can determine that no foreign object is detected if the measured Q value is greater than or equal to the critical Q value a, the foreign object detection step may include a step (S1511) of determining a critical Q value. More specifically, the wireless power transmitter can calculate the critical Q value using the received reference Q value. The wireless power transmitter can determine a value less than at least 10% of the reference Q value as the critical Q value at the reference Q value. 10% is the allowable error of the reference Q value, and when there is a foreign object, the measured Q value is less than the reference Q value by at least the allowable error, and the foreign object can be detected using this. Also, the foreign object detection step may include a step (S1512) of determining whether the measured Q value is greater than the critical Q value. The wireless power transmitter can determine that no foreign object is detected if the measured Q value is greater than or equal to the critical Q value a, the foreign object detection step may include a step (S1511) of determining a critical Q value. More specifically, the wireless power transmitter can calculate the critical Q value using the received reference Q value. The wireless power transmitter can determine a value less than at least 10% of the reference Q value as the critical Q value at the reference Q value. 10% is the allowable error of the reference Q value, and when there is a foreign object, the measured Q value is less than the reference Q value by at least the allowable error, and the foreign object can be detected using this. Also, the foreign object detection step may include a step (S1512) of determining whether the measured Q value is greater than the critical Q value. The wireless power transmitter can determine that no foreign object is detected if the measured Q value is greater than or equal to the critical Q value (S1513). Also, if the measured Q value is less than the critical Q value, the wireless power transmitter can determine that a foreign object is detected (S1514).

[0251] When the wireless power transmitter determines that no foreign object is detected, it can transmit an ACK to the wireless power receiver (S1406). That is, the wireless power transmitter can transmit an ACK to the wireless power receiver (S1406). That is, the wireless power transmitter Transmit an ACK packet to the wireless power receiver as a response to the reception of the FOD status packet This can be done.

[0252] The wireless charging method in the wireless power transmitter may include a step (S1407) of transmitting information including a first guaranteed power value to the wireless power transmitter if an ACK is transmitted. In this case, the wireless power transmitter concludes a power transmission contract based on the wireless power receiver and the first guaranteed power value. As an example, the first guaranteed power value may be greater than 5W.

[0253] The wireless charging method in the wireless power transmitter may include a step (S1408) of shifting to a correction stage and performing correction when transmitting information including the first guaranteed power value. As an example, the correction execution can be such that the wireless power transmitter predicts power loss using the received power value of the wireless power receiver in the received power packet and the measured transmission power value. Also, the correction execution can be such that the wireless power transmitter increases the intensity of the transmission power using the predicted power loss value.

[0254] The wireless charging method in the wireless power transmitter may include a step (S1409) of shifting to a power transmission stage after correction execution and performing wireless charging with the first guaranteed power. In this case, performing wireless charging with the first guaranteed power can mean performing wireless charging according to the guaranteed power value in the power transmission contract concluded based on the first guaranteed power value.

[0255] If it is determined in S1405 that a foreign substance is detected, the wireless charging method in the wireless power transmitter can transmit a NAK to the wireless power receiver (S1410). That is, the wireless power transmitter can transmit a NAK packet to the wireless power receiver as a response to the reception of the FOD status packet. ​It can be trusted.

[0256] The wireless charging method in the wireless power transmitter can include a step (S1411 - S1412) of determining whether to perform wireless charging when transmitting a NAK. For example, as shown in Fig. 15b The step of determining whether to perform wireless charging can include a step (S15 21) of determining an allowable Q value. More specifically, the wireless power transmitter can calculate the allowable Q value using the determined critical Q value. For example, as shown in Fig. 7, the wireless power transmitter can determine the value decreased by 0% or more and 20% or less at the critical Q value as the allowable Q value (Qp). More specifically, the wireless power transmitter can determine the value decreased by 20% at the critical Q value as the allowable Q value. The determination of whether to perform wireless charging can include a step (S1522) of determining whether the measured Q value is greater than or equal to the determined allowable Q value. The wireless power transmitter can determine to perform wireless charging if the measured Q value is greater than or equal to the allowable Q value (S1523). Also, the wireless power transmitter can determine not to perform wireless charging if the measured Q value is less than the allowable Q value (S1524). For example, as shown in Fig. 8, when the frequency of the transmission power is the first frequency, the wireless power transmitter may have the measured Q values as the first Q value (Q1), the second Q value (Q2), and the third Q value (Q3). When measured as the first Q value (Q1), since the probability that there is no foreign substance between the wireless power transmitter and the wireless power receiver is very high, it can be determined that there is no foreign substance. When measured as the third Q value (Q3), since the third Q value (Q3) is much lower than the critical Q value (Qth), the wireless power transmission ​​​​​​​​​​​​​Since the probability of foreign substances existing between the device and the wireless power receiver is very high, if foreign substances are present it can be determined. When measured as the second Q value (Q2), the second Q value (Q2) is the critical Since it is between the Q value (Qth) and the allowable Q value (Qp), there is a risk of misidentifying that there are foreign substances between the wireless power transmitter and the wireless power receiver. To prevent this, the wireless power transmitter If the measured Q value is equal to or greater than the allowable Q value, wireless charging can be performed. After that, the wireless power transmitter can re-determine whether to stop wireless charging based on the internal temperature at S1417 Thus, if the Q value is equal to or greater than the allowable Q value, the wireless power transmitter can decide to perform wireless charging As a result, another embodiment can accurately determine foreign substances Moreover, another embodiment can accurately determine foreign substances and prevent heat generation phenomena, charging efficiency reduction phenomena, and wasteful consumption of power. Additionally, another embodiment can solve the problem that wireless charging is not performed due to a misrecognition of the presence of foreign substances in the past.

[0257] The wireless charging method in the wireless power transmitter can include a step (S1413) of stopping wireless charging when the wireless power transmitter decides not to perform wireless charging More specifically, in this case, the wireless power transmitter can transition to the selection stage after a predetermined time has elapsed in the negotiation stage is possible.

[0258] The wireless charging method in the wireless power transmitter can include a step (S1414) of transmitting information including the second guaranteed power value to the wireless power receiver when it decides to perform wireless charging. In this case, based on the wireless power receiver and the second guaranteed power value, the wireless power transmitter determines that the power transmission contract It is concluded. As an example, the first guaranteed power value may be greater than the second guaranteed power value. In particular , the second guaranteed power value may be the minimum guaranteed power intensity of the wireless power transmitter. As another example , the second guaranteed power value may be 5 W or less.

[0259] In the wireless charging method in the wireless power transmitter, when transmitting the information included as the second guaranteed power value , it is possible to include a step of shifting to the power transmission stage without a correction stage and performing wireless charging with the second guaranteed power (S14 15). In this case, performing wireless charging with the second guaranteed power means performing wireless charging according to the guaranteed power value according to the power transmission contract concluded based on the second guaranteed power value.

[0260] The following is an example for detecting foreign matter in the power transmission stage after foreign matter is detected before the power transmission stage. When it is determined that foreign matter exists, since heat may be further generated by the foreign matter, it is necessary to strengthen the overheat protection means. Or, since there is also a possibility that a large amount of power is absorbed by the foreign matter, it is possible to detect the foreign matter by comparing the difference between the power received by the receiver and the transmitted power with a preset power loss value. At this time, the preset power loss value may be smaller than the power loss critical value in a state where it is determined that there is no foreign matter.

[0261] For the enhanced overheat protection means, the wireless charging method in the wireless power transmitter may include a step of measuring the temperature of the wireless power transmitter such as the charging area (S1416). The temperature of the transmitter may mean the surface temperature or the temperature sensed by a sensor inside the transmitter.

[0262] ​​​​​​​The wireless charging method in the wireless power transmitter may include a step (S1417) of determining whether the internal temperature measured during a preset period is less than a preset temperature. The preset period and the preset temperature may be stored values.

[0263] The wireless charging method in the wireless power transmitter may include a step (S1418) of stopping wireless charging when the internal temperature becomes equal to or higher than a preset temperature during a preset period. More specifically, in this case, the wireless power transmitter may shift to a selection step after a predetermined time has elapsed in the power transmission step. That is, when the internal temperature of the wireless power transmitter becomes equal to or higher than a preset temperature during a preset period, it can be determined that a foreign substance is present and wireless charging can be stopped. Or, renegotiation for reducing the transmitted power can be performed. As an example, the wireless power transmitter may transmit a NAK packet to the wireless power receiver as a response to the received received power packet, and thereafter, the wireless power transmitter may transmit a renegotiation packet to the wireless power transmitter to perform a renegotiation step. That is, if the internal temperature is equal to or higher than a preset temperature during a preset period, the wireless power transmitter can determine that a foreign substance is present and reduce the transmission power intensity.

[0264] The wireless charging method in the wireless power transmitter may include a step (S1419) of performing a renegotiation step if the internal temperature is less than a preset temperature during a preset period. As an example, the wireless power transmitter may transmit a NAK packet to the wireless power receiver as a response to the received received power packet, and thereafter, the wireless power transmitter may transmit a renegotiation packet to the wireless power transmitter It can be transmitted to the communication device to perform the renegotiation stage. That is, if the internal temperature is lower than the preset temperature during the preset period, the wireless power transmitter determines that there is no foreign substance and can increase the transmission power intensity.

[0265] When the wireless charging method in the wireless power transmitter enters the renegotiation stage, it can include the step of transmitting information including the third guaranteed power value to the wireless power receiver (S1420). In this case, the wireless power transmitter concludes a power transmission contract based on the wireless power receiver and the third guaranteed power value. As an example, the third guaranteed power value may be greater than the second guaranteed power value. As another example, the third guaranteed power value may be greater than 5W.

[0266] The wireless charging method in the wireless power transmitter can include the step of entering the power transmission stage and performing wireless charging with the third guaranteed power (S1421). In this case, performing wireless charging with the third guaranteed power can mean performing wireless charging according to the guaranteed power value in the power transmission contract concluded based on the third guaranteed power value. Thereby, the wireless power transmitter reduces the transmission power intensity to protect the system when it is determined that a foreign substance is detected during the negotiation stage, but finally increases the transmission power intensity to increase the wireless charging efficiency when it is determined that no foreign substance is detected during the power transmission stage.

[0267] As yet another embodiment, in the NAK transmission stage (S1410), the wireless power receiver can request the minimum power required for the receiver to charge the battery from the transmitter (negotiation stage).

[0268] Also, after a certain period of time, when the receiver determines that there is no foreign substance, it can perform renegotiation The guaranteed power can also be increased.

[0269] FIG. 16 illustrates a wireless charging method in a wireless charging system according to yet another embodiment. It is a drawing for this.

[0270] Referring to FIG. 16, the wireless power transmitter 1610 can transmit an analog ping to the wireless power receiver 1620 at the selection stage (S1601). The wireless power transmitter 1610 can measure the Q value before the ping stage (S160

[0271] 2). As an example, the wireless power transmitter 1610 can measure the Q value at the selection stage ( S1602). S1602).

[0272] When an object is detected, the wireless power transmitter 1610 can transition from the selection stage to the ping stage. The wireless power transmitter 1610 can activate the wireless power receiver 1620 and transmit a digital ping to identify whether the receiver is the wireless power receiver 1620. The wireless power receiver 1620 can transmit a signal strength packet in response to the digital ping (S1604). The wireless power receiver 1620 can transmit a signal strength packet in response to the digital ping (S1604). The wireless power receiver 1620 can transmit a signal strength packet in response to the digital ping (S1604).

[0273] When the ping stage is completed, at the identification and configuration stage, the wireless power receiver 1620 can transmit an identification packet for notifying identification information and a configuration packet for notifying configuration information. The wireless power receiver 1620 can transmit an identification packet for notifying identification information and a configuration packet for notifying configuration information. The wireless power transmitter 1610 and the wireless power receiver 162 0 can transition to the negotiation stage if the negotiation field value of the configuration packet is a value indicating an attempt to execute the negotiation stage. The wireless power transmitter 1610 and the wireless power receiver 162

[0274] During the negotiation stage, the wireless power receiver 1620 can transmit an FOD status packet to detect FO (S1607). The FOD status packet can include a reference Q value. The wireless power transmitter 1610 can check whether the received reference Q value is less than a preset Q value (e.g., less than 50) (S1608). If the reference Q value is less than the preset Q value, the first foreign object detection step is performed. If the reference Q value is greater than or equal to the preset Q value, the second foreign object detection step is performed. That is, the lower the reference Q value is below the set Q value, the greater the error in foreign object detection using the Q value. On the contrary, if the reference Q value is greater than or equal to the set Q value, the error in foreign object detection using the Q value is smaller. Therefore, according to the magnitude of the reference Q value, after foreign object detection, each step of the wireless power transmission method can be made different, so as to improve the accuracy of foreign object detection and reduce unnecessary power consumption. According to the magnitude of the reference Q value, after detecting a foreign object, the wireless power transmission method will be described with reference to FIGS. 17a and 17b.

[0275] If the wireless power transmitter 1610 determines that a foreign object exists after performing the first foreign object detection, it transmits a NAK to the wireless power receiver 1620 as a response to the FOD status packet. If the reference Q value is less than the preset Q value, the first foreign object detection can be performed (S1609). The first foreign object detection can detect a foreign object using the measured Q value and the information of the received FOD status packet. The first foreign object detection refers to the description of the wireless charging method in FIGS. 17a and 15a. If the reference Q value is less than the preset Q value, the first foreign object detection step is performed. If the reference Q value is greater than or equal to the preset Q value, the second foreign object detection step is performed. That is, the lower the reference Q value is below the set Q value, the greater the error in foreign object detection using the Q value. On the contrary, if the reference Q value is greater than or equal to the set Q value, the error in foreign object detection using the Q value is smaller. Therefore, according to the magnitude of the reference Q value, after foreign object detection, each step of the wireless power transmission method can be made different, so as to improve the accuracy of foreign object detection and reduce unnecessary power consumption. According to the magnitude of the reference Q value, after detecting a foreign object, the wireless power transmission method will be described with reference to FIGS. 17a and 17b. If the reference Q value is less than the preset Q value, the first foreign object detection can be performed (S1609). The first foreign object detection can detect a foreign object using the measured Q value and the information of the received FOD status packet. The first foreign object detection refers to the description of the wireless charging method in FIGS. 17a and 15a. If the reference Q value is less than the preset Q value, the first foreign object detection can be performed (S1609). The first foreign object detection can detect a foreign object using the measured Q value and the information of the received FOD status packet. The first foreign object detection refers to the description of the wireless charging method in FIGS. 17a and 15a. If the reference Q value is less than the preset Q value, the first foreign object detection can be performed (S1609). The first foreign object detection can detect a foreign object using the measured Q value and the information of the received FOD status packet. The first foreign object detection refers to the description of the wireless charging method in FIGS. 17a and 15a. If the reference Q value is less than the preset Q value, the first foreign object detection can be performed (S1609). The first foreign object detection can detect a foreign object using the measured Q value and the information of the received FOD status packet. The first foreign object detection refers to the description of the wireless charging method in FIGS. 17a and 15a. If the reference Q value is less than the preset Q value, the first foreign object detection can be performed (S1609). The first foreign object detection can detect a foreign object using the measured Q value and the information of the received FOD status packet. The first foreign object detection refers to the description of the wireless charging method in FIGS. 17a and 15a. If the reference Q value is less than the preset Q value, the first foreign object detection can be performed (S1609). The first foreign object detection can detect a foreign object using the measured Q value and the information of the received FOD status packet. The first foreign object detection refers to the description of the wireless charging method in FIGS. 17a and 15a.

[0276] If the reference Q value is less than the preset Q value, the first foreign object detection can be performed (S1609). The first foreign object detection can detect a foreign object using the measured Q value and the information of the received FOD status packet. The first foreign object detection refers to the description of the wireless charging method in FIGS. 17a and 15a. If the reference Q value is less than the preset Q value, the first foreign object detection can be performed (S1609). The first foreign object detection can detect a foreign object using the measured Q value and the information of the received FOD status packet. The first foreign object detection refers to the description of the wireless charging method in FIGS. 17a and 15a. If the reference Q value is less than the preset Q value, the first foreign object detection can be performed (S1609). The first foreign object detection can detect a foreign object using the measured Q value and the information of the received FOD status packet. The first foreign object detection refers to the description of the wireless charging method in FIGS. 17a and 15a.

[0277] After the wireless power transmitter 1610 performs the first foreign object detection and determines that a foreign object exists, it transmits a NAK to the wireless power receiver 1620 as a response to the FOD status packet. After the wireless power transmitter 1610 performs the first foreign object detection and determines that a foreign object exists, it transmits a NAK to the wireless power receiver 1620 as a response to the FOD status packet. ​​​It is possible (S1610). On the contrary, after the wireless power transmitter 1610 performs the first foreign object detection If it is determined that there is no foreign object, an ACK can be transmitted wirelessly as a response to the FOD status packet to the wireless power receiver 1620.

[0278] When the wireless power transmitter 1610 transmits a NAK, it can determine whether to perform wireless charging (S1611). The determination of whether to perform wireless charging can utilize the measured Q value and the information of the received FOD status packet. The determination of whether to perform wireless charging can refer to the description of the wireless charging method in FIGS. 16a and 15b. On the contrary, after the second foreign object detection when the wireless power transmitter 1610 transmits a NAK, wireless charging can be aborted without going through the stage of determining whether to perform wireless charging.

[0279] As yet another example, if the reference Q value is less than the preset Q value of the wireless power transmitter then wireless charging can also be aborted. And if the reference Q value is greater than or equal to the preset Q value of the wireless power transmitter, the first foreign object detection can be performed.

[0280] The wireless power receiver 1620 can transmit a general request packet requesting a power transmitter capability packet for a power transmission contract (S1612).

[0281] After the wireless power transmitter 1620 transmits a NAK and determines to perform wireless charging, it can transmit a power transmitter capability packet as a response to the general request packet (S1613). In this case, the guaranteed power of the power transmitter capability packet is the second guaranteed power value This is also acceptable. On the other hand, if the wireless power transmitter 1620 transmits an ACK in S1610, the guaranteed power of the power transmission machine capability packet may be the first guaranteed power value. As an example , the first guaranteed power value may be greater than the second guaranteed power value. In particular, the second guaranteed power value may be the minimum guaranteed power intensity of the wireless power transmitter 1610. As another example, the first guaranteed power value may be between 5W and 15W. The second guaranteed power value may be 5W or less .

[0282] The wireless power receiver 1620 can transmit a special request packet for proposing the guaranteed power value of the power transmission contract based on the second guaranteed power value of the power transmitter capability packet ( S1614). It should be noted that the second guaranteed power of the power transmitter capability packet and the guaranteed power of the power transmission contract are distinguishable. For example, the wireless power receiver 1620 can request the guaranteed power value of the power transmission contract to be the same as or smaller than the second guaranteed power value of the power transmitter capability packet. For the sake of convenience of explanation, the wireless power receiver 1620 requests the guaranteed power value of the power transmission contract to be the same as the second guaranteed power value of the power transmitter capability packet. The wireless power transmitter 1610 can transmit an ACK packet as a response to the special request packet for requesting the guaranteed power value of the power transmission contract (S1615). That is, the wireless power transmitter 1610 accepts the guaranteed power value of the power transmission contract proposed by the wireless power receiver. That is, the power transmission contract can be completed with the second guaranteed power value. After that , the wireless power receiver 1620 can transmit a special request packet for ending the negotiation stage when the power transmission contract is completed (S1616). The wireless power transmitter 1610 can communicate. The wireless power transmitter 1610 can transmit an ACK packet as a response to the special request packet for requesting the guaranteed power value of the power transmission contract (S1615). That is, the wireless power transmitter 1610 accepts the guaranteed power value of the power transmission contract proposed by the wireless power receiver. That is, the power transmission contract can be completed with the second guaranteed power value. After that The wireless power transmitter 1610 accepts the guaranteed power value of the power transmission contract proposed by the wireless power receiver. That is, the power transmission contract can be completed with the second guaranteed power value. After that , the wireless power receiver 1620 can transmit a special request packet for ending the negotiation stage when the power transmission contract is completed (S1616). The wireless power transmitter 1610 can communicate. The wireless power receiver 1620 can transmit a special request packet for ending the negotiation stage when the power transmission contract is completed (S1616). The wireless power transmitter 1610 can Transmit an ACK packet as a response to a special request packet for ending the negotiation stage This can be done (S1617). That is, the wireless power transmitter 1610 can transmit an ACK packet as an acceptance of the end of the negotiation stage.

[0283] After transitioning to the power transmission stage, the wireless power transmitter 1610 can measure the internal temperature inside the wireless power transmitter, such as in the charging area (S1618). In particular, if the wireless power transmitter 1610 transmits a NAK as a response to the FOD status packet during the negotiation stage, it can transition to the power transmission stage instead of the compensation stage after the negotiation stage ends.

[0284] The wireless power transmitter 1610 can determine whether to increase the transmission power intensity (S1619). The determination to increase the transmission power intensity can utilize the measured internal temperature, the stored preset period, and the preset temperature. Refer to the description of the wireless charging method in FIG. 17b for the determination to increase the transmission power intensity. If the wireless power transmitter 1610 determines to increase the transmission power intensity, it can perform a re-negotiation stage. More specifically, the wireless power receiver 1620 can transmit a received power packet to the wireless power transmitter 1610 (S1620). In this case, the received power packet can be a 24-bit received power packet. If the wireless power transmitter 1610 determines to increase the transmission power intensity, it can transmit a NAK packet as a response to the received power packet (S1621). Thereafter, the wireless power transmitter 1610 can receive a re-negotiation packet and transmit an ACK packet accepting the transition to the re-negotiation stage (S1622 - S1623). ​​​​​​​​​​​​​​0 can transmit a general request packet that requests a power transmitter capacity packet (S 1624). The wireless power transmitter 1610 can transmit a power transmitter capacity packet as a response to the general request packet (S1625). In this case, the guaranteed power of the power transmitter capacity packet may be the third guaranteed power value. As an example, the third guaranteed power value may be greater than the second guaranteed power value. As another example, the third guaranteed power value may be 5W or more and 15W or less. The wireless power receiver 1620 can transmit a special request packet for proposing the guaranteed power value of the power transmission contract based on the third guaranteed power value of the power transmitter capacity packet (S1626). It should be noted that the guaranteed power of the power transmitter capacity packet and the guaranteed power of the power transmission contract are distinguishable. For example, the wireless power receiver 1620 can propose the guaranteed power value of the power transmission contract to be the same as or less than the third guaranteed power value of the power transmitter capacity packet. For the sake of convenience of explanation, the wireless power receiver 1620 proposes the same value as the third guaranteed power value of the power transmitter capacity packet at the guaranteed power value of the power transmission contract. The wireless power transmitter 1610 can transmit an ACK packet as a response to the special request packet for proposing the guaranteed power value of the power transmission contract (S1627). That is, the wireless power transmitter 1610 accepts the guaranteed It can be transmitted (S1628). That is, the wireless power transmitter 1610 can transmit an ACK packet as an acceptance response to the end of the negotiation stage. The wireless power transmitter 1610 and the wireless power receiver 1620 can transition to the power transmission stage and perform wireless charging with the third guaranteed power. It can be done.

[0285] Therefore, the wireless charging system according to the embodiment can provide a wireless charging method, an apparatus therefor, and a system. Further, the wireless charging system according to the embodiment can accurately determine a foreign substance. Further, the wireless charging system according to the embodiment can accurately determine a foreign substance and prevent a heat generation phenomenon, a decrease in charging efficiency, and waste of power consumption. It can be done.

[0286] FIGS. 17A and 17B are diagrams for explaining a wireless charging method in a wireless power transmitter according to still another embodiment of FIG. 16. It is a drawing.

[0287] Referring to FIGS. 17A and 17B, the wireless charging method in the wireless power transmitter can include a step of sensing an object in the charging area (S1701). More specifically, the wireless power transmitter can transmit an analog ping and sense an object based on a current change in the transmission coil. It can be done.

[0288] The wireless charging method in the wireless power transmitter can include a step of measuring a Q value before the ping step (S1 702). As an example, the wireless power transmitter can measure the Q value using a sensing unit in a selection step. It can be done.

[0289] The wireless charging method in the wireless power transmitter can include a step of receiving information including a reference Q value (S17 It can include (03). More specifically, the wireless power transmitter includes a FOD including a reference Q value It can receive a status packet. As an example, the wireless power transmitter can communicate during the negotiation stage to receive the FOD status packet using a section. The reference Q value may be the Q value measured by a specific coil unit with the Q value stored in the wireless power receiver

[0290] The wireless charging method in the wireless power transmitter can include a step (S1704) of determining whether the reference Q value is less than a preset Q value (for example, 50 If the reference Q value is less than the preset Q value, a first foreign object detection step is performed. If the reference Q value is greater than or equal to the preset Q value a second foreign object detection step is performed. That is, the lower the reference Q value is less than the preset Q value (for example, less than 50), the greater the error of foreign object detection using the Q value becomes On the contrary, if the reference Q value is greater than or equal to the preset Q value, the error of foreign object detection using the Q value becomes smaller. Therefore, according to the magnitude of the reference Q value, after foreign object detection, each step of the wireless power transmission method is made to have a difference, so as to improve the accuracy of foreign object detection and reduce unnecessary power consumption

[0291] The wireless charging method in the wireless power transmitter, if the reference Q value is less than the preset Q value can include a step (S1705~S 1706) of detecting a first foreign object using the measured Q value and the reference Q value.

[0292] As yet another example, if the reference Q value is less than the preset Q value of the wireless power transmitter wireless charging can also be aborted. If the reference Q value is greater than or equal to the preset Q value of the wireless power transmitter the first foreign object detection can be performed.​​​​​

[0293] As yet another example, the wireless power transmitter can modulate a response signal to a foreign substance detection status packet and transmit it to the wireless power receiver as Positive acknowledge (ACK), Negative acknowledge (NAK), Not defined (ND), Cau tion (warning) signal. The ACK signal is a response signal for continuing the wireless charging procedure when there is no foreign substance. The NAK signal may be a response signal for stopping the wireless charging procedure when it is determined that a foreign substance is present. The Caution signal can be used when it is difficult to determine whether a foreign substance is present. When it is difficult to determine whether a foreign substance is present, the reference Q value of the wireless power receiver may be a preset value (for example, less than 50). When the change in the Q value is small due to friendly metal ( the phenomenon where the Q value damping due to power loss is blocked), it may be difficult to determine whether a foreign substance is present only by comparing the reference Q value and the measured Q value. At this time, the Caution signal can be transmitted, and foreign substance detection based on power loss can be performed while charging with the minimum guaranteed power. For yet another example, the Caution signal and the NAK signal can be used according to two types of reference Q value critical levels. If the reference Q value received from the wireless power receiver is between a preset first Q value critical value and a preset second Q value critical value (smaller than the first critical value), the first foreign substance detection is performed, and if it is determined that a foreign substance is present as a result of the first foreign substance detection, the Caution signal can be transmitted. If the received reference Q value is smaller than the second Q value critical value, the NAK signal can be transmitted. the phenomenon where the Q value damping due to power loss is blocked), it may be difficult to determine whether a foreign substance is present only by comparing the reference Q value and the measured Q value. At this time, the Caution signal can be transmitted, and foreign substance detection based on power loss can be performed while charging with the minimum guaranteed power. the Caution signal can be transmitted, and foreign substance detection based on power loss can be performed while charging with the minimum guaranteed power. the Caution signal can be transmitted, and foreign substance detection based on power loss can be performed while charging with the minimum guaranteed power.

[0294] As yet another example, the Caution signal and the NAK signal can be used according to two types of reference Q value critical levels. If the reference Q value received from the wireless power receiver is between a preset first Q value critical value and a preset second Q value critical value (smaller than the first critical value), the first foreign substance detection is performed, and if it is determined that a foreign substance is present as a result of the first foreign substance detection, the Caution signal can be transmitted. If the received reference Q value is smaller than the second Q value critical value, the NAK signal can be transmitted. between a preset first Q value critical value and a preset second Q value critical value (smaller than the first critical value), the first foreign substance detection is performed, and if it is determined that a foreign substance is present as a result of the first foreign substance detection, the Caution signal can be transmitted. If the received reference Q value is smaller than the second Q value critical value, the NAK signal can be transmitted. the Caution signal can be transmitted. If the received reference Q value is smaller than the second Q value critical value, the NAK signal can be transmitted. the NAK signal can be transmitted.

[0295] For example, as shown in FIG. 15a, the foreign matter detection step may include a step of determining a critical Q value (S15 11). More specifically, the wireless power transmitter uses the received reference Q value to The critical Q value can be calculated using the above formula. In any case, a value smaller than 10% can be determined as the critical Q value. 10% is the standard Q value. If there is a foreign substance, the measured Q value is smaller than the reference Q value by at least the allowable error. The foreign substance detection step can be performed by measuring the amount of the foreign substance. The step of determining whether the Q value is equal to or greater than a critical Q value (S1512) may be included. If the measured Q value of the wireless power transmitter is equal to or greater than the critical Q value, no foreign matter is detected. In addition, the wireless power transmitter can determine that the measured Q value is equal to or greater than the critical value (S1513). If it is less than the Q value, it can be determined that a foreign substance has been detected (S1514).

[0296] In the wireless charging method for the wireless power transmitter, a foreign substance is detected in the first foreign substance detection step. If it is determined that there is no such signal, an ACK signal can be transmitted to the wireless power receiver (S1707). The wireless power transmitter wirelessly transmits an ACK packet in response to the FOD status packet. Power can be transmitted to a receiver.

[0297] In the wireless charging method in the wireless power transmitter, if an ACK is transmitted, the first guaranteed power value is included. The method may include transmitting the information to a wireless power transmitter (S1708). The power transmitter and the wireless power receiver enter into a power transmission contract based on the first guaranteed power value. As an example, the first guaranteed power value may be 5 W or more and 15 W or less.

[0298] When the wireless charging method in the wireless power transmitter transmits information including the first guaranteed power value, it can include a step (S1709) of shifting to the correction stage and performing correction. As an example, the correction execution can be that the wireless power transmitter predicts the power loss using the received power value of the wireless power receiver in the received power packet and the measured transmission power value. Also, the correction execution can be that the wireless power transmitter increases the intensity of the transmission power using the predicted power loss value.

[0299] The wireless charging method in the wireless power transmitter shifts to the power transmission stage after the correction execution and performs wireless charging with the first guaranteed power (which can include step S1710). In this case, performing wireless charging with the first guaranteed power can mean performing wireless charging according to the guaranteed power value in the power transmission contract concluded based on the first guaranteed power value.

[0300] If it is determined in S1706 that no foreign substance is detected, the wireless power transmitter can transmit a NAK to the wireless power receiver (S1711). That is, the wireless power transmitter can transmit a NAK packet to the wireless power receiver as a response to the reception of the FOD status packet.

[0301] When the wireless charging method in the wireless power transmitter transmits a NAK in S1711, it can include a step (S1712 - S1713) of determining whether to perform wireless charging. As an example, as shown in FIG. 15b, the determination of whether to perform wireless charging can include a step (S1 521) of determining the allowable Q value. More specifically, the wireless power transmitter uses the determined critical Q value The allowable Q value can be calculated using this. As an example, as shown in FIG. 7, the wireless power transmitter can determine the allowable Q value (Qp) as a value that has decreased by 0% or more and 20% or less at the critical Q value (Qth). More specifically, the wireless power transmitter can determine the value decreased by 20% at the critical Q value as the allowable Q value. The determination of whether to perform wireless charging includes the step (S1522) of determining whether the measured Q value is equal to or greater than the determined allowable Q value. The wireless power transmitter can determine to perform wireless charging if the measured Q value is equal to or greater than the allowable Q value (S1523). Also, the wireless power transmitter can determine not to perform wireless charging if the measured Q value is less than the allowable Q value (S1524). For example, as shown in FIG. 8, when the frequency of the transmission power is the first frequency, the measured Q value of the wireless power transmitter may be the first Q value (Q1), the second Q value (Q2), or the third Q value (Q3). When measured as the first Q value (Q1), since the probability that there is no foreign substance between the wireless power transmitter and the wireless power receiver is very high, it can be determined that there is no foreign substance. When measured as the third Q value (Q3), since the third Q value (Q3) is much lower than the critical Q value (Qth), the probability that there is a foreign substance between the wireless power transmitter and the wireless power receiver is very high, so it can be determined that there is a foreign substance. When measured as the second Q value (Q2), since the second Q value (Q2) is between the critical Q value (Qth) and the allowable Q value (Qp), there is a risk of misrecognizing that there is a foreign substance between the wireless power transmitter and the wireless power receiver. To prevent this, the wireless power transmitter can perform wireless charging if the measured Q value is equal to or greater than the allowable Q value. Hereafter, the wireless power transmitter When measured as the first Q value (Q1), since the probability that there is no foreign substance between the wireless power transmitter and the wireless power receiver is very high, it can be determined that there is no foreign substance. When measured as the third Q value (Q3), since the third Q value (Q3) is much lower than the critical Q value (Qth), the probability that there is a foreign substance between the wireless power transmitter and the wireless power receiver is very high, so it can be determined that there is a foreign substance. When measured as the second Q value (Q2), since the second Q value (Q2) is between the critical Q value (Qth) and the allowable Q value (Qp), there is a risk of misrecognizing that there is a foreign substance between the wireless power transmitter and the wireless power receiver. To prevent this, the wireless power transmitter can perform wireless charging if the measured Q value is equal to or greater than the allowable Q value. Hereafter, the wireless power transmitter When measured as the third Q value (Q3), since the third Q value (Q3) is much lower than the critical Q value (Qth), the probability that there is a foreign substance between the wireless power transmitter and the wireless power receiver is very high, so it can be determined that there is a foreign substance. When measured as the second Q value (Q2), since the second Q value (Q2) is between the critical Q value (Qth) and the allowable Q value (Qp), there is a risk of misrecognizing that there is a foreign substance between the wireless power transmitter and the wireless power receiver. To prevent this, the wireless power transmitter can perform wireless charging if the measured Q value is equal to or greater than the allowable Q value. Hereafter, the wireless power transmitter When measured as the second Q value (Q2), since the second Q value (Q2) is between the critical Q value (Qth) and the allowable Q value (Qp), there is a risk of misrecognizing that there is a foreign substance between the wireless power transmitter and the wireless power receiver. To prevent this, the wireless power transmitter can perform wireless charging if the measured Q value is equal to or greater than the allowable Q value. Hereafter, the wireless power ​The power transmitter can re-determine whether to stop wireless charging based on the internal temperature at S1718. Therefore, if the Q value is greater than or equal to the allowable Q value, the wireless power transmitter can decide to perform wireless charging. Thus, another embodiment can accurately detect foreign substances. Moreover, another embodiment can accurately detect foreign substances and prevent heat generation, a decrease in charging efficiency, and waste of power consumption. In addition, another embodiment can solve the problem that wireless charging is not performed due to a misrecognition of the presence of foreign substances in the past.

[0302] The wireless charging method in the wireless power transmitter can include a step (S1714) of stopping wireless charging when the wireless power transmitter decides not to perform wireless charging. More specifically, in this case, the wireless power transmitter can transition to the selection stage after a predetermined time has elapsed in the negotiation stage.

[0303] The wireless charging method in the wireless power transmitter can include a step (S1715) of transmitting information including a second guaranteed power value to the wireless power receiver when it is decided to perform wireless charging. In this case, the wireless power transmitter concludes a power transmission contract based on the wireless power receiver and the second guaranteed power value. As an example, the first guaranteed power value may be greater than the second guaranteed power value. In particular, the second guaranteed power value may be the minimum guaranteed power intensity of the wireless power transmitter. As another example, the second guaranteed power value may be 5W or less.

[0304] When the wireless charging method in the wireless power transmitter transmits information included as the second guaranteed power value, it proceeds to the power transmission stage without a correction stage and performs wireless charging with the second guaranteed power (S17 It can include (16). In this case, performing wireless charging with the second backup power means performing wireless charging according to the backup power value in the power transmission contract concluded based on the second backup power value. It can mean doing so.

[0305] The wireless charging method in the wireless power transmitter can include a step (S1717) of measuring the internal temperature inside the wireless power transmitter such as the charging area.

[0306] The wireless charging method in the wireless power transmitter can include a step (S1718) of determining whether the internal temperature is lower than a preset temperature during a preset period. The preset period and the preset temperature may be stored values.

[0307] The wireless charging method in the wireless power transmitter can include a step (S1719) of stopping wireless charging when the internal temperature becomes equal to or higher than a preset temperature during a preset period. More specifically, in this case, the wireless power transmitter can shift to a selection step after a predetermined time has elapsed in the power transmission step. That is, when the internal temperature of the wireless power transmitter becomes equal to or higher than a preset temperature during a preset period, it can be determined that a foreign substance is present and wireless charging can be stopped.

[0308] The wireless charging method in the wireless power transmitter can include a step (S1720) of performing a renegotiation step if the internal temperature is lower than a preset temperature during a preset period. As an example, the wireless power transmitter transmits a NAK packet to the wireless power receiver as a response to the received received power packet, and thereafter, the wireless power transmitter transmits a renegotiation packet to the wireless power receiver. It can be transmitted to the communication device to perform the renegotiation stage. That is, if the internal temperature is less than the preset temperature during the preset period, the wireless power transmitter determines that there is no foreign substance and can increase the transmission power intensity.

[0309] When the wireless charging method in the wireless power transmitter enters the renegotiation stage, it can include the step (S1721) of transmitting information including the third guaranteed power value to the wireless power receiver. In this case, the wireless power transmitter concludes a power transmission contract based on the wireless power receiver and the third guaranteed power value. As an example, the third guaranteed power value may be greater than the second guaranteed power value. As another example, the third guaranteed power value may be between 5W and 15W. Also, considering the NAK transmitted by Friendly metal, the third guaranteed power value may be less than or the same as the first guaranteed power value.

[0310] The wireless charging method in the wireless power transmitter can include the step (S1722) of shifting to the power transmission stage and performing wireless charging with the third guaranteed power. In this case, performing wireless charging with the third guaranteed power can mean performing wireless charging according to the guaranteed power value in the power transmission contract concluded based on the third guaranteed power value. Thereby, in the negotiation stage, the wireless power transmitter determines that a foreign substance is detected and reduces the transmission power intensity to protect the system, but finally, if it is determined that no foreign substance is detected in the power transmission stage, the transmission power intensity can be increased to increase the wireless charging efficiency.

[0311] When the reference Q value is not less than 50 in S1704 in the wireless charging method in the wireless power transmitter , may include the step of detecting a second foreign substance (S1723~S1724). As an example, As shown in Fig. 15a, the foreign substance detection step may include the step of determining a critical Q value (S1511). More specifically, the wireless power transmitter can calculate the critical Q value by using the received reference Q value. The wireless power transmitter can determine a value less than at least 10% of the reference Q value as the critical Q value at the reference Q value. 10% is the allowable error of the reference Q value. When there is a foreign substance, the measured Q value is at least less than the reference Q value by the allowable error, and the foreign substance can be detected by using this. In addition, the foreign substance detection step may include the step of determining whether the measured Q value is greater than or equal to the critical Q value (S1512). If the measured Q value is greater than or equal to the critical Q value, the wireless power transmitter can determine that no foreign substance has been detected (S1513). In addition, if the measured Q value is less than the critical Q value, the wireless power transmitter can determine that a foreign substance has been detected (S1514). If the wireless power transmitter determines that no foreign substance has been detected in the second foreign substance detection step, it can transition to S1707.

[0312]

[0313] If the wireless power transmitter determines that no foreign substance has been detected in S1724, it can transmit a NAK to the wireless power receiver (S1725). That is, the wireless power transmitter can transmit a NAK packet to the wireless power receiver as a response to receiving the FOD status packet.

[0314] If the wireless power transmitter transmits a NAK in S1725, the wireless charging It can include a stage (S1726) of stopping. That is, after the detection of the second foreign substance, without going through the stage of determining whether to perform wireless power charging, the wireless charging can be stopped. More specifically, in this case, the wireless power transmitter can transition to the selection stage after a predetermined time has elapsed during the negotiation stage. When the wireless power transmitter sends a NAK, the wireless charging can be stopped without going through the stage of determining whether to perform wireless charging. More specifically, in this case, the wireless power transmitter can transition to the selection stage after a predetermined time has elapsed during the negotiation stage.

[0315] FIG. 18 is a drawing for explaining a wireless charging method in a wireless power transmitter according to still another embodiment.

[0316] Referring to FIG. 18, the wireless charging method in the wireless power transmitter can include a stage (S1801) of sensing an object in the charging area. More specifically, the wireless power transmitter can sense an object based on the current change of the transmission coil by transmitting an analog ping. More specifically, the wireless power transmitter can sense an object based on the current change of the transmission coil by transmitting an analog ping.

[0317] The wireless charging method in the wireless power transmitter can include a stage (S1802) of measuring the Q value before the ping stage. As an example, the wireless power transmitter can measure the Q value using the sensing unit during the selection stage. As an example, the wireless power transmitter can measure the Q value using the sensing unit during the selection stage.

[0318] The wireless charging method in the wireless power transmitter can include a stage (S1803) of receiving information including a reference Q value. More specifically, the wireless power transmitter can receive a FOD status packet including the reference Q value. More specifically, the wireless power transmitter can receive a FOD status packet including the reference Q value.

[0319] The wireless charging method in the wireless power transmitter can include a stage (S1804 - S1805) of detecting a foreign substance using the measured Q value and the reference Q value. As an example, as shown in FIG. 15a, the foreign substance detection stage can include a stage (S1511) of determining a critical Q value. As an example, as shown in FIG. 15a, the foreign substance detection stage can include a stage (S1511) of determining a critical Q value. ​​​​​​Specifically, the wireless power transmitter can calculate a critical Q value using the received reference Q value. The wireless power transmitter can determine a value less than at least 10% as the critical Q value at the reference Q value. 10% is the allowable error of the reference Q value. When there is a foreign substance, it is possible to detect the foreign substance by utilizing the fact that the measured Q value is at least less than the reference Q value by the allowable error. The foreign substance detection stage can include a stage (S1512) of determining whether the measured Q value is above the critical Q value. If the measured Q value of the wireless power transmitter is above the critical Q value, it can be determined that no foreign substance is detected (S1513). Also, if the measured Q value of the wireless power transmitter is less than the critical Q value, it can be determined that a foreign substance is detected (S1514). The wireless power transmitter can determine that no foreign substance is detected if the measured Q value is above the critical Q value. If the measured Q value is less than the critical Q value, the wireless power transmitter can determine that a foreign substance is detected. (S1514).

[0320] When it is determined that no foreign substance is detected in the wireless charging method of the wireless power transmitter, it can include a stage (S1807) of transmitting information including a first guaranteed power value to the wireless power transmitter. In this case, the wireless power transmitter concludes a power transmission contract based on the wireless power receiver and the first guaranteed power value. As an example, the first guaranteed power value may be greater than 5W. Thereafter, the wireless power transmitter can shift to the power transmission stage and perform wireless charging with the first guaranteed power. In this case, performing wireless charging with the first guaranteed power can mean performing wireless charging according to the guaranteed power value in the power transmission contract concluded based on the first guaranteed power value.

[0321] When it is determined in S1805 that a foreign substance is detected in the wireless charging method of the wireless power transmitter, it can include a stage (S1807) of transmitting information including a second guaranteed power value to the wireless power receiver. ​ This can be achieved. In this case, the wireless power transmitter can, based on the wireless power receiver and the second guaranteed power value, conclude a power transmission contract. As an example, the first guaranteed power value may be greater than the second guaranteed power value. In particular, the second guaranteed power value may be the minimum guaranteed power intensity of the wireless power transmitter. As another example, the second guaranteed power value may be 5 W or less. Thereafter, the wireless power transmitter can transition to the power transmission stage without a correction stage and perform wireless charging with the second guaranteed power. In this case, performing wireless charging with the second guaranteed power can mean performing wireless charging according to the guaranteed power value in the power transmission contract concluded based on the second guaranteed power value. Also, after a certain period of time, if the receiver determines that there is no foreign substance, it can increase the guaranteed power through renegotiation.

[0322] FIG. 19 is a diagram for explaining a wireless charging method in a wireless charging system according to still another embodiment.

[0323] Referring to FIG. 19, the wireless power transmitter 1910 can transmit an analog ping to the wireless power receiver 1920 in the selection stage (S1901).

[0324] The wireless power transmitter 1910 can measure the Q value before the ping stage (S190 2). As an example, the wireless power transmitter 1910 can measure the Q value in the selection stage.

[0325] When an object is detected, the wireless power transmitter 1910 can transition from the selection stage to the ping stage. The wireless power transmitter 1910 can activate the wireless power receiver 1920 and transmit a digital ping to identify whether the receiver is the wireless power receiver 1920. ​​​​​​​​ it can be done (S1903). The wireless power receiver 1920, as a response to the digital ping, can transmit a signal strength packet (S1904).

[0326] When the ping stage is completed, in the identification and configuration stages, the wireless power receiver 1920 can transmit an identification packet for notifying identification information and a configuration packet for notifying configuration information. That is, it can be done (S1905 - S1906). The wireless power transmitter 1910 and the wireless power receiver 192 0 can transition to the negotiation stage if the negotiation field value of the configuration packet is a value that instructs to execute the negotiation stage.

[0327] In the negotiation stage, the wireless power receiver 1920 can transmit an FOD status packet to detect FO (S1907). The FOD status packet can include a reference Q value.

[0328] The wireless power transmitter 1910 can perform foreign object detection (S1908). The foreign object detection can detect foreign objects by using the measured Q value and the information of the received FOD status packet. Refer to the description of the wi...

Claims

1. In a wireless charging method for a wireless power receiver, transmitting a FOD (Foreign Object Detection) status packet to a wireless power transmitter; receiving a response signal corresponding to the FOD status packet from the wireless power transmitter; when the response signal is an ACK signal indicating that no foreign substance is detected, transmitting a request signal for a first guaranteed power value to the wireless power transmitter; when the response signal is a NAK signal indicating that a foreign substance is detected, transmitting a request signal for a second guaranteed power value to the wireless power transmitter, wherein the first guaranteed power value is greater than the second guaranteed power value, the wireless charging method.

2. The FOD status packet includes a reference Q (Quality Factor Value) value, wherein the reference Q (Quality Factor Value) value is a Q (Quality Factor Value) value measured by a reference coil unit included in the wireless power receiver. The wireless charging method according to claim 1.

3. Further comprising receiving wireless power determined based on the request signal for the first guaranteed power value or the request signal for the second guaranteed power value transmitted from the wireless power transmitter. The wireless charging method according to claim 1.

4. The first guaranteed power value is the maximum transmission power value of the wireless power transmitter. The wireless charging method according to claim 3.

5. When the response signal is a NAK signal, further comprising shifting to a renegotiation stage and transmitting a request signal for a third guaranteed power value to the wireless power transmitter, wherein the third guaranteed power value is smaller than the first guaranteed power value and larger than the second guaranteed power value. The wireless charging method according to claim 1.

6. The request signal for the third guaranteed power value is transmitted based on an internal temperature of at least one of the wireless power transmitter and the wireless power receiver. The wireless charging method according to claim 5.

7. The second guaranteed power value is the minimum guaranteed power of the wireless power transmitter. The wireless charging method according to claim 1.

8. The step of receiving the wireless power when transmitting the request signal for the first guaranteed power value, shifts to a power transmission stage after performing a correction stage, when transmitting the request signal for the second guaranteed power value, shifts to a power transmission stage without performing a correction stage. The wireless charging method according to claim 3.

9. The wireless charging method according to claim 8, wherein the correcting step includes transmitting received power information to the wireless power transmitter to determine lost power.

10. The wireless charging method according to claim 9, further comprising transmitting a control error signal to the wireless power transmitter to adjust the intensity of the received wireless power.

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