FOREIGN OBJECT DETECTION APPARATUS AND METHOD, AND WIRELESS CHARGING TRANSMITTER DEVICE

Abstract

The embodiments of the present application provide a foreign object detection device and a foreign object detection method. The foreign object detection device includes a controller, a first resonant network, a signal coupler, and a phase difference detector. The signal coupler may obtain a resonant current signal corresponding to the first resonant network, and couple the resonant current signal to a preset carrier signal to obtain a combined current signal. In this specification, the frequency of the preset carrier signal is the same as the frequency of the excitation signal. The phase difference detector may extract a low-frequency signal component from the combined current signal, and determine a phase difference signal based on the low-frequency signal component. The amplitude of the phase difference signal correspondingly indicates a phase difference between the excitation signal and the resonant current signal. The controller may determine whether a foreign object exists in the detection area corresponding to the first resonant network based on the amplitude of the phase difference signal. By using the device and method provided in the embodiments of the present application, the cost of foreign object detection can be reduced and the accuracy of foreign object detection can be improved.

Description

[Technical field]

[0001] The present application relates to the field of wireless charging, and in particular to a foreign object detection apparatus and method, and a wireless charging transmitting end device. [Background technology]

[0002] With the continuous development of wireless charging technology, magnetic coupling wireless energy transmission technology has become the trendy research direction of wireless charging technology. Because magnetic coupling wireless energy transmission technology makes it easier to implement long-distance high-power energy transmission. A magnetic coupling wireless charging system usually includes two separate devices, a wireless charging transmitting end device and a wireless charging receiving end device. The wireless charging transmitting end device includes a power transmitting device, and the wireless charging receiving end device includes a power receiving device. The power transmitting device is connected to a power source, and the power receiving device is connected to a device to be charged (such as an electric vehicle or a mobile phone). The power transmitting device and the power receiving device transfer energy through electromagnetic induction between a transmitting coil and a receiving coil to implement wireless charging. There is a certain space gap between the power transmitting device and the power receiving device. Therefore, when a foreign object (especially a metal foreign object), such as a coin or tin foil, exists in the space gap during charging of the device to be charged, the foreign object will cause a vortex effect under the action of a high-frequency electromagnetic field. As a result, the temperature of the foreign object will rise rapidly, which may cause a fire or other hazard. Therefore, when the magnetically coupled wireless charging system charges the target device, foreign object detection needs to be performed to ensure the safety of the wireless charging system and the target device.

[0003] In the prior art, whether a foreign object exists is usually determined based on a change in an electrical parameter caused by a change in the physical characteristics of one or more foreign object detection coils disposed between the power transmitting device and the power receiving device. For example, the value of the current or voltage of the foreign object detection coil is detected by using an analog circuit, and whether a foreign object exists in the space gap is directly determined based on the current or voltage of the foreign object detection coil. In another example, the current or voltage parameter detected by the analog circuit may alternatively be sent to a controller, which processes the current or voltage parameter to obtain a corresponding phase angle or frequency parameter, and then determines whether a foreign object exists in the space gap based on the phase angle or frequency parameter. However, the conventional foreign object detection solution usually has the problem of low detection accuracy or high system complexity. As a result, the reliability and applicability of the conventional foreign object detection solution are low. Therefore, there is an urgent need to propose a foreign object detection solution that is easy to implement and has high detection accuracy. Summary of the Invention

[0004] To solve the above problems, the present application provides a foreign object detection apparatus and method, and a wireless charging transmitting end device. The foreign object detection apparatus and method provided in the present application can easily and accurately perform foreign object detection, reduce the cost of foreign object detection, and improve the accuracy of foreign object detection.

[0005] According to a first aspect, an embodiment of the present application provides a foreign object detection device. The foreign object detection device includes a controller, a first resonant network, a signal coupler, and a phase difference detector. The signal coupler may be configured to obtain a resonant current signal corresponding to the first resonant network when the first resonant network is operating normally under the action of an excitation signal, couple a preset carrier signal to the resonant current signal to obtain a combined current signal, and transmit the combined current signal to the phase difference detector. In this specification, the frequency of the preset carrier signal is the same as the frequency of the excitation signal. The phase difference detector may be configured to extract a low-frequency signal component from the combined current signal, determine a phase difference signal based on the low-frequency signal component, and transmit the phase difference signal to the controller. In this specification, the low-frequency signal component is a signal component having a frequency less than or equal to a first preset frequency in the combined current signal, and the amplitude of the phase difference signal correspondingly indicates a phase difference between the excitation signal and the resonant current signal. The controller may be configured to determine whether a foreign object is present in a detection area corresponding to the first resonant network based on the amplitude of the phase difference signal.

[0006] In the above implementation, the foreign object detection device may use a signal coupler and a phase difference detector to directly detect a phase difference signal that may indicate a phase difference between the excitation signal of the first resonant network and a resonant current signal corresponding to the excitation signal of the first resonant network, and use a controller to perform simple processing on the phase difference signal to determine whether a foreign object is present in the detection area corresponding to the first resonant network. The foreign object detection device provided in the present application may use a signal coupler and a phase difference detector to directly detect a phase difference signal that may indicate a phase difference between the excitation signal and the resonant current signal, and then perform simple processing on the phase difference signal to implement foreign object detection. This reduces the overall system complexity and cost compared to the conventional scheme in which the controller processes the current or voltage parameters detected by an analog circuit to obtain a phase angle or frequency parameter, and then performs foreign object detection based on the phase angle or frequency parameter. In addition, the foreign object detection device provided in the present application may use a phase difference signal to determine whether a foreign object is present. In this way, the problem of low detection accuracy due to interference from the primary power on the current or voltage parameters can be avoided in a manner where foreign object detection is directly performed based on the measured current or voltage parameters. Therefore, the foreign object detection device provided in this application can reduce the cost of foreign object detection and improve the accuracy and reliability of foreign object detection.

[0007] In relation to the first aspect, in a possible implementation, the foreign object detection device further includes a current detector, which may be configured to detect a current output by the first resonant network to obtain a resonant current signal when the first resonant network is operating normally under the action of the excitation signal, and transmit the resonant current signal to the signal coupler.

[0008] In relation to the first aspect, in a possible implementation, the signal combiner includes a first inverter and a signal selector. The first inverter is configured to perform a phase shift on the resonant current signal to obtain an anti-resonant current signal. In this specification, the phase difference between the anti-resonant current signal and the resonant current signal is 180 degrees. The signal selector may be configured to select the resonant current signal or the anti-resonant current signal as the output combined current signal based on a preset carrier signal.

[0009] In the above implementation, the combined current signal is obtained through combination by a first inverter and a signal selector, which has a simple structure and is widely used, thereby reducing the cost of the foreign object detection device, simplifying the structure of the foreign object detection device, and improving the stability and robustness of the foreign object detection device.

[0010] In relation to the first aspect, in a possible implementation, the signal selector includes a first switching transistor, a second switching transistor, and a second inverter. The preset carrier signal is input to a first end of the first switching transistor through the second inverter. The preset carrier signal is also input to a first end of the second switching transistor. The resonant current signal is input to a second end of the first switching transistor. The anti-resonant current signal is input to a second end of the second switching transistor. The third end of the first switching transistor is connected to the third end of the second switching transistor and serves as an output end of the signal selector. The preset carrier signal may control the first switching transistor to be turned on through the second inverter and control the second switching transistor to be turned off, so that the resonant current signal is output as a combined current signal. Alternatively, the preset carrier signal may control the second switching transistor to be turned on and the first switching transistor to be turned off, so that the anti-resonant current signal is output as the combined current signal.

[0011] In the above implementation, the signal selector is implemented by using switching transistors and inverters, which have a stable structure and are cost-effective, which can facilitate the integration of the signal selector and further reduce the implementation cost of the foreign object detection device.

[0012] In relation to the first aspect, in a possible implementation, the excitation signal is a sine signal, the preset carrier signal is a square wave signal, and the phase difference between the excitation signal and the preset carrier signal is 90 degrees.

[0013] In relation to the first aspect, in a possible implementation, the signal combiner includes a multiplier or an analog multiplication circuit configured to multiply the preset carrier signal by the resonant current signal to obtain a combined current signal.

[0014] In the above implementation, a multiplier or an analog multiplication circuit is used to perform signal combining on the preset carrier signal and the resonant current signal. This method is simple and easy to implement, and can improve the efficiency of foreign object detection.

[0015] In relation to the first aspect, in a possible implementation, the excitation signal and the preset carrier signal are sinusoidal signals.

[0016] In relation to the first aspect, in a possible implementation, the controller may determine an amplitude of the phase difference signal. If the controller determines that the amplitude of the phase difference signal is greater than or equal to a first preset amplitude or less than or equal to a second preset amplitude, the controller determines that a foreign object is present in the detection area corresponding to the first resonant network, and the first preset amplitude is greater than the second preset amplitude. If the controller determines that the amplitude of the phase difference signal is less than the first preset amplitude and greater than the second preset amplitude, the controller determines that a foreign object is not present in the detection area corresponding to the first resonant network.

[0017] In the above implementation, foreign object detection is performed directly through the amplitude of the phase difference signal and the comparison between the values ​​of the first preset amplitude and the second preset amplitude. This method is simple and easy to implement, can reduce the requirements for the data processing capability of the controller, and can reduce the cost of foreign object detection.

[0018] In relation to the first aspect, in a possible implementation, the foreign object detection device further includes an amplitude detector. The amplitude detector may be configured to detect a target signal amplitude of the resonant current signal. The controller may be configured to determine whether a foreign object is present in the detection area corresponding to the first resonant network based on the target signal amplitude and the amplitude of the phase difference signal.

[0019] In relation to the first aspect, in a possible implementation, the controller may be configured to determine an amplitude of the phase difference signal; may be configured to determine that a foreign object is present in the detection area corresponding to the first resonant network if it is determined that the quotient of the amplitude of the phase difference signal and the target signal amplitude is greater than or equal to a first preset threshold, or less than or equal to a second preset threshold; or may be configured to determine that a foreign object is not present in the detection area corresponding to the first resonant network if it is determined that the quotient of the amplitude of the phase difference signal and the target signal amplitude is greater than the second preset threshold and less than the first preset threshold.

[0020] In the above implementation, the quotient of the amplitude of the phase difference signal and the target signal amplitude is related only to the phase difference between the excitation signal and the resonant current signal. Therefore, the controller determines whether a foreign object exists in the detection area based on the quotient of the amplitude of the phase difference signal and the target signal amplitude. This can avoid the case where the amplitude of the resonant current signal changes, and the detection accuracy of the foreign object detection device can be improved.

[0021] In relation to the first aspect, in a possible implementation, the controller may be configured to determine an amplitude of the phase difference signal; and may be configured to determine that a foreign object is present in the detection area corresponding to the first resonant network if it is determined that the target signal amplitude is greater than or equal to the third preset amplitude and the quotient of the amplitude of the phase difference signal and the target signal amplitude is greater than or equal to the first preset threshold or less than or equal to the second preset threshold; or may be configured to determine that a foreign object is not present in the detection area corresponding to the first resonant network if it is determined that the target signal amplitude is less than the third preset amplitude or if it is determined that the quotient of the amplitude of the phase difference signal and the target signal amplitude is greater than the second preset threshold and less than the first preset threshold.

[0022] In the above implementation, the value of the amplitude of the phase difference signal is further related to a target signal amplitude of the resonant current signal, and the value of the target signal amplitude is further related to a size of an object in the detection area (the object may be a foreign object or may be a non-foreign object, e.g., a structure such as a body or chassis of an electric vehicle). Therefore, in the above implementation, the judgment is performed based on both the value of the target signal amplitude and the value of the quotient. This can avoid cases where a non-foreign object structure (e.g., a structure such as a body or chassis of an electric vehicle) is recognized as a foreign object, and can improve the detection accuracy of the foreign object detection device.

[0023] In relation to the first aspect, in a possible implementation, the foreign object detection device may further include a signal generator, and the signal generator may be configured to generate the preset carrier signal and the excitation signal according to a signal control command sent by the controller. In this specification, the frequency of the preset carrier signal and the excitation signal is indicated by the signal control command.

[0024] In relation to the first aspect, in a possible implementation, the foreign object detection device further includes a second resonant network and a switching module, and the second resonant network and the first resonant network are separately connected to the switching module. The switching module may be configured to determine whether the excitation signal generated by the signal generator is sent to the first resonant network or the second resonant network based on a resonant network selection signal coming from the controller.

[0025] According to a second aspect, an embodiment of the present application provides a foreign object detection method. The foreign object detection method is applied to a foreign object detection device, which includes a first resonant network, a signal coupler, a phase difference detector, and a controller. The method includes a step in which the signal coupler couples a resonant current signal corresponding to the first resonant network to a preset carrier signal when the first resonant network is operating normally under the action of an excitation signal to obtain a combined current signal. The phase difference detector extracts a low-frequency signal component from the combined current signal and determines a phase difference signal based on the low-frequency signal component, the low-frequency signal component being a signal component having a frequency less than or equal to a preset frequency in the modulated current signal, and the signal amplitude of the phase difference signal indicates a phase difference between the excitation signal and the resonant current signal. The controller determines whether a foreign object is present in a detection area corresponding to the first resonant network based on the phase difference signal.

[0026] In relation to the second aspect, in a possible implementation, the foreign object detection device further includes a current detector, the method further including the step of the current detector detecting a current output by the first resonant network to obtain a resonant current signal when the first resonant network is operating normally under the action of the excitation signal.

[0027] In relation to the second aspect, in a possible implementation, the signal combiner includes a first inverter and a signal selector. The first inverter performs a phase shift on the resonant current signal to obtain an anti-resonant current signal, and a phase difference between the anti-resonant current signal and the resonant current signal is 180 degrees. The signal selector selects the resonant current signal or the anti-resonant current signal as the output combined current signal based on a preset carrier signal.

[0028] In relation to the second aspect, in a possible implementation, the signal selector includes a first switching transistor, a second switching transistor, and a second inverter. The preset carrier signal is input to a first end of the first switching transistor through the second inverter. The preset carrier signal is also input to a first end of the second switching transistor. The resonant current signal is input to a second end of the first switching transistor. The anti-resonant current signal is input to a second end of the second switching transistor. The third end of the first switching transistor is connected to the third end of the second switching transistor and serves as an output end of the signal selector. The preset carrier signal input to the first end of the first switching transistor and flowing through the second inverter controls the first switching transistor to be turned on, and the preset carrier signal input to the first end of the second switching transistor controls the second switching transistor to be turned off, so that the resonant current signal is output as a combined current signal. Alternatively, the second switching transistor is controlled to be turned on by a preset carrier signal input to a first end of the second switching transistor, and the first switching transistor is controlled to be turned off by a preset carrier signal input to a first end of the first switching transistor and flowing through a second inverter, so that the anti-resonant current signal is output as a combined current signal.

[0029] In relation to the second aspect, in a possible implementation, the excitation signal is a sine signal, the preset carrier signal is a square wave signal, and the phase difference between the excitation signal and the preset carrier signal is 90 degrees.

[0030] In relation to the second aspect, in a possible implementation, the signal combiner includes a multiplier or an analog multiplication circuit, which multiplies the preset carrier signal by the resonant current signal to obtain a combined current signal.

[0031] In relation to the second aspect, in a possible implementation, the excitation signal and the preset carrier signal are sinusoidal signals.

[0032] In relation to the second aspect, in a possible implementation, the controller may determine an amplitude of the phase difference signal. If the controller determines that the amplitude of the phase difference signal is greater than or equal to a first preset amplitude or less than or equal to a second preset amplitude, the controller determines that a foreign object is present in the detection area corresponding to the first resonant network, and the first preset amplitude is greater than the second preset amplitude. If the controller determines that the amplitude of the phase difference signal is less than the first preset amplitude and greater than the second preset amplitude, the controller determines that a foreign object is not present in the detection area corresponding to the first resonant network.

[0033] In relation to the second aspect, in a possible implementation, the foreign object detection device further includes an amplitude detector, which may detect a target signal amplitude of the resonant current signal.

[0034] In relation to the second aspect, in a possible implementation, the controller may determine an amplitude of the phase difference signal. If the controller determines that the quotient of the amplitude of the phase difference signal and the target signal amplitude is greater than or equal to a first preset threshold or less than or equal to a second preset threshold, the controller determines that a foreign object is present in the detection area corresponding to the first resonant network. If the controller determines that the quotient of the amplitude of the phase difference signal and the target signal amplitude is greater than the second preset threshold and less than the first preset threshold, the controller determines that a foreign object is not present in the detection area corresponding to the first resonant network.

[0035] In relation to the second aspect, in a possible implementation, the controller may determine the amplitude of the phase difference signal. If the controller determines that the target signal amplitude is greater than or equal to the third preset amplitude, and the quotient of the amplitude of the phase difference signal and the target signal amplitude is greater than or equal to the first preset threshold, or less than or equal to the second preset threshold, the controller determines that a foreign object is present in the detection area corresponding to the first resonant network. If the controller determines that the target signal amplitude is less than the third preset amplitude, or the quotient of the amplitude of the phase difference signal and the target signal amplitude is greater than the second preset threshold and less than the first preset threshold, the controller determines that a foreign object is not present in the detection area corresponding to the first resonant network.

[0036] In relation to the second aspect, in a possible implementation, the foreign object detection device further includes a signal generator. The controller may generate a signal control command and transmit the signal control command to the signal generator. The signal generator may generate a preset carrier signal and an excitation signal according to the signal control command. In this specification, the frequency of the preset carrier signal and the excitation signal is indicated by the signal control command.

[0037] In relation to the second aspect, in a possible implementation, the foreign object detection device further includes a second resonant network and a switching module. The second resonant network and the first resonant network are separately connected to the switching module. The controller may generate a resonant network selection signal and send the resonant network selection signal to the switching module. The switching module may determine whether the excitation signal generated by the signal generator is sent to the first resonant network or the second resonant network based on the resonant network selection signal.

[0038] According to a third aspect, an embodiment of the present application provides a wireless charging transmitting end device. The wireless charging transmitting end device includes a power transmitting device and a foreign object detection device provided in the first aspect. In this specification, the foreign object detection device can be disposed on the side of the power transmitting device facing the wireless charging power receiving device. The power receiving device is included in the wireless charging receiving end device corresponding to the wireless charging transmitting end device. It should be noted that in a specific implementation, the power transmitting device can include a power transmitting coil, the power receiving device can include a power receiving coil, and the foreign object detection device can be disposed on the side of the power transmitting coil facing the power receiving coil.

[0039] According to a fourth aspect, an embodiment of the present application provides a wireless charging receiving end device. The wireless charging receiving end device includes a power receiving device and a foreign object detection device provided in the first aspect. In this specification, the foreign object detection device can be disposed on the side of the power receiving device facing the wireless charging power transmitting device. The power transmitting device can be included in the wireless charging transmitting end device corresponding to the wireless charging receiving end device. It should be noted that in a specific implementation, the power transmitting device can include a power transmitting coil, the power receiving device can include a power receiving coil, and the foreign object detection device can be disposed on the side of the power receiving coil facing the power transmitting coil. [Brief description of the drawings]

[0040] [Figure 1] FIG. 1 is a schematic diagram of the structure of a wireless charging system according to an embodiment of the present application.

[0041] [Diagram 2] FIG. 2 is a schematic diagram of another structure of a wireless charging system according to an embodiment of the present application.

[0042] [Diagram 3] 1 is a schematic diagram of the structure of a foreign object detection device according to an embodiment of the present application;

[0043] [Figure 4] FIG. 2 is a schematic diagram of another structure of a foreign object detection device according to an embodiment of the present application.

[0044] [Diagram 5] FIG. 2 is a schematic diagram of another structure of a foreign object detection device according to an embodiment of the present application.

[0045] [Figure 6] FIG. 2 is a schematic diagram of waveform changes according to an embodiment of the present application.

[0046] [Figure 7] FIG. 2 is a schematic diagram of signal coupling according to an embodiment of the present application;

[0047] [Figure 8] FIG. 2 is another schematic diagram of signal coupling according to an embodiment of the present application;

[0048] [Figure 9] FIG. 2 is a schematic diagram of another structure of a foreign object detection device according to an embodiment of the present application.

[0049] [Figure 10] FIG. 2 is a schematic diagram of a signal combiner structure according to an embodiment of the present application;

[0050] [Figure 11] FIG. 2 is a schematic diagram of another structure of a foreign object detection device according to an embodiment of the present application.

[0051] [Figure 12] FIG. 2 is a schematic diagram of another structure of a foreign object detection device according to an embodiment of the present application.

[0052] [Figure 13] FIG. 2 is a schematic diagram of another structure of a foreign object detection device according to an embodiment of the present application.

[0053] [Figure 14] FIG. 2 is a schematic diagram of another structure of a foreign object detection device according to an embodiment of the present application.

[0054] [Figure 15]FIG. 2 is a schematic diagram of another structure of a foreign object detection device according to an embodiment of the present application.

[0055] [Figure 16] 1 is a schematic flow chart of a foreign object detection method according to an embodiment of the present application;

[0056] [Figure 17] FIG. 2 is a schematic diagram of the structure of another wireless charging system according to an embodiment of the present application.

[0057] [Figure 18] FIG. 2 is a schematic diagram of the structure of another wireless charging system according to an embodiment of the present application. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0058] The following clearly describes the technical solutions in the embodiments of the present application with reference to several accompanying drawings provided in the embodiments of the present application.

[0059] The foreign object detection device and the foreign object detection method provided in the present application are applicable to an electromagnetically coupled wireless charging system. The electromagnetically coupled wireless charging system may be a wireless charging system used in an electric vehicle, or may be a wireless charging system used in a mobile device, such as a tablet computer or a mobile phone, or may be a wireless charging system used in a smart robot or an electric pallet truck, etc. This may be determined based on an actual application scenario and is not limited in the present application. For ease of explanation, the present application uses a wireless charging system used in an electric vehicle as an example to explain the foreign object detection device and the foreign object detection method based on the foreign object detection device provided in the present application.

[0060] With the worsening of energy shortage and environmental pollution in modern society, electric vehicles as new energy vehicles have attracted widespread attention since their launch. An electric vehicle is a vehicle that is powered by an on-board power source, meets various requirements of road traffic and safety regulations, and uses a motor to drive vehicle wheels to move. Battery charging methods for electric vehicles usually include contact charging and wireless charging. Contact charging means that the metal of the plug is in contact with the metal of the socket to conduct electricity, and wireless charging means that the coupled electromagnetic field serves as a medium to transmit electric energy. Compared with contact charging, wireless charging has the advantages of easy use, no risk of spark or electric shock, no mechanical wear, adaptable to various harsh environmental and weather conditions, and easy implementation of automatic charging and mobile charging, and may become the mainstream charging mode for electric vehicles in the future. In the following, a wireless charging system used in an electric vehicle is used as an example to describe an example of the architecture of a wireless charging system to which the foreign object detection device provided in the present application is applicable.

[0061] 1 is a schematic diagram of the structure of a wireless charging system according to an embodiment of the present application. As shown in FIG. 1, the wireless charging system may include at least an electric vehicle 100 and a wireless charging station 101. The electric vehicle 100 may be provided with a wireless charging receiving device 1000, and the wireless charging station 101 may be provided with a wireless charging transmitting device 1010. At present, the process of charging an electric vehicle by the wireless charging system is jointly completed by the wireless charging receiving device 1000 and the wireless charging transmitting device 1010. In this specification, the wireless charging receiving device 1000 is a power receiving device in the wireless charging system, and the wireless charging transmitting device 1010 is a power transmitting device in the wireless charging system.

[0062] In some possible implementations, the wireless charging station 101 may be a stationary wireless charging station, a stationary wireless charging parking space, or a wireless charging road, etc. This is not limited in the present application. The wireless charging receiving device 1000 may be integrated at the bottom of the electric vehicle 100. When the electric vehicle 100 enters the wireless charging range of the wireless charging transmitting device 1010, the electric vehicle 100 may be charged through wireless charging. The wireless charging receiving device 1000 may include components such as a power receiving coil and a rectifier circuit. The power receiving coil and the rectifier circuit may be integrated or separated. When the power receiving coil and the rectifier circuit are separated, the rectifier circuit is usually placed in the vehicle. FIG. 1 shows a case where the power receiving coil and the rectifier circuit are integrated. The wireless charging transmitting device 1010 may include a power transmitting coil and an inverter circuit. The power transmitting coil and the inverter circuit may also be integrated or separated. FIG. 1 shows a case where the power transmitting coil and the inverter circuit are integrated.

[0063] In some possible implementations, the contactless charging may be that the wireless charging receiving device 1000 and the wireless charging transmitting device 1010 wirelessly transmit energy through magnetic field coupling, which may be electromagnetic induction or magnetic resonance, etc. This is not limited in the present application. In practical applications, the electric vehicle 100 and the wireless charging station 101 may alternatively perform bidirectional charging. Specifically, the wireless charging station 101 may charge the electric vehicle 100, and the electric vehicle 100 may also charge the wireless charging station in reverse.

[0064] With reference to Fig. 2, the following describes an exemplary structure of the wireless charging transmitting device 1010 and the wireless charging receiving device 1000 in the wireless charging system shown in Fig. 1. Fig. 2 is a schematic diagram of another structure of the wireless charging system according to an embodiment of the present application. As shown in Fig. 2, the wireless charging system includes the wireless charging receiving device 1000 and the wireless charging transmitting device 1010 shown in Fig. 1.

[0065] In a specific implementation, the wireless charging transmitting device 1010 may include a transmitting conversion module 1011, a power transmitting module 1012, a transmitting control module 1013 connected to the transmitting conversion module 1011 and the power transmitting module 1012, a transmitting communication module 1014 connected to the transmitting control module 1013, an authentication management module 1015 connected to the transmitting communication module 1014, and a storage module 1016 connected to the authentication management module 1015, etc. In this specification, it may be understood that the power transmitting module 1012 may be a power transmitting coil (or referred to as a transmitting coil).

[0066] Optionally, the transmission conversion module 1011 may be connected to the power supply of the wireless charging transmitting device 1010, and is configured to convert the AC or DC output by the power supply into high-frequency AC. In this specification, when the current output by the power supply is AC, the transmission conversion module 1011 includes a power factor correction unit, an inverter unit (or referred to as an inverter circuit) and a transmission end compensation network; or when the current output by the power supply is DC, the transmission conversion module 1011 may include an inverter unit and a transmission end compensation network. In practical use, the power factor correction unit can ensure that the input current phase of the wireless charging system is consistent with the voltage phase of the power grid, so as to reduce the harmonic content of the system and increase the power factor value, so as to reduce the pollution caused by the wireless charging system to the power grid and improve reliability. The power factor correction unit may further be configured to increase or decrease the output voltage of the power factor correction unit according to the requirements of the next stage circuit in a practical application scenario. Optionally, if the variable range of the output voltage of the power factor correction unit does not meet the requirements of the actual application scenario, a DC conversion unit may be further added to the transmission conversion module 1011, and the DC conversion unit may be configured to adjust the voltage output to the next stage circuit, so that the variable range of the voltage output to the next stage circuit meets the requirements of the actual application scenario. The inverter unit may convert the output voltage of the power factor correction unit into a high-frequency AC voltage, and apply the high-frequency AC voltage to the power transmission module through the transmission end compensation network. The high-frequency AC voltage may greatly improve the transmission efficiency and transmission distance of the power transmission module. It should be noted that in this specification, the power source of the wireless charging transmission device 1010 may be a power source disposed in the wireless charging transmission device 1010, or may be an external power source connected to the wireless charging transmission device 1010. This is not limited in this application.

[0067] The power transmission module 1012 may be configured to transmit the high frequency alternating current provided by the transmission conversion module 1011 through a magnetic field.

[0068] The transmission control module 1013 can be configured to control the voltage, current and frequency conversion parameters of the transmission conversion module 1011, and control the voltage and current of the high-frequency AC in the power transmission module 1012, etc. according to the transmission power requirements of wireless charging in an actual application scenario.

[0069] The transmission communication module 1014 may be configured to perform wireless communication between the wireless charging transmitting device 1010 and the wireless charging receiving device 1000, including communication transmission of information such as power control information, fault protection information, on / off information, and interactive authentication information. The wireless charging transmitting device 1010 may receive electric vehicle attribute information, charging request, and interactive authentication information transmitted by the wireless charging receiving device 1000. In addition, the wireless charging transmitting device 1010 may further transmit wireless charging transmission control information, interactive authentication information, and past wireless charging data information, etc., to the wireless charging receiving device 1000. The mode of wireless communication may include, but is not limited to, any one or combination of Bluetooth® (Bluetooth®), Wireless Fidelity (Wi-Fi®), ZigBee® (ZigBee®) protocols, Radio Frequency Identification (RFID) technology, Long Range (Lora) wireless technology, and Near Field Communication (NFC) technology. Optionally, the transmission communication module 1014 may further communicate with an intelligent terminal of a user who owns an electric vehicle, and the user implements remote authentication and user information transmission through the communication function.

[0070] The authentication management module 1015 may be configured to perform interactive authentication and authorization management between the wireless charging transmitter 1010 and the electric vehicle in the wireless charging system.

[0071] The storage module 1016 may be configured to store charging process data, interactive authentication data (e.g., interactive authentication information) and permission management data (e.g., permission management information) of the wireless charging transmitting device 1010. The interactive authentication data and permission management data may be set at the factory or set by a user. This may be determined based on an actual application scenario and is not limited in this specification.

[0072] In a specific implementation, the wireless charging receiving device 1000 may include a power receiving module 1001, a receiving conversion module 1002, a receiving control module 1003 connected to the power receiving module 1001 and the receiving conversion module 1002, and a receiving communication module 1004 connected to the receiving control module 1003. It may be understood that the power receiving module 1001 in this specification may be a power receiving coil (or referred to as a receiving coil). Optionally, the receiving conversion module 1002 may be connected to an energy storage module 1005 of the wireless charging receiving device 1000 and transmits the received energy to the energy storage module 1005. The energy storage module 1005 may be connected to an energy storage management module 1006, which may be connected to a vehicle drive device of the electric vehicle and configured to drive the electric vehicle. It should be noted that in this specification, the energy storage management module 1006 and the energy storage module 1005 may be located within the wireless charging receiving device 1000 or may be located outside the wireless charging receiving device 1000. This is not limited in this application.

[0073] The power receiving module 1001 may be configured to receive the active power and reactive power transmitted by the wireless charging transmitting device 1010. In this specification, the power receiving module 1001 may be a power receiving coil. The power receiving coil and the power transmitting coil (i.e., the power transmitting module 1012) in the wireless charging transmitting device 1010 transfer energy through electromagnetic induction. The compensation network at the power transmitting end and the compensation network at the power receiving end in the wireless charging system provided in this application may be selectively combined in any manner. Common combinations of compensation network structures include SS (series-series) type, PP (parallel-parallel) type, SP (series-parallel) type, PS (parallel-series) type, LCL-LCL (inductor capacitor inductor-inductor capacitor inductor) type, LCL-P (inductor capacitor inductor-parallel) type, and LCC-LCC (inductor capacitor capacitor-inductor capacitor capacitor) type, etc. This may be determined according to the requirements of the actual application scenario, and is not limited in this application.

[0074] The receiving conversion module 1002 can be configured to convert the high frequency resonant current and high frequency resonant voltage received by the power receiving module 1001 into the DC voltage and DC required to charge the energy storage module 1005. The receiving conversion module 1002 usually includes a receiving end compensation network and a rectifier unit (or called a rectifier circuit). The rectifier unit converts the high frequency resonant current and high frequency resonant voltage received by the power receiving module 1001 into the DC voltage and DC. If the voltage output by the rectifier unit cannot meet the requirements of the energy storage module, a DC conversion unit can be further added to the receiving conversion module 1002 for voltage regulation.

[0075] The receiving control module 1003 may be configured to control the adjustment of voltage, current and frequency conversion parameters of the receiving conversion module 1002 according to the receiving power requirements of wireless charging in an actual application scenario.

[0076] The receiving communication module 1004 may be configured to perform wireless communication between the wireless charging receiving device 1000 and the wireless charging transmitting device 1010, including communication transmission of information such as power control information, fault protection information, on / off information, and interactive authentication information. The function of the receiving communication module 1004 corresponds to the function of the transmitting communication module 1014 in the wireless charging transmitting device 1010, and the details will not be described again in this specification.

[0077] In the wireless charging system shown in FIG. 1 or FIG. 2, there is a certain space gap between the wireless charging transmitting device 1010 and the wireless charging receiving device 1000. Therefore, in the process of charging an electric vehicle by the wireless charging system, if there is a foreign object such as a coin or tin foil in the space gap, the foreign object will cause a vortex effect under the action of the high-frequency electromagnetic field. As a result, the temperature of the foreign object will rise rapidly, which may cause a risk such as a fire. Therefore, foreign object detection needs to be performed to ensure the safety of the wireless charging system and the device to be charged.

[0078] In the prior art, whether a foreign object exists is usually determined based on a change in an electrical parameter caused by a change in the physical characteristics of one or more foreign object detection coils disposed between the power transmitting device and the power receiving device. For example, the value of the current or voltage of the foreign object detection coil is detected by using an analog circuit, and whether a foreign object exists in the space gap is directly determined based on the current or voltage of the foreign object detection coil. In another example, the current or voltage parameter detected by the analog circuit may alternatively be sent to a controller, which processes the current or voltage parameter to obtain a corresponding phase angle or frequency parameter, and then determines whether a foreign object exists in the space gap based on the phase angle or frequency parameter. However, the conventional foreign object detection solutions usually suffer from problems of low detection accuracy or high system complexity. As a result, the reliability and applicability of the conventional foreign object detection solutions are low.

[0079] Therefore, the technical problem to be addressed in this application is how to simply and accurately implement foreign object detection. [Embodiment 1]

[0080] In order to solve the above-mentioned problems, an embodiment of the present application provides a foreign object detection device. The foreign object detection device is applicable to the wireless charging system shown in Fig. 1 or Fig. 2. The foreign object detection device can be configured to detect and determine whether a foreign object exists in the space gap between the wireless charging receiving device 1000 and the wireless charging transmitting device 1010 in the wireless charging system shown in Fig. 1 or Fig. 2.

[0081] 3 is a schematic diagram of the structure of a foreign object detection device according to an embodiment of the present application. As shown in FIG. 3, the foreign object detection device may mainly include a controller 30, a first resonant network 31, a signal coupler 32 and a phase difference detector 33. The controller 30 is connected to one end of the phase difference detector 33, the other end of the phase difference detector 33 is connected to one end of the signal coupler 32, and the other end of the signal coupler 32 is connected to one end of the first resonant network 31.

[0082] During actual operation, the first resonant network 31 may receive an excitation signal (herein denoted as S1) and operate normally under the action of the excitation signal S1. When the first resonant network 31 operates normally under the action of the excitation signal S1, the signal coupler 32 may obtain a current signal corresponding to the first resonant network 31 (for ease of distinction, in the following description, referred to as a resonant current signal S2). It should be understood that in this specification, the resonant current signal S2 indicates the value of the current flowing through the first resonant network 31 when the first resonant network 31 operates normally under the action of the excitation signal S1. The signal coupler 32 may further receive a preset carrier signal (herein denoted as S3) and couple the preset carrier signal S3 to the resonant current signal S2 to obtain a combined current signal (herein denoted as S4). It should be noted that it is necessary to ensure that the frequencies of the preset carrier signal S3 and the excitation signal S2 are the same. The preset carrier signal S3 may be a signal having any waveform and any suitable signal amplitude, and the excitation signal S1 may also be a signal having any waveform and any suitable signal amplitude. This is not limited in the present application. The phase difference detector 33 may receive the combined current signal S4 output by the signal combiner 32, extract a low-frequency signal component contained in the combined current signal S4, and determine a phase difference signal (herein indicated as S5) based on the low-frequency signal component. In this specification, the low-frequency signal component is a signal component having a signal frequency less than or equal to the first preset frequency and contained in the combined circuit signal S4. Then, the phase difference detector 33 may send the phase difference signal S5 to the controller 30. In this specification, the amplitude of the phase difference signal S5 correspondingly indicates the value of the phase difference between the excitation signal S1 and the resonant current signal S2. Then, the controller 30 may determine whether a foreign object exists in the detection area corresponding to the first resonant network 31 based on the amplitude of the phase difference signal S5. It should be noted herein that the detection area corresponding to the first resonant network 31 may be determined based on the shape and size of the first resonant network 31 .The controller 30 may be implemented by using a framework-based modular system, or may be implemented by using a system-on-chip including a single integrated chip, which is not a limitation in this application.

[0083] It can be seen from the working principle of the resonant network that, when the physical characteristics of the components in the resonant network remain unchanged, the output signal of the resonant network (current signal or voltage signal, the current signal is used as an example for the description in this application) and the excitation signal of the resonant network are theoretically perfectly overlapped and have the same phase and amplitude. When there are some foreign objects around the resonant network, the foreign objects may cause the changes of the physical characteristics of the components in the resonant network. As a result, the phase and amplitude of the output signal of the resonant network will change to a certain extent with respect to the excitation signal. According to this principle, the foreign object detection device provided in this application can directly detect the phase difference signal S5, which can indicate the phase difference between the excitation signal S1 of the first resonant network 31 and the resonant current signal S2 corresponding to the excitation signal S1 of the first resonant network 31, by using the signal coupler 32 and the phase difference detector 33, and can perform simple processing on the phase difference signal S5 by using the controller 30 to determine whether there is a foreign object in the detection area corresponding to the first resonant network 31. The foreign object detection device provided in the present application uses the signal coupler 32 and the phase difference detector 33 to directly detect the phase difference signal S5, which may indicate the phase difference between the excitation signal S1 and the resonant current signal S2, and then performs simple processing on the phase difference signal S5 to implement foreign object detection. This reduces the overall system complexity and cost compared to the conventional method in which a controller processes the current or voltage parameters detected by an analog circuit to obtain a phase angle or frequency parameter, and then performs foreign object detection based on the phase angle or frequency parameter. In addition, the foreign object detection device provided in the present application uses the phase difference signal to determine whether a foreign object is present. This avoids the problem that the current or voltage parameters are interfered with by the primary power, resulting in low detection accuracy, in the method in which foreign object detection is directly performed based on the measured current or voltage parameters. Therefore, the foreign object detection device provided in the present application can reduce the cost of foreign object detection and improve the accuracy and reliability of foreign object detection.

[0084] In some possible implementations, FIG. 4 is a schematic diagram of another structure of a foreign object detection device according to an embodiment of the present application. As shown in FIG. 4, the first resonant network 31 may include a first port 310, a second port 311, a resonant capacitor C1 and an inductor coil L1. One end of the resonant capacitor C1 is connected to the second port 311, the other end of the resonant capacitor C1 is connected to one end of the inductor coil L1, and the other end of the inductor coil L1 is connected to the first port 310. During actual operation, the second port 311 is configured to receive an excitation signal S1 and transmit the excitation signal S1 to the resonant capacitor C1. Resonance occurs between the resonant capacitor C1 and the inductor coil L1, and the current flowing through the inductor coil L1 is finally output through the first port 310.

[0085] It should be noted that in this specification, the resonant capacitor C1 and the inductor coil L1 shown in FIG. 4 are connected in a series resonant manner, and the connection manner is only an example. During practical implementation, the resonant capacitor C1 and the inductor coil L1 may alternatively be connected in a parallel resonant manner. This is not limited in this application. The inductor coil L1 may be an inductor coil of any shape and with any number of turns. When a foreign object (especially a metal foreign object) approaches the inductor coil, the physical characteristics (e.g., impedance characteristics) of the inductor coil will change, and the current and voltage of the inductor coil will change as a result. It should be noted that the capacitance of the resonant capacitor C1 can be determined based on the impedance characteristics of the inductor coil L1. Specifically, the capacitance of the resonant capacitor C1 needs to be matched and selected based on the impedance characteristics of the inductor coil L1.

[0086] It is further noted herein that the conclusion obtained through multiple tests on the first resonant network 31 provided in this application is that a foreign object causes a larger phase change between the excitation signal S1 and the resonant current signal S2 in series resonance. Therefore, preferably, the resonant capacitor C1 and the inductor coil L1 are connected in a series resonant manner. This can improve the accuracy of foreign object detection.

[0087] The present embodiment of the present application further provides several possible specific implementations of the signal combiner 32. In the following, the several possible specific implementations will be described in detail separately.

[0088] [Specific implementation of signal combiner 1]

[0089] 5 is a schematic diagram of another structure of a foreign object detection device according to an embodiment of the present application. As shown in FIG. 5, the signal coupler 32 may include a first inverter 321, a signal selector 322, a third port 323, a fourth port 324, and a fifth port 325. One end of the first inverter 321 is connected to the first port 310 of the first resonant network 31 through the third port 323, and the other end of the first inverter 321 is connected to one end of the signal selector 322. The other end of the signal selector 322 is connected to the fourth port 324. The other end of the signal selector 322 is connected to one end of the phase difference detector 33 through the fifth port 325. The other end of the signal selector 322 is connected to the first port of the first resonant network 31 through the third port 323.

[0090] During actual operation, when the first resonant network 31 is operating normally under the action of the excitation signal S1, the first inverter 321 may receive the resonant current signal S2 corresponding to the first resonant network 31 through the third port 323, perform a 180 degree phase shift on the resonant current signal S2 to obtain an anti-resonant current signal corresponding to the resonant current signal (specifically, the phase difference between the anti-resonant current signal and the resonant current signal is 180 degrees, and the anti-resonant current signal is denoted as S6 in this specification), and send the anti-resonant current signal S6 to the signal selector 322. The signal selector 322 may further receive a preset carrier signal S3 through the fourth port 324, and select the anti-resonant current signal S6 coming from the first inverter 321 or the resonant current signal S2 coming from the third port 323 as the combined current signal S4 according to the preset carrier signal S3, and send the combined current signal S4 to the phase difference detector 33 through the fifth port 325. The signal selector 322 may select the resonant current signal S2 or the anti-resonant current signal S6 as the output combined current signal S4 based on the value of the signal amplitude of the preset carrier signal S3. For example, after receiving the preset carrier signal S3, if the signal selector 322 determines that the signal amplitude of the preset carrier signal S3 is greater than or equal to a fourth preset amplitude, the signal selector 322 may use the resonant current signal S2 as the combined current signal S4 and output the combined current signal S4 through the fifth port 325. If the signal selector 322 determines that the signal amplitude of the preset carrier signal S3 is less than the fourth preset amplitude, the signal selector 322 may use the anti-resonant current signal S6 as the combined current signal S4 and output the combined current signal S4 through the fifth port 325.

[0091] Preferably, the excitation signal S1 may be a sine signal, the preset carrier signal S3 may be a square wave signal, and the phase difference between the excitation signal S1 and the preset carrier signal S3 is 90 degrees.

[0092] In the following, the operation principles of the first inverter 321 and the signal selector 322 will be described by using several examples with reference to specific examples of the aforementioned signals.

[0093] The excitation signal S1 is a sine signal

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[0094] In actual operation, the first inverter 321 first performs a 180 degree phase shift on the received resonant current signal S2 to obtain an anti-resonant current signal S6, that is, the anti-resonant current signal

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[0095] For example, FIG. 7 is a schematic diagram of signal coupling according to an embodiment of the present application. As shown in FIG. 7, when there is no foreign object in the detection area, the resonant current signal S2 is completely overlapped with the excitation signal S1, and the waveforms of the resonant current signal S2, the anti-resonant current signal S6 and the preset carrier signal S3 are shown in part (a) in FIG. 7. The combined current signal S4 obtained through the combination of the preset carrier signal S3 by the signal selector 322 is shown in part (b) in FIG. 7. Therefore, based on the equations of the preset carrier signal S3, the resonant current signal S2 and the anti-resonant current signal S6, and the operation principle of the signal selector 322, it can be determined that when there is no foreign object in the detection area, the combined current signal S4 should satisfy the following relationship (1):

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[0096] For another example, FIG. 8 is another schematic diagram of signal coupling according to an embodiment of the present application. When there is a foreign object in the detection area, the phase and amplitude of the resonant current signal S2 and the excitation signal S1 are different. The waveforms of the resonant current signal S2, the anti-resonant current signal S7 and the preset carrier signal S3 are shown in part (a) in FIG. 8. The combined current signal S4 obtained through the combination of the preset carrier signal S3 by the signal selector 322 is shown in part (b) in FIG. 8. Therefore, based on the equations of the preset carrier signal S3, the resonant current signal S2 and the anti-resonant current signal S6, and the operation principle of the signal selector 322, it can be determined that when there is a foreign object in the detection area, the combined current signal S4 should satisfy the following relationship (2):

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[0097] In the above implementation, the combined current signal S4 is obtained through combination by the first inverter 321 and the signal selector 322, which has a simple structure and is widely used, thereby reducing the cost of the foreign object detection device, simplifying the structure of the foreign object detection device, and improving the stability and robustness of the foreign object detection device.

[0098] Optionally, FIG. 9 is a schematic diagram of another structure of a foreign object detection device according to an embodiment of the present application. As shown in FIG. 9, the signal combiner 32 may further include a follower 326. One end of the signal selector 322 is connected to the third port 323 through the follower 326. During actual operation, the follower 326 is configured to implement phase tracking, so that the phase of the resonant current signal S2 does not change during transmission between the third port 323 and the signal selector 322. By using the follower 326, the phase change of the resonant current signal S2 caused by interference during transmission can be avoided. This ensures that a more accurate phase difference can be detected thereafter.

[0099] Furthermore, Figure 10 is a schematic diagram of the structure of a signal combiner according to an embodiment of the present application. As shown in Figure 10, the signal selector 322 in the signal combiner 32 may include a first switching transistor 3221, a second switching transistor 3222 and a second inverter 3223. A first end of the first switching transistor 3221 is connected to one end of the second inverter 3223, and the other end of the second inverter 3223 is connected to the fourth port 324. A first end of the second switching transistor 3222 is connected to the fourth port 324. A second end of the first switching transistor 3221 is connected to the third port 323 through a follower 326, and a second end of the second switching transistor 3222 is connected to the third port 323 through the first inverter 321. Both the third end of the first switching transistor 3221 and the third end of the second switching transistor 3222 are connected to the fifth port 325. In other words, the preset carrier signal is input to the first end of the first switching transistor 3221 through the second inverter 3223, and the preset carrier signal is also input to the first end of the second switching transistor 3222. The resonant current signal is input to the second end of the first switching transistor 3221, and the anti-resonant current signal is input to the second end of the second switching transistor 3222. The third end of the first switching transistor 3221 is connected to the third end of the second switching transistor 3222 and serves as the output end of the signal selector 322. In this implementation, the signal selector 322 is implemented by using switching transistors and inverters, which have a stable structure and are cost-effective. This can facilitate the integration of the signal selector 322 and further reduce the implementation cost of the foreign object detection device.

[0100] During actual operation, in some periods, the preset carrier signal S3 may enable the first switching transistor 3221 to be turned on through the second inverter 3223, and the preset carrier signal S3 may enable the second switching transistor 3222 to be turned off, so that the resonant current signal S2 may be output as the combined current signal S4 through the fifth port 325. In some other periods, the preset carrier signal S3 may enable the first switching transistor 3221 to be turned off through the second inverter 3223, and the preset carrier signal S3 may enable the second switching transistor 3222 to be turned on, so that the anti-resonant current signal S7 is output as the combined current signal S4 through the fifth port 325. It should be noted herein that, in order to enable the first switching transistor 3221 and the second switching transistor 3222 to be switched between two switch states, i.e., an on state and an off state, under the control of the preset carrier signal S3, the signal amplitude A_2 of the preset carrier signal S3 should be greater than or equal to the switch-on voltages of the first switching transistor 3221 and the second switching transistor 3222. It should be understood herein that the switch-on voltages of the first switching transistor 3221 and the second switching transistor 3222 may be the same or different. For ease of explanation, a scenario in which the switch-on voltages of the first switching transistor 3221 and the second switching transistor 3222 are equal to the fourth preset amplitude is used below as an example for explanation.

[0101] With reference to the structure shown in FIG. 10 and the above description of the preset carrier signal S3, the following describes the operation principle of the signal selector 322 by using an example. In this specification, it is assumed that the third preset amplitude is A4, and A2 is greater than A4. As mentioned above, the preset carrier signal

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[0102] Similarly,

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[0103] It should be noted that in this specification, the first switching transistor 3221 and the second switching transistor 3222 shown in FIG. 10 are metal oxide semiconductor field effect transistors (MOSFETs, MOS transistors for short). FIG. 10 is only an example. In practical applications, the switching transistors in this embodiment of the present application (e.g., the first switching transistor 3221 and the second switching transistor 3222) may alternatively be of another type. For example, the switching transistors in this application may alternatively be insulated gate bipolar transistors (IGBTs) or silicon carbide metal oxide semiconductor field effect transistors (SiC MOSFETs). This is not limited in this application. When the first switching transistor 3221 and the second switching transistor 3222 are IGBT transistors, the first ends of the first switching transistor 3221 and the second switching transistor 3222 are bases, the second ends of the first switching transistor 3221 and the second switching transistor 3222 are collectors, and the third ends of the first switching transistor 3221 and the second switching transistor 3222 are emitters. When the first switching transistor 3221 and the second switching transistor 3222 are MOS transistors, the first ends of the first switching transistor 3221 and the second switching transistor 3222 are gates, the second ends of the first switching transistor 3221 and the second switching transistor 3222 are drains, and the third ends of the first switching transistor 3221 and the second switching transistor 3222 are sources.

[0104] It is further noted herein that the inverters (e.g., the first inverter 321 and the second inverter 3223) in specific implementation 1 may be any implementation of a device or circuit that can perform a 180 degree phase shift on an input signal, such as a complementary metal-oxide semiconductor (CMOS) inverter or a transistor-transistor logic (TTL) NAND gate circuit, which is not limited in this application.

[0105] [Specific implementation of signal combiner 2]

[0106] 11 is a schematic diagram of another structure of a foreign object detection device according to an embodiment of the present application. As shown in FIG. 11, the signal combiner 32 may include a multiplier / analog multiplication circuit 326, a third port 323, a fourth port 324 and a fifth port 325. A first end of the multiplier / analog multiplication circuit 326 is connected to the first port 310 of the first resonant network 31 through the third port 323. A second end of the multiplier / analog multiplication circuit 326 is connected to the fourth port 324. A third end of the multiplier / analog multiplication circuit 326 is connected to one end of the phase difference detector 33 through the fifth port 325.

[0107] During actual operation, the multiplier / analog multiplier circuit 326 may be configured to multiply the resonant current signal S2 received by the multiplier / analog multiplier circuit 326 through the third port 323 with the preset carrier signal S3 received by the multiplier / analog multiplier circuit 326 through the fourth port 324 to obtain a combined current signal S4 (it is noted herein that the description of these signals in specific implementation 1 is further used in specific implementation 2). It is noted herein that the preset carrier signal S3 and the excitation signal S1 may be sinusoidal signals having the same frequency in this implementation.

[0108] For example, the preset carrier signal S3 is a sine signal

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[0109] It should be noted that in this specification, the multiplier / analog multiplication circuit 326 may be any implementation of a device or circuit that can perform multiplication on an input signal. The specific implementation of the multiplier / analog multiplication circuit 326 is not limited in this application.

[0110] In the above implementation, a multiplier or an analog multiplication circuit is used to perform signal combining on the preset carrier signal S1 and the resonant current signal S2. This method is simple and easy to implement, and can improve the efficiency of foreign object detection.

[0111] Further, see Fig. 5. After obtaining the combined current signal S4 through coupling, the signal combiner 32 may send the combined current signal S4 to the phase difference detector 33. After receiving the combined current signal S4, the phase difference detector 33 may filter the combined current signal S4 to extract low-frequency signal components having frequencies less than or equal to a first preset frequency from the combined current signal S4. Then, the phase difference detector 33 may determine a phase difference signal S5 based on the low-frequency signal components, and send the phase difference signal S5 to the controller 30.

[0112] With reference to the contents in the specific implementation 1 and the specific implementation 2 of the signal coupler, the principle of detecting the phase difference signal S5 by the phase difference detector 33 will be described in detail below. As mentioned above, in the specific implementation 1 of the signal coupler, when there is no foreign object in the detection area, the combined current signal S4 satisfies the formula (1); or when there is a foreign object in the detection area, the combined current signal S4 satisfies the formula (2). It can be seen from the formula (1) or the formula (2) that the combined current signal S4 is equivalent to the product of the resonant current signal S2 and a square wave signal having an amplitude (1,-1) and the same frequency as that of the resonant current signal S2. It can be seen from the signal processing principle that the fundamental wave of the square wave signal is a sine wave. Therefore, the process described in the specific implementation 1 of the signal coupler 32 of combining the preset carrier signal S3 with the resonant current signal S2 to obtain the combined current signal S4 is essentially equivalent to the process of multiplying the resonant current signal S2 with a sine signal having the same frequency as that of the resonant current signal S2. The fundamental of the square wave signal (herein denoted as S7) is

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[0113] Optionally,

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[0114] It should be noted that in practical applications, the phase difference detector 33 may be any implementation of a device or circuit that can filter high-frequency signal components in the combined current signal S4, such as a common inductor filter, a capacitor filter, or an L-type filter. The specific implementation of the phase difference detector 33 is not limited in this application.

[0115] In addition, the present embodiment of the present application further provides several implementations for the controller 30 to determine whether there is a foreign object in the detection area based on the phase difference signal S5. In the following, several possible specific implementations will be described separately in detail. In this specification, the phase difference signal S5

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[0116] [Judgment method 1]

[0117] After obtaining the phase difference signal S5, the controller 30 may first determine the amplitude of the phase difference signal S5. In this specification, referring to the above example, the amplitude of the phase difference signal S5 is

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[0118] In the above implementation, foreign object detection is performed directly through the amplitude of the phase difference signal S5 and the comparison between the values ​​of the first preset amplitude and the second preset amplitude. This method is simple and easy to implement, can reduce the requirements for the data processing capability of the controller 30, and can reduce the cost of foreign object detection.

[0119] [Judgment method 2]

[0120] 12 is a schematic diagram of another structure of a foreign object detection device according to an embodiment of the present application. As shown in FIG. 12, the foreign object detection device may further include an amplitude detector 34. One end of the amplitude detector 34 is connected to one end of the signal coupler 32, and the other end of the amplitude detector 34 is connected to the controller 30. During actual operation, the amplitude detector 34 may receive the combined current signal S4 from the signal coupler 32, detect the signal amplitude of the combined current signal S4 (for ease of understanding, in the following description, referred to as target signal amplitude), and send the target signal amplitude to the controller 30. It should be noted that in this specification, the amplitude detector 34 may be any implementation form of a device or circuit that can detect the amplitude of a current signal. The specific implementation form of the amplitude detector 34 is not limited in this application.

[0121] Furthermore, the controller 30 may determine whether a foreign object is present in the detection area corresponding to the first resonant network 31 based on the target signal amplitude and the amplitude of the phase difference signal S5. Referring to the above, the amplitude of the phase difference signal S5 is determined based on the phase difference between the excitation signal S1 and the resonant current signal S2 (i.e.,

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[0122] In a first optional specific implementation, the controller 30 may determine the amplitude of the phase difference signal S5, and then calculate a quotient (denoted as R1 in this specification for ease of explanation) of the amplitude of the phase difference signal S5 and the target signal amplitude. Then, if the controller 30 determines that the quotient R1 is greater than the second preset threshold and less than the first preset threshold, the controller 30 may determine that no foreign object exists in the detection area corresponding to the first resonant network 31. If the controller 30 determines that the quotient R1 is less than or equal to the second preset threshold, or greater than or equal to the first preset threshold, the controller 30 may determine that a foreign object exists in the detection area corresponding to the first resonant network 31. For example, referring to the above example, the phase difference signal S5 is:

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[0123] In this specification, the quotient R1 of the amplitude of the phase difference signal S5 and the target signal amplitude is related only to the phase difference between the excitation signal S1 and the resonant current signal S2. Therefore, the controller 30 determines whether or not a foreign object is present in the detection area based on the quotient R1 of the amplitude of the phase difference signal S5 and the target signal amplitude. This makes it possible to avoid cases where it is not possible to accurately and directly determine whether or not a foreign object is present in the detection area based on the amplitude of the phase difference signal S5 due to changes in the amplitude of the resonant current signal S2, thereby improving the detection accuracy of the foreign object detection device.

[0124] In a second optional specific implementation, the controller 30 may determine a quotient (also referred to as R1 in this specification) of the amplitude of the phase difference signal S5 and the amplitude of the phase difference signal S5 after determining the target signal amplitude and the amplitude of the phase difference signal S5. Then, if the controller 30 determines that the target signal amplitude is greater than or equal to the third preset amplitude, and the quotient R1 is greater than or equal to the first preset threshold, or less than or equal to the second preset threshold, the controller 30 determines that a foreign object exists in the detection area corresponding to the first resonant network 31. If the controller 30 determines that the target signal amplitude is less than the third preset amplitude, or the quotient R1 is greater than the second preset threshold and less than the first preset threshold, the controller 30 determines that a foreign object does not exist in the detection area corresponding to the first resonant network 31.

[0125] In this specification, the value of the amplitude of the phase difference signal S5 is further related to the target signal amplitude of the resonant current signal S2, and the value of the target signal amplitude is further related to the size of the object in the detection area (the object may be a foreign object or a non-foreign object, e.g., a structure such as a body or chassis of an electric vehicle). Therefore, in the above implementation, the judgment is performed based on both the value of the target signal amplitude and the value of the quotient R1. This can avoid cases where a non-foreign object structure (e.g., a structure such as a body or chassis of an electric vehicle) is recognized as a foreign object, and can improve the detection accuracy of the foreign object detection device.

[0126] In some optional implementations, Fig. 13 is a schematic diagram of another structure of a foreign object detection device according to an embodiment of the present application. As shown in Fig. 13, the foreign object detection device may further include a signal generator 35. The controller 30 is connected to the first resonant network 31 and the signal coupler 32 through the signal generator 35. Specifically, one end of the signal generator 35 is connected to the controller 30, the other end of the signal generator 35 is connected to the first resonant network 31, and the other end of the signal generator 35 is connected to one end of the signal coupler 32.

[0127] During actual operation, the controller 30 may generate a signal control command corresponding to the first resonant network 31, and the signal control command may indicate the signal frequencies of the excitation signal S1 and the preset carrier signal (in this specification, it is assumed that the signal frequencies of the excitation signal S1 and the preset carrier signal S3 are f1). Then, the controller 30 may send the signal control command to the signal generator 35. After receiving the signal control command, the signal generator 35 may generate the excitation signal S1 and the preset carrier signal S3 having the frequency f1.

[0128] It should be noted that the signal waveforms and / or signal amplitudes of the excitation signal S1 and the preset carrier signal S3 may be preconfigured by the signal generator 35, or may be indicated in real time by the controller 30 using signal control instructions, which is not limited in this application.

[0129] In practical applications, the signal generator 35 may be any implementation of a device or circuit that can generate signals with different frequencies, different waveforms, or different amplitudes. The specific implementation of the signal generator 35 is not limited in this application.

[0130] In some optional implementations, FIG. 14 is a schematic diagram of another structure of a foreign object detection device according to an embodiment of the present application. As shown in FIG. 14, the foreign object detection device may further include a switching module 36 and a second resonant network 37. The switching module 36 is connected to the controller 30, the signal generator 35, the first resonant network 31, and the second resonant network 37. The switching module 36 may be configured to determine whether the excitation signal S1 generated by the signal generator 35 is sent to the first resonant network 31 or the second resonant network 37 based on a resonant network selection signal coming from the controller 30. In other words, the switching module 36 may be configured to select the first resonant network 31 or the second resonant network 37 for foreign object detection based on a resonant network selection signal coming from the controller 30 to detect different detection areas.

[0131] It should be understood that in this specification, FIG. 14 only shows the first resonant network 31 and the second resonant network 37. However, during practical implementation, the foreign object detection device may further include resonant networks other than the first resonant network 31 and the second resonant network 37, and the switching module 36 may be configured to select a different resonant network for foreign object detection based on the indication of the controller 30. The connection manner and operation principle of the resonant networks other than the first resonant network 31 and the second resonant network 37 are similar to that of the second resonant network 37. Therefore, in order to avoid repetition, the structure shown in FIG. 14 is used hereinafter as an example for explanation.

[0132] It is further noted herein that the second resonant network 37 and the first resonant network 31 may have the same structure (i.e., may include the same resonant capacitors and coils), but are mounted at different locations within the foreign object detection device (i.e., corresponding to different detection areas). Alternatively, the second resonant network 37 and the first resonant network 31 may have different structures (i.e., may include different resonant capacitors and coils) and be mounted at different positions (i.e., corresponding to different detection areas) in the foreign object detection device. It can be seen from the operational characteristics of the resonant networks that resonance can occur only when the frequency of the excitation signal of a certain resonant network is the same as the resonant frequency of that resonant network. Therefore, the frequencies of the excitation signals required by resonant networks with different structures are also different. Specifically, when the second resonant network 37 and the first resonant network 31 have different structures, the frequency of the excitation signal generated by the signal generator 35 for the second resonant network 37 is also different from the frequency of the excitation signal generated by the signal generator 35 for the first resonant network 31. For ease of understanding, a specific scenario in which the second resonant network 37 and the first resonant network 31 have different structures and different mounting positions is used below as an example to explain the specific function of the switching module 36.

[0133] During actual operation, the controller 30 may determine whether to perform foreign object detection through the first resonant network 31 or the second resonant network 37. Optionally, the controller 30 may determine whether to perform foreign object detection through the first resonant network 31 or the second resonant network 37 according to a user command received by the controller 30. Alternatively, the controller 30 may determine whether to perform foreign object detection through the first resonant network 31 or the second resonant network 32 based on a preset trigger mechanism of the controller 30. For example, the trigger mechanism may be to perform foreign object detection through the first resonant network 31 at time t1 and to perform foreign object detection through the second resonant network 37 at time t2. If the controller 30 determines to perform foreign object detection through the first resonant network 31, the controller 30 may generate a signal control command (for ease of distinction, referred to as a first signal control command in the following description) and send the first signal control command to the signal generator 35. The signal generator 35 may generate an excitation signal S1 having a frequency f1 and a preset carrier signal S3 according to the first signal control command, send the excitation signal S1 having a frequency f1 to the switching module 36, and send the preset carrier signal S3 having a frequency f1 to the signal coupler 32. In addition, the controller 30 may further generate a resonant network selection signal (for ease of distinction, in the following description, referred to as a first resonant network selection signal) and send the first resonant network selection signal to the switching module 36. After receiving the first resonant network selection signal, the switching module 36 may send the excitation signal having a frequency f1 to the first resonant network 31, which is received by the switching module 36. When the controller 30 determines to perform foreign object detection through the second resonant network 37, the controller 30 may generate a signal control command (for ease of distinction, referred to as a second signal control command in the following description. In this specification, it is assumed that the signal frequency indicated by the second signal control command is f2) and transmit the second signal control command to the signal generator 35.The signal generator 35 may generate an excitation signal S1 having a frequency f2 and a preset carrier signal S3 according to the second signal control command, send the excitation signal S1 having a frequency f2 to the switching module 36, and send the preset carrier signal S3 having a frequency f2 to the signal coupler 32. In addition, the controller 30 may further generate a resonant network selection signal (for ease of distinction, in the following description, referred to as a second resonant network selection signal) and send the second resonant network selection signal to the switching module 36. After receiving the second resonant network selection signal, the switching module 36 may send the excitation signal having a frequency f2 to the second resonant network 37, which is received by the switching module 36.

[0134] It should be noted herein that in actual implementation, the switching module 36 may be any implementation form of a multiplexer switch device or circuit. The switching module 36 may be a discrete switch device or an integrated analog switch chip, etc. The specific implementation form of the switching module 36 is not limited in this application.

[0135] In some optional implementations, Fig. 15 is a schematic diagram of another structure of a foreign object detection device according to an embodiment of the present application. As shown in Fig. 15, the foreign object detection device may further include a current detector 38. The first resonant network 31 is connected to the signal coupler 32 through the current detector 38. It should be noted that in this specification, the structure shown in Fig. 15 is also applicable to the structure shown in Fig. 14, and the second resonant network 37 and the switching module 36 are not shown in this specification for the sake of simplicity.

[0136] During actual operation, when the first resonant network 31 is operating normally under the action of the excitation signal S1, the current detector 38 may be configured to detect the current flowing through the first resonant network 31 and perform processing such as amplification on the current to convert the current into a resonant current signal S2.

[0137] It should be noted that in practical implementation, the current detector 38 may be any implementation type of device or circuit capable of implementing current detection. The specific implementation type of the current detector 38 is not limited in this application.

[0138] It is further noted that the preset parameters, such as the first preset amplitude, the second preset amplitude, the third preset amplitude, the first preset threshold and the second preset threshold, may be empirical values ​​obtained through multiple foreign object detection tests with the foreign object detection device provided in the present application.

[0139] It is further noted that the controller 30 may be any implementation of a device capable of performing operational processing and transmitting control instructions, such as a central processing unit (CPU), a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or another programmable logic device, a discrete gate or transistor logic device, or a discrete hardware component. The implementation of the controller 30 is not limited herein.

[0140] The foreign object detection device provided in the present application can directly detect the phase difference signal S6, which can indicate the phase difference between the excitation signal S1 input to the first resonant network 31 and the resonant current signal S2 output by the first resonant network 31, by using the signal coupler 32 and the phase difference detector 33, and can perform simple processing on the phase difference signal S6 by using the controller 30 to determine whether a foreign object exists in the detection area corresponding to the first resonant network. The foreign object detection device provided in the present application can directly detect the phase difference signal S5, which can indicate the phase difference between the excitation signal S1 and the resonant current signal S2, by using the signal coupler 32 and the phase difference detector 33, and provide the phase difference signal S5 to the controller 30 for further simple processing to implement foreign object detection. This reduces the overall system complexity and cost compared to the conventional method in which the controller processes the current or voltage parameters detected by an analog circuit to obtain the phase angle or frequency parameters. In addition, the foreign object detection device provided in the present application can determine whether a foreign object exists by using the phase difference signal. In this way, the problem of low detection accuracy due to interference from the primary power on the current or voltage parameters can be avoided in a manner where foreign object detection is directly performed based on the measured current or voltage parameters. Therefore, the foreign object detection device provided in this application can reduce the cost of foreign object detection and improve the accuracy and reliability of foreign object detection. [Embodiment 2]

[0141] 16 is a schematic flow chart of a foreign object detection method according to an embodiment of the present application. The foreign object detection method is applicable to the foreign object detection device described in embodiment 1. In this specification, the specific structure of the foreign object detection device and the function of each structure are described in embodiment 1, and the signals used during the execution of the foreign object detection method are also described in embodiment 1. As shown in FIG. 16, the method includes the following steps:

[0142] S101: When a first resonant network is operating normally under the action of an excitation signal, a signal coupler couples a resonant current signal corresponding to the first resonant network with a preset carrier signal to obtain a coupled current signal.

[0143] In some possible implementations, after the modules in the foreign object detection device are accurately connected and calibrated, the controller 30 may control the excitation signal S1 to be input to the first resonant network 31, so that the first resonant network 31 operates normally under the action of the excitation signal S1. In this specification, for the process in which the first resonant network 31 operates normally under the action of the excitation signal S1, please refer to the process described in the first embodiment in which the first resonant network 31 operates normally under the action of the excitation signal S1. Here, the details will not be described again. Then, after receiving the resonant current signal S2 and the preset carrier signal S3 corresponding to the first resonant network 31, the signal coupler 32 may combine the resonant current signal S2 with the preset carrier signal S3 to obtain a combined current signal S4. Then, the signal coupler 32 may send the combined current signal S4 to the phase difference detector 33.

[0144] In an optional implementation, the signal combiner 32 includes a first inverter 321 and a signal selector 322. The first inverter 321 may perform a 180-degree phase shift on the received resonant current signal S2 to obtain the anti-resonant current signal S6. For a specific process, refer to the process described in the first embodiment, in which the first inverter 321 performs a 180-degree phase shift on the received resonant current signal S2 to obtain the anti-resonant current signal S6. Details will not be described again here. Then, the signal selector 322 may select the resonant current signal S2 or the anti-resonant current signal S6 as the combined current signal based on a preset carrier signal.

[0145] Further, the signal selector 322 may include a first switching transistor 3221, a second switching transistor 3222 and a second inverter 3223. During actual operation, in some periods, the signal selector 322 may control the first switching transistor 3221 to be turned on by using a preset carrier signal S3 flowing through the second inverter 3223, and control the second switching transistor 3222 to be turned off by using a preset carrier signal, so that the resonant current signal S2 is output as the combined current signal S4. Alternatively, the signal selector may control the second switching transistor 3222 to be turned on by using a preset carrier signal S3, and control the first switching transistor 3221 to be turned off by using a preset carrier signal S3 flowing through the second inverter 3223, so that the anti-resonant current signal S6 is output as the combined current signal. In this specification, for the specific operation processes of the first switching transistor 3221, the second switching transistor 3222 and the second inverter 3223, please refer to the corresponding content described in embodiment 1. Here, the details will not be described again.

[0146] Optionally, in the above implementation, the excitation signal S1 may be a sine signal, the preset carrier signal S3 may be a square wave signal, and the phase difference between the excitation signal S1 and the preset carrier signal S3 is 90 degrees.

[0147] In another optional implementation, the signal combiner 32 may include a multiplier / analog multiplication circuit 326. The multiplier / analog multiplication circuit 326 may combine the received resonant current signal S2 with a preset carrier signal S3 to obtain a combined current signal S4. For a specific process, refer to the process described in embodiment 1, in which the multiplier / analog multiplication circuit 326 implements the combination. Details will not be described again here.

[0148] Optionally, in the above implementation, both the excitation signal S1 and the preset carrier signal S3 may be sinusoidal signals.

[0149] S102: A phase difference detector extracts low frequency signal components from the combined current signals and determines a phase difference signal based on the low frequency signal components.

[0150] In some possible implementations, the phase difference detector 33 may extract a low-frequency signal component from the combined current signal S4 output by the signal combiner 32, and then determine a phase difference signal based on the low-frequency signal component. In this specification, the low-frequency signal component is a signal component having a frequency less than or equal to the first preset frequency in the combined current signal S4. In this specification, for the specific process in which the phase difference detector 33 extracts a low-frequency signal component from the combined current signal S4 output by the signal combiner 32 and determines a phase difference signal based on the low-frequency signal component, please refer to the process described in embodiment 1, in which the phase difference detector 33 extracts a low-frequency signal component and determines a phase difference signal based on the low-frequency signal component. Details will not be described again here.

[0151] S103: The controller determines whether a foreign object is present in the detection area corresponding to the first resonant network based on the phase difference signal.

[0152] In some possible implementations, after obtaining the phase difference signal S5, the controller 30 may determine whether a foreign object is present in the detection area corresponding to the first resonant network 31 based on the phase difference signal S5.

[0153] In a first optional implementation, after obtaining the phase difference signal S5, the controller 30 may first determine the amplitude of the phase difference signal S5. In this specification, referring to the above example, the amplitude of the phase difference signal S5 is:

number

number

number

[0154] In a second optional implementation, the foreign object detection device may further include an amplitude detector 34. The controller 30 may control the amplitude detector 34 to detect the target signal amplitude of the resonant current signal S2. For a specific detection process, please refer to the corresponding description in the first embodiment. Here, the details will not be described again. Then, the controller 30 may determine whether a foreign object exists in the detection area corresponding to the first resonant network 31 based on the target signal amplitude and the amplitude of the phase difference signal S5.

[0155] Optionally, after determining the amplitude of the phase difference signal S5, the controller 30 may calculate a quotient (denoted as R1 in this specification for ease of explanation) of the amplitude of the phase difference signal S5 and the target signal amplitude. Then, if the controller 30 determines that the quotient R1 is greater than the second preset threshold and less than the first preset threshold, the controller 30 may determine that no foreign object is present in the detection area corresponding to the first resonant network 31. If the controller 30 determines that the quotient R1 is less than or equal to the second preset threshold, or greater than or equal to the first preset threshold, the controller 30 may determine that a foreign object is present in the detection area corresponding to the first resonant network 31.

[0156] Optionally, after determining the target signal amplitude and the amplitude of the phase difference signal S5, the controller 30 may determine a quotient (also referred to herein as R1) of the amplitude of the phase difference signal S5 and the target signal amplitude. Then, if the controller 30 determines that the target signal amplitude is greater than or equal to the third preset amplitude, and the quotient R1 is greater than or equal to the first preset threshold, or less than or equal to the second preset threshold, the controller 30 determines that a foreign object is present in the detection area corresponding to the first resonant network 31. If the controller 30 determines that the target signal amplitude is less than the third preset amplitude, or the quotient R1 is greater than the second preset threshold and less than the first preset threshold, the controller 30 determines that a foreign object is not present in the detection area corresponding to the first resonant network 31.

[0157] It is further noted that in some optional implementations, the foreign object detection device may further include a signal generator 35, and the controller 30 may use a signal control command to control the signal generator 35 to generate an excitation signal S1 having a corresponding frequency and a preset carrier signal S3. The excitation signal S1 and the preset carrier signal S3 may be indicated by a signal control command. For a specific process in which the controller 30 uses a signal control command to control the signal generator 35 to generate an excitation signal S1 having a corresponding frequency and a preset carrier signal S3, please refer to the process described in embodiment 1. Details will not be described again here.

[0158] In some optional implementations, the foreign object detection device may further include a current detector 38. When the first resonant network 31 is operating normally under the action of the excitation signal S1, the current detector 38 may detect the current flowing through the first resonant network 31, and perform processing such as amplification on the current to convert the current into a resonant current signal S2. In this specification, for the specific process of the current detector 38 detecting the resonant current signal S2, please refer to the corresponding content described in embodiment 1. Details will not be described again here.

[0159] In some optional implementations, the foreign object detection device may further include a switching module 36 and a second resonant network 37. The controller 30 may control the switching module 36 to select the first resonant network 31 or the second resonant network 37 for foreign object detection by using the resonant network selection signal to detect different detection areas. In this specification, for a specific process in which the controller 30 controls the switching module 36 to select the first resonant network 31 or the second resonant network 37 for foreign object detection by using the resonant network selection signal, please refer to the process described in the first embodiment. Details will not be described again here.

[0160] In this embodiment, the signal coupler 32 and the phase difference detector 33 may directly detect the phase difference signal S6, which may indicate the phase difference between the excitation signal S1 input to the first resonant network 31 and the resonant current signal S2 output by the first resonant network 31, and the controller 30 may perform simple processing on the phase difference signal S6 to determine whether there is a foreign object in the detection area corresponding to the first resonant network. In this manner, the complexity and cost of the entire detection system can be reduced, and the problem of low detection accuracy due to the current parameter or voltage parameter being interfered by the primary power can also be avoided in the manner in which foreign object detection is directly performed based on the measured current parameter or voltage parameter.

[0161] FIG. 17 is a schematic diagram of the structure of another wireless charging system according to an embodiment of the present application. As shown in FIG. 17, the present application further provides a wireless charging transmitting end device 170. The wireless charging transmitting end device 170 may include a power transmitting device 1701 and a foreign object detection device (herein indicated as 1702) described in embodiment 1 or embodiment 2. The wireless charging transmitting end device 170 corresponds to the wireless charging receiving end device 171, and the wireless charging receiving end device 171 may include a power receiving device 1711. The foreign object detection device 1702 may be disposed on the side of the power transmitting device 1701 facing the power receiving device 1711. In the process of the wireless charging transmitting end device 170 charging the wireless charging receiving end device 171, the foreign object detection device 1702 may be configured to detect whether a foreign object exists between the power receiving device 1711 and the power transmitting device 1701. It should be noted that in practical implementation, the power transmitting device 1701 corresponds to the wireless charging transmitting device 1010 shown in Figures 1 and 2. The power receiving device 1711 corresponds to the wireless charging receiving device 1000 shown in Figures 1 and 2. The power transmitting device 1701 may include a power transmitting coil. The power receiving device 1711 may include a power receiving coil. The foreign object detection device 1702 may be disposed on the side of the power transmitting coil facing the power receiving coil.

[0162] FIG. 18 is a schematic diagram of the structure of another wireless charging system according to an embodiment of the present application. As shown in FIG. 18, the present application further provides a wireless charging receiving end device 180. The wireless charging receiving end device 180 may include a power receiving device 1801 and a foreign object detection device (herein indicated as 1802) described in embodiment 1 or embodiment 2. The wireless charging receiving end device 180 corresponds to the wireless charging transmitting end device 181, and the wireless charging transmitting end device 181 may include a power transmitting device 1811. The foreign object detection device 1802 may be disposed on the side of the power receiving device 1801 facing the power transmitting device 1811. In the process of the wireless charging transmitting end device 181 charging the wireless charging receiving end device 180, the foreign object detection device 1802 may be configured to detect whether a foreign object exists between the power receiving device 1801 and the power transmitting device 1811. It should be noted that in practical implementation, the power transmitting device 1811 corresponds to the wireless charging transmitting device 1010 shown in Figures 1 and 2. The power receiving device 1801 corresponds to the wireless charging receiving device 1000 shown in Figures 1 and 2. The power transmitting device 1811 may include a power transmitting coil. The power receiving device 1801 may include a power receiving coil. The foreign object detection device 1802 may be disposed on the side of the power transmitting coil facing the power receiving coil.

[0163] In the description of this application, unless otherwise stated, it should be understood that " / " indicates "or". For example, A / B may indicate A or B. The term "and / or" in this specification describes only the correspondence between related objects and indicates that three relationships may exist. For example, A and / or B may represent three cases: only A exists, both A and B exist, and only B exists. In addition, "at least one" means one or more, and "multiple" means two or more. Terms such as "first" and "second" do not limit the number or execution order, and terms such as "first" and "second" do not indicate clear distinction.

[0164] In the present description, terms such as "example" or "for example" are used to provide an example, illustration, or explanation. Any embodiment or design scheme described in the present description as "example" or "for example" should not be construed as preferred or advantageous over another embodiment or design scheme. Strictly, terms such as "example" or "for example" are intended to present the relevant concept in a particular manner.

[0165] In combination with the examples described in the embodiments disclosed herein, those skilled in the art may recognize that the steps of the units and algorithms may be implemented by electronic hardware, computer software, or a combination thereof. In order to clearly describe the compatibility between hardware and software, the above generally describes the configurations and steps of the examples based on functions. Whether a function is performed by hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art may use different methods to implement the described functions for each specific application, but such implementation should not be considered to go beyond the scope of the present application.

[0166] In the embodiments provided in the present application, it should be understood that the disclosed system, device and method may be implemented in other ways. For example, the above-mentioned device is merely an example. For example, the division into multiple units is merely a logical division of functions, and may be divided in other ways in actual implementation. For example, multiple units or components may be combined or integrated into another system, or some functions may be ignored or not performed. In addition, the illustrated or described mutual couplings, direct couplings or communication connections may be indirect couplings or communication connections through some interfaces, devices or units, or may be electrical, mechanical or other forms of connection.

[0167] In addition, each functional unit in the embodiments of the present application may be integrated into one processing unit, each of these units may exist physically alone, or two or more units may be integrated into one unit. The integrated unit may be implemented in the form of hardware or in the form of a software functional unit.

[0168] In conclusion, the above description is only an exemplary embodiment of the technical solutions of the present application, and is not intended to limit the protection scope of the present application. Any modifications, equivalent replacements, or improvements made without departing from the spirit and principle of the present application shall be included in the protection scope of the present application. (Other possible items) (Item 1) A foreign object detection device comprising a controller, a first resonant network, a signal combiner, and a phase difference detector, the signal coupler is configured to obtain a resonant current signal corresponding to the first resonant network when the first resonant network is operating normally under the action of an excitation signal, couple a preset carrier signal to the resonant current signal to obtain a combined current signal, and send the combined current signal to the phase difference detector, where a frequency of the preset carrier signal is the same as a frequency of the excitation signal; the phase difference detector is configured to extract a low frequency signal component from the combined current signal, determine a phase difference signal based on the low frequency signal component, and transmit the phase difference signal to the controller, where the low frequency signal component is a signal component having a frequency less than or equal to a first preset frequency in the combined current signal, and an amplitude of the phase difference signal correspondingly indicates a phase difference between the excitation signal and the resonant current signal; and The controller is configured to determine whether a foreign object is present in a detection area corresponding to the first resonant network based on the amplitude of the phase difference signal. Foreign object detection device. (Item 2) the foreign object detection device further comprises a current detector; and When the first resonant network is operating normally under the action of the excitation signal, the current detector is configured to detect a current output by the first resonant network to obtain the resonant current signal, and send the resonant current signal to the signal coupler. 2. A foreign object detection device according to item 1. (Item 3) The signal combiner includes a first inverter and a signal selector; the first inverter is configured to perform a phase shift on the resonant current signal to obtain an anti-resonant current signal, where a phase difference between the anti-resonant current signal and the resonant current signal is 180 degrees; and The signal selector is configured to select the resonant current signal or the anti-resonant current signal as the output combined current signal based on the preset carrier signal. 3. A foreign object detection device according to item 1 or 2. (Item 4) The signal selector includes a first switching transistor, a second switching transistor and a second inverter; the preset carrier signal is input to a first end of the first switching transistor through the second inverter, the preset carrier signal is also input to a first end of the second switching transistor, the resonant current signal is input to a second end of the first switching transistor, the anti-resonant current signal is input to a second end of the second switching transistor, and a third end of the first switching transistor is connected to a third end of the second switching transistor and serves as an output end of the signal selector; and the predetermined carrier signal controls the first switching transistor through the second inverter to be turned on and the second switching transistor to be turned off, so that the resonant current signal is output as the combined current signal; or The preset carrier signal controls the second switching transistor to be turned on and controls the first switching transistor to be turned off through the second inverter, so that the anti-resonant current signal is output as the combined current signal. 4. A foreign object detection device according to item 3. (Item 5) 5. The foreign object detection device according to item 4, wherein the excitation signal is a sine signal, the preset carrier signal is a square wave signal, and a phase difference between the excitation signal and the preset carrier signal is 90 degrees. (Item 6) the signal combiner comprises a multiplier or an analog multiplication circuit; and The multiplier or the analog multiplication circuit is configured to multiply the preset carrier signal by the resonant current signal to obtain the combined current signal. 3. A foreign object detection device according to item 1 or 2. (Item 7) 7. The foreign object detection device according to claim 6, wherein the excitation signal and the preset carrier signal are sinusoidal signals. (Item 8) Specifically, the controller configured to determine an amplitude of the phase difference signal; and configured to determine that a foreign object is present in the detection area corresponding to the first resonant network when the amplitude of the phase difference signal is determined to be greater than or equal to a first preset amplitude or less than or equal to a second preset amplitude, where the first preset amplitude is greater than the second preset amplitude; or configured to determine that no foreign object is present in the detection area corresponding to the first resonant network when it is determined that the amplitude of the phase difference signal is smaller than the first preset amplitude and larger than the second preset amplitude. 8. A foreign object detection device according to any one of items 1 to 7. (Item 9) The foreign object detection device further comprises an amplitude detector; the amplitude detector is configured to detect a target signal amplitude of the resonant current signal; and The controller is configured to determine whether a foreign object is present in the detection area corresponding to the first resonant network based on the target signal amplitude and the amplitude of the phase difference signal. 8. A foreign object detection device according to any one of items 1 to 7. (Item 10) Specifically, the controller configured to determine an amplitude of the phase difference signal; configured to determine that a foreign object is present in the detection area corresponding to the first resonant network when a quotient of the amplitude of the phase difference signal and the target signal amplitude is determined to be greater than or equal to a first preset threshold or less than or equal to a second preset threshold; or configured to determine that no foreign object is present in the detection area corresponding to the first resonant network when it is determined that the quotient of the amplitude of the phase difference signal and the target signal amplitude is greater than the second preset threshold and less than the first preset threshold. 10. The foreign object detection device according to item 9. (Item 11) Specifically, the controller configured to determine an amplitude of the phase difference signal; configured to determine that a foreign object is present in the detection area corresponding to the first resonant network when it is determined that the target signal amplitude is greater than or equal to a third preset amplitude and a quotient of the amplitude of the phase difference signal and the target signal amplitude is greater than or equal to a first preset threshold or less than or equal to a second preset threshold; or and determining that no foreign object is present in the detection area corresponding to the first resonant network when it is determined that the target signal amplitude is smaller than the third preset amplitude, or when it is determined that the quotient of the amplitude of the phase difference signal and the target signal amplitude is greater than the second preset threshold and less than the first preset threshold. 10. The foreign object detection device according to item 9. (Item 12) The foreign object detection device further includes a signal generator, the signal generator comprising: configured to generate the preset carrier signal and the excitation signal according to a signal control command sent by the controller, where the frequencies of the preset carrier signal and the excitation signal are indicated by the signal control command; 12. A foreign object detection device according to any one of items 1 to 11. (Item 13) the foreign object detection device further comprises a second resonant network and a switching module, the second resonant network and the first resonant network being separately connected to the switching module; and The switching module is configured to determine whether the excitation signal generated by the signal generator is transmitted to the first resonant network or the second resonant network based on a resonant network selection signal coming from the controller. Item 13. A foreign object detection device according to item 12. (Item 14) A foreign object detection method applied to a foreign object detection device including a first resonant network, a signal coupler, a phase difference detector, and a controller, comprising: When the first resonant network is operating normally under the action of an excitation signal, the signal coupler couples a resonant current signal corresponding to the first resonant network with a preset carrier signal to obtain a combined current signal; the phase difference detector extracting a low frequency signal component from the combined current signal and determining a phase difference signal based on the low frequency signal component, where the low frequency signal component is a signal component having a frequency less than or equal to a preset frequency in the combined current signal, and a signal amplitude of the phase difference signal indicative of a phase difference between the excitation signal and the resonant current signal; and determining whether a foreign object is present in a detection area corresponding to the first resonant network based on the phase difference signal; A method comprising: (Item 15) the foreign object detection device further includes a current detector; and The method comprises: When the first resonant network is operating normally under the action of the excitation signal, the current detector detects a current output by the first resonant network to obtain the resonant current signal. Item 15. The method of item 14, further comprising: (Item 16) the signal combiner includes a first inverter and a signal selector; and When the first resonant network is operating normally under the action of an excitation signal, the signal coupler couples a resonant current signal corresponding to the first resonant network with a preset carrier signal to obtain a coupled current signal, the first inverter performing a phase shift on the resonant current signal to obtain an anti-resonant current signal, where a phase difference between the anti-resonant current signal and the resonant current signal is 180 degrees; and the signal selector selecting, based on the preset carrier signal, the resonant current signal or the anti-resonant current signal as the combined current signal to be output; have 16. The method according to item 14 or 15. (Item 17) the signal selector includes a first switching transistor, a second switching transistor and a second inverter, the preset carrier signal is input to a first end of the first switching transistor through the second inverter, the preset carrier signal is also input to a first end of the second switching transistor, the resonant current signal is input to a second end of the first switching transistor, the anti-resonant current signal is input to a second end of the second switching transistor, and a third end of the first switching transistor is connected to a third end of the second switching transistor and functions as an output end of the signal selector; and The step of the signal selector selecting the resonant current signal or the anti-resonant current signal as the combined current signal to be output based on the preset carrier signal, controlling the first switching transistor to be turned on by a predetermined carrier signal input to a first end of the first switching transistor and flowing through the second inverter, and controlling the second switching transistor to be turned off by a predetermined carrier signal input to a first end of the second switching transistor, so that the resonant current signal is output as the combined current signal; or controlling the second switching transistor to be turned on by a preset carrier signal input to a first end of the second switching transistor and controlling the first switching transistor to be turned off by a preset carrier signal input to a first end of the first switching transistor and flowing through the second inverter, so that the anti-resonant current signal is output as the combined current signal. Including, Item 17. The method according to item 16. (Item 18) the signal combiner includes a multiplier or an analog multiplication circuit; and When the first resonant network is operating normally under the action of an excitation signal, the signal coupler couples a resonant current signal corresponding to the first resonant network with a preset carrier signal to obtain a coupled current signal, said multiplier or said analog multiplication circuit multiplying said preset carrier signal by said resonant current signal to obtain said combined current signal; having 16. The method according to item 14 or 15. (Item 19) the foreign object detection apparatus further includes an amplitude detector; and The method comprises: said amplitude detector detecting a target signal amplitude of said resonant current signal. 19. The method of any one of items 14 to 18, further comprising: (Item 20) The step of the controller determining whether a foreign object is present in a detection area corresponding to the first resonant network based on the phase difference signal includes: the controller determining an amplitude of the phase difference signal; and determining that a foreign object is present in the detection area corresponding to the first resonant network when the controller determines that a quotient of the amplitude of the phase difference signal and the target signal amplitude is greater than or equal to a first preset threshold or less than or equal to a second preset threshold; or determining that a foreign object is not present in the detection area corresponding to the first resonant network when the controller determines that a quotient of the amplitude of the phase difference signal and the target signal amplitude is greater than the second preset threshold and less than the first preset threshold. having Item 19. The method according to item 19. (Item 21) The step of the controller determining whether a foreign object is present in a detection area corresponding to the first resonant network based on the phase difference signal includes: the controller determining an amplitude of the phase difference signal; and determining that a foreign object is present in the detection area corresponding to the first resonant network when the controller determines that the target signal amplitude is greater than or equal to a third preset amplitude and a quotient of the amplitude of the phase difference signal and the target signal amplitude is greater than or equal to a first preset threshold or less than or equal to a second preset threshold; or determining that no foreign object is present in the detection area corresponding to the first resonant network if the controller determines that the target signal amplitude is less than the third preset amplitude or if the controller determines that the quotient of the amplitude of the phase difference signal and the target signal peak is greater than the second preset threshold and less than the first preset threshold. having Item 19. The method according to item 19. (Item 22) A wireless charging transmitting end device comprising a power transmitting device and a foreign object detecting device according to any one of items 1 to 13, The foreign object detection device is disposed on a side of the power transmitting device facing a wireless charging power receiving device, and the power receiving device is included in a wireless charging receiving end device corresponding to the wireless charging transmitting end device. Wireless charging sending end device.

Claims

1. A foreign object detection apparatus comprising a controller, a first resonant network, a signal combiner, and a phase difference detector, the signal coupler is configured to obtain a resonant current signal corresponding to the first resonant network when the first resonant network is operating normally under the action of an excitation signal, couple a preset carrier signal to the resonant current signal to obtain a combined current signal, and send the combined current signal to the phase difference detector; the phase difference detector is configured to extract a low frequency signal component from the combined current signal, determine a phase difference signal based on the low frequency signal component, and transmit the phase difference signal to the controller, where the low frequency signal component is a signal component having a frequency less than or equal to a first preset frequency in the combined current signal, and an amplitude of the phase difference signal correspondingly indicates a phase difference between the excitation signal and the resonant current signal; and The controller is configured to determine whether a foreign object is present in a detection area corresponding to the first resonant network based on the amplitude of the phase difference signal. Foreign object detection device.

2. the foreign object detection device comprises a current detector; and When the first resonant network is operating normally under the action of the excitation signal, the current detector is configured to detect a current output by the first resonant network to obtain the resonant current signal, and send the resonant current signal to the signal coupler. The foreign object detection device according to claim 1 .

3. The signal combiner includes a first inverter and a signal selector; the first inverter is configured to perform a phase shift on the resonant current signal to obtain an anti-resonant current signal, where a phase difference between the anti-resonant current signal and the resonant current signal is 180 degrees; and The signal selector is configured to select the resonant current signal or the anti-resonant current signal as the output combined current signal based on the preset carrier signal.

3. A foreign object detecting device according to claim 1 or 2.

4. the signal selector includes a first switching transistor, a second switching transistor and a second inverter; the preset carrier signal is input to a first end of the first switching transistor through the second inverter, the preset carrier signal is also input to a first end of the second switching transistor, the resonant current signal is input to a second end of the first switching transistor, the anti-resonant current signal is input to a second end of the second switching transistor, and a third end of the first switching transistor is connected to a third end of the second switching transistor and functions as an output end of the signal selector; and the predetermined carrier signal controls the first switching transistor through the second inverter to be turned on and the second switching transistor to be turned off, so that the resonant current signal is output as the combined current signal; or The preset carrier signal controls the second switching transistor to be turned on and controls the first switching transistor to be turned off through the second inverter, so that the anti-resonant current signal is output as the combined current signal. The foreign object detecting device according to claim 3 .

5. 5. The foreign object detection device of claim 4, wherein the excitation signal is a sine signal, the preset carrier signal is a square wave signal, and a phase difference between the excitation signal and the preset carrier signal is 90 degrees.

6. the signal combiner comprises a multiplier or an analog multiplication circuit; and The multiplier or the analog multiplication circuit is configured to multiply the preset carrier signal by the resonant current signal to obtain the combined current signal.

3. A foreign object detecting device according to claim 1 or 2.

7. 7. The foreign object detecting apparatus of claim 6, wherein the excitation signal and the predetermined carrier signal are sinusoidal signals.

8. The controller: configured to determine an amplitude of the phase difference signal; and configured to determine that a foreign object is present in the detection area corresponding to the first resonant network when the amplitude of the phase difference signal is determined to be greater than or equal to a first preset amplitude or less than or equal to a second preset amplitude, where the first preset amplitude is greater than the second preset amplitude; or configured to determine that no foreign object is present in the detection area corresponding to the first resonant network when it is determined that the amplitude of the phase difference signal is smaller than the first preset amplitude and larger than the second preset amplitude. The foreign object detection device according to any one of claims 1 to 7.

9. The foreign object detection device includes an amplitude detector; the amplitude detector is configured to detect a target signal amplitude of the resonant current signal; and The controller is configured to determine whether a foreign object is present in the detection area corresponding to the first resonant network based on the target signal amplitude and the amplitude of the phase difference signal. The foreign object detection device according to any one of claims 1 to 7.

10. The controller: configured to determine an amplitude of the phase difference signal; configured to determine that a foreign object is present in the detection area corresponding to the first resonant network when it is determined that a quotient of the amplitude of the phase difference signal and the target signal amplitude is greater than or equal to a first preset threshold or less than or equal to a second preset threshold; or configured to determine that no foreign object is present in the detection area corresponding to the first resonant network when it is determined that the quotient of the amplitude of the phase difference signal and the target signal amplitude is greater than the second preset threshold and less than the first preset threshold. The foreign object detection device according to claim 9.

11. The controller: configured to determine an amplitude of the phase difference signal; configured to determine that a foreign object is present in the detection area corresponding to the first resonant network when it is determined that the target signal amplitude is greater than or equal to a third preset amplitude and a quotient of the amplitude of the phase difference signal and the target signal amplitude is greater than or equal to a first preset threshold or less than or equal to a second preset threshold; or and determining that no foreign object is present in the detection area corresponding to the first resonant network when it is determined that the target signal amplitude is smaller than the third preset amplitude, or when it is determined that the quotient of the amplitude of the phase difference signal and the target signal amplitude is greater than the second preset threshold and less than the first preset threshold. The foreign object detection device according to claim 9.

12. The foreign object detection device includes a signal generator, the signal generator comprising: configured to generate the preset carrier signal and the excitation signal according to a signal control command sent by the controller, where the frequencies of the preset carrier signal and the excitation signal are indicated by the signal control command; A foreign object detection device according to any one of claims 1 to 11.

13. the foreign object detection device includes a second resonant network and a switching module, the second resonant network and the first resonant network being separately connected to the switching module; and The switching module is configured to determine whether the excitation signal generated by the signal generator is transmitted to the first resonant network or the second resonant network based on a resonant network selection signal coming from the controller. The foreign object detection device according to claim 12.

14. A foreign object detection device as described in any one of claims 1 to 13, wherein the frequency of the predetermined carrier signal is the same as the frequency of the excitation signal.

15. A foreign object detection method applied to a foreign object detection device including a first resonant network, a signal coupler, a phase difference detector, and a controller, comprising: When the first resonant network is operating normally under the action of an excitation signal, the signal coupler couples a resonant current signal corresponding to the first resonant network with a preset carrier signal to obtain a coupled current signal; the phase difference detector extracting a low frequency signal component from the combined current signal and determining a phase difference signal based on the low frequency signal component, where the low frequency signal component is a signal component having a frequency less than or equal to a preset frequency in the combined current signal, and an amplitude of the phase difference signal indicative of a phase difference between the excitation signal and the resonant current signal; and determining whether a foreign object is present in a detection area corresponding to the first resonant network based on the amplitude of the phase difference signal; A method comprising:

16. the foreign object detection device includes a current detector; and The method comprises: When the first resonant network is operating normally under the action of the excitation signal, the current detector detects a current output by the first resonant network to obtain the resonant current signal. The method of claim 15 comprising:

17. the signal combiner includes a first inverter and a signal selector; and When the first resonant network is operating normally under the action of an excitation signal, the signal coupler couples a resonant current signal corresponding to the first resonant network with a preset carrier signal to obtain a coupled current signal, the first inverter performing a phase shift on the resonant current signal to obtain an anti-resonant current signal, where the phase difference between the anti-resonant current signal and the resonant current signal is 180 degrees; and the signal selector selecting, based on the preset carrier signal, the resonant current signal or the anti-resonant current signal as the combined current signal to be output; have 17. The method according to claim 15 or 16.

18. the signal selector includes a first switching transistor, a second switching transistor and a second inverter, the preset carrier signal is input to a first end of the first switching transistor through the second inverter, the preset carrier signal is also input to a first end of the second switching transistor, the resonant current signal is input to a second end of the first switching transistor, the anti-resonant current signal is input to a second end of the second switching transistor, and a third end of the first switching transistor is connected to a third end of the second switching transistor and functions as an output end of the signal selector; and The step of the signal selector selecting the resonant current signal or the anti-resonant current signal as the combined current signal to be output based on the preset carrier signal, controlling the first switching transistor to be turned on by a predetermined carrier signal input to a first end of the first switching transistor and flowing through the second inverter, and controlling the second switching transistor to be turned off by a predetermined carrier signal input to a first end of the second switching transistor, so that the resonant current signal is output as the combined current signal; or controlling the second switching transistor to be turned on by a preset carrier signal input to a first end of the second switching transistor and controlling the first switching transistor to be turned off by a preset carrier signal input to a first end of the first switching transistor and flowing through the second inverter, so that the anti-resonant current signal is output as the combined current signal. Including, 20. The method of claim 17.

19. the signal combiner includes a multiplier or an analog multiplication circuit; and When the first resonant network is operating normally under the action of an excitation signal, the signal coupler couples a resonant current signal corresponding to the first resonant network with a preset carrier signal to obtain a coupled current signal, the multiplier or the analog multiplication circuit multiplying the preset carrier signal by the resonant current signal to obtain the combined current signal. having 17. The method according to claim 15 or 16.

20. the foreign object detection device includes an amplitude detector; and The method comprises: said amplitude detector detecting a target signal amplitude of said resonant current signal.

20. The method of any one of claims 15 to 19, comprising:

21. The step of the controller determining whether a foreign object is present in a detection area corresponding to the first resonant network based on the phase difference signal includes: the controller determining an amplitude of the phase difference signal; and determining that a foreign object is present in the detection area corresponding to the first resonant network when the controller determines that a quotient of the amplitude of the phase difference signal and the target signal amplitude is greater than or equal to a first preset threshold or less than or equal to a second preset threshold; or determining that a foreign object is not present in the detection area corresponding to the first resonant network when the controller determines that a quotient of the amplitude of the phase difference signal and the target signal amplitude is greater than the second preset threshold and less than the first preset threshold. having 21. The method of claim 20.

22. The step of the controller determining whether a foreign object is present in a detection area corresponding to the first resonant network based on the phase difference signal includes: the controller determining an amplitude of the phase difference signal; and determining that a foreign object is present in the detection area corresponding to the first resonant network when the controller determines that the target signal amplitude is greater than or equal to a third preset amplitude and a quotient of the amplitude of the phase difference signal and the target signal amplitude is greater than or equal to a first preset threshold or less than or equal to a second preset threshold; or determining that no foreign object is present in the detection area corresponding to the first resonant network if the controller determines that the target signal amplitude is less than the third preset amplitude or if the controller determines that the quotient of the amplitude of the phase difference signal and the target signal amplitude is greater than the second preset threshold and less than the first preset threshold. having 21. The method of claim 20.

23. A computer program for causing a computer to carry out a method according to any one of claims 15 to 22.

24. A wireless charging transmitting end device comprising a power transmitting device and a foreign object detecting device according to any one of claims 1 to 14, The foreign object detection device is disposed on a side of the power transmitting device facing a wireless charging power receiving device, and the wireless charging power receiving device is included in a wireless charging receiving end device corresponding to the wireless charging transmitting end device. Wireless charging sending end device.

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