Foreign object detection device, method and wireless charging transmitter device

Abstract

A foreign body detection device comprises: a controller (30), a first resonant network (31), a signal coupler (32) and a phase difference detector (33), wherein the signal coupler (32) can obtain a resonant current signal corresponding to the first resonant network (31), and couple it with a preset carrier signal to obtain a coupled current signal, wherein the preset carrier signal has the same frequency as an excitation signal, and the phase difference detector (33) can extract a low-frequency signal component from the coupled current signal and determine a phase difference signal according to the low-frequency signal component, wherein the amplitude of the phase difference signal corresponds to the phase difference between the excitation signal and the resonant current signal, and the controller (30) can determine whether there is a foreign body in the detection area corresponding to the first resonant network (31) according to the amplitude of the phase difference signal. The foreign body detection device can reduce the cost of foreign body detection and improve the accuracy of foreign body detection. A foreign body detection method is also disclosed.

Description

Technical Field

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

[0002] With the continuous development of wireless charging technology, magnetic coupling wireless energy transmission technology has become a hot research direction of wireless charging technology because it is easy to achieve long-distance and high-power energy transmission. The magnetic coupling wireless charging system usually includes two separate devices, namely a wireless charging transmitter device and a wireless charging receiver device. Among them, the wireless charging transmitter device includes a power transmitter, and the wireless charging receiver device includes a power receiver. The power transmitter is connected to the power supply, and the power receiver is connected to the device to be charged (such as electric vehicles, mobile phones, etc.). The power transmitter and the power receiver transfer energy through electromagnetic induction between the transmitting coil and the receiving coil, thereby realizing wireless charging. Since there is a certain space gap between the power transmitter and the power receiver, during the charging process of the device to be charged, if there are foreign objects such as coins, tin foil (especially metal foreign objects) in the space gap, these foreign objects will produce eddy current effects under the action of the high-frequency electromagnetic field, thereby causing the temperature of these foreign objects to rise sharply, which may cause fire and other dangers. Therefore, when charging a device to be charged through a magnetic coupling wireless charging system, foreign object detection must be performed in order to ensure the safety of the wireless charging system and the device to be charged.

[0003] In the prior art, it is usually based on the change of electrical parameters caused by the change of physical characteristics of one or more foreign object detection coils set between the power transmitting device and the power receiving device to determine whether there is a foreign object. For example, the current or voltage of the foreign object detection coil is detected by an analog circuit, and the current or voltage of the foreign object detection coil is directly determined to determine whether there is a foreign object in the space gap. For another example, the current parameter or voltage parameter detected by the analog circuit can be transmitted to the controller, and the current parameter or voltage parameter is processed by the controller to obtain the corresponding phase angle or frequency parameter, and then the spatial gap is determined based on the phase angle or frequency parameter. However, the existing foreign object detection schemes generally have the problem of low detection accuracy or high system complexity, which leads to the low reliability and applicability of the existing foreign object detection schemes. Therefore, a foreign object detection scheme that is easy to implement and has high detection accuracy is urgently needed to be proposed. Summary of the invention

[0004] To solve the above problems, the present application provides a foreign object detection device, method and wireless charging transmitter device. The foreign object detection device and method provided by the present application can be used to simply and accurately detect foreign objects, reduce the cost of foreign object detection, and improve the accuracy of foreign object detection.

[0005] In the 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 can be used to obtain a resonant current signal when the first resonant network is working normally under the action of an excitation signal, couple a preset carrier signal and the resonant current signal to obtain a coupled current signal, and transmit the coupled current signal to the phase difference detector. Here, the preset carrier signal has the same frequency as the excitation signal, and the phase difference detector can be used to extract a low-frequency signal component in the coupled current signal, determine a phase difference signal based on the low-frequency signal component, and transmit the phase difference signal to the controller. Here, the low-frequency signal component is a signal component in the coupled current signal whose frequency is less than or equal to the first preset frequency, and the amplitude of the phase difference signal corresponds to the phase difference between the excitation signal and the resonant current signal. The controller can be used to determine whether there is a foreign object in the 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 can directly detect through the signal coupler and the phase difference detector to obtain a phase difference signal that can indicate the phase difference between the excitation signal of the first resonant network and its corresponding resonant current signal, and the controller performs a simple processing on the phase difference signal to determine whether there is a foreign object in the detection area corresponding to the first resonant network. On the one hand, the foreign object detection device provided by the present application directly detects through the signal coupler and the phase difference detector to obtain a phase difference signal that can indicate the phase difference between the excitation signal and the resonant current signal, and then performs a simple processing on the phase difference signal to achieve foreign object detection. Compared with the existing method of processing the current parameter or voltage parameter obtained by the analog circuit detection through the controller to obtain the phase angle or frequency parameter, and then further performing foreign object detection through the phase angle or frequency parameter, the complexity of the entire system is lower and the cost is also lower. On the other hand, the foreign object detection device provided by the present application determines whether there is a foreign object through the phase difference signal, which can avoid the problem of low detection accuracy caused by the current parameter or voltage parameter being easily disturbed by the main power in the method of directly performing foreign object detection based on the measured current parameter or voltage parameter. Therefore, the use of 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.

[0007] In combination with the first aspect, in a feasible implementation, the foreign object detection device further includes: a current detector. When the first resonant network works normally under the action of the excitation signal, the current detector can be used to detect the current output by the first resonant network to obtain the resonant current signal, and send the resonant current signal to the signal coupler.

[0008] In combination with the first aspect, in a feasible implementation, the signal coupler includes: a first inverter and a signal selector. The first inverter is used to phase shift the resonant current signal to obtain a reverse resonant current signal. Here, the phase difference between the reverse resonant current signal and the resonant current signal is 180 degrees. The signal selector can be used to select the resonant current signal or the reverse resonant current signal as a coupled current signal output according to the preset carrier signal.

[0009] In the above implementation, the coupling current signal is obtained by coupling through a first inverter and a signal selector which are simple in structure and widely used. On the one hand, the cost of the foreign object detection device can be reduced, and on the other hand, the structure of the foreign object detection device can be simplified, thereby improving the stability and robustness of the foreign object detection device.

[0010] In combination with the first aspect, in a feasible implementation, the signal selector includes: a first switch tube, a second switch tube and a second inverter. The first end of the first switch tube is connected to the preset carrier signal through the second inverter, the first end of the second switch tube is also connected to the preset carrier signal, the second end of the first switch tube is connected to the resonant current signal, the second end of the second switch tube is connected to the reverse resonant current signal, and the third end of the first switch tube is connected to the third end of the second switch tube and serves as the output end of the signal selector. The preset carrier signal can be used to control the first switch tube to be turned on through the second inverter, and to control the second switch tube to be turned off so that the resonant current signal is output as the coupled current signal. Alternatively, the preset carrier signal can be used to control the second switch tube to be turned on, and to control the first switch tube to be turned off so that the reverse resonant current signal is output as the coupled current signal.

[0011] In the above implementation, a switch tube and an inverter with a stable structure and low price are used to implement the signal selector, which can facilitate the integration of the signal selector and further reduce the implementation cost of the foreign matter detection device.

[0012] In combination with the first aspect, in a feasible implementation manner, the excitation signal is a sinusoidal 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 combination with the first aspect, in a feasible implementation, the signal coupler includes a multiplier or an analog multiplication circuit. The multiplier or the analog multiplication circuit is used to multiply the preset carrier signal and the resonant current signal to obtain the coupling current signal.

[0014] In the above implementation, the signal coupling of the preset carrier signal and the resonant current signal is achieved through a multiplier / analog multiplication circuit. The method is simple and easy to implement, and the efficiency of foreign object detection can be improved.

[0015] In combination with the first aspect, in a feasible implementation manner, the excitation signal and the preset carrier signal are sinusoidal signals.

[0016] In combination with the first aspect, in a feasible implementation, the controller may determine the 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, it is determined that there is a foreign object in the detection area corresponding to the first resonant network. Wherein, 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, it is determined that there is no foreign object in the detection area corresponding to the first resonant network.

[0017] In the above implementation, foreign object detection is performed directly by comparing the amplitude of the phase difference signal with the first preset amplitude and the second preset amplitude. The method is simple and easy to implement, which can reduce the requirements on the data processing capability of the controller and reduce the cost of foreign object detection.

[0018] In combination with the first aspect, in a feasible implementation, the foreign object detection device further includes an amplitude detector. The amplitude detector can be used to detect the target signal amplitude of the resonant current signal. The controller can be used to determine whether there is a foreign object in the detection area corresponding to the first resonant network according to the target signal amplitude and the amplitude of the phase difference signal.

[0019] In combination with the first aspect, in a feasible implementation, the controller can be specifically used to determine the amplitude of the phase difference signal. If it is determined that the divisor of the amplitude of the phase difference signal and the amplitude of the target signal is greater than or equal to a first preset threshold, or less than or equal to a second preset threshold, it is determined that there is a foreign object in the detection area corresponding to the first resonant network. If it is determined that the divisor of the amplitude of the phase difference signal and the amplitude of the target signal is greater than the second preset threshold and less than the first preset threshold, it is determined that there is no foreign object in the detection area corresponding to the first resonant network.

[0020] In the above implementation, since the amplitude of the phase difference signal and the divisor of the above target signal amplitude are only related to the phase difference between the excitation signal and the resonant current signal, the controller determines whether there is a foreign object in the detection area by the amplitude of the phase difference signal and the divisor of the above target signal amplitude. This can avoid the situation where the amplitude of the resonant current signal changes and it is impossible to accurately determine whether there is a foreign object in the detection area by directly using the amplitude of the phase difference signal, thereby improving the detection accuracy of the foreign object detection device.

[0021] In combination with the first aspect, in a feasible implementation, the controller can be specifically used to determine the amplitude of the phase difference signal. If it is determined that the target signal amplitude is greater than or equal to a third preset amplitude, and the divisor 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, it is determined that there is a foreign object 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 it is determined that the divisor 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, it is determined that there is no foreign object in the detection area corresponding to the first resonant network.

[0022] In the above implementation, since the amplitude of the phase difference signal is also related to the target signal amplitude of the resonant current signal, and the target signal amplitude is related to the volume of the object in the detection area (the object can be a foreign object or a non-foreign object, such as the body, chassis and other structures of an electric vehicle), in the above implementation, judgment is made from both the target signal amplitude and the divisor at the same time, which can avoid misjudging non-foreign structures (such as the body, chassis and other structures of an electric vehicle) as foreign objects, and can improve the detection accuracy of the foreign object detection device.

[0023] In combination with the first aspect, in a feasible implementation, the foreign object detection device further includes a signal generator, which can be used to generate the preset carrier signal and the excitation signal according to the signal control instruction sent by the controller. Here, the frequencies of the preset carrier signal and the excitation signal are indicated by the signal control instruction.

[0024] In combination with the first aspect, in a feasible implementation, the foreign object detection device further includes a second resonant network and a switching module, wherein the second resonant network and the first resonant network are respectively connected to the switching module. The switching module can be used to determine whether to transmit the excitation signal generated by the signal generator to the first resonant network or the second resonant network according to the resonant network selection signal from the controller.

[0025] In the 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, and the foreign object detection device includes a first resonant network, a signal coupler, a phase difference detector and a controller. The method includes: the signal coupler couples the resonant current signal of the first resonant network when it is working normally under the action of an excitation signal with a preset carrier signal to obtain a coupled current signal. The phase difference detector extracts the low-frequency signal component in the coupled current signal, and determines the phase difference signal based on the low-frequency signal component. Among them, the low-frequency signal component is a signal component in the modulated current signal whose frequency is less than or equal to the preset frequency. The signal amplitude of the phase difference signal is used to indicate the phase difference between the excitation signal and the resonant current signal. The controller determines whether there is a foreign object in the detection area corresponding to the first resonant network based on the phase difference signal.

[0026] In combination with the second aspect, in a feasible implementation, the foreign object detection device further includes: a current detector. The method further includes: when the first resonant network works normally under the action of the excitation signal, the current detector detects the current output by the first resonant network to obtain the resonant current signal.

[0027] In combination with the second aspect, in a feasible implementation, the signal coupler includes: a first inverter and a signal selector. The first inverter performs a phase shift on the resonant current signal to obtain a reverse resonant current signal. The reverse resonant current signal has a phase difference of 180 degrees with the resonant current signal. The signal selector selects the resonant current signal or the reverse resonant current signal as a coupled current signal output according to the preset carrier signal.

[0028] In combination with the second aspect, in a feasible implementation, the signal selector includes: a first switch tube, a second switch tube and a second inverter. The first end of the first switch tube is connected to the preset carrier signal through the second inverter, the first end of the second switch tube is also connected to the preset carrier signal, the second end of the first switch tube is connected to the resonant current signal, the second end of the second switch tube is connected to the reverse resonant current signal, and the third end of the first switch tube is connected to the third end of the second switch tube and serves as the output end of the signal selector. The preset carrier signal flowing through the second inverter connected to the first end of the first switch tube controls the first switch tube to turn on, and the preset carrier signal connected to the first end of the second switch tube controls the second switch tube to turn off, so that the resonant current signal is output as the coupling current signal. Alternatively, the preset carrier signal connected to the first end of the second switch tube controls the second switch tube to turn on, and the preset carrier signal flowing through the second inverter connected to the first end of the first switch tube controls the first switch tube to turn off, so that the reverse resonant current signal is output as the coupling current signal.

[0029] In combination with the second aspect, in a feasible implementation manner, the excitation signal is a sinusoidal 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 conjunction with the second aspect, in a feasible implementation, the signal coupler includes a multiplier or an analog multiplication circuit. The multiplier or the analog multiplication circuit multiplies the preset carrier signal and the resonant current signal to obtain the coupling current signal.

[0031] In combination with the second aspect, in a feasible implementation manner, the excitation signal and the preset carrier signal are sinusoidal signals.

[0032] In combination with the second aspect, in a feasible implementation, the controller may determine the 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, it is determined that there is a foreign object in the detection area corresponding to the first resonant network, wherein 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, it is determined that there is no foreign object in the detection area corresponding to the first resonant network.

[0033] In conjunction with the second aspect, in a feasible implementation, the foreign object detection device further includes an amplitude detector. The amplitude detector can detect and obtain a target signal amplitude of the resonant current signal.

[0034] In combination with the second aspect, in a feasible implementation, the controller may determine the amplitude of the phase difference signal. If the controller determines that the divisor of the amplitude of the phase difference signal and the amplitude of the target signal is greater than or equal to a first preset threshold, or less than or equal to a second preset threshold, it is determined that there is a foreign object in the detection area corresponding to the first resonant network. If the controller determines that the divisor of the amplitude of the phase difference signal and the amplitude of the target signal is greater than the second preset threshold and less than the first preset threshold, it is determined that there is no foreign object in the detection area corresponding to the first resonant network.

[0035] In combination with the second aspect, in a feasible 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 a third preset amplitude, and the divisor 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, it is determined that there is a foreign object 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 determines that the divisor of the amplitude of the phase difference signal and the peak value of the target signal is greater than the second preset threshold and less than the first preset threshold, it is determined that there is no foreign object in the detection area corresponding to the first resonant network.

[0036] In conjunction with the second aspect, in a feasible implementation, the foreign object detection device further includes a signal generator. The controller may generate a signal control instruction and send the signal control instruction to the signal generator. The signal generator may generate the preset carrier signal and the excitation signal according to the signal control instruction. Here, the frequencies of the preset carrier signal and the excitation signal are indicated by the signal control instruction.

[0037] In combination with the second aspect, in a feasible 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 respectively 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, based on the resonant network selection signal, whether to transmit the excitation signal generated by the signal generator to the first resonant network or the second resonant network.

[0038] In the third aspect, an embodiment of the present application provides a wireless charging transmitter device. The wireless charging transmitter device includes a power transmitting device and a foreign object detection device as provided in the first aspect above. Here, the foreign object detection device can be specifically arranged on the side of the power transmitting device facing the power receiving device for wireless charging. Among them, the power receiving device is included in the wireless charging receiving device corresponding to the wireless charging transmitter device. It should be noted that, in a specific implementation, the power transmitting device may include a power transmitting coil, the power receiving device may include a power receiving coil, and the foreign object detection device may be arranged on the side of the power transmitting coil facing the power receiving coil.

[0039] In a fourth aspect, an embodiment of the present application provides a wireless charging receiving device. The wireless charging receiving device includes a power receiving device and a foreign object detection device as provided in the first aspect above. Here, the foreign object detection device can be specifically arranged on the side of the power receiving device facing the power transmitting device of wireless charging. Among them, the power transmitting device can be included in the wireless charging transmitting device corresponding to the wireless charging receiving 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 arranged on the side of the power receiving coil facing the power transmitting coil. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a structural schematic diagram of a wireless charging system provided in an embodiment of the present application;

[0041] Figure 2 It is another structural schematic diagram of a wireless charging system provided in an embodiment of the present application;

[0042] Figure 3 It is a structural schematic diagram of a foreign body detection device provided in an embodiment of the present application;

[0043] Figure 4 It is another structural schematic diagram of a foreign body detection device provided in an embodiment of the present application;

[0044] Figure 5 It is another structural schematic diagram of a foreign body detection device provided in an embodiment of the present application;

[0045] Figure 6 It is a waveform change schematic diagram provided in an embodiment of the present application;

[0046] Figure 7 It is a signal coupling schematic diagram provided in an embodiment of the present application;

[0047] Figure 8 This is another signal coupling schematic diagram provided in an embodiment of the present application;

[0048] Fig. 9 It is another structural schematic diagram of a foreign body detection device provided in an embodiment of the present application;

[0049] Fig.10 is a schematic diagram of the structure of a signal coupler provided in an embodiment of the present application;

[0050] Fig.11 It is another structural schematic diagram of a foreign body detection device provided in an embodiment of the present application;

[0051] Fig.12 It is another structural schematic diagram of a foreign body detection device provided in an embodiment of the present application;

[0052] Fig.13 It is another structural schematic diagram of a foreign body detection device provided in an embodiment of the present application;

[0053] Fig.14 It is another structural schematic diagram of a foreign body detection device provided in an embodiment of the present application;

[0054] Fig.15 It is another structural schematic diagram of a foreign body detection device provided in an embodiment of the present application;

[0055] Fig.16 It is a flow chart of a foreign body detection method provided in an embodiment of the present application;

[0056] Fig.17 is a structural schematic diagram of another wireless charging system provided in an embodiment of the present application;

[0057] Fig.18 It is a structural schematic diagram of another wireless charging system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0058] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with a plurality of drawings provided in the embodiments of the present application.

[0059] The foreign object detection device and foreign object detection method provided in the present application are applicable to an electromagnetic coupling type wireless charging system. The electromagnetic coupling type wireless charging system can be a wireless charging system applied to electric vehicles, or a wireless charging system applied to mobile devices such as tablet computers and mobile phones, or a wireless charging system applied to intelligent robots or electric forklifts, etc. The specific application scenario can be determined according to the actual application scenario and is not limited here. For the convenience of description, the present application will take the wireless charging system applied to electric vehicles as an example to illustrate the foreign object detection device provided in the present application and the foreign object detection method based on the foreign object detection device.

[0060] With the increasing energy shortage and environmental pollution problems in modern society, electric vehicles, as new energy vehicles, have attracted widespread attention from all walks of life since their launch. An electric vehicle is a vehicle that uses an on-board power supply as its power source, uses an electric motor to drive the wheels, and complies with various requirements of road traffic and safety regulations. The battery charging methods of electric vehicles usually include: contact charging and wireless charging. Among them, contact charging uses the metal contact between the plug and the socket to conduct electricity, and wireless charging uses the coupled electromagnetic field as a medium to achieve the transmission of electrical energy. Compared with contact charging, wireless charging has the advantages of being easy to use, no sparks and electric shock hazards, no mechanical wear, adaptability to a variety of harsh environments and weather, and easy to achieve unmanned automatic charging and mobile charging. It may become the mainstream way of charging electric vehicles in the future. The following will take the wireless charging system used in electric vehicles as an example to illustrate the architecture of the wireless charging system applicable to the foreign object detection device provided in this application.

[0061] See also Figure 1 , Figure 1 1 is a schematic diagram of a wireless charging system provided in an embodiment of the present application. Figure 1 As shown, the wireless charging system may at least include: 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 charging process of the electric vehicle by the wireless charging system is completed by the wireless charging receiving device 1000 and the wireless charging transmitting device 1010 working together. Here, the wireless charging receiving device 1000 is the power receiving device in the wireless charging system, and the wireless charging transmitting device 1010 is the power transmitting device in the wireless charging system.

[0062] In some feasible implementations, the wireless charging station 101 may specifically be a fixed wireless charging station, a fixed wireless charging parking space, or a wireless charging road, etc., and this application does not impose any specific restrictions on this. The wireless charging receiving device 1000 may be specifically 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 can be charged by 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 together or may be separate. When separated, the rectifier circuit is usually placed inside the vehicle. Figure 1 The figure shows that the power receiving coil and the rectifier circuit are integrated together. The wireless charging transmitter 1010 can have a power transmitting coil and an inverter circuit. The power transmitting coil and the inverter circuit can also be integrated or separated. Figure 1 The figure shows the situation where the power transmitting coil and the inverter circuit are integrated together.

[0063] In some feasible implementations, contactless charging can be wireless energy transmission between the wireless charging receiving device 1000 and the wireless charging transmitting device 1010 through magnetic field coupling, which can be electromagnetic induction, magnetic resonance, etc., and this application does not impose specific restrictions on this. In practical applications, the electric vehicle 100 and the wireless charging station 101 can also charge bidirectionally, that is, the wireless charging station 101 can charge the electric vehicle 100, and the electric vehicle 100 can also charge the wireless charging station in reverse.

[0064] The following will be combined Figure 2 right Figure 1 The structures of the wireless charging transmitting device 1000 and the wireless charging receiving device 1010 in the wireless charging system are illustrated as examples. Figure 2 FIG. 1 is another structural diagram of a wireless charging system provided in an embodiment of the present application. Figure 2 As shown, the wireless charging system includes the above Figure 1 The wireless charging receiving device 1000 and the wireless charging transmitting device 1010 are shown.

[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. It can be understood here that the power transmitting module 1012 may be specifically a power transmitting coil (or simply a transmitting coil).

[0066] Optionally, the transmitting conversion module 1011 can be connected to the power supply of the wireless charging transmitting device 1010, and is used to convert the alternating current or direct current output by the power supply into high-frequency alternating current. Here, when the current output by the power supply is alternating current, the transmitting conversion module 1011 specifically includes a power factor correction unit, an inverter unit (or an inverter circuit) and a transmitter compensation network. When the current output by the power supply is direct current, the transmitting conversion module 1011 may specifically include an inverter unit and a transmitter compensation network. In actual use, the power factor correction unit can ensure that the input current phase of the wireless charging system is consistent with the grid voltage phase, reduce the system harmonic content, and increase the power factor value to reduce the pollution of the wireless charging system to the grid and improve reliability. The power factor correction unit can also be used to increase or decrease the output voltage of the power factor correction unit according to the requirements of the subsequent circuit in the actual application scenario. Optionally, when 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 can be added to the transmission conversion module 1011, and the DC conversion unit can be used to adjust the voltage output to the subsequent circuit so that the variable range of the voltage output to the subsequent circuit meets the requirements of the actual application scenario. The inverter unit can convert the voltage output by the power factor correction unit into a high-frequency AC voltage, and act on the power transmission module through the transmitter compensation network. The high-frequency AC voltage can greatly improve the transmission efficiency and transmission distance of the power transmission module. It should be noted here that the power supply of the wireless charging transmitter 1010 can be a power supply arranged inside the wireless charging transmitter 1010, or it can be an external power supply connected to the wireless charging transmitter 1010. This application does not impose specific restrictions on this.

[0067] The power transmitting module 1012 can be used to transmit the high-frequency alternating current provided by the transmitting conversion module 1011 through a magnetic field.

[0068] The transmission control module 1013 may be used to control the voltage, current and frequency conversion parameters of the transmission conversion module 1011 and the voltage and current of the high-frequency alternating current in the power transmission module 1012 according to the transmission power requirements of wireless charging in actual application scenarios.

[0069] The above-mentioned transmitting communication module 1014 can be used for wireless communication between the wireless charging transmitting device 1010 and the wireless charging receiving device 1000, including communication transmission of power control information, fault protection information, power on / off information, interactive authentication information and other information. On the one hand, the wireless charging transmitting device 1010 can receive the attribute information, charging request and interactive authentication information of the electric vehicle sent by the wireless charging receiving device 1000; on the other hand, the wireless charging transmitting device 1010 can also send wireless charging transmission control information, interactive authentication information, wireless charging history data information and the like to the wireless charging receiving device 1000. Specifically, the above-mentioned wireless communication method can include but is not limited to any one or more combinations of Bluetooth, wireless broadband (Wi-Fi), Zigbee, radio frequency identification technology (RFID), long range (Lora) wireless technology, and near field communication technology (NFC). Optionally, the transmitting communication module 1014 can also communicate with the smart terminal of the user of the electric vehicle, and the user can realize remote authentication and user information transmission through the communication function.

[0070] The authentication management module 1015 may be used for interactive authentication and authority management between the wireless charging transmitter 1010 and the electric vehicle in the wireless charging system.

[0071] The storage module 1016 can be used to store charging process data, interactive authentication data (such as interactive authentication information) and authority management data (such as authority management information) of the wireless charging transmitter 1010. The interactive authentication data and authority management data can be factory settings or user-set, which can be determined according to the actual application scenario and are not specifically limited here.

[0072] In a specific implementation, the wireless charging receiving device 1000 may specifically 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 can be understood that the power receiving module 1001 here can specifically be a power receiving coil (or simply a receiving coil). Optionally, the receiving conversion module 1002 can be connected to the energy storage module 1005 of the wireless charging receiving device 1000, and transmit the energy received to the energy storage module 1005. The energy storage module 1005 can be connected to the energy storage management module 1006, and the energy storage management module 1006 can be connected to the vehicle drive device of the electric vehicle for driving the electric vehicle. It should be noted here that the energy storage management module 1006 and the energy storage module 1005 can be located inside the wireless charging receiving device 1000, or outside the wireless charging receiving device 1000, and this application does not make specific restrictions.

[0073] The power receiving module 1001 can be used to receive active power and reactive power transmitted by the wireless charging transmitting device 1010. Here, the power receiving module 1001 can be a power receiving coil, and 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 of the power transmitting end and the compensation of the power receiving end in the wireless charging system provided in this application can be selectively combined at will. Common compensation network structure combinations include SS (series-series) type, PP (parallel-parallel) type, SP (series-parallel) type, PS (parallel-series) type, LCL-LCL (inductorcapacitorinductor-inductorcapacitor inductor) type, LCL-P (inductorcapacitor inductor-parallel) type, LCC-LCC (inductorcapacitor capacitor-inductorcapacitor capacitor) type and other structures, which can be determined according to the actual application scenario requirements, and this application does not limit this.

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

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

[0076] The receiving communication module 1004 can be used for wireless communication between the wireless charging receiving device 1000 and the wireless charging transmitting device 1010, including communication and transmission of power control information, fault protection information, power on / off information, interactive authentication information, etc. Specifically, 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 will not be described again here.

[0077] In such Figure 1 or Figure 2 In the wireless charging system shown, since there is a certain space gap between the wireless charging transmitter 1000 and the wireless charging receiver 1010, when the wireless charging system is charging the electric vehicle, if there are foreign objects such as coins and tin foil in the space gap, these foreign objects will produce eddy current effects under the action of the high-frequency electromagnetic field, causing the temperature of these foreign objects to rise sharply, which may cause fire and other dangers. Therefore, in order to ensure the safety of the wireless charging system and the device to be charged, foreign object detection must be performed.

[0078] In the prior art, it is usually based on the change of electrical parameters caused by the change of physical characteristics of one or more foreign object detection coils arranged between the power transmitting device and the power receiving device to determine whether there is a foreign object. For example, the current or voltage of the foreign object detection coil is detected by an analog circuit, and the current or voltage of the foreign object detection coil is directly determined to determine whether there is a foreign object in the space gap. For another example, the current parameter or voltage parameter detected by the analog circuit can be transmitted to the controller, and the current parameter or voltage parameter is processed by the controller to obtain the corresponding phase angle or frequency parameter, and then the phase angle or frequency parameter is used to determine whether there is a foreign object in the space gap. However, the existing foreign object detection schemes generally have the problem of low detection accuracy or high system complexity, which leads to the low reliability and applicability of the existing foreign object detection schemes.

[0079] Therefore, the technical problem that the present application needs to solve is: how to realize foreign body detection simply and accurately.

[0080] Embodiment 1

[0081] In order to solve the above problems, the present application provides a foreign body detection device, which is suitable for the above Figure 1 or Figure 2 In the wireless charging system shown in FIG. 1 , the foreign object detection device can be used to detect and determine the above Figure 1 or Figure 2 Whether there is foreign matter in the space between the wireless charging receiving device 1001 and the wireless charging transmitting device 1010 in the wireless charging system shown.

[0082] See below Figure 3 , Figure 3 Schematic diagram of a foreign body detection device provided in an embodiment of the present application. Figure 3 As shown, the foreign body 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, and the other end of the phase difference detector 33 is connected to one end of the signal coupler 32. The other end of the signal coupler 32 is connected to one end of the first resonant network 31.

[0083] In actual operation, the first resonant network 31 can receive an excitation signal (here assumed to be S1) and work normally under the action of the excitation signal S1. The signal coupler 32 can obtain the current signal corresponding to the first resonant network 31 working normally under the action of the excitation signal S1 (for the convenience of distinction, the following description will be replaced by the resonant current signal S2). It should be understood that the resonant current signal S2 indicates the magnitude of the current flowing through the first resonant network 31 when the first resonant network 31 works normally under the action of the excitation signal S1. The signal coupler 32 can also receive a preset carrier signal (here assumed to be S3), and couple the preset carrier signal S3 and the resonant current signal S2 to obtain a coupled current signal (here assumed to be S4). It should be noted that the preset carrier signal S3 and the excitation signal S2 need to ensure the same frequency. The preset carrier signal S3 can be a signal of any waveform and any reasonable signal amplitude, and the excitation signal S1 can also be a signal of any waveform and any reasonable signal amplitude. This application does not impose specific restrictions on this. The phase difference detector 33 can receive the coupled current signal S4 output by the signal coupler 32, extract the low-frequency signal component included in the coupled current signal S4, and determine the phase difference signal (here assumed to be S5) according to the low-frequency signal component. Here, the so-called low-frequency signal component is a signal component whose signal frequency contained in the coupled circuit signal S4 is less than or equal to the first preset frequency. Then, the phase difference detector 33 can transmit the phase difference signal S5 to the controller 30. Here, the amplitude of the phase difference signal S5 corresponds to the magnitude of the phase difference between the excitation signal S1 and the resonant current signal S2. Then, the controller 30 can determine whether there is a foreign object in the detection area corresponding to the first resonant network 31 according to the amplitude of the phase difference signal S5. It should be noted here that the detection area corresponding to the first resonant network 31 can be determined by the shape and size of the first resonant network 31. The controller 30 can be implemented in a frame-type componentized system, or in a system-on-chip composed of a single integrated chip, and this application does not make specific restrictions.

[0084] It can be seen from the working principle of the resonant network that when the physical properties of the components in the resonant network do not change, the output signal of the resonant network (specifically a current signal or a voltage signal, and this application will be described using a current signal as an example) and its excitation signal are theoretically completely overlapped, and the phase and amplitude are the same. When there are some foreign objects around the resonant network, these foreign objects may cause the physical properties of the components in the resonant network to change, so that the output signal of the resonant network will change in phase and amplitude relative to the excitation signal. Based on this principle, the foreign object detection device provided by the present application can directly detect through the signal coupler 32 and the phase difference detector 33 to obtain a phase difference signal S5 that can indicate the phase difference between the excitation signal S1 of the first resonant network 31 and its corresponding resonant current signal S2, and the controller 30 performs a simple processing on the phase difference signal S5 to determine whether there is a foreign object in the detection area corresponding to the first resonant network 31. On the one hand, the foreign body detection device provided by the present application directly detects the phase difference signal S5 that can indicate the phase difference between the excitation signal S1 and the resonant current signal S2 through the signal coupler 32 and the phase difference detector 33, and then performs a simple processing on the phase difference signal S5 to realize foreign body detection. Compared with the existing method of processing the current parameter or voltage parameter obtained by the analog circuit detection through the controller to obtain the phase angle or frequency parameter, and then further performing foreign body detection through the phase angle or frequency parameter, the complexity of the entire system is lower and the cost is also lower. On the other hand, the foreign body detection device provided by the present application determines whether there is a foreign body through the phase difference signal, which can avoid the problem of low detection accuracy caused by the current parameter or voltage parameter being easily disturbed by the main power in the method of directly performing foreign body detection based on the measured current parameter or voltage parameter. Therefore, the use of the foreign body detection device provided by the present application can reduce the cost of foreign body detection and improve the accuracy and reliability of foreign body detection.

[0085] For some possible implementations, see Figure 4 , Figure 4 is another structural schematic diagram of a foreign body detection device provided in an embodiment of the present application. Figure 4 As shown, the first resonant network 31 may specifically include a first port 310, a second port 311, a resonant capacitor C1, and an inductor L1. Among them, 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 L1, and the other end of the inductor L1 is connected to the first port 310. In actual operation, the second port 311 is used to receive an excitation signal S1 and transmit the excitation signal S1 to the resonant capacitor C1, the resonant capacitor C1 and the inductor L1 resonate, and the current flowing through the inductor L1 is finally output from the first port 310.

[0086] It should be noted here that Figure 4 The resonant capacitor C1 and the inductor L1 shown are connected in a series resonant manner, and this connection method is only exemplary. In actual implementation, the resonant capacitor C1 and the inductor L1 can also be connected in a parallel resonant manner, and this application does not impose specific restrictions on this. The above-mentioned inductor L1 can be an inductor of any shape and any number of turns. When a foreign object (especially a metal foreign object) approaches the inductor, the physical properties of the inductor itself (such as impedance characteristics, etc.) will change, which will cause the current and voltage flowing through the inductor to change. It should be noted that the capacitance of the resonant capacitor C1 can be determined by the impedance characteristics of the inductor L1, that is, the size of the resonant capacitor C1 needs to be matched and selected according to the impedance characteristics of the inductor L1.

[0087] It should also be noted that, through multiple tests on the first resonant network 31 provided in the present application, it is concluded that: in series resonance, the phase change between the excitation signal S1 and the resonant current signal S2 caused by foreign matter will be more obvious. Therefore, preferably, the above-mentioned resonant capacitor C1 and the inductor coil L1 are connected in a series resonance manner, which can improve the accuracy of foreign matter detection.

[0088] The embodiment of the present application also provides multiple possible specific implementations of the signal coupler 32 , and each of these possible specific implementations will be described in detail below.

[0089] Specific implementation method of signal coupler:

[0090] See also Figure 5 , Figure 5 is another structural schematic diagram of a foreign body detection device provided in an embodiment of the present application. Figure 5 As shown, the signal coupler 32 may specifically 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, another end of the signal selector 322 is connected to one end of the phase difference detector 33 through the fifth port 325, and another end of the signal selector 322 is connected to the first port of the first resonant network 31 through the third port 323.

[0091] In actual operation, the first inverter 321 can receive the resonant current signal S2 corresponding to the normal operation of the first resonant network 31 under the action of the excitation signal S1 through the third port 323, and then perform a 180-degree phase shift on the resonant current signal S2 to obtain a reverse resonant current signal corresponding to the resonant current signal (i.e., the phase difference between the reverse resonant current signal and the resonant current signal is 180 degrees, which is assumed to be S6 here), and transmit the reverse resonant current signal S6 to the signal selector 322. The signal selector 322 can also receive the above-mentioned preset carrier signal S3 through the fourth port 324, select the above-mentioned reverse resonant current signal S6 from the first inverter 321 or the resonant current signal S2 from the third port 323 as the coupling current signal S4 according to the above-mentioned preset carrier signal S3, and transmit the coupling current signal S4 to the phase difference detector 33 through the fifth port 325. Specifically, the signal selector 322 can select the resonant current signal S2 or the reverse resonant current signal S6 as the coupling current signal S4 and output it according to 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 the fourth preset amplitude, the resonant current signal S2 may be used as the coupling current signal S4 and output from 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 reverse resonant current signal S6 may be used as the coupling current signal S4 and output from the fifth port 325.

[0092] Preferably, the excitation signal S1 may be a sinusoidal 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.

[0093] The working principles of the first inverter 321 and the signal selector 322 will be exemplarily described below in conjunction with specific examples of the above-mentioned various signals.

[0094] Now assume that the excitation signal S1 is a sinusoidal signal A0*sin(ω0*t+θ0), that is, the excitation signal S1=A0*sin(ω0*t+θ0). Wherein, ω0 is the angular frequency of the excitation signal S1, θ0 is the initial phase of the excitation signal S1, and A0 is the initial amplitude of the excitation signal S1. Assume that the preset carrier signal S3 is Wherein, n is an integer, A2 is the maximum amplitude of the preset carrier signal S3, and A3 is the minimum amplitude of the preset carrier signal S3. It can be understood that, for the preset carrier signal S3, in the interval ((θ0+(2n-1)π, θ0+2nπ)), the amplitude of the preset carrier signal S3 is A2, and in the period (θ0+2nπ, θ0+(2n+1)π), the amplitude of the preset carrier signal S3 is A3. Here, the above-mentioned amplitude A2 is greater than the above-mentioned fourth preset amplitude, and the amplitude A3 is less than the above-mentioned fourth preset amplitude. Preferably, the above-mentioned A2=-A3, that is, the preset carrier signal S3 is a square wave. For the convenience of description, the following text will take the specific scenario in which the preset carrier signal S3 is a square wave signal, and the preset carrier signal S3 leads the excitation signal S1 by 90 degrees as an example to describe the preset carrier signal S3, that is, the preset carrier signal In addition, it is assumed that the resonant current signal S2 is A1*sin(ω0*t+θ0+Δθ). Based on the working characteristics of the first resonant network 31, it can be known that when the entire foreign object detection device has been calibrated and there is no foreign object in the detection area of ​​the first resonant network 31, the above resonant current signal S2 should completely overlap with the excitation signal S1, that is, Δθ=0, A1=A0. When there is a foreign object in the detection area of ​​the first resonant network 31, the impedance characteristics of the first resonant network 31 and the stray parameters of the line itself will change, resulting in a certain phase difference between the resonant current signal S2 and the excitation signal S1, and Δθ is not equal to 0 at this time. At the same time, the amplitude of the resonant current signal S2 will also become different from the amplitude of the excitation signal S1, that is, from the original A0 to the current A1. For example, please refer to Figure 6 , Figure 6 Schematic diagram of a waveform change provided by an embodiment of the present application. Figure 6 As shown, when there is a foreign object in the detection area of ​​the first resonant network 31, the resonant current signal S2 will have a certain phase shift relative to the excitation signal S1, and the amplitude will also change to a certain extent. It should be understood that Figure 6 The resonant current signal S2 shown in the figure has a positive phase shift relative to the excitation signal S1, and the amplitude becomes larger. In actual implementation, the resonant current signal S2 may also have a negative phase shift relative to the excitation signal S1, and the amplitude becomes smaller. Therefore, Figure 6 It is merely exemplary and not limiting.

[0095] In actual operation, the first inverter 321 will first perform a 180-degree phase shift on the received resonant current signal S2 to obtain the reverse resonant current signal S6, that is, the reverse resonant current signal S6 = -A1*sin(ω0*t+θ0+Δθ). Then, the signal selector 322 will select the resonant current signal S2 or the reverse current signal S6 as the coupled current signal S4 to output based on the preset carrier signal S3. For example, In this interval, the amplitude of the preset carrier signal S3 is A2, the signal selector 322 can determine that the amplitude of the preset carrier signal S3 is greater than the fourth preset amplitude, and the signal selector can output the resonant current signal S2 as the coupling current signal S4. In this interval, the amplitude of the preset carrier signal S3 is -A2, and the signal selector 322 can determine that the amplitude of the preset carrier signal S3 is less than the fourth preset amplitude, then the signal selector 322 can output the reverse resonant current signal S6 as the coupling current signal S4.

[0096] For example, see Figure 7 , Figure 7 Schematic diagram of signal coupling provided by an embodiment of the present application. Figure 7 As shown, when there is no foreign matter in the detection area, the resonant current signal S2 completely overlaps with the excitation signal S1, and the waveforms of the resonant current signal S2, the reverse resonant current signal S7 and the preset carrier signal S3 are as shown in FIG. Figure 7 After being coupled by the signal selector 322, the obtained coupling current signal S4 and the preset carrier signal S3 are as shown in FIG. Figure 7 Therefore, combining the expressions of the above-mentioned preset carrier signal S3, the resonant current signal S2, the reverse resonant current signal S6 and the working principle of the signal selector 322, it can be determined that when there is no foreign matter in the detection area, the above-mentioned coupling current signal S4 should satisfy the following relationship (1):

[0097]

[0098] For another example, see Figure 8 , Figure 8 This is another signal coupling schematic diagram provided by the 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 are different from those of the excitation signal S1. The waveforms of the resonant current signal S2, the reverse resonant current signal S7 and the preset carrier signal S3 are as follows: Figure 8 After being coupled by the signal selector 322, the obtained coupling current signal S4 and the preset carrier signal S3 are as shown in FIG. Figure 8Therefore, combining the expressions of the preset carrier signal S3, the resonant current signal S2, the reverse resonant current signal S6 and the working principle of the signal selector 322, it can be determined that when there is a foreign object in the detection area, the coupling current signal S4 should satisfy the following relationship (2):

[0099]

[0100] In the above implementation, the coupling current signal S4 is obtained by coupling through the first inverter 321 and the signal selector 322 which are simple in structure and widely used. On the one hand, the cost of the foreign object detection device can be reduced, and on the other hand, the structure of the foreign object detection device can be simplified, thereby improving the stability and robustness of the foreign object detection device.

[0101] Optional, see Fig. 9 , Fig. 9 is another structural schematic diagram of a foreign body detection device provided in an embodiment of the present application. Fig. 9 As shown, the signal coupler 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. In actual operation, the follower 326 is used to achieve phase following, so that the resonant current signal S2 does not change in phase during the transmission process between the third port 323 and the signal selector 322. Through the follower 326, the phase change of the resonant current signal S2 due to interference in the line transmission process can be avoided, thereby ensuring that a more accurate phase difference can be detected later.

[0102] For further information, see Fig.10 , Fig.10 Schematic diagram of the structure of the signal coupler provided in the embodiment of the present application. Fig.10As shown, the signal selector 322 in the signal coupler 32 may specifically include a first switch tube 3221, a second switch tube 3222 and a second inverter 3223. Among them, the first end of the first switch tube 3222 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. The first end of the second switch tube 3222 is connected to the fourth port 324. The second end of the first switch tube 3221 is connected to the third port 323 through the follower 326, and the second end of the second switch tube 3222 is connected to the third port 323 through the first inverter 321. The third end of the first switch tube 3221 and the third end of the second switch tube 3222 are simultaneously connected to the fifth port 325. In other words, the first end of the first switch tube 3221 is connected to the preset carrier signal through the second inverter 3223, and the first end of the second switch tube 3222 is also connected to the preset carrier signal. The second end of the first switch tube 3221 is connected to the resonant current signal, and the second end of the second switch tube 3222 is connected to the reverse resonant current signal. The third end of the first switch tube 3221 is connected to the third end of the second switch tube 3221 and serves as the output end of the signal selector 322. In this implementation, a switch tube and an inverter with a stable structure and low price are used to implement the signal selector 322, which can facilitate the integration of the signal selector 322 and further reduce the implementation cost of the foreign body detection device.

[0103] In actual operation, in certain time periods, the preset carrier signal S3 can turn on the first switch tube 3221 through the second inverter 3223, and the preset carrier signal S3 can also turn off the second switch tube 3222, so that the resonant current signal S2 can be output from the fifth port 325 as the coupling current signal S4. In other time periods, the preset carrier signal S3 can turn off the first switch tube 3221 through the second inverter 3223, and the preset carrier signal S3 can also turn on the second switch tube 3222, so that the reverse resonant current signal S7 can be output from the fifth port 325 as the coupling current signal S4. It should be noted that in order to enable the first switch tube 3221 and the second switch tube 3222 to switch between the two switching states of on and off under the control of the preset carrier signal S2, the signal amplitude A2 of the preset carrier signal S3 should be equal to or greater than the on voltage of the first switch tube 3221 and the second switch tube 3222. It should be understood that the on-voltages of the first switch tube 3221 and the second switch tube 3222 may be the same or different. For the convenience of description, the following description will take the scenario where the on-voltages of the first switch tube 3221 and the second switch tube 3222 are equal to the fourth preset amplitude as an example.

[0104] The following will be combined Fig.10The structure shown in the figure and the description of the preset carrier signal S3 in the previous text are used as an example to illustrate the working principle of the above signal selector 322. Here, it is assumed that the above third preset amplitude is A4, and A2 is greater than A4. As described above, the preset carrier signal exist In the corresponding period, the signal amplitude of the preset carrier signal S3 is A2. In this case, the input voltage of the gate of the second switch tube 3222 is A2, which is greater than the conduction voltage of the second switch tube 3222, so the second switch tube 3222 is in the conduction state. At the same time, the preset carrier signal S3 is phase-shifted by 180 degrees through the second inverter 3223, and its signal amplitude is changed to -A2, that is, the input voltage of the gate of the first switch tube 3221 is -A A This voltage is smaller than the on-state voltage of the first switch tube 3221, so the first switch tube 3221 is in the off state. During the corresponding period, the reverse resonant current signal S6 is output from the fifth port 325 as the coupling current signal S4 .

[0105] Similarly, in In the corresponding time period, the signal amplitude of the preset carrier signal S3 is -A2. In this case, the input voltage of the gate of the second switch tube 3222 is -A2, which is less than the conduction voltage of the second switch tube 3222, so the second switch tube 3222 is in the cut-off state. At this time, the preset carrier signal S3 is 180 degrees phase-shifted by the second inverter 3223, and its signal amplitude is changed to A2, that is, the input voltage of the gate of the first switch tube 3221 is A2. This voltage is greater than the conduction voltage of the first switch tube 3221, so the first switch tube 3221 is in the conduction state, so that During the corresponding period, the resonant current signal S2 is output from the fifth port 325 as a coupled current signal S4 .

[0106] It should be noted here that Fig.10 The first switch tube 3221 and the second switch tube 3222 shown in the figure are metal oxide semiconductor field effect transistors (metal semiconductor field effect transistor, MOSFET, hereinafter referred to as MOS tube). Fig.10This is only for illustrative purposes. In practical applications, the switch tubes involved in the embodiments of the present application (such as the first switch tube 3221 and the second switch tube 3222 mentioned above) can also be of other types. For example, the switch tubes involved in the present application can also be insulated bipolar transistors (IGBT), SiC MOSFET (silicon carbide metal oxide semiconductor, silicon carbide field effect transistor), etc., and the present application does not impose specific restrictions on this. When the first switch tube 3221 and the second switch tube 3222 are IGBT tubes, the first end of the first switch tube 3221 and the second switch tube 3222 is the base, the second end of the first switch tube 3221 and the second switch tube 3222 is the collector, and the third end of the first switch tube 3221 and the second switch tube 3222 is the emitter. When the first switch tube 3221 and the second switch tube 3222 are MOS tubes, the first ends of the first switch tube 3221 and the second switch tube 3222 are gates, the second ends of the first switch tube 3221 and the second switch tube 3222 are drains, and the third ends of the first switch tube 3221 and the second switch tube 3222 are sources.

[0107] It should also be noted that the inverter involved in the specific implementation method 1 (such as the first inverter 321 and the second inverter 3223) can be a device or circuit that can perform a 180-degree phase shift on the input signal in various implementation forms, such as a typical complementary metal oxide semiconductor (CMOS) inverter, a transistor-transistor logic (TTL) NAND gate circuit, etc., and this application does not impose specific restrictions on this.

[0108] Specific implementation method 2 of the signal coupler:

[0109] See also Fig.11 , Fig.11 is another structural schematic diagram of a foreign body detection device provided in an embodiment of the present application. Fig.11 As shown, the signal coupler 32 may specifically include a multiplier / analog multiplication circuit 326, a third port 323, a fourth port 324, and a fifth port 325. The 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, the second end of the multiplier / analog multiplication circuit 326 is connected to the fourth port 324, and the 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.

[0110] In actual operation, the multiplier / analog multiplication circuit 326 can be used to multiply the resonant current signal S2 received through the third port 323 (it should be explained here that the description of each signal in the specific implementation method 1 will continue to be quoted in the specific implementation method 2) and the preset carrier signal S3 received through the fourth port 324 to obtain the coupling current signal S4. It should be noted that in this implementation, the preset carrier signal S3 and the excitation signal S1 can be sinusoidal signals with the same frequency.

[0111] For example, assuming that the preset carrier signal S3 is a sinusoidal signal (Here it is assumed that there is a 90-degree phase difference between the preset carrier signal S3 and the excitation signal S1), the excitation signal S1 is a sinusoidal signal A0*sin(ω0*t+θ0), and the resonant current signal S2 is A1*sin(ω0*t+θ0+Δθ). It can be seen from the above content that when the entire foreign object detection device has been calibrated and there is no foreign object in the detection area of ​​the first resonant network 31, the above resonant current signal S2 should completely overlap with the excitation signal S1, that is, Δθ=0, A1=A0. When there is a foreign object in the detection area of ​​the first resonant network 31, Δθ is not equal to 0, and the amplitude of the resonant current signal S2 will also change from A0 to A1. After receiving the above preset carrier signal S1 and the resonant current signal S2, the above multiplier / analog multiplication circuit 326 can multiply the above preset carrier signal S1 and the resonant current signal S2 to obtain a coupled current signal S4. Here, the coupled current signal S4 satisfies the following relationship (3):

[0112]

[0113] It should be noted here that the above-mentioned multiplier / analog multiplication circuit 326 can specifically be a device or circuit in various implementation forms that can multiply the input signal. This application does not limit the specific implementation form of the multiplier / analog multiplication circuit 326.

[0114] In the above implementation, the signal coupling of the preset carrier signal S1 and the resonant current signal S2 is achieved through a multiplier / analog multiplication circuit. The method is simple and easy to implement, and the efficiency of foreign object detection can be improved.

[0115] For further information, please see Figure 5After coupling the coupling current signal S4, the signal coupler 32 can transmit the coupling current signal S4 to the phase difference detector 33. After receiving the coupling current signal S4, the phase difference detector 33 can filter the coupling current signal S4 to extract the low-frequency signal component of the coupling current signal S4 whose frequency is less than or equal to the first preset frequency. Then, the phase difference detector 33 can determine the phase difference signal S5 according to the low-frequency signal component and send the phase difference signal S5 to the controller 30.

[0116] The following will combine the contents of the specific implementation method 1 and the specific implementation method 2 of the signal coupler in the previous text to explain in detail the principle of the phase difference detector 33 detecting and obtaining the phase difference signal S5. As mentioned above, in the specific implementation method 1 of the signal coupler, when there is no foreign matter in the detection area, the coupling current signal S4 satisfies the above formula (1), and when there is a foreign matter in the detection area, the coupling current signal S4 satisfies the above formula (2). According to the above formula (1) or formula (2), the above coupling current signal S4 is equivalent to the resonant current signal S2 multiplied by a rectangular wave signal with an amplitude of (1, -1) and a frequency the same as the frequency of the resonant current signal S2. Based on the signal processing principle, it can be known that the fundamental wave of the above rectangular wave signal is a sine wave. Therefore, the process of coupling the preset carrier signal S3 with the resonant current signal S2 to obtain the coupling current signal S4 described in the specific implementation method 1 of the signal coupler 32 is essentially equivalent to the process of multiplying a sine signal with the same frequency as the resonant current signal S2 by the resonant current signal S2. Now assume that the fundamental wave of the matrix wave signal (here assumed to be S7) is The resonant current signal S2 is A1*sin(ω0*t+θ0+Δθ), and the coupled current signal S4 is equivalent to the signal Similarly, the signal coupling process described in the second specific implementation method of the signal coupler in the previous article is also finally obtained. This coupling current signal. When the coupling current signal S4 is When This low-frequency signal component and The phase difference detector 33 can detect the high frequency signal component contained in the coupling current signal S4. This high-frequency signal component is filtered out, and the coupled current signal S4 can be obtained. Then, the phase difference detector 33 can convert This low-frequency signal component is determined as a phase difference signal S5 and the phase difference signal S5 is sent to the controller 30 .

[0117] Optionally, the low frequency signal component It can be seen that when Δθ is less than 0 (i.e., the phase of the resonant current signal S2 lags behind the initial phase of the excitation signal S1), the amplitude of the low-frequency signal component is a negative voltage. In the case where the controller 30 does not have the ability to collect negative voltages, the phase difference detector 33 is also used to obtain a positive DC signal (here, it is assumed that the amplitude of the DC signal is C), and couple the DC signal to the low-frequency signal component. The low-frequency signal component after level conversion can be obtained The low-frequency signal component after level conversion The amplitude of is a positive voltage. Then, the phase difference detector 33 can convert the low-frequency signal component after level conversion Determined as the phase difference signal S5.

[0118] It should be noted that, in practical applications, the phase difference detector 33 may be a device or circuit in various implementation forms that can filter out high-frequency signal components in the coupling current signal S4, such as a commonly used inductor filter, capacitor filter, L-type filter, etc. The present application does not limit the specific implementation form of the phase difference detector 33.

[0119] Furthermore, the present application also provides a variety of implementations of the controller 30 determining whether there is a foreign object in the detection area according to the phase difference signal S5. The following will describe in detail the various possible specific implementations. Here, the phase difference signal S5 is or When the controller 30 determines whether there is a foreign object in the detection area, the process is the same. Therefore, the phase difference signal S5 will be used as the This scenario is used as an example to describe the process by which the controller 30 determines whether there is a foreign object in the detection area.

[0120] Judgment method 1:

[0121] After acquiring the phase difference signal S5, the controller 30 may first determine the amplitude of the phase difference signal S5. Here, in combination with the above example, the amplitude of the phase difference signal S5 is Then, the controller 30 may determine whether the amplitude of the phase difference signal S5 is less than the first preset amplitude and greater than the second preset amplitude. If the controller 30 determines that the detection area corresponding to the first resonant network 31 is free of foreign matter, the detection area corresponding to the first resonant network 31 is free of foreign matter. If the amplitude is greater than or equal to the first preset amplitude, or less than or equal to the second preset amplitude, it can be determined that there is a foreign object in the detection area corresponding to the first resonant network 31.

[0122] In the above implementation, foreign object detection is performed directly by comparing the amplitude of the phase difference signal S5 with the first preset amplitude and the second preset amplitude. The method is simple and easy to implement, which can reduce the requirements on the data processing capability of the controller 30 and reduce the cost of foreign object detection.

[0123] Judgment method 2:

[0124] See also Fig.12 , Fig.12 is another structural schematic diagram of a foreign body detection device provided in an embodiment of the present application. Fig.12 As shown, the foreign body detection device may also 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. In actual operation, the amplitude detector 34 can receive the coupling current signal S4 from the signal coupler 32, detect the signal amplitude of the coupling current signal S4 (for ease of understanding, the target signal amplitude will be used instead of the description below), and transmit the target signal amplitude to the controller 30. It should be noted here that the above-mentioned amplitude detector 34 can be a device or circuit capable of detecting the amplitude of the current signal in various implementation forms, and the present application does not limit the specific implementation form of the amplitude detector 34.

[0125] Further, the controller 30 can determine whether there is a foreign object in the detection area corresponding to the first resonant network 31 according to the amplitude of the target signal and the amplitude of the phase difference signal S5. Combined with the content described above, it can be seen that the amplitude of the phase difference signal S5 is related to the phase difference between the excitation signal S1 and the resonant current signal S2 (i.e., Δθ in the previous text) and the amplitude of the resonant current signal S2 (i.e., A1 in the previous text). Therefore, here, the amplitude of the resonant current signal S2 and the amplitude of the phase difference signal S5 are used together to determine whether there is a foreign object in the detection area, which can improve the credibility of the judgment result and improve the detection accuracy of the foreign object detection device.

[0126] In a first optional specific implementation, after determining the amplitude of the phase difference signal S5, the controller 30 can calculate the divisor (for the convenience of description, it is assumed to be R1 here) between the amplitude of the phase difference signal S5 and the amplitude of the target signal. Then, if the controller 30 determines that the divisor R1 is greater than the second preset threshold and less than the first preset threshold, it can be determined that there is no foreign matter in the detection area corresponding to the first resonant network 31. If the controller 30 determines that the divisor R1 is less than or equal to the second preset threshold, or greater than or equal to the first preset threshold, it can be determined that there is a foreign matter in the detection area corresponding to the first resonant network 31. For example, in combination with the above example, the phase difference signal S5 is The resonant current signal S2 is A1*sin(ω0*t+θ0+Δθ), that is, the target signal amplitude is A1, then the controller 30 can calculate the divisor R1 as Then, if the controller 30 determines If the value is greater than the second preset threshold and less than the first preset threshold, it can be determined that there is no foreign object in the detection area corresponding to the first resonant network 31. If the value is less than or equal to the second preset threshold, or greater than or equal to the first preset threshold, it can be determined that there is a foreign object in the detection area corresponding to the first resonant network 31.

[0127] Here, since the amplitude of the phase difference signal S5 and the divisor R1 of the above-mentioned target signal amplitude are only related to the phase difference between the excitation signal S1 and the resonant current signal S2, the controller 30 determines whether there is a foreign object in the detection area by the amplitude of the phase difference signal S5 and the divisor R1 of the above-mentioned target signal amplitude. This can avoid the situation where the amplitude of the resonant current signal S2 changes and the amplitude cannot accurately determine whether there is a foreign object in the detection area, thereby improving the detection accuracy of the foreign object detection device.

[0128] In a second optional specific implementation, after determining the target signal amplitude and the amplitude of the phase difference signal S5, the controller 30 can determine the divisor (also assumed to be R1 here) 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 determines that the divisor R1 is greater than or equal to the first preset threshold, or is less than or equal to the second preset threshold, it is determined that there is a foreign object 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 determines that the divisor R1 is greater than the second preset threshold and less than the first preset threshold, it is determined that there is no foreign object in the detection area corresponding to the first resonant network 31.

[0129] Here, since the amplitude of the phase difference signal S5 is also related to the target signal amplitude of the resonant current signal S2, and the target signal amplitude is related to the volume of the object in the detection area (the object can be a foreign object or a non-foreign object, such as the body, chassis and other structures of an electric vehicle), in the above implementation, judgment is made from both the target signal amplitude and the divisor R1. This can avoid misjudging non-foreign structures (such as the body, chassis and other structures of an electric vehicle) as foreign objects, and can improve the detection accuracy of the foreign object detection device.

[0130] For some alternative implementations, see Fig.13 , Fig.13is another structural schematic diagram of a foreign body detection device provided in an embodiment of the present application. Fig.13 As shown, the foreign body 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. That is, 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 another end of the signal generator 35 is connected to one end of the signal coupler 32.

[0131] In actual operation, the controller 30 may generate a signal control instruction corresponding to the first resonant network 31, and the signal control instruction may be used to indicate the signal frequency of the excitation signal S1 and the preset carrier signal (here, it is assumed that the signal frequency of the excitation signal S1 and the preset carrier signal S3 is f1). Then, the controller 30 may send the signal control instruction to the signal generator 35. After receiving the signal control instruction, the signal generator 35 may generate the excitation signal S1 and the preset carrier signal S3 with a frequency of f1.

[0132] It should be noted that the signal waveform and / or signal amplitude of the above-mentioned excitation signal S1 and the preset carrier signal S3 can be pre-configured by the signal generator 35, or can be indicated in real time by the controller 30 through the above-mentioned signal control instructions, and this application does not impose specific restrictions on this.

[0133] In practical applications, the signal generator 35 may be a device or circuit in various implementation forms that can generate signals of different frequencies, different waveforms, and different amplitudes. The present application does not limit the specific implementation form of the signal generator 35.

[0134] For some alternative implementations, see Fig.14 , Fig.14 is another structural schematic diagram of a foreign body detection device provided in an embodiment of the present application. Fig.14 As shown, the foreign body 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 respectively. The switching module 36 may be used to determine whether to transmit the excitation signal S1 generated by the signal generator 35 to the first resonant network 31 or the second resonant network 37 according to the resonant network selection signal from the controller 30. In other words, the switching module 36 may be used to select the first resonant network 31 or the second resonant network 37 for foreign body detection according to the resonant network selection signal from the controller 30, thereby realizing detection of different detection areas.

[0135] What needs to be understood here is that Fig.14Only the first resonant network 31 and the second resonant network 37 are shown in the figure. In actual implementation, the foreign object detection device may also include other resonant networks in addition to the first resonant network 31 and the second resonant network 37. The switching module 36 may be used to select different resonant networks for foreign object detection according to the instruction of the controller 30. Since the connection mode and working principle of the other resonant networks in addition to the first resonant network 31 and the second resonant network 37 are similar to those of the second resonant network 37, the following will be used to avoid repetition. Fig.14 The structure shown is described as an example.

[0136] It should also be noted here that the second resonant network 37 and the first resonant network 31 may be identical in structure (i.e., the resonant capacitors and coils included are the same) but have different installation positions in the foreign object detection device (i.e., the corresponding detection areas are different). Alternatively, the second resonant network 37 and the first resonant network 31 may also be different in structure (i.e., the resonant capacitors and coils included are different), and have different installation positions in the foreign object detection device (i.e., the corresponding detection areas are different). Based on the working characteristics of the resonant network, it can be known that the frequency of the excitation signal of the resonant network should be the same as the resonant frequency of the resonant network itself in order to resonate, so the frequencies of the excitation signals required by resonant networks with different structures will also be different. In other words, 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, the function of the switching module 36 will be described in detail below, taking the specific scenario in which the second resonant network 37 and the first resonant network 31 have different structures and installation positions as an example.

[0137] In actual operation, the controller 30 may determine whether to detect foreign objects through the first resonant network 31 or the second resonant network 37. Optionally, the controller 30 may determine whether to detect foreign objects through the first resonant network 31 or the second resonant network 32 according to the user instruction it receives. Alternatively, the controller 30 may also determine whether to detect foreign objects through the first resonant network 31 or the second resonant network 32 according to its preset trigger mechanism. For example, the trigger mechanism may specifically be: foreign object detection is performed through the first resonant network 31 at time t1, and foreign object detection is performed through the second resonant network 37 at time t2. When the controller 30 determines to perform foreign body detection through the first resonant network 31, the controller 30 may generate a signal control instruction (for the sake of distinction, the first signal control instruction will be used to replace the description below) and send the first signal control instruction to the signal generator 35. The signal generator 35 may generate an excitation signal S1 with a frequency of f1 and a preset carrier signal S3 according to the first signal control instruction, send the excitation signal S1 with a frequency of f1 to the switching module 36, and send the preset carrier signal S3 with a frequency of f1 to the signal coupler 32. At the same time, the controller 30 may also generate a resonant network selection signal (for the sake of distinction, the first resonant network selection signal will be used to replace the description below) 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 received excitation signal with a frequency of f1 to the first resonant network 31. When the controller 30 determines to perform foreign body detection through the second resonant network 37, the controller 30 may generate a signal control instruction (for the sake of distinction, the second signal control instruction will be used to replace the description below, and it is assumed that the signal frequency indicated by the second signal control instruction is f2) and send the second signal control instruction to the signal generator 35. The signal generator 35 may generate an excitation signal S1 with a frequency of f2 and a preset carrier signal S3 according to the second signal control instruction, send the excitation signal S1 with a frequency of f2 to the switching module 36, and send the preset carrier signal S3 with a frequency of f2 to the signal coupler 32. At the same time, the controller 30 may also generate a resonant network selection signal (for the sake of distinction, the second resonant network selection signal will be used to replace the description below) 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 with a frequency of f2 received by it to the second resonant network 37.

[0138] It should be noted that, in actual implementation, the switching module 36 can be a multi-way selection switch device or circuit in various implementation forms. Specifically, the switching module 36 can be a discrete switch device or an integrated analog switch chip, etc. The present application does not limit the specific implementation form of the switching module 36.

[0139] For some alternative implementations, see Fig.15 , Fig.15 is another structural schematic diagram of a foreign body detection device provided in an embodiment of the present application. Fig.15 As shown, the foreign body detection device may further include a current detector 38. The first resonant network 31 is connected to the signal coupler 32 via the current detector 38. It should be noted that: Fig.15 The structure shown also applies to the previous Fig.14 In the structure shown here, the second resonant network 37 and the switching module 36 are not shown for the sake of simplifying the description.

[0140] In actual operation, when the first resonant network 31 works normally under the action of the excitation signal S1, the current detector 38 can be used to detect the current flowing through the first resonant network 31, and amplify the current to convert it into the above-mentioned resonant current signal S2.

[0141] It should be noted that, in actual implementation, the current detector 38 may be a device or circuit capable of realizing current detection in various implementation forms, and the present application does not limit the specific implementation form of the current detector 38 .

[0142] It should also be noted that the above-mentioned preset parameters such as the first preset amplitude, the second preset amplitude, the third preset amplitude, the first preset threshold, the second preset threshold, etc. can specifically be empirical values ​​obtained from multiple foreign object detection tests on the foreign object detection device provided in this application.

[0143] It should also be noted that the above-mentioned controller 30 can be a device that can perform calculations and issue control instructions in various implementation forms, 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 other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The present application does not specifically limit the implementation form of the controller 30.

[0144] The foreign body detection device provided by the present application can directly detect the phase difference signal S6 that can indicate the phase difference between the excitation signal S1 input by the first resonant network 31 and the resonant current signal S2 output by the first resonant network 31 through the signal coupler 32 and the phase difference detector 33, and simply process the phase difference signal S6 through the controller 30 to determine whether there is a foreign body in the detection area corresponding to the first resonant network. On the one hand, the foreign body detection device provided by the present application directly detects the phase difference signal S5 that can indicate the phase difference between the excitation signal S1 and the resonant current signal S2 through the signal coupler 32 and the phase difference detector 33, and provides it to the controller 30 for further simple processing to realize foreign body detection. Compared with the existing method of processing the current parameter or voltage parameter obtained by the analog circuit detection by the controller to obtain the phase angle or frequency parameter, the complexity of the whole system is lower and the cost is also lower. On the other hand, the foreign body detection device provided by the present application determines whether there is a foreign body through the phase difference signal, which can avoid the problem of low detection accuracy caused by the current parameter or voltage parameter being easily disturbed by the main power in the method of directly performing foreign body detection based on the measured current parameter or voltage parameter. Therefore, the use of 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.

[0145] Embodiment 2

[0146] See also Fig.16 , Fig.16 1 is a flow chart of a foreign body detection method provided in an embodiment of the present application. The foreign body detection method is applicable to the foreign body detection device described in the first embodiment. Here, the specific structure of the foreign body detection device and the functions of each structure are as described in the first embodiment, and the description of various types of signals involved in the execution process of the foreign body detection method is also as described in the first embodiment. Fig.16 As shown, the method comprises the steps of:

[0147] S101, a signal coupler couples a resonant current signal of a first resonant network when it works normally under the action of an excitation signal with a preset carrier signal to obtain a coupled current signal.

[0148] In some feasible implementations, after the modules in the foreign object detection device are correctly connected and calibrated, the controller 30 can control the excitation signal S1 to be input to the first resonant network 31 so that the first resonant network 31 can work normally under the action of the excitation signal S1. Here, the process of the first resonant network 31 working normally under the action of the excitation signal S1 can refer to the process of the first resonant network 31 working normally under the action of the excitation signal S1 described in Example 1, which will not be repeated here. 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 can couple the resonant current signal S2 and the preset carrier signal S3 to obtain a coupled current signal S4. Then, the signal coupler 32 can transmit the coupled current signal S4 to the phase difference detector 33.

[0149] In an optional implementation, the signal coupler 32 specifically includes a first inverter 321 and a signal selector 322. The first inverter 321 can perform a 180-degree phase shift on the received resonant current signal S2 to obtain a reverse resonant current signal S6. For the specific process, please refer to the process described in Embodiment 1 in which the first inverter 321 performs a 180-degree phase shift on the received resonant current signal S2 to obtain a reverse resonant current signal S6, which will not be repeated here. Then, the signal selector 322 can select the resonant current signal S2 or the reverse resonant current signal S6 as the coupling current signal according to the preset carrier signal.

[0150] Further, the signal selector 322 may specifically include a first switch tube 3221, a second switch tube 3222 and a second inverter 3223. In actual operation, in certain time periods, the signal selector 322 may control the first switch tube 3221 to be turned on by a preset carrier signal S3 flowing through the second inverter 3223, and at the same time control the second switch tube 3222 to be turned off by the preset carrier signal, so that the resonant current signal S2 is output as the coupling current signal S4. Alternatively, the signal selector may control the second switch tube 3222 to be turned on by the preset carrier signal S3, and control the first switch tube 3221 to be turned off by the preset carrier signal S3 flowing through the second inverter 3223, so that the reverse resonant current signal S6 is output as the coupling current signal. Here, the specific working process of the first switch tube 3221, the second switch tube 3222 and the second inverter 3223 can refer to the corresponding content described in the first embodiment, and will not be repeated here.

[0151] Optionally, in the above implementation, the excitation signal S1 may be a sinusoidal 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.

[0152] In another optional implementation, the upper signal coupler 32 may include a multiplier / analog multiplication circuit 326. The multiplier / analog multiplication circuit 326 may couple the received resonant current signal S2 and the preset carrier signal S3 to obtain a coupled current signal S4. The specific process may refer to the process of achieving coupling through the multiplier / analog multiplication circuit 326 described in the first embodiment, which will not be repeated here.

[0153] Optionally, in the above implementation, both the excitation signal S1 and the preset carrier signal S3 may be sinusoidal signals.

[0154] S102: A phase difference detector extracts a low-frequency signal component from a coupling current signal, and determines a phase difference signal according to the low-frequency signal component.

[0155] In some feasible implementations, the phase difference detector 33 may extract the low-frequency signal component of the coupled current signal S4 output by the signal coupler 32, and then determine the phase difference signal based on the low-frequency signal component. Here, the low-frequency signal component is a signal component in the coupled current signal S4 whose frequency is less than or equal to the first preset frequency. Here, the phase difference detector 33 extracts the low-frequency signal component of the coupled current signal S4 output by the signal coupler 32, and determines the phase difference signal based on the low-frequency signal component. The specific process can be referred to the process described in Example 1 in which the phase difference detector 33 extracts and determines the phase difference signal based on the low-frequency signal component, and will not be repeated here.

[0156] S103: The controller determines whether there is a foreign object in the detection area corresponding to the first resonant network according to the phase difference signal.

[0157] In some feasible implementations, after acquiring the phase difference signal S5 , the controller 30 can determine whether there is a foreign object in the detection area corresponding to the first resonant network 31 according to the phase difference signal S5 .

[0158] In a first optional implementation, after acquiring the phase difference signal S5, the controller 30 may first determine the amplitude of the phase difference signal S5. Here, in combination with the above example, the amplitude of the phase difference signal S5 is Then, the controller 30 may determine whether the amplitude of the phase difference signal S5 is less than the first preset amplitude and greater than the second preset amplitude. If the controller 30 determines that the detection area corresponding to the first resonant network 31 is free of foreign matter, the detection area corresponding to the first resonant network 31 is free of foreign matter. If the amplitude is greater than or equal to the first preset amplitude, or less than or equal to the second preset amplitude, it can be determined that there is a foreign object in the detection area corresponding to the first resonant network 31.

[0159] In a second optional implementation, the foreign object detection device may further include an amplitude detector 34, and the controller 30 may control the amplitude detector 34 to detect the target signal amplitude of the resonant current signal S2. The specific detection process may refer to the corresponding description in the first embodiment, which will not be repeated here. Then, the controller 30 may determine whether there is a foreign object in the detection area corresponding to the first resonant network 31 according to the peak value of the target signal and the amplitude of the phase difference signal S5.

[0160] Optionally, after determining the amplitude of the phase difference signal S5, the controller 30 may calculate the divisor (for the convenience of description, assumed to be R1 here) of the amplitude of the phase difference signal S5 and the amplitude of the target signal. Then, if the controller 30 determines that the divisor R1 is greater than the second preset threshold and less than the first preset threshold, it can be determined that there is no foreign matter in the detection area corresponding to the first resonant network 31. If the controller 30 determines that the divisor R1 is less than or equal to the second preset threshold, or greater than or equal to the first preset threshold, it can be determined that there is a foreign matter in the detection area corresponding to the first resonant network 31.

[0161] Optionally, after determining the target signal amplitude and the amplitude of the phase difference signal S5, the controller 30 may determine the divisor (also assumed to be R1 here) of the amplitude of the phase difference signal S5 and the amplitude of the target signal. Then, if the controller 30 determines that the target signal amplitude is greater than or equal to the third preset amplitude, and determines that the divisor R1 is greater than or equal to the first preset threshold, or is less than or equal to the second preset threshold, it is determined that there is a foreign object 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 determines that the divisor R1 is greater than the second preset threshold and less than the first preset threshold, it is determined that there is no foreign object in the detection area corresponding to the first resonant network 31.

[0162] It should be added that, in some optional implementations, the foreign body detection device may further include a signal generator 35, and the controller 30 may control the signal generator 35 through a signal control instruction to generate an excitation signal S1 of a corresponding frequency and a preset carrier signal S3. The excitation signal S1 and the preset carrier signal S3 may be indicated by the signal control instruction. The specific process of the controller 30 controlling the signal generator 35 through a signal control instruction to generate an excitation signal S1 of a corresponding frequency and a preset carrier signal S3 may refer to the process described in the first embodiment, and will not be repeated here.

[0163] In some optional implementations, the foreign object detection device may further include a current detector 38. When the first resonant network 31 works 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 amplify the current to convert it into the above-mentioned resonant current signal S2. Here, the specific process of the current detector 38 detecting the resonant current signal S2 can refer to the corresponding content described in the first embodiment, and will not be repeated here.

[0164] 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 through a resonant network selection signal to select the first resonant network 31 or the second resonant network 37 for foreign object detection, thereby realizing detection of unused detection areas. Here, the specific process of the controller 30 controlling the switching module 36 through a resonant network selection signal to select the first resonant network 31 or the second resonant network 37 for foreign object detection can be referred to the process described in the first embodiment, and will not be repeated here.

[0165] In this embodiment, the signal coupler 32 and the phase difference detector 33 can directly detect and obtain a phase difference signal S6 that can indicate the phase difference between the excitation signal S1 input by the first resonant network 31 and the resonant current signal S2 output by the first resonant network 31, and the controller 30 can simply process the phase difference signal S6 to determine whether there is a foreign object in the detection area corresponding to the first resonant network. This method can reduce the complexity and cost of the entire detection system on the one hand, and on the other hand, it can also avoid the problem of low detection accuracy caused by the current parameter or voltage parameter being easily disturbed by the main power in the method of directly performing foreign object detection based on the measured current parameter or voltage parameter.

[0166] See also Fig.17 , Fig.17 is a schematic diagram of the structure of another wireless charging system provided in an embodiment of the present application. Fig.17As shown, the present application also provides a wireless charging transmitting end device 170, which may include a power transmitting device 1701 and a foreign object detection device as described in the previous embodiment one or embodiment two (here marked as 1702). 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 above-mentioned foreign object detection device 1702 can be arranged 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 can be used to detect whether there is a foreign object between the power receiving device 1711 and the power transmitting device 1701. It should be noted that in actual implementation, the power transmitting device 1701 corresponds to the previous Figure 1 and Figure 2 The wireless charging transmitter 1010 shown in FIG. 17 is a power receiving device 1711 corresponding to the wireless charging transmitter 1010 shown in FIG. Figure 1 and Figure 2 The wireless charging receiving device 1000 is shown. The power transmitting device 1701 may include a power transmitting coil, the power receiving device 1711 may include a power receiving coil, and the foreign object detection device 1702 may be arranged on a side of the power transmitting coil facing the power receiving coil.

[0167] See also Fig.18 , Fig.18 is a schematic diagram of the structure of another wireless charging system provided in an embodiment of the present application. Fig.18 As shown, the present application also provides a wireless charging receiving end device 180, and the wireless charging transmitting end device 180 may include a power receiving device 1801 and a foreign object detection device (here marked as 1802) as described in the previous embodiment one or embodiment two. 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 can be specifically arranged 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 can be used to detect whether there is a foreign object between the power receiving device 1801 and the power transmitting device 1811. It should be noted that in actual implementation, the power transmitting device 1811 corresponds to the power transmitting device 1811 described above. Figure 1 and Figure 2 The wireless charging transmitter 1010 shown in FIG. 1010 is a wireless charging transmitter 1010 shown in FIG. 1010. The power receiving device 1801 corresponds to the wireless charging transmitter 1010 shown in FIG. Figure 1 and Figure 2The wireless charging receiving device 1000 is shown. The power transmitting device 1811 may include a power transmitting coil, the power receiving device 1801 may include a power receiving coil, and the foreign object detection device 1802 may be arranged on a side of the power transmitting coil facing the power receiving coil.

[0168] It should be understood that in the description of the present application, unless otherwise specified, " / " means "or", for example, A / B can mean A or B. "And / or" in this article is merely a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, "at least one" means one or more, and "plurality" means two or more. The words "first", "second", etc. do not limit the quantity and execution order, and the words "first", "second", etc. do not limit them to be different.

[0169] In the description of this application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in this application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0170] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in terms of function in the above description. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0171] In the embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the devices described above are only schematic, for example, the division of units is only a logical function division, and there may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, or it can be an electrical, mechanical or other form of connection.

[0172] In addition, each functional unit in the embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0173] In short, the above is only a preferred embodiment of the technical solution of this application, and is not intended to limit the protection scope of this application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this application should be included in the protection scope of this application.

Claims

1. A foreign body detection device, characterized in that: The foreign object detection device comprises: a controller, a first resonant network, a signal coupler and a phase difference detector; The signal coupler is used to obtain a resonant current signal when the first resonant network works normally under the action of an excitation signal, couple a preset carrier signal and the resonant current signal to obtain a coupled current signal, and transmit the coupled current signal to the phase difference detector, wherein the preset carrier signal has the same frequency as the excitation signal; The phase difference detector is used to extract the low-frequency signal component in the coupled current signal, determine the phase difference signal according to the low-frequency signal component and transmit the phase difference signal to the controller, wherein the low-frequency signal component is a signal component in the coupled current signal whose frequency is less than or equal to the first preset frequency, and the amplitude of the phase difference signal corresponds to the phase difference between the excitation signal and the resonant current signal; The controller is used to determine whether there is a foreign object in the detection area corresponding to the first resonant network according to the amplitude of the phase difference signal.

2. The foreign matter detection device according to claim 1, characterized in that: The foreign matter detection device further includes: a current detector; When the first resonant network works normally under the action of the excitation signal, the current detector is used to detect the current output by the first resonant network to obtain the resonant current signal, and send the resonant current signal to the signal coupler.

3. The foreign matter detection device according to claim 1 or 2, characterized in that: The signal coupler comprises: a first inverter and a signal selector; The first inverter is used to phase-shift the resonant current signal to obtain a reverse resonant current signal, wherein the reverse resonant current signal has a phase difference of 180 degrees with the resonant current signal; The signal selector is used to select the resonant current signal or the reverse resonant current signal as a coupled current signal output according to the preset carrier signal.

4. The foreign matter detection device according to claim 3, characterized in that: The signal selector comprises: a first switch tube, a second switch tube and a second inverter; The first end of the first switch tube is connected to the preset carrier signal through the second inverter, the first end of the second switch tube is also connected to the preset carrier signal, the second end of the first switch tube is connected to the resonant current signal, the second end of the second switch tube is connected to the reverse resonant current signal, and the third end of the first switch tube is connected to the third end of the second switch tube and serves as the output end of the signal selector; The preset carrier signal is used to control the first switch tube to be turned on through the second inverter, and to control the second switch tube to be turned off so that the resonant current signal is output as the coupling current signal; Alternatively, the preset carrier signal is used to control the second switch tube to be turned on, and the first switch tube is controlled to be turned off through the second inverter so that the reverse resonant current signal is output as the coupled current signal.

5. The foreign matter detection device according to claim 4, characterized in that: The excitation signal is a sinusoidal 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.

6. The foreign matter detection device according to claim 1 or 2, characterized in that: The signal coupler includes a multiplier or an analog multiplication circuit; The multiplier or analog multiplication circuit is used to multiply the preset carrier signal and the resonant current signal to obtain the coupling current signal.

7. The foreign matter detection device according to claim 6, characterized in that: The excitation signal and the preset carrier signal are sinusoidal signals.

8. The foreign matter detection device according to claim 1 or 2, characterized in that: The controller is specifically used for: determining the amplitude of the phase difference signal; If it is determined 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, it is determined that there is a foreign object in the detection area corresponding to the first resonant network, wherein the first preset amplitude is greater than the second preset amplitude; If 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, it is determined that there is no foreign object in the detection area corresponding to the first resonant network.

9. The foreign matter detection device according to claim 1 or 2, characterized in that: The foreign matter detection device also includes an amplitude detector; The amplitude detector is used to detect the target signal amplitude of the resonant current signal; The controller is used to determine whether there is a foreign object in the detection area corresponding to the first resonant network according to the amplitude of the target signal and the amplitude of the phase difference signal.

10. The foreign matter detection device according to claim 9, characterized in that: The controller is specifically used for: determining the amplitude of the phase difference signal; If it is determined that the divisor of the amplitude of the phase difference signal and the amplitude of the target signal is greater than or equal to a first preset threshold, or less than or equal to a second preset threshold, it is determined that there is a foreign object in the detection area corresponding to the first resonant network; If it is determined that the divisor of the amplitude of the phase difference signal and the amplitude of the target signal is greater than the second preset threshold and less than the first preset threshold, it is determined that there is no foreign object in the detection area corresponding to the first resonant network.

11. The foreign matter detection device according to claim 9, characterized in that: The controller is specifically used for: determining the amplitude of the phase difference signal; If it is determined that the target signal amplitude is greater than or equal to a third preset amplitude, and the divisor of the amplitude of the phase difference signal and the target signal amplitude is greater than or equal to a first preset threshold, or is less than or equal to a second preset threshold, it is determined that there is a foreign object 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 divisor 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, it is determined that there is no foreign object in the detection area corresponding to the first resonant network.

12. The foreign matter detection device according to claim 1 or 2, characterized in that: The foreign matter detection device further comprises a signal generator, and the signal generator is used for: The preset carrier signal and the excitation signal are generated according to the signal control instruction sent by the controller, wherein the frequencies of the preset carrier signal and the excitation signal are indicated by the signal control instruction.

13. The foreign matter detection device according to claim 12, characterized in that: The foreign object detection device further includes a second resonant network and a switching module, wherein the second resonant network and the first resonant network are respectively connected to the switching module; The switching module is used for: The excitation signal generated by the signal generator is transmitted to the first resonant network or the second resonant network according to a resonant network selection signal from the controller.

14. A foreign body detection method, characterized in that: 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 comprises: The signal coupler couples the resonant current signal when the first resonant network works normally under the action of the excitation signal with a preset carrier signal to obtain a coupled current signal; The phase difference detector extracts a low-frequency signal component from the coupling current signal, and determines a phase difference signal according to the low-frequency signal component, wherein the low-frequency signal component is a signal component in the coupling current signal whose frequency is less than or equal to a first preset frequency, and the amplitude of the phase difference signal is used to indicate a phase difference between the excitation signal and the resonant current signal; The controller determines whether there is a foreign object in the detection area corresponding to the first resonant network according to the phase difference signal.

15. The method according to claim 14, characterized in that The foreign matter detection device further includes: a current detector; The method further comprises: When the first resonant network works normally under the action of the excitation signal, the current detector detects the current output by the first resonant network to obtain the resonant current signal.

16. The method according to claim 14 or 15, characterized in that The signal coupler comprises: a first inverter and a signal selector; The signal coupler couples the resonant current signal of the first resonant network when it works normally under the action of the excitation signal with a preset carrier signal to obtain a coupled current signal, including: The first inverter performs a phase shift on the resonant current signal to obtain a reverse resonant current signal, wherein a phase difference between the reverse resonant current signal and the resonant current signal is 180 degrees; The signal selector selects the resonant current signal or the reverse resonant current signal according to the preset carrier signal to output as a coupling current signal.

17. The method according to claim 16, characterized in that The signal selector comprises: a first switch tube, a second switch tube and a second inverter, the first end of the first switch tube is connected to the preset carrier signal through the second inverter, the first end of the second switch tube is also connected to the preset carrier signal, the second end of the first switch tube is connected to the resonant current signal, the second end of the second switch tube is connected to the reverse resonant current signal, and the third end of the first switch tube is connected to the third end of the second switch tube and serves as the output end of the signal selector; The signal selector selects the resonant current signal or the reverse resonant current signal according to the preset carrier signal to output as a coupling current signal, comprising: The preset carrier signal flowing through the second inverter connected to the first end of the first switch tube controls the first switch tube to be turned on, and the preset carrier signal connected to the first end of the second switch tube controls the second switch tube to be turned off, so that the resonant current signal is output as the coupling current signal; Alternatively, a preset carrier signal connected to the first end of the second switch tube controls the second switch tube to be turned on, and a preset carrier signal connected to the first end of the first switch tube and flowing through the second inverter controls the first switch tube to be turned off, so that the reverse resonant current signal is output as the coupled current signal.

18. The method according to claim 14 or 15, characterized in that The signal coupler includes a multiplier or an analog multiplication circuit; The signal coupler couples the resonant current signal of the first resonant network when it works normally under the action of the excitation signal with a preset carrier signal to obtain a coupled current signal, including: The preset carrier signal and the resonant current signal are multiplied by the multiplier or the analog multiplication circuit to obtain the coupling current signal.

19. The method according to claim 14 or 15, characterized in that The foreign matter detection device also includes an amplitude detector; The method further comprises: The amplitude detector detects a target signal amplitude of the resonant current signal.

20. The method according to claim 19, characterized in that The controller determines whether there is a foreign object in the detection area corresponding to the first resonant network according to the phase difference signal, including: The controller determines the amplitude of the phase difference signal; If the controller determines that the divisor of the amplitude of the phase difference signal and the amplitude of the target signal is greater than or equal to a first preset threshold, or less than or equal to a second preset threshold, it is determined that there is a foreign object in the detection area corresponding to the first resonant network; If the controller determines that the divisor of the amplitude of the phase difference signal and the amplitude of the target signal is greater than the second preset threshold and less than the first preset threshold, it is determined that there is no foreign object in the detection area corresponding to the first resonant network.

21. The method according to claim 19, characterized in that The controller determines whether there is a foreign object in the detection area corresponding to the first resonant network according to the phase difference signal, including: The controller determines the amplitude of the phase difference signal; If the controller determines that the target signal amplitude is greater than or equal to a third preset amplitude, and the divisor of the amplitude of the phase difference signal and the target signal amplitude is greater than or equal to a first preset threshold, or is less than or equal to a second preset threshold, it is determined that there is a foreign object 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 determines that the divisor 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, it is determined that there is no foreign object in the detection area corresponding to the first resonant network.

22. A wireless charging transmitter device, characterized in that: The wireless charging transmitting end device comprises a power transmitting device and a foreign object detection device as claimed in any one of claims 1 to 13; Wherein, the foreign object detection device is arranged on a side of the power transmitting device facing the power receiving device of wireless charging, and the power receiving device is included in the wireless charging receiving end device corresponding to the wireless charging transmitting end device.

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