Wireless charging foreign matter detection method, device, and equipment, and storage medium

Abstract

This application discloses a method, apparatus, device, and storage medium for detecting foreign objects in wireless charging, relating to the field of wireless charging technology. The method includes: before power transmission is initiated in the wireless charging system, controlling the transmitting end to apply a low-power AC excitation signal to the transmitting coil; within a continuous time window, repeatedly measuring the port impedance parameters of the transmitting coil at a fixed sampling rate to obtain a time series of impedance parameters; performing a Fourier transform on the time series to obtain a power spectral density distribution; and detecting the type of foreign object based on feature information associated with the type of foreign object in the power spectral density distribution. Since the power spectral density distribution itself contains feature information that can be used to distinguish the type of foreign object, no external sensors are required; detection of the type of foreign object can be achieved simply by analyzing the feature information in the power spectral density distribution. This method is unaffected by the environment and is particularly effective for detecting stationary foreign objects.

Description

Technical Field

[0001] This application relates to the field of wireless charging technology, and in particular to a method, apparatus, device and storage medium for detecting foreign objects in wireless charging. Background Technology

[0002] In the field of wireless charging technology, especially in high-power wireless charging systems for electric vehicles, a significant gap exists between the transmitting coil (ground side) and the receiving coil (vehicle side). During charging, a high-frequency alternating magnetic field covers this gap area. When metallic foreign objects such as coins, iron pieces, or tools enter this area, the eddy current effect causes the foreign object to heat up rapidly, potentially igniting surrounding flammable materials. If living organisms, such as cats or dogs, are accidentally exposed to a high-intensity magnetic field for extended periods, it may cause tissue damage. Therefore, foreign object detection in the charging area before and during charging is an essential safety feature of wireless charging systems.

[0003] Among related technologies, the first category is detection methods based on electromagnetic parameters, such as power loss detection. These methods determine the presence of foreign objects by comparing the power difference between the transmitter and receiver. However, these methods can only determine the presence of foreign objects between the transmitter and receiver, and cannot identify whether the foreign object is a living organism. The second category is liveness detection methods based on external sensors, including cameras, millimeter-wave radar, infrared thermal imaging, and capacitive sensing arrays. These methods require additional hardware to identify live organisms, and their reliability decreases significantly in nighttime scenarios. Furthermore, the accuracy of live organism detection often depends on the movement of the living organism.

[0004] Therefore, how to accurately detect and classify foreign objects in the charging area without adding any external sensors is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] This application provides a method, apparatus, device, and storage medium for detecting foreign objects in wireless charging, which can accurately detect and classify foreign objects in the charging area without adding any external sensors.

[0006] On one hand, embodiments of this application provide a method for detecting foreign objects during wireless charging, including: Before the wireless charging system starts power transmission, the control transmitter applies a low-power AC excitation signal to the transmitting coil; Within a continuous time window, the port impedance parameters of the transmitting coil are measured multiple times at a fixed sampling rate to obtain a time series of the impedance parameters; Perform a Fourier transform on the time series to obtain the power spectral density distribution; Foreign object types are detected based on the feature information associated with foreign object types in the power spectral density distribution.

[0007] On one hand, embodiments of this application provide a wireless charging foreign object detection device, including: The transmitting module is used to control the transmitting end to apply a low-power AC excitation signal to the transmitting coil before the wireless charging system starts power transmission; The measurement module is used to measure the port impedance parameters of the transmitting coil multiple times at a fixed sampling rate within a continuous time window to obtain the time series of the impedance parameters; The transformation module is used to perform Fourier transform on the time series to obtain the power spectral density distribution; The detection module detects the type of foreign object based on the feature information associated with the type of foreign object in the power spectral density distribution.

[0008] In one possible embodiment, the transmitting module is further configured to: control the transmitting end to send a detection command to the receiving end via wireless communication; wherein, after receiving the detection command, the receiving end will electrically isolate the receiving coil from the battery load and send an acknowledgment reply to the transmitting end, the acknowledgment reply being used to indicate that the receiving end is in an open circuit state; after receiving the acknowledgment reply, apply a low-power AC excitation signal to the transmitting coil.

[0009] In one possible embodiment, the measurement module is used to: set the duration of a continuous time window so that it covers at least multiple physiological activity cycles; wherein the physiological activity cycle characterizes the periodic physiological rhythms generated by a living organism due to heartbeat and / or respiration; within the continuous time window, sequentially collect port impedance parameters at each sampling time according to a fixed sampling rate; and arrange the port impedance parameters in chronological order to form a time series of impedance parameters.

[0010] In one possible embodiment, the transformation module is used to: determine the number of transformation points of the Fourier transform based on the number of sampling points of the time series, so that the Fourier transform can distinguish the frequency components of the physiological activities of living organisms; perform Fourier transform on the time series according to the number of transformation points to obtain the complex spectrum of the time series at discrete frequency points; calculate the squared value or amplitude of each complex spectrum, and use the squared value or amplitude as the power spectral density value at the corresponding frequency point to obtain the power spectral density distribution.

[0011] In one possible embodiment, the detection module is used to: detect whether the power spectral density distribution meets the following conditions: there is a spectral component corresponding to the frequency range of physiological activities of a living organism, and the amplitude of the spectral component exceeds a preset amplitude; if so, it is determined that there is a living organism foreign body; if not, it is determined whether there is a non-living foreign body and the type of non-living foreign body based on the trend of impedance parameter change with frequency.

[0012] In one possible embodiment, the detection module is configured to: apply at least two low-power excitation signals of different frequencies to the transmitting coil, measure the equivalent series resistance and equivalent series inductance at each frequency; calculate the fitting exponent of the equivalent series resistance as a function of frequency, and the relative rate of change of the equivalent series inductance between the lowest and highest frequencies; determine the presence of a metallic foreign object when the fitting exponent is greater than a first threshold and the relative rate of change is greater than a second threshold; determine the presence of a water-containing non-living foreign object when the fitting exponent is between a third and a fourth threshold and the relative rate of change is less than a fifth preset threshold; wherein the first threshold is greater than the third threshold, the third threshold is greater than the fourth threshold, and the fifth threshold is less than the second threshold; otherwise, determine that no non-living foreign object exists.

[0013] In one possible embodiment, the device further includes: an alarm module, used to apply a detection signal to the transmitting coil during the power transmission gap of the wireless charging system to measure the equivalent series resistance of the transmitting coil; compare the currently measured equivalent series resistance with a reference value recorded before charging starts; when the change in the equivalent series resistance exceeds a sixth threshold, determine that a foreign object has entered the charging area during the charging process, then interrupt the power transmission and issue an alarm signal.

[0014] On one hand, embodiments of this application provide an electronic device, which includes a processor and a memory, wherein the memory stores program code, and when the program code is executed by the processor, the processor executes any of the above-mentioned wireless charging foreign object detection methods.

[0015] On the one hand, this application provides a computer-readable storage medium including program code, which, when the storage medium is run on an electronic device, causes the electronic device to execute any of the above-mentioned wireless charging foreign object detection methods.

[0016] The technical effects achieved by the wireless charging foreign object detection method, apparatus, device, and storage medium provided in this application are as follows: First, different types of foreign objects exhibit different frequency domain characteristics in their power spectral density distribution, which is the core basis for this scheme to identify foreign object types. Living organisms, due to physiological activities such as heartbeat and respiration, produce periodic impedance fluctuations, which, after Fourier transform, form significant power spectral peaks in the frequency band corresponding to the physiological activity frequency. Metallic foreign objects and water-containing non-living foreign objects do not produce such periodic fluctuations; their power spectral density distribution does not have significant peaks in the frequency band corresponding to the physiological activity frequency, but exhibit different patterns in impedance change trends under multi-frequency sweeps. Based on these differences in frequency domain characteristics, this scheme analyzes whether there is feature information in the power spectral density distribution associated with the foreign object type to detect the foreign object type, thus distinguishing between living organisms and non-living foreign objects. Furthermore, the impedance parameter variation trend with frequency can be used to further distinguish between metallic foreign objects and water-containing non-living foreign objects.

[0017] Secondly, this solution fully reuses existing wireless charging hardware, requiring no additional external sensors. Foreign object detection can be achieved solely through software algorithm upgrades, significantly reducing system costs. Furthermore, the detection is based on time-frequency analysis of electromagnetic field parameters, independent of optical, infrared, or radio frequency echo signals. Therefore, it is unaffected by environmental factors such as light, rain, fog, and temperature, enabling stable operation in all weather conditions.

[0018] Finally, this scheme can extract weak periodic signals caused by the physiological activities of living organisms from background noise through multiple sampling and Fourier transform within a continuous time window. Even if the living organism is completely still, it can be reliably detected, filling the technical deficiency of existing motion detection schemes that have a detection blind spot for stationary living organisms. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0020] Figure 1 This is a flowchart illustrating the implementation of a wireless charging foreign object detection method in this application.

[0021] Figure 2 This is a flowchart illustrating the steps of a foreign object classification and detection method in an embodiment of this application.

[0022] Figure 3 This is a schematic diagram of the structure of a wireless charging foreign object detection device according to an embodiment of this application.

[0023] Figure 4 This is a schematic diagram of the hardware structure of an electronic device according to an embodiment of this application. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. Unless otherwise specified, the embodiments and features in the embodiments of this application can be arbitrarily combined with each other. Furthermore, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than that shown here.

[0025] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that embodiments of the invention described herein can be implemented in sequences other than those illustrated or described herein.

[0026] The design concept of the embodiments of this application is briefly introduced below: In the field of wireless charging technology, especially in high-power wireless charging systems for electric vehicles, a significant gap exists between the transmitting and receiving coils. During charging, a high-frequency alternating magnetic field covers this gap area. When metallic foreign objects such as coins, metal pieces, or tools enter this area, the eddy current effect causes the foreign object to heat up rapidly, potentially igniting surrounding flammable materials. If living organisms, such as cats or dogs, are accidentally exposed to a high-intensity magnetic field for extended periods, it may cause tissue damage. Therefore, foreign object detection in the charging area before and during charging is an essential safety feature of wireless charging systems.

[0027] In view of this, embodiments of this application provide a method, apparatus, device, and storage medium for detecting foreign objects in wireless charging. The method includes: before power transmission is initiated in the wireless charging system, controlling the transmitting end to apply a low-power AC excitation signal to the transmitting coil; within a continuous time window, repeatedly measuring the port impedance parameters of the transmitting coil at a fixed sampling rate to obtain a time series of the impedance parameters; performing a Fourier transform on the time series to obtain a power spectral density distribution; and detecting the type of foreign object based on the feature information associated with the type of foreign object in the power spectral density distribution. Thus, the power spectral density distribution is obtained by performing a Fourier transform on the time series of the transmitting coil port impedance parameters. Since different types of foreign objects affect the power spectral density distribution in different ways, the distribution itself contains feature information that can be used to distinguish the type of foreign object. Based on this, this solution does not require any external sensors; it can detect the type of foreign object simply by analyzing the feature information in the power spectral density distribution, is unaffected by the environment, and has a significant effect on detecting stationary foreign objects.

[0028] The preferred embodiments of this application are described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit this application. Furthermore, the embodiments and features in the embodiments of this application can be combined with each other without conflict.

[0029] refer to Figure 1 The following is a flowchart illustrating the implementation of a wireless charging foreign object detection method according to an embodiment of this application. The specific implementation process of this method is as follows: S101 controls the transmitter to apply a low-power AC excitation signal to the transmitting coil before the wireless charging system starts power transmission.

[0030] In this embodiment, the power converter of the wireless charging system mainly consists of two parts: a power factor correction (PFC) circuit and a DC-DC converter (DC / DC) circuit. It is divided into a transmitter and a receiver, with the DC / DC isolation transformer as the boundary. The transmitter's PFC section comprises an input electromagnetic interference (EMI) circuit, a pre-charge circuit, and a three-phase full-bridge circuit to convert three-phase AC power into DC power. After passing through the DC / DC chopper circuit, the DC power is transmitted through the transmitting coil. The receiver consists of a DC / DC rectifier circuit, an output EMI filter circuit, a series-parallel switching circuit, and a reverse polarity protection circuit to convert the received energy and meet charging requirements. The transmitter controller implements PFC power conversion control, DC / DC chopper control, alignment circuit control, and human-machine interaction; the receiver controller implements output series-parallel switching control to achieve a wide range of output.

[0031] Before the wireless charging system initiates power transmission, to ensure the receiver is in a known and stable electrical state during detection, and to eliminate interference from receiver load changes on transmitter impedance measurement, thereby improving the accuracy and reliability of foreign object detection, the transmitter controller sends a detection command to the receiver via wireless communication. Upon receiving the detection command, the receiver controller controls electrical isolation between the receiving coil and the battery load and sends an acknowledgment reply to the transmitter, indicating that the receiver is in an open-circuit state. After receiving the acknowledgment reply, the transmitter controller controls the transmitter inverter (three-phase full-bridge circuit) to apply a low-power AC excitation signal to the transmitting coil. The power and frequency of the low-power AC excitation signal are set by the transmitter controller according to a preset program and used for subsequent impedance sampling. The entire control process fully reuses existing hardware without the need for any external sensors.

[0032] Optionally, the power of the low-power AC excitation signal is less than 1 watt and the peak voltage is less than 10 volts to ensure safety for humans and animals during the detection process. The low-power AC excitation signal can be in single-frequency mode, with the frequency set to the operating frequency of the wireless charging system or the system's preset detection frequency, such as the operating frequency of the wireless charging system (85kHz) or the preset detection frequency (1MHz), for continuous impedance sampling required for live organism detection. Alternatively, it can be in multi-frequency sweep mode, where the number of frequency points and the frequency range of the multi-frequency sweep are preset by the transmitter controller according to the detection accuracy requirements to ensure that the fitting index of the equivalent series resistance changing with frequency has sufficient discriminative power. In multi-frequency sweep mode, multiple incremental frequency points are output sequentially, covering the low-frequency to high-frequency range, such as 100kHz, 300kHz, 500kHz, 800kHz, 1MHz, 1.5MHz, and 2MHz sequentially, with the highest sweep frequency not exceeding half of the self-resonant frequency of the transmitting coil to avoid interference from the coil's own resonance on the detection results, for impedance spectrum analysis required for non-living foreign object classification.

[0033] Optionally, the transmitter inverter can use gallium nitride power devices, whose high-frequency switching characteristics are beneficial for achieving wide-range frequency sweep excitation.

[0034] The above technical solution, by controlling the open circuit at the receiving end, eliminates interference from the receiving end load on impedance measurement, creating a stable electrical environment for subsequent detection. Simultaneously, it reuses existing hardware to apply low-power single-frequency or multi-frequency excitation signals without adding any sensors, and the power is strictly limited within a safe range. This provides a foundation for subsequent high-precision foreign object identification, ensuring the reliability and safety of the detection.

[0035] S102, within a continuous time window, the port impedance parameters of the transmitting coil are measured multiple times at a fixed sampling rate to obtain a time series of impedance parameters.

[0036] In this embodiment of the application, after the control transmitter applies a low-power AC excitation signal to the transmitting coil, the port impedance parameters of the transmitting coil are measured multiple times at a fixed sampling rate within a continuous time window to obtain a time series of the impedance parameters. Specifically, this includes: First, the duration of the continuous time window is set to cover at least multiple physiological activity cycles. These physiological activity cycles represent the periodic physiological rhythms of a living organism caused by heartbeat and / or respiration. Specifically, the duration of the continuous time window can be 3 to 10 seconds. For example, in humans, the respiratory cycle at rest is approximately 3 to 5 seconds, and the heartbeat cycle is approximately 0.6 to 1 second; in common small animals such as cats and dogs, the respiratory cycle is approximately 0.3 to 2 seconds, and the heartbeat cycle is approximately 0.4 to 0.6 seconds. Setting the duration of the continuous time window to cover at least multiple physiological activity cycles—for example, 5 seconds can cover one respiratory cycle and multiple heartbeat cycles in humans, and 10 seconds can cover multiple respiratory and heartbeat cycles in small animals—ensures that the frequency components corresponding to heartbeat and / or respiration can be effectively identified in the power spectral density distribution after Fourier transform.

[0037] Then, within a continuous time window, port impedance parameters are sequentially acquired at each sampling moment according to a fixed sampling rate. This fixed sampling rate can range from 10Hz to 50Hz. Taking the human heartbeat frequency of approximately 1.67Hz as an example, according to the Nyquist sampling theorem, a sampling rate of at least 3.34Hz is required to reconstruct the heartbeat signal without distortion; 10Hz already meets this requirement. For small animals with a heartbeat frequency of approximately 10Hz, the sampling rate needs to be at least greater than 20Hz. Therefore, a sampling rate of 50Hz can sufficiently guarantee the acquisition quality of high-frequency physiological signals. Simultaneously, the sampling rate of 10Hz to 50Hz generates 30 to 500 sampling points within a time window of 3 to 10 seconds. This data volume places a low computational burden on the Fourier transform and can be processed in real-time on a low-cost embedded controller.

[0038] Finally, the port impedance parameters are arranged in chronological order to form a time series of impedance parameters. Here, the port impedance parameters refer to the equivalent electrical parameters of the transmitting coil ports, used to characterize the electromagnetic response characteristics of the transmitting coil under AC excitation. Specifically, the port impedance parameters include at least one of the following: Equivalent series resistance: reflects the loss characteristics of electromagnetic energy by the transmitting coil and its surrounding medium. When a metallic foreign object enters the charging area, the eddy current effect will cause the equivalent series resistance to increase significantly. When a living organism enters, its dielectric loss will also cause the equivalent series resistance to change periodically. Quality factor: It comprehensively reflects the energy storage and loss characteristics of the transmitting coil. The presence of foreign objects will cause the quality factor to decrease. Impedance magnitude: Changes in impedance magnitude can also reflect the influence of foreign objects on the electromagnetic field.

[0039] The impedance parameters mentioned above are correlated, and one or more combinations can be selected as the basis for detection based on the actual detection accuracy and computational complexity requirements.

[0040] A time series is a data sequence formed by sequentially collecting port impedance parameters within a continuous time window at a fixed sampling rate and arranging them in chronological order of collection time. For example, using the equivalent series resistance Rs as the acquisition parameter, with a sampling rate of 20Hz and a time window of 5 seconds, Rs values ​​are collected every 0.05 seconds, for a total of 100 data points. Arranging these data points in chronological order yields Rs(t1), Rs(t2), ..., Rs(t100), which is the time series of Rs. This time series completely records the trajectory of the impedance parameter's continuous change over time. If a living organism is present in the charging area, the periodic impedance fluctuations caused by its heartbeat and respiration will be recorded in this sequence, providing a data basis for subsequent Fourier transform and power spectral density analysis. Similarly, if the quality factor or impedance magnitude is collected, a corresponding time series can be formed in the same way.

[0041] The aforementioned technical solution, by setting a time window covering multiple physiological activity cycles and a sampling rate satisfying the Nyquist theorem, continuously acquires the port impedance parameters of the transmitting coil and forms a time series. This time series completely records the continuous change trajectory of the impedance parameters over time, transforming the weak periodic impedance fluctuations caused by the heartbeat and respiration of living organisms into a processable data format. Compared to traditional single static measurements, this solution provides a rich data foundation containing time-dimensional information for subsequent frequency domain analysis, enabling the effective extraction of physiological characteristic signals hidden in the time domain.

[0042] S103, perform Fourier transform on the time series to obtain the power spectral density distribution.

[0043] In this embodiment of the application, after acquiring the aforementioned time series, a Fourier transform is performed on the time series to obtain the power spectral density distribution. Specific implementation methods include: First, based on the number of sampling points in the time series, the number of transform points for the Fourier transform is determined to ensure that the Fourier transform can distinguish the frequency components of physiological activities in living organisms. The number of transform points determines the frequency resolution; more transform points result in higher frequency resolution and a greater ability to distinguish similar frequency components. To ensure that the Fourier transform can effectively distinguish the frequency components of physiological activities in living organisms from the power spectral density distribution—for example, distinguishing the subtle difference between a human heartbeat (approximately 1.67 Hz) and a small animal's heartbeat (approximately 2.3 Hz)—the number of transform points needs to be reasonably determined based on the number of sampling points in the time series. For instance, when the sampling rate is 20 Hz and the number of sampling points is 100, if the number of transform points is 128 (padded with zeros to powers of 2), then the frequency resolution = sampling rate / number of transform points = 20 / 128 ≈ 0.156 Hz. This resolution is sufficient to distinguish physiological frequency differences greater than 0.2 Hz.

[0044] To ensure sufficient frequency resolution while also considering the controller's computational efficiency, the number of transformation points is usually chosen to be an integer power of 2, such as 64, 128, 256, or 512 points, in order to facilitate the efficient execution of the Fourier transform algorithm.

[0045] Then, a Fourier transform is performed on the time series according to the number of transform points to obtain the complex spectrum of the time series at discrete frequency points. The purpose of the Fourier transform is to convert the time series from the time domain to the frequency domain. Assuming the time series has 100 sampling points and the number of transform points is 128 (padded with zeros if necessary), the transformed data will have a complex spectrum at 128 discrete frequency points. Each complex spectrum contains a real part and an imaginary part. The real part reflects the in-phase component of that frequency component, and the imaginary part reflects the quadrature component. According to the Nyquist sampling theorem, the highest signal frequency that can be recovered without distortion is half of the sampling rate. Frequency components above half of the sampling rate will experience spectral aliasing and cannot accurately reflect the original signal. Therefore, taking a sampling rate of 20Hz and a transform point of 128 points as an example, the resolvable frequency range is 0Hz to 10Hz, and the interval between adjacent frequency points is approximately 0.156Hz. In this way, the 1.67Hz signal generated by the heartbeat of a living organism will fall on the corresponding frequency point, and the 0.3Hz signal generated by respiration will also fall on the corresponding frequency point, making it easier to identify these physiological frequency components from the power spectral density distribution.

[0046] Finally, the squared amplitude or magnitude of each complex spectrum is calculated, and this squared amplitude or magnitude is used as the power spectral density value at the corresponding frequency point to obtain the power spectral density distribution. The complex spectrum reflects the amplitude and phase information of the frequency components. To obtain the power spectral density distribution, the squared amplitude or magnitude of the complex spectrum at each discrete frequency point needs to be calculated. Taking the squared amplitude as an example, if the complex spectrum at a certain frequency point is A+jB, then the squared amplitude is A²+B², which reflects the energy magnitude of that frequency component. Taking the magnitude as an example, √(A²+B²) is calculated, reflecting the amplitude magnitude of that frequency component. Arranging the squared amplitude or magnitude of all discrete frequency points in frequency order yields the power spectral density distribution. The horizontal axis of the power spectral density distribution represents frequency, and the vertical axis represents energy or amplitude, used to characterize the energy distribution of different frequency components.

[0047] Because the heartbeat and respiration of a living organism produce high energy peaks at corresponding frequency points (such as 1.67Hz), while foreign objects or non-living foreign objects do not show obvious peaks in this frequency band, the presence of a living organism in the charging area can be determined by observing whether there are energy peaks in the power spectral density distribution corresponding to the frequency of physiological activity.

[0048] S104, based on the feature information associated with the type of foreign object in the power spectral density distribution, detect the type of foreign object.

[0049] In this embodiment, after calculating the power spectral density distribution corresponding to the time series, the presence and type of foreign objects are detected based on the feature information associated with the foreign object type in the power spectral density distribution. The specific implementation method can be found in [reference needed]. Figure 2 .

[0050] like Figure 2 The diagram shown is a flowchart of a foreign object classification and detection method provided in an embodiment of this application, which specifically includes the following steps: S201, detect whether the power spectral density distribution has spectral components corresponding to the frequency range of physiological activities of living organisms, and whether the amplitude of the spectral components exceeds the preset amplitude. S202, if so, then it is determined that there is a living biological foreign object; S203, if not, apply at least two low-power excitation signals of different frequencies to the transmitting coil and measure the equivalent series resistance and equivalent series inductance at each frequency; S204, calculate the fitting exponent of the equivalent series resistance as a function of frequency, and the relative rate of change of the equivalent series inductance between the lowest and highest frequencies. S205, determine whether the fitting index is greater than the first threshold and the relative rate of change is greater than the second threshold; S206, if so, it is determined that a metallic foreign object is present; S207, if not, determine whether the fitting index is between the third threshold and the fourth threshold and the relative rate of change is less than the fifth preset threshold; S208, if so, determine that there is a non-living water-containing foreign object; wherein, the first threshold is greater than the third threshold, the third threshold is greater than the fourth threshold, and the fifth threshold is less than the second threshold; S209. If not, determine that there is no non-living foreign body.

[0051] In this embodiment, after the transmitter controller determines that no living organism is present through liveness detection, it will further determine whether there are metallic foreign objects or non-living foreign objects containing water, such as wet towels or fruit. Specifically: First, the transmitter controller controls the transmitter inverter to sequentially apply at least two low-power excitation signals of different frequencies to the transmitter coil, such as 100kHz, 300kHz, 500kHz, 800kHz, 1MHz, 1.5MHz, and 2MHz. At each frequency, the equivalent series resistance Rs and equivalent series inductance Ls of the transmitter coil are measured.

[0052] Then, based on the measured data, two key parameters are calculated: (1) Fitting index k of equivalent series resistance with frequency. Since metallic foreign objects cause the resistance to rise rapidly with frequency, the value of k is relatively large, such as greater than 0.8 or 0.85; while water-containing non-living foreign objects cause the resistance to rise slowly with frequency, so the value of k is moderate, such as 0.2 to 0.7.

[0053] (2) The relative rate of change of the equivalent series inductance between the lowest and highest frequencies, ΔL / L, where ΔL represents the change in the equivalent series inductance, i.e., the inductance difference of the transmitting coil between the lowest and highest frequencies, and L represents the equivalent series inductance. Due to the eddy current demagnetization effect of metallic foreign objects, the inductance will decrease significantly, so ΔL / L is relatively large, for example, greater than 10% or 12%; while water-containing non-living foreign objects have little effect on the inductance, so ΔL / L is relatively small, for example, less than 5% or 4%.

[0054] Finally, a comprehensive judgment is made based on the values ​​of k and ΔL / L: when k is greater than the first threshold (e.g., greater than 0.8) and ΔL / L is greater than the second threshold (e.g., greater than 10%), it is determined that there is a metallic foreign object in the charging area; when k is between the fourth threshold (e.g., 0.2) and the third threshold (e.g., 0.7) and ΔL / L is less than the fifth threshold (e.g., 5%), it is determined that there is a non-living foreign object containing water; otherwise, it is determined that there is no non-living foreign object.

[0055] It should be noted that the above thresholds satisfy the following size relationship: the fourth threshold < the third threshold < the first threshold, and the fifth threshold < the second threshold, to ensure that the judgment intervals of metallic foreign objects and water-containing non-living foreign objects do not overlap.

[0056] The above technical solution, by measuring the equivalent series resistance and equivalent series inductance through multi-frequency sweep measurement, and calculating the resistance fitting index k and the relative change rate of inductance ΔL / L, effectively distinguishes between metallic foreign objects and water-containing non-living foreign objects. It solves the technical problem that existing technologies cannot distinguish between non-living foreign object types, and completely reuses existing hardware without adding any sensors.

[0057] In one possible embodiment, during normal power transmission of the wireless charging system, the vehicle may have already started charging, but foreign objects such as leaves, metal fragments, or small animals may still enter the charging area. To ensure safety during the charging process, this embodiment provides a dynamic monitoring mechanism. The monitoring method includes: during the power transmission of the wireless charging system, applying a detection signal to the transmitting coil using a power transmission gap to measure the equivalent series resistance of the transmitting coil; comparing the currently measured equivalent series resistance with a reference value recorded before charging started; and when the change in the equivalent series resistance exceeds a sixth threshold, determining that a foreign object has entered the charging area during the charging process, interrupting power transmission, and issuing an alarm signal.

[0058] Specifically, the transmitter controller utilizes the natural gaps in power transmission for detection. These power transmission gaps refer to short pauses during the power transmission process, such as the transition period between constant current charging and constant voltage charging, the transient pause during inverter switching frequency adjustment, or the idle time slots between wireless power transmission protocol frames. During these gaps, power transmission is temporarily interrupted, allowing the transmitter controller to insert detection signals without affecting the normal charging process.

[0059] During detection, the transmitter controller applies a short-duration detection signal to the transmitter coil, such as a low-power excitation signal at a single frequency of 1MHz, to quickly measure the equivalent series resistance of the transmitter coil. The real-time measurement value is compared with a reference value recorded before charging begins to calculate the resistance change. If the resistance change exceeds a sixth threshold, it indicates that a foreign object has entered the charging area during charging. The transmitter controller immediately interrupts power transmission and issues an alarm signal. The sixth threshold is a preset value used to determine whether the change in equivalent series resistance meets the foreign object entry standard; its specific value can be calibrated according to system design, measurement accuracy, and safety requirements.

[0060] For example, under normal, foreign object-free conditions, the equivalent series resistance of the transmitting coil is at least 0.3Ω. When a thin metal sheet enters the charging area, the equivalent series resistance may rise to 0.36Ω, a change of 0.06Ω; when a small animal enters, the equivalent series resistance may rise to 0.33Ω, a change of 0.03Ω. To ensure sensitivity while avoiding misjudgments caused by environmental noise, the sixth threshold can be set to 10% of the reference value, i.e., 0.03Ω.

[0061] At this point, if the measured resistance is 0.34Ω and the resistance change is 0.04Ω exceeding 0.03Ω, it is determined that a foreign object has entered, and charging is immediately interrupted; if the measured resistance is 0.31Ω and the change is 0.01Ω not exceeding the threshold, it is determined that there is no abnormality, and normal charging continues. The sixth threshold can be flexibly adjusted according to different vehicle models, different charging power levels, and different safety level requirements. For example, it can be set to 5% in high-safety-level scenarios and 15% in general scenarios.

[0062] This technical solution utilizes the natural gap in power transmission to insert a detection signal and monitor the change in the equivalent series resistance of the transmitting coil in real time. By comparing it with the reference value before charging starts, when the change exceeds a preset threshold, it immediately determines that a foreign object has entered and interrupts charging. This mechanism achieves safety protection throughout the charging process, making up for the shortcomings of detection only before start-up. Even if a foreign object enters during charging, it can be detected and dealt with in time, effectively avoiding safety accidents caused by the heat generated by the foreign object. Moreover, it completely reuses existing hardware without the need to add any additional sensors.

[0063] Based on the same inventive concept, embodiments of this application also provide a wireless charging foreign object detection device. For example... Figure 3 The diagram shown is a structural schematic of a wireless charging foreign object detection device, which may include: The transmitting module 301 is used to control the transmitting end to apply a low-power AC excitation signal to the transmitting coil before the wireless charging system starts power transmission; Measurement module 302 is used to measure the port impedance parameters of the transmitting coil multiple times at a fixed sampling rate within a continuous time window to obtain a time series of impedance parameters; Transformation module 303 is used to perform Fourier transform on the time series to obtain the power spectral density distribution; The detection module 304 detects the type of foreign object based on the feature information associated with the type of foreign object in the power spectral density distribution.

[0064] In one possible embodiment, the transmitting module 301 is further configured to: control the transmitting end to send a detection command to the receiving end via wireless communication; wherein, after receiving the detection command, the receiving end will electrically isolate the receiving coil from the battery load and send an acknowledgment reply to the transmitting end, the acknowledgment reply being used to indicate that the receiving end is in an open circuit state; after receiving the acknowledgment reply, a low-power AC excitation signal is applied to the transmitting coil.

[0065] In one possible embodiment, the measurement module 302 is used to: set the duration of a continuous time window so that it covers at least multiple physiological activity cycles; wherein the physiological activity cycle characterizes the periodic physiological rhythm of a living organism due to heartbeat and / or respiration; within the continuous time window, sequentially collect port impedance parameters at each sampling time according to a fixed sampling rate; and arrange the port impedance parameters in chronological order to form a time series of impedance parameters.

[0066] In one possible embodiment, the transformation module 303 is configured to: determine the number of transformation points of the Fourier transform based on the number of sampling points of the time series, so that the Fourier transform can distinguish the frequency components of the physiological activities of living organisms; perform a Fourier transform on the time series according to the number of transformation points to obtain the complex spectrum of the time series at discrete frequency points; calculate the squared value or amplitude of each complex spectrum, and use the squared value or amplitude as the power spectral density value at the corresponding frequency point to obtain the power spectral density distribution.

[0067] In one possible embodiment, the detection module 304 is used to: detect whether the power spectral density distribution meets the following conditions: there is a spectral component corresponding to the frequency range of physiological activities of a living organism, and the amplitude of the spectral component exceeds a preset amplitude; if so, it is determined that there is a living organism foreign body; if not, it is determined whether there is a non-living foreign body and the type of non-living foreign body based on the trend of impedance parameter change with frequency.

[0068] In one possible embodiment, the detection module 304 is configured to: apply at least two low-power excitation signals of different frequencies to the transmitting coil, measure the equivalent series resistance and equivalent series inductance at each frequency; calculate the fitting exponent of the equivalent series resistance as a function of frequency, and the relative rate of change of the equivalent series inductance between the lowest and highest frequencies; determine the presence of a metallic foreign object when the fitting exponent is greater than a first threshold and the relative rate of change is greater than a second threshold; determine the presence of a water-containing non-living foreign object when the fitting exponent is between a third threshold and a fourth threshold and the relative rate of change is less than a fifth preset threshold; wherein the first threshold is greater than the third threshold, the third threshold is greater than the fourth threshold, and the fifth threshold is less than the second threshold; otherwise, determine that no non-living foreign object exists.

[0069] In one possible embodiment, the device further includes: an alarm module, used to apply a detection signal to the transmitting coil during the power transmission gap of the wireless charging system to measure the equivalent series resistance of the transmitting coil; compare the currently measured equivalent series resistance with a reference value recorded before charging starts; when the change in the equivalent series resistance exceeds a sixth threshold, determine that a foreign object has entered the charging area during the charging process, then interrupt the power transmission and issue an alarm signal.

[0070] In the implementation of this application, the technical effects achieved by the device can be referred to the aforementioned method section, and will not be repeated here.

[0071] Based on the same inventive concept, this application also provides an electronic device that can realize the function of the aforementioned wireless charging foreign object detection method device. (Refer to...) Figure 4 Electronic devices include: At least one processor 401 and a memory 402 connected to at least one processor 401. In this embodiment, the specific connection medium between the processor 401 and the memory 402 is not limited. Figure 4 The example shown is the connection between processor 401 and memory 402 via bus 400. Bus 400 is... Figure 4 The connections between other components are indicated by thick lines and are for illustrative purposes only, not as limiting information. The 400 bus can be divided into address bus, data bus, control bus, etc., for ease of representation. Figure 4 The term is represented by a single thick line, but this does not imply that there is only one bus or one type of bus. Alternatively, processor 401 can also be called a controller; there is no restriction on the name.

[0072] In this embodiment, the memory 402 stores instructions executable by at least one processor 401. By executing the instructions stored in the memory 402, the at least one processor 401 can execute the wireless charging foreign object detection method described above. The processor 401 can implement... Figure 3 The functions of each module in the device shown.

[0073] The processor 401 is the control center of the device. It can connect to various parts of the control device through various interfaces and lines. By running or executing instructions stored in memory 402 and calling data stored in memory 402, it can realize various functions of the device and process data, thereby performing overall monitoring of the device.

[0074] In one possible design, processor 401 may include one or more processing units. Processor 401 may integrate an application processor and a modem processor, wherein the application processor mainly handles the operating system, user interface, and applications, and the modem processor mainly handles wireless communication. It is understood that the modem processor may also not be integrated into processor 401. In some embodiments, processor 401 and memory 402 may be implemented on the same chip; in some embodiments, they may also be implemented separately on separate chips.

[0075] Processor 401 can be a general-purpose processor, such as a central processing unit (CPU), digital signal processor, application-specific integrated circuit, field-programmable gate array or other programmable logic device, discrete gate or transistor logic device, or discrete hardware component, capable of implementing or executing the methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the wireless charging foreign object detection method disclosed in the embodiments of this application can be directly manifested as being executed by a hardware processor, or being executed by a combination of hardware and software modules within the processor.

[0076] Memory 402, as a non-volatile computer-readable storage medium, can be used to store non-volatile software programs, non-volatile computer-executable programs, and modules. Memory 402 may include at least one type of storage medium, such as flash memory, hard disk, multimedia card, card-type memory, random access memory (RAM), static random access memory (SRAM), programmable read-only memory (PROM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), magnetic storage, magnetic disk, optical disk, etc. Memory 402 can be any other medium capable of carrying or storing desired program code in the form of instructions or data structures that can be accessed by a computer, but is not limited thereto. In the embodiments of this application, memory 402 can also be a circuit or any other device capable of implementing storage functions for storing program instructions and / or data.

[0077] By designing and programming the processor 401, the code corresponding to the wireless charging foreign object detection method described in the foregoing embodiments can be embedded into the chip, thereby enabling the chip to execute the code during operation. Figure 1 The steps of the wireless charging foreign object detection method of the illustrated embodiment are described below. How to design and program the processor 401 is a technique well-known to those skilled in the art and will not be elaborated upon here.

[0078] Based on the same inventive concept, embodiments of this application also provide a storage medium storing computer instructions that, when executed on a computer, cause the computer to perform the wireless charging foreign object detection method described above.

[0079] In some possible implementations, various aspects of the wireless charging foreign object detection method provided in this application can also be implemented in the form of a program product, which includes program code. When the program product is run on a device, the program code is used to cause the control device to perform the steps in the wireless charging foreign object detection method according to the various exemplary embodiments of this application described above.

[0080] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0081] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems) according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0082] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0083] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0084] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A wireless charging foreign object detection method, characterized by, The method comprises: controlling the transmitting end to apply a low-power alternating excitation signal to the transmitting coil before the wireless charging system starts power transmission; setting the length of the continuous time window to cover at least a plurality of physiological activity cycles, wherein the physiological activity cycle represents the periodic physiological rhythm generated by the living organism due to heartbeat and / or respiration; in the continuous time window, collecting port impedance parameters at each sampling time according to a fixed sampling rate, and arranging the port impedance parameters in time sequence to form a time sequence; performing Fourier transform on the time sequence to obtain a power spectral density distribution; detecting the type of foreign matter based on characteristic information associated with the type of foreign matter in the power spectral density distribution.

2. The method of claim 1, wherein, Before the control of the transmitting end to apply a low-power alternating excitation signal to the transmitting coil, the method further comprises: controlling the transmitting end to send a detection instruction to the receiving end through wireless communication; wherein after receiving the detection instruction, the receiving end will electrically isolate the receiving coil from the battery load, and send an acknowledgement reply to the transmitting end, which is used to indicate that the receiving end is in an open circuit state; after receiving the acknowledgement reply, applying the low-power alternating excitation signal to the transmitting coil.

3. The method of claim 1, wherein, The Fourier transform on the time sequence to obtain a power spectral density distribution comprises: determining the number of transform points of the Fourier transform based on the number of sampling points of the time sequence, so that the Fourier transform can distinguish the physiological activity frequency component of the living organism; performing the Fourier transform on the time sequence according to the number of transform points to obtain the complex spectrum of the time sequence at discrete frequency points; calculating the amplitude square value or amplitude of each complex spectrum, and taking the amplitude square value or amplitude as the power spectral density value at the corresponding frequency point to obtain the power spectral density distribution.

4. The method of claim 1, wherein, The detection of the type of foreign matter based on the characteristic information associated with the type of foreign matter in the power spectral density distribution comprises: detecting whether the power spectral density distribution satisfies the following condition: there is a frequency spectrum component corresponding to the physiological activity frequency range of the living organism, and the amplitude of the frequency spectrum component exceeds a preset amplitude; if yes, it is determined that there is a living organism foreign matter; if not, based on the change trend of the impedance parameter with frequency, it is determined whether there is a non-living foreign matter and the type of the non-living foreign matter.

5. The method of claim 4, wherein, The determination of whether there is a non-living foreign matter and the type of the non-living foreign matter based on the change trend of the impedance parameter with frequency comprises: applying at least two low-power excitation signals of different frequencies to the transmitting coil to measure the equivalent series resistance and the equivalent series inductance at each frequency; calculating the fitting index of the equivalent series resistance with frequency and the relative change rate of the equivalent series inductance between the lowest frequency and the highest frequency; when the fitting index is greater than a first threshold and the relative change rate is greater than a second threshold, it is determined that there is a metal foreign matter; When the fitting index is between a third threshold value and a fourth threshold value and the relative change rate is less than a fifth preset threshold value, it is determined that there is a water-containing non-living foreign matter; wherein the first threshold value is greater than the third threshold value, the third threshold value is greater than the fourth threshold value, and the fifth threshold value is less than the second threshold value; Otherwise, it is determined that there is no non-living foreign matter.

6. The method of claim 1, wherein, Further comprising: During the power transmission process of the wireless charging system, a detection signal is applied to the transmitting coil using a power transmission gap to measure the equivalent series resistance of the transmitting coil; The currently measured equivalent series resistance is compared with a reference value recorded before the start of charging; When the change amount of the equivalent series resistance exceeds a sixth threshold value, it is determined that a foreign matter has entered the charging area during the charging process, and the power transmission is interrupted and an alarm signal is sent. 7.A wireless charging foreign object detection device, characterized by, Comprising: The transmitting module is configured to control the transmitting end to apply a low-power alternating excitation signal to the transmitting coil before the wireless charging system starts power transmission; The measurement module is configured to set the length of the continuous time window to cover at least a plurality of physiological activity periods; wherein the physiological activity period represents a periodic physiological rhythm generated by heartbeat and / or breathing of a living organism; within the continuous time window, the port impedance parameters at each sampling time are sequentially collected according to a fixed sampling rate, and the port impedance parameters are arranged in chronological order to form a time series; The transformation module is configured to perform Fourier transform on the time series to obtain a power spectral density distribution; The detection module detects the foreign matter type based on the characteristic information associated with the foreign matter type in the power spectral density distribution.

8. An electronic device, comprising: It comprises a processor and a memory, wherein the memory stores program code, and when the program code is executed by the processor, the processor executes the method of any one of claims 1-6.

9. A computer-readable storage medium, characterized in that, The program code is used to make the electronic device execute the method of any one of claims 1-6 when the storage medium is running on the electronic device.

Images