Foreign matter recognition method and system for wireless charging area

Abstract

The present application relates to the technical field of wireless power transmission, and specifically discloses a foreign matter identification method and system for a wireless charging area, which first installs ultrasonic sensors, light sensors and imaging modules on a wireless charging parking space, and then uses the ultrasonic sensors, light sensors and imaging modules to detect and identify foreign matters in the wireless charging area of the wireless charging parking space. The present application combines image processing technology and uses a neural network model to identify the types of foreign matters, which can have high foreign matter identification accuracy, can accurately distinguish whether the foreign matter in the wireless charging area is a metal foreign matter, a biological foreign matter or other foreign matter, and can mark the positions of the foreign matters, and can be combined with a foreign matter removal device, method and power control method for application.

Description

Technical Field

[0001] This invention relates to the field of wireless power transmission technology, and more particularly to a method for identifying foreign objects in a wireless charging area. Background Technology

[0002] Wireless power transfer (WPT) is a technology that integrates power electronics and automatic control theories and technologies to enable the loosely coupled, non-electrically contactless transmission of electrical energy between the power grid (or battery) and electrical devices via a medium (such as an electric field, magnetic field, microwave, or laser). Compared to traditional electrical contact-based power access technologies, wireless power transfer offers advantages such as higher reliability and security, smaller footprint, flexible usage, less susceptibility to external environmental interference, strong grid interaction capabilities, and applicability in certain extreme environments and special conditions. Therefore, it is finding increasingly widespread development and application in consumer electronics, healthcare, electric vehicles, and other fields.

[0003] Magnetic field-coupled wireless power transfer uses a high-frequency alternating current in the transmitting coil to generate a high-frequency alternating magnetic field, which serves as the carrier for power transmission. However, when metallic foreign objects (such as coins, keys, paper clips, tin foil, coated aluminum foil lunch boxes, or mobile phones) appear in or around the transmitting coil of the MC-WPT system (wireless charging area), they will alter the distribution of the high-frequency alternating magnetic field, leading to a decrease in system transmission efficiency. Furthermore, metallic foreign objects can generate heat due to eddy current effects and hysteresis losses, posing a safety hazard. Therefore, detection technology for metallic foreign objects is indispensable to ensure the safe operation and efficiency of the MC-WPT system. In real life, other types of foreign objects, such as living organisms, may enter the wireless charging area. Excessive temperatures in the wireless charging area (e.g., too close to metallic foreign objects, abnormal temperature rise in the chassis of electric vehicles) may burn living organisms, causing them to jump around erratically, potentially damaging the wireless charging system and endangering others. Other foreign objects, such as plastic and paper scraps, especially plastic, can pose safety hazards due to high temperatures (close to metallic foreign objects) (melting, emitting unpleasant odors). Therefore, identifying the types of these three foreign objects is crucial.

[0004] Current foreign object identification methods primarily target metallic or biological foreign objects. Metallic foreign objects can be identified by setting up a foreign object detection coil and measuring its impedance change to determine the presence of a metallic foreign object. An array of detection coils can pinpoint the object's location. However, this method only identifies metallic foreign objects and cannot detect biological or other types of foreign objects. For foreign object identification where both biological and metallic foreign objects are present, a combination of infrared sensors and detection coils is often used. This method is simple but cannot identify other types of foreign objects. Current research mainly focuses on identifying metallic and biological foreign objects, lacking coverage for other types of foreign objects. Summary of the Invention

[0005] This invention provides a method and system for identifying foreign objects in a wireless charging area, and solves the technical problem of how to accurately identify the type of foreign object in a wireless charging area.

[0006] To address the above technical problems, this invention provides a method for foreign object identification in a wireless charging area, comprising the following steps:

[0007] S1. Install one or more ultrasonic sensors aligned with the wireless charging area in the wireless charging parking space; install two or more light sensors on the four sides of the wireless charging area in the wireless charging parking space; install a retractable and rotatable imaging module under the ground at the center of the wireless charging area in the wireless charging parking space. When the imaging module is working, the imaging module extends out of the ground to a preset height, and when the imaging module is finished working, the imaging module retracts under the ground; the imaging module includes an infrared thermal imager and a camera.

[0008] S2. The ultrasonic sensor, the light sensor, and the imaging module are used to detect and identify foreign objects in the wireless charging area of ​​the wireless charging parking space.

[0009] Furthermore, step S2 specifically includes the following steps:

[0010] S21. Use an ultrasonic sensor to detect the wireless charging area and determine whether there are foreign objects in the wireless charging area. If so, proceed to step S22; otherwise, continue the detection.

[0011] S22. Determine whether there is a foreign object in the center of the wireless charging area based on the detection signal of the ultrasonic sensor. If so, rotate the imaging module at a fixed speed to remove the foreign object in the center using centrifugal force. After stopping the rotation, wait for a preset time period and then proceed to step S23. Otherwise, proceed directly to step S24.

[0012] S23. Use an ultrasonic sensor to detect the wireless charging area and determine whether the foreign object in the wireless charging area is no longer there. If it is no longer there, return to step S21. If there is a foreign object in the area outside the center of the wireless charging area, proceed to step S24. If there is still a foreign object in the center of the wireless charging area, return to step S21.

[0013] S24. Four light sensors are used to obtain the light intensity on the current wireless charging area, and the shooting mode of the camera is set according to the light intensity. When the light intensity of all light sensors is less than the preset light intensity threshold, the shooting mode of the camera is set to night mode, and otherwise to day mode.

[0014] S25. The infrared thermal imager is used to take pictures of the wireless charging area to obtain thermal images, and the camera is used to take pictures of the wireless charging area to obtain physical images.

[0015] S26. Identify the type of foreign object based on the thermal imaging image and the physical object image.

[0016] Further, in step S25, the infrared thermal imager is used to take pictures of the wireless charging area to obtain thermal images, specifically including the following steps:

[0017] Extend the imaging module out of the ground at a predetermined height;

[0018] By rotating the imaging module one full turn, the infrared thermal imager captures images of the wireless charging area from different angles, obtaining raw thermal images.

[0019] Identify the wireless charging area border in each original thermal imaging frame, and crop out the area outside the wireless charging area border to obtain a clean thermal imaging frame.

[0020] The clean frames from each thermal imaging image are fused to obtain a thermal image of the wireless charging area.

[0021] Further, in step S25, the camera is used to take a picture of the wireless charging area to obtain a real-world image, specifically including the following steps:

[0022] During the rotation of the imaging module, the camera captures images of the wireless charging area from different angles, obtaining the original frames of the physical object.

[0023] Identify the border of the wireless charging area in each original frame of the object, and crop out the area outside the border of the wireless charging area to obtain the clean frame of the object.

[0024] The clean frames of each object are fused together to obtain a physical image of the wireless charging area.

[0025] Further, step S26 specifically includes:

[0026] The thermal imaging image from the previous moment and the image of the object from the current moment are input into the trained foreign object classification model. The foreign object classification model outputs the corresponding foreign object type and marks the location of each type of foreign object on the image of the object from the current moment.

[0027] Furthermore, the foreign object classification model can classify foreign objects into three categories: metallic foreign objects, biological foreign objects, and other foreign objects. During the training of the foreign object classification model, the dataset samples used are the thermal imaging images and the actual object images generated under the same environment, in which the location and type of foreign objects are labeled.

[0028] This invention also provides a foreign object identification system for a wireless charging area, the key feature of which is that it includes one or more ultrasonic sensors, two or more light sensors, a retractable imaging module, and a control module connecting the ultrasonic sensors, the light sensors, and the imaging module; the ultrasonic sensors are installed in the wireless charging parking space and aligned with the wireless charging area; the light sensors are installed on the four sides of the wireless charging area; the imaging module is installed below the ground at the center of the wireless charging area in the wireless charging parking space, and when the imaging module is working, it extends above the ground to a preset height, and when the imaging module is finished working, it retracts below the ground; the imaging module includes an infrared thermal imager and a camera;

[0029] The control module is used to perform foreign object detection and identification in the wireless charging area of ​​the wireless charging parking space using the ultrasonic sensor, the light sensor, and the imaging module.

[0030] Specifically, the process by which the control module uses the ultrasonic sensor, the light sensor, and the imaging module to detect and identify foreign objects in the wireless charging area of ​​the wireless charging parking space is as described in step S2 above.

[0031] The foreign object identification method and system for wireless charging areas provided by this invention utilizes the ultrasonic sensor, the light sensor, and the imaging module to detect and identify foreign objects in the wireless charging area of ​​a wireless charging parking space. Specifically:

[0032] First, an ultrasonic sensor is used to perform a preliminary detection of foreign objects (i.e., step S21). If a foreign object is found, proceed to the next step to avoid directly starting the more complex foreign object identification work later, which would waste computing resources and power consumption.

[0033] Before foreign object detection, since the imaging module is installed under the ground at the center of the wireless charging area, it is necessary to ensure that there are no foreign objects at the center of the wireless charging area. Therefore, step S22 is used to perform foreign object detection again. If there are foreign objects at the center, the imaging module is rotated at a fixed speed (high) to remove the foreign objects at the center by using a large centrifugal force. This method of using centrifugal force will not damage the foreign objects and the removal effect is good. However, this method may remove the foreign objects outside the center but still in the center of the wireless charging area, so it is necessary to detect foreign objects again (step S23).

[0034] When a foreign object is detected again outside the center, the light sensor is used to obtain the light intensity on the current wireless charging area, and the camera's shooting mode is adjusted according to the light intensity (step S24) to ensure that the captured images are clear and have high image quality, which helps to ensure the accuracy of foreign object type identification in step S26.

[0035] Next, an infrared thermal imager is used to acquire thermal images, and a camera with a pre-set mode is used to take photos of the object (step S25). Finally, the two photos are combined and a neural network model is used to identify the type of foreign object (step S26), which can achieve high accuracy in foreign object identification.

[0036] This invention employs an ultrasonic sensor, a camera, a light sensor, and an infrared thermal imager, combined with image processing technology, and uses a neural network model to identify foreign objects. It can achieve high foreign object identification accuracy and can accurately distinguish whether a foreign object entering the wireless charging area is a metallic foreign object, a biological foreign object, or another type of foreign object. It can also mark the location of each foreign object and can be combined with foreign object removal devices, methods, power control methods, etc. Attached Figure Description

[0037] Figure 1 This is a flowchart of the foreign object identification method in the wireless charging area provided in Embodiment 1 of the present invention;

[0038] Figure 2 This is a schematic diagram showing the installation positions of the ultrasonic sensor, light sensor, and imaging module provided in Embodiment 1 of the present invention;

[0039] Figure 3 This is a structural diagram of a foreign object identification system for a wireless charging area provided in Embodiment 2 of the present invention;

[0040] Figure 4 This is a flowchart of the wireless power transmission power reduction operation method based on foreign object identification for temperature rise protection provided in Embodiment 3 of the present invention.

[0041] Figure reference numerals: 11-ultrasonic sensor, 12-light sensor, 13-imaging module, 14-control module. Detailed Implementation

[0042] The embodiments of the present invention are described in detail below with reference to the accompanying drawings. The embodiments are given for illustrative purposes only and should not be construed as limiting the present invention. The accompanying drawings are for reference and illustration only and do not constitute a limitation on the scope of patent protection of the present invention, because many changes can be made to the present invention without departing from the spirit and scope of the present invention.

[0043] Example 1

[0044] This invention provides a method for foreign object identification in a wireless charging area, such as... Figure 1 The flowchart shown includes the steps;

[0045] S1. Install one or more ultrasonic sensors 11 aligned with the wireless charging area in the wireless charging parking space; install two or more light sensors 12 on the four sides of the wireless charging area in the wireless charging parking space; install a retractable and rotatable imaging module 13 under the ground at the center of the wireless charging area in the wireless charging parking space. When the imaging module 13 is working, the imaging module 13 extends out of the ground to a preset height. When the imaging module 13 is finished working, the imaging module 13 retracts under the ground. The imaging module 13 includes an infrared thermal imager and a camera.

[0046] S2. The ultrasonic sensor 11, the light sensor 12, and the imaging module 13 are used to detect and identify foreign objects in the wireless charging area of ​​the wireless charging parking space.

[0047] (1) Regarding step S1

[0048] For ease of explanation, such as Figure 2 As shown in the top view of the parking space, this example is equipped with two ultrasonic sensors 11, one on each side of the parking space's curb. In wireless charging of electric vehicles, the wireless charging area is mostly marked as a rectangle, and four light sensors 12 are provided, each installed at the midpoint of one of the four edges of the rectangular wireless charging area. The extension and retraction of the imaging module 13 can be achieved using a corresponding motor and telescopic rod.

[0049] (1) Regarding step S2

[0050] like Figure 1 As shown in the flowchart, step S2 specifically includes the following steps:

[0051] S21. Use ultrasonic sensor 11 to detect the wireless charging area and determine whether there are foreign objects in the wireless charging area. If there are, proceed to step S22; otherwise, continue the detection.

[0052] S22. Determine whether there is a foreign object in the center of the wireless charging area based on the detection signal of the ultrasonic sensor 11. If so, rotate the imaging module 13 at a fixed speed to remove the foreign object in the center using centrifugal force. After stopping the rotation, wait for a preset time period and then proceed to step S23. Otherwise, proceed directly to step S24.

[0053] S23. Use ultrasonic sensor 11 to detect the wireless charging area and determine whether the foreign object in the wireless charging area is no longer there. If it is no longer there, return to step S21. If there is a foreign object in the area outside the center of the wireless charging area, proceed to step S24. If there is still a foreign object in the center of the wireless charging area, return to step S21.

[0054] S24. Four light sensors 12 are used to obtain the light intensity on the current wireless charging area, and the shooting mode of the camera is set according to the light intensity. When the light intensity of all light sensors 12 is less than the preset light intensity threshold, the shooting mode of the camera is set to night mode, and otherwise to day mode.

[0055] S25. The infrared thermal imager is used to take pictures of the wireless charging area to obtain thermal images, and the camera is used to take pictures of the wireless charging area to obtain physical images.

[0056] S26. Identify the type of foreign object based on the thermal imaging image and the physical object image.

[0057] In this example, the ultrasonic sensor 11 is first used to perform preliminary detection of foreign objects (i.e., step S21). If foreign objects are found, the next step is performed to avoid directly starting the more complex foreign object identification work later, which would waste computing resources and power consumption.

[0058] Before foreign object identification, since the imaging module 13 is installed under the ground at the center of the wireless charging area, it is necessary to ensure that there are no foreign objects at the center of the wireless charging area. Therefore, step S22 is used to perform another foreign object detection. Steps S22 and S21 can be omitted as one step. That is, only one detection is needed using an ultrasonic sensor to know whether there are foreign objects at the center of the wireless charging area and whether there are foreign objects in the entire wireless charging area.

[0059] If there is a foreign object in the center, the imaging module 13 is rotated at a fixed speed (high) to remove the foreign object in the center by using a large centrifugal force. This method of using centrifugal force will not damage the foreign object and the removal effect is good. However, this method may remove the foreign object outside the center but still in the center of the wireless charging area, so it is necessary to detect the foreign object again (step S23).

[0060] If a foreign object is detected again outside the center, the light sensor is used to obtain the light intensity on the current wireless charging area. The camera's shooting mode is adjusted according to the light intensity to ensure that the captured images are clear and of high quality, which helps to ensure the accuracy of foreign object identification in step S26.

[0061] Next, an infrared thermal imager is used to acquire thermal images, and a camera with a pre-set mode is used to take photos of the object. Finally, the two types of photos are combined and a neural network model is used to identify the type of foreign object, which can achieve high accuracy in foreign object identification.

[0062] Specifically, in step S25, the infrared thermal imager is used to take pictures of the wireless charging area to obtain thermal images, which specifically includes the following steps:

[0063] Extend the imaging module 13 out of the ground at a predetermined height;

[0064] By rotating the imaging module 13 one revolution, the infrared thermal imager captures the wireless charging area at different angles to obtain the original thermal image frame.

[0065] Identify the wireless charging area border in each original thermal imaging frame, and crop out the area outside the wireless charging area border to obtain a clean thermal imaging frame.

[0066] The clean frames from each thermal imaging image are fused to obtain a thermal image of the wireless charging area.

[0067] Considering the limited shooting angle of the infrared thermal imager and the limited extension height of the imaging module 13, this example adopts an image fusion method to ensure the quality of the thermal imaging images.

[0068] Specifically, in step S25, the camera is used to take a picture of the wireless charging area to obtain a real-world image, which includes the following steps:

[0069] During the rotation of the imaging module 13, the camera captures images of the wireless charging area from different angles to obtain the original frames of the physical object.

[0070] Identify the border of the wireless charging area in each original frame of the object, and crop out the area outside the border of the wireless charging area to obtain the clean frame of the object.

[0071] The clean frames of each object are fused together to obtain a physical image of the wireless charging area.

[0072] Considering the limited shooting angle of the camera and the limited extension height of the imaging module 13, this example uses image fusion to ensure the quality of the physical image.

[0073] It should be noted that the infrared thermal imager and the camera are turned on simultaneously and have the same sampling frequency, so the generated thermal images and the actual images correspond highly in time.

[0074] Step S26 specifically involves:

[0075] The thermal imaging image from the previous moment and the image of the object from the current moment are input into the trained foreign object classification model. The foreign object classification model outputs the corresponding foreign object type and marks the location of each type of foreign object on the image of the object from the current moment.

[0076] The foreign object classification model can classify foreign objects into three categories: metallic foreign objects, biological foreign objects, and other foreign objects. In the process of training the foreign object classification model, the dataset samples used are the thermal imaging images and the actual object images generated under the same environment, in which the location and type of foreign objects are marked.

[0077] This example uses a neural network for foreign object identification. By collecting and processing the dataset, building the network and designing the parameters, training the model, optimizing the parameters and testing them, high classification accuracy and fast classification speed can be obtained. The trained neural network is directly deployed in the control module 14.

[0078] It should also be noted that, such as Figure 2 As shown, in order to install the imaging module 13 under the ground at the center of the wireless charging area, the center of the primary side transmitting coil, the primary side magnetic core, and the primary side magnetic shielding plate all need to be hollowed out. In addition, in order to install the telescopic mechanism, it is also necessary to dig to a corresponding depth underground.

[0079] This invention provides a method for foreign object identification in a wireless charging area. It employs an ultrasonic sensor 11, a camera, a light sensor 12, and an infrared thermal imager, combined with image processing technology and a neural network model for foreign object identification. This method achieves high accuracy in identifying foreign objects, accurately distinguishing whether they are metallic, biological, or other types. It can also mark the location of each foreign object, allowing parking garage managers to target and remove them based on their type and location. This foreign object identification method can be integrated with other aspects of the wireless charging system design to achieve higher-quality control.

[0080] Example 2

[0081] Corresponding to Embodiment 1, this embodiment provides a foreign object identification system for a wireless charging area, such as... Figure 3 As shown, the device includes one or more ultrasonic sensors 11, two or more light sensors 12, a retractable imaging module 13, and a control module 14 connecting the ultrasonic sensors 11, the light sensors 12, and the imaging module 13. The ultrasonic sensors 11 are installed in the wireless charging parking space and aligned with the wireless charging area. The light sensors 12 are installed on the four sides of the wireless charging area. The imaging module 13 is installed under the ground at the center of the wireless charging area of ​​the wireless charging parking space. When the imaging module 13 is working, it extends out of the ground to a preset height. When the imaging module 13 is finished working, it retracts under the ground. The imaging module 13 includes an infrared thermal imager and a camera.

[0082] The control module 14 is used to perform foreign object detection and identification on the wireless charging area of ​​the wireless charging parking space using the ultrasonic sensor 11, the light sensor 12, and the imaging module 13.

[0083] The specific process by which the control module 14 uses the ultrasonic sensor 11, the light sensor 12, and the imaging module 13 to perform foreign object detection and identification in the wireless charging area of ​​the wireless charging parking space is as described in step S2 of Embodiment 1.

[0084] The control module 14 here can directly use the MCU of the primary side transmitter.

[0085] Further descriptions of the ultrasonic sensor 11, the light sensor 12, and the imaging module 13 are as shown in Embodiment 1, and will not be repeated in this embodiment.

[0086] Example 3

[0087] To illustrate the crucial role of foreign object detection in wireless charging systems, this embodiment presents a specific application: combining foreign object detection and identification with temperature rise control to provide a wireless power transfer power reduction operation method based on foreign object detection for temperature rise protection. Figure 4 As shown, the method includes the following steps:

[0088] N1. During wireless charging, detect whether there are foreign objects in the wireless charging area. If not, continue to detect. If so, identify the foreign object category and output all foreign object types. The foreign object category identification classifies foreign objects into three categories: metallic foreign objects, biological foreign objects, and other foreign objects other than metallic foreign objects and biological foreign objects.

[0089] N2. Set the desired temperature for each type of foreign object based on all the types of foreign objects output and the distance between each type of foreign object;

[0090] N3. Activate temperature detection to obtain the actual highest temperature value of various foreign objects;

[0091] N4. Determine whether the actual maximum temperature of each type of foreign object is less than its corresponding expected temperature. If yes, return to step N1; otherwise, proceed to step N5.

[0092] N5. Determine whether the foreign object contains a metallic foreign object. If so, adjust the AC-DC converter of the wireless power transmission system to reduce the system power and return to step N3; otherwise, cut off the power transmission.

[0093] In step N2:

[0094] If the identified foreign object type contains only metallic foreign objects, the expected temperature of the metallic foreign objects is set to T1;

[0095] If the identified foreign object type contains only biological foreign objects, the expected temperature of the biological foreign objects is set to T2;

[0096] If the identified foreign object type contains only other foreign objects, the expected temperature of the other foreign objects is set to T3;

[0097] If the identified foreign object types include both metallic and biological foreign objects, the expected temperature for metallic foreign objects is set to T4, and the expected temperature for biological foreign objects is set to T5. T4 and T5 satisfy the following conditions:

[0098] T4=α1(1-β1)T1

[0099] T5=(1-β1)T2

[0100] Where α1 represents the influence coefficient of the biological foreign body on T2, and α2 represents the shortest distance D between the metallic foreign body and the biological foreign body. min1 The influence coefficient of foreign bodies on organisms;

[0101] If the identified foreign object type contains both metallic and other foreign objects, the expected temperature for the metallic foreign object is set to T6, and the expected temperature for the other foreign objects is set to T7. T6 and T7 satisfy the following conditions:

[0102] T6=α2(1-β2)T1

[0103] T7=(1-β2)T3

[0104] Where α2 represents the influence coefficient of other foreign objects on T6, and β2 represents the shortest distance D between the metallic foreign object and other foreign objects. min2 Influence coefficient on other foreign objects;

[0105] If the identified foreign object types include metallic foreign objects, biological foreign objects, and other foreign objects, the expected temperature for metallic foreign objects is set to T8, the expected temperature for biological foreign objects is set to T9, and the expected temperature for other foreign objects is set to T. 10 T8, T9, T 10 satisfy:

[0106] T8=α3(1-β3)(1-β4)T1

[0107] T9=(1-β3)T2

[0108] T10=(1-β4)T3

[0109] Wherein, α3 represents the influence coefficient of the biological foreign body and other foreign bodies on T8 when all three types of foreign bodies are present, and β3 represents the shortest distance D between the metallic foreign body and the biological foreign body when all three types are present. min3 The influence coefficient of foreign bodies on organisms, β4, represents the shortest distance D between the metallic foreign body and other foreign bodies when all three are present. min4 Influence coefficient on other foreign objects;

[0110] If the identified foreign object types include both biological foreign objects and other foreign objects, the expected temperature for biological foreign objects is set to T2, and the expected temperature for other foreign objects is set to T3. Generally, 0.8 ≤ α1 ≤ 1, 0.6 ≤ α2 ≤ 0.8, and α3 = α2. Considering that this example is mainly applied to electric vehicle charging, β1, β2, β3, and β4 are set as follows:

[0111]

[0112]

[0113]

[0114]

[0115] When applied to other fields, the values ​​of β1, β2, β3, and β4 may change, depending on the specific application.

[0116] This embodiment takes into account the different temperature requirements of different types of foreign objects, and the fact that metallic foreign objects will generate high temperatures in a magnetic field. If they are too close to biological foreign objects and other foreign objects, it will affect the biological foreign objects and other foreign objects. The desired temperature is set according to different foreign object identification results and the distance between different types of foreign objects. This can reduce power to the minimum while keeping all types of foreign objects at their appropriate temperature during power reduction control.

[0117] In step N2, the ultrasonic sensor 11 is used to measure the distance between various types of foreign objects based on the positions of the foreign object classification model.

[0118] In step N3, the infrared thermal imager is used for temperature detection.

[0119] In step N5, this example uses a PID control process for power regulation. The specific process is as follows:

[0120] Calculate the difference between the temperature of all types of foreign objects and their expected temperature, and find the maximum temperature difference;

[0121] The corresponding control signal is calculated based on the maximum temperature difference and applied to the AC-DC converter using a PID control algorithm.

[0122] The AC-DC converter is connected to the power grid in the front stage, converting the AC to DC. The high-frequency inverter in the back stage converts the DC back to AC. The AC is then transmitted through a resonant network and a transmitting coil to emit a magnetic field.

[0123] In summary, the wireless power transfer reduction method based on foreign object identification for temperature rise protection provided in this invention first detects and identifies foreign objects. Then, it sets a desired temperature for each type of foreign object based on its type and distance from other objects. Next, it obtains the highest actual temperature of each type of foreign object and compares it with the corresponding desired temperature. If both are lower than the desired temperature, there is no safety hazard, and power transfer does not need to be reduced. Conversely, if both are higher, there is a safety hazard, and power transfer needs to be reduced to lower the actual temperature of the metallic foreign object. This process continues until the foreign object is no longer present or the actual temperature of all types of foreign objects is lower than the desired temperature. This invention controls wireless power transfer based on the type and temperature of the foreign object, ensuring maximum power transfer while maintaining safety even when a foreign object is present in the wireless charging area.

[0124] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A foreign object recognition method of a wireless charging area, characterized by, The method comprises the steps of: S1, installing one or more ultrasonic sensors (11) for aligning the wireless charging area on the wireless charging parking space; installing two or more light sensors (12) on the four sides of the wireless charging area of the wireless charging parking space; installing a retractable and rotatable imaging module (13) under the ground at the center of the wireless charging area of the wireless charging parking space; when the imaging module (13) works, the imaging module (13) extends out of the ground by a preset height; when the imaging module (13) completes the work, the imaging module (13) is retracted below the ground; the imaging module (13) comprises an infrared thermal imager and a camera; S2, using the ultrasonic sensor (11), the light sensor (12) and the imaging module (13) to detect and identify foreign matters in the wireless charging area of the wireless charging parking space; The step S2 specifically comprises the steps of: S21, using the ultrasonic sensor (11) to detect the wireless charging area, and determining whether there is a foreign matter in the wireless charging area; if yes, the step S22 is entered; if not, the detection is continued; S22, determining whether there is a foreign matter in the center of the wireless charging area according to the detection signal of the ultrasonic sensor (11); if yes, the imaging module (13) is rotated at a fixed speed to remove the foreign matter in the center by centrifugal force; after the rotation is stopped, a preset time period is waited, and then the step S23 is entered; if not, the step S24 is directly entered; S23, using the ultrasonic sensor (11) to detect the wireless charging area, and determining whether the foreign matter in the wireless charging area has disappeared; if yes, the step S21 is returned to; if not, the step S24 is entered; if the foreign matter still exists in the center of the wireless charging area, the step S21 is returned to; S24, using the four light sensors (12) to obtain the light intensity of the current wireless charging area, and setting the shooting mode of the camera according to the light intensity; when the light intensity of all the light sensors (12) is less than a preset light intensity threshold, the shooting mode of the camera is set to a night mode; otherwise, the shooting mode of the camera is set to a day mode; S25, using the infrared thermal imager to take a photo of the wireless charging area to obtain a thermal imaging picture, and using the camera to take a photo of the wireless charging area to obtain a real object picture; S26, identifying the type of the foreign matter according to the thermal imaging picture and the real object picture. 2.The foreign matter recognition method of a wireless charging area according to claim 1, characterized in that, In the step S25, the infrared thermal imager is used to take a photo of the wireless charging area to obtain a thermal imaging picture, which specifically comprises the steps of: extending the imaging module (13) out of the ground by a preset height; rotating the imaging module (13) for one circle, the infrared thermal imager takes photos of the wireless charging area at different angles to obtain thermal imaging original frames; identifying the frame of the wireless charging area in each thermal imaging original frame, cutting the area outside the frame of the wireless charging area to obtain a thermal imaging pure frame; fusing each thermal imaging pure frame to obtain a thermal imaging picture of the wireless charging area.

3. The foreign object recognition method of a wireless charging area according to claim 2, characterized by, In the step S25, the wireless charging area is photographed to obtain a real object picture by using the camera, and the step specifically includes the following steps: During the rotation of the imaging module (13), the camera photographs the wireless charging area at different angles to obtain a real object original frame; The frame of the wireless charging area is identified in each real object original frame, and the area outside the frame of the wireless charging area is cut to obtain a real object pure frame; Each real object pure frame is fused to obtain a real object picture of the wireless charging area.

4. The foreign object recognition method of a wireless charging area according to claim 3, characterized by, The step S26 specifically includes the following steps: The thermal imaging picture and the real object picture at the previous moment and the current moment are input into the trained foreign matter classification model, the foreign matter classification model outputs the corresponding foreign matter category, and marks the positions of each type of foreign matter on the real object picture at the current moment. 5.The foreign matter recognition method of a wireless charging area according to claim 4, characterized in that: The foreign matter classification model can classify foreign matters into three categories, namely metal foreign matter, biological foreign matter and other foreign matter; during the training of the foreign matter classification model, the data set samples used are the thermal imaging pictures and the real object pictures generated in the same environment, and the positions and categories of the foreign matters are marked.

6. A foreign object recognition system for a wireless charging area, characterized by The device comprises one or more ultrasonic sensors (11), two or more light sensors (12), a telescopic imaging module (13), and a control module (14) connected to the ultrasonic sensor (11), the light sensor (12) and the imaging module (13); the ultrasonic sensor (11) is installed on the wireless charging parking space and is aligned with the wireless charging area; the light sensor (12) is installed on the four sides of the wireless charging area; the imaging module (13) is installed at the center of the wireless charging area of the wireless charging parking space below the ground, when the imaging module (13) works, the imaging module (13) extends out of the ground by a predetermined height, when the imaging module (13) completes the work, the imaging module (13) is retracted below the ground; the imaging module (13) comprises an infrared thermal imager and a camera; The control module (14) is used for foreign matter detection and identification of the wireless charging area of the wireless charging parking space by using the ultrasonic sensor (11), the light sensor (12) and the imaging module (13), and the specific process of foreign matter detection and identification is as described in the step S2 of the foreign matter identification method of the wireless charging area of any one of claims 1~5.

Images