Wireless energy transmission power reduction operation method and system based on temperature rise protection

Abstract

The present application relates to the technical field of wireless power transmission, and specifically discloses a wireless power transmission power reduction operation method and system based on temperature rise protection, which first detects and identifies foreign objects, then sets expected temperatures for various foreign objects according to the types of foreign objects at this time and the distances between various foreign objects, subsequently acquires actual maximum temperatures of various foreign objects, and compares the actual maximum temperatures with the corresponding expected temperatures, if all the actual maximum temperatures are less than the corresponding expected temperatures, it indicates that there is no safety hazard at this time, and power transmission does not need to be reduced, otherwise, it indicates that there is a safety hazard, and power transmission needs to be reduced to reduce the actual temperature of metal foreign objects, until there is no foreign object or the actual temperatures of various foreign objects are all less than the expected temperatures. The present application controls the wireless power transmission power according to the categories and temperatures of foreign objects, so that when foreign objects intervene in the wireless charging area, the power transmission can be kept as large as possible under the premise of ensuring safety.

Description

Technical Field

[0001] This invention relates to the field of wireless power transmission technology, and in particular to a wireless power transmission power reduction operation method and system based on temperature rise protection. 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 (MC-WPT) 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 cause heating 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, etc.) may burn living organisms. For other foreign objects such as plastics and paper scraps, especially plastics, high temperatures (near metallic foreign objects) can easily pose safety hazards (melting or even combustion).

[0004] In some unattended wireless charging scenarios, such as wireless charging of electric vehicles at night, if a metal object accidentally falls onto the charging pad on the transmitting side, existing foreign object detection solutions will automatically disconnect the energy transmission of the electric vehicle wireless charging to avoid any problems. However, this will cause a long interruption in the system's power transmission, so that the electric vehicle's battery will never receive power. Summary of the Invention

[0005] This invention provides a wireless power transfer power reduction operation method and system based on temperature rise protection. The technical problem it solves is: how to control the wireless power transfer power according to the type of foreign object and temperature, so that when a foreign object enters the wireless charging area, the power transfer can be maintained as much as possible while ensuring safety.

[0006] To address the above technical problems, this invention provides a wireless power transfer power reduction operation method based on temperature rise protection, comprising the following steps:

[0007] 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.

[0008] 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;

[0009] N3. Activate temperature detection to obtain the actual highest temperature value of various foreign objects;

[0010] 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.

[0011] 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.

[0012] Further, in step N2:

[0013] If the identified foreign object type contains only metallic foreign objects, the expected temperature of the metallic foreign objects is set to T1;

[0014] If the identified foreign object type contains only biological foreign objects, the expected temperature of the biological foreign objects is set to T2;

[0015] If the identified foreign object type contains only other foreign objects, the expected temperature of the other foreign objects is set to T3;

[0016] 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:

[0017] T4=α1(1-β1)T1

[0018] T5=(1-β1)T2

[0019] Where α1 represents the influence coefficient of the biological foreign body on T2, and β1 represents the shortest distance D between the metallic foreign body and the biological foreign body. min1 The influence coefficient of foreign bodies on organisms;

[0020] 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:

[0021] T6=α2(1-β2)T1

[0022] T7=(1-β2)T3

[0023] 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;

[0024] 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:

[0025] T8=α3(1-β3)(1-β4)T1

[0026] T9=(1-β3)T2

[0027] T 10 =(1-β4)T3

[0028] 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;

[0029] 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.

[0030] Furthermore, 0.8≤α1≤1, 0.6≤α2≤0.8, and α3=α2.

[0031] Furthermore, β1, β2, β3, and β4 are set as follows:

[0032]

[0033]

[0034]

[0035]

[0036] Furthermore, step N1 specifically includes the following steps:

[0037] 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.

[0038] 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.

[0039] Furthermore, step S2 specifically includes the following steps:

[0040] S21. Use an ultrasonic sensor to detect the wireless charging area to determine if there are any foreign objects in the wireless charging area. If so, proceed to step S22; otherwise, continue the detection.

[0041] 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.

[0042] S23. Use an ultrasonic sensor to detect the wireless charging area and determine whether the foreign objects in the wireless charging area are no longer there. If they are no longer there, return to step S21. If there are foreign objects in the area outside the center of the wireless charging area, proceed to step S24. If there are still foreign objects in the center of the wireless charging area, remove the foreign objects and return to step S21.

[0043] 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.

[0044] 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.

[0045] S26. Identify the type of foreign object based on the thermal imaging image and the physical object image.

[0046] 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:

[0047] Extend the imaging module out of the ground at a predetermined height;

[0048] 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.

[0049] 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.

[0050] The clean frames of each thermal image are fused to obtain a thermal image of the wireless charging area.

[0051] In step S25, the camera is used to take pictures of the wireless charging area to obtain physical images, specifically including the following steps:

[0052] 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.

[0053] 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.

[0054] The clean frames of each object are fused together to obtain a physical image of the wireless charging area.

[0055] Further, step S26 specifically includes:

[0056] 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 at the current moment.

[0057] 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.

[0058] Further, in step N2, based on the positions of various foreign objects marked by the foreign object classification model, the ultrasonic sensor is used to measure the distance between the various foreign objects;

[0059] In step N3, the infrared thermal imager is used for temperature detection.

[0060] The present invention also provides a wireless power transmission power reduction operation system based on temperature rise protection, the key features of which are: including a foreign object identification module, a desired temperature setting module, a temperature detection module, a temperature comparison module, and a power control module;

[0061] The foreign object identification module, the desired temperature setting module, the temperature detection module, the temperature comparison module, and the power control module are respectively used to execute steps N1 to N5 in the above method;

[0062] The foreign object detection module 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. When the imaging module is working, it extends above the ground to a preset height; when the imaging module is finished working, it retracts below the ground. The imaging module includes an infrared thermal imager and a camera.

[0063] 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.

[0064] The present invention provides a wireless power transfer reduction method and system based on temperature rise protection. First, foreign objects are detected and identified. Then, a desired temperature is set for each type of foreign object based on its type and distance from other objects. The highest actual temperature of each type of foreign object is then obtained and compared with its 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, a safety hazard exists, 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 the wireless power transfer based on the type and temperature of the foreign object, ensuring maximum power transfer while maintaining safety even when foreign objects are present in the wireless charging area. Attached Figure Description

[0065] Figure 1This is a flowchart of a wireless power transmission power reduction operation method based on temperature rise protection provided in an embodiment of the present invention;

[0066] Figure 2 This is a detailed flowchart of step N1 provided in an embodiment of the present invention;

[0067] Figure 3 This is a top view of a parking space provided in an embodiment of the present invention;

[0068] Figure 4 This is a structural diagram of a wireless power transmission system with reduced power output based on temperature rise protection, provided in an embodiment of the present invention.

[0069] Figure reference numerals: 11-ultrasonic sensor, 12-light sensor, 13-imaging module, 14-control module. Detailed Implementation

[0070] 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.

[0071] The wireless power transfer power reduction operation method based on temperature rise protection provided in this embodiment of the invention, such as... Figure 1 The flowchart shown includes the following steps:

[0072] 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. Foreign object category identification classifies foreign objects into 3 categories: metallic foreign objects, biological foreign objects, and other foreign objects other than metallic foreign objects and biological foreign objects.

[0073] 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;

[0074] N3. Activate temperature detection to obtain the actual highest temperature value of various foreign objects;

[0075] 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.

[0076] 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.

[0077] Specifically, such as Figure 2As shown in the flowchart, step N1 specifically includes the following steps:

[0078] S1, such as Figure 3 As shown in the top view of the parking space, one or more ultrasonic sensors 11 aligned with the wireless charging area are installed on the wireless charging parking space; two or more light sensors 12 are installed on the four sides of the wireless charging area of ​​the wireless charging parking space; a retractable and rotatable 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, the imaging module 13 extends out of the ground to a preset height, and 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.

[0079] S2. An ultrasonic sensor 11, a light sensor 12, and an imaging module 13 are used to detect and identify foreign objects in the wireless charging area of ​​the wireless charging parking space.

[0080] Step S2 specifically includes the following steps:

[0081] S21. Use ultrasonic sensor 11 to detect the wireless charging area to determine whether there are foreign objects in the wireless charging area. If so, proceed to step S22; otherwise, continue the detection.

[0082] 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.

[0083] S23. Use ultrasonic sensor 11 to detect the wireless charging area and determine whether the foreign objects in the wireless charging area are no longer there. If they are no longer there, return to step S21. If there are foreign objects in the area outside the center of the wireless charging area, proceed to step S24. If there are still foreign objects in the center of the wireless charging area, remove the foreign objects and return to step S21.

[0084] 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.

[0085] S25. An infrared thermal imager is used to take pictures of the wireless charging area to obtain thermal images, and a camera is used to take pictures of the wireless charging area to obtain physical images.

[0086] S26. Identify the type of foreign object based on thermal imaging images and physical object images.

[0087] 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.

[0088] 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.

[0089] 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).

[0090] 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.

[0091] 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.

[0092] Specifically, in step S25, an infrared thermal imager is used to take pictures of the wireless charging area to obtain thermal images, which includes the following steps:

[0093] Extend the imaging module 13 out of the ground at a preset height;

[0094] The rotating imaging module 13 rotates once, and the infrared thermal imager captures the wireless charging area from different angles to obtain the original thermal image frame.

[0095] 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.

[0096] The clean frames from each thermal imaging image are fused to obtain a thermal image of the wireless charging area.

[0097] 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.

[0098] Specifically, in step S25, a camera is used to take a picture of the wireless charging area to obtain a physical image, which includes the following steps:

[0099] During the process of rotating the imaging module 13, the camera captures the wireless charging area from different angles to obtain the original frame of the object.

[0100] 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.

[0101] The clean frames of each object are fused together to obtain a physical image of the wireless charging area.

[0102] 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.

[0103] 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.

[0104] Step S26 is as follows:

[0105] The thermal imaging images from the previous moment and the current moment, along with the images of the actual objects, are input into the trained foreign object classification model. The model outputs the corresponding foreign object types and marks the locations of each type of foreign object on the current image of the actual objects.

[0106] 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 thermal imaging images and real object images generated in the same environment, in which the location and type of foreign objects are labeled.

[0107] 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.

[0108] It should also be noted that, such as Figure 3 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.

[0109] This embodiment 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 achieves high accuracy in foreign object recognition, precisely distinguishing whether foreign objects interfering with the wireless charging area are metallic, biological, or other types, and marking the location of each object. Garage managers can then target and remove foreign objects based on their type and location. This foreign object identification feature can be integrated with other aspects of the wireless charging system design to achieve higher-quality control.

[0110] In step N2:

[0111] If the identified foreign object type contains only metallic foreign objects, the expected temperature of the metallic foreign objects is set to T1;

[0112] If the identified foreign object type contains only biological foreign objects, the expected temperature of the biological foreign objects is set to T2;

[0113] If the identified foreign object type contains only other foreign objects, the expected temperature of the other foreign objects is set to T3;

[0114] 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:

[0115] T4=α1(1-β1)T1

[0116] T5=(1-β1)T2

[0117] Where α1 represents the influence coefficient of the biological foreign body on T2, and β1 represents the shortest distance D between the metallic foreign body and the biological foreign body. min1 The influence coefficient of foreign bodies on organisms;

[0118] 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:

[0119] T6=α2(1-β2)T1

[0120] T7=(1-β2)T3

[0121] 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;

[0122] 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:

[0123] T8=α3(1-β3)(1-β4)T1

[0124] T9=(1-β3)T2

[0125] T 10 =(1-β4)T3

[0126] 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;

[0127] 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.

[0128] 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.

[0129] In general, 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:

[0130]

[0131]

[0132]

[0133]

[0134] In step N2, based on the positions of various foreign objects marked by the foreign object classification model, the ultrasonic sensor 11 is used to measure the distance between the various foreign objects;

[0135] In step N3, an infrared thermal imager is used for temperature detection.

[0136] In step N5, this example uses a PID control process for power regulation. The specific process is as follows:

[0137] Calculate the difference between the temperature of all types of foreign objects and their expected temperature, and find the maximum temperature difference;

[0138] The corresponding control signal is calculated based on the maximum temperature difference and applied to the AC-DC converter using a PID control algorithm.

[0139] 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.

[0140] In summary, the wireless power transfer reduction method based on temperature rise protection provided in this invention first detects and identifies foreign objects. Then, based on the type of foreign object and the distance between them, it sets a desired temperature for each type of foreign object. 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, it indicates no safety hazard and no power reduction is needed; otherwise, it indicates a safety hazard and power reduction is required 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 the wireless power transfer based on the type and temperature of the foreign object, ensuring a relatively high power transfer while maintaining safety even when a foreign object is present in the wireless charging area.

[0141] Example 2

[0142] like Figure 4 As shown, this embodiment provides a wireless power transmission power reduction operation system based on temperature rise protection, including a foreign object identification module, a desired temperature setting module, a temperature detection module, a temperature comparison module, and a power control module;

[0143] The foreign object identification module, the desired temperature setting module, the temperature detection module, the temperature comparison module, and the power control module are respectively used to execute steps N1 to N5 of Embodiment 1.

[0144] The specific foreign object detection module 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, light sensors 12, and 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 in 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.

[0145] The control module 14 is used to detect and identify foreign objects in the wireless charging area of ​​the wireless charging parking space using an ultrasonic sensor 11, a light sensor 12, and an imaging module 13.

[0146] The control module 14 uses an ultrasonic sensor 11, a light sensor 12, and an imaging module 13 to perform foreign object detection and identification in the wireless charging area of ​​the wireless charging parking space. The specific process is as described in step S2 of Example 1.

[0147] The control module 14, the desired temperature setting module, the temperature detection module, the temperature comparison module, and the power control module here can directly use the MCU of the primary side transmitter.

[0148] Other details have been described in Implementation Example 1, and will not be repeated here.

[0149] 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 wireless power transmission power reduction operation method based on temperature rise protection, characterized in that, Including the following steps: 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. 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; N3. Activate temperature detection to obtain the actual highest temperature value of various foreign objects; 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. 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. In step N2: If the identified foreign object type contains only metallic foreign objects, the desired temperature for the metallic foreign objects is set to... ; If the identified foreign object types only include biological foreign objects, the desired temperature for biological foreign objects is set to... ; If the identified foreign object type contains only other foreign objects, the expected temperature of the other foreign objects is set to... ; If the identified foreign object types include both metallic and biological foreign objects, the desired temperature for metallic foreign objects is set to... The desired temperature for foreign objects in living organisms is set to , , satisfy: ， ， in, Indicates the effect of foreign bodies on organisms Influence coefficient, Indicates the shortest distance between a metallic foreign object and a biological foreign object. The influence coefficient of foreign bodies on organisms; If the identified foreign object type contains both metallic and other foreign objects, the desired temperature for the metallic foreign object is set to... The desired temperature for other foreign objects is set to , , satisfy: ， ， in, Indicates other foreign objects Influence coefficient, Indicates the shortest distance between a metallic foreign object and other foreign objects. Influence coefficient on other foreign objects; If the identified foreign object types include metallic foreign objects, biological foreign objects, and other foreign objects, the desired temperature for metallic foreign objects is set to... The desired temperature for foreign objects in living organisms is set to The desired temperature for other foreign objects is set to , , , satisfy: ， ， ， in, This indicates the effect of three types of foreign bodies on the organism and other foreign bodies when they coexist. Influence coefficient, This represents the shortest distance between a metallic foreign object and a biological foreign object when all three are present. The influence coefficient of foreign bodies on organisms This indicates the shortest distance between a metallic foreign object and other foreign objects when all three are present. Influence coefficient on other foreign objects; If the identified foreign object types include both biological foreign objects and other foreign objects, the desired temperature for the biological foreign objects is set to... The desired temperature for other foreign objects is set to .

2. The wireless power transfer reduction operation method based on temperature rise protection according to claim 1, characterized in that: ， 。 3. The wireless power transfer power reduction operation method based on temperature rise protection according to claim 1, characterized in that, , , , Set to: ， ， ， 。 4. The wireless power transfer power reduction operation method based on temperature rise protection according to claim 3, characterized in that, Step N1 specifically includes the following steps: 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) finishes working, the imaging module (13) retracts under the ground. The imaging module (13) includes an infrared thermal imager and a camera. 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.

5. The wireless power transfer power reduction operation method based on temperature rise protection according to claim 4, characterized in that, Step S2 specifically includes the following steps: S21. Use an ultrasonic sensor (11) 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. 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. S23. Use an ultrasonic sensor (11) to detect the wireless charging area and determine whether the foreign objects on the wireless charging area are no longer there. If they are no longer there, return to step S21. If there are foreign objects in the area outside the center of the wireless charging area, proceed to step S24. If there are still foreign objects in the center of the wireless charging area, remove the foreign objects and return to step S21. 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. 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. S26. Identify the type of foreign object based on the thermal imaging image and the physical object image.

6. The wireless power transfer reduced-power operation method based on temperature rise protection according to claim 5, characterized in that, 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: Extend the imaging module (13) out of the ground at a predetermined height; Rotate the imaging module (13) one revolution, and the infrared thermal imager will capture the wireless charging area at different angles to obtain the original thermal image frame; 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. The clean frames of each thermal image are fused to obtain a thermal image of the wireless charging area. In step S25, the camera is used to take pictures of the wireless charging area to obtain physical images, specifically including the following steps: During the rotation of the imaging module (13), the camera captures the wireless charging area at different angles to obtain the original frame of the object; 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. The clean frames of each object are fused together to obtain a physical image of the wireless charging area.

7. The wireless power transfer reduced-power operation method based on temperature rise protection according to claim 6, characterized in that, Step S26 specifically involves: 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 at the current moment. 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.

8. The wireless power transfer reduced-power operation method based on temperature rise protection according to claim 7, characterized in that: In step N2, the distance between various foreign objects is measured using the ultrasonic sensor (11) based on the positions of the foreign objects marked by the foreign object classification model. In step N3, the infrared thermal imager is used for temperature detection.

9. A wireless power transmission system with reduced power output based on temperature rise protection, characterized in that: It includes a foreign object detection module, a desired temperature setting module, a temperature detection module, a temperature comparison module, and a power control module; The foreign object identification module, the desired temperature setting module, the temperature detection module, the temperature comparison module, and the power control module are respectively used to perform steps N1 to N5 as described in any one of claims 1 to 8; The foreign object identification module 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 on 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, and when it finishes working, it retracts back under the ground; the imaging module (13) includes an infrared thermal imager and a camera; The control module (14) is used to perform foreign object detection and foreign object 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).

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