Foreign object detection device and method for wireless charging system
Through the quadrilateral optical path design and infrared beam scanning system, the high false alarm rate and high hardware overhead problems of non-metallic foreign object detection in wireless charging systems are solved, achieving high-precision and low-cost foreign object detection, improving user experience and avoiding electromagnetic field interference.
Patent Information
- Application Number
- CN202211137954.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-09-19
- Publication Date
- 2025-09-30
- Estimated Expiration
- 2042-09-19
AI Technical Summary
In existing wireless charging systems, non-metallic foreign object detection methods have problems such as high false alarm rate, large hardware overhead, unadjustable detection accuracy, and susceptibility to electromagnetic fields.
It adopts a quadrilateral optical path design and uses a scanning system composed of infrared beams and reflective surfaces. It converts the optical path shielding into binary code to detect the outline of foreign objects. It combines carbon dioxide sensors, temperature and humidity sensors, and light sensors to achieve foreign object detection.
It achieves high-precision detection of various foreign objects, reduces system costs, improves user experience, avoids the influence of electromagnetic field coupling, and detection does not require the cooperation of user equipment.
Smart Images
Figure CN115459466B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of wireless charging, and in particular to a foreign object detection device and method for a wireless charging system. Background Art
[0002] Wireless charging technology is gradually being promoted in the field of electric vehicle charging, and charging safety solutions are an important part of wireless charging solutions for electric vehicles, among which foreign object detection technology is a necessary guarantee for charging safety. Foreign object detection technology can be divided into metal foreign object detection and non-metal foreign object detection. Metal foreign object detection is mainly based on the changes in the electrical parameters of the wireless charging system caused by metal, such as transmission efficiency, output power, input impedance, and the quality factor of the induction coil; while non-metallic foreign objects are mainly judged through imaging, ultrasonic and other methods. The methods for detecting non-metallic foreign objects can basically be used for metal detection, while the methods for detecting metal foreign objects cannot be used for non-metal detection. Therefore, the detection methods for non-metallic foreign objects are extensive and universal. In the following text, non-metallic foreign object detection will be referred to as universal foreign object detection.
[0003] There are currently three main technologies for general foreign body detection: (1) Methods based on ultrasonic measurement, such as patent CN210744832U, which proposes using ultrasonic sensors to detect the distance value of the car chassis. If the value fluctuates greatly, there is a foreign body. This method cannot determine the size of the foreign body and may cause false alarms; (2) Methods based on image recognition, such as patent CN210062694U, which proposes a foreign body detection device for wireless charging of electric vehicles based on image recognition. The device collects images through a high-definition camera and then uses an image algorithm to identify and detect foreign bodies. This method has the problem that camera dirt affects recognition and the hardware overhead of the image algorithm is high; (3) Foreign body detection based on optical principles, such as patent CN108855999A, which uses an L-shaped light-emitting strip and a set of axially symmetrical receiving strips to form an optical path grid to detect foreign bodies. This method cannot arbitrarily adjust the detection accuracy and will be falsely reported as a foreign body when a single light source or receiver fails.
[0004] To this end, a foreign object detection device and method for a wireless charging system are proposed. Summary of the Invention
[0005] The present invention aims to provide a foreign object detection device and method for a wireless charging system to address the problems raised in the aforementioned background art. To achieve this objective, the present invention provides the following technical solution: a foreign object detection device and method for a wireless charging system, comprising a quadrilateral ABCD, characterized in that quadrilateral ABCD is a square with the following geometric dimensions: arc IJ is a quarter-circle arc with center C and radius CI; arc EF is a quarter-circle arc with center C and radius CE; EF and IJ are concentric. Arc KL is a quarter-circle arc with center A and radius AL; arc HG is a quarter-circle arc with center A and radius AH; KL and GH are concentric. Point M is the intersection of an extended line CA and arc EF, and point N is the intersection of an extended line AC and arc GH.
[0006] Preferably, the working area of the wireless charging system is within the square ABCD, and the square ABCD is the foreign object detection range of the device.
[0007] A foreign object detection device and method for a wireless charging system, characterized by comprising the following steps:
[0008] S1: Infrared beam emitting devices are respectively set at points A and C of this device. Point A emits beam 1, with an angle α with line AB; point C emits beam 2, with an angle β with line CB. Photodiodes are respectively set at points M and N. Two arc-shaped reflective surfaces are set, with the lower edge of one reflective surface along the KL arc and the upper edge along the GH arc. That is, this reflective surface is arranged at an angle. When there is no obstruction, this reflective surface can reflect the infrared beam emitted from point A to the reflective surface back to point M to be received by the photodiode, such as Figure 2 As shown; similarly, the lower edge of the other reflective surface is along the IJ arc, and the upper edge is along the EF arc. This reflective surface is also arranged at an angle. When there is no obstruction, this reflective surface can reflect the infrared beam emitted from point C to the reflective surface back to point N to be received by the photosensitive diode;
[0009] S2: Through analog and digital circuits, the photodiode receives light and conducts, setting the binary value to "1." The photodiode does not receive light and is not conducting, setting the binary value to "0." That is, when there are no obstacles in the light path, the digital value is "1." When there are obstacles in the path, the digital value is "0."
[0010] S3: Uniformly grid the foreign object detection area ABCD into p points. These p points constitute the point set P, where the value of p can be adjusted according to the required accuracy. Each point in the grid can be represented by a unique (α, β) coordinate, where α, β∈[0, 90]. At the same time, light beams 1 and 2 can traverse every angle that satisfies α, β∈[0, 90] by rotating through the transmitting device. The angle increment is determined by the value of p. In summary, the scanning system composed of light beams 1 and 2 can traverse every point in the point set P;
[0011] S4: Arranging the binary values corresponding to the (α, β) coordinates obtained by scanning to form the outer contour of the foreign body.
[0012] The model of the carbon dioxide sensor is MG-812, the model of the temperature and humidity sensor is SHT11, and the model of the light sensor is GY-302.
[0013] Compared with the prior art, the present invention has the following beneficial effects:
[0014] 1. This solution can realize the detection of various types of foreign objects in wireless charging systems;
[0015] 2. This solution can measure the size of foreign matter;
[0016] 3. This solution is simple and highly reliable, effectively reducing the cost of the foreign object detection system. It also does not require user equipment matching, improving the user experience.
[0017] 4. The technology adopted in this solution uses optical path as the detection medium, avoiding coupling with the system electromagnetic field. The operation of the detection system has no impact on the main circuit of the wireless charging system. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.
[0019] Figure 1 The geometric diagram of the experimental device of the present invention;
[0020] Figure 2 This is the light reflection path of the present invention;
[0021] Figure 3 Foreign object detection coding results. DETAILED DESCRIPTION
[0022] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.
[0023] See also Figures 1 to 2The present invention provides a technical solution: a foreign object detection device and method for a wireless charging system, comprising a quadrilateral ABCD. The quadrilateral ABCD is a square with the following geometric dimensions: arc IJ is a quarter-circle arc with center C and radius CI; arc EF is a quarter-circle arc with center C and radius CE; EF and IJ are concentric. Arc KL is a quarter-circle arc with center A and radius AL; arc HG is a quarter-circle arc with center A and radius AH; KL and GH are concentric. Point M is the intersection of the extended line CA and arc EF; and point N is the intersection of the extended line AC and arc GH.
[0024] Preferably, the working area of the wireless charging system is within the square ABCD, and the square ABCD is the foreign object detection range of the device.
[0025] A foreign object detection device and method for a wireless charging system, characterized by comprising the following steps:
[0026] S1: Infrared beam emitting devices are respectively set at points A and C of this device. Point A emits beam 1, with an angle α with line AB; point C emits beam 2, with an angle β with line CB. Photodiodes are respectively set at points M and N. Two arc-shaped reflective surfaces are set, with the lower edge of one reflective surface along the KL arc and the upper edge along the GH arc. That is, this reflective surface is arranged at an angle. When there is no obstruction, this reflective surface can reflect the infrared beam emitted from point A to the reflective surface back to point M to be received by the photodiode, such as Figure 2 As shown; similarly, the lower edge of the other reflective surface is along the IJ arc, and the upper edge is along the EF arc. This reflective surface is also arranged at an angle. When there is no obstruction, this reflective surface can reflect the infrared beam emitted from point C to the reflective surface back to point N to be received by the photosensitive diode;
[0027] S2: Through analog and digital circuits, the photodiode receives light and conducts, setting the binary value to "1." The photodiode does not receive light and is not conducting, setting the binary value to "0." That is, when there are no obstacles in the light path, the digital value is "1." When there are obstacles in the path, the digital value is "0."
[0028] S3: Uniformly grid the foreign object detection area ABCD into p points. These p points constitute the point set P, where the value of p can be adjusted according to the required accuracy. Each point in the grid can be represented by a unique (α, β) coordinate, where α, β∈[0, 90]. At the same time, light beams 1 and 2 can traverse every angle that satisfies α, β∈[0, 90] by rotating through the transmitting device. The angle increment is determined by the value of p. In summary, the scanning system composed of light beams 1 and 2 can traverse every point in the point set P;
[0029] S4: Arranging the binary values corresponding to the (α, β) coordinates obtained by scanning to form the outer contour of the foreign body.
[0030] The model of the carbon dioxide sensor is MG-812, the model of the temperature and humidity sensor is SHT11, and the model of the light sensor is GY-302.
[0031] Through the above technical solution, the present invention detects foreign objects based on the principle of light path blocking. Specifically, it adopts a detection device design with two light paths and two reflecting surfaces. The light path obstruction is converted into binary code and then encoded into foreign object contour information. It can detect various foreign objects including metal and non-metal, determine the size of foreign objects, conveniently adjust the detection accuracy, and self-check sensor failures. Moreover, the device is installed on the transmitting side and does not require the cooperation of the receiving side. Therefore, detection can be performed when the user's vehicle is not using the charging system, thereby improving the user's charging efficiency.
[0032] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. A foreign object detection device for a wireless charging system, comprising a quadrilateral ABCD, characterized in that: The quadrilateral ABCD is a square, and its geometric dimensions are: arc IJ is a 1 / 4 arc with center C and radius CI, arc EF is a 1 / 4 arc with center C and radius CE, EF and IJ are concentric, arc KL is a 1 / 4 arc with center A and radius AL, arc HG is a 1 / 4 arc with center A and radius AH, KL and GH are concentric, point M is the intersection of the extended line CA and arc EF, and point N is the intersection of the extended line AC and arc GH; Infrared beam emitting devices are respectively set at points A and C of this device. Point A emits a light beam 1, which is at an angle α to the AB line; point C emits a light beam 2, which is at an angle β to the CB line. Photosensitive diodes are respectively set at points M and N. Two arc-shaped reflecting surfaces are set. The lower edge of one reflecting surface is along the KL arc, and the upper edge is along the GH arc. That is, this reflecting surface is arranged obliquely. When there is no obstruction, this reflecting surface can reflect the infrared beam emitted from point A to the reflecting surface back to point M to be received by the photosensitive diode. The lower edge of the other reflecting surface is along the IJ arc, and the upper edge is along the EF arc. This reflecting surface is also arranged obliquely. When there is no obstruction, this reflecting surface can reflect the infrared beam emitted from point C to the reflecting surface back to point N to be received by the photosensitive diode.
2. The foreign object detection device for a wireless charging system according to claim 1, characterized in that: The working area of the wireless charging system is within the square ABCD, which is the foreign object detection range of the device.
3. A foreign object detection device for a wireless charging system according to any one of claims 1 to 2, characterized in that: The following steps are involved: S1: Through analog and digital circuits, the state of the photodiode receiving light and conducting is set to the binary value "1", and the state of the photodiode not receiving light and not conducting is set to the binary value "0". That is, when there is no obstacle in the light path, the digital value "1" is obtained; when there is an obstacle in the path, the digital value "0" is obtained; S2: The foreign object detection area ABCD is uniformly gridded into p points. These p points constitute the point set P, where the value of p can be adjusted according to the accuracy requirements. Each point in the grid can be represented by a unique (α, β) coordinate, where α, β∈[0, 90]. At the same time, light beams 1 and 2 can traverse every angle that satisfies α, β∈[0, 90] by rotating through the transmitting device. The angle increment is determined by the value of p. In summary, the scanning system composed of light beams 1 and 2 can traverse every point in the point set P; S3: Arranging the binary values corresponding to the (α, β) coordinates obtained by scanning to form the outer contour of the foreign body; The model of the carbon dioxide sensor is MG-812, the model of the temperature and humidity sensor is SHT11, and the model of the light sensor is GY-302.