Automatic automobile charging system and method based on strong coupling wireless charging technology

Abstract

The invention discloses an automobile automatic charging system and method based on a strong coupling wireless charging technology, and relates to the technical field of automobile wireless charging. A receiving coil is searched through a visual guidance camera, and the position of the receiving coil is obtained; the position is transmitted to the controller, the multi-dimensional moving platform is driven to adjust the position of the transmitting coil, so that the transmitting coil is aligned with the receiving coil and gradually and tightly attached to the receiving coil, and the distance between the transmitting coil and the receiving coil is reduced to the maximum extent; and finally, the coupling coefficient between the receiving coil and the transmitting coil is optimized, and the coupling coefficient can be basically constant even if small-range offset exists between the receiving coil and the transmitting coil. When the receiving coil and the transmitting coil deviate within a large range, full-automatic alignment of the receiving coil and the transmitting coil can be achieved, the coupling coefficient is basically unchanged, meanwhile, metal foreign matter on the transmitting coil can be effectively removed, and an effective method is provided for full-automatic efficient charging of the electric vehicle.

Description

Technical Field

[0001] The present invention relates to the technical field of wireless charging of electric vehicles, and in particular to an automatic charging system and method for an automobile based on strong coupling wireless charging technology. Background Art

[0002] The charging system is one of the core components of electric vehicles, and its performance directly affects the safety and convenience of electric vehicles. Currently, there are two main ways to charge electric vehicles: plug-in wired charging and wireless charging.

[0003] The main problems of plug-in wired charging are as follows:

[0004] (1) The flexibility of electric vehicle charging is greatly reduced due to the existence of charging sockets and cables;

[0005] (2) Large charging currents pose a potential risk of leakage and electric shock, and are prone to generating contact sparks, making them unsafe.

[0006] Wireless charging mainly transmits electrical energy through magnetic fields. The power supply end and the load end do not need to be directly connected by wires, thus eliminating the need for sockets and plugs. The load end and the power supply end can be intelligently connected through network instructions, making it easier to achieve intelligent power supply. However, during dynamic wireless charging of electric vehicles, the transmitting coil and the receiving coil will inevitably be offset, causing the coupling coefficient between the coils to change, which in turn causes the output voltage to fluctuate violently and the efficiency to decrease, endangering the safety and stability of the dynamic wireless power supply system of electric vehicles.

[0007] Therefore, how to ensure that the coupling coefficient between the coils remains as constant as possible and, on this basis, to improve the transmission efficiency as much as possible to achieve stable and efficient wireless power transmission is a difficult problem. Summary of the invention

[0008] In view of the above problems, the present invention provides an automatic automobile charging system and method based on strong coupling wireless charging technology. When the receiving coil and the transmitting coil of the electric vehicle wireless charging system are offset within a large range, the present invention can realize the fully automatic alignment of the receiving coil and the transmitting coil with the coupling coefficient basically unchanged, and at the same time, the metal foreign matter on the transmitting coil can be removed, thereby providing an effective method for fully automatic and efficient charging of electric vehicles.

[0009] To achieve the above purpose, the technical solution adopted by the present invention is:

[0010] An automatic automobile charging system based on strong coupling wireless charging technology includes a grid-side rectifier, an inverter, a transmitting coil, a receiving coil, a multi-dimensional mobile platform, and a vision-guided camera. The position of the receiving coil is obtained by the vision-guided camera, and the movement of the multi-dimensional mobile platform is controlled by a controller. In conjunction with an optimization algorithm for the coupling coefficient between the transmitting coil and the receiving coil, the transmitting coil and the receiving coil of the wireless charging system are accurately aligned and tightly fitted. Even if the receiving coil and the transmitting coil are offset, the coupling coefficient between the receiving coil and the transmitting coil can be kept basically unchanged, thereby completing automatic charging.

[0011] This system uses a grid-side rectifier, inverter, transmitting coil and receiving coil, combined with a multi-dimensional mobile platform and a vision-guided camera to achieve precise alignment and close fit between the transmitting coil and the receiving coil. The vision-guided camera obtains the position information of the receiving coil, and the controller drives the multi-dimensional mobile platform based on this information to adjust the position of the transmitting coil to achieve alignment. At the same time, with the coupling coefficient optimization algorithm, even when the receiving coil and the transmitting coil are offset, the coupling coefficient can be kept basically unchanged to complete automatic charging.

[0012] This system can achieve fully automatic alignment and keep the coupling coefficient basically unchanged when the receiving coil and transmitting coil of the electric vehicle wireless charging system are offset over a large range, thus improving the stability and efficiency of wireless charging. At the same time, the system can also remove metal foreign matter on the transmitting coil, providing a fully automatic, efficient and safe charging method for electric vehicles.

[0013] As a further improvement of the above solution, the multi-dimensional mobile platform realizes the three-coordinate movement and angle adjustment of the transmitting coil. This can adapt to the receiving coils at different positions and angles, ensuring the precise alignment of the transmitting coil and the receiving coil. Through the three-coordinate movement and angle adjustment, the system can more flexibly adapt to different charging environments and vehicle positions, improving the adaptability and accuracy of charging.

[0014] As a further improvement of the above solution, the multi-dimensional mobile platform is used to control the flipping of the transmitting coil, so that the foreign objects on the transmitting coil can slide off, thereby achieving the purpose of removing the foreign objects. The system controls the flipping of the transmitting coil through a multi-dimensional mobile platform, so that the foreign objects on the transmitting coil can slide off, thereby achieving the purpose of removing the foreign objects. Removing metal foreign objects from the transmitting coil can avoid safety hazards during the charging process and ensure the safety and efficiency of the charging process.

[0015] As a further improvement of the above solution, the visual guidance camera and the transmitting coil are installed on the multi-dimensional mobile platform, so that the visual guidance camera can obtain the position information of the receiving coil in real time and guide the multi-dimensional mobile platform to adjust the position of the transmitting coil.

[0016] As a further improvement of the above scheme, the coupling coefficient optimization algorithm includes the following steps:

[0017] S1, establish a transmitting coil to receiving coil model: it consists of a transmitting coil and a receiving coil whose size is larger than the transmitting coil, and the receiving coil is parallel to the transmitting coil;

[0018] S2, set the main parameters: including the diameter of the copper wire, the resonant frequency, and the distance between the transmitting coil and the receiving coil;

[0019] S3, setting specification constraints: setting constraints according to actual application and design requirements; including the range of inner length of the transmitting coil, the range of inner width of the transmitting coil, the range of the number of turns of the transmitting coil, the range of inner length of the receiving coil, the range of inner width of the receiving coil, the range of the number of turns of the receiving coil, and the step size;

[0020] S4, calculating the mutual inductance and self-inductance of the transmitting coil and the receiving coil;

[0021] S5, set the coupling coefficient k and the coupling coefficient fluctuation rate requirements: set the coupling coefficient k ≥ 0.12; when the lateral offset is 3 cm, the coupling coefficient fluctuation rate is ≤ 5%; when the longitudinal offset is 3 cm, the coupling coefficient fluctuation rate is ≤ 5%;

[0022] S6, calculate the coupling coefficient and the coupling coefficient fluctuation rate;

[0023] S7, judging whether the coupling coefficient and the coupling coefficient fluctuation rate meet the requirements: comparing the current coupling coefficient and the coupling coefficient fluctuation rate with the set values, if they meet the requirements, saving the parameters that meet the conditions; if they do not meet the requirements, further adjusting the device parameters;

[0024] S8, repeat the above steps S3 to S7 until all parameters reach the upper limit.

[0025] The coupling coefficient optimization algorithm includes building a model, setting parameters, calculating mutual inductance and self-inductance, setting coupling coefficient requirements, calculating coupling coefficient and fluctuation rate, judging whether the requirements are met, and adjusting device parameters as needed until all parameters reach the upper limit. By accurately calculating and optimizing the coupling coefficient, the system can maintain a high coupling coefficient and a low fluctuation rate when the transmitting coil and the receiving coil are offset, thereby improving charging efficiency and stability.

[0026] As a further improvement of the above solution, in S4, the self-inductance of the transmitting coil and the receiving coil is calculated according to the self-inductance calculation formula of the rectangular coil;

[0027] The formula is:

[0028]

[0029] Among them: B 4zis the magnetic flux density, D is T x and R x Transmission distance between 0 is the vacuum permeability, a 1 and a 2 are the length and width of the transmitting coil, ξ and η are the double Fourier transform parameters, I is the excitation current added to the transmitting coil, and t represents time.

[0030] By calculating the self-inductance of the transmitting and receiving coils according to the rectangular coil self-inductance calculation formula, the electromagnetic characteristics of the coils can be determined more accurately, which is crucial for optimizing the energy transfer efficiency during wireless charging. Accurate calculation of self-inductance helps to design a more efficient wireless charging system because it directly affects the system's energy coupling and power transfer capabilities.

[0031] As a further improvement of the above scheme, the mutual inductance between the single-turn rectangular coils is calculated according to the mutual inductance formula between the single-turn rectangular coils under different coil offsets;

[0032] The formula is:

[0033]

[0034] Where: B is the magnetic flux density, I is the excitation current added to the transmitting coil, b 1d and b 2d is the offset distance along the X-axis and Y-axis, b 1 and b 2 It's Coil 2 The length and width of ξ and η are the double Fourier transform parameters, S 2 is the vertical distance between the receiving coil and the ground, C iz and C ix is an intermediate variable, and its specific expressions are shown in formulas (3) and (4):

[0035] Formula (3) is:

[0036]

[0037] Formula (4) is:

[0038]

[0039] Where: j: imaginary unit, representing the square root of -1, μ 0 is the magnetic permeability in vacuum, I is the excitation current added to the transmitting coil, Z 0 is the vertical distance between the transmitting coil and the ground, It is an exponential term, which represents the propagation attenuation of electromagnetic waves in space.

[0040] Under different coil offset conditions, the mutual inductance between single-turn rectangular coils is calculated according to the mutual inductance formula between single-turn rectangular coils, so that the system can adapt to the different relative positions between the coils, thereby maintaining high charging efficiency under various offset conditions. This calculation method helps to optimize the coil design and ensure that the charging system can maintain effective energy transfer even in non-ideal alignment conditions.

[0041] As a further improvement of the above scheme, the total mutual inductance value is calculated according to the mutual inductance calculation formula between the multi-turn coils;

[0042] The formula is:

[0043] Where: N 1 and N 2 are the number of turns of the transmitting coil and the receiving coil respectively, m is the mth turn of the transmitting coil, and n is the nth turn of the receiving coil.

[0044] Calculating the total mutual inductance value based on the mutual inductance calculation formula between multi-turn coils can more accurately predict and control the energy transfer between coils. This calculation method is critical to ensuring that the wireless charging system can achieve optimal performance under various operating conditions because it involves complex electromagnetic interactions between coils.

[0045] An automatic vehicle charging method based on strong coupling wireless charging technology, used in an automatic vehicle charging system, comprises the following steps:

[0046] S1, set the X, Y, Z axis coordinate error and angle rotation error requirements: set the error between the actual coordinate in the X direction and the set coordinate to be less than 3cm; set the error between the actual coordinate in the Y direction and the set coordinate to be less than 3cm; set the error between the actual coordinate in the Z direction and the set coordinate to be less than 0.1cm;

[0047] S2, after the electric vehicle arrives at the parking area, the visually guided camera searches for the position of the receiving coil on the electric vehicle to obtain the coordinate position and deflection angle of the receiving coil;

[0048] S3, the controller obtains the coordinate position of the receiving coil, drives the multi-dimensional mobile platform to move, and adjusts the position of the transmitting coil so that the transmitting coil is basically aligned with the receiving coil;

[0049] S4, control the transmitting coil to flip through the multi-dimensional mobile platform, so that the foreign matter on the surface slides off, so as to achieve the goal of removing the foreign matter on the transmitting coil, and then reset;

[0050] S5, then controlling the transmitting coil and the receiving coil to gradually fit closely together through the multi-dimensional mobile platform;

[0051] S6, repeat the above steps S2 to S5 until all coordinate position parameters reach the set target.

[0052] A method for automatic car charging based on strong coupling wireless charging technology is provided, which realizes efficient and stable wireless charging through precise coordinate and angle control, as well as automatic alignment and close fit of the transmitting coil and the receiving coil. This method not only improves the charging efficiency, but also ensures the safety of the charging process by removing foreign objects from the transmitting coil, and ensures the accuracy and reliability of the charging process by repeating the adjustment process until the set target is reached.

[0053] Beneficial effects of the present invention:

[0054] When the receiving coil and the transmitting coil of the electric vehicle wireless charging system are offset within a large range, the present invention can realize the full-automatic alignment of the receiving coil and the transmitting coil, and the coupling coefficient remains basically unchanged. Even if the full-automatic alignment device has an error, the coupling coefficient between the receiving coil and the transmitting coil can be kept basically unchanged due to the use of an asymmetric coil device and a coupling coefficient optimization method. At the same time, the transmitting coil is flipped, so that foreign objects can slide off, achieving the goal of clearing metal foreign objects on the transmitting coil, providing a safe and effective method for fully automatic and efficient charging of electric vehicles. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 This is the overall block diagram of the system.

[0056] Figure 2 Optimize the flow chart for the present invention.

[0057] In the figure: 1. X-axis motor; 2. Y-axis motor; 3. Z-axis motor; 4. Lifting mechanism; 5. First angle adjustment motor; 6. Second angle adjustment motor; 7. Vision-guided camera. DETAILED DESCRIPTION

[0058] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is described in detail below in conjunction with the accompanying drawings. The description in this part is only exemplary and explanatory and should not have any limiting effect on the protection scope of the present invention.

[0059] In order to make the above-mentioned purpose, features and advantages of the present invention more obvious and easy to understand, the specific implementation of the present invention is described in detail below. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific implementation disclosed below.

[0060] An automatic automobile charging system based on strong coupling wireless charging technology includes a grid-side rectifier, an inverter, a transmitting coil, a receiving coil, a multi-dimensional mobile platform, and a vision-guided camera. The position of the receiving coil is obtained by the vision-guided camera, and the movement of the multi-dimensional mobile platform is controlled by a controller. In conjunction with an optimization algorithm for the coupling coefficient between the transmitting coil and the receiving coil, the transmitting coil and the receiving coil of the wireless charging system are accurately aligned and tightly fitted. Even if the receiving coil and the transmitting coil are offset, the coupling coefficient between the receiving coil and the transmitting coil can be kept basically unchanged, thereby completing automatic charging.

[0061] As a preferred embodiment of the above embodiment, the multi-dimensional mobile platform realizes the three-coordinate movement and angle adjustment of the transmitting coil.

[0062] As a preferred embodiment of the above embodiment, the transmitting coil is controlled to flip by a multi-dimensional mobile platform so that foreign matter on the transmitting coil slides off, thereby achieving the purpose of removing the foreign matter.

[0063] As a preferred embodiment of the above embodiment, the vision-guided camera and the transmitting coil are installed on a multi-dimensional mobile platform.

[0064] Specifically, Figure 1 As shown, an automobile automatic charging system based on strong coupling wireless charging technology includes a power grid, a PWM rectifier, a high-frequency inverter, a transmitting side compensation network, and a transmitting coil;

[0065] An on-board device of an electric vehicle comprises: a receiving side compensation network, a receiving coil, a rectifier circuit, and a battery pack;

[0066] The multi-dimensional mobile platform is equipped with a transmitting coil and a vision-guided camera.

[0067] The structure of the multi-dimensional mobile platform is not limited to any form. Its main functions include realizing the three-coordinate movement of the transmitting coil and the adjustment of the angle. It can be in the form of a robotic arm, such as a three-coordinate robotic arm or a six-axis robotic arm, or it can be in the form of a platform structure.

[0068] like Figure 1 As shown, the multi-dimensional mobile platform can adopt a mobile platform; driven by a servo motor or a stepper motor, and realizes precise linear motion through a precision transmission mechanism (such as a ball screw, linear guide, etc.). The control system can be programmed as needed to realize automated movement and positioning tasks.

[0069] In this embodiment, the multi-dimensional mobile platform includes: an X-axis motor 1, a Y-axis motor 2, a Z-axis motor 3, a lifting mechanism 4, a first angle adjustment motor 5, and a second angle adjustment motor 6.

[0070] The X-axis motor 1 drives the lifting mechanism 4 to move horizontally, the Y-axis motor 2 drives the lifting mechanism 4 to move up and down, and the Z-axis motor 3 drives the lifting mechanism 4 to move vertically; the lifting mechanism 4 is not limited to a form, and can be a fork-type lifting frame structure; at the end of the lifting mechanism 4, the first angle adjustment motor 5 is used to realize the horizontal flipping of the transmitting coil, and the second angle adjustment motor 6 is used to realize the longitudinal flipping of the transmitting coil;

[0071] A transmitting coil and a visual guidance camera 7 are installed at the output end of the multi-dimensional mobile platform.

[0072] As a preferred embodiment of the above embodiment, the coupling coefficient optimization algorithm includes the following steps:

[0073] S1, establish a transmitting coil to receiving coil model: it consists of a transmitting coil and a receiving coil whose size is larger than the transmitting coil, and the receiving coil is parallel to the transmitting coil;

[0074] S2, set the main parameters: including the diameter of the copper wire, the resonant frequency, and the distance between the transmitting coil and the receiving coil;

[0075] S3, setting specification constraints: setting constraints according to actual application and design requirements; including the range of inner length of the transmitting coil, the range of inner width of the transmitting coil, the range of the number of turns of the transmitting coil, the range of inner length of the receiving coil, the range of inner width of the receiving coil, the range of the number of turns of the receiving coil, and the step size;

[0076] S4, calculating the mutual inductance and self-inductance of the transmitting coil and the receiving coil;

[0077] S5, set the coupling coefficient k and the coupling coefficient fluctuation rate requirements: set the coupling coefficient k ≥ 0.12; when the lateral offset is 3 cm, the coupling coefficient fluctuation rate is ≤ 5%; when the longitudinal offset is 3 cm, the coupling coefficient fluctuation rate is ≤ 5%;

[0078] S6, calculate the coupling coefficient and the coupling coefficient fluctuation rate;

[0079] S7, judging whether the coupling coefficient and the coupling coefficient fluctuation rate meet the requirements: comparing the current coupling coefficient and the coupling coefficient fluctuation rate with the set values, if they meet the requirements, saving the parameters that meet the conditions; if they do not meet the requirements, further adjusting the device parameters;

[0080] S8, repeat the above steps S3 to S7 until all parameters reach the upper limit.

[0081] As a preferred embodiment of the above embodiment, in S4, the self-inductance of the transmitting coil and the receiving coil is calculated according to the rectangular coil self-inductance calculation formula 1;

[0082] Formula 1 is:

[0083]

[0084] Among them: B 4z is the magnetic flux density, D is T x and R x Transmission distance between 0 is the vacuum permeability, a 1 and a 2 are the length and width of the transmitting coil, ξ and η are the double Fourier transform parameters, I is the excitation current added to the transmitting coil, and t represents time.

[0085] As a preferred embodiment of the above embodiment,

[0086] Under different coil offsets, the mutual inductance between single-turn rectangular coils is calculated according to the mutual inductance formula 2 between single-turn rectangular coils;

[0087] Formula 2 is:

[0088]

[0089] Where: B is the magnetic flux density, I is the excitation current added to the transmitting coil, b 1d and b 2d is the offset distance along the X-axis and Y-axis, b 1 and b 2 It's Coil 2 The length and width of ξ and η are the double Fourier transform parameters, S 2 is the vertical distance between the receiving coil and the ground, C iz and C ix is an intermediate variable, and its specific expressions are shown in formulas (3) and (4).

[0090] Formula (3) is:

[0091]

[0092] C iz It represents a complex number related to the geometry of the coil, the excitation current, the spatial frequency, and the distance between the coil and the ground. It takes into account the influence of the vertical direction of the coil when calculating the mutual inductance.

[0093] Formula (4) is:

[0094]

[0095] C ix represents another complex number related to the geometry of the coil, the excitation current, the spatial frequency, and the distance between the coil and the ground. It takes into account the horizontal direction of the coil when calculating the mutual inductance and contains an imaginary unit j, which is usually related to the phase change or time change.

[0096] in: μ 0 is the magnetic permeability in vacuum, I is the excitation current added to the transmitting coil, Z 0 is the vertical distance between the transmitting coil and the ground, It is an exponential term, which represents the propagation attenuation of electromagnetic waves in space.

[0097] These two intermediate variables C iz and C ix Used to calculate the mutual inductance M between the two coils 11 , which are combined together through integral expressions to take into account the spatial relationship and electromagnetic interactions between the coils.

[0098] As a preferred embodiment of the above embodiment, the total mutual inductance value is calculated according to the mutual inductance calculation formula 3 between the multi-turn coils;

[0099] Formula 3 is:

[0100] Where: N 1 and N 2 are the number of turns of the transmitting coil and the receiving coil respectively, m is the mth turn of the transmitting coil, and n is the nth turn of the receiving coil.

[0101] The following is a specific embodiment, which describes in detail the implementation process of the entire technical solution.

[0102] 1 System composition

[0103] The system includes a grid-side rectifier, an inverter, a transmitting coil, a receiving coil, a multi-dimensional mobile platform, and a vision-guided camera. The multi-dimensional mobile platform is responsible for adjusting the position and angle of the transmitting coil to achieve precise alignment with the receiving coil.

[0104] 2 System parameter settings

[0105] Copper wire diameter: 4mm

[0106] Resonant frequency: 85kHz

[0107] Initial distance between transmitting coil and receiving coil: 15cm

[0108] 3 Implementation of coupling coefficient optimization algorithm

[0109] S1. Model building

[0110] Create a model of a transmitting coil and a receiving coil that is larger than the transmitting coil and parallel to the transmitting coil.

[0111] S2. Set the main parameters

[0112] Based on the above parameters, we make the following calculations:

[0113] Self-inductance calculation (Formula 1):

[0114]

[0115] Among them, μ 0 is the vacuum permeability (4π×10 -7 H / m), a 1 and a 2 are the length and width of the transmitting coil (0.6 m and 0.6 m), and I is the excitation current (10 A).

[0116] Mutual inductance calculation (Formula 2):

[0117]

[0118] Among them, b 1 and b 2 is the length and width of the receiving coil (0.26m and 0.26m), d is the distance between the coils (0.15m), C iz and C ix is an intermediate variable.

[0119] Intermediate variable calculation (Formulas 3 and 4):

[0120]

[0121]

[0122] Parameter explanation:

[0123]

[0124] μ 0 : Magnetic permeability in vacuum

[0125] I: Excitation current added to the transmitting coil

[0126] z 0 : The vertical distance between the transmitting coil and the ground

[0127] is an exponential term, which represents the propagation attenuation of electromagnetic waves in space

[0128] Total mutual inductance calculation (Formula 5):

[0129]

[0130] Among them, N 1 and N 2 are the number of turns of the transmitting coil and the receiving coil respectively.

[0131] S3. Set specification constraints

[0132] According to the actual application and design requirements, the optimal range of setting the coil is shown in Table 1 below.

[0133] Table 1 Optimization range of coil parameters

[0134]

[0135] S4. Calculate mutual inductance and self-inductance

[0136] Use the above formula to calculate the mutual inductance and self-inductance values ​​of the transmitting coil and the receiving coil.

[0137] S5. Set the coupling coefficient k and the coupling coefficient fluctuation rate requirements

[0138] The coupling coefficient k is set to be ≧0.10; when the lateral offset is 3 cm, the coupling coefficient fluctuation rate is ≤5%; when the longitudinal offset is 3 cm, the coupling coefficient fluctuation rate is ≤5%.

[0139] S6. Calculation of coupling coefficient and coupling coefficient fluctuation rate

[0140] According to the calculation results, the coupling coefficient and coupling coefficient fluctuation rate are obtained.

[0141] S7. Determine whether the coupling coefficient and coupling coefficient fluctuation rate meet the requirements

[0142] The current coupling coefficient and coupling coefficient fluctuation rate are compared with the set values. If the requirements are met, the parameters that meet the conditions are saved; if the requirements are not met, the device parameters are further adjusted.

[0143] S8. Repeat the above steps

[0144] Repeat steps S3 to S7 until all parameters reach the upper limit.

[0145] 2.4 Implementation Results

[0146] Through the above embodiments, we obtain the self-inductance, mutual inductance and coupling coefficient of the transmitting coil and the receiving coil. Through the optimization algorithm, we ensure that the coupling coefficient can remain basically constant even when the transmitting coil and the receiving coil are offset. The specific values ​​are shown in Table 2 and Table 3 below:

[0147] Table 2 Coupling coefficient and error when offset along the lateral direction

[0148]

[0149] Table 3 Coupling coefficient and error when offset along the longitudinal direction

[0150]

[0151] It can be seen from the above table that the coupling coefficients are all greater than 0.10, the error of the coupling coefficients is 0.39% when offset along the lateral direction, and the error of the coupling coefficients is 0.19% when offset along the lateral direction, both of which are less than 5%. These data prove that the present invention has the corresponding technical effect, that is, when the transmitting coil and the receiving coil are offset, the coupling coefficient remains basically unchanged, thereby achieving efficient and stable wireless charging.

[0152] like Figure 2 As shown, a vehicle automatic charging method based on strong coupling wireless charging technology is used in a vehicle automatic charging system, comprising the following steps:

[0153] S1, set the X, Y, Z axis coordinate error and angle rotation error requirements: set the error between the actual coordinate in the X direction and the set coordinate to be less than 3cm; set the error between the actual coordinate in the Y direction and the set coordinate to be less than 3cm; set the error between the actual coordinate in the Z direction and the set coordinate to be less than 0.1cm;

[0154] S2, after the electric vehicle arrives at the parking area, the visually guided camera searches for the position of the receiving coil on the electric vehicle to obtain the coordinate position and deflection angle of the receiving coil;

[0155] S3, the controller obtains the coordinate position of the receiving coil, drives the multi-dimensional mobile platform to move, and adjusts the position of the transmitting coil so that the transmitting coil is basically aligned with the receiving coil;

[0156] S4, control the transmitting coil to flip through the multi-dimensional mobile platform, so that the foreign matter on the surface slides off, so as to achieve the goal of removing the foreign matter on the transmitting coil, and then reset;

[0157] S5, then controlling the transmitting coil and the receiving coil to gradually fit closely together through the multi-dimensional mobile platform;

[0158] S6, repeat the above steps S2 to S5 until all coordinate position parameters reach the set target.

[0159] The working principle of the present invention is as follows:

[0160] When the electric car stops, the vision-guided camera on the transmitting coil side captures the position information of the receiving coil, and then transmits the position information to the multi-dimensional mobile platform. The multi-dimensional mobile platform adjusts the position of the transmitting coil in real time so that the transmitting coil and the receiving coil are aligned and fit tightly.

[0161] Based on the wireless charging system, the vision-guided camera positioning device and the multi-dimensional mobile platform are used to make the transmitting coil and the receiving coil accurately aligned and tightly fit. Combined with the coupling coefficient optimization algorithm of the transmitting coil and the receiving coil, even if the receiving coil and the transmitting coil of the wireless charging system are offset within a large range, the coupling coefficient between the receiving coil and the transmitting coil remains basically unchanged, thus completing automatic charging.

[0162] By using a multi-dimensional mobile platform to flip the transmitting coil 90 degrees, foreign matter can be made to slide off, thus achieving the goal of removing metal foreign matter from the transmitting coil.

[0163] Preferred embodiments of the invention are described herein, including the best mode known to the inventor for carrying out the invention. Variations of the preferred embodiments will be apparent to one of ordinary skill in the art upon reading the foregoing description. The inventors expect that such variations will be reasonably applied by those of ordinary skill, and the inventors believe that the invention may be practiced in applications other than those expressly described herein. Therefore, the present invention includes all modifications and equivalents of the subject matter cited in the appended claims, as permitted by applicable law. In addition, any combination of all possible variations of the above elements is also encompassed by the present invention, unless otherwise noted herein or clearly contradicted in context.

[0164] It should be noted that, in this article, the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus.

[0165] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. The above is only a preferred implementation of the present invention. It should be pointed out that due to the limitations of textual expression and the objective existence of infinite specific structures, ordinary technicians in this technical field can make several improvements, modifications or changes without departing from the principles of the present invention, and can also combine the above technical features in an appropriate manner; these improvements, modifications, changes or combinations, or the direct application of the inventive concept and technical solution to other occasions without improvement, should be regarded as the protection scope of the present invention.

Claims

1. An automatic automobile charging system based on strong coupling wireless charging technology, comprising a grid-side rectifier, an inverter, a transmitting coil, and a receiving coil, characterized in that: It also includes a multi-dimensional mobile platform and a vision-guided camera. The position of the receiving coil is obtained by the vision-guided camera, and the movement of the multi-dimensional mobile platform is controlled by a controller. The coupling coefficient optimization algorithm of the transmitting coil and the receiving coil is used to make the transmitting coil and the receiving coil of the wireless charging system accurately aligned and tightly fit. Even if the receiving coil and the transmitting coil are offset, the coupling coefficient between the receiving coil and the transmitting coil can be kept basically unchanged, thereby completing automatic charging.

2. According to claim 1, the automatic charging system for automobiles based on strong coupling wireless charging technology is characterized in that: The multi-dimensional mobile platform realizes three-coordinate movement and angle adjustment of the transmitting coil.

3. According to claim 1, the automatic automobile charging system based on strong coupling wireless charging technology is characterized in that: The transmitting coil is flipped by controlling the multi-dimensional mobile platform so that foreign objects on the transmitting coil can slide off, thereby achieving the purpose of removing foreign objects.

4. According to claim 1, the automatic automobile charging system based on strong coupling wireless charging technology is characterized in that: The vision-guided camera and the transmitting coil are mounted on a multi-dimensional mobile platform.

5. According to claim 1, the automatic charging system for automobiles based on strong coupling wireless charging technology is characterized in that: The coupling coefficient optimization algorithm comprises the following steps: S1, establish a transmitting coil to receiving coil model: it consists of a transmitting coil and a receiving coil whose size is larger than the transmitting coil, and the receiving coil is parallel to the transmitting coil; S2, set the main parameters: including the diameter of the copper wire, the resonant frequency, and the distance between the transmitting coil and the receiving coil; S3, setting specification constraints: setting constraints according to actual application and design requirements; including the range of inner length of the transmitting coil, the range of inner width of the transmitting coil, the range of the number of turns of the transmitting coil, the range of inner length of the receiving coil, the range of inner width of the receiving coil, the range of the number of turns of the receiving coil, and the step size; S4, calculating the mutual inductance and self-inductance of the transmitting coil and the receiving coil; S5, set the coupling coefficient k and the coupling coefficient fluctuation rate requirements: set the coupling coefficient k ≥ 0.12; when the lateral offset is 3 cm, the coupling coefficient fluctuation rate is ≤ 5%; when the longitudinal offset is 3 cm, the coupling coefficient fluctuation rate is ≤ 5%; S6, calculate the coupling coefficient and the coupling coefficient fluctuation rate; S7, judging whether the coupling coefficient and the coupling coefficient fluctuation rate meet the requirements: comparing the current coupling coefficient and the coupling coefficient fluctuation rate with the set values, if they meet the requirements, saving the parameters that meet the conditions; if they do not meet the requirements, further adjusting the device parameters; S8, repeat the above steps S3 to S7 until all parameters reach the upper limit.

6. The automobile automatic charging system based on strong coupling wireless charging technology according to claim 5 is characterized in that: In S4, the self-inductance of the transmitting coil and the receiving coil is calculated according to the rectangular coil self-inductance calculation formula (1); Formula (1) is: Among them: B 4z is the magnetic flux density, D is T x and R x The transmission distance between them, μ0 is the vacuum magnetic permeability, a1 and a2 are the length and width of the transmitting coil, ξ and η are the double Fourier transform parameters, I is the excitation current added to the transmitting coil, and t represents time.

7. The automobile automatic charging system based on strong coupling wireless charging technology according to claim 6 is characterized in that: Under different coil offsets, the mutual inductance between single-turn rectangular coils is calculated according to the mutual inductance formula (2) between single-turn rectangular coils; Formula (2) is: Where: B is the magnetic flux density, I is the excitation current added to the transmitting coil, b 1d and b 2d is the offset distance along the X-axis and Y-axis, b1 and b2 are the length and width of Coil2, ξ and η are the double Fourier transform parameters, S2 is the vertical distance between the receiving coil and the ground, C iz and C ix is an intermediate variable, and its specific expressions are shown in formulas (3) and (4): Formula (3) is: Formula (4) is: Where: j is an imaginary unit, representing the square root of -1, μ0 is the magnetic permeability in vacuum, I is the excitation current added to the transmitting coil, Z0 is the vertical distance between the transmitting coil and the ground, It is an exponential term, which represents the propagation attenuation of electromagnetic waves in space.

8. The automobile automatic charging system based on strong coupling wireless charging technology according to claim 7 is characterized in that: The total mutual inductance value is calculated according to the mutual inductance calculation formula (5) between the multi-turn coils; Formula (5) is: Where: N1 and N2 are the number of turns of the transmitting coil and the receiving coil respectively, m is the mth turn of the transmitting coil, and n is the nth turn of the receiving coil.

9. An automatic vehicle charging method based on strong coupling wireless charging technology, used in the automatic vehicle charging system according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1, set the X, Y, Z axis coordinate error and angle rotation error requirements: set the error between the actual coordinate in the X direction and the set coordinate to be less than 3cm; set the error between the actual coordinate in the Y direction and the set coordinate to be less than 3cm; set the error between the actual coordinate in the Z direction and the set coordinate to be less than 0.1cm; S2, after the electric vehicle arrives at the parking area, the visually guided camera searches for the position of the receiving coil on the electric vehicle to obtain the coordinate position and deflection angle of the receiving coil; S3, the controller obtains the coordinate position of the receiving coil, drives the multi-dimensional mobile platform to move, and adjusts the position of the transmitting coil so that the transmitting coil is basically aligned with the receiving coil; S4, control the transmitting coil to flip through the multi-dimensional mobile platform, so that the foreign matter on the surface slides off, so as to achieve the goal of removing the foreign matter on the transmitting coil, and then reset; S5, then controlling the transmitting coil and the receiving coil to gradually fit closely together through the multi-dimensional mobile platform; S6, repeat the above steps S2 to S5 until all coordinate position parameters reach the set target.

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