Method for optimizing composite magnetic coupling structure of GIS (gas insulated switchgear) switch state judgment device

Abstract

The invention discloses a compound type magnetic coupling structure optimization method of a GIS switch state judgment device, and relates to the field of magnetic coupling structure optimization methods, and the method comprises the steps: detecting the on / off state of a GIS isolation / grounding switch through a video detection system; the wireless power transmission technology is used for supplying power to the video detection system; the wireless energy supply coil in the wireless electric energy transmission technology is optimized by the following steps of: 1, optimizing a magnetic coupling mechanism, namely optimizing the magnetic coupling mechanism for wireless electric energy transmission; the second step of analyzing the magnetic field of the asymmetric coil specifically comprises the following steps that S201, the distribution condition of the magnetic field around the coil is known, and the third step of optimizing parameters of the asymmetric coil, the magnetic core structure, the magnetic core parameters and arrangement; and the volume of the magnetic core material is reduced to the greatest extent while higher mutual inductance, coupling coefficient and anti-offset performance are obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of magnetic coupling structure optimization methods, and in particular to a composite magnetic coupling structure optimization method for a GIS switch state judgment device. Background Art

[0002] Because GIS equipment is a sealed device, compared with traditional open equipment, the contact status of the contacts cannot be directly observed, and it is impossible to intuitively determine whether the GIS isolation / earthing switch contacts are in place. During operation, if the contacts are not in place, it will cause equipment accidents, resulting in economic losses and even endangering personal safety. In addition, when a GIS equipment accident occurs, it is difficult to handle, power restoration is slow, and the cost of accident handling is high, which brings great hidden dangers to its use. Therefore, it is very important to accurately determine whether the GIS isolation / earthing switch is actually extended and retracted during operation. For GIS equipment with observation holes, image recognition can be used to detect the switch status. Therefore, the power supply of the sensor becomes an important issue to ensure the long-term operation of the device.

[0003] Magnetic coupling resonant wireless power transfer technology has attracted considerable research attention in recent years, with broad application prospects in electric vehicles, household appliances, and medical equipment.

[0004] The magnetic coupling mechanism is a key component of the resonant wireless power transmission system and largely determines the transmission performance of the system.

[0005] The following technologies exist in the prior art:

[0006] The first technology: With the goal of increasing the coupling coefficient of the planar circular coil, the inner-outer diameter ratio of the coil was studied based on the substrate ferrite thickness, turn spacing, coil spacing, and horizontal offset. Ultimately, it was concluded that the inner-outer diameter ratio of the coil should not be greater than 0.4.

[0007] The second technology: For the design of the ferrite structure of the coupling coil in the dynamic wireless power transmission system, based on the minimization of the oscillation of the coupling parameters along the aircraft trajectory and the balance between the coupling performance and the volume of the ferrite, a non-uniform ferrite structure of the rectangular coil is proposed. Compared with the uniform arrangement scheme, while saving 58.9% of the ferrite volume, the maximum mutual inductance is reduced by about 20%.

[0008] The third technology proposes an optimized method for integrating leakage magnetic fields into the ferrite double-D liner on the transmitting side of a high-power wireless power transmission system. This liner, composed of ferrite and a soft magnetic composite material, not only significantly reduces the ferrite volume but also shields the leakage magnetic field. While significantly reducing magnetic field leakage and ferrite volume, the coupling coefficient only decreases by 3%.

[0009] However, there is still room for improvement in terms of minimizing the volume of the core material while achieving higher mutual inductance, coupling coefficient and anti-offset performance.

[0010] To this end, we provide a composite magnetic coupling structure optimization method for GIS switch state judgment device to solve the above problems. Summary of the Invention

[0011] In response to the problems existing in the above-mentioned prior art, the present invention provides a composite magnetic coupling structure optimization method for a GIS switch state judgment device. The present invention optimizes the magnetic coupling mechanism of resonant wireless power transmission, explores the influencing parameters of the optimal outer radius of the receiving coil from the perspective of system basic principles, modeling analysis, and spatial magnetic field analysis, and optimizes the magnetic coupling mechanism. In terms of optimizing the magnetic coupling mechanism, the structure and parameters of the coil are optimized, and the structure and parameters of the magnetic core are further compared and analyzed. While obtaining higher mutual inductance, coupling coefficient, and anti-offset performance, the volume of the magnetic core material is minimized to the greatest extent.

[0012] In order to achieve the above-mentioned purpose, the present invention adopts a composite magnetic coupling structure optimization method of a GIS switch state judgment device, which uses a video detection system to detect the open / closed state of the GIS isolation / grounding switch;

[0013] Use wireless power transmission technology to supply power to the video detection system;

[0014] Optimize the wireless power supply coil in wireless power transmission technology:

[0015] Step 1: Optimize the magnetic coupling mechanism of wireless power transmission;

[0016] Step 2: Analyze the magnetic field of the asymmetric coil, which includes the following steps:

[0017] S201, understanding the distribution of the magnetic field around the coil;

[0018] Step 3: Optimize the asymmetric coil parameters, core structure, core parameters and layout, including the following steps:

[0019] S301: Analyze the magnetic field distribution around the coil, compare the magnetic permeability and saturation magnetic induction parameters of different core materials, select the appropriate core material and structure, determine the inductance, magnetic resistance, and loss parameters of the core, and understand the distribution of the magnetic field inside the core;

[0020] S302, calculate and optimize the inductance and magnetic resistance parameters of the magnetic core. The calculation formula of the inductance includes:

[0021] Magnetic induction intensity

[0022] Where μ0 is the magnetic permeability of vacuum;

[0023] I is the current intensity, the unit is ampere (A);

[0024] is the current element vector, its direction is the direction of current, and its magnitude is the product of current intensity and length;

[0025] is the position vector, its direction is from the current element to the observation point, and its magnitude is the distance between the current element and the observation point;

[0026] r is the distance from point P to the current element;

[0027] Take any point P(x,y,z) above the space and any point A(x1,y1,0) on the single-turn circular coil. β is the angle between point A and the positive direction of the x-axis. Then the current element at point A and the radius vectors at points P and A are:

[0028]

[0029]

[0030] in, is the current element vector, I is the current intensity, is the position vector, R is the radius of the ring, i, j, k are the positive directions of the unit vector along the x, y, and z axes respectively;

[0031] The magnetic field component B in the z-axis direction Z for:

[0032]

[0033] Where Z is the distance of point P in the vertical direction.

[0034] Assume that the height of point P from the xoy plane is H (i.e., Z = H), and it is located in a circular area with a radius of r (i.e., y = r), then the coordinates of the center of the circular area are (0, 0, H), and the B generated by any point on the same circle is Z With the same size, assuming that point P is on the yoz plane (x=0), the magnetic induction intensity B generated at point P is Z for:

[0035]

[0036] Simplified:

[0037] Where E represents the voltage generated by the Hall effect; K is the sensitivity of the Hall device, which is a constant representing the voltage per volt generated by the product of one ampere of current and one tesla of magnetic field; the symbol K (k) represents the proportionality coefficient.

[0038] For a planar circular coil with n turns, it is equivalent to n concentric circles with equal spacing. The radius of the outermost circular coil is R, and the spacing between the coil turns is d. Then the magnetic induction intensity generated on a circle with a radius of r above the space is expressed as:

[0039]

[0040]

[0041] The magnetic flux generated Expressed as:

[0042]

[0043] To provide an analytical basis for the subsequent optimization of the WPT system coupling mechanism, the spatial magnetic field generated by the coil in the mechanism is analyzed. After simulating and analyzing the magnetic field of a single-turn planar coil using Maxwell software, it is further superimposed and expanded to simulate the spatial electromagnetic field of the composite coil. After deriving the n-turn circular coil, the maximum value of the magnetic flux linkage and the optimal outer radius of the receiving coil are determined.

[0044] As a further optimization of the above solution, a method for detecting the open / closed state of the GIS isolation / grounding switch using a video detection system specifically includes the following steps:

[0045] Step 1: The image sensor installed in the optical observation window of the GIS equipment acquires image data, and then transmits the data to the client for real-time processing through the video sending module;

[0046] Step 2: Combining OpenCV and the three-frame difference method, when preparing for the opening and closing operations, the server and client of the GIS device are initialized and ready to send and receive data;

[0047] Step 3: The client obtains the transmitted image, pre-processes the image based on OpenCV, then uses the three-frame difference method to track the movement of the switch moving contact, and finally determines the switch state based on the current position and movement direction of the current moving contact.

[0048] As a further optimization of the above scheme, in the asymmetric coil parameters, the inner radius of the transmitting coil and the receiving coil are both set to 80 mm, the outer radius of the transmitting coil is 150 mm, and the transmission distance is 100 mm. From formulas (7) to (9), the derivative of the total magnetic flux passing through the receiving coil shows that when the outer radius of the receiving coil is 212 mm, the magnetic flux reaches its maximum value, that is, 212 mm is the outer radius of the receiving coil.

[0049] The composite magnetic coupling structure optimization method of the GIS switch state judgment device of the present invention has the following beneficial effects:

[0050] The composite magnetic coupling structure optimization method for the GIS switch state judgment device of the present invention optimizes the magnetic coupling mechanism of resonant wireless power transmission. From the basic principles of the system, modeling analysis, and spatial magnetic field analysis, the influencing parameters of the optimal outer radius of the receiving coil are explored. In terms of optimizing the magnetic coupling mechanism, the structure and parameters of the coil are optimized, and the magnetic core structure and parameters are further compared and analyzed. While achieving higher mutual inductance, coupling coefficient, and anti-offset performance, the volume of the magnetic core material is minimized to the greatest extent.

[0051] With reference to the following description and drawings, specific embodiments of the present invention are disclosed in detail, indicating how the principles of the present invention can be adopted. It should be understood that the scope of the embodiments of the present invention is not limited thereby, and the embodiments of the present invention include many changes, modifications and equivalents within the spirit and scope of the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 FIG. 1 is a diagram of a video detection system of the present invention;

[0053] Figure 2 This is a flow chart of the method for optimizing the magnetic coupling mechanism of resonant wireless power transmission of the present invention;

[0054] Figure 3 A schematic diagram of a single-turn circular coil of the present invention;

[0055] Figure 4 This is a relationship diagram between the outer radius of the receiving coil and the coil parameters of the present invention;

[0056] Figure 5 This is a diagram showing the relationship between the horizontal offset distance of the receiving coil and the coil parameters of the present invention;

[0057] Figure 6 Schematic diagram of the structure of nine magnetic core structures of the receiving coil of the present invention;

[0058] Figure 7 Schematic diagram of the variation curve of the mutual inductance between coils with the horizontal offset distance between coils under the nine magnetic core structures of the present invention;

[0059] Figure 8 Schematic diagram of the curve showing the change of the coupling coefficient between coils with the horizontal offset distance between coils under the nine magnetic core structures of the present invention;

[0060] Figure 9 Schematic diagram showing the effect of ferrite thickness on coupling coefficient of the present invention;

[0061] Figure 10 Schematic diagram showing the effect of the ferrite coil spacing on the coupling coefficient of the present invention;

[0062] Figure 11 This is a comparison diagram of coil parameters before and after optimization of structure 3 of the present invention;

[0063] Figure 12 This is a comparison diagram of coil parameters before and after optimization of structure 4 of the present invention;

[0064] Figure 13 This is a comparison diagram of coil parameters before and after optimization of structure 5 of the present invention;

[0065] Figure 14 This is a comparison diagram of coil parameters before and after optimization of structure 6 of the present invention. DETAILED DESCRIPTION

[0066] Please refer to the instruction manual Figure 1-14 The present invention provides a technical solution: a composite magnetic coupling structure optimization method for a GIS switch state judgment device.

[0067] like Figure 1 As shown in the figure, the purpose of using a video detection system is to detect the open / closed state of the GIS isolation / earthing switch. First, the CMOS sensor (image sensor) installed in the optical observation window of the GIS device acquires image data, and then transmits the data to the terminal (client) via wireless transmission (video transmission module) for real-time processing. In combination with OpenCV and the three-frame difference method, when preparing for the opening and closing operations, the server and client of the GIS device are initialized and ready to send and receive data. The client obtains the transmitted image, pre-processes the image based on OpenCV, and then uses the three-frame difference method to track the movement of the switch moving contact. Finally, the switch state is determined based on the current position and movement direction of the current moving contact.

[0068] Asymmetric coil structure design based on optimal outer radius:

[0069] In order to achieve reliable power supply for the auxiliary judgment device (video detection system), combined with the structural characteristics of GIS equipment, the present invention adopts wireless power transmission technology to supply power to the auxiliary judgment device. This step mainly optimizes the design of the wireless power supply coil.

[0070] refer to Figure 2As shown in , it is a flow chart of the method for optimizing the magnetic coupling mechanism of resonant wireless power transmission.

[0071] The process of optimizing the magnetic coupling mechanism of resonant wireless power transmission is as follows:

[0072] Step 1: Optimization of magnetic coupling mechanism;

[0073] Step 2: Asymmetric coil magnetic field analysis;

[0074] Step 3: Optimize the design of asymmetric coil parameters, core structure, core parameters and layout.

[0075] Advantages of asymmetric coil magnetic field analysis:

[0076] In coil parameter design, magnetic field analysis helps determine parameters such as the number of turns, wire diameter, and current density to meet specific electromagnetic performance requirements. This analysis can help understand the distribution of the magnetic field around the coil, thereby optimizing the coil structure and parameters, and improving coil efficiency and performance.

[0077] In the design of magnetic core structures and parameters, magnetic field analysis can be used to evaluate the performance and advantages and disadvantages of different core structures. Through magnetic field analysis, parameters such as the magnetic permeability and saturation magnetic induction intensity of different core materials can be compared to select the most suitable core material and structure. Magnetic field analysis can determine core parameters such as inductance, reluctance, and loss. This provides further insight into the distribution of the magnetic field within the core, allowing calculation and optimization of core parameters such as inductance and reluctance. Furthermore, magnetic field analysis helps evaluate the core's loss characteristics and select the appropriate core material and structure to reduce core losses and improve efficiency.

[0078] With the center O as the origin, and the straight line perpendicular to the plane and passing through the center O as the z-axis, establish Figure 3 The coordinate system shown is such that the circular plane coincides with the xoy plane. Assuming the radius of the ring is R and the current is I, according to the Biot-Savart law:

[0079]

[0080] Where μ0 is the vacuum permeability, which is a constant approximately equal to 4π×10^{-7}H / m;

[0081] I is the current intensity, the unit is ampere (A);

[0082] is the current element vector, also called the current infinitesimal vector, its direction is the direction of the current, and its magnitude is the product of the current intensity and the length;

[0083] is the position vector, also called the radius vector, whose direction is from the current element to the observation point, and its magnitude is the distance between the current element and the observation point;

[0084] is the magnetic induction intensity, and r is the distance from point P to the current element.

[0085] Take any point P(x,y,z) above the space and any point A(x1,y1,0) on the single-turn circular coil. β is the angle between point A and the positive direction of the x-axis. Then the current element at point A and the radius vectors at points P and A are:

[0086]

[0087]

[0088] in, is the current element vector, I is the current intensity, is the position vector, R is the radius of the ring, i, j, k are the positive directions of the unit vector along the x, y, and z axes respectively;

[0089] Then its magnetic field component B in the z-axis direction z for:

[0090]

[0091] Where Z is the distance of point P in the vertical direction.

[0092] Assume that the height of point P from the xoy plane is H (i.e., Z=H), and it is located in a circular area with a radius of r (i.e., y=r), then the coordinates of the center of the circular area are (0, 0, H). z have the same size, so first assume that point P is on the yoz plane (x=0), then the magnetic induction intensity B generated at point P is z for:

[0093]

[0094] Simplified:

[0095] Where E represents the voltage generated by the Hall effect; K is the sensitivity of the Hall device, which is a constant with the unit of V / (A·T), indicating the voltage generated per volt per ampere of current multiplied by the magnetic field per tesla; the symbol K (k) represents the proportionality coefficient.

[0096] For a planar circular coil with n turns, it can be equivalent to n concentric circles with equal spacing. The radius of the outermost circular coil is R, and the spacing between the coil turns is d. Then the magnetic induction intensity generated on a circle with a radius of r above the space can be expressed as:

[0097]

[0098]

[0099]

[0100] The magnetic flux generated It can be expressed as:

[0101]

[0102] To provide an analytical basis for subsequent optimization of the WPT system coupling mechanism, the spatial magnetic field generated by the coils in this mechanism was analyzed. After simulating and analyzing the magnetic field of a single-turn planar coil using Maxwell software, this field was further superimposed and expanded to simulate the spatial electromagnetic field of a composite coil. By deriving an n-turn circular coil, the maximum flux linkage and the optimal outer radius of the receiving coil can be determined.

[0103] Asymmetric coil parameter design:

[0104] The inner radius of the transmitting coil and the receiving coil are both set to 80 mm, the outer radius of the transmitting coil is 150 mm, and the transmission distance is 100 mm. From formulas (7) to (9), the derivative of the total magnetic flux passing through the receiving coil shows that when the outer radius of the receiving coil is 212 mm, the magnetic flux reaches its maximum value, that is, 212 mm is the optimal outer radius of the receiving coil.

[0105] The Maxwell finite element simulation verifies that when the outer radius of the receiving coil changes, the changes in the coil coupling coefficient and mutual inductance are shown in the attached figure. Figure 4 shown.

[0106] By the attached Figure 4 It can be seen that the theoretically calculated value of the optimal outer radius of the receiving coil is 212mm, which corresponds to a coupling coefficient and mutual inductance of 0.2294μH and 6.609μH, respectively, which differ from the maximum values ​​of 0.2300μH and 6.657μH by approximately 0.72% and 0.26%, respectively. Considering that when the outer radius of the receiving coil is greater than 200mm, the growth of the coupling coefficient and mutual inductance gradually slows down, the outer radius is set to 200mm. The corresponding relationship between the coupling coefficient, mutual inductance and horizontal offset distance is shown in the attached figure. Figure 5 As shown in the figure, when the coils are aligned, the coupling coefficient and mutual inductance are 0.2277μH and 6.536μH respectively.

[0107] Optimized design of magnetic core structure:

[0108] Wireless power transmission technology is complex and highly dependent on both the coil structure and parameter design, as well as the ferrite core structure. Proper ferrite core design can achieve low-cost, lightweight, and standardized power transmission for WPT systems. Coil design and ferrite core shape are crucial to transmission efficiency. The high magnetic permeability of the ferrite core effectively reduces flux linkage, promoting good coupling between the transmitting and receiving coils. Proper ferrite core structural design and analysis can improve power transmission by increasing the coupling coefficient while also significantly reducing the overall system weight and volume.

[0109] The present invention uses the finite element analysis method to design nine different ferrite core structures and select the most suitable ferrite structure; then analyzes the influence of ferrite parameters and the distance from the coil on the system transmission parameters.

[0110] Core structure design:

[0111] Magnetic cores can significantly improve the coupling between the primary and secondary sides, and are therefore widely used in wireless power transmission systems. Figure 6 The figure shows nine core structures to be selected, including: pie-shaped, ring-shaped, ring-shaped with four strips, ring-shaped with eight strips, ring-shaped with twelve strips (ring-shaped and twelve strips alternating), ring-shaped with twelve strips (twelve strips located inside the ring), four strips, eight strips, and twelve strips.

[0112] Using the EddyCurrent solver in Ansys Maxwell, simulation models were established for 9 core structures (Structure 1, Structure 2, Structure 3...Structure 9, represented by 1, 2, 3...9 in Table 1 and Table 2, respectively) to compare and analyze the influence of the core structure on the mutual inductance and coupling coefficient, and then the optimized structure was determined. The parameters are shown in Table 1. Among them, the minimum distance from the strip core to the center point is set to 60mm, and the thickness of the strip core is set to 4mm. The horizontal offset distance between the transmitting coil and the receiving coil is set to vary in the range of 0 to 80mm, with a step size of 10mm. According to the finite element analysis results of Maxwell software, the curves of the mutual inductance and coupling coefficient between the coils under the 9 core structures as the horizontal offset distance between the coils changes are obtained as shown in the attached figure. Figure 7 and attached Figure 8 shown.

[0113] Table 1 Design parameters of nine core structures of receiving coil

[0114] serial number Inner radius / mm Outer radius / mm Number of strip cores Strip core length Strip core width 1 - 22 0 - - 2 10 20 0 - - 3 15 20 4 16 40 4 15 20 8 16 40 5 15 20 12 16 30 6 15 20 12 85 30 7 - - 4 16 70 8 - - 8 16 40 9 - - 12 16 30

[0115] like Figure 8 、 Figure 9 As shown in Table 2, the mutual inductance and coupling coefficient between coils in all nine core structure designs decrease with increasing horizontal offset distance. Structures 4, 5, and 9 exhibit relatively small decreases in mutual inductance when the coils are facing each other. Considering the core volume and its effect on mutual inductance, Structure 9, as a classic core design, performs well.

[0116] Table 2 Comparison of nine core structure parameters of receiving coils

[0117]

[0118] Core parameters and layout design:

[0119] The influence of ferrite thickness and ferrite coil spacing on the coupling coefficient is obtained from the Maxwell software modeling and simulation, as shown in the attached figure. Figure 9 and attached Figure 10 shown.

[0120] The present invention is designed to compare different core structures with fixed sizes. Therefore, based on the selection of structure 9, the influence of core parameter changes on the coil coupling coefficient and mutual inductance is further studied. Figure 9 and attached Figure 10 As shown, the ferrite thickness is set to 1-10mm with a step size of 1mm. The coupling coefficient and mutual inductance gradually increase with the increase of the ferrite thickness. When the ferrite thickness is 4mm, the growth trend slows down, so 4mm is still selected as the design thickness of the core; the distance between the ferrite and the coil is set to 1-31mm with a step size of 3mm. The coil coupling coefficient and mutual inductance decrease with the increase of the distance, so when arranging the ferrite, it should be as close to the coil as possible. Therefore, consider exchanging the upper and lower positions of the bar core and the annular core in design structures 3 to 5, and change the annular core to be located below the bar core; design structure 6 reduces the length of the bar core to 84mm and makes it coplanar with the annular core. Use Maxwell software modeling and analysis to study the relationship between the coil coupling coefficient and mutual inductance with the horizontal offset distance before and after optimization, and then determine the optimized core structure parameters, as shown in the attached figure. Figure 11 To the attached Figure 14 shown.

[0121] Table 3 Comparison of receiving coil core structure parameters (numbered with "*" indicates the optimized structure of the corresponding core structure)

[0122]

[0123]

[0124] When the coils are facing each other, the mutual inductance of design structures 3-6 is increased by 1.1%, 2.6%, 3.0%, and 3.8% respectively after optimized arrangement. At this time, when design structures 4 and 5 are facing each other, the mutual inductance decrease rate is the smallest, which is 9.6% and 7.9% respectively. Taking into account the magnetic core saving rate, the present invention finally selects structure 4 as the magnetic core structure design scheme.

[0125] This paper addresses the power supply issues of the auxiliary judgment device for GIS switch status and proposes the use of wireless power transmission technology to supplement the power supply of the auxiliary judgment device, thereby improving its continuous operation capability. Considering the limited space of the observation window of GIS equipment, this paper optimizes the design of the wireless power transmission system. The specific contents include:

[0126] Based on the analysis of the basic principles and modeling of the system, the optimization of the magnetic coupling mechanism was studied. The coil parameters were optimized by combining the concept of the optimal outer radius of the receiving coil to determine the optimal size design of the coupling mechanism coil.

[0127] With the aim of saving space and ferrite materials and ensuring that the mutual inductance decreases as little as possible, nine ferrite coupling mechanism parameters that change with the horizontal offset of the coupling mechanism were proposed and compared. Then, the best core structure was selected through finite element simulation, resulting in a mutual inductance reduction rate of 9.6%, saving about 38.59% of the core usage.

Claims

1. A composite magnetic coupling structure optimization method for a GIS switch state judgment device, characterized in that: Use the video detection system to detect the open / closed status of the GIS isolation / earthing switch; Use wireless power transmission technology to supply power to the video detection system; Optimize the wireless power supply coil in wireless power transmission technology: Step 1: Optimize the magnetic coupling mechanism, optimize the magnetic coupling mechanism of wireless power transmission; Step 2: Analyze the magnetic field of the asymmetric coil, which includes the following steps: S201, understanding the distribution of the magnetic field around the coil; Step 3: Optimize the asymmetric coil parameters, core structure, core parameters and layout, including the following steps: S301, by analyzing the magnetic field distribution around the coil, comparing the magnetic permeability and saturation magnetic induction parameters of different magnetic core materials, selecting a suitable magnetic core material and structure, determining the inductance, magnetic resistance, and loss parameters of the magnetic core, and understanding the distribution of the magnetic field inside the magnetic core; S302, calculating and optimizing the inductance and magnetic resistance parameters of the magnetic core, the calculation formula of the inductance includes: Magnetic induction intensity Where, μ0 is the magnetic permeability of vacuum; I is the current intensity, the unit is ampere (A); is the current element vector, its direction is the direction of the current, and its magnitude is the product of the current intensity and the length; is the position vector, its direction is from the current element to the observation point, and its magnitude is the distance between the current element and the observation point; r is the distance from point P to the current element; Take any point P(x,y,z) above the space, and any point A(x1,y1,0) on the single-turn circular coil. β is the angle between point A and the positive direction of the x-axis. Then the current element at point A and the radius vectors at points P and A are: in, is the current element vector, I is the current intensity, is the position vector, R is the radius of the ring, i, j, k are the positive directions of the unit vector along the x, y, z axes respectively; The magnetic field component B in the z-axis direction z for: Where Z is the distance of point P in the vertical direction; Assume that the height of point P from the xoy plane is H (i.e., Z = H), and that it is located in a circular area with a radius of r (i.e., y = r), then the coordinates of the center of the circular area are (0, 0, H), and the B generated by any point on the same circle is z have the same size. Assuming that point P is on the yoz plane (x=0), the magnetic induction intensity B generated at point P is z for: Simplified: Where E represents the voltage generated by the Hall effect; K is the sensitivity of the Hall device, which is a constant indicating the voltage generated per volt for each ampere of current multiplied by each Tesla of magnetic field; the symbol K(k) represents the proportionality coefficient; For a planar circular coil with n turns, it is equivalent to n concentric circles with equal spacing, where the radius of the outermost circular coil is R and the coil turn spacing is d. The magnetic induction intensity generated on a circle with a radius of r above the space is expressed as: The magnetic flux generated It is expressed as: In order to provide an analytical basis for the subsequent optimization of the coupling mechanism of the WPT system, the spatial magnetic field generated by the coil in the mechanism is analyzed. After simulating and analyzing the magnetic field of a single-turn planar coil using Maxwell software, it is further superimposed and expanded to simulate the spatial electromagnetic field of the composite coil. After deriving the n-turn circular coil, the maximum value of the magnetic flux linkage and the optimal outer radius of the receiving coil are determined.

2. The composite magnetic coupling structure optimization method of the GIS switch state judgment device according to claim 1 is characterized in that: The method of using a video detection system to detect the open / closed state of a GIS isolation / grounding switch specifically includes the following steps: Step 1: The image sensor installed in the optical observation window of the GIS equipment obtains image data, and then transmits the data to the client for real-time processing through the video sending module; Step 2: Combining OpenCV and the three-frame difference method, when preparing for the opening and closing operations, the server and client of the GIS device are initialized and ready to send and receive data; Step 3: The client obtains the transmitted image, pre-processes the image based on OpenCV, then uses the three-frame difference method to track the movement of the switch moving contact, and finally determines the switch state based on the current position and movement direction of the current moving contact.

3. The composite magnetic coupling structure optimization method of the GIS switch state judgment device according to claim 1 is characterized in that: In the asymmetric coil parameters, the inner radius of the transmitting coil and the receiving coil are set to 80 mm, the outer radius of the transmitting coil is 150 mm, and the transmission distance is 100 mm. From formulas (7) to (9), the derivative of the total magnetic flux passing through the receiving coil shows that when the outer radius of the receiving coil is 212 mm, the magnetic flux reaches the maximum value, that is, 212 mm is the outer radius of the receiving coil.

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