Method and device for determining equivalent lumped parasitic capacitance of magnetic core current sensor

Abstract

The invention discloses a method and device for determining equivalent lumped stray capacitance of a magnetic core current sensor, and relates to the field of electric power measurement, and the method comprises the steps: determining electric field distribution based on determined design parameters, so as to establish a distributed stray capacitance network; the electric field distribution is related to the dielectric constant of the magnetic core material in the design parameters; determining a strategy according to the turn-to-turn distance, the turn-to-magnetic core distance and a preset correction factor in the design parameters to obtain a target correction factor, further determining the capacitance value of the turn-to-turn capacitor at the head end and the tail end of each winding included in the distributed stray capacitance network, and obtaining a target equivalent lumped stray capacitance according to the capacitance value. According to the scheme, the dielectric constant, the turn-to-turn distance and the turn-to-magnetic core distance of the magnetic core material are considered, and then the target correction factor used for representing the nonlinear electric field coupling effect is determined, so that the determination precision of the target equivalent lumped parasitic capacitance is higher; the method can be suitable for determining the target equivalent lumped parasitic capacitance of magnetic core current sensors with various geometric sizes and magnetic core materials.

Description

Technical Field

[0001] The present invention relates to the technical field of power measurement, and in particular to a method and device for determining the equivalent lumped parasitic capacitance of a magnetic core current sensor. Background Art

[0002] As a non-contact current measurement device based on the principle of electromagnetic induction, the toroidal current sensor is widely used in power systems and industrial applications due to its excellent linearity and the fact that it is not limited by the size of the measured current. Specifically, the introduction of a magnetic core design into the traditional air-core toroidal current sensor and the integration of specific magnetic materials can improve the mutual inductance and signal strength of the current sensor. However, this approach also introduces higher parasitic capacitance, which will have an adverse effect on the performance of the current sensor, including reducing the resonant frequency, reducing the measurement bandwidth, and causing phase errors and amplitude distortion at high frequencies, making the current measurement inaccurate, thereby affecting the control accuracy and stability of the power system, and severely limiting the application of magnetic core current sensors in high-frequency situations.

[0003] For broadband applications requiring a stable frequency response, the use of low-permeability core materials can maintain consistent permeability across the entire operating frequency range. Therefore, reliably determining the equivalent lumped parasitic capacitance of these frequency-stable, low-permeability core current sensors is crucial to maximizing their potential in broadband applications. To this end, there are currently two main methods for calculating the equivalent lumped parasitic capacitance of toroidal current sensors. The first method is the finite element simulation method, but this method requires a large amount of computing resources and has low computational efficiency. Furthermore, it essentially operates as a black box, making it difficult to clearly demonstrate electromagnetic principles and lacking interpretability, making it difficult for technicians to apply it in practice. The second method is the traditional analytical method, but this method generally assumes a uniform electric field distribution and ignores the nonlinear effects of core material properties and geometric factors on the electric field distribution. This results in large errors in determining the equivalent lumped parasitic capacitance. This error is difficult to accept in high-precision measurement applications and is likely to lead to system design failure or significant performance degradation.

[0004] Therefore, how to provide a more effective technical solution to determine the equivalent lumped parasitic capacitance of a low-permeability magnetic core current sensor is an urgent problem to be solved. Summary of the Invention

[0005] In view of this, the present invention provides a method and device for determining the equivalent lumped parasitic capacitance of a magnetic core current sensor. In the process of determining the target equivalent lumped parasitic capacitance, the unrestricted electric field coupling effect is taken into account, so that the determination accuracy of the target equivalent lumped parasitic capacitance is higher, which is beneficial to the design optimization of the magnetic core current sensor.

[0006] To solve the above technical problems, the present application provides a method for determining the equivalent lumped parasitic capacitance of a magnetic core current sensor, comprising:

[0007] Determine the design parameters of the magnetic core current sensor;

[0008] determining an electric field distribution of the magnetic core current sensor at this time based on the design parameters, so as to establish a distributed parasitic capacitance network of the magnetic core current sensor based on the electric field distribution; wherein the electric field distribution is related to a dielectric constant of the magnetic core material included in the design parameters;

[0009] Obtaining a target correction factor for characterizing the nonlinear electric field coupling effect according to a strategy for determining the inter-turn distance, the turn-to-core distance, and a preset correction factor included in the design parameters;

[0010] The capacitance value of the inter-turn capacitance of each winding head and end included in the distributed parasitic capacitance network is determined according to the target correction factor and the design parameters, so as to obtain the target equivalent lumped parasitic capacitance under the design parameters according to the capacitance value of the inter-turn capacitance of each winding head and end and the preset distributed parasitic network equivalent strategy.

[0011] Furthermore, after determining the design parameters of the magnetic core current sensor, the following steps are also included:

[0012] The magnetic core current sensor is divided into an inner region, an outer region and a parallel region according to its structure;

[0013] Determining the capacitance value of the first and last turn-to-turn capacitances of each winding included in the distributed parasitic capacitance network according to the target correction factor and the design parameters includes:

[0014] For the inter-turn capacitance between the first and last turns of each winding in the distributed parasitic capacitance network, perform the following steps:

[0015] Determine the basic capacitance per unit length of the winding head-end inter-turn capacitance in the target area according to a traditional analytical method, wherein the target areas are the inner area, the outer area, and the parallel area;

[0016] For the target area, the product of the basic capacitance value per unit length and the target correction factor under the target area is determined as the corrected capacitance value per unit length, so as to determine the capacitance value of the inter-turn capacitance between the beginning and end of the winding according to the corrected capacitance value per unit length under the target area.

[0017] Furthermore, the basic capacitance per unit length of the winding head-end turn-to-turn capacitance in the target area is determined according to a traditional analytical method, including:

[0018] The basic capacitance per unit length of the winding head-end turn-to-turn capacitance in the target area is determined according to a first preset relationship; the first preset relationship is:

[0019]

[0020] Among them, dC he represents the basic capacitance per unit length of the winding head-end inter-turn capacitance in the target area, ε0 is the vacuum dielectric constant, d tt is the turn-to-turn distance included in the design parameters, d c is the winding diameter included in the design parameters, α is the integral angle determined according to the winding geometry setting corresponding to the inter-turn capacitance between the first and last turns of the winding and the electric field distribution, ε e is the regional equivalent dielectric constant determined based on the second preset relationship;

[0021] The second preset relationship is:

[0022]

[0023] Among them, d all is the thickness of the target area, is the thickness of the i-th medium included under the target area, is the dielectric constant of the i-th medium included in the target area.

[0024] Furthermore, after obtaining the target equivalent lumped parasitic capacitance under the design parameters according to the capacitance values ​​of the inter-turn capacitances at the beginning and end of each winding and the preset distributed parasitic network equivalent strategy, the method further includes:

[0025] Determining a key performance parameter corresponding to the magnetic core current sensor and used to evaluate high-frequency characteristics according to the target equivalent lumped parasitic capacitance;

[0026] A result of determining whether the current design parameters meet target performance requirements is determined based on the key performance parameters.

[0027] Furthermore, the target equivalent lumped parasitic capacitance under the design parameters is obtained according to the capacitance values ​​of the inter-turn capacitances at the beginning and end of each winding and the preset distributed parasitic network equivalent strategy, including:

[0028] Determining a summed average value of capacitance values ​​of each turn-to-turn capacitance in the distributed parasitic capacitance network;

[0029] Calculation is performed according to a third preset relationship to determine the target equivalent lumped parasitic capacitance of the magnetic core current sensor under the design parameters; the third preset relationship is:

[0030]

[0031] Where, EPC represents the capacitance value of the target equivalent lumped parasitic capacitance, C tt represents the summed average value, N is the total number of turns of the winding of the magnetic core current sensor, d represents the number of turns in the area where the electric field lines in the head turn flow directly to the tail turn in the shortest distance determined according to the electric field distribution, k is the turn number and C hek Indicates the capacitance value of the inter-turn capacitance of the kth winding, C csk represents the capacitance value of the kth series equivalent capacitor of the winding in a non-sector-shaped area determined according to the distributed parasitic network, where the non-sector-shaped area is obtained by dividing the structure of the magnetic core current sensor according to the electric field distribution.

[0032] Furthermore, a target correction factor for characterizing the nonlinear electric field coupling effect is obtained according to the turn-to-turn distance, the turn-to-core distance, and the preset correction factor determination strategy included in the design parameters, including:

[0033] For the target area, determining a target correction factor for characterizing the nonlinear electric field coupling effect according to the inter-turn distance, the turn-to-core distance included in the design parameters, and a correction factor characteristic expression determined in advance by fitting and corresponding to the target area;

[0034] The characteristic expression of the correction factor corresponding to the target area is:

[0035]

[0036] in, represents the target correction factor, d tt Denotes the inter-turn distance included in the design parameters, d tc represents the distance between the turns and the core included in the design parameters, b1 represents the first preset fitting coefficient corresponding to the target area, b2 represents the second preset fitting coefficient corresponding to the target area, b3 represents the third preset fitting coefficient corresponding to the target area, b4 represents the fourth preset fitting coefficient corresponding to the target area, b5 represents the fifth preset fitting coefficient corresponding to the target area, and b6 represents the sixth preset fitting coefficient corresponding to the target area.

[0037] Furthermore, the step of fitting and determining the characteristic expression of the correction factor corresponding to the target area in advance includes:

[0038] Acquiring simulation parameters, the simulation parameters including basic design parameters and M different parameter combinations, each of the parameter combinations including a turn-to-turn distance selected within a first preset geometric parameter range, a turn-to-core distance selected within a second preset geometric parameter range, and a dielectric constant of a core material; M being an integer greater than 1;

[0039] Determining, based on the simulation parameters, an actual correction factor corresponding to the target area under each parameter combination;

[0040] Selecting an undetermined quadratic polynomial expression, performing parameter fitting on actual correction factors corresponding to respective parameter combinations in the target area, to determine fitting coefficients in the undetermined quadratic polynomial expression in the target area, and then determining a characteristic expression of the undetermined correction factor corresponding to the target area based on the fitting coefficients;

[0041] An error analysis is performed based on the undetermined correction factor characteristic expression corresponding to the target area until the preset accuracy requirement is met, and it is determined that the undetermined correction factor characteristic expression under the target area is the correction factor characteristic expression determined by fitting.

[0042] Furthermore, determining the actual correction factor corresponding to the target area under each parameter combination based on the simulation parameters includes:

[0043] Performing a parameterized electromagnetic field simulation on the target area based on the simulation parameters to obtain the electric field distribution corresponding to each parameter combination, and the simulated capacitance value of the inter-turn capacitance of each winding head and end in the target area;

[0044] Determine the theoretical capacitance value of the first and last turn-to-turn capacitances of each winding in the target area under each parameter combination according to the electric field distribution and a traditional analytical method;

[0045] For each parameter combination, the actual correction factor corresponding to the first and last turn-to-turn capacitance of each winding in the target area is determined to be the ratio of the simulated capacitance value to the theoretical capacitance value.

[0046] Furthermore, an undetermined quadratic polynomial expression is selected, and parameter fitting is performed for the actual correction factors corresponding to each parameter combination in the target area, including:

[0047] An undetermined quadratic polynomial expression is selected, and parameter fitting is performed using the least squares method for actual correction factors corresponding to each parameter combination in the target area.

[0048] To solve the above technical problems, the present invention further provides a device for determining the equivalent lumped parasitic capacitance of a magnetic core current sensor, comprising:

[0049] memory for storing computer programs;

[0050] The processor is configured to implement the steps of the method for determining the equivalent lumped parasitic capacitance of the magnetic core current sensor as described above when executing the computer program.

[0051] The present application provides a method and device for determining the equivalent lumped parasitic capacitance of a magnetic core current sensor, which includes determining the design parameters of the magnetic core current sensor; determining the electric field distribution of the magnetic core current sensor at this time based on the design parameters, so as to establish a distributed parasitic capacitance network of the magnetic core current sensor based on the electric field distribution; the electric field distribution is related to the dielectric constant of the magnetic core material included in the design parameters; determining a strategy based on the turn-to-turn distance, the turn-to-core distance and a preset correction factor included in the design parameters to obtain a target correction factor for characterizing the nonlinear electric field coupling effect; determining the capacitance value of the inter-turn capacitance of each winding at the beginning and end of the distributed parasitic capacitance network based on the target correction factor and the design parameters, so as to obtain the target equivalent lumped parasitic capacitance under the design parameters based on the capacitance value of the inter-turn capacitance of each winding at the beginning and end and the preset distributed parasitic network equivalent strategy. It can be seen that in this scheme, the dielectric constant of the core material, the distance between turns, and the distance between turns and the core are taken into account in the process of determining the target equivalent lumped parasitic capacitance, and then the target correction factor for characterizing the nonlinear electric field coupling effect is determined, so that the determination accuracy of the target equivalent lumped parasitic capacitance is higher, which is conducive to improving calculation efficiency. It can also adapt to the determination of the target equivalent lumped parasitic capacitance of the core current sensor under the design parameters of various geometric sizes and core materials, which is beneficial for subsequent technicians to accurately determine the performance of the core current sensor under the current design parameters and is conducive to the design optimization of the core current sensor.

[0052] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0054] Figure 1 A flow chart of a method for determining the equivalent lumped parasitic capacitance of a magnetic core current sensor provided by the present invention;

[0055] Figure 2 A schematic structural diagram of a magnetic core current sensor provided by the present invention;

[0056] Figure 3 A schematic diagram of a structure for dividing a magnetic core current sensor into regions according to electric field distribution provided by the present invention;

[0057] Figure 4 A schematic structural diagram of a distributed parasitic capacitance network provided by the present invention;

[0058] Figure 5 A schematic diagram of a magnetic core current sensor provided by the present invention is divided into an inner area, an outer area and a parallel area;

[0059] Figure 6 A schematic diagram of the winding geometric structure setting corresponding to the inter-turn capacitance at the beginning and end of the winding provided by the present invention;

[0060] Figure 7 A schematic structural diagram of a device for determining the equivalent lumped parasitic capacitance of a magnetic core current sensor provided by the present invention. DETAILED DESCRIPTION

[0061] The core of the present invention is to provide a method and device for determining the equivalent lumped parasitic capacitance of a magnetic core current sensor. In the process of determining the target equivalent lumped parasitic capacitance, the unrestricted electric field coupling effect is taken into account, so that the determination accuracy of the target equivalent lumped parasitic capacitance is higher, which is beneficial to the design optimization of the magnetic core current sensor.

[0062] The following will be combined with the accompanying drawings in the embodiments of the present application to clearly describe the technical solutions in the embodiments of the present application. Obviously, the embodiments described are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of this application.

[0063] The terms "first," "second," and the like in the specification and claims of this application are used to distinguish similar objects, and are not used to describe a specific order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, so that the embodiments of this application can be implemented in an order other than that illustrated or described herein, and that the objects distinguished by "first," "second," and the like are generally of the same type, and do not limit the number of objects; for example, the first object can be one or more. In addition, the term "and / or" in the specification and claims refers to at least one of the connected objects, and the character " / " generally indicates that the objects connected are in an "or" relationship.

[0064] Please refer to Figure 1 , Figure 1 The present invention provides a flow chart of a method for determining the equivalent lumped parasitic capacitance of a magnetic core current sensor.

[0065] The method for determining the equivalent lumped parasitic capacitance of the magnetic core current sensor includes:

[0066] S11: Determine design parameters of the magnetic core current sensor;

[0067] S12: determining an electric field distribution of the magnetic core current sensor at this time based on the design parameters, so as to establish a distributed parasitic capacitance network of the magnetic core current sensor based on the electric field distribution; the electric field distribution is related to a dielectric constant of the magnetic core material included in the design parameters;

[0068] S13: obtaining a target correction factor for characterizing the nonlinear electric field coupling effect according to a strategy for determining the turn-to-turn distance, the turn-to-core distance, and a preset correction factor included in the design parameters;

[0069] S14: Determine the capacitance value of the head-end turn-to-turn capacitance of each winding included in the distributed parasitic capacitance network according to the target correction factor and the design parameters, so as to obtain the target equivalent lumped parasitic capacitance under the design parameters according to the capacitance value of the head-end turn-to-turn capacitance of each winding and the preset distributed parasitic network equivalent strategy.

[0070] In this embodiment, it is taken into account that the parasitic capacitance not only affects the bandwidth of the magnetic core current sensor, but also leads to an increase in measurement error, a decrease in signal-to-noise ratio, and a decrease in temperature stability. Especially in dynamic measurement and transient monitoring applications, the resonance phenomenon caused by the parasitic capacitance will seriously affect the reliability of the measurement results; in addition, in emerging application scenarios such as electric vehicles and smart grids, there are also strict requirements on the volume and weight of the magnetic core current sensor, which requires the sensor to minimize the influence of parasitic capacitance while maintaining high performance. To this end, the present application provides a method for determining the equivalent lumped parasitic capacitance of a magnetic core current sensor. By considering the comprehensive influence of material properties and geometric factors (here referring to the distance between turns and the distance between turns and the core), a correction factor considering the nonlinear electric field coupling effect is introduced, which is conducive to the accurate determination of the equivalent lumped parasitic capacitance of the magnetic core current sensor, and also provides a basis for the design and optimization of high-performance magnetic core current sensors.

[0071] Specifically, the magnetic core current sensor here is essentially a toroidal current sensor with a magnetic core, more specifically a toroidal current sensor with low magnetic permeability and a magnetic core (the low magnetic permeability magnetic core referred to here can be a magnetic powder core or NiZn core, etc., which are made of materials with a magnetic permeability less than a preset threshold. In contrast, MnZn and nanocrystalline cores are high magnetic permeability magnetic cores). Please refer to Figure 2 , Figure 2 A schematic diagram of the structure of a magnetic core current sensor provided by the present invention is shown in FIG. Figure 2As shown, the winding 11 is wound around the magnetic core 12 to form a coil. This structure is a schematic diagram of the structure of the magnetic core current sensor. When the magnetic core current sensor is in use, the wire 13 to be measured with the current I1 passes through the center of the magnetic core current sensor, as shown in FIG. Figure 2 shown.

[0072] To elaborate, the design parameters in step S11 include basic design parameters, the dielectric constant of the core material, the distance between turns, and the distance between turns and the core; the basic design parameters here may include the wire specifications used for the winding (such as diameter), the total number of turns after the winding is wound, etc. The reason for considering the dielectric constant of the core material, the distance between turns, and the distance between turns and the core in determining the equivalent lumped parasitic capacitance is that, using Ansys Maxwell electromagnetic field simulation software, the electric field distribution under different core materials and geometric conditions (here referring to the distance between turns and the distance between turns and the core) is analyzed. This clearly reveals that the geometric conditions and the dielectric constant of the core material nonlinearly affect the electric field coupling within the low-permeability core current sensor. This is also the reason why traditional analytical methods in the relevant art fail to consider these factors, resulting in errors in determining the equivalent lumped parasitic capacitance (especially when the distance between turns and the core and the distance between turns are large). More specifically, when the distance between turns and the core changes, the electric field intensity distribution changes nonlinearly; when the distance between turns changes, the electric field intensity distribution also changes nonlinearly. Core materials with different dielectric constants exhibit different degrees of nonlinear electric field coupling effects. Therefore, based on the above analysis of the nonlinear electric field coupling phenomenon, it can be seen that considering the dielectric constant of the core material, the distance between turns, and the distance between turns and the core can help improve the accuracy of determining the equivalent lumped parasitic capacitance.

[0073] In step S12, the current electric field distribution can be determined based on the design parameters by using finite element analysis software such as Ansys Maxwell electromagnetic field simulation software (it should be noted that the time required for determining the electric field distribution using only finite element analysis software is relatively short, and is much shorter than the time required for determining the equivalent lumped parasitic capacitance by using finite element simulation methods in related technologies), so as to accurately determine the electric field distribution, and then establish a distributed parasitic capacitance network of the magnetic core current sensor based on the electric field distribution. It can be understood that the electric field distribution is affected by the dielectric constant of the magnetic core material. This influence is nonlinear and cannot be expressed analytically, but it can be reflected in the electric field distribution. Please refer to Figure 3 , Figure 3The present invention provides a structural schematic diagram of a magnetic core current sensor that divides regions according to electric field distribution. The electric field distribution reflects the distribution of electric field lines. The magnetic core current sensor can be divided into fan-shaped regions and non-fan-shaped regions according to the distribution of electric field lines. Different regions correspond to different capacitances, so it is divided into two regions. On this basis, the capacitance between the first and last turns of the winding refers to the capacitance between the kth head turn and the kth tail turn. The maximum value that k can take is not less than 2 and k is an integer. The maximum value that k can take is determined by the number of groups of head turns and tail turns included in the fan-shaped region, such as Figure 3 As shown, it includes three groups of head turns and tail turns, namely the first head turn 111-the first tail turn 112, the second head turn 113-the second tail turn 114, and the third head turn 115-the third tail turn 116. Therefore, the maximum value that k can take is 3; the maximum value that k can take also defines the number of capacitances between the head and tail turns of the winding included in the distributed parasitic capacitance network, please refer to Figure 4 , Figure 4 The present invention provides a structural schematic diagram of a distributed parasitic capacitance network, which includes inter-turn capacitance, inter-turn capacitance between the beginning and end of the winding, turn-to-core capacitance of the winding in the non-sector area, and static capacitance inside the core of the winding in the non-sector area. Figure 4 Take the maximum value of k as 2, which includes the capacitance between the first and last turns of the two windings, as an example. Figure 4 It should be noted that the dotted line separating the air and the magnetic core means that the medium corresponding to the upper half of the dotted line is air, and the medium corresponding to the lower half is the magnetic core. Figure 4 The first winding end turn capacitance C he1 And the second winding first and end turn capacitance C he2 , represents the inter-turn capacitance C between the first turn and the second turn 12 , represents the inter-turn capacitance C between the ath turn and the a+1th turn a,a+1 , represents the inter-turn capacitance C between the Na-1th turn and the Nath turn N-a-1,N-a (Here a represents the number of turns of the winding in the non-sector area, N represents the total number of turns of the winding of the magnetic core current sensor), represents the inter-turn capacitance C between the Nth turn and the N-1th turn. N,N-1 , the static capacitance C inside the core of the first winding in the non-sector area cs1 , the static capacitance C inside the core of the second winding in the non-sector area cs2 , represents the capacitance C from the winding turn to the core in the non-sector area a,c (It should be noted that the c here is only used to indicate that the capacitance falls in the non-sector area and does not have an actual label meaning), represents the turn-to-core capacitance C of the winding in the non-sector area N-a-1,c(The c here also has no actual label meaning) and represents the turn-to-core capacitance C of the winding in the non-sector area. N-a,c (The c here also has no actual label meaning).

[0074] Furthermore, based on the fact that the head-to-tail turn-to-turn capacitance of the winding plays a dominant role in the equivalent lumped parasitic capacitance in this distributed parasitic capacitance network, the target correction factor obtained in step 13 is used in step S14 to correct the head-to-tail turn-to-turn capacitance of each winding to obtain the corrected capacitance value of the head-to-tail turn-to-turn capacitance of each winding, and then the target equivalent lumped parasitic capacitance is determined based on this.

[0075] In summary, the present application provides a method for determining the equivalent lumped parasitic capacitance of a magnetic core current sensor. In the process of determining the target equivalent lumped capacitance, the scheme takes into account the nonlinear electric field coupling effect caused by the dielectric constant of the magnetic core material, the distance between turns, and the distance between turns and the core, and then determines the target correction factor for characterizing the nonlinear electric field coupling effect, so that the target equivalent lumped capacitance is determined with higher accuracy (especially under extreme geometric conditions, such as a large turn-to-core distance or turn-to-turn distance, high accuracy can still be maintained), which is conducive to improving calculation efficiency and can adapt to the determination of the target equivalent lumped capacitance of the magnetic core current sensor under design parameters of various geometric dimensions and magnetic core materials (i.e., different numbers of turns, different magnetic core materials, and different geometric dimensions, etc.), which is conducive to subsequent technicians accurately determining the performance of the magnetic core current sensor under the current design parameters, and is conducive to the design optimization of the magnetic core current sensor, and is conducive to improving the measurement accuracy of the magnetic core current sensor, expanding the bandwidth, and adapting to diverse application scenarios.

[0076] Based on the above embodiment:

[0077] In some embodiments, after determining the design parameters of the magnetic core current sensor, the method further includes:

[0078] The magnetic core current sensor is divided into inner area, outer area and parallel area according to its structure;

[0079] The capacitance values ​​of the turn-to-turn capacitances of each winding included in the distributed parasitic capacitance network are determined based on the target correction factor and design parameters, including:

[0080] For the inter-turn capacitance at the beginning and end of each winding in the distributed parasitic capacitance network, perform the following steps:

[0081] Determine the basic capacitance per unit length of the winding head-end inter-turn capacitance in the target area using the traditional analytical method. The target areas are the inner area, the outer area, and the parallel area.

[0082] For the target area, the product of the basic capacitance value per unit length and the target correction factor under the target area is determined as the corrected capacitance value per unit length, so as to determine the capacitance value of the inter-turn capacitance at the beginning and end of the winding according to the corrected capacitance value per unit length under the target area.

[0083] For details, please refer to Figure 5 , Figure 5 This is a schematic diagram of a magnetic core current sensor divided into an inner region, an outer region, and a parallel region. It should be noted that this division is due to the slightly different geometric structures of the three regions: the inner region is an inner arc surface, the outer region is an outer arc surface, and the parallel region is a flat surface. This has a certain impact on the electric field distribution, that is, the capacitance. More specifically, the parallel region is the upper and lower regions separated by half the height, and the outer region is the region outside the radial thickness. The inner region is the region within the radial thickness.

[0084] For the inter-turn capacitance of each winding at the beginning and end under the distributed parasitic capacitance network, the internal area, the external area and the parallel area are respectively taken as the target areas, and the basic capacitance per unit length of the inter-turn capacitance of the winding at the beginning and end in the target area is determined; and the target correction factor under the target area is used to correct it, that is, for the target area, the product of the basic capacitance per unit length and the target correction factor under the target area is determined as the corrected capacitance per unit length; since the length under the target area is a known number, the product of the corrected capacitance per unit length under the target area and the corresponding length is the corrected capacitance value under the target area, and the sum of the corrected capacitance values ​​under the target area is determined to be the capacitance value of the inter-turn capacitance of the winding at the beginning and end.

[0085] It can be seen that the above setting is conducive to the subsequent accurate determination of the target equivalent lumped parasitic capacitance.

[0086] In some embodiments, determining the basic capacitance per unit length of the winding head-end turn-to-turn capacitance in the target area according to a conventional analytical method includes:

[0087] The basic capacitance per unit length of the winding head-end inter-turn capacitance in the target area is determined according to a first preset relationship; the first preset relationship is:

[0088]

[0089] Among them, dC he It represents the basic capacitance per unit length of the winding head-end inter-turn capacitance in the target area, ε0 is the vacuum dielectric constant, d tt is the turn-to-turn distance included in the design parameters, d cis the winding diameter included in the design parameters, α is the integral angle determined according to the winding geometry setting corresponding to the inter-turn capacitance at the beginning and end of the winding and the electric field distribution, ε e is the regional equivalent dielectric constant determined based on the second preset relationship;

[0090] The second preset relationship is:

[0091]

[0092] Among them, d all is the thickness of the target area, is the thickness of the i-th medium included under the target area, is the dielectric constant of the i-th medium included in the target area.

[0093] For details, please refer to Figure 6 , Figure 6 The present invention provides a winding geometry configuration diagram corresponding to the capacitance between the first and last turns of the winding. In the diagram, any set of first turns and tail turns is taken as an example. tt and d c It is understandable that the medium included in the target area referred to here can be air and / or a magnetic core, which can be determined according to actual conditions.

[0094] In addition, it can be seen that the basic capacitance per unit length of the winding head-end inter-turn capacitance determined by the traditional analytical method in the target area only takes into account the winding diameter and the distance between the turns, while ignoring the influence of the distance between the turns and the core and the nonlinear electric field coupling effect, resulting in insufficient accuracy in determining the target equivalent lumped parasitic capacitance. The correction factor set in this application can make up for this deficiency to improve the accuracy of determining the target equivalent lumped parasitic capacitance. In some embodiments, after obtaining the target equivalent lumped parasitic capacitance under the design parameters based on the capacitance value of the inter-turn capacitance of each winding head and the preset distributed parasitic network equivalent strategy, it also includes:

[0095] Determine the key performance parameters of the magnetic core current sensor for evaluating high-frequency characteristics based on the target equivalent lumped parasitic capacitance;

[0096] The result of determining whether the current design parameters meet the target performance requirements based on key performance parameters.

[0097] Specifically, the key performance parameters here may include resonant frequency and bandwidth, etc., which are not particularly limited here; the target performance requirements are set in advance for the magnetic core current sensor, so it is possible to determine whether the current design parameters meet the target performance requirements based on the key performance parameters. If not, the design parameters can be readjusted and the target equivalent lumped parasitic capacitance can be recalculated until the design parameters that meet the target performance requirements are obtained.

[0098] It is understandable that the designed magnetic core current sensor can be applied to various scenarios requiring accurate current measurement, such as power systems, industrial automation, smart grids, power electronic equipment, etc., without any special limitation here. It can be seen that the settings in this application are convenient for engineering and technical personnel to apply in actual design, significantly improving the efficiency and accuracy of the design of low-permeability magnetic core current sensors, and helping technicians to predict the high-frequency performance of the current sensor based on design parameters before manufacturing the magnetic core current sensor, reducing trial and error costs and development cycles, and improving development efficiency.

[0099] In some embodiments, the target equivalent lumped parasitic capacitance under design parameters is obtained based on the capacitance values ​​of the turn-to-turn capacitances at the beginning and end of each winding and a preset distributed parasitic network equivalent strategy, including:

[0100] Determine the summed average value of the capacitance values ​​of each turn-to-turn capacitance in the distributed parasitic capacitance network;

[0101] The target equivalent lumped parasitic capacitance of the magnetic core current sensor under the design parameters is determined by calculation according to the third preset relationship; the third preset relationship is:

[0102]

[0103] Where EPC represents the capacitance value of the target equivalent lumped parasitic capacitance, C tt represents the summed average value, N is the total number of turns of the winding of the magnetic core current sensor, d represents the number of turns in the area where the electric field lines in the first turn flow directly to the tail turn in the shortest distance determined by the electric field distribution, k is the turn number and C hek Indicates the capacitance value of the inter-turn capacitance of the kth winding, C csk It represents the capacitance value of the kth series equivalent capacitor of the winding in the non-sector area determined according to the distributed parasitic network. The non-sector area is obtained by dividing the structure of the magnetic core current sensor according to the electric field distribution.

[0104] Specifically, the fan-shaped area and the non-fan-shaped area described here have been described in detail in the aforementioned embodiment and will not be described here in detail. It should also be noted that the winding of the winding on the magnetic core in the magnetic core current sensor here can be wound partially (more than half the core) or completely uniformly, and d represents the number of turns in the area where the electric field lines in the first turn flow directly to the tail turn at the shortest distance, determined according to the electric field distribution. In addition, corresponding to Figure 4 The series equivalent capacitance may include a first series equivalent capacitance and a second series equivalent capacitance. The first series equivalent capacitance is represented by the turn of the winding in the non-sector area to the core capacitance C a,c , the static capacitance C inside the core of the first winding in the non-sector area cs1, represents the capacitance C from the winding turn to the core in the non-sector area N-a,c The capacitance of the first series equivalent capacitor is obtained as follows: 1 / (1 / the static capacitance C inside the magnetic core of the first winding in the non-sector area) cs1 The capacitance value + 1 / represents the capacitance C from the winding turn to the core in the non-sector area. a,c The capacitance value + 1 / represents the capacitance C from the winding turn to the core in the non-sector area. N-a,c Similarly, the second series equivalent capacitance is represented by the turn to core capacitance C in the non-sector region of the winding. a,c , the static capacitance C inside the core of the second winding in the non-sector area cs2 , represents the capacitance C from the winding turn to the core in the non-sector area N-a-1,c The capacitance of the second series equivalent capacitor is obtained as follows: 1 / (1 / the static capacitance C inside the magnetic core of the second winding in the non-sector area) cs2 The capacitance value + 1 / represents the capacitance C from the winding turn to the core in the non-sector area. a,c The capacitance value + 1 / represents the capacitance C from the winding turn to the core in the non-sector area. N-a-1,c capacitance value).

[0105] In some embodiments, a target correction factor for characterizing the nonlinear electric field coupling effect is obtained based on the turn-to-turn distance, the turn-to-core distance, and a preset correction factor determination strategy included in the design parameters, including:

[0106] For the target area, a target correction factor for characterizing the nonlinear electric field coupling effect is determined based on the inter-turn distance, the turn-to-core distance included in the design parameters, and a correction factor characteristic expression corresponding to the target area determined by pre-fitting;

[0107] The characteristic expression of the correction factor corresponding to the target area is:

[0108]

[0109] in, represents the target correction factor, d tt Denotes the turn-to-turn distance included in the design parameters, d tc represents the distance between the turns and the core included in the design parameters, b1 represents the first preset fitting coefficient corresponding to the target area, b2 represents the second preset fitting coefficient corresponding to the target area, b3 represents the third preset fitting coefficient corresponding to the target area, b4 represents the fourth preset fitting coefficient corresponding to the target area, b5 represents the fifth preset fitting coefficient corresponding to the target area, and b6 represents the sixth preset fitting coefficient corresponding to the target area.

[0110] It should be noted that the corresponding correction factor characteristic expressions are determined in advance for the internal area, the external area, and the parallel area respectively. The difference in the correction factor characteristic expressions of different areas lies in the difference in the six preset fitting coefficients b1 to b6.

[0111] In some embodiments, the step of pre-fitting and determining the characteristic expression of the correction factor corresponding to the target area includes:

[0112] Acquiring simulation parameters, where the simulation parameters include basic design parameters and M different parameter combinations, each parameter combination including a turn-to-turn distance selected within a first preset geometric parameter range, a turn-to-core distance selected within a second preset geometric parameter range, and a dielectric constant of the core material; M is an integer greater than 1;

[0113] Determine the actual correction factor corresponding to the target area under each parameter combination based on the simulation parameters;

[0114] Selecting an undetermined quadratic polynomial expression, performing parameter fitting on the actual correction factors corresponding to each parameter combination in the target area, to determine the fitting coefficients in the undetermined quadratic polynomial expression in the target area, and then determining the characteristic expression of the undetermined correction factor corresponding to the target area based on the fitting coefficients;

[0115] The error analysis is performed according to the characteristic expression of the undetermined correction factor corresponding to the target area until the preset accuracy requirement is met and the characteristic expression of the undetermined correction factor under the target area is determined to be the correction factor characteristic expression determined by fitting.

[0116] Specifically, the basic design parameters here may include the wire specifications (such as diameter) used for the winding, the total number of turns after the winding is wound, etc. In actual applications, the basic design parameters can remain unchanged, or multiple parameter combinations can be set. No special restrictions are made here, and they can be set flexibly; different parameter combinations can be obtained by selecting the turn-to-turn distance within the first preset geometric parameter range, the turn-to-core distance selected within the second preset geometric parameter range, and setting different dielectric constants of the core materials.

[0117] Since the magnetic core current sensor has been divided into an internal area, an external area and a parallel area according to its structure; the actual correction factor corresponding to the target area under each parameter combination is determined based on the simulation parameters (the target areas here are still the internal area, the external area and the parallel area respectively), and the characteristic expression of the pending correction factor corresponding to the target area is determined by parameter fitting; error analysis is performed based on the characteristic expression of the pending correction factor corresponding to the target area. If the error accuracy does not meet the preset accuracy requirements, the fitted pending quadratic polynomial expression and / or the fitting coefficient therein is adjusted, or the simulation parameters are increased (such as adding a few more sets of parameter combinations) until the error accuracy meets the preset accuracy requirements, and the correction factor characteristic expression under the target area obtained by fitting is determined.

[0118] In some embodiments, a quadratic polynomial expression to be determined is selected, and parameter fitting is performed for actual correction factors corresponding to each parameter combination in the target area, including:

[0119] Select the undetermined quadratic polynomial expression and use the least squares method to perform parameter fitting for the actual correction factors corresponding to each parameter combination in the target area. It is understandable that the optimization algorithm used for parameter fitting here can also be other algorithms and is not particularly limited here.

[0120] In some embodiments, determining the actual correction factor corresponding to the target area under each parameter combination based on the simulation parameters includes:

[0121] Perform parameterized electromagnetic field simulation on the target area based on the simulation parameters to obtain the corresponding electric field distribution under each parameter combination, as well as the simulated capacitance value of the inter-turn capacitance at the beginning and end of each winding in the target area;

[0122] Determine the theoretical capacitance value of the turn-to-turn capacitance of each winding in the target area under each parameter combination based on the electric field distribution and traditional analytical methods;

[0123] For each parameter combination, the actual correction factor corresponding to the capacitance between the first and last turns of each winding in the target area is determined as the ratio of the simulated capacitance value to the theoretical capacitance value.

[0124] Specifically, based on the simulation parameters, Ansys Maxwell electromagnetic field simulation software can be used to perform parameterized electromagnetic field simulation on the target area to obtain the corresponding electric field distribution under each parameter combination and the simulated capacitance value of each winding's head-end interturn capacitance in the target area. Based on the electric field distribution, a corresponding distributed parasitic capacitance network can be established to obtain the theoretical capacitance value of each winding's head-end interturn capacitance in the target area under each parameter combination. Then, for each parameter combination, the actual correction factor corresponding to each winding's head-end interturn capacitance in the target area is determined as the ratio of the simulated capacitance value to the theoretical capacitance value. Subsequently, an undetermined quadratic polynomial expression is selected, and from the perspective of the target area, all actual correction factors in the target area are used as a data set for parameter fitting.

[0125] Furthermore, error analysis is performed based on the characteristic expression of the pending correction factor corresponding to the target area to determine the error accuracy, including but not limited to: for the target area, determining the target correction factor based on the current parameter combination and the characteristic expression of the pending correction factor, and then determining the corrected capacitance value of the capacitance between the first and last turns of each winding in the target area based on the target correction factor and the theoretical capacitance value, and performing error analysis based on the corrected capacitance value and the corresponding simulated capacitance value to determine the error accuracy.

[0126] It can be seen that the above method can accurately and reliably establish the characteristic expression of the correction factor in the internal area, external area, and parallel area, and then directly call it on demand. This method of using analytical expressions is conducive to quickly obtaining the target equivalent lumped parasitic capacitance. Compared with the finite element simulation method in the current related technology, it has higher computational efficiency and is convenient for engineering application and design optimization.

[0127] Furthermore, as a demonstration of the effectiveness of the target equivalent lumped parasitic capacitance determination method of the magnetic core current sensor provided in this application, low-permeability magnetic core current sensors with NiZn material cores and magnetic powder cores were selected respectively, and the geometric parameters of the low-permeability magnetic core current sensor with NiZn material cores were set to an outer diameter of 50 mm, an inner diameter of 30 mm, and a height of 20 mm; the geometric parameters of the low-permeability magnetic core current sensor with magnetic powder cores were set to an outer diameter of 47.63 mm, an inner diameter of 23.32 mm, and a height of 18.92 mm. By controlling the geometric parameters and the number of turns, coils under different conditions were constructed, the test frequency range was set to 20 kHz to 30 MHz, and the test used an impedance analyzer and determined the actual measured capacitance value by fitting the impedance curve obtained.

[0128] The test results of the low permeability core current sensor for NiZn material core are as follows:

[0129] For a low-permeability core current sensor with a 36-turn NiZn material core, when the distance between the turn and the core is 0.1 mm, the actual measured capacitance is 3.3 pF. The target equivalent lumped parasitic capacitance obtained by the solution provided in this application is 3.32 pF (the prediction error is 0.61%), and the equivalent lumped parasitic capacitance obtained by the traditional analytical method is 1.88 pF (the prediction error is 43.03%). When the distance between the turn and the core is 0.5 mm, the actual measured capacitance is 2.1 pF. The solution provided in this application obtains The target equivalent lumped parasitic capacitance value is 2.01pF (prediction error is 4.29%), and the equivalent lumped parasitic capacitance value obtained by the traditional analytical method is 1.04pF (prediction error is 50.47%); when the distance between the turn and the core is 1mm, the actual measured capacitance value is 1.6pF, and the target equivalent lumped parasitic capacitance value obtained by the solution provided in this application is 1.64pF (prediction error is 2.5%), and the equivalent lumped parasitic capacitance value obtained by the traditional analytical method is 0.7pF (prediction error is 56.25%).

[0130] For the low permeability core current sensor with 72 turns of NiZn material core, when the distance between the turn and the core is 0.1mm, the actual measured capacitance value is 3.7pF, the target equivalent lumped parasitic capacitance value obtained by the solution provided in this application is 3.68pF (the prediction error is 0.54%), and the equivalent lumped parasitic capacitance value obtained by the traditional analytical method is 2.25pF (the prediction error is 39.19%); when the distance between the turn and the core is 0.5mm, the actual measured capacitance value is 2.8pF, and the target equivalent lumped parasitic capacitance value obtained by the solution provided in this application is 3.68pF (the prediction error is 0.54%). The target equivalent lumped parasitic capacitance value is 2.69pF (prediction error is 3.93%), and the equivalent lumped parasitic capacitance value obtained by the traditional analytical method is 1.49pF (prediction error is 46.79%); when the distance between the turn and the core is 1mm, the actual measured capacitance value is 2.4pF, and the target equivalent lumped parasitic capacitance value obtained by the solution provided in this application is 2.37pF (prediction error is 1.25%), and the equivalent lumped parasitic capacitance value obtained by the traditional analytical method is 1.15pF (prediction error is 52.08%).

[0131] The test results of the low permeability magnetic core current sensor for the magnetic powder core are as follows:

[0132] For a low permeability magnetic core current sensor with 36 turns of magnetic powder core, when the distance between the turns and the core is

[0133] =0.1mm, the actual measured capacitance value is 5.5pF, the target equivalent lumped parasitic capacitance value obtained by the solution provided in this application is 5.26pF (the prediction error is 4.36%), and the equivalent lumped parasitic capacitance value obtained by the traditional analytical method is 5.18pF (the prediction error is 5.82%); when the turn-to-core distance = 0.5mm, the actual measured capacitance value is 4.4pF, the target equivalent lumped parasitic capacitance value obtained by the solution provided in this application is 4.46pF (the prediction error is 1.36%), and the equivalent lumped parasitic capacitance value obtained by the traditional analytical method is 3.91pF (the prediction error is 11.14%); when the turn-to-core distance = 1mm, the actual measured capacitance value is 3pF, the target equivalent lumped parasitic capacitance value obtained by the solution provided in this application is 2.99pF (the prediction error is 0.33%), and the equivalent lumped parasitic capacitance value obtained by the traditional analytical method is 2.43pF (the prediction error is 19%).

[0134] For a low permeability magnetic core current sensor with 72 turns of magnetic powder core, when the distance between the turns and the core is

[0135] =0.1mm, the actual measured capacitance value is 9.2pF, the target equivalent lumped parasitic capacitance value obtained by the scheme provided in this application is 9.06pF (the prediction error is 1.52%), and the equivalent lumped parasitic capacitance value obtained by the traditional analytical method is 9pF (the prediction error is 2.17%); when the turn-to-core distance = 0.5mm, the actual measured capacitance value is 8.5pF, the target equivalent lumped parasitic capacitance value obtained by the scheme provided in this application is 8.52pF (the prediction error is 0.24%), and the equivalent lumped parasitic capacitance value obtained by the traditional analytical method is 7.77pF (the prediction error is 8.59%); when the turn-to-core distance = 1mm, the actual measured capacitance value is 7.6pF, the target equivalent lumped parasitic capacitance value obtained by the scheme provided in this application is 7.62pF (the prediction error is 0.26%), and the equivalent lumped parasitic capacitance value obtained by the traditional analytical method is 6.33pF (the prediction error is 16.71%).

[0136] It can be seen that for materials with lower dielectric constants (the dielectric constant of the magnetic powder core is 30, and the dielectric constant of the NiZn material core is 12), the error of the traditional analytical method increases significantly, and the technical solution provided in this application maintains high accuracy under all test conditions, with the maximum error not exceeding 4.36%, showing excellent stability and adaptability. Specifically, for the low magnetic permeability magnetic core current sensor with NiZn material core, the error range of the traditional analytical method is 39.19% to 56.25%, and the error range of the technical solution provided in this application is 0.54% to 4.29%. For the low magnetic permeability magnetic core current sensor with magnetic powder core, the error range of the traditional analytical method is 2.17% to 19%, and the error range of the technical solution provided in this application is 0.24% to 4.36%, which proves the effectiveness of the technical solution provided in this application in determining the equivalent lumped parasitic capacitance of the magnetic core current sensor, which is beneficial to practical applications.

[0137] Please refer to Figure 7 , Figure 7 A schematic structural diagram of a device for determining the equivalent lumped parasitic capacitance of a magnetic core current sensor provided by the present invention.

[0138] The device for determining the equivalent lumped parasitic capacitance of the magnetic core current sensor comprises:

[0139] Memory 31, for storing computer programs;

[0140] The processor 32 is configured to implement the steps of the method for determining the equivalent lumped parasitic capacitance of the magnetic core current sensor as described above when executing the computer program.

[0141] For an introduction to the device for determining the equivalent lumped parasitic capacitance of the magnetic core current sensor provided in this application, please refer to the embodiment of the method for determining the equivalent lumped parasitic capacitance of the magnetic core current sensor described above, which will not be repeated here.

[0142] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part description. Relational terms such as first and second are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of further restrictions, the elements limited by the sentence "comprising a" do not exclude the presence of other identical elements in the process, method, article or equipment including the elements.

[0143] The above description of the disclosed embodiments will enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is to be construed in the widest manner consistent with the principles and novel features disclosed herein.

Claims

1. A method for determining the equivalent lumped parasitic capacitance of a magnetic core current sensor, characterized in that: include: Determine the design parameters of the magnetic core current sensor; determining an electric field distribution of the magnetic core current sensor at this time based on the design parameters, so as to establish a distributed parasitic capacitance network of the magnetic core current sensor based on the electric field distribution; The electric field distribution is related to the dielectric constant of the magnetic core material included in the design parameters; Obtaining a target correction factor for characterizing the nonlinear electric field coupling effect according to a strategy for determining the inter-turn distance, the turn-to-core distance, and a preset correction factor included in the design parameters; The capacitance value of the inter-turn capacitance of each winding head and end included in the distributed parasitic capacitance network is determined according to the target correction factor and the design parameters, so as to obtain the target equivalent lumped parasitic capacitance under the design parameters according to the capacitance value of the inter-turn capacitance of each winding head and end and the preset distributed parasitic network equivalent strategy.

2. The method for determining the equivalent lumped parasitic capacitance of a magnetic core current sensor according to claim 1, wherein: After determining the design parameters of the magnetic core current sensor, it also includes: The magnetic core current sensor is divided into an inner region, an outer region and a parallel region according to its structure; Determining the capacitance value of the first and last turn-to-turn capacitances of each winding included in the distributed parasitic capacitance network according to the target correction factor and the design parameters includes: For the inter-turn capacitance between the first and last turns of each winding in the distributed parasitic capacitance network, perform the following steps: Determine the basic capacitance per unit length of the winding head-end inter-turn capacitance in the target area according to a traditional analytical method, wherein the target areas are the inner area, the outer area, and the parallel area; For the target area, the product of the basic capacitance value per unit length and the target correction factor under the target area is determined as the corrected capacitance value per unit length, so as to determine the capacitance value of the inter-turn capacitance between the beginning and end of the winding according to the corrected capacitance value per unit length under the target area.

3. The method for determining the equivalent lumped parasitic capacitance of a magnetic core current sensor according to claim 2, wherein: The basic capacitance per unit length of the winding head-end turn-to-turn capacitance in the target area is determined according to a traditional analytical method, including: The basic capacitance per unit length of the winding head-end turn-to-turn capacitance in the target area is determined according to a first preset relationship; the first preset relationship is: Among them, dC he represents the basic capacitance per unit length of the winding head-end inter-turn capacitance in the target area, ε0 is the vacuum dielectric constant, d tt is the turn-to-turn distance included in the design parameters, d c is the winding diameter included in the design parameters, α is the integral angle determined according to the winding geometry setting corresponding to the inter-turn capacitance between the first and last turns of the winding and the electric field distribution, ε e is the regional equivalent dielectric constant determined based on the second preset relationship; The second preset relationship is: Among them, d all is the thickness of the target area, is the thickness of the i-th medium included under the target area, is the dielectric constant of the i-th medium included in the target area.

4. The method for determining the equivalent lumped parasitic capacitance of a magnetic core current sensor according to claim 1, wherein: After obtaining the target equivalent lumped parasitic capacitance under the design parameters according to the capacitance values ​​of the inter-turn capacitances at the beginning and end of each winding and the preset distributed parasitic network equivalent strategy, the method further includes: Determining a key performance parameter corresponding to the magnetic core current sensor and used to evaluate high-frequency characteristics according to the target equivalent lumped parasitic capacitance; A result of determining whether the current design parameters meet target performance requirements is determined based on the key performance parameters.

5. The method for determining the equivalent lumped parasitic capacitance of a magnetic core current sensor according to claim 1, wherein: The target equivalent lumped parasitic capacitance under the design parameters is obtained according to the capacitance value of the inter-turn capacitance at the beginning and end of each winding and the preset distributed parasitic network equivalent strategy, including: Determining a summed average value of capacitance values ​​of each turn-to-turn capacitance in the distributed parasitic capacitance network; Calculation is performed according to a third preset relationship to determine the target equivalent lumped parasitic capacitance of the magnetic core current sensor under the design parameters; the third preset relationship is: Where, EPC represents the capacitance value of the target equivalent lumped parasitic capacitance, C tt represents the summed average value, N is the total number of turns of the winding of the magnetic core current sensor, d represents the number of turns in the area where the electric field lines in the head turn flow directly to the tail turn in the shortest distance determined according to the electric field distribution, k is the turn number and C hek Indicates the capacitance value of the inter-turn capacitance of the kth winding, C csk represents the capacitance value of the kth series equivalent capacitor of the winding in a non-sector-shaped area determined according to the distributed parasitic network, where the non-sector-shaped area is obtained by dividing the structure of the magnetic core current sensor according to the electric field distribution.

6. The method for determining the equivalent lumped parasitic capacitance of a magnetic core current sensor according to any one of claims 2 to 5, characterized in that: The target correction factor for characterizing the nonlinear electric field coupling effect is obtained according to the turn-to-turn distance, the turn-to-core distance, and the preset correction factor determination strategy included in the design parameters, including: For the target area, determining a target correction factor for characterizing the nonlinear electric field coupling effect according to the inter-turn distance, the turn-to-core distance included in the design parameters, and a correction factor characteristic expression determined in advance by fitting and corresponding to the target area; The characteristic expression of the correction factor corresponding to the target area is: in, represents the target correction factor, d tt Denotes the inter-turn distance included in the design parameters, d tc represents the distance between the turns and the core included in the design parameters, b1 represents the first preset fitting coefficient corresponding to the target area, b2 represents the second preset fitting coefficient corresponding to the target area, b3 represents the third preset fitting coefficient corresponding to the target area, b4 represents the fourth preset fitting coefficient corresponding to the target area, b5 represents the fifth preset fitting coefficient corresponding to the target area, and b6 represents the sixth preset fitting coefficient corresponding to the target area.

7. The method for determining the equivalent lumped parasitic capacitance of a magnetic core current sensor according to claim 6, wherein: The step of fitting and determining the characteristic expression of the correction factor corresponding to the target area in advance includes: Acquiring simulation parameters, the simulation parameters including basic design parameters and M different parameter combinations, each of the parameter combinations including a turn-to-turn distance selected within a first preset geometric parameter range, a turn-to-core distance selected within a second preset geometric parameter range, and a dielectric constant of a core material; M being an integer greater than 1; Determining, based on the simulation parameters, an actual correction factor corresponding to the target area under each parameter combination; Selecting an undetermined quadratic polynomial expression, performing parameter fitting on actual correction factors corresponding to respective parameter combinations in the target area, to determine fitting coefficients in the undetermined quadratic polynomial expression in the target area, and then determining a characteristic expression of the undetermined correction factor corresponding to the target area based on the fitting coefficients; An error analysis is performed based on the undetermined correction factor characteristic expression corresponding to the target area until the preset accuracy requirement is met, and it is determined that the undetermined correction factor characteristic expression under the target area is the correction factor characteristic expression determined by fitting.

8. The method for determining the equivalent lumped parasitic capacitance of a magnetic core current sensor according to claim 7, wherein: Determining, based on the simulation parameters, an actual correction factor corresponding to the target area under each parameter combination, includes: Performing a parameterized electromagnetic field simulation on the target area based on the simulation parameters to obtain the electric field distribution corresponding to each parameter combination, and the simulated capacitance value of the inter-turn capacitance of each winding head and end in the target area; Determine the theoretical capacitance value of the first and last turn-to-turn capacitances of each winding in the target area under each parameter combination according to the electric field distribution and a traditional analytical method; For each parameter combination, the actual correction factor corresponding to the first and last turn-to-turn capacitance of each winding in the target area is determined to be the ratio of the simulated capacitance value to the theoretical capacitance value.

9. The method for determining the equivalent lumped parasitic capacitance of a magnetic core current sensor according to claim 7, wherein: Selecting an undetermined quadratic polynomial expression, and performing parameter fitting for actual correction factors corresponding to each parameter combination in the target area, including: An undetermined quadratic polynomial expression is selected, and parameter fitting is performed using the least squares method for actual correction factors corresponding to each parameter combination in the target area.

10. A device for determining the equivalent lumped parasitic capacitance of a magnetic core current sensor, characterized in that: include: memory for storing computer programs; A processor, configured to implement the steps of the method for determining the equivalent lumped parasitic capacitance of the magnetic core current sensor according to any one of claims 1 to 9 when executing the computer program.

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