A method for calculating the frequency response characteristics of hollow winding coils of arbitrary shape

Abstract

The present invention discloses a method for quickly calculating the frequency response characteristics of a hollow winding coil of arbitrary shape, belonging to the technical field of electrical and electronic equipment components and sensors. The method comprises: establishing a three-dimensional rectangular reference coordinate system with a certain point in space as the origin; calculating the geometric center spatial coordinates of each turn based on the geometric centerline parameter equation of the skeleton, thereby obtaining the spatial parameter equation of each turn; combining the Newman formula to calculate the mutual inductance of any two turns and the self-inductance coefficient of the turns, the capacitance, resistance and skin depth between the turns, and the electrical relationship equation between any turn and other turns; writing the electrical relationship equation in matrix form, converting the coefficient matrix of the equation into an upper triangular matrix, and then converting the matrix into a coil port voltage and current relationship equation to obtain the coil port frequency response characteristics. The present invention has strong versatility, convenient calculation, and is easy to program for calculation, saving design time. No empirical formula is required during the calculation process, and the calculation accuracy is high.

Description

Technical Field

[0001] The present invention belongs to the field of designing a winding coil component with arbitrary shape in electrical and electronic equipment and measuring the winding coil sensor technology, and in particular relates to a fast calculation method for frequency response characteristics of a hollow winding coil with arbitrary shape. Background Art

[0002] Hollow-core coils are important and common components in electrical equipment. They block alternating current and can form tuned circuits with capacitors. They are also often used as sensors to measure the state of metal materials and eddy currents. They can also be used for energy transmission and to generate a desired electromagnetic environment. Hollow-core coils are the most common type of coil, and are divided into two types: flexible-frame coils and rigid-frame coils. The frequency response characteristics and electrical parameters of hollow-core coils affect the structure and device parameter matching of electrical equipment, as well as the performance of electrical equipment. The shape and size of the coil are affected by the installation space of the electrical equipment. The shape and size of the coil affect the internal parasitic parameters, which in turn affect the frequency response characteristics and electrical parameters of the coil. Therefore, the calculation methods of the frequency response characteristics and electrical parameters of hollow-core coils are important.

[0003] Currently, there are two common methods for calculating the frequency characteristics of air-core coils. One method uses electromagnetic simulation software to calculate the frequency characteristics and electrical parameters of air-core wound coils. However, since air-core coils often have a large number of turns (over a thousand), the turns are thin (no more than 0.1 mm), and the bobbin size and the airspace during simulation are often thousands of times larger than the wire diameter, it is difficult to use finite element electromagnetic simulation software to generate a three-dimensional mesh. Furthermore, randomly shaped coils are difficult to simulate in two dimensions using finite element electromagnetic simulation software. Numerical calculation methods based on theoretically derived formulas are only applicable to ideal cases, i.e., coils with specific shapes such as regular circles or flat spirals. They are not universally applicable to coils of arbitrary shapes. Therefore, there is currently no fast method for calculating the frequency characteristics and electrical parameters of air-core wound coils of arbitrary shapes, which poses significant challenges for designers and developers. Therefore, it is of great significance to develop a fast method for calculating the frequency response characteristics of air-core wound coils of arbitrary shapes. Summary of the Invention

[0004] In response to the above defects or improvement needs of the prior art, the present invention provides a method for quickly calculating the frequency response characteristics of hollow winding coils of arbitrary shapes, which has convenient calculation, high calculation accuracy and short calculation cycle.

[0005] To achieve the above objectives, according to one aspect of the present invention, a method for calculating the frequency response characteristics of an air-core wound coil of arbitrary shape is provided, comprising:

[0006] Taking any point near the hollow winding coil as the origin of the three-dimensional reference coordinate system, the spatial parametric equation of the geometric center line of the coil bobbin is obtained;

[0007] From the spatial parameter equation of the geometric center line of the coil skeleton, based on the distribution of the turns, the spatial coordinate equation of the geometric center of each turn of the coil is obtained;

[0008] According to the spatial coordinate equation of the geometric center of each coil turn, the spatial parameter equation of each coil turn is obtained;

[0009] According to the spatial parameter equation of each coil turn, the mutual inductance and capacitance between any two turns are obtained;

[0010] Calculate the self-inductance of any wire turn and the resistance taking into account the skin effect;

[0011] Based on the mutual inductance and capacitance between any two turns, as well as the self-inductance of any one turn and the resistance taking into account the skin effect, the voltage and current electrical relationship between each turn and the other turns is established, and the voltage and current electrical relationship between each turn and the other turns is combined and converted into a matrix equation form;

[0012] The coefficient matrix of the matrix equation is transformed into an upper triangular or lower triangular form, and the ratio of the port voltage and the port current is obtained according to the coefficient equation in the transformed upper triangular or lower triangular matrix form, thereby obtaining the port frequency characteristics of the coil.

[0013] In some optional embodiments, the spatial parameter equation of the geometric center line of the coil bobbin is used to obtain the spatial coordinate equation of the geometric center of each coil turn based on the distribution of the coil turns. This includes:

[0014] The spatial parameters of the geometric center line C of a hollow winding coil bobbin of arbitrary shape are (α(θ), β(θ), γ(θ)), where α(θ), β(θ), and γ(θ) are the parametric expressions of the center line C in the x, y, and z coordinates of the parametric equation. The projection of any point on the geometric center line on the rectangular coordinate system xOy is Q', and θ is the angle between the straight line between point Q' and the origin of the coordinate system and the positive direction of the rectangular coordinate x axis.

[0015] θ i and θ i+1 are the angles θ and θ corresponding to the i-th turn and the i+1-th turn respectively. i and θ i+1 The space is composed of several Δθ, and N is the total number of windings;

[0016] The coordinate expression of the geometric center of the i-th turn of the winding coil is: Where L is the length of the geometric center line, δ is a positive number that approaches zero infinitely, j represents the intermediate value of the calculation process, and J is the value that makes the coordinate expression of the geometric center of the i-th turn valid, that is, θ i+1 =θ i +JΔθ.

[0017] In some optional embodiments, the spatial parameter equation for each turn is:

[0018]

[0019] Among them, r is the radius of the circular cross section of the skeleton, t represents the intermediate parameter of the calculation process, each turn is divided into N1 parts, α′(θ i ),β′(θ i ),γ′(θ i ) are α(θ i ),β(θ i ),γ(θ i ) is the derivative of .

[0020] In some optional embodiments, the mutual inductance Mij between any two turns, the i-th turn and the j-th turn, is:

[0021]

[0022] F = (x′(i, g)) 2 +(y′(i, g)) 2 +(z′(i, g)) 2

[0023] H = (x′(j, h)) 2 +(y′(j,h)) 2 +(z′(j,h)) 2

[0024]

[0025] In which, each turn is divided into N1 equal parts, μ0 is the magnetic permeability of vacuum, (x′(i, t), y′(i, t), z′(i, t)) are the derivatives of (x(i, t), y(i, t), z(i, t)) with respect to t, and h and g represent the intermediate values ​​of the calculation process.

[0026] In some optional embodiments, the self-inductance L of any turn i is i for: Among them, r l is the radius of the winding.

[0027] In some optional implementations, the electrical relationship between the voltage and current of the ith turn and the other turns is: Among them, R i is the resistance of the ith turn considering the skin effect, I i is the branch current of the i-th turn, U i is the terminal voltage of the i-th turn, U N is the terminal voltage of the Nth turn, I S is the input current of the coil, ω=2πf, f is the frequency, C i , j is the capacitance between the ith and jth turns, C S is the parasitic capacitance of the impedance analyzer probe.

[0028] In some optional implementation schemes, the method of converting the voltage and current electrical relationship between the ith turn and other turns into a matrix form is:

[0029] and

[0030] in,

[0031]

[0032] Z i =(jωL i +R i )

[0033] In some optional embodiments, the method of converting the coefficient matrix of the matrix equation into upper triangular or lower triangular form is:

[0034] Will Transformed into and substitute Zhong Ke De

[0035] (A-ZB -1 C) into the form of an upper triangle, that is (A-ZB -1 C)=DE, E is an upper triangular matrix, and D and E are intermediate matrices generated during the calculation process.

[0036] In some optional embodiments, Get the ratio of port voltage and port current, F=D -1 ZB -1 .

[0037] In some optional embodiments, Get the frequency response characteristics of the coil or the ratio of the port voltage to the port current, where Z I (f), R(f) and L(f) are the frequency-dependent port input impedance, equivalent resistance and equivalent inductance of the coil, respectively.

[0038] According to another aspect of the present invention, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps of any one of the above methods are implemented.

[0039] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects compared with the prior art:

[0040] This invention provides a highly versatile method for rapidly calculating the frequency response characteristics of hollow-core coils of arbitrary shapes. The calculation is convenient, requiring no finite element or other simulation software. Programming is easy, saving design time. The calculation process requires no empirical formulas, resulting in high accuracy. Finally, the theoretical research is validated experimentally.

[0041] It can solve the following problems: 1. Existing common electromagnetic simulation software cannot perform grid calculations on coils with high-density fine windings; 2. Existing theoretical calculation methods are only applicable to winding coils with sparse wire turns on circular and square bobbins, and are not applicable to coils with high-density fine wire turns and arbitrary bobbin shapes.

[0042] The method for rapidly calculating coil frequency response characteristics proposed in this invention can quickly and accurately design coil sensors, inductors, and coupled inductors of arbitrary shapes. This solves the problem of the lack of a method for calculating the frequency response characteristics of coils of arbitrary shapes with fine windings, thereby reducing the difficulty of designers' work. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 Schematic diagram of a hollow winding coil with fine winding provided by an embodiment of the present invention;

[0044] Figure 2 is a schematic diagram of an equivalent circuit provided by an embodiment of the present invention;

[0045] Figure 3 This is a schematic diagram of an experiment provided by an embodiment of the present invention;

[0046] Figure 4 This is a comparison between an experimental result and a numerical calculation result provided by an embodiment of the present invention. (a) is Z I (ω) is the equivalent resistance R(f) of Z I The equivalent inductance L(f) of (ω) varies with frequency. DETAILED DESCRIPTION

[0047] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for the purpose of explaining the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0048] The present invention provides a method for quickly calculating the frequency response characteristics of a hollow winding coil of arbitrary shape, the method comprising the following steps:

[0049] Step 1: Set any point near the hollow winding coil as the origin of the three-dimensional reference coordinate system. If the coil is geometrically symmetrical, set the geometric center of the coil as the origin of the three-dimensional rectangular coordinate system, and the axis of symmetry of the coil's geometric center as the z-axis of the coordinate system.

[0050] Step 2: Based on the spatial parameter equation C of the geometric center line of the skeleton and the distribution of the turns, the spatial coordinate equation of the geometric center of each turn of the coil is obtained;

[0051] Step 3: Obtain the spatial parameter equation of each coil turn according to the spatial coordinate equation of the geometric center of each coil turn;

[0052] Step 4: Based on the spatial parameter equation of each coil turn, the mutual inductance and capacitance between any two turns are obtained;

[0053] Step 5: Obtain the self-inductance of any turn and the resistance considering the skin effect;

[0054] Step 6: Based on the mutual inductance and capacitance between any two turns, as well as the self-inductance of any one turn and the resistance taking into account the skin effect, establish the voltage and current electrical relationship between each turn and the other turns, and combine the voltage and current electrical relationship between each turn and the other turns into a matrix equation.

[0055] Step 7: Convert the coefficient matrix of the matrix equation into upper triangular or lower triangular form;

[0056] Step 8: According to the coefficient equation in the transformed upper triangular or lower triangular matrix form, the ratio of the port voltage to the port current is obtained, and then the port frequency characteristics of the coil are obtained.

[0057] Furthermore, the method for quickly calculating the spatial coordinates of the geometric center of the i-th coil turn in step 2 specifically includes:

[0058] The equation for the centerline C of a hollow winding coil bobbin of any shape is (α(θ), β(θ), γ(θ)). The projection of any point on the centerline C onto the rectangular coordinate system xOy is Q', and θ is the angle between the line between point Q' and the origin and the positive direction of the rectangular coordinate x-axis. i and θ i+1 are the angles θ corresponding to the i-th turn and the i+1-th turn respectively. i and θ i+1 The time is composed of several Δθ. Δθ is a number that tends to infinitesimal, and N is the total number of windings. The coordinate expression of the geometric center of the i-th turn of the winding coil is:

[0059]

[0060] In the above formula, L is the length of the center line C, and j represents the intermediate value of the calculation process. J is the value that makes the above formula valid, that is, θ i+1 =θ i +JΔθ.

[0061] Furthermore, the spatial parameter equation of each turn in step 3 is:

[0062]

[0063] Where r is the radius of the circular cross section of the skeleton, t represents the intermediate parameter of the calculation process, and each wire turn is divided into N1 equal parts.

[0064] Furthermore, a quick calculation method for the mutual inductance Mij between any two turns (the i-th turn and the j-th turn) in step 4 is:

[0065]

[0066] F = (x′(i, g)) 2 +(y′(i, g)) 2 +(z′(i, g)) 2

[0067] H=(x′(j,h)) 2 +(y′(j,h)) 2 +(z′(j,h)) 2

[0068]

[0069] where each turn is divided into N1 equal parts. μ0 is the magnetic permeability of vacuum. (x'(i, t), y'(i, t), z'(i, t)) are the derivatives of (x(i, t), y(i, t), z(i, t)) with respect to t. h and g represent intermediate values ​​during the calculation.

[0070] Furthermore, the self-inductance L of any turn i in step 5 is i A quick calculation method for:

[0071]

[0072] Among them, r l is the radius of the winding.

[0073] Furthermore, in step 6, the electrical relationship between the voltage and current of the i-th turn and the other turns is:

[0074]

[0075] Among them, R i is the resistance of the ith turn considering the skin effect. i is the branch current of the i-th turn, U i is the terminal voltage of the i-th turn, I S is the input current of the coil, ω=2πf, f is the frequency. i , j is the capacitance between the i-th turn and the j-th turn. C S is the parasitic capacitance of the impedance analyzer probe.

[0076] Furthermore, the voltage and current electrical relationship between the i-th turn and other turns is transformed into a matrix form:

[0077] and

[0078] in,

[0079]

[0080] Z i =(jωL i +R i )

[0081] Furthermore, in step 7, the method for converting the coefficient matrix of the matrix equation obtained in step 6 into an upper triangular or lower triangular form is:

[0082] First, replace step 6 with

[0083]

[0084] Transformed into

[0085]

[0086] Bring it in

[0087] Zhong Ke De

[0088] (A-ZB -1 C) is converted into an upper triangular form through MATLAB calculation, that is, (A-ZB -1 C)=DE, E is an upper triangular matrix, and D and E are intermediate matrices generated during the calculation process.

[0089] Furthermore, in step 8, the steps for obtaining the ratio of the port voltage to the port current according to the upper triangular coefficient matrix obtained in step 7 are as follows:

[0090]

[0091] The frequency response characteristics of the coil or the ratio of the terminal voltage to the terminal current is:

[0092]

[0093] Among them, Z I (f), R(f) and L(f) are the frequency-dependent port input impedance, equivalent resistance and equivalent inductance of the coil, respectively.

[0094] The embodiment of the present invention uses a common coil with a thin-wound circular frame and a circular cross-section for illustration.

[0095] like Figure 1 As shown, the embodiment has a hollow winding coil with a circular skeleton, 1600 turns, the diameter of the enameled wire winding is 0.14 mm, the skeleton cross-sectional radius is 4.2 mm, and the circular skeleton centerline diameter D is 127 mm.

[0096] Step 1: The geometric center of the coil is set as the origin of the three-dimensional rectangular coordinate system, and the geometric symmetry axis of the coil is the z-axis of the coordinate system;

[0097] Step 2. The equation of the skeleton centerline C is (0.5Dcos(θ), 0.5Dsin(θ), 0). The length L of the centerline C is πD, N is 1600 turns, and the projection of any point on the centerline C on the rectangular coordinate system xOy is Q'. θ is the angle between the line between point Q' and the origin and the positive direction of the rectangular coordinate x-axis. θ i and θ i+1 are the angles θ corresponding to the i-th turn and the i+1-th turn respectively. i and θ i+1 The space is composed of several Δθ. Δθ is a number that tends to infinitesimal, and N is the number of turns. The geometric center of the i-th turn of the winding coil can be calculated using the following coordinate expression in MATLAB:

[0098]

[0099] In the above formula, J is the value that makes the above formula valid, that is, θ i+1 =θ i +JΔθ.

[0100] Step 3: The spatial parameter equation of each turn is:

[0101]

[0102] The radius r of the circular cross section of the skeleton is 4.2 mm.

[0103] Step 4: The quick calculation methods for the mutual inductance Mij between any two turns (the i-th turn and the j-th turn) are:

[0104]

[0105] F=(x′(i,g)) 2 +(y′(i, g))+(z′(i, g)) 2

[0106] H=(x′(j,h)) 2 +(y′(j,h)) 2 +(z′(j,h)) 2

[0107]

[0108] where each turn is divided into N1 equal parts. μ0 is the permeability of vacuum. (x′(i, t), y′(i, t), z′(i, t)) are the derivatives of (x(i, t), y(i, t), z(i, t)) with respect to t.

[0109] Step 5: The self-inductance L of any turn i i A quick calculation method for:

[0110]

[0111] Where r is the radius of the winding l 0.7mm.

[0112] Step 6: Figure 2 The figure shows the coupling relationship between each wire turn. The electrical relationship between the voltage and current of any wire turn i and other wire turns is:

[0113]

[0114] Among them, R i is the resistance of the i-th wire turn considering the skin effect. i is the branch current of the i-th turn, U i is the terminal voltage of the i-th turn, IS is the input current of the coil, ω=2πf, f is the frequency. i,j is the capacitance between the i-th turn and the j-th turn. C S is the parasitic capacitance of the impedance analyzer probe.

[0115] Convert the voltage and current electrical relationship between the i-th turn and other turns into a matrix form:

[0116] and

[0117] in,

[0118]

[0119] Z i =(jωL i +R i )

[0120] Step 7: The method to convert the coefficient matrix of the matrix equation obtained in step 6 into upper triangular or lower triangular form is:

[0121] First, replace step 6 with

[0122]

[0123] Transformed into

[0124]

[0125] Changes bring it into

[0126] Zhong Ke De

[0127] (A-ZB -1 C) is converted into an upper triangular form through MATLAB calculation, that is, (A-ZB -1 C)=DE, E is an upper triangular matrix.

[0128] Step 8: Based on the coefficient equation in the upper triangular matrix form obtained in step 7, the steps to obtain the ratio of port voltage to port current are:

[0129]

[0130] The coil's port frequency response characteristics or the ratio of port voltage to port current are:

[0131]

[0132] Among them, Z I(f), R(f) and L(f) are the frequency-dependent port input impedance, equivalent resistance and equivalent inductance of the coil, respectively.

[0133] Among them, Z I (ω) is the port input voltage V at different frequencies N The ratio of Z to the current. I (ω) remains unchanged. As the frequency increases, Z is affected by the parasitic capacitance, inductance parameters and port parallel impedance of the coil. I The method for calculating the port frequency response characteristics proposed in the present invention provides a convenient method for designing coils of various shapes quickly, thereby reducing the difficulty of engineers' work.

[0134] like Figure 3 As shown, an impedance analyzer with a maximum frequency of 2 MHz is used to test the port frequency characteristics of the coil. Figure 4 (a) shows Z I The equivalent resistance R(f) of (ω) varies with frequency, Figure 4 (b) shows Z I The equivalent inductance L(f) of (ω) varies with frequency, Figure 4 The experimental results shown are consistent with the theoretical calculation results. The experimental results verify the correctness of the theoretical research.

[0135] Example 3

[0136] The present application also provides a computer-readable storage medium, such as a flash memory, a hard disk, a multimedia card, a card-type memory (for example, an SD or DX memory), a random access memory (RAM), a static random access memory (SRAM), a read-only memory (ROM), an electrically erasable programmable read-only memory (EEPROM), a programmable read-only memory (PROM), a magnetic memory, a disk, an optical disk, a server, an App application store, etc., on which a computer program is stored. When the program is executed by a processor, a method for calculating the frequency response characteristics of a hollow winding coil of arbitrary shape in a method embodiment is implemented.

[0137] It should be pointed out that, according to the needs of implementation, the various steps / components described in this application can be split into more steps / components, or two or more steps / components or partial operations of steps / components can be combined into new steps / components to achieve the purpose of the present invention.

[0138] It will be easily understood by those skilled in the art that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for calculating the frequency response characteristics of an air-core wound coil of arbitrary shape, characterized in that: include: Taking any point near the hollow winding coil as the origin of the three-dimensional reference coordinate system, the spatial parametric equation of the geometric center line of the coil bobbin is obtained; From the spatial parameter equation of the geometric center line of the coil skeleton, based on the distribution of the turns, the spatial coordinate equation of the geometric center of each turn of the coil is obtained; According to the spatial coordinate equation of the geometric center of each coil turn, the spatial parameter equation of each coil turn is obtained; According to the spatial parameter equation of each coil turn, the mutual inductance and capacitance between any two turns are obtained; Calculate the self-inductance of any wire turn and the resistance taking into account the skin effect; Based on the mutual inductance and capacitance between any two turns, as well as the self-inductance of any one turn and the resistance taking into account the skin effect, the voltage and current electrical relationship between each turn and the other turns is established, and the voltage and current electrical relationship between each turn and the other turns is combined and converted into a matrix equation form; The coefficient matrix of the matrix equation is transformed into an upper triangular or lower triangular form, and the ratio of the port voltage to the port current is obtained according to the coefficient equation in the transformed upper triangular or lower triangular matrix form, thereby obtaining the port frequency characteristics of the coil; The spatial parameter equation of the geometric center line of the coil skeleton is used to obtain the spatial coordinate equation of the geometric center of each coil turn based on the distribution of the coil turns, including: The spatial parameters of the geometric center line C of a hollow winding coil bobbin of arbitrary shape are (α(θ), β(θ), γ(θ)), where α(θ), β(θ), and γ(θ) are the parametric expressions of the center line C in the x, y, and z coordinates of the parametric equation. The projection of any point on the geometric center line on the rectangular coordinate system xOy is Q', and θ is the angle between the straight line between point Q' and the origin of the coordinate system and the positive direction of the rectangular coordinate x axis. θ i and θ i+1 are the angles θ and θ corresponding to the i-th turn and the i+1-th turn respectively. i and θ i+1 The space is composed of several Δθ, and N is the total number of windings; The coordinate expression of the geometric center of the i-th turn of the winding coil is: Where L is the length of the geometric center line, j represents the intermediate value of the calculation process, J is the value that makes the coordinate expression of the geometric center of the i-th turn valid, and δ is a positive number that approaches zero infinitely, that is, θ i+1 =θ i +JΔθ.

2. The method according to claim 1, characterized in that The spatial parameter equation of each turn is: Among them, r is the radius of the circular cross section of the skeleton, t represents the intermediate parameter of the calculation process, each turn is divided into N1 parts, α ′ (θ i ), β ′ (θ i ),γ ′ (θ i ) are α(θ i ),β(θ i ),γ(θ i ) is the derivative of .

3. The method according to claim 2, characterized in that The mutual inductance Mij between any two turns, the i-th turn and the j-th turn, is: F=(x′(i,g)) 2 +(y′(i,g)) 2 +(z′(i,g)) 2 H=(x′(j,h)) 2 +(y′(j,h)) 2 +(z′(j,h)) 2 Where, each turn is divided into N1 equal parts, μ0 is the vacuum permeability, (x ′ (i,t),y ′ (i,t),z ′ (i,t)) is the derivative of (x(i,t),y(i,t),z(i,t)) with respect to t, and h and g represent the intermediate values ​​of the calculation process.

4. The method according to claim 3, characterized in that The self-inductance L of any turn i i for: Among them, r l is the radius of the winding.

5. The method according to claim 4, characterized in that The electrical relationship between the voltage and current of the i-th turn and other turns is: Among them, R i is the resistance of the ith turn considering the skin effect, I i is the branch current of the i-th turn, U i is the terminal voltage of the ith turn, U N is the terminal voltage of the Nth turn, I S is the input current of the coil, ω=2πf, f is the frequency, C i,j is the capacitance between the ith and jth turns, C S is the parasitic capacitance of the impedance analyzer probe.

6. The method according to claim 5, characterized in that The method of converting the voltage and current electrical relationship between the i-th turn and other turns into a matrix form is: and in, Z i =(jωL i +R i )。 7. The method according to claim 6, characterized in that The method to transform the coefficient matrix of the matrix equation into upper triangular or lower triangular form is: Will Transformed into and substitute Zhong Ke De (A-ZB -1 C) into the form of an upper triangle, that is (A-ZB -1 C)=DE, E is an upper triangular matrix, and D and E are intermediate matrices generated during the calculation process.

8. The method according to claim 7, characterized in that Depend on Get the ratio of port voltage and port current, F=D -1 ZB -1 ; Depend on Get the frequency response characteristics of the coil or the ratio of the port voltage to the port current, where Z I (f), R(f) and L(f) are the frequency-dependent port input impedance, equivalent resistance and equivalent inductance of the coil, respectively.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 8 are implemented.

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