Design method and device of low-magnetic-leakage excitation coil capable of generating high-uniformity magnetic field

Abstract

The invention provides a low-magnetic-leakage excitation coil design method and device capable of generating a high-uniformity magnetic field, and belongs to the technical field of magnetic field control, and the method comprises the steps: determining the target magnetic induction intensity and the length of a target uniformity region; based on a pre-constructed two-dimensional distribution function of the uniform region length and the central magnetic field intensity, determining the size parameters of the low-magnetic-leakage excitation coil corresponding to the target magnetic induction intensity and the target uniform region length by using an interpolation method or a table look-up method; based on the size parameters and the condition that the magnetic moment of the low-magnetic-leakage excitation coil is zero, the ratio of the number of turns inside and outside the low-magnetic-leakage excitation coil is determined; based on the required target magnetic induction intensity and target uniform region length, the designed low-magnetic-flux-leakage excitation coil enables the system to be in a low-magnetic-flux-leakage state externally, magnetic interference to surrounding equipment is reduced, and the measurement precision is effectively improved.

Description

Technical Field

[0001] The present invention relates to the field of magnetic field control technology, and in particular to a method and device for designing a low-leakage magnetic field coil capable of generating a highly uniform magnetic field. Background Art

[0002] As magnetic field sensors are increasingly developing in the direction of high precision and high-tech, they are widely used in the fields of magnetic target detection, geomagnetic navigation, attitude measurement, ballistic magnetic correction, ship demagnetization, etc., and also play a great role in space science, geophysics, resource exploration, environmental protection, biomedicine, aviation and navigation, component detection and other fields closely related to national economic activities. The research on various ultra-high performance magnetic sensors based on different physical mechanisms is currently the most popular research direction of magnetic testing technology.

[0003] The generation of artificial controllable magnetic fields is generally inseparable from coils. For the reproduction of extremely weak magnetic fields, due to the existence of the geomagnetic field and the environmental interference magnetic field, the required magnetic field conditions are generally established through coils based on active shielding and passive shielding. The most common method is to directly use coils to reproduce the magnetic field in the shielding equipment. When using ordinary coils in combination with shielding systems, the high magnetic permeability of the shielding layer changes the magnetic lines of force of the ordinary magnetic field coil, which usually brings about a series of problems such as changes in coil constants, changes in the magnetic field uniformity zone, nonlinearity of the magnetic field, and magnetization of the shielding tube. With the surge in spacecraft missions, magnetic field measurement has put forward very high requirements in terms of time, space, accuracy, equipment and instruments, and the above methods can no longer meet these requirements.

[0004] Therefore, how to design a low-leakage magnetic excitation coil that can generate a highly uniform magnetic field to meet the needs of high-precision magnetic measurement and control of spacecraft has become a technical problem that technical personnel in this field urgently need to solve. Summary of the invention

[0005] The present invention provides a method and device for designing a low-leakage magnetic excitation coil capable of generating a highly uniform magnetic field, so as to solve the defect in the prior art that the coil cannot meet the requirements of high-precision magnetic measurement and control of spacecraft.

[0006] In a first aspect, the present invention provides a method for designing a low-leakage magnetic field coil capable of generating a highly uniform magnetic field, comprising:

[0007] Determine the target magnetic induction intensity and the target uniform zone length;

[0008] Based on a pre-constructed two-dimensional distribution function of the uniform zone length and the central magnetic field intensity, the dimension parameters of the low leakage magnetic excitation coil corresponding to the target magnetic induction intensity and the target uniform zone length are determined by using an interpolation method or a table lookup method;

[0009] Based on the size parameters and the condition that the magnetic moment of the low leakage magnetic field coil is zero, determining the ratio of the inner and outer turns of the low leakage magnetic field coil;

[0010] The low leakage magnetic field coils include a first group 1, 2 and a second group 3, 4, and the magnetic moment is zero under the condition that:

[0011] N 34 =k r N 12 ;

[0012]

[0013] Among them, N 12 and N 34 are the number of turns of the first coil 1, 2 and the second coil 3, 4, respectively, r 12 and r 34 are the radii of the first coil 1, 2 and the second coil 3, 4 respectively; d 12 and d 34 are the thicknesses of the first coil 1, 2 and the second coil 3, 4 respectively; the radial integral variable h is the height from the inner diameter of the coil to the integral point along the radial direction; d 12 and d 34 It is equal to the number of coil winding layers multiplied by the diameter of the enameled wire.

[0014] According to a method for designing a low leakage magnetic excitation coil capable of generating a high uniform magnetic field provided by the present invention, before determining the target magnetic induction intensity and the target uniform zone length, the method further includes:

[0015] Based on the steady-state magnetic induction intensity formula, the first functional relationship between the low leakage magnetic field coil constant and the number of coil turns, size and position is determined;

[0016] Based on the uniformity length, determining a second functional relationship between the uniformity length and the number of coil turns, the size, and the position;

[0017] Based on the first functional relationship and the second functional relationship, a two-dimensional distribution function of the uniform area length and the central magnetic field intensity is constructed.

[0018] According to a method for designing a low leakage magnetic field coil capable of generating a highly uniform magnetic field provided by the present invention, a two-dimensional distribution function of uniform zone length and central magnetic field intensity is constructed based on the first functional relationship and the second functional relationship, including:

[0019] Determine the constraints of zero magnetic moment and centrosymmetry respectively;

[0020] Based on the constraint conditions and in combination with the first functional relationship and the second functional relationship, a two-dimensional distribution function of the uniform area length and the central magnetic field intensity is constructed.

[0021] According to a method for designing a low leakage magnetic field coil capable of generating a high uniform magnetic field provided by the present invention, the constraint condition for the magnetic moment to be zero is:

[0022] N1r1 2 +N2 2 r2 2 =N3 2 r3 2 +N4 2 r4 2 ;

[0023] The central symmetric constraint is:

[0024] r1=r2; r3=r4; N1=N2; N3=N4;

[0025] x1=-x2=-r1 / 2; x3=-x4=-r3 / 2;

[0026] Wherein r1 and r2 represent the coil radii of the first group 1 and 2 respectively, r3 and r4 represent the coil radii of the second group 3 and 4 respectively, N1 and N2 represent the number of coil turns of the first group 1 and 2 respectively, N3 and N4 represent the number of coil turns of the second group 3 and 4 respectively, x1 and x2 represent the positions of the coils of the first group 1 and 2 on the x-axis respectively, and x3 and x4 represent the positions of the coils of the second group 3 and 4 on the x-axis respectively.

[0027] According to a method for designing a low leakage magnetic field coil capable of generating a highly uniform magnetic field provided by the present invention, based on the constraint conditions, combining the first functional relationship and the second functional relationship, constructing a two-dimensional distribution function of the uniform zone length and the central magnetic field intensity, comprising:

[0028] Based on the constraint condition, combining the first functional relationship and the second functional relationship, a coil constant constraint function and a uniform region length constraint function are obtained;

[0029] Based on the preset number of turns, the coil constant constraint function and the uniform region length constraint function are optimized to obtain a two-dimensional distribution function of the uniform region length and the central magnetic field intensity.

[0030] According to a design method for a low leakage magnetic field coil capable of generating a high uniform magnetic field provided by the present invention, the coil constant constraint function is:

[0031] K B =f1(N 12 , N 34 , r 12 , r 34 );

[0032] The uniform region length constraint function is:

[0033] X L =f2(N 12 , N 34 , r 12 , r 34 );

[0034] Among them, K B represents the low leakage field coil constant, X L represents the length of the uniform area; r 12 and r 34 are the radii of the coils numbered 1 and 2 in the first group and 3 and 4 in the second group; where N 12 and N 34 are the numbers of winding turns of the first group 1, 2 and the second group 3, 4 coils respectively, f1 represents the first functional relationship, and f2 represents the second functional relationship.

[0035] According to a design method for a low leakage magnetic field coil capable of generating a highly uniform magnetic field provided by the present invention, the two-dimensional distribution function of the uniform zone length and the central magnetic field intensity is:

[0036] (K B , X L )=f12(r 12 , r 34 );

[0037] (r 12 , r 34 )=f12 -1 (K B , X L );

[0038] Among them, f12 -1 It is the inverse function of f12.

[0039] According to a design method for a low leakage magnetic field coil capable of generating a high uniform magnetic field provided by the present invention, the steady-state magnetic induction intensity formula is:

[0040] B=Σ i＝1 4 Σ j＝1 NiL [μ0I / 2(N i / N iL L i )][(x i +L i / 2-x) / (R ij 2 +(x i +L i / 2-x) 2 ) 3 / 2 +

[0041] (-x i +Li / 2+x) / (R ij 2 +(-x i +L i / 2+x) 2 ) 3 / 2 ];

[0042] Where μ0 is the vacuum permeability, xi is the x-axis coordinate of point i on the axis, x1, x2, x3, x4 are the x-axis positions of the first coil 1, 2 and the second coil 3, 4, r1, r2, r3, r4 are the radii of the first coil 1, 2 and the second coil 3, 4, R ij is the radius of the jth layer of the ith coil, N iL is the total number of layers of the ith coil, N i is the number of turns of the ith coil, I represents the current, L i represents the spacing of the i-th coil.

[0043] In a second aspect, the present invention provides a low leakage magnetic field coil design device capable of generating a high uniform magnetic field, comprising:

[0044] A first determination module is used to determine the target magnetic induction intensity and the target uniform area length;

[0045] A second determination module is used to determine the size parameters of the low leakage magnetic excitation coil corresponding to the target magnetic induction intensity and the target uniform zone length by using an interpolation method or a table lookup method based on a pre-constructed two-dimensional distribution function of the uniform zone length and the central magnetic field strength;

[0046] A third determination module is used to determine the ratio of the inner and outer turns of the low leakage magnetic excitation coil based on the size parameter and the condition that the magnetic moment of the low leakage magnetic excitation coil is zero;

[0047] The low leakage magnetic field coils include a first group 1, 2 and a second group 3, 4, and the magnetic moment is zero under the condition that:

[0048] N 34 =k r N 12 ;

[0049]

[0050] Among them, N 12 and N 34 are the number of turns of the first coil 1, 2 and the second coil 3, 4, respectively, r 12 and r 34 are the radii of the first coil 1, 2 and the second coil 3, 4 respectively; d 12 and d 34are the thicknesses of the first coil 1, 2 and the second coil 3, 4 respectively; the radial integral variable h is the height from the inner diameter of the coil to the integral point along the radial direction; d 12 and d 34 It is equal to the number of coil winding layers multiplied by the diameter of the enameled wire.

[0051] In a third aspect, the present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, it implements a method for designing a low leakage magnetic excitation coil capable of generating a highly uniform magnetic field as described in any one of the above-mentioned methods.

[0052] In a fourth aspect, the present invention further provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements a method for designing a low-leakage magnetic excitation coil that can generate a highly uniform magnetic field as described in any of the above.

[0053] In a fifth aspect, the present invention further provides a computer program product, comprising a computer program, which, when executed by a processor, implements any of the above-described methods for designing a low-leakage magnetic excitation coil capable of generating a highly uniform magnetic field.

[0054] The present invention provides a method and device for designing a low leakage magnetic excitation coil that can generate a high uniform magnetic field, comprising determining a target magnetic induction intensity and a target uniform zone length; determining the size parameters of the low leakage magnetic excitation coil corresponding to the target magnetic induction intensity and the target uniform zone length based on a pre-constructed two-dimensional distribution function of the uniform zone length and the central magnetic field intensity by using an interpolation method or a table lookup method; determining the ratio of the inner and outer turns of the low leakage magnetic excitation coil based on the size parameters and the condition that the magnetic moment of the low leakage magnetic excitation coil is zero; and designing a low leakage magnetic excitation coil based on the required target magnetic induction intensity and the target uniform zone length, wherein the system is in a low leakage magnetic state to the outside, reduces magnetic interference to surrounding equipment, and effectively improves measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0056] Figure 1 is a flow chart of a method for designing a low-leakage magnetic field coil capable of generating a highly uniform magnetic field provided in this embodiment;

[0057] Figure 2 is a schematic diagram of the assembly structure of the low-leakage magnetic excitation coil provided in this embodiment;

[0058] Figure 3 Schematic diagram of the structure of a low leakage magnetic field coil design device capable of generating a high uniform magnetic field provided in this embodiment;

[0059] Figure 4 It is a schematic diagram of the structure of the electronic device provided in this embodiment. DETAILED DESCRIPTION

[0060] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0061] Figure 1 is a flow chart of a method for designing a low leakage magnetic field coil capable of generating a highly uniform magnetic field provided in this embodiment, Figure 2 It is a schematic diagram of the assembly structure of the low-leakage magnetic excitation coil provided in this embodiment.

[0062] like Figure 1 As shown, the embodiment of the present invention provides a method for designing a low leakage magnetic field coil that can generate a high uniform magnetic field. It mainly includes the following steps:

[0063] 101. Determine the target magnetic induction intensity and the length of the target uniform zone.

[0064] In a specific implementation process, the low leakage magnetic field excitation coil is composed of two groups of inner and outer coaxial coils. The low leakage magnetic field excitation coil has various forms, and each group of coils can be in the form of a single coil (solenoid), a double coil (Helmholtz coil) or a quad coil (Wedrich coil), etc. The inner and outer groups of coils are connected in series, and the current is reversed. By adjusting the parameters of the inner and outer groups of coils (size, number of turns and relative position), the total magnetic moment of the low leakage magnetic field excitation coil is zero, and the magnetic induction intensity in the coil working area is the difference between the magnetic induction intensity generated by the inner and outer groups of coils, which is reflected in the condition of ensuring a certain excitation area. The leakage magnetic field is greatly reduced. Therefore, the low leakage magnetic field excitation coil is defined as a low leakage magnetic field excitation coil.

[0065] When designing a low leakage magnetic excitation coil, two important indicators must be considered, namely the uniformity of the working area and the magnetic induction intensity of the working area. The quantitative indicator is the uniform area length X that meets a certain uniformity. L The maximum magnetic induction intensity B in normal operation at the center of the uniform area maxDue to the limitation of the use space, the design parameters of the low leakage magnetic excitation coil are required to be optimized to meet the design index requirements and save cost and space. Therefore, the two important indicators in this embodiment are the target magnetic induction intensity and the target uniform zone length. Since the low leakage magnetic excitation coil has various forms, this embodiment takes the low leakage magnetic excitation coil composed of Helmholtz coil as an example to design the parameters of the low magnetic leakage magnetic excitation coil.

[0066] The target magnetic induction intensity and the target uniform zone length are the required magnetic induction intensity and the required uniform zone length, thereby ensuring that the designed low leakage magnetic excitation coil can meet the requirements for magnetic induction intensity and uniform zone length.

[0067] 102. Based on the pre-constructed two-dimensional distribution function of the uniform zone length and the central magnetic field intensity, the dimension parameters of the low leakage magnetic excitation coil corresponding to the target magnetic induction intensity and the target uniform zone length are determined by using the interpolation method or the table lookup method.

[0068] The design of low leakage magnetic field coil parameters is implemented in two steps. The first step is to design the size of the low leakage magnetic field coil, and the second step is to design the number of turns of the low leakage magnetic field coil. Figure 2 As shown, it is a schematic diagram of the assembly of the low leakage magnetic field coil, C1 and C2 are the first group of coils 1, 2, C3 and C4 are the second group of coils 3, 4, and the radial dimensions of each pair of coils C1:C2 and C3:C4 are the same, and each pair is centrally symmetrical in sequence.

[0069] Through the pre-constructed two-dimensional distribution function of uniform zone length and central magnetic field intensity, the design index of low leakage magnetic excitation coil (K B , X L ) and low leakage magnetic field coil (r 12 , r 34 ) are related to the function f12, one-to-one. Given a set (r 12 , r 34 ) value can be solved to obtain a set of coil indexes (K B , X L ); N is given uniformly and discretely within a certain range x *N y Coil radius parameter (r 12 , r 34 ), we can get N x *N y Coil index (K B , X L ). Below is (B0, X L ) as the coil index, where B0 = K B I0, I0 is the unit current intensity, and (K B , X L ) are completely equivalent.

[0070] Solve the radius r of the inner and outer coils of the low leakage magnetic excitation coil respectively 12 With r 34 . As the coil uniform area length X L The two-dimensional distribution function of the central magnetic field intensity B0 is used to obtain a set of low leakage excitation coil design parameters (K B , X L ) to find the corresponding low leakage excitation coil size parameters, that is, the radius of the inner and outer coils (r 12 , r 34 ).

[0071] 103. Based on the size parameters and the condition that the magnetic moment of the low leakage magnetic excitation coil is zero, determine the ratio of the inner and outer turns of the low leakage magnetic excitation coil.

[0072] The magnetic moment of the low leakage excitation coil is zero, satisfying the condition N 12 r 12 2 =N 34 r 34 2 , we can calculate the ratio of the number of turns of the inner and outer coils. Since the size effect of the coil is not taken into account, in fact, each set of coils has a certain thickness and length. Especially when the wire diameter is thicker and the number of turns is larger, the size effect of the coil cannot be ignored. Therefore, the condition of zero magnetic moment is adopted as formula (1):

[0073]

[0074] Among them, N 12 and N 34 are the number of turns of the first coil 1, 2 and the second coil 3, 4, respectively, r 12 and r 34 are the radii of the first coil 1, 2 and the second coil 3, 4 respectively; d 12 and d 34 are the thicknesses of the first coil 1, 2 and the second coil 3, 4 respectively; the radial integral variable h is the height from the inner diameter of the coil to the integral point along the radial direction; d 12 and d 34 It is equal to the number of coil winding layers multiplied by the diameter of the enameled wire. Φ d The number of turns of the low leakage magnetic field coil should be kept as even as possible to eliminate the magnetic moment deviation caused by the helical current.

[0075] Solve the uniform area length X of the low leakage excitation coil L The central magnetic field strength B0 changes with the radius r of the inner and outer coils. 12 With r 34 The two-dimensional distribution function of satisfies the condition that the magnetic moment is zero, as shown in formulas (2) and (3):

[0076] N34 =k r N 12 (2)

[0077]

[0078] The number of coil turns N is calculated using formula (2) 34 It is not an integer or an even number, so it needs to be rounded to an even number and then 12 and r 34 Make corrections. 34 Take a smaller value, k r Too small; when N 34 Taking a larger value, kr is too large. Considering the distribution law of design indicators with the inner and outer diameters of the coil, the coil parameters corresponding to point B are generally taken.

[0079] For example, given a set of low leakage magnetic field coil design specifications: X L =12cm, B0=2Gs, through the calculation of the above embodiment, the parameter r can be obtained 12 =29cm, r 34 =40cm.

[0080] Furthermore, based on the above embodiment, this embodiment also includes constructing a two-dimensional distribution function of the uniform area length and the central magnetic field intensity, as follows:

[0081] One of the design indicators of low leakage magnetic field coils, the calculation formula for the steady-state magnetic induction intensity generated by the coil is as follows:

[0082] B=K B I (4)

[0083] B is the magnetic induction intensity generated by the coil, in Tesla (T); K B is the low leakage field coil constant, in Tesla per ampere (T / A); I is the current intensity flowing through the coil, in amperes (A). B is the number of coil turns N i0 , size r i and position x i The first functional relationship f1, where i=1,2,3,4.

[0084] K B =f1(N i0 , r i , x i )(5)

[0085] The second design index of low leakage magnetic field coil is the uniform zone length X L , meet the uniformity requirements (such as 0.3%). L is the number of coil turns N i0, size r i and position x i The second functional relationship f2, where i=1,2,3,4.

[0086] X L =f2(N i0 , r i , x i ) (6)

[0087] Finally, based on the first functional relationship and the second functional relationship, a two-dimensional distribution function of the uniform area length and the central magnetic field intensity is constructed.

[0088] Among them, the constraint condition that the total magnetic moment of the low leakage magnetic excitation coil is zero requires:

[0089] N1r1 2 +N2 2 r2 2 =N3 2 r3 2 +N4 2 r4 2 (7)

[0090] The low leakage magnetic field coil meets the requirements of central symmetry and the structure meets the following relationship:

[0091] r1=r2; r3=r4; N1=N2; N3=N4(8)

[0092] x1=-x2=-r1 / 2; x3=-x4=-r3 / 2(9)

[0093] For the low leakage magnetic field coil composed of two pairs of Helmholtz coils, considering the constraints such as symmetry and zero total magnetic moment, the coil constant K B and uniform zone length X L It can be simplified to the following constraint function:

[0094] K B =f1(N 12 , N 34 , r 12 , r 34 ) (10)

[0095] X L =f2(N 12 , N 34 , r 12 , r 34 ) (11)

[0096] N 12 r 12 2 =N 34 r 342 (12)

[0097] Among them, r1 and r2 represent the coil radius of the first group 1 and 2 respectively, r3 and r4 represent the coil radius of the second group 3 and 4 respectively, N1 and N2 represent the number of coil turns of the first group 1 and 2 respectively, N3 and N4 represent the number of coil turns of the second group 3 and 4 respectively, x1 and x2 represent the position of the coil of the first group 1 and 2 on the x-axis respectively, x3 and x4 represent the position of the coil of the second group 3 and 4 on the x-axis respectively, and the x-axis can be Figure 2 The dotted line shown, the center symmetry point of the coils of the first group 1, 2 and the coils of the second group 3, 4 is the coordinate origin. B represents the low leakage field coil constant, X L represents the length of the uniform area; r 12 and r 34 are the radii of the coils numbered 1 and 2 in the first group and 3 and 4 in the second group; where N 12 and N 34 are the numbers of winding turns of the first group 1, 2 and the second group 3, 4 coils respectively, f1 represents the first functional relationship, and f2 represents the second functional relationship.

[0098] Given a design indicator X L , K B , the size r of each coil in the low leakage excitation coil can be optimized and calculated i , position x i and the number of coil turns N i0 For example, setting N 12 = 100 turns, then adjust the coefficient k and take the integer operation, finally, the coil constant K B and uniform zone length X L It can be simplified to the following function:

[0099] (K B , X L )=f12(r 12 , r 34 ) (13)

[0100] (r 12 , r 34 )=f12 -1 (K B , X L ) (14)

[0101] It can be seen that the design index (K B , X L ) and low leakage magnetic field coil size (r 12 , r 34 ) are mapped to each other with respect to the function f12, that is, the two-dimensional distribution function of the uniform zone length and the central magnetic field intensity is obtained. -1is the inverse function of f12, so given a set (r 12 , r 34 ) value, a set of coil indexes (K B , X L ).

[0102] Use function f12 to calculate the design index of low leakage excitation coil (K B , X L ). Given a set of parameters r 12 , r 34 , N 12 , N 34 and current I0, solve for the magnetic field strength B0 at the center of the low leakage magnetic excitation coil, and get K B =B0 / I0; calculate the magnetic field intensity distribution B along the central axis of the low leakage magnetic excitation coil i , the uniform zone length X of the low leakage magnetic field coil L Is to satisfy the magnetic field uniformity ε i The length of the interval is less than 0.3%. The expression of magnetic field uniformity is:

[0103] ε i =(B0-B i ) / B0(15)

[0104] On the basis of the above embodiment, in this embodiment, it is assumed that the current flowing through the circular coil with a radius r is I, and the magnetic induction intensity at point P on its axis at a distance x from the center of the circle is:

[0105] B=μ0Ir 2 / 2(r 2 +x 2 ) 3 / 2 (16)

[0106] Considering the coil as an ideal current loop and ignoring the size of the enameled wire, the magnetic field generated by the low leakage magnetic excitation coil at a certain position P on the central axis is the superposition of the magnetic induction intensity generated by the four circular coils:

[0107] B=μ0 / 2[Ir1 2 / (r1 2 +(x i -x1) 2 ) 3 / 2 +

[0108] Ir2 2 / (r2 2 +(x i -x2) 2 ) 3 / 2 +Ir3 2 / (r3 2 +(x i -x3) 2) 3 / 2 +Ir4 2 / (r4 2 +(x i -x4) 2 ) 3 / 2 ](17)

[0109] Each coil is composed of a spiral coil wound on a ring. Assuming that the wire is thin and each coil is wound tightly, each coil can be regarded as a circular coil. According to the principle of magnetic field superposition, the magnetic field at a point on the axis of the low leakage magnetic excitation coil is synthesized by the magnetic field generated by the current of each coil. The formula for the magnetic field generated by a single-layer solenoid of a single coil at point i on the axis is as follows:

[0110] B=Σ i＝1 4 Σ j＝1 NiL [μ0I / 2(N i / N iL L i )][(x i +L i / 2-x) / (R ij 2 +(x i +L i / 2-x) 2 ) 3 / 2 +

[0111] (-x i +L i / 2+x) / (R ij 2 +(-x i +L i / 2+x) 2 ) 3 / 2 ](18);

[0112] Where μ0 is the vacuum permeability, xi is the x-axis coordinate of point i on the axis, x1, x2, x3, x4 are the x-axis positions of the first coil 1, 2 and the second coil 3, 4, r1, r2, r3, r4 are the radii of the first coil 1, 2 and the second coil 3, 4, R ij is the radius of the jth layer of the ith coil, N iL is the total number of layers of the ith coil, N i is the number of turns of the ith coil, I represents the current, L i represents the spacing of the i-th coil.

[0113] First, sum the number of layers of a single coil, then sum the number of coils, and you get the total magnetic field strength at point i. In fact, in the space outside the central axis of the low-leakage excitation coil, the analytical form of the function f12 is solved numerically in the calculation.

[0114] By adopting the design method of the low leakage magnetic excitation coil that can generate a high uniform magnetic field of the present invention, the magnetic induction intensity at any point in the low leakage magnetic excitation system can be calculated, and then the magnetic field distribution of the entire coil system can be obtained, and the magnetic field distribution law can be found to obtain the magnetic field area that meets the design requirements. The coil system is in a low leakage magnetic state to the outside, which reduces the magnetic interference to the surrounding equipment and effectively improves the measurement accuracy. The coil system has a simple structure and high excitation efficiency, and can achieve high-precision magnetic field measurement and control in a limited space. The magnetic field intensity of the coil is controllable, and the magnetic field uniformity area is controllable, which can be adjusted and adapted according to different test requirements. The magnetic induction intensity at a certain position of the coil system achieves extremely low leakage magnetic field of the coil system, which minimizes the interference to the surrounding equipment.

[0115] Based on the same general inventive concept, the present invention also protects a low leakage magnetic excitation coil design device that can generate a high uniform magnetic field. The low leakage magnetic excitation coil design device that can generate a high uniform magnetic field described below and the low leakage magnetic excitation coil design method that can generate a high uniform magnetic field described above can refer to each other.

[0116] Figure 3 It is a schematic structural diagram of a low leakage magnetic field coil design device capable of generating a highly uniform magnetic field provided in this embodiment.

[0117] like Figure 3 As shown, this embodiment provides a low leakage magnetic field coil design device capable of generating a high uniform magnetic field, comprising:

[0118] The first determination module 301 is used to determine the target magnetic induction intensity and the target uniform area length;

[0119] The second determination module 302 is used to determine the size parameters of the low leakage magnetic excitation coil corresponding to the target magnetic induction intensity and the target uniform area length by using an interpolation method or a table lookup method based on a pre-constructed two-dimensional distribution function of the uniform area length and the central magnetic field strength;

[0120] A third determination module 303 is used to determine the ratio of the inner and outer turns of the low leakage magnetic field coil based on the size parameter and the condition that the magnetic moment of the low leakage magnetic field coil is zero;

[0121] The low leakage magnetic field coils include the first group 1, 2 and the second group 3, 4. The condition for the magnetic moment to be zero is:

[0122] N 34 =k r N 12 ;

[0123]

[0124] Among them, N 12 and N 34are the number of turns of the first coil 1, 2 and the second coil 3, 4, respectively, r 12 and r 34 are the radii of the first coil 1, 2 and the second coil 3, 4 respectively; d 12 and d 34 are the thicknesses of the first coil 1, 2 and the second coil 3, 4 respectively; the radial integral variable h is the height from the inner diameter of the coil to the integral point along the radial direction; d 12 and d 34 It is equal to the number of coil winding layers multiplied by the diameter of the enameled wire.

[0125] Figure 4 It is a schematic diagram of the structure of the electronic device provided in this embodiment.

[0126] like Figure 4 As shown, the electronic device may include: a processor 410, a communication interface 420, a memory 430 and a communication bus 440, wherein the processor 410, the communication interface 420 and the memory 430 communicate with each other through the communication bus 440. The processor 410 may call the logic instructions in the memory 430 to execute a design method for a low leakage magnetic field excitation coil that can generate a high uniform magnetic field, the method comprising: determining a target magnetic induction intensity and a target uniform zone length; based on a pre-constructed two-dimensional distribution function of the uniform zone length and the central magnetic field intensity, using an interpolation method or a table lookup method, determining the size parameters of the low leakage magnetic field excitation coil corresponding to the target magnetic induction intensity and the target uniform zone length; based on the size parameters and the condition that the magnetic moment of the low leakage magnetic field excitation coil is zero, determining the ratio of the inner and outer turns of the low leakage magnetic field excitation coil.

[0127] In addition, the logic instructions in the above-mentioned memory 430 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when it is sold or used as an independent product. Based on this understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art or the part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0128] On the other hand, the present invention also provides a computer program product, which includes a computer program. The computer program can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the low leakage magnetic excitation coil design method that can generate a high uniform magnetic field provided by the above methods. The method includes: determining the target magnetic induction intensity and the target uniform zone length; based on a pre-constructed two-dimensional distribution function of the uniform zone length and the central magnetic field intensity, using an interpolation method or a table lookup method, determining the size parameters of the low leakage magnetic excitation coil corresponding to the target magnetic induction intensity and the target uniform zone length; based on the size parameters and the condition that the magnetic moment of the low leakage magnetic excitation coil is zero, determining the ratio of the inner and outer turns of the low leakage magnetic excitation coil.

[0129] On the other hand, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, is implemented to execute the low leakage magnetic excitation coil design method that can generate a high uniform magnetic field provided by the above-mentioned methods, the method comprising: determining a target magnetic induction intensity and a target uniform zone length; based on a pre-constructed two-dimensional distribution function of the uniform zone length and the central magnetic field intensity, using an interpolation method or a table lookup method, determining the size parameters of the low leakage magnetic excitation coil corresponding to the target magnetic induction intensity and the target uniform zone length; based on the size parameters and the condition that the magnetic moment of the low leakage magnetic excitation coil is zero, determining the ratio of the inner and outer turns of the low leakage magnetic excitation coil.

[0130] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0131] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0132] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for designing a low leakage magnetic field coil capable of generating a high uniform magnetic field, characterized in that: include: Determine the target magnetic induction intensity and the target uniform zone length; Based on a pre-constructed two-dimensional distribution function of the uniform zone length and the central magnetic field intensity, the dimension parameters of the low leakage magnetic excitation coil corresponding to the target magnetic induction intensity and the target uniform zone length are determined by using an interpolation method or a table lookup method; Based on the size parameters and the condition that the magnetic moment of the low leakage magnetic field coil is zero, determining the ratio of the inner and outer turns of the low leakage magnetic field coil; The low leakage magnetic field coils include a first group 1, 2 and a second group 3, 4, and the magnetic moment is zero under the condition that: N 34 =k r N 12 ; Among them, N 12 and N 34 are the number of turns of the first coil 1, 2 and the second coil 3, 4, respectively, r 12 and r 34 are the radii of the first coil 1, 2 and the second coil 3, 4 respectively; d 12 and d 34 are the thicknesses of the first coil 1, 2 and the second coil 3, 4 respectively; the radial integral variable h is the height from the inner diameter of the coil to the integral point along the radial direction; d 12 and d 34 It is equal to the number of coil winding layers multiplied by the diameter of the enameled wire.

2. The method for designing a low leakage magnetic field coil capable of generating a high uniform magnetic field according to claim 1, characterized in that: Before determining the target magnetic induction intensity and the target uniform zone length, the method further includes: Based on the steady-state magnetic induction intensity formula, the first functional relationship between the low leakage magnetic field coil constant and the number of coil turns, size and position is determined; Based on the uniformity length, determining a second functional relationship between the uniformity length and the number of coil turns, the size, and the position; Based on the first functional relationship and the second functional relationship, a two-dimensional distribution function of the uniform area length and the central magnetic field intensity is constructed.

3. The method for designing a low leakage magnetic field coil capable of generating a high uniform magnetic field according to claim 2, characterized in that: The constructing of a two-dimensional distribution function of the uniform area length and the central magnetic field intensity based on the first functional relationship and the second functional relationship includes: Determine the constraints of zero magnetic moment and centrosymmetry respectively; Based on the constraint conditions and in combination with the first functional relationship and the second functional relationship, a two-dimensional distribution function of the uniform area length and the central magnetic field intensity is constructed.

4. The method for designing a low leakage magnetic field coil capable of generating a high uniform magnetic field according to claim 3, characterized in that: The constraint condition for the magnetic moment to be zero is: N1r1 2 +N2 2 r2 2 =N3 2 r3 2 +N4 2 r4 2 ; The central symmetric constraint is: r1=r2; r3=r4; N1=N2; N3=N4; x1=-x2=-r1 / 2; x3=-x4=-r3 / 2; Wherein r1 and r2 represent the coil radii of the first group 1 and 2 respectively, r3 and r4 represent the coil radii of the second group 3 and 4 respectively, N1 and N2 represent the number of coil turns of the first group 1 and 2 respectively, N3 and N4 represent the number of coil turns of the second group 3 and 4 respectively, x1 and x2 represent the positions of the coils of the first group 1 and 2 on the x-axis respectively, and x3 and x4 represent the positions of the coils of the second group 3 and 4 on the x-axis respectively.

5. The method for designing a low leakage magnetic field coil capable of generating a high uniform magnetic field according to claim 4, characterized in that: The constructing of a two-dimensional distribution function of the uniform area length and the central magnetic field intensity based on the constraint condition and in combination with the first functional relationship and the second functional relationship comprises: Based on the constraint condition, combining the first functional relationship and the second functional relationship, a coil constant constraint function and a uniform region length constraint function are obtained; Based on the preset number of turns, the coil constant constraint function and the uniform region length constraint function are optimized to obtain a two-dimensional distribution function of the uniform region length and the central magnetic field intensity.

6. The method for designing a low leakage magnetic field coil capable of generating a high uniform magnetic field according to claim 5, characterized in that: The coil constant constraint function is: K B =f1(N 12 ,N 34 ,r 12 ,r 34 ); The uniform region length constraint function is: X L =f2(N 12 ,N 34 ,r 12 ,r 34 ); Among them, K B represents the low leakage field coil constant, X L represents the length of the uniform area; r 12 and r 34 are the radii of the coils numbered 1 and 2 in the first group and 3 and 4 in the second group; where N 12 and N 34 are the numbers of winding turns of the first group 1, 2 and the second group 3, 4 coils respectively, f1 represents the first functional relationship, and f2 represents the second functional relationship.

7. The method for designing a low leakage magnetic field coil capable of generating a high uniform magnetic field according to claim 6, characterized in that: The two-dimensional distribution function of the uniform zone length and the central magnetic field intensity is: (K B ,X L )=f12(r 12 ,r 34 ); (r 12 ,r 34 )=f12 -1 (K B ,X L ); Among them, f12 -1 It is the inverse function of f12.

8. The method for designing a low leakage magnetic field coil capable of generating a high uniform magnetic field according to any one of claims 2 to 7, characterized in that: The steady-state magnetic induction intensity formula is: B=S i＝1 4 S j＝1 NiL [μ0I / 2(N i / N iL L i )][(x i +L i / 2-x) / (R ij 2 +(x i +L i / 2-x) 2 ) 3 / 2 + (-x i +L i / 2+x) / (R ij 2 +(-x i +L i / 2+x) 2 ) 3 / 2 ]; Where μ0 is the vacuum permeability, xi is the x-axis coordinate of point i on the axis, x1, x2, x3, x4 are the x-axis positions of the first coil 1, 2 and the second coil 3, 4, r1, r2, r3, r4 are the radii of the first coil 1, 2 and the second coil 3, 4, R ij is the radius of the jth layer of the ith coil, N iL is the total number of layers of the ith coil, N i is the number of turns of the ith coil, I represents the current, and L i represents the spacing of the i-th coil.

9. A low leakage magnetic field coil design device capable of generating a high uniform magnetic field, characterized in that: include: A first determination module is used to determine the target magnetic induction intensity and the target uniform area length; A second determination module is used to determine the size parameters of the low leakage magnetic excitation coil corresponding to the target magnetic induction intensity and the target uniform zone length by using an interpolation method or a table lookup method based on a pre-constructed two-dimensional distribution function of the uniform zone length and the central magnetic field strength; A third determination module is used to determine the ratio of the inner and outer turns of the low leakage magnetic excitation coil based on the size parameter and the condition that the magnetic moment of the low leakage magnetic excitation coil is zero; The low leakage magnetic field coils include a first group 1, 2 and a second group 3, 4, and the magnetic moment is zero under the condition that: N 34 =k r N 12 ; Among them, N 12 and N 34 are the number of turns of the first coil 1, 2 and the second coil 3, 4, respectively, r 12 and r 34 are the radii of the first coil 1, 2 and the second coil 3, 4 respectively; d 12 and d 34 are the thicknesses of the first coil 1, 2 and the second coil 3, 4 respectively; the radial integral variable h is the height from the inner diameter of the coil to the integral point along the radial direction; d 12 and d 34 It is equal to the number of coil winding layers multiplied by the diameter of the enameled wire.

10. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the program, the method for designing a low-leakage magnetic excitation coil capable of generating a high uniform magnetic field as claimed in any one of claims 1 to 8 is implemented.

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