CN113253167B - A low-frequency complex permeability testing device and method for soft magnetic films - Google Patents
A low-frequency complex permeability testing device and method for soft magnetic films Download PDFInfo
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- CN113253167B CN113253167B CN202110515462.7A CN202110515462A CN113253167B CN 113253167 B CN113253167 B CN 113253167B CN 202110515462 A CN202110515462 A CN 202110515462A CN 113253167 B CN113253167 B CN 113253167B
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Abstract
A low-frequency complex permeability testing device and method for a soft magnetic film are characterized in that a revolving body type annular testing body with a circular bus is designed, the soft magnetic film is fixed inside the annular testing body, a coil is uniformly wound on the outer surface of the overall structure of the annular testing body, a wiring end of the coil is connected to an LCR (inductance-resistance-capacitance) meter, and the equivalent resistance and the equivalent inductance of the annular testing body containing the soft magnetic film under a low-frequency signal are tested, so that the low-frequency complex permeability of the soft magnetic film is obtained, and the purpose of calculating and evaluating hysteresis loss noise of the soft magnetic film is achieved.
Description
Technical Field
The invention relates to a device and a method for testing low-frequency complex permeability of a soft magnetic film, belonging to the technical field of magnetic material permeability measurement.
Background
The atomic Spin magnetic field measurement system based on the Spin-Exchange Relaxation-Free (SERF) technology has ultrahigh sensitivity and has wide application prospect in the fields of leading-edge scientific research, basic physical research, biomedicine and the like. The SERF atomic spin-based ultra-high sensitivity magnetic field measurement device needs a stable magnetic field environment, and generally adopts a traditional magnetic material for magnetic shielding to isolate the interference of a geomagnetic field and an environmental magnetic field. However, the hysteresis loss of the conventional magnetic material is very noisy, and has a great influence on the sensitivity of measurement. The soft magnetic film (such as permalloy film, amorphous film and the like) with high magnetic permeability as a magnetic shielding material can reduce hysteresis loss noise, provide a stable magnetic field environment for the measurement of an ultrahigh sensitive magnetic field and improve the measurement sensitivity of the magnetic field. However, the frequency range of the SERF atom spin-based ultra-high sensitivity magnetic field measurement signal is within 0-100Hz, so that it is important to accurately calculate the hysteresis loss noise of the soft magnetic film under the low-frequency signal. The complex permeability of the soft magnetic film is a key parameter for calculating hysteresis loss noise under a low-frequency signal, but the existing film complex permeability testing devices are all used for testing the complex permeability under a high-frequency signal and cannot meet the requirements. The traditional method for measuring the low-frequency-band complex permeability is used for measuring a solid annular magnetic material, and no method is used for measuring and relevant calculating the soft magnetic thin film in a sheet shape at present. Therefore, it is necessary to design a low-frequency complex permeability test apparatus and a test method for a soft magnetic thin film to calculate and evaluate hysteresis loss noise thereof.
Disclosure of Invention
The invention provides a device and a method for testing low-frequency complex permeability of a soft magnetic film. And obtaining the equivalent resistance and the equivalent inductance of the soft magnetic film under the low-frequency signal through an LCR (inductance-capacitance) meter, and obtaining the low-frequency complex permeability of the soft magnetic film, which can meet the calculation requirement of the low-frequency magnetic noise, according to the relation among the equivalent resistance, the inductance and the complex permeability.
The technical scheme of the invention is as follows:
a low-frequency complex permeability testing device for a soft magnetic film comprises an annular testing body, a coil and an LCR meter, wherein the annular testing body is of an annular revolving body structure, a bus of the annular testing body is circular, and the annular testing body comprises the soft magnetic film, a film fixing frame and an external clamping ring which are coaxially arranged; the soft magnetic film is embedded between the film fixing frame and the external clamping ring; the coil is uniformly wound on the outer surface of the annular test body, and the wiring end of the coil is connected to two ends of the LCR meter.
Preferably, the film mount include at least with the cylindrical lateral surface of the coaxial setting of annular test body, soft magnetic film ring subsides in cylindrical lateral surface, external snap ring joint is fixed soft magnetic film's the outside.
Preferably, the film fixing frame and the external snap ring are both annular revolving body structures with revolving central axes coinciding with the revolving central axis of the annular test body, the generatrix of the film fixing frame is a circle with a rectangular opening, the rectangular opening is arranged outwards, the inner edge line of the rectangular opening is the bus of the cylindrical outer side surface, and the inner edge of the rectangular opening is the rotary central line of the annular test body, so as to ensure that the soft magnetic film attached to the cylindrical outer side surface is positioned at the central position of the annular test body, and the height of the rectangular opening in the direction of the rotary central shaft of the annular test body is less than the diameter of the generatrix of the annular test body, the corresponding external clamp ring is provided with a rectangular bulge, and when the rectangular bulge is completely clamped into the rectangular opening of the film fixing frame, a revolving body type annular testing body with a round bus is formed.
Preferably, the external snap ring is equally divided into at least two clamping arms which can be mutually clamped along the revolution surface of the external snap ring, a bus forming the cylindrical outer side surface passes through the circle center of the bus of the annular test body, and the bus forming the cylindrical outer side surface is parallel to the revolution center line of the annular test body.
Preferably, the soft magnetic film is just attached to the cylindrical outer side surface by using a non-magnetic double-sided adhesive tape, so that the coil magnetizes the soft magnetic film to form a closed magnetic circuit.
Preferably, the film fixing frame and the external clamping ring are made of nonmagnetic materials, and the nonmagnetic materials comprise ABS materials and/or nylon materials.
Preferably, the thickness of the soft magnetic thin film is 0.1mm to 0.5mm, and the number of turns of the coil is determined according to the sensitivity range of the test signal and the diameter of the cylindrical outer side surface.
Preferably, the number of turns of the coil is 30 to 100 turns.
Preferably, the equivalent resistance and the equivalent inductance are measured by the LCR meter, so that the real part and the imaginary part of the complex permeability of the soft magnetic film of the annular test body are obtained.
A low-frequency complex permeability test method for soft magnetic films is characterized in that any one of the low-frequency complex permeability test devices for the soft magnetic films is used for testing the low-frequency complex permeability of the soft magnetic films, the soft magnetic films with different specifications are respectively bent into different cylinders, each soft magnetic film is respectively attached between the film fixing frame and the external clamping ring with the same specification in a coaxial ring mode to form the annular test body with a circular bus, then according to the sensitivity range of test signals and the diameter of the cylindrical soft magnetic film, a coil with 30-100 turns is uniformly wound on the outer surface of the annular test body, and the annular test body wound with the coil is connected to an LCR meter to measure equivalent resistance and equivalent inductance, so that the real part and the imaginary part of the complex permeability of the soft magnetic films are obtained.
Compared with the prior art, the invention has the advantages that: the invention relates to a device and a method for testing low-frequency complex permeability of a soft magnetic film, which are used for testing the low-frequency hysteresis loss noise of the soft magnetic film in an ultrahigh sensitive magnetic field measurement by designing a revolving body type annular test body with a round bus, fixing the soft magnetic film at the central position in the annular test body, uniformly winding wires on the outer surface of the integral structure of the annular test body, and testing the equivalent resistance and the equivalent inductance of the soft magnetic film under a low-frequency signal through a coil in combination with an LCR (inductance-resistance coefficient) meter. The testing device solves the equivalent problem that the soft magnetic film is too thin and flaky and cannot be directly wound on a coil to carry out series resistance inductance circuit by designing the annular testing body structure. Meanwhile, the soft magnetic film ring is attached to a cylindrical outer side surface which is coaxial with the annular testing body, a bus of the cylindrical outer side surface passes through the circle center of the bus of the annular testing body, the bus of the cylindrical outer side surface is parallel to the rotation center line of the annular testing body, namely the soft magnetic film is attached to the position of the average diameter of the inner diameter and the outer diameter of the annular testing body, so that the soft magnetic film is ensured to be positioned at the center of the coil in the testing process, the parameters such as the average magnetic path length and the equivalent cross-sectional area of the film are ensured to be accurate, and the testing accuracy is ensured. The outside of film mount sets up the rectangle opening that the opening is outside, corresponds external snap ring sets up the rectangle arch, promptly the outside of film mount is half I shape structure, makes external snap ring just can block into half I shape structure guarantees the film mount with external snap ring can closely laminate, and then forms the generating line and be the circular shape solid of revolution formula annular test body, this moment external snap ring should divide into the joint arm of two at least mutual buckles to the joint is in so that the joint inserts in half I shape structure. The equivalent resistance and the equivalent inductance are measured by combining the annular testing body with the LCR meter, so that the testing structure is simple, the operation is easy, other complex factors are avoided, and the testing precision is reduced. In addition, the influence of the low-frequency coil resistance is considered in the overall test method, and the accurate line resistance value is obtained through resistance frequency response curve fitting, so that the influence of the line resistance in the equivalent resistance measurement result is eliminated, and the measurement precision is improved. The soft magnetic film used as the magnetic shielding material is often required to be bent into a hollow cylindrical shape during application, and the change of stress during the bending process may affect the complex permeability of the soft magnetic film. The testing device designed by the invention can test the soft magnetic films with different bending degrees by designing the annular testing bodies with different sizes, thereby exploring the influence of the different bending degrees on the complex permeability of the soft magnetic film and evaluating the change of hysteresis loss noise in the bending use process of the soft magnetic film as a magnetic shielding material.
Drawings
FIG. 1 is a schematic diagram showing the construction of a low frequency complex permeability test apparatus for a soft magnetic thin film according to the present invention;
FIG. 2 is a schematic three-dimensional structure of an annular test body of the low-frequency complex permeability test device for the soft magnetic thin film according to the present invention;
FIG. 3 is a schematic sectional front view of an annular test body of the low-frequency complex permeability test device for soft magnetic thin films according to the present invention;
FIG. 4 is a schematic structural diagram of a front view of a film holder with a soft magnetic film adhered thereto by a non-magnetic double-sided tape in a low-frequency complex permeability testing apparatus for a soft magnetic film according to the present invention;
fig. 5 is a schematic three-dimensional structure diagram of an external snap ring of the low-frequency complex permeability testing device for the soft magnetic film according to the present invention.
The reference numbers are listed below: 1-an annular test body; 2-a coil; 3-LCR meter; 11-soft magnetic thin film; 12-a film holder; 13-external connection of a snap ring; 131-a first snap arm; 1311-snap-fit projections; 1312-a snap-in hole; 132-a second snap arm; 4-non-magnetic double-sided adhesive tape.
Detailed Description
To facilitate an understanding of the present invention, the following detailed description of the invention is provided in conjunction with the accompanying drawings. The inner part and the outer part of the invention are relative to the rotary central shaft of the annular test body 1, the part close to the rotary central shaft is the inner part, and the part far away from the rotary central shaft is the outer part.
A low-frequency complex permeability testing device for a soft magnetic thin film comprises an annular testing body 1, a coil 2 and an LCR meter 3, wherein the coil 2 is uniformly wound on the outer surface of the annular testing body 1, and a terminal of the coil 2 is connected to the LCR meter 3. As shown in fig. 2-3, the annular test body 1 is an annular revolving body structure with a circular bus, and includes a soft magnetic thin film 11, a thin film fixing frame 12 and an external snap ring 13 which are coaxially arranged; the film fixing frame 12 and the external snap ring 13 are annular revolution body structures with the revolution center axis coinciding with the revolution center axis of the annular testing body 1, as shown in fig. 3-4, the bus of the film fixing frame 12 is a circle with a rectangular opening, and the rectangular opening is arranged outwards, the inner edge of the rectangular opening passes through the center of the bus of the annular testing body 1, and the inner edge of the rectangular opening is parallel to the revolution center line of the annular testing body 1. The rectangle open-ended interior boundary line winds the rotatory round of center of rotation line of the annular test body 1 forms the cylindrical lateral surface of film mount 12, promptly cylindrical lateral surface is located the centre of a circle position of the annular test body 1 generating line. The height of the soft magnetic film 11 is equal to that of the cylindrical outer side face, and the non-magnetic double-sided adhesive tape 4 is used for just being capable of being fully attached to the cylindrical outer side face for the soft magnetic film 11 is bent to be cylindrical, so that the soft magnetic film 22 can be magnetized conveniently by the coil 2, and a closed magnetic circuit is formed. The equivalent problem that the soft magnetic film is too thin and is in a sheet shape, and a coil cannot be directly wound to carry out series resistance inductance circuit is solved. Meanwhile, the soft magnetic film is positioned at the center of the coil in the testing process, so that the parameters such as the average magnetic path length, the equivalent cross-sectional area of the film and the like are accurate, and the testing accuracy is ensured.
The sizes of the film fixing frame 12 and the external snap ring 13 can be designed according to the requirements of the width and the length of the soft magnetic film 11 to be actually tested, and the sizes are flexible. The testing of the soft magnetic films with different bending degrees can be realized by designing the annular testing bodies with different sizes, so that the influence of different bending degrees on the complex permeability of the soft magnetic film is explored, and the change of hysteresis loss noise in the bending use process of the soft magnetic film as a magnetic shielding material is evaluated.
Preferably, the height of the rectangular opening in the direction of the rotation central axis of the annular test body 1 is smaller than the diameter of a bus of the annular test body 1, the external snap ring 13 is correspondingly provided with a rectangular protrusion, and when the rectangular protrusion is completely clamped into the rectangular opening of the film fixing frame, the soft magnetic film 11 is just clamped and embedded between the film fixing frame 12 and the external snap ring 13 to form the annular test body 1 with a circular rotation body as a bus. The whole structure of the annular test body 1 is a three-dimensional ring, which is convenient for winding the copper wire coil 12.
At this time, as shown in fig. 5, the external snap ring 13 is equally divided into a first snap arm 131 and a second snap arm 132 which have the same shape and a semi-annular structure along the rotation surface thereof, and a snap protrusion 1311 and a snap hole 1312 for snap-fastening the first snap arm 131 and the second snap arm 132 into an annular shape and fastening the first snap arm 131 and the second snap arm 132 into an annular shape are respectively disposed on two cross sections of the first snap arm 131 and the second snap arm 132, so as to press the fixed soft magnetic thin film 11, thereby further fixing the soft magnetic thin film.
Preferably, the film fixing frame 12 and the external snap ring 13 are made of nonmagnetic materials, the nonmagnetic materials comprise ABS materials and/or nylon materials, the processing precision of the materials is high, and the accuracy of the size of the test structure can be ensured.
Preferably, the thickness of the soft magnetic film 11 is 0.1mm-0.5mm, and since the soft magnetic film 11 is thin, the cross-sectional area of the magnetic flux of the coil 2 is small when the coil 2 is tightly wound on the outer surface of the annular test body 1 in a solenoid type, so that the number of turns of the coil 2 can be determined according to the sensitivity range of the test signal of the LCR meter 3 and the diameter of the cylindrical outer side surface, wherein the number of turns of the coil 2 is preferably 30-100 turns.
Preferably, the equivalent resistance and the equivalent inductance are measured by the LCR table 3, so that the real part and the imaginary part of the complex permeability of the soft magnetic film of the annular test body are obtained
The relationship between the real part and the imaginary part of the specific complex permeability and the equivalent resistance and the inductance is as follows:
wherein N is the number of coil turns; ω 2 pi f is the angular frequency of the input low frequency signal; l issIs an equivalent circuit inductance, RsS is the equivalent circuit resistance, and S is the equivalent cross-sectional area of the sample (soft magnetic thin film) to be measured. l is the average magnetic path length mu0Is a vacuum complex permeability. The annular test body 1 is designed to embed the soft magnetic thin film 11 between the thin film fixing frame 12 and the external clamping ring 13, the height of the soft magnetic thin film 11 is equal to that of the cylindrical outer side surface, and a circle of non-magnetic double-sided adhesive tape 4 can be attached to the cylindrical outer side surface exactly, so that the equivalent sectional area is the product of the thickness of the soft magnetic thin film 11 and the height of the cylindrical outer side surface; the bus of the cylindrical outer side surface is designed to pass through the circle center of the bus of the annular test body, and the bus of the cylindrical outer side surface is formed to be parallel to the rotation center line of the annular test body, namely the soft magnetic film is attached to the position of the average diameter of the inner diameter and the outer diameter of the annular test body, so that the soft magnetic film is ensured to be positioned at the center of a coil in the test process, and the average magnetic path is long
The diameter of a circle formed by the circle center of the bus of the annular test body 1 around the rotation central shaft.
Considering the influence of the low-band coil resistance on the measurement result, the actually measured equivalent resistance can be expressed as:
Rs′＝Rs+Rw
wherein R iss' is the actual measured equivalent resistance, RwAs resistance of coil wire
From RsThe relationship to μ ″:
the imaginary part of the complex permeability and the line resistance can be considered as constant values in the low frequency band, so:
R′s＝Cf+Rw
wherein
Can be regarded as a constant, and then the accurate numerical value of the line resistance is obtained through the fitting of the resistance frequency response curve, thereby removing the influence of the line resistance in the equivalent resistance measurement result.
A low-frequency complex permeability test method for a soft magnetic film uses the soft magnetic film low-frequency complex permeability test device to test the low-frequency complex permeability of the soft magnetic film, respectively bends the soft magnetic films 11 with different specifications into different cylinders, respectively and coaxially attaches each soft magnetic film 11 between the film fixing frame 12 and the external clamping ring 13 with the same specification to form a circular bus bar of the annular test body 1, then according to the sensitivity range of the test signal of an LCR meter 3 and the diameter of the cylindrical soft magnetic film 11 (namely the diameter of the outer side surface of the cylinder), the outer surface of the annular test body 1 uniformly surrounds a coil 2 with 30-100 turns, the annular test body 1 wound with the coil 2 is connected to the LCR meter 3, and the equivalent resistance R is measuredSAnd equivalent inductance LSThereby obtaining the real part μ' and imaginary part μ ″ of the complex permeability of the soft magnetic film 11. The method is characterized in that data deviation caused by the line resistance of the coil is noticed, namely, when complex permeability and magnetic noise are calculated, an accurate value of the line resistance is obtained through resistance frequency response curve fitting, so that the influence of the line resistance in an equivalent resistance measurement result is eliminated, and the measurement precision is improved. It should be noted that the above-described embodiments may enable those skilled in the art to more fully understand the present invention, but do not limit the present invention in any way. Therefore, although the present invention has been described in detail with reference to the drawings and examples, it will be understood by those skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope of the invention.
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| JPS6388813A (en) * | 1986-10-01 | 1988-04-19 | Toko Inc | Inductance element |
| DE10251647B4 (en) * | 2002-10-30 | 2016-09-15 | Xylem Ip Holdings Llc | electric motor |
| JP5159193B2 (en) * | 2007-07-09 | 2013-03-06 | キヤノン株式会社 | Magnetic detection element and detection method |
| CN102603278B (en) * | 2012-03-07 | 2013-11-27 | 天通控股股份有限公司 | Stress-resistant nickel zinc ferrite with initial permeability of 120, and preparation method of stress-resistant nickel zinc ferrite |
| CN203465407U (en) * | 2013-10-12 | 2014-03-05 | 北京航空航天大学 | Soft-magnetic-material-magnetic-conductivity measurement experiment device based on oscilloscope and signal generator |
| RU2666685C1 (en) * | 2017-06-01 | 2018-09-11 | Общество с ограниченной ответственностью "ИнТек Техно" (ООО "ИнТек Техно") | Magnetic-liquid sealing |
| CN109727760A (en) * | 2018-12-29 | 2019-05-07 | 东莞中子科学中心 | Ultra-wideband non-invasive current measuring instrument and preparation method thereof |
| CN109781831A (en) * | 2019-03-08 | 2019-05-21 | 苏州科技大学 | A method for measuring high-frequency permeability of soft magnetic films |
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