Performance detection system and performance detection method for composite magnetic steel

Abstract

The invention discloses a performance detection system and a performance detection method for composite magnetic steel. In the performance detection system, a coil clamp is horizontally arranged right above the composite magnetic steel, a mobile carrier drives the composite magnetic steel to move at a first speed in a direction from a first area to a second area, and a flux meter is electrically connected with the coil clamp and is used for measuring a first magnetic flux of an overlapping part of the composite magnetic steel and the coil clamp in a moving process. The control unit is electrically connected with the fluxmeter and the moving carrier and used for obtaining a plurality of first magnetic fluxes in the moving process of the composite magnetic steel and controlling the moving carrier to stop when the difference value of the two first magnetic fluxes obtained in two adjacent time periods is larger than a first preset value so as to determine the boundary area of the first area and the second area. Therefore, the boundary area of the first area and the second area can be determined on the basis that the composite magnetic steel is not damaged, so that the zoning condition of the composite magnetic steel is determined, and whether the composite magnetic steel meets the design requirement in technology or not is detected.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of magnetic steel performance detection, and in particular to a performance detection system and a performance detection method for composite magnetic steel. Background Art

[0002] With the rapid development of the new energy vehicle industry, the application scope of permanent magnet synchronous motors in the field of new energy vehicles is becoming more and more extensive. In order to obtain higher performance motors, the requirements for the magnetic steel grades of motor rotors are getting higher and higher, and the cost and manufacturing difficulty of magnetic steel are also greatly increased. Usually, there are three most important parameters in the magnetic properties of magnetic steel. The first is remanence (Br), the second is intrinsic coercive force (Hcj), and the third is knee coercive force (Hk). Among them, Br is a characterization of the magnitude of the magnetic field strength that the magnetic steel can generate, Hcj is the magnetic field required when the magnetic steel is completely demagnetized, and Hk is the magnetic field strength when the magnetic steel begins to demagnetize. The higher the grade of the magnetic steel, the higher the anti-demagnetization ability and magnetic field strength.

[0003] In practical applications, in order to improve the motor's anti-demagnetization ability and electromagnetic performance, high-grade magnetic steel is usually selected, but the cost will also increase. The cost of magnetic steel accounts for about 20-30% of the overall material cost of the motor. Therefore, major manufacturers are now making technical reserves and adopting a compromise solution, using different grades of magnetic steel for splicing or infiltrating heavy rare earth elements on the basis of the original grade of magnetic steel, thereby reducing the heavy rare earth content and reducing costs. With the application of this solution, the problem that follows is how to detect whether the magnetic steel is perfectly partitioned according to the design requirements.

[0004] In the prior art, the partitioning condition of magnetic steel is often detected by slicing the magnetic steel. However, this method is likely to cause measurement errors due to insufficient slicing or difficulty in slicing the material, and the detection test speed is slow and the detection efficiency is low. Summary of the invention

[0005] The present invention provides a performance detection system and a performance detection method for a composite magnetic steel, which can determine the partitioning of the composite magnetic steel by determining the boundary area between a first area and a second area without damaging the composite magnetic steel, thereby detecting whether the composite magnetic steel meets the design requirements in terms of process.

[0006] In a first aspect, an embodiment of the present invention provides a performance detection system for a composite magnetic steel, the performance detection system comprising a coil fixture, a fluxmeter, a mobile carrier, and a control unit;

[0007] A composite magnetic steel is placed on the mobile carrier, the composite magnetic steel includes a first region and second regions located on both sides of the first region, and the magnetic properties of the first region are different from the magnetic properties of the second region;

[0008] The coil fixture is horizontally arranged directly above the composite magnetic steel, and the moving carrier drives the composite magnetic steel to move at a first speed in a direction from the first area to the second area;

[0009] The flux meter is electrically connected to the coil fixture and is used to measure the change in magnetic flux at the portion where the composite magnetic steel overlaps with the coil fixture during movement;

[0010] The control unit is electrically connected to the flux meter and the mobile carrier, respectively, and is used to determine multiple first magnetic fluxes based on the multiple magnetic flux changes during the movement of the composite magnetic steel, and when the difference between the two first magnetic fluxes determined in two adjacent time periods is greater than a first preset value, control the mobile carrier to stop, so as to determine the boundary area between the first area and the second area.

[0011] Optionally, the performance detection system further comprises a plurality of replacement coil fixtures;

[0012] The width of the cross section of the replacement coil fixture is less than the width of the cross section of the coil fixture;

[0013] The width of the cross section of different replacement coil fixtures is different;

[0014] The performance testing system is tested by replacing the replacement coil fixture.

[0015] Optionally, the performance detection system also includes a magnetic moment detection device and a demagnetization device;

[0016] The magnetic moment detection device is used to detect the magnetic moment of the composite magnetic steel;

[0017] The direction of the demagnetization magnetic field in the demagnetization device is opposite to the magnetization direction of the composite magnetic steel.

[0018] In a second aspect, an embodiment of the present invention further provides a performance detection method for a composite magnetic steel, the performance detection method being applied to any performance detection device described in the first aspect, the performance detection method comprising:

[0019] Acquiring multiple magnetic flux changes during the movement of the composite magnetic steel;

[0020] A plurality of first magnetic fluxes are determined according to the magnetic flux variation. When a difference between two first magnetic fluxes determined in two adjacent time periods is greater than the first preset value, the mobile vehicle is controlled to stop to determine a boundary area between the first area and the second area.

[0021] Optionally, the performance detection system further comprises a plurality of replacement coil fixtures; the width of the cross section of the replacement coil fixture is smaller than the width of the cross section of the first coil fixture; the widths of the cross sections of different replacement coil fixtures are different;

[0022] The performance testing method comprises:

[0023] After determining the boundary area between the first area and the second area, the method further includes:

[0024] S231, replacing the coil fixture with a replacement coil fixture having the largest cross-sectional width among the multiple replacement coil fixtures;

[0025] S232, controlling the mobile carrier to drive the composite magnetic steel to move within the boundary area at a first speed;

[0026] S233, determining a plurality of second magnetic fluxes of the overlapping portion of the replacement coil fixture during the movement of the composite magnetic steel, and when the difference between two second magnetic fluxes determined in two adjacent time periods is greater than the first preset value, controlling the mobile carrier to stop, so as to determine a first boundary area, wherein the range of the first boundary area is smaller than the boundary area;

[0027] S234, replace the remaining replacement coil fixtures in order of cross-sectional area from large to small, and repeat steps S232-S233 until the replacement coil fixture with the smallest cross-sectional area completes the test.

[0028] Optionally, the performance detection system further includes a magnetic moment detection device and a demagnetization device;

[0029] The magnetic moment detection device is used to detect the magnetic moment of the composite magnetic steel;

[0030] The direction of the demagnetization magnetic field in the demagnetization device is opposite to the magnetization direction of the composite magnetic steel;

[0031] The performance detection method comprises:

[0032] After determining the boundary area between the first area and the second area, the method further includes:

[0033] Obtaining the initial magnetic moment of the composite magnetic steel;

[0034] Placing the composite magnetic steel in the demagnetization device, controlling the magnetic field strength of the demagnetization magnetic field in the demagnetization device to increase sequentially with a second preset value as an increment, and obtaining a plurality of first magnetic moments of the composite magnetic steel in the process of the magnetic field strength of the demagnetization magnetic field increasing sequentially with the second preset value;

[0035] When the ratio of the change of the first magnetic moment to the initial magnetic moment to the initial magnetic moment is initially greater than a third preset value, it is determined that the knee coercive force of the composite magnetic steel is within a first range.

[0036] Optionally, after determining that the knee coercivity of the composite magnetic steel is within the first range, the method further includes:

[0037] Controlling the magnetic field strength of the demagnetization magnetic field in the demagnetization device to be based on the initial endpoint of the first range and to be increased in sequence with a fourth preset value as an increment, and obtaining a plurality of second magnetic moments of the composite magnetic steel during the process in which the magnetic field strength of the demagnetization magnetic field is increased with the fourth preset value, wherein the fourth preset value is less than the second preset value;

[0038] When the ratio of the change in the second magnetic moment to the initial magnetic moment to the initial magnetic moment is greater than a third preset value for the first time, the knee coercive force of the composite magnetic steel is determined.

[0039] Optionally, after determining the knee coercivity of the composite magnetic steel, the method further includes:

[0040] Controlling the magnetic field strength of the demagnetization magnetic field in the demagnetization device to increase sequentially with the value of the knee point coercive force as the basic value and with the fifth preset value as the increment, and obtaining a plurality of third magnetic moments of the composite magnetic steel in the process of the magnetic field strength of the demagnetization magnetic field increasing sequentially with the fifth preset value;

[0041] When the ratio of the change of the third magnetic moment to the initial magnetic moment to the initial magnetic moment is first greater than a sixth preset value, it is determined that the intrinsic coercive force of the composite magnetic steel is in the second range, and the sixth preset value is less than the third preset value.

[0042] Optionally, after determining that the intrinsic coercivity of the composite magnetic steel is within the second range, the method further includes:

[0043] Controlling the magnetic field strength of the demagnetization magnetic field in the demagnetization device to be based on the initial endpoint of the second range and to be increased in sequence with a seventh preset value as an increment, and obtaining a plurality of fourth magnetic moments of the composite magnetic steel during the process in which the magnetic field strength of the demagnetization magnetic field is increased with the seventh preset value, wherein the seventh preset value is less than the fifth preset value;

[0044] When the ratio of the change in the fourth magnetic moment to the initial magnetic moment to the initial magnetic moment is greater than a sixth preset value for the first time, the intrinsic coercive force of the composite magnetic steel is determined.

[0045] Optionally, after determining the intrinsic coercivity of the composite magnetic steel, the method further includes:

[0046] Determine the remanence of the composite magnetic steel according to the first formula and the second formula;

[0047] and fitting an intrinsic demagnetization curve of the composite magnetic steel according to the knee coercivity of the composite magnetic steel, the intrinsic coercivity of the composite magnetic steel, and the remanence of the composite magnetic steel;

[0048] The first formula includes:

[0049]

[0050] The second formula includes:

[0051]

[0052] Among them, μrec is the recoil magnetic permeability, Bdi is the intrinsic magnetic flux density, Pc is the magnetic permeability, L is the thickness of the composite magnetic steel, a is the length of the composite magnetic steel, and b is the width of the composite magnetic steel.

[0053] In an embodiment of the present invention, a performance detection system includes a first coil fixture, a fluxmeter, a mobile carrier, and a control unit. A composite magnetic steel is placed on the mobile carrier, and the composite magnetic steel includes a first area and a second area located on both sides of the first area. The magnetic properties of the first area are different from those of the second area. The coil fixture is horizontally arranged directly above the composite magnetic steel, and the mobile carrier drives the composite magnetic steel to move at a first speed in the direction from the first area to the second area. The fluxmeter is electrically connected to the coil fixture to measure the first magnetic flux of the overlapping part of the coil fixture during the movement of the composite magnetic steel. The control unit is electrically connected to the fluxmeter and the mobile carrier respectively to obtain multiple first magnetic fluxes during the movement of the composite magnetic steel, and when the difference between the two first magnetic fluxes obtained in two adjacent time periods is greater than the first preset value, the mobile carrier is controlled to stop to determine the boundary area between the first area and the second area. In this way, the boundary area between the first area and the second area can be determined without damaging the composite magnetic steel, thereby determining the partitioning of the composite magnetic steel and detecting whether the composite magnetic steel meets the design requirements in terms of process. The problem of not being able to conveniently detect the partition range after the composite magnetic steel is trial-produced in the product development stage is solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 It is a structural schematic diagram of a performance detection system for composite magnetic steel provided by an embodiment of the present invention;

[0055] Figure 2 It is a structural schematic diagram of another composite magnetic steel performance detection system provided by an embodiment of the present invention;

[0056] Figure 3 is a graph of an intrinsic demagnetization curve provided by an embodiment of the present invention;

[0057] Figure 4 It is a schematic flow chart of a performance testing method of a composite magnetic steel provided in an embodiment of the present invention;

[0058] Figure 5 It is a flow chart of another performance testing method of composite magnetic steel provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0059] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only 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 should fall within the scope of protection of the present invention.

[0060] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0061] Figure 1 is a structural schematic diagram of a performance detection system for composite magnetic steel provided by an embodiment of the present invention, see Figure 1 The performance detection system includes a coil fixture 10, a fluxmeter 20, a mobile carrier 30 and a control unit 40. A composite magnetic steel 50 is placed on the mobile carrier 30, and the composite magnetic steel 50 includes a first area 510 and a second area 520 located on both sides of the first area 510. The magnetic properties of the first area 510 are different from those of the second area 520. The coil fixture 10 is horizontally arranged directly above the composite magnetic steel 50, and the mobile carrier 30 drives the composite magnetic steel 50 to move at a first speed along the direction from the first area 510 to the second area 520. The fluxmeter 20 is electrically connected to the coil fixture 10, and is used to measure the first magnetic flux of the composite magnetic steel 50 overlapping with the coil fixture 10 during the movement of the composite magnetic steel 50. The control unit 40 is electrically connected to the fluxmeter 20 and the mobile carrier 30 respectively, and is used to obtain multiple first magnetic fluxes during the movement of the composite magnetic steel 50, and when the difference between the two first magnetic fluxes obtained in two adjacent time periods is greater than a first preset value, the mobile carrier 30 is controlled to stop to determine the boundary area between the first area 510 and the second area 520.

[0062] Specifically, Figure 1As shown, the composite magnetic steel 50 includes a first region 510 and a second region 520, wherein the second region 520 is located on both sides of the first region 510, and the magnetic properties of the first region 510 and the second region 520 are different. Exemplarily, the magnetic properties of the first region 510 are smaller than those of the second region 520, that is, the intrinsic coercivity and knee coercivity of the composite magnetic steel 50 in the first region 510 are both smaller than the intrinsic coercivity and knee coercivity of the composite magnetic steel 50 in the second region 520. It should be noted that the composite magnetic steel 50 can be formed by infiltrating heavy rare earth elements on both sides of a low-grade magnetic steel so that a high-grade magnetic steel is formed on both sides of the magnetic steel. In other words, the first region 510 is used as the main body, and the heavy rare earth elements are infiltrated in the second region 520, so that the magnetic properties of the first region 510 are smaller than those of the second region 520. It is understandable that the embodiment of the present invention does not limit the specific preparation method of the composite magnetic steel 50. In other embodiments, the composite magnetic steel 50 can be formed by splicing magnetic steels of different brands, and those skilled in the art can set it according to needs.

[0063] In the prior art, after the composite magnetic steel is prepared, the composite magnetic steel is usually sliced ​​to detect the partitioning of the composite magnetic steel. However, the slicing method may result in insufficient slicing, or the material may be too hard to slice, which may cause measurement errors. In addition, the detection test speed is slow and the detection efficiency is low.

[0064] To this end, an embodiment of the present invention provides a performance detection system, which includes a coil fixture 10, a flux meter 20, a mobile carrier 30, and a control unit 40. The coil fixture 10 is horizontally arranged directly above the composite magnetic steel 50. When the composite magnetic steel 50 passes under the coil fixture 10, the flux meter 20 can detect the change in magnetic flux of the overlapping portion of the composite magnetic steel 50 and the coil fixture 10 during the movement of the composite magnetic steel 50. The control unit 40 is electrically connected to the flux meter 20, and is used to obtain multiple magnetic flux changes of the composite magnetic steel 50 during the movement, and determine multiple first magnetic fluxes of the composite magnetic steel 50 during the movement according to the flux calculation formula, wherein the flux calculation formula includes: first magnetic flux = flux meter constant × magnetic flux change / number of turns of the coil fixture.

[0065] In addition, the composite magnetic steel 50 is fixed on the mobile carrier 30, and the mobile carrier 30 can drive the composite magnetic steel 50 to move at a first speed along the direction from the first area 510 to the second area 520, so that the composite magnetic steel 50 passes under the coil fixture 10, which is convenient for the flux meter 20 to measure the magnetic flux change of each part of the composite magnetic steel 50. It can be understood that according to the measurement principle of the coil fixture 10, the width of each part of the composite magnetic steel 50 corresponding to the magnetic flux change is similar to the width of the coil fixture 10. The control unit 40 is also electrically connected to the mobile carrier 30. After determining multiple first magnetic fluxes of the composite magnetic steel 50 during the movement process, it will compare whether the difference between the two first magnetic fluxes determined at two adjacent time moments is greater than the first preset value according to the time sequence of obtaining the magnetic flux (that is, the order of determining the first magnetic flux). If the difference between the two first magnetic fluxes determined at two adjacent time periods is less than or equal to the first preset value, it means that the coil clamp 10 overlaps with the first area 510 or the second area 520 of the composite magnetic steel 50 (the magnetic properties of the same area in the composite magnetic steel 50 are similar). At this time, the boundary area between the first area 510 and the second area 520 is not determined, and the mobile carrier 30 continues to be controlled to move. If the difference between the two first magnetic fluxes determined in two adjacent time periods is greater than the first preset value, it means that the magnetic properties of the two adjacent parts of the composite magnetic steel 50 corresponding to the two first magnetic fluxes determined at this time vary greatly, and the mobile carrier 30 is controlled to stop. When the mobile carrier 30 stops, the overlapping area of ​​the coil fixture 10 and the composite magnetic steel 50 is the boundary area between the first area 510 and the second area 520. In this way, the boundary area between the first area 510 and the second area 520 can be accurately defined without slicing and analyzing the composite magnetic steel, and the partitioning of the composite magnetic steel 50 can be determined, which is convenient for subsequent detection of whether the composite magnetic steel 50 meets the design requirements in terms of process (comparison of the detected partitioning situation with the expected partitioning situation), and solves the problem of not being able to conveniently detect the partition range after the composite magnetic steel is trial-produced in the product development stage.

[0066] In summary, the performance detection system in the embodiment of the present invention includes a first coil fixture, a fluxmeter, a mobile carrier and a control unit. A composite magnetic steel is placed on the mobile carrier, and the composite magnetic steel includes a first area and a second area located on both sides of the first area. The magnetic properties of the first area are different from those of the second area. The coil fixture is horizontally arranged directly above the composite magnetic steel, and the mobile carrier drives the composite magnetic steel to move at a first speed in the direction from the first area to the second area. The fluxmeter is electrically connected to the coil fixture to measure the first magnetic flux of the overlapping part of the coil fixture during the movement of the composite magnetic steel. The control unit is electrically connected to the fluxmeter and the mobile carrier respectively, and is used to obtain multiple first magnetic fluxes during the movement of the composite magnetic steel, and when the difference between the two first magnetic fluxes obtained in two adjacent time periods is greater than the first preset value, the mobile carrier is controlled to stop to determine the boundary area between the first area and the second area. In this way, the boundary area between the first area and the second area can be determined without damaging the composite magnetic steel, thereby determining the partitioning of the composite magnetic steel, and detecting whether the composite magnetic steel meets the design requirements in terms of process. It solves the problem that the partition range cannot be conveniently detected after the composite magnetic steel is trial-produced in the product development stage.

[0067] Optionally, based on the above embodiment, continue to refer to Figure 1 The performance testing system further includes a plurality of replacement coil fixtures (not shown in the figure). The width of the cross section of the replacement coil fixture is smaller than the width of the cross section of the coil fixture 10. The widths of the cross sections of different replacement coil fixtures are different, and the performance testing system performs the test by replacing the replacement coil fixtures.

[0068] Specifically, according to the measurement principle of the coil fixture 10, the width of each part of the composite magnetic steel 50 corresponding to the change in magnetic flux is similar to the width of the coil fixture 10. Therefore, the accuracy of the boundary area detection is related to the width of the cross section of the coil fixture 10. The narrower the width of the cross section of the coil fixture 10, the more accurate the boundary area detection. Furthermore, in an embodiment of the present invention, after the boundary area is roughly determined by the coil fixture 10 with a wider cross section, the range of the boundary area can also be narrowed by replacing the replacement coil fixture to obtain a more accurate first boundary area. Exemplarily, the performance detection system also includes multiple replacement coil fixtures, and the width of the cross section of different replacement coil fixtures is different. After determining the boundary area, the coil fixture 10 is replaced with a replacement coil fixture with the largest cross-sectional width among the multiple replacement coil fixtures. Afterwards, the control unit 40 controls the mobile carrier 30 to drive the composite magnetic steel 50 to move at a first speed within the range of the boundary area, in the direction from the first area 510 to the second area 520, to obtain the magnetic flux change of the composite magnetic steel 50 in the boundary area where it overlaps with the replacement coil fixture, and then determines the multiple second magnetic fluxes of the composite magnetic steel 50 in the boundary area where it intersects with the replacement coil according to the magnetic flux calculation formula, and determines whether the difference between the two second magnetic fluxes determined in two adjacent time periods in the process is greater than the first preset value. If the difference is less than or equal to the first preset value, the mobile carrier 30 is controlled to continue working. If the difference is greater than the first preset value, the mobile carrier 30 is controlled to stop. When the mobile carrier 30 stops, the area of ​​the composite magnetic steel 50 that overlaps with the replacement coil fixture is determined as the first boundary area, wherein the first boundary area is located in the boundary area, that is, the range of the first boundary area is smaller than the range of the boundary area. Finally, replace the remaining replacement coil fixtures in order of their cross-sectional areas from large to small, and repeat the above steps, such as replacing the previous replacement coil fixture with the replacement coil fixture with the largest cross-sectional width among the remaining replacement coil fixtures, and test within the first boundary range. Finally, test to obtain the second boundary range, and the second boundary range is within the first boundary range, ... until the last replacement coil fixture (with the smallest cross-sectional area) completes the test to obtain the Nth boundary range. In this way, the test accuracy of the boundary range is further improved.

[0069] Optional, Figure 2 Schematic diagram of another composite magnetic steel performance detection system provided by an embodiment of the present invention. Figure 2 The performance detection system further includes a magnetic moment detection device 60 and a demagnetization device 70. The magnetic moment detection device 60 is used to detect the magnetic moment of the composite magnetic steel. The direction of the demagnetization magnetic field in the demagnetization device 70 is opposite to the magnetization direction of the composite magnetic steel.

[0070] Specifically, the composite magnetic steel is placed in the magnetic moment detection device 60, and the magnetic moment detection device 60 can detect the magnetic moment of the composite magnetic steel (which can be obtained according to the magnetic moment detection device and the magnetic moment calculation formula), and the direction of the demagnetization magnetic field in the demagnetization device 70 is opposite to the magnetization direction of the composite magnetic steel. The knee coercive force and the intrinsic coercive force of the composite magnetic steel can be calculated by the cooperation between the magnetic moment detection device 60 and the demagnetization device 70.

[0071] Exemplarily, the initial magnetic moment of the composite magnetic steel is obtained, and then the composite magnetic steel is placed in the demagnetization device 70. The direction of the demagnetization magnetic field in the demagnetization device 70 is opposite to the magnetization direction of the composite magnetic steel. By controlling the magnetic field strength of the demagnetization magnetic field in the demagnetization device, the degree of demagnetization of the composite magnetic steel can be controlled. Then, the magnetic field strength of the demagnetization magnetic field is controlled by the control unit 40 to be based on 0, and to increase in sequence with the second preset value as the increment. After each increment of the magnetic field strength of the demagnetization device, the magnetic moment detection device 60 determines the multiple first magnetic moments of the composite magnetic steel after each increment. When the ratio of the change in the first magnetic moment to the initial magnetic moment to the initial magnetic moment is greater than the third preset value for the first time, it is determined that the knee coercive force of the composite magnetic steel is in the first range. Among them, the second preset value is the magnetic field strength value, which can be set by those skilled in the art as needed. The third preset value can be 4%. For example, the magnetic field strength of the demagnetization magnetic field of the demagnetization device 70 after the first increase is H1, the magnetic field strength after the second increase is H2, and ... the magnetic field strength after the i-th increase is Hi. If the ratio of the difference (change) between the first magnetic moment of the composite magnetic steel and the initial magnetic moment to the initial magnetic moment is less than 4% when the magnetic field strength after the demagnetization device 70 is increased for the fifth time is H5, and the ratio of the difference (change) between the first magnetic moment of the composite magnetic steel and the initial magnetic moment to the initial magnetic moment is greater than 4% when the magnetic field strength after the demagnetization device 70 is increased for the sixth time is H6, it indicates that the knee coercive force Hk of the composite magnetic steel is between H5 and H6, that is, the first range is (H5, H6).

[0072] It should be noted that after determining that the knee coercivity of the composite magnetic steel is within the first range, it is necessary to further accurately determine the knee coercivity of the composite magnetic steel. Exemplarily, after determining that the knee coercivity of the composite magnetic steel is within the first range, the magnetic field strength of the demagnetization magnetic field in the demagnetization device 70 is controlled to be based on the initial endpoint (e.g., H5) of the first range, and to increase in sequence with the fourth preset value as the increment, and obtain multiple second magnetic moments of the composite magnetic steel during the process of the magnetic field strength of the demagnetization magnetic field increasing with the fourth preset value, wherein the fourth preset value is less than the second preset value, and when the ratio of the change in the second magnetic moment to the initial magnetic moment to the initial magnetic moment is greater than the third preset value for the first time, the knee coercivity of the composite magnetic steel is determined. For example, on the basis that the magnetic field strength after the fifth increase of the demagnetization device 70 is H5, the magnetic field strength after the first increase of the fourth preset value is H51, the magnetic field strength after the second increase of the fourth preset value is H52, ... the magnetic field strength after the i-th increase of the fourth preset value is H5i. It should be noted that H5i is less than H6. Furthermore, if the magnetic field strength after the demagnetization device 70 increases the fourth preset value for the fifth time is H55, and the ratio of the difference (change) between the first magnetic moment of the composite magnetic steel and the initial magnetic moment to the initial magnetic moment is greater than 4% for the first time, it indicates that the knee coercive force Hk of the composite magnetic steel is H55.

[0073] In addition, after determining the knee coercive force Hk of the composite magnetic steel, the magnetic field strength of the demagnetization magnetic field in the demagnetization device 70 is controlled to be based on the value of the knee coercive force Hk, and to increase in sequence with the fifth preset value as the increment, and obtain multiple third magnetic moments of the composite magnetic steel in the process of the magnetic field strength of the demagnetization magnetic field increasing in sequence with the fifth preset value. When the difference (variation) between the third magnetic moment and the initial magnetic moment and the ratio of the initial magnetic moment are first greater than the sixth preset value, it is determined that the intrinsic coercive force Hcj of the composite magnetic steel is in the second range, and the sixth preset value is less than the third preset value. Among them, the fifth preset value is a magnetic field strength value, which can be set by those skilled in the art as needed, and the sixth preset value can be 1%. For example, the demagnetization magnetic field of the demagnetization device 70 is based on the knee coercive force Hk, and the magnetic field strength after the first increase of the fifth preset value is C1, the magnetic field strength after the second increase of the fifth preset value is C2, ... The magnetic field strength after the i-th increase of the fifth preset value is Ci. Furthermore, if the ratio of the difference (change) between the second magnetic moment of the composite magnetic steel and the initial magnetic moment to the initial magnetic moment is less than 1% when the magnetic field strength after the demagnetization device 70 increases the fifth preset value for the first time is C5, and the ratio of the difference (change) between the second magnetic moment of the composite magnetic steel and the initial magnetic moment to the initial magnetic moment is greater than 1% when the magnetic field strength after the demagnetization device 70 increases the fifth preset value for the sixth time is C6, then it indicates that the intrinsic coercive force Hcj of the composite magnetic steel is between C5 and C6, that is, the second range is (C5, C6).

[0074] It should be noted that after determining that the intrinsic coercivity Hcj of the composite magnetic steel is in the second range, it is necessary to further accurately determine the intrinsic coercivity Hcj of the composite magnetic steel. Exemplarily, after determining that the intrinsic coercivity of the composite magnetic steel is in the second range, the magnetic field strength of the demagnetization magnetic field in the demagnetization device 70 is controlled to be based on the initial endpoint (e.g., C5) of the second range, and to increase in sequence with the seventh preset value as the increment, and obtain a plurality of fourth magnetic moments of the composite magnetic steel in the process of the magnetic field strength of the demagnetization magnetic field increasing with the seventh preset value, wherein the seventh preset value is less than the fifth preset value, and when the ratio of the change amount of the fourth magnetic moment to the initial magnetic moment to the initial magnetic moment is greater than the sixth preset value for the first time, the intrinsic coercivity Hcj of the composite magnetic steel is determined. For example, on the basis that the magnetic field strength after the demagnetization device 70 increases the fifth preset value for the fifth time is C5, the magnetic field strength after the seventh preset value is increased for the first time is C51, the magnetic field strength after the seventh preset value is increased for the second time is C52, ... the magnetic field strength after the seventh preset value is increased for the i-th time is C5i. It should be noted that C5i is smaller than C6. Furthermore, if the magnetic field strength after the demagnetization device 70 increases the seventh preset value for the fifth time is C55, and the ratio of the difference (variation) between the fourth magnetic moment of the composite magnetic steel and the initial magnetic moment to the initial magnetic moment is greater than 1% for the first time, it indicates that the intrinsic coercive force Hcj of the composite magnetic steel is C55.

[0075] On the basis of the above, Figure 3 is a graph of an intrinsic demagnetization curve provided by an embodiment of the present invention. Figure 3 , the embodiment of the present invention also determines the remanence of the composite magnetic steel by the first formula and the second formula. The first formula includes Where μrec is the recoil permeability, Bdi is the intrinsic magnetic flux density, and Pc is the magnetic permeability. The second formula includes Wherein, L is the thickness of the composite magnetic steel, a is the length of the composite magnetic steel, and b is the width of the composite magnetic steel. After calculating the remanence of the composite magnetic steel, the intrinsic demagnetization curve of the composite magnetic steel is fitted according to the knee coercivity Hk of the composite magnetic steel, the intrinsic coercivity Hcj of the composite magnetic steel, and the remanence of the composite magnetic steel. The intrinsic demagnetization curve of the composite magnetic steel is compared with the intrinsic demagnetization curve of the basic grade (single grade) magnetic steel, so as to facilitate a more comprehensive explanation of the advantages and disadvantages of the composite magnetic steel and the single grade magnetic steel from the perspective of magnetic properties, which is conducive to the analysis and expansion of the application scenarios of the composite magnetic steel.

[0076] Based on the same inventive concept, an embodiment of the present invention also provides a performance testing method for composite magnetic steel. Figure 4 It is a schematic flow chart of a performance testing method of a composite magnetic steel provided in an embodiment of the present invention.

[0077] See also Figure 4 , the performance testing method includes:

[0078] S110, obtaining multiple magnetic flux changes during the movement of the composite magnetic steel.

[0079] The coil fixture is horizontally arranged directly above the composite magnetic steel, and the composite magnetic steel is fixed on the moving carrier. The moving carrier can drive the composite magnetic steel to move in the direction from the first area to the second area at a first speed, so that the composite magnetic steel passes under the coil fixture. When the composite magnetic steel passes under the coil fixture, the flux meter can detect the change in magnetic flux of the overlapping part of the composite magnetic steel and the coil fixture during the movement of the composite magnetic steel. The control unit is electrically connected to the flux meter to obtain multiple changes in magnetic flux of the composite magnetic steel during the movement.

[0080] S120, determining a plurality of first magnetic fluxes according to the magnetic flux variation, and when a difference between two first magnetic fluxes determined in two adjacent time periods is greater than a first preset value, controlling the mobile carrier to stop, so as to determine a boundary area between the first area and the second area.

[0081] After obtaining multiple magnetic flux changes of the composite magnetic steel during the movement process, the control unit determines multiple first magnetic fluxes of the composite magnetic steel during the movement process according to the magnetic flux calculation formula, wherein the magnetic flux calculation formula includes: first magnetic flux = fluxmeter constant × magnetic flux change / number of turns of the coil fixture. After determining multiple first magnetic fluxes of the composite magnetic steel during the movement process, the difference between the two first magnetic fluxes determined at two adjacent time moments will be compared according to the time sequence of the magnetic flux acquisition (i.e., the determination sequence of the first magnetic flux) to see whether it is greater than the first preset value. If the difference between the two first magnetic fluxes determined at two adjacent time periods is less than or equal to the first preset value, it means that the coil fixture overlaps with the first area or the second area of ​​the composite magnetic steel (the magnetic properties of the same area in the composite magnetic steel are similar). At this time, the boundary area between the first area and the second area is not determined, and the mobile carrier continues to be controlled to move. If the difference between the two first magnetic fluxes determined in two adjacent time periods is greater than the first preset value, it means that the magnetic properties of the two adjacent parts of the composite magnetic steel corresponding to the two first magnetic fluxes determined at this time vary greatly, and the mobile carrier is controlled to stop. When the mobile carrier stops, the overlapping area between the coil fixture and the composite magnetic steel is the boundary area between the first area and the second area. In this way, the boundary area between the first area and the second area can be accurately defined without slicing and analyzing the composite magnetic steel, and the partitioning of the composite magnetic steel can be determined, which is convenient for subsequent detection of whether the composite magnetic steel meets the design requirements in terms of process (comparison of the detected partitioning situation with the expected partitioning situation), and solves the problem of not being able to conveniently detect the partition range after the composite magnetic steel is trial-produced in the product development stage.

[0082] In summary, the embodiment of the present invention obtains multiple magnetic flux changes during the movement of the composite magnetic steel, determines multiple first magnetic fluxes according to the magnetic flux changes, and controls the mobile carrier to stop when the difference between the two first magnetic fluxes determined in two adjacent time periods is greater than a first preset value, so as to determine the boundary area between the first area and the second area. In this way, the boundary area between the first area and the second area can be determined without damaging the composite magnetic steel, thereby determining the partitioning of the composite magnetic steel and detecting whether the composite magnetic steel meets the design requirements in terms of process. This solves the problem of not being able to conveniently detect the partition range after the composite magnetic steel is trial-produced in the product development stage.

[0083] Optional, Figure 5 FIG. 1 is a flow chart of another performance testing method of composite magnetic steel provided by an embodiment of the present invention. Figure 5 , the performance testing method includes:

[0084] S210, obtaining multiple magnetic flux changes during the movement of the composite magnetic steel.

[0085] S220, determining a plurality of first magnetic fluxes according to the magnetic flux variation, and when a difference between two first magnetic fluxes determined in two adjacent time periods is greater than a first preset value, controlling the mobile carrier to stop, so as to determine a boundary area between the first area and the second area.

[0086] S231, replacing the coil fixture with a replacement coil fixture having the largest cross-sectional width among multiple replacement coil fixtures.

[0087] Specifically, according to the measurement principle of the coil fixture, the width of each part of the composite magnetic steel corresponding to the change in magnetic flux is similar to the width of the coil fixture. Therefore, the accuracy of the boundary area detection is related to the width of the cross section of the coil fixture. The narrower the width of the cross section of the coil fixture, the more accurate the boundary area detection. Furthermore, in an embodiment of the present invention, after the boundary area is roughly determined by a coil fixture with a wider cross section, the range of the boundary area can be narrowed by replacing the coil fixture to obtain a more accurate first boundary area. Exemplarily, after determining the boundary area, the coil fixture is replaced with a replacement coil fixture with the largest cross-sectional width among multiple replacement coil fixtures.

[0088] S232, controlling the mobile carrier to drive the composite magnetic steel to move at a first speed within the boundary area.

[0089] After the replacement coil fixture is replaced, the control unit controls the mobile carrier to drive the composite magnetic steel to move at a first speed within the boundary area, in a direction from the first area to the second area. It is understandable that the embodiment of the present invention is exemplified by taking the movement speed of the mobile carrier before and after the replacement coil fixture as the same as an example, but it is not limited to this. In other embodiments, the speeds of the two can also be different.

[0090] S233, determining a plurality of second magnetic fluxes overlapping with the replacement coil fixture during the movement of the composite magnetic steel, and when the difference between two second magnetic fluxes determined in two adjacent time periods is greater than a first preset value, controlling the mobile carrier to stop to determine a first boundary area.

[0091] The change in magnetic flux of the composite magnetic steel in the overlapping part with the replacement coil fixture in the boundary area is obtained, and then a plurality of second magnetic fluxes of the composite magnetic steel in the intersection part with the replacement coil in the boundary area are determined according to the magnetic flux calculation formula, and it is judged whether the difference between the two second magnetic fluxes determined in two adjacent time periods in the process is greater than a first preset value. If the difference is less than or equal to the first preset value, the mobile carrier 30 is controlled to continue working. If the difference is greater than the first preset value, the mobile carrier is controlled to stop. When the mobile carrier is stopped, the area of ​​the composite magnetic steel overlapping with the replacement coil fixture is determined as the first boundary area, wherein the first boundary area is located in the boundary area, that is, the range of the first boundary area is smaller than the range of the boundary area.

[0092] S234, replace the remaining replacement coil fixtures in order of their cross-sectional areas from large to small, and repeat steps S232-S233 until the replacement coil fixture with the smallest cross-sectional area completes the test.

[0093] Finally, replace the remaining replacement coil fixtures in order of their cross-sectional areas from large to small, repeat the above steps S232-S233, such as replacing the previous replacement coil fixture with the replacement coil fixture with the largest cross-sectional width among the remaining replacement coil fixtures, and perform tests within the first boundary range. Finally, test to obtain the second boundary range, and the second boundary range is within the first boundary range, ... until the last replacement coil fixture (with the smallest cross-sectional area) completes the test to obtain the Nth boundary range. In this way, the test accuracy of the boundary range is further improved.

[0094] S240, obtaining the initial magnetic moment of the composite magnetic steel, placing the composite magnetic steel in a demagnetization device, controlling the magnetic field strength of the demagnetization magnetic field in the demagnetization device to increase sequentially with a second preset value, and obtaining multiple first magnetic moments of the composite magnetic steel in the process of the magnetic field strength of the demagnetization magnetic field increasing sequentially with the second preset value, and when the ratio of the change in the first magnetic moment to the initial magnetic moment to the initial magnetic moment is first greater than a third preset value, determining that the knee coercive force of the composite magnetic steel is in the first range.

[0095] The initial magnetic moment of the composite magnetic steel is obtained, and then the composite magnetic steel is placed in a demagnetization device. The direction of the demagnetization magnetic field in the demagnetization device is opposite to the magnetization direction of the composite magnetic steel. By controlling the magnetic field strength of the demagnetization magnetic field in the demagnetization device, the degree of demagnetization of the composite magnetic steel can be controlled. Then, the magnetic field strength of the demagnetization magnetic field is controlled by the control unit based on 0, and increases in sequence with the second preset value as the increment. After each increment of the magnetic field strength of the demagnetization device, the multiple first magnetic moments of the composite magnetic steel after each increment are determined by the magnetic moment detection device. When the ratio of the change in the first magnetic moment to the initial magnetic moment to the initial magnetic moment is greater than the third preset value for the first time, it is determined that the knee coercive force of the composite magnetic steel is in the first range. Among them, the second preset value is the magnetic field strength value, which can be set by technicians in this field as needed, and the third preset value can be 4%. For example, the magnetic field strength of the demagnetization magnetic field of the demagnetization device after the first increase is H1, the magnetic field strength after the second increase is H2, and... the magnetic field strength after the i-th increase is Hi. If the ratio of the difference (change) between the first magnetic moment of the composite magnetic steel and the initial magnetic moment to the initial magnetic moment is less than 4% when the magnetic field strength after the demagnetization device 70 is increased for the fifth time is H5, and the ratio of the difference (change) between the first magnetic moment of the composite magnetic steel and the initial magnetic moment to the initial magnetic moment is greater than 4% when the magnetic field strength after the demagnetization device 70 is increased for the sixth time is H6, it indicates that the knee coercive force of the composite magnetic steel is between H5 and H6, that is, the first range is (H5, H6).

[0096] It should be noted that after determining that the knee coercivity of the composite magnetic steel is within the first range, it is necessary to further accurately determine the knee coercivity of the composite magnetic steel. Exemplarily, after determining that the knee coercivity of the composite magnetic steel is within the first range, the magnetic field strength of the demagnetization magnetic field in the demagnetization device is controlled to be based on the initial endpoint (e.g., H5) of the first range, and to increase in sequence with the fourth preset value as the increment, and obtain multiple second magnetic moments of the composite magnetic steel during the process of the magnetic field strength of the demagnetization magnetic field increasing with the fourth preset value, wherein the fourth preset value is less than the second preset value, and when the ratio of the change in the second magnetic moment to the initial magnetic moment to the initial magnetic moment is first greater than the third preset value, the knee coercivity of the composite magnetic steel is determined. For example, on the basis that the magnetic field strength after the fifth increase of the demagnetization device is H5, the magnetic field strength after the first increase of the fourth preset value is H51, the magnetic field strength after the second increase of the fourth preset value is H52, ... the magnetic field strength after the i-th increase of the fourth preset value is H5i. It should be noted that H5i is less than H6. Furthermore, if the magnetic field strength is H55 after the demagnetization device increases the fourth preset value for the fifth time, and the ratio of the difference (change) between the first magnetic moment of the composite magnetic steel and the initial magnetic moment to the initial magnetic moment is greater than 4% for the first time, it indicates that the knee coercive force of the composite magnetic steel is H55.

[0097] S250, controlling the magnetic field strength of the demagnetization magnetic field in the demagnetization device to take the value of the knee coercive force as the base value, and increasing it sequentially with the fifth preset value as the increment value, and obtaining multiple third magnetic moments of the composite magnetic steel in the process of the magnetic field strength of the demagnetization magnetic field increasing sequentially with the fifth preset value, and when the ratio of the change of the third magnetic moment to the initial magnetic moment to the initial magnetic moment is greater than the sixth preset value for the first time, determining that the intrinsic coercive force of the composite magnetic steel is in the second range.

[0098] Specifically, the fifth preset value is a magnetic field strength value, which can be set by those skilled in the art as needed. The sixth preset value can be 1%. For example, assuming that the demagnetization magnetic field of the demagnetization device 70 is based on the knee coercive force, the magnetic field strength after the first increase of the fifth preset value is C1, the magnetic field strength after the second increase of the fifth preset value is C2, and ... the magnetic field strength after the i-th increase of the fifth preset value is Ci. Furthermore, if the magnetic field strength after the demagnetization device increases the fifth preset value for the first time is C5, the ratio of the difference (variation) between the second magnetic moment of the composite magnetic steel and the initial magnetic moment to the initial magnetic moment is less than 1%, and when the magnetic field strength after the demagnetization device increases the fifth preset value for the sixth time is C6, the ratio of the difference (variation) between the second magnetic moment of the composite magnetic steel and the initial magnetic moment to the initial magnetic moment is greater than 1%, it indicates that the intrinsic coercive force of the composite magnetic steel is between C5 and C6, that is, the second range is (C5, C6).

[0099] It should be noted that after determining that the intrinsic coercivity of the composite magnetic steel is in the second range, it is necessary to further accurately determine the intrinsic coercivity of the composite magnetic steel. Exemplarily, after determining that the intrinsic coercivity of the composite magnetic steel is in the second range, the magnetic field strength of the demagnetization magnetic field in the demagnetization device is controlled to be based on the initial endpoint (e.g., C5) of the second range, and to increase in sequence with the seventh preset value as the increment, and obtain multiple fourth magnetic moments of the composite magnetic steel during the process of the magnetic field strength of the demagnetization magnetic field increasing with the seventh preset value, wherein the seventh preset value is less than the fifth preset value, and when the ratio of the change amount of the fourth magnetic moment to the initial magnetic moment to the initial magnetic moment is greater than the sixth preset value for the first time, the intrinsic coercivity of the composite magnetic steel is determined. For example, on the basis that the magnetic field strength after the demagnetization device increases the fifth preset value for the fifth time is C5, the magnetic field strength after the seventh preset value is increased for the first time is C51, the magnetic field strength after the seventh preset value is increased for the second time is C52, ... the magnetic field strength after the seventh preset value is increased for the i-th time is C5i. It should be noted that C5i is less than C6. Furthermore, if the magnetic field strength is C55 after the demagnetization device increases the seventh preset value for the fifth time, and the ratio of the difference (change) between the fourth magnetic moment of the composite magnetic steel and the initial magnetic moment to the initial magnetic moment is greater than 1% for the first time, it indicates that the intrinsic coercive force of the composite magnetic steel is C55.

[0100] S260, determining the remanence of the composite magnetic steel according to the first formula and the second formula, and fitting the intrinsic demagnetization curve of the composite magnetic steel according to the knee coercivity of the composite magnetic steel, the intrinsic coercivity of the composite magnetic steel, and the remanence of the composite magnetic steel.

[0101] Specifically, the first formula includes Where μrec is the recoil permeability, Bdi is the intrinsic magnetic flux density, and Pc is the magnetic permeability. The second formula includes Wherein, L is the thickness of the composite magnetic steel, a is the length of the composite magnetic steel, and b is the width of the composite magnetic steel. After calculating the remanence of the composite magnetic steel, the intrinsic demagnetization curve of the composite magnetic steel is fitted according to the knee coercivity of the composite magnetic steel, the intrinsic coercivity of the composite magnetic steel, and the remanence of the composite magnetic steel. The intrinsic demagnetization curve of the composite magnetic steel is compared with the intrinsic demagnetization curve of the basic grade (single grade) magnetic steel, so as to facilitate a more comprehensive explanation of the advantages and disadvantages of the composite magnetic steel and the single grade magnetic steel from the perspective of magnetic properties, which is conducive to the analysis and expansion of the application scenarios of the composite magnetic steel.

[0102] In summary, the embodiment of the present invention obtains the knee coercivity and the intrinsic coercivity of the composite magnetic steel by calculation, and determines the remanence of the composite magnetic steel according to the first formula and the second formula, and finally fits the intrinsic demagnetization curve of the composite magnetic steel by the determined knee coercivity, intrinsic coercivity and remanence of the composite magnetic steel. In this way, the intrinsic demagnetization curve of the composite magnetic steel is compared with the intrinsic demagnetization curve of the basic grade (single grade) magnetic steel, so as to facilitate a more comprehensive explanation of the advantages and disadvantages of the composite magnetic steel and the single grade magnetic steel from the perspective of magnetic properties, which is conducive to the analysis and expansion of the application scenarios of the composite magnetic steel.

[0103] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A performance detection system for composite magnetic steel, characterized in that: include: The performance detection system includes a coil fixture, a flux meter, a mobile carrier and a control unit; A composite magnetic steel is placed on the mobile carrier, the composite magnetic steel includes a first region and second regions located on both sides of the first region, and the magnetic properties of the first region are different from the magnetic properties of the second region; The coil fixture is horizontally arranged directly above the composite magnetic steel, and the moving carrier drives the composite magnetic steel to move at a first speed in a direction from the first area to the second area; The flux meter is electrically connected to the coil fixture and is used to measure the change in magnetic flux at the portion where the composite magnetic steel overlaps with the coil fixture during movement; The control unit is electrically connected to the flux meter and the mobile carrier, respectively, and is used to determine multiple first magnetic fluxes based on the multiple magnetic flux changes during the movement of the composite magnetic steel, and when the difference between the two first magnetic fluxes determined in two adjacent time periods is greater than a first preset value, control the mobile carrier to stop, so as to determine the boundary area between the first area and the second area.

2. The performance detection system according to claim 1, characterized in that: The performance testing system also includes a plurality of replacement coil fixtures; The width of the cross section of the replacement coil fixture is less than the width of the cross section of the coil fixture; The width of the cross section of different replacement coil fixtures is different; The performance testing system is tested by replacing the replacement coil fixture.

3. The performance detection system according to claim 1, characterized in that: The performance detection system also includes a magnetic moment detection device and a demagnetization device; The magnetic moment detection device is used to detect the magnetic moment of the composite magnetic steel; The direction of the demagnetization magnetic field in the demagnetization device is opposite to the magnetization direction of the composite magnetic steel.

4. A performance detection method for composite magnetic steel, applied to the performance detection system according to any one of claims 1 to 3, characterized in that: The performance detection method comprises: Acquiring multiple magnetic flux changes during the movement of the composite magnetic steel; A plurality of first magnetic fluxes are determined according to the magnetic flux variation. When a difference between two first magnetic fluxes determined in two adjacent time periods is greater than the first preset value, the mobile vehicle is controlled to stop to determine a boundary area between the first area and the second area.

5. The performance detection method according to claim 4, characterized in that: The performance detection system further comprises a plurality of replacement coil fixtures; the width of the cross section of the replacement coil fixture is smaller than the width of the cross section of the first coil fixture; The width of the cross section of different replacement coil fixtures is different; The performance testing method comprises: After determining the boundary area between the first area and the second area, the method further includes: S231, replacing the coil fixture with a replacement coil fixture having the largest cross-sectional width among the multiple replacement coil fixtures; S232, controlling the mobile carrier to drive the composite magnetic steel to move within the boundary area at a first speed; S233, determining a plurality of second magnetic fluxes of the overlapping portion of the replacement coil fixture during the movement of the composite magnetic steel, and when the difference between two second magnetic fluxes determined in two adjacent time periods is greater than the first preset value, controlling the mobile carrier to stop, so as to determine a first boundary area, wherein the range of the first boundary area is smaller than the boundary area; S234, replace the remaining replacement coil fixtures in order of cross-sectional area from large to small, and repeat steps S232-S233 until the replacement coil fixture with the smallest cross-sectional area completes the test.

6. The performance detection method according to claim 4, characterized in that: The performance detection system also includes a magnetic moment detection device and a demagnetization device; The magnetic moment detection device is used to detect the magnetic moment of the composite magnetic steel; The direction of the demagnetization magnetic field in the demagnetization device is opposite to the magnetization direction of the composite magnetic steel; The performance detection method comprises: After determining the boundary area between the first area and the second area, the method further includes: Obtaining the initial magnetic moment of the composite magnetic steel; Placing the composite magnetic steel in the demagnetization device, controlling the magnetic field strength of the demagnetization magnetic field in the demagnetization device to increase sequentially with a second preset value as an increment, and obtaining a plurality of first magnetic moments of the composite magnetic steel in the process of the magnetic field strength of the demagnetization magnetic field increasing sequentially with the second preset value; When the ratio of the change of the first magnetic moment to the initial magnetic moment to the initial magnetic moment is initially greater than a third preset value, it is determined that the knee coercive force of the composite magnetic steel is within a first range.

7. The performance detection method according to claim 6, characterized in that: After determining that the knee coercivity of the composite magnetic steel is within the first range, the method further includes: Controlling the magnetic field strength of the demagnetization magnetic field in the demagnetization device to be based on the initial endpoint of the first range and to be increased in sequence with a fourth preset value as an increment, and obtaining a plurality of second magnetic moments of the composite magnetic steel during the process in which the magnetic field strength of the demagnetization magnetic field is increased with the fourth preset value, wherein the fourth preset value is less than the second preset value; When the ratio of the change in the second magnetic moment to the initial magnetic moment to the initial magnetic moment is greater than a third preset value for the first time, the knee coercive force of the composite magnetic steel is determined.

8. The performance detection method according to claim 7, characterized in that: After determining the knee coercivity of the composite magnetic steel, the method further includes: Controlling the magnetic field strength of the demagnetization magnetic field in the demagnetization device to increase sequentially with the value of the knee point coercive force as the basic value and with the fifth preset value as the increment, and obtaining a plurality of third magnetic moments of the composite magnetic steel in the process of the magnetic field strength of the demagnetization magnetic field increasing sequentially with the fifth preset value; When the ratio of the change of the third magnetic moment to the initial magnetic moment to the initial magnetic moment is first greater than a sixth preset value, it is determined that the intrinsic coercive force of the composite magnetic steel is in the second range, and the sixth preset value is less than the third preset value.

9. The performance detection method according to claim 8, characterized in that: After determining that the intrinsic coercivity of the composite magnetic steel is within the second range, the method further includes: Controlling the magnetic field strength of the demagnetization magnetic field in the demagnetization device to be based on the initial endpoint of the second range and to be increased in sequence with a seventh preset value as an increment, and obtaining a plurality of fourth magnetic moments of the composite magnetic steel during the process in which the magnetic field strength of the demagnetization magnetic field is increased with the seventh preset value, wherein the seventh preset value is less than the fifth preset value; When the ratio of the change in the fourth magnetic moment to the initial magnetic moment to the initial magnetic moment is greater than a sixth preset value for the first time, the intrinsic coercive force of the composite magnetic steel is determined.

10. The performance detection method according to claim 9, characterized in that: After determining the intrinsic coercivity of the composite magnetic steel, the method further includes: Determine the remanence of the composite magnetic steel according to the first formula and the second formula; and fitting an intrinsic demagnetization curve of the composite magnetic steel according to the knee coercivity of the composite magnetic steel, the intrinsic coercivity of the composite magnetic steel, and the remanence of the composite magnetic steel; The first formula includes: The second formula includes: Wherein, μrec is the recoil permeability, Bdi is the intrinsic magnetic flux density, Pc is the magnetic permeability, L is the thickness of the composite magnetic steel, a is the length of the composite magnetic steel, and b is the width of the composite magnetic steel.

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