Method and device for testing hysteresis of amorphous magnetic core in magnetic sensor

Abstract

The invention discloses a method and device for testing magnetic hysteresis of an amorphous magnetic core in a magnetic sensor, and belongs to the technical field of amorphous magnetic core magnetic hysteresis testing. The device comprises an upper computer, an acquisition system, a power supply, a current source, a relay, a current line copper rod and a test circuit board; the test circuit board is provided with a clamp and a corresponding magnetic flux gate circuit, an amorphous magnetic core to be tested is connected to the magnetic flux gate circuit through the clamp, and a current line copper rod with the two ends connected with the two ends of a current source penetrates through the amorphous magnetic core. The power supply supplies power to the test circuit board, the acquisition system is used for acquiring an initial offset value output by a zero point of each magnetic flux gate circuit on the test circuit board, and the relay is used for controlling the change direction of the current source. And the acquisition system acquires the offset value of each magnetic flux gate circuit on the test circuit board after the positive change and the negative change of the current source, and hysteresis judgment is carried out through the upper computer according to the change of the offset value. According to the method, the amorphous magnetic core with large zero hysteresis of the sensor can be quickly screened from a production source, and the quality of raw materials is further improved.

Description

Technical Field

[0001] The invention belongs to the technical field of amorphous magnetic core hysteresis testing, and in particular relates to a method and a device for testing the hysteresis of an amorphous magnetic core in a magnetic sensor. Background Art

[0002] Amorphous alloy cores have been widely used in power electronics, magnetic sensors and other fields due to their high saturation magnetic induction intensity, low loss and excellent soft magnetic properties. The quality of their performance depends largely on the heat treatment annealing process during the production process, which directly determines the microstructure and magnetic properties of the amorphous alloy core. The heat treatment annealing process involves many process elements, including the precise setting of the annealing temperature point, the reasonable control of the heating rate, the smooth adjustment of the cooling rate, the sufficient guarantee of the insulation time, the effectiveness of the atmosphere protection, the precise application of the DC magnetic field, and the strict requirements of the annealing furnace conditions. Each element has an impact on the performance of the final product and needs to be finely regulated to ensure the stability and consistency of product quality.

[0003] However, in the current mass production process, the heat treatment annealing process still faces many challenges. Due to the complexity of process parameters and the limitations of equipment conditions, the annealing process is often difficult to achieve ideal uniformity and sufficiency. This leads to a series of problems when the amorphous alloy core (a kind of amorphous magnetic core) flows to the downstream sensor production link. Among them, the large zero-point hysteresis of the product is one of the most prominent problems.

[0004] Magnetic hysteresis refers to the phenomenon that the magnetization intensity of ferromagnetic materials depends not only on the strength of the external magnetic field, but also on the magnetization history during the magnetization and demagnetization process of ferromagnetic materials. In sensors with soft magnetic materials as cores, this is manifested as an offset in the zero-point output. It also increases the sensitivity of the core to geomagnetic interference, making the sensor susceptible to interference from the external magnetic field in practical applications, thereby affecting the accuracy and stability of the sensor.

[0005] The Chinese invention patent application with publication number CN113687281A provides a test and measurement instrument for determining the core loss, which receives a primary current signal from the primary winding of the device under test and a primary voltage signal measured across the core of the device under test, and determines the magnetic loss of the device under test based on the primary current signal and the primary voltage signal. The Chinese utility model patent application with publication number CN203133262U provides a system for detecting the properties of a magnetic sensor, which can test the magnetic field-voltage relationship, sensitivity, linearity, hysteresis and other characteristics of the magnetic sensor, and then determine whether the magnetic sensor is qualified and classify the property level of the magnetic sensor. However, these methods are mainly for testing assembled inductors or sensor devices, and cannot directly trace back to the individual performance of the core component, the magnetic core, and control product quality from the source.

[0006] In order to solve these problems, it is necessary to accurately measure the hysteresis characteristics of the incoming amorphous cores through professional testing equipment before the amorphous cores enter the magnetic sensor production process, so as to screen out amorphous cores with unqualified hysteresis performance at the source of magnetic sensor production and identify amorphous cores that are sensitive to geomagnetic interference. Summary of the invention

[0007] In view of the above, the purpose of the present invention is to provide a method and device for testing the hysteresis of an amorphous magnetic core in a magnetic sensor. By making a set of magnetic core detection devices, adapting the applied fluxgate circuit, and cooperating with the host computer to write the test logic, the AC and DC test methods are applied to test the zero-point output offset of the sensor, and the amorphous magnetic core with large zero-point hysteresis of the sensor is screened out, the quality of the raw materials is further purified, the anti-interference ability and stability of the final product are improved as a whole, and the overall performance and reliability of the product are guaranteed.

[0008] In order to achieve the above-mentioned invention object, the technical solution provided by the present invention is as follows: An embodiment of the present invention provides a device for testing hysteresis of an amorphous magnetic core in a magnetic sensor, comprising: Host computer, acquisition system, power supply, current source, relay, current wire copper rod and test circuit board; The test circuit board is provided with a fixture and a corresponding fluxgate circuit, and the amorphous magnetic core to be tested is connected to the fluxgate circuit through the fixture, and at the same time, a current wire copper rod passes through the amorphous magnetic core, and two ends of the current wire copper rod are respectively connected to two ends of the current source; The power supply is used to supply power to the test circuit board, the acquisition system is used to acquire the initial offset value of the zero-point output of each fluxgate circuit on the test circuit board after the power supply is powered on, the relay is used to control the change direction of the current source, and the acquisition system acquires the first offset value of the zero-point output of each fluxgate circuit on the test circuit board after the current source changes in the positive direction, and the second offset value of the zero-point output after the current source changes in the negative direction, and the host computer performs hysteresis judgment based on the difference between the first offset value and the initial offset value, and the difference between the second offset value and the initial offset value.

[0009] Preferably, a plurality of fixtures and their corresponding fluxgate circuits are arranged in a row on the test circuit board, and each amorphous magnetic core to be tested is connected to each fluxgate circuit through each fixture, and at the same time, the current line copper rod passes through all the amorphous magnetic cores to be tested, thereby realizing multi-station magnetic core detection.

[0010] Preferably, the power supply, current source and relay are uniformly controlled by the host computer through the acquisition system.

[0011] Preferably, collecting the first offset value of the zero-point output of each fluxgate circuit on the test circuit board after the current source changes in the positive direction includes: controlling the positive adjustment of the DC output of the current source to reach a current N times the rated value and return to the zero point again, and collecting the first offset value of the zero-point output at this time.

[0012] Preferably, collecting the second offset value of the zero-point output of each fluxgate circuit on the test circuit board after the current source changes negatively includes: controlling the negative adjustment of the DC output of the current source to reach a current N times the rated value and return to zero again, and collecting the second offset value of the zero-point output at this time.

[0013] Preferably, the host computer performs hysteresis judgment according to the difference between the first offset value and the initial offset value, and the difference between the second offset value and the initial offset value, including: The host computer comprehensively determines whether the difference between the first offset value and the initial offset value, and the difference between the second offset value and the initial offset value are within the offset value accuracy variation range designed for the magnetic sensor. If both differences are within the design range, it means that the hysteresis of the amorphous magnetic core is within an acceptable range and the geomagnetic interference is small. If any difference is outside the design range, it means that the hysteresis of the amorphous magnetic core is not within the acceptable range and the geomagnetic interference is large.

[0014] To achieve the above-mentioned purpose of the invention, an embodiment of the present invention further provides a method for testing the hysteresis of an amorphous magnetic core in a magnetic sensor, which is implemented by using the above-mentioned device for testing the hysteresis of an amorphous magnetic core in a magnetic sensor, and includes the following steps: The amorphous magnetic core to be tested is connected to the fluxgate circuit through the fixture on the test circuit board, and a current wire copper rod with two ends connected to the two ends of the current source is passed through the amorphous magnetic core to be tested; The acquisition system acquires the initial offset value of the zero-point output of each fluxgate circuit on the test circuit board after the power supply is powered on, the relay controls the change direction of the current source, and the acquisition system acquires the first offset value of the zero-point output of each fluxgate circuit on the test circuit board after the current source changes in a positive direction, and the second offset value of the zero-point output after the current source changes in a negative direction; The host computer performs hysteresis judgment according to the difference between the first offset value and the initial offset value, and the difference between the second offset value and the initial offset value.

[0015] Preferably, several amorphous magnetic cores to be tested are connected to several fixtures arranged in a row and their corresponding fluxgate circuits at the same time, and the current line copper rod is passed through all the amorphous magnetic cores to be tested, so as to perform multi-station magnetic core testing.

[0016] Preferably, the positive adjustment of the DC output of the current source is controlled to reach a current N times the rated value and return to zero again, and the first offset value of the zero point output at this time is collected; the negative adjustment of the DC output of the current source is controlled to reach a current N times the rated value and return to zero again, and the second offset value of the zero point output at this time is collected.

[0017] Preferably, the host computer makes a comprehensive judgment through a detection program. If the difference between the two offset values ​​is within the design range, it means that the hysteresis of the amorphous magnetic core is within an acceptable range and the geomagnetic interference is small. If the difference between any offset value is outside the design range, it means that the hysteresis of the amorphous magnetic core is not within the acceptable range and the geomagnetic interference is large.

[0018] Compared with the prior art, the present invention has the following beneficial effects: The present invention can screen out the problem of large hysteresis of amorphous cores caused by insufficient annealing before the finished magnetic sensor test stage, and can also screen out the problem caused by large geomagnetic interference. The present invention can prevent unqualified amorphous cores from entering the subsequent sensor test stage and flowing to the downstream application end, and prevent the detection accuracy of the application end from being reduced due to large hysteresis of the core. In addition, by eliminating amorphous cores with poor hysteresis performance, the present invention plays a key role in improving the consistency and stability of the overall performance of the sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0020] Figure 1 It is a structural schematic diagram of a device for testing hysteresis of an amorphous magnetic core in a magnetic sensor provided by an embodiment of the present invention.

[0021] Figure 2 It is a schematic flow chart of a method for testing hysteresis of an amorphous magnetic core in a magnetic sensor provided by an embodiment of the present invention.

[0022] The specific symbols in the accompanying drawings are: 1. Host computer; 2. Acquisition system; 3. Power supply; 4. Current source; 5. Relay; 6. Current line copper rod; 7. Test circuit board; 8. Amorphous magnetic core. DETAILED DESCRIPTION

[0023] To make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific implementation methods described herein are only used to explain the present invention and do not limit the scope of protection of the present invention.

[0024] The inventive concept of the present invention is: in view of the problem that the prior art lacks the ability to control the performance of the magnetic core and the product quality in the magnetic sensor from the source, the embodiments of the present invention provide a method and device for testing the hysteresis of the amorphous magnetic core in the magnetic sensor. By measuring the change in the zero-point output offset value of the amorphous magnetic core under the positive and negative changes of the current source, it is determined whether there is hysteresis and geomagnetic interference, thereby achieving the pre-screening of hysteresis problems and geomagnetic problems of the amorphous magnetic core product.

[0025] Figure 1 Schematic diagram of the structure of the test device for the hysteresis of the amorphous magnetic core in the magnetic sensor provided by the embodiment of the present invention. Figure 1 As shown, the embodiment provides a test device for the hysteresis of an amorphous magnetic core in a magnetic sensor, including: a host computer 1, an acquisition system 2, a power supply 3, a current source 4, a relay 5, a current wire copper rod 6 and a test circuit board 7.

[0026] In the embodiment, the acquisition system 2 is used to acquire the initial offset value offset of the zero-point output of each fluxgate circuit on the test circuit board 7 after the power supply 3 is powered on, and is used to acquire the first offset value offset1 of the zero-point output of each fluxgate circuit on the test circuit board 7 after the current source 4 changes positively, and the second offset value offset2 of the zero-point output after the current source 4 changes negatively, and sends offset, offset1, and offset2 to the host computer 1.

[0027] When the control changes in the positive direction, the relay 5 controls the positive adjustment of the DC output of the current source 4 to reach a current N times the rated value and return to the zero point again, and the first offset value offset1 of the zero point output at this time is collected.

[0028] When the control changes in the negative direction, the negative adjustment of the DC output of the current source 4 is controlled by the relay 5 to reach a current N times the rated value and return to the zero point again, and the second offset value offset2 of the zero point output at this time is collected.

[0029] In the embodiment, the power supply 3 is used to supply power to the test circuit board 7 .

[0030] In the embodiment, the positive and negative electrodes at both ends of the current source 4 are used to connect the two ends of the current wire copper rod 6, and the change of the current direction is controlled by the relay 5.

[0031] In the embodiment, the relay 5 is used to control the current change direction of the current source 4 .

[0032] In the embodiment, the current wire copper rod 6 is used to directly pass through the center holes of all the annular amorphous magnetic cores 8 to be tested.

[0033] In the embodiment, the test circuit board 7 has a plurality of fixtures arranged in a row and a plurality of corresponding fluxgate circuits. Each amorphous magnetic core 8 to be tested is connected to each fluxgate circuit through each fixture. A current wire copper rod 6 passes through all the amorphous magnetic cores 8 to be tested at the same time. Both ends of the current wire copper rod 6 are respectively connected to both ends of the current source 4, thereby supporting multi-station rapid magnetic core detection.

[0034] In the embodiment, the host computer 1 is used to uniformly control the power supply 3, the current source 4 and the relay 5 through the acquisition system 2. The host computer 1 is also used to calculate Δoff1= offset1-offset and Δoff2= offset2-offset according to the acquired initial offset value offset, the first offset value offset1, and the second offset value offset2, and comprehensively judge whether Δoff1 and Δoff2 are within the offset value accuracy variation range designed for the magnetic sensor through the built-in system software. If both Δoff1 and Δoff2 are within the design range, it means that the magnetic core has no hysteresis and the geomagnetic interference is small. If either Δoff1 or Δoff2 is outside the design range, it means that the magnetic core has hysteresis and the geomagnetic interference is large.

[0035] In summary, the hysteresis testing device of amorphous magnetic core in magnetic sensor provided by the present invention can efficiently and accurately detect the hysteresis of amorphous magnetic core used in magnetic sensors, especially microcurrent sensors, so as to improve the overall performance and reliability of the sensor product production chain.

[0036] Based on the same inventive concept, Figure 2 As shown, an embodiment of the present invention further provides a method for testing the hysteresis of an amorphous magnetic core in a magnetic sensor, comprising the following steps: S1, connect the amorphous magnetic core to the fluxgate circuit through the fixture on the test circuit board, and pass the current wire copper rod with both ends connected to the two ends of the current source through the amorphous magnetic core to be tested.

[0037] S2, the acquisition system acquires the initial offset value of the zero-point output of each fluxgate circuit on the test circuit board after the power is turned on, the relay controls the change direction of the current source, and the acquisition system acquires the first offset value of the zero-point output of each fluxgate circuit on the test circuit board after the current source changes in the positive direction, and the second offset value of the zero-point output after the current source changes in the negative direction.

[0038] S3, the host computer performs hysteresis judgment according to the difference between the first offset value and the initial offset value, and the difference between the second offset value and the initial offset value.

[0039] It should be noted that the method for testing the hysteresis of an amorphous magnetic core in a magnetic sensor provided in the above embodiment and the device for testing the hysteresis of an amorphous magnetic core in a magnetic sensor belong to the same inventive concept. The specific implementation process is detailed in the embodiment of the device for testing the hysteresis of an amorphous magnetic core in a magnetic sensor, which will not be repeated here.

[0040] The specific implementation methods described above provide a detailed description of the technical solutions and beneficial effects of the present invention. It should be understood that the above is only the most preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, supplements and equivalent substitutions made within the scope of the principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A device for testing the hysteresis of an amorphous magnetic core in a magnetic sensor, characterized in that: include: Host computer, acquisition system, power supply, current source, relay, current wire copper rod and test circuit board; The test circuit board is provided with a fixture and a corresponding fluxgate circuit, and the amorphous magnetic core to be tested is connected to the fluxgate circuit through the fixture, and at the same time, a current wire copper rod passes through the amorphous magnetic core, and two ends of the current wire copper rod are respectively connected to two ends of the current source; The power supply is used to supply power to the test circuit board, the acquisition system is used to acquire the initial offset value of the zero-point output of each fluxgate circuit on the test circuit board after the power supply is powered on, the relay is used to control the change direction of the current source, and the acquisition system acquires the first offset value of the zero-point output of each fluxgate circuit on the test circuit board after the current source changes in the positive direction, and the second offset value of the zero-point output after the current source changes in the negative direction, and the host computer performs hysteresis judgment based on the difference between the first offset value and the initial offset value, and the difference between the second offset value and the initial offset value.

2. The device for testing hysteresis of amorphous core in a magnetic sensor according to claim 1, characterized in that: Several fixtures and their corresponding fluxgate circuits are arranged in a row on the test circuit board. Each amorphous magnetic core to be tested is connected to each fluxgate circuit through each fixture. At the same time, the current line copper rod passes through all the amorphous magnetic cores to be tested, realizing multi-station magnetic core detection.

3. The device for testing the hysteresis of an amorphous magnetic core in a magnetic sensor according to claim 1, characterized in that: The host computer controls the power supply, current source and relay uniformly through the acquisition system.

4. The device for testing hysteresis of amorphous core in a magnetic sensor according to claim 1, characterized in that: The first offset value of the zero-point output of each fluxgate circuit on the test circuit board is collected after the current source changes in the positive direction, including: controlling the positive adjustment of the DC output of the current source to reach a current N times the rated value and return to the zero point again, and collecting the first offset value of the zero-point output at this time.

5. The device for testing the hysteresis of an amorphous magnetic core in a magnetic sensor according to claim 1, characterized in that: The second offset value of the zero-point output of each fluxgate circuit on the test circuit board is collected after the current source changes negatively, including: controlling the negative adjustment of the DC output of the current source to reach a current N times the rated value and return to the zero point again, and collecting the second offset value of the zero-point output at this time.

6. The device for testing the hysteresis of an amorphous magnetic core in a magnetic sensor according to claim 1, characterized in that: The host computer performs hysteresis judgment according to the difference between the first offset value and the initial offset value, and the difference between the second offset value and the initial offset value, including: The host computer comprehensively determines whether the difference between the first offset value and the initial offset value, and the difference between the second offset value and the initial offset value are within the offset value accuracy variation range designed for the magnetic sensor. If both differences are within the design range, it means that the hysteresis of the amorphous magnetic core is within an acceptable range and the geomagnetic interference is small. If any difference is outside the design range, it means that the hysteresis of the amorphous magnetic core is not within the acceptable range and the geomagnetic interference is large.

7. A method for testing the hysteresis of an amorphous magnetic core in a magnetic sensor, implemented by using the device for testing the hysteresis of an amorphous magnetic core in a magnetic sensor according to any one of claims 1 to 6, characterized in that: The following steps are involved: The amorphous magnetic core to be tested is connected to the fluxgate circuit through the fixture on the test circuit board, and a current wire copper rod with two ends connected to the two ends of the current source is passed through the amorphous magnetic core to be tested; The acquisition system acquires the initial offset value of the zero-point output of each fluxgate circuit on the test circuit board after the power supply is powered on, the relay controls the change direction of the current source, and the acquisition system acquires the first offset value of the zero-point output of each fluxgate circuit on the test circuit board after the current source changes in a positive direction, and the second offset value of the zero-point output after the current source changes in a negative direction; The host computer performs hysteresis judgment according to the difference between the first offset value and the initial offset value, and the difference between the second offset value and the initial offset value.

8. The method for testing the hysteresis of an amorphous magnetic core in a magnetic sensor according to claim 7, characterized in that: At the same time, several amorphous magnetic cores to be tested are connected to several fixtures arranged in a row and several corresponding fluxgate circuits, and the current line copper rod passes through all the amorphous magnetic cores to be tested to perform multi-station magnetic core testing.

9. The method for testing the hysteresis of an amorphous magnetic core in a magnetic sensor according to claim 7, characterized in that: The positive adjustment of the DC output of the current source is controlled to reach a current N times the rated value and return to the zero point again, and the first offset value of the zero point output is collected at this time; the negative adjustment of the DC output of the current source is controlled to reach a current N times the rated value and return to the zero point again, and the second offset value of the zero point output is collected at this time.

10. The method for testing the hysteresis of an amorphous magnetic core in a magnetic sensor according to claim 7, characterized in that: The host computer makes a comprehensive judgment through the detection program. If the difference between the two offset values ​​is within the design range, it means that the hysteresis of the amorphous core is within the acceptable range and the geomagnetic interference is small. If the difference of any offset value is outside the design range, it means that the hysteresis of the amorphous core is not within the acceptable range and the geomagnetic interference is large.

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