A method, system and device for calculating vector magnetic field

Abstract

The present invention provides a method for calculating a vector magnetic field. By arranging at least two magnetic sensors in the vector magnetic field, the mapping relationship between the signals of the magnetic sensors and the magnetic field at the position to be measured is obtained, and the magnetic field at the position to be measured is calculated according to the output data of the magnetic sensors, which has the effects of fast calculation speed, high calculation accuracy and small error. A vector magnetic field calculation system and device are also provided.

Description

Technical Field

[0001] The present invention belongs to the technical field of magnetic variable measurement, and particularly relates to a method, system and device for calculating a vector magnetic field. Background Art

[0002] In order to obtain the magnetic field situation at a certain position in space, that is, the magnetic field situation at the position to be measured, methods such as directly measuring the magnetic field at this position and calculating based on the magnetic field situations at other positions are usually adopted. Among them, in some scenarios, the space where the position to be measured is located is occupied by other devices, resulting in the inability to directly measure the magnetic field situation at the position to be measured, and only the magnetic field situation at the position to be measured can be calculated through the magnetic field situations at other positions. For example, when using a magnetic characterization device to detect the magnetic properties of a device to be measured, it is often necessary to detect the magnetic field situation at the position of the device to be measured in real time, that is, the magnetic field situation at the aforementioned position to be measured. However, the magnetic field measurement device usually has a certain size and can only get as close as possible to the device to obtain the magnetic field situation near the position to be measured, and cannot be directly placed at the position to be measured to obtain the magnetic field situation here, and can only calculate the magnetic field situation at the position to be measured through the magnetic field situations at other positions. More specifically, during the test of a magnetic semiconductor device, such as in common semiconductor magnetic characterization devices such as a magnetic probe station, a Kerr microscope, and a magneto-optical Kerr test system, the sample is placed at the center of the magnetic field, and it is necessary to monitor the magnetic field situation at the position of the sample in real time, while the magnetic field measurement device cannot directly measure this data. Therefore, how to obtain the magnetic field situation at the position to be measured through the magnetic field situations at other positions is an important problem that needs to be solved urgently. Summary of the Invention

[0003] In view of the problem of how to calculate the magnetic field situation at the position to be measured through the magnetic field situations at other positions, the present invention proposes a method, system and device for calculating a vector magnetic field.

[0004] Specifically, it includes the following contents:

[0005] A method for calculating a vector magnetic field, including: setting at least two magnetic sensors in the vector magnetic field, the magnetic sensors being sensitive to the vector magnetic field and the magnetic field sensitive directions forming an angle; calculating the magnetic field at the position to be measured according to the mapping relationship between the magnetic sensors and the magnetic field at the position to be measured in the vector magnetic field and the output data of the magnetic sensors.

[0006] Preferably, the vector magnetic field is provided by an electromagnet. Further, the electromagnet is powered by a current source.

[0007] The obtaining method of the mapping relationship includes:

[0008] S11: Place the measurement part of the magnetic field measurement device at the position to be measured in the vector magnetic field to make the measurement part sensitive to the vector magnetic field;

[0009] S12: Adjust the vector magnetic field to make the magnetic field strength measured by the magnetic field measuring device be 0, and record the output signal of the magnetic sensor;

[0010] S13: Change the vector magnetic field, and record the data measured by the magnetic field measuring device and the corresponding output signals of the magnetic sensor during the changing process;

[0011] S14: According to the output signal of the magnetic sensor when the magnetic field strength at the position to be measured is 0, perform intercept processing on the obtained output signal of the magnetic sensor to obtain the output signal of the magnetic sensor after intercept processing;

[0012] S15: Based on the output signal of the magnetic sensor after intercept processing and the data measured by the magnetic field measuring device, obtain the mapping relationship between the magnetic sensor and the magnetic field at the position to be measured in the vector magnetic field.

[0013] Preferably, in S11, the measuring part is sensitive to one component of the vector magnetic field; the method for obtaining the mapping relationship further includes: S16: Make the measuring part sensitive to other components of the vector magnetic field, and respectively perform S12 - S15 again.

[0014] Further, the output signal of the magnetic sensor is in the linear segment. Preferably, the magnetic sensor is a Hall sensor.

[0015] Preferably, the vector magnetic field is provided by an electromagnet; in S12, the magnetic field strength measured by the magnetic field measuring device is made 0 through oscillating demagnetization.

[0016] Optionally, the current waveform of the oscillating demagnetization is at least one of a square wave, a triangular wave, and a sine wave.

[0017] Preferably, the vector magnetic field is provided by an electromagnet; in S13, the vector magnetic field is changed by traversing the excitation current of the electromagnet.

[0018] Optionally, the excitation current is traversed with a preset step size.

[0019] Optionally, the sensitive directions of at least two magnetic sensors are perpendicular to each other.

[0020] Optionally, the sensitive direction of the measuring part of the magnetic field measuring device is the same as the sensitive direction of the magnetic sensor.

[0021] Optionally, the magnetic sensor is calibrated before calculating the magnetic field at the position to be measured.

[0022] Preferably, the calibration method includes:

[0023] S21: Adjust the vector magnetic field so that the magnetic field strength measured by the magnetic field measurement device is 0, and record the output signal of the magnetic sensor.

[0024] S22: According to the output signal of the magnetic sensor when the magnetic field strength at the position to be measured is 0, perform intercept processing on the obtained output signal of the magnetic sensor to obtain the output signal of the magnetic sensor after intercept processing, which is used as the input of the mapping relationship.

[0025] Optionally, the way to obtain the mapping relationship can also be: including:

[0026] T11: Place the measurement part of the magnetic field measurement device at at least two intermediate positions of the vector magnetic field, so that the measurement part is sensitive to the vector magnetic field, and the position to be measured is located between the two intermediate positions.

[0027] T12: Change the vector magnetic field and record the data measured by the magnetic field measurement device and the corresponding output signals of the magnetic sensor during the change process.

[0028] Furthermore, when calculating the magnetic field at the position to be measured, the positional relationship between the position to be measured and the intermediate positions is also used.

[0029] A vector magnetic field calculation system includes: a vector magnetic field module, a magnetic sensor module, and an analysis module. The vector magnetic field module is configured to provide a vector magnetic field. Data exchange occurs between the magnetic sensor module and the analysis module. The magnetic sensor module includes at least two magnetic sensors. The magnetic sensors are sensitive to the vector magnetic field and the magnetic sensitive directions form an angle. The analysis module is configured to be able to output the magnetic field information of the position to be measured according to the data provided by the magnetic sensors.

[0030] Optionally, the analysis module can also perform correction processing on the output signals of the magnetic sensors.

[0031] A vector magnetic field calculation device includes: an exciting device, magnetic sensors, an exciting power supply, a sensor power supply, and a data collector. The exciting device includes at least two electromagnets. The exciting power supply supplies power to the exciting device. The magnetic circuits of the electromagnets are arranged at an angle. The magnetic sensors are at least two. The sensitive directions of the magnetic sensors are arranged at an angle and are sensitive to the magnetic field generated by the exciting device. The sensor power supply supplies power to the magnetic sensors. The magnetic sensors are communicatively connected to the data collector.

[0032] Optionally, the magnetic sensors are arranged on the magnetic circuits of the electromagnets, and the magnetic sensors are sensitive to the magnetic field of their respective magnetic circuits.

[0033] Optionally, the number of the electromagnets is three. Among them, two of the electromagnets are arranged opposite to each other, and the axis of the other electromagnet is vertically intersecting with the connection line of the electromagnets arranged opposite to each other.

[0034] Optionally, the number of the electromagnets is three, and the magnetic circuits of the three electromagnets vertically intersect at one point.

[0035] Optionally, the electromagnets include a first group, a second group, and a third group. Both the first group and the second group include electromagnets arranged opposite to each other. The third group includes at least one electromagnet. The first group, the second group, and the third group are perpendicular to each other and intersect at one point.

[0036] The present application has at least the following beneficial effects: fast calculation speed, reducing the complexity of magnetic field calculation, improving the calculation efficiency, thus reducing the time required for magnetic field measurement. In the scenario of rapid magnetic field change, it can greatly reduce the delay and the corresponding compensation value, and further greatly improve the calculation accuracy.

[0037] In addition, the present application also has the following additional beneficial effects:

[0038] Improving the accuracy of vector magnetic field calculation, completely eliminating the error in the intercept term in the signal of the magnetic sensor, eliminating the influence of zero drift, that is, greatly improving the calculation accuracy in weak magnetic fields; simplifying the fitting process of the mapping relationship, reducing the calculation complexity and calculation time, and being able to quickly complete the fitting of the mapping relationship; further reducing the complexity of magnetic field calculation and the fitting difficulty, improving the calculation efficiency, thus reducing the time required for equipment calibration and signal processing during use;

[0039] It can save the time required for function fitting, and can flexibly adjust the balance between the acquisition time and accuracy of the mapping relationship to meet various detection requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a schematic structural diagram of a vector magnetic field.

[0041] Figure 2 It is another schematic structural diagram of a vector magnetic field.

[0042] Figure 3 It is still another schematic structural diagram of a vector magnetic field. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0043] To make the objectives and features of the present invention more obvious and understandable, the following further describes the specific embodiments of the present invention with reference to the drawings. It should be noted that the drawings are all in a very simplified form and use non-precise ratios, and are only used to conveniently and clearly assist in explaining the objectives of the embodiments of the present invention.

[0044] For clarity, in the following description, well-known functions and structures are not described in detail, because they would obscure the present invention with unnecessary details. It should be recognized that in the development of any actual embodiment, numerous implementation details must be made to achieve the specific goals of the developer.

[0045] The vector magnetic field can be achieved by making the magnetic circuits of the electromagnets form a certain angle. For example, Figure 1 A form of generating a vector magnetic field is shown, in which the electromagnets 110 and 120 are arranged opposite to each other along the first axis 6, and the magnetic circuits formed by the electromagnets 110 and 120 are located on the first axis 6; the electromagnet 120 is arranged along the second axis 7, and the magnetic circuit of the electromagnet 120 is located on the second axis 7; the first axis 6 and the second axis 7 are perpendicular to each other and intersect. By controlling the magnetic field intensities generated by the electromagnets 110, 120, and 130, a variable vector magnetic field environment is formed. Figure 2 A form of generating a vector magnetic field is shown, in which the electromagnets 110 and 120 are arranged at an angle, the magnetic circuit of the electromagnet 110 is located on the first axis 6, the magnetic circuit of the electromagnet 120 is located on the second axis 7, and the first axis 6 and the second axis 7 form an angle and the angle is not a right angle. Figure 3 Another form of generating a vector magnetic field is shown, in which the electromagnets 140 and 150 are arranged opposite to each other as the first group, and the formed magnetic circuit is located on the first axis 6; the electromagnets 160 and 170 are arranged opposite to each other as the second group, and the formed magnetic circuit is located on the second axis 7; the electromagnet 180 is arranged alone as the third group, and the formed magnetic circuit is located on the third axis 8; the first axis 6, the second axis 7, and the third axis 8 are perpendicular to each other and intersect at a point. It can be foreseen that the first axis 6, the second axis 7, and / or the third axis 8 are not limited to the form of perpendicular intersection, and can also form a preset angle, for example, an acute angle or an obtuse angle; the number of electromagnets is not limited to two, three, or five, and can also be other numbers for generating a vector magnetic field, and those skilled in the art can select the corresponding number of electromagnets according to requirements. In addition, it can be foreseen that in addition to using electromagnets, some electromagnets can be replaced by permanent magnets, and by changing the position, direction, attitude, shape, volume, magnetic field intensity, etc. of the permanent magnets, the required vector magnetic field can be formed.

[0046] Figure 1 、 Figure 2 In, the magnetic sensor 200 is powered by the sensor power supply 400; the magnetic sensor 200 is communicatively connected to the signal collector 500. The signal collector 500 can be an oscilloscope, or a data acquisition circuit, a memory, or after being processed by a signal processing device, stored in the memory.

[0047] Next, the method for calculating the vector magnetic field will be described.

[0048] A method for calculating a vector magnetic field includes: setting at least two magnetic sensors 200 in the vector magnetic field, where the magnetic sensors 200 are sensitive to the vector magnetic field and the magnetic sensitive directions form an angle; calculating the magnetic field at a position to be measured according to the mapping relationship between the magnetic sensors 200 and the magnetic field at the position to be measured in the vector magnetic field and the output data of the magnetic sensors, as Figure 1 shown, collecting the output signals of the magnetic sensors 200, here collecting the Hall voltage of the Hall sensor, and calculating the magnetic field at the position to be measured according to the mapping relationship.

[0049] In the form as Figure 1 shown, the vector magnetic field is generated by electromagnets 110, 120, 130. Magnetic sensors 200 are respectively arranged at the magnetic core pole heads 103 of the electromagnets 110, 130. The magnetic sensors 200 adopt Hall sensors. The two magnetic sensors 200 are sensitive to the magnetic fields generated by the electromagnets 110, 120, 130, especially sensitive to the magnetic fields generated by the electromagnets 110, 130 respectively. In Figure 3 the form shown, the vector magnetic field is generated by electromagnets 140, 150, 160, 170, 180. Magnetic sensors 200 are respectively arranged at the pole heads 103 of the electromagnets 140, 160, 180. The magnetic sensors 200 adopt Hall sensors. The three magnetic sensors 200 are respectively sensitive to the magnetic fields generated by the electromagnets 140, 150, 160, 170, 180, especially sensitive to the magnetic fields generated by the electromagnets 140, 160, 180. In Figure 2 the form shown, the vector magnetic field is generated by electromagnets 110, 130. Magnetic sensors 200 are respectively arranged at the magnetic core pole heads 103 of the electromagnets 110, 130. The magnetic sensors 200 adopt Hall sensors. The two magnetic sensors 200 are sensitive to the magnetic fields generated by the electromagnets 110, 130.

[0050] This method for calculating the vector magnetic field directly uses the signals measured by multiple magnetic sensors and calculates the magnetic field at the position to be measured according to the corresponding mapping relationship. The calculation speed is fast, skipping the calculation process between the magnetic field measured by the magnetic sensor and the magnetic field at the position to be measured, reducing the complexity of the magnetic field calculation, improving the calculation efficiency, thus reducing the time required for magnetic field measurement. In the scenario of rapid magnetic field change, it can greatly reduce the delay and the corresponding compensation value, and further greatly improve the calculation accuracy.

[0051] Next, the method for obtaining the mapping relationship will be described.

[0052] During the processing of magnetic sensors such as Hall sensors, factors such as asymmetric electrode geometric positions, poor electrode ohmic contact, non-uniform resistivity, and non-uniform temperature will cause the magnetic sensors to produce zero drift. Therefore, it is necessary to consider the influence of the zero drift of the magnetic sensors on the calculation accuracy.

[0053] In Figure 1 、 Figure 2 any form of magnetic field, the magnetic sensor 200 uses a Hall sensor, and the magnetic field measuring device uses a gaussmeter 300; the vector magnetic field can be decomposed into a magnetic field component H x along the x-axis and a magnetic field component H y along the y-axis. The acquisition method of the mapping relationship is as follows:

[0054] S11: Place the measuring part 301 of the gaussmeter 300 at the position to be measured in the vector magnetic field, and make the placement direction of the measuring part 301 sensitive to the magnetic field component along the x-axis.

[0055] S12: Demagnetize the electromagnet so that the magnetic field intensity measured by the magnetic field measuring device, i.e., the gaussmeter 300, is 0, and record the voltages b 1i 、b 2i of the two Hall sensors after demagnetization is completed;

[0056] S13: Traverse the excitation current of the electromagnet at a preset step size, and record H x at the measuring part 301 and the corresponding Hall voltages (V1, V2) of the two Hall sensors during the current change process;

[0057] S14: Perform an intercept processing on the recorded Hall voltages (V1, V2) (V1 - b 1i , V2 - b 2i ), that is, make V1 ＇ = V1 - b 1i , V2 ＇ = V2 - b 2i , and obtain the Hall voltages (V1 ＇ , V2 ＇ ) after the intercept processing;

[0058] S15: Based on the Hall voltages (V1 ＇ , V2 ＇ ) after the intercept processing and H x measured by the gaussmeter 300, fit to obtain H x = f(V1 ＇ , V2 ＇ );

[0059] S16: Make the placement direction of the measuring part 301 sensitive to the magnetic field component along the y-axis, and perform S12 - S15 again. Based on the Hall voltages (V1 ＇ , V2 ＇ ) after the intercept processing and H y measured by the gaussmeter 300, fit to obtain H y = f(V1 ＇ , V2 ＇ ).

[0060] In S11, if the gaussmeter 300 can simultaneously measure the x-axis magnetic field component H at the measurement unit 301 x , y-axis magnetic field component H y , then there is no need to repeat the process of S16. In S15, H x = f(V1 ＇ , V2 ＇ ) and H y = f(V1 ＇ , V2 ＇ ) can be fitted simultaneously.

[0061] Among them, the preset step lengths for increasing the current of the electromagnets in S13 and S14 can be the same or different.

[0062] According to Figure 1 the shown setting form, make the excitation currents of the electromagnets 110 and 120 the same and their magnetic poles in the same direction. Accordingly, in S13, the excitation currents of the electromagnets 110, 120, and 130 can be traversed in the following manner:

[0063] S131: Fix the excitation currents of the electromagnets 110 and 120, and increase the current of the electromagnet 130 from I3min to I3max at a preset step length;

[0064] S132: Increase the excitation currents of the electromagnets 110 and 120 by a preset step length, and perform S131 - S132 again to make the excitation current of the electromagnet 110 range from I1min to I1max.

[0065] According to Figure 2 the shown setting form, in S13, the excitation currents of the electromagnets 110 and 130 can be traversed in the following manner:

[0066] S131: Fix the excitation current of the electromagnet 110, and increase the current of the electromagnet 130 from I3min to I3max at a preset step length;

[0067] S132: Increase the excitation current of the electromagnet 110 by a preset step length, and perform S131 - S132 again to make the excitation current of the electromagnet 110 range from I1min to I1max.

[0068] Figure 2 And the corresponding calculation content shows the process of fitting the mapping relationship between the magnetic sensor voltage of the non-vertically set electromagnet and the magnetic field at the position to be measured. According to Figure 2 the shown content, it can be clearly known that the vector magnetic field calculation method proposed by the present invention can be further extended to the calculation of vector magnetic fields composed of other angles and other numbers of electromagnets.

[0069] Figure 3 shows a form of three-dimensional vector magnetic field, in which magnetic sensors, such as Hall sensors, are attached to the pole heads of electromagnets 140, 160, and 180; the magnetic field measuring device uses a gaussmeter 300. According to Figure 3 the shown electromagnets, the fitting method of the mapping relationship in the three-dimensional vector magnetic field is described as follows:

[0070] S11: Place the measuring part 301 of the gaussmeter 300 in the vector magnetic field so that the placement direction of the measuring part 301 is sensitive to the magnetic field component along the x-axis.

[0071] S12: Demagnetize the electromagnet so that the magnetic field intensity measured by the magnetic field measuring device, i.e., the gaussmeter 300, is 0, and record the voltages b 1i 、b 2i 、b 3i of the three Hall sensors after demagnetization is completed;

[0072] S13: Traverse the excitation current of the electromagnet at a preset step size, and record the magnetic field value H x at the measuring part 301 and the corresponding Hall voltages (V1, V2, V3) of the three Hall sensors during the current change process;

[0073] S14: Perform intercept processing on the recorded Hall voltages (V1, V2, V3) (V1 - b 1i , V2 - b 2i , V3 - b 3i ), that is, make V1 ＇ = V1 - b 1i , V2 ＇ = V2 - b 2i , V3 ＇ = V3 - b 3i , and obtain the Hall voltages (V1 ＇ , V2 ＇ , V3 ＇ ) after intercept processing;

[0074] S15: Based on the Hall voltages (V1 ＇ , V2 ＇ , V3 ＇ ) after intercept processing and the magnetic field intensity H x measured by the gaussmeter 300, fit to obtain H x = f(V1 ＇ , V2 ＇ , V3 ＇ );

[0075] S16: Make the placement direction of the measuring part 301 sensitive to the magnetic field component along the y-axis, and perform S12 - S15 again. Based on the Hall voltages (V1 ＇ , V2＇ , V3 ＇ ), the magnetic field strength H measured by the gaussmeter 300 y , and H is obtained by fitting y = f(V1 ＇ , V2 ＇ , V3 ＇ ); Make the placement direction of the measurement unit 301 sensitive to the magnetic field component along the z-axis, and perform S12 - S15 again. Based on the Hall voltage (V1 ＇ , V2 ＇ , V3 ＇ ) after intercept processing and the magnetic field strength H measured by the gaussmeter 300 z , and H is obtained by fitting z = f(V1 ＇ , V2 ＇ , V3 ＇ ).

[0076] In a three-dimensional vector magnetic field, at least three magnetic sensors with a certain angle to each other are required to measure the vector magnetic field. However, it can be foreseen that on this basis, the number of magnetic sensors can be further increased. Correspondingly, in the above calculation process of S11 - S16, the Hall voltage data of the corresponding magnetic sensors need to be incorporated into the analysis process.

[0077] In S13, make the excitation currents of the electromagnets 140 and 150 the same and their magnetic poles in the same direction, and make the excitation currents of the electromagnets 160 and 170 the same and their magnetic poles in the same direction. The excitation currents of the electromagnets 140, 150, 160, 170, and 180 can be traversed in the following way:

[0078] S131: Fix the excitation currents of the electromagnets 160 and 170, and increase the current of the electromagnet 180 from I8min to I8max with a preset step size;

[0079] S132: Increase the excitation currents of the electromagnets 160 and 170 by a preset step size, and perform S131 - S132 again to make the excitation currents of the electromagnets 160 and 170 from I6min to I6max;

[0080] S133: Increase the excitation currents of the electromagnets 140 and 150 by a preset step size, and perform S131 - S133 again to make the excitation currents of the electromagnets 140 and 150 from I4min to I4max.

[0081] Among them, the output signal of the magnetic sensor 200 is in the linear section. For example, the magnetic sensor 200 is a Hall sensor, and the output Hall voltage is in the linear section of the Hall sensor.

[0082] When obtaining the mapping relationship, the signal of the magnetic sensor is subjected to intercept processing, so that the intercept term in the linear relationship of the magnetic sensor signal is 0, thereby completely eliminating the error in the intercept term of the magnetic sensor signal and eliminating the influence of zero drift. Furthermore, when calculating the weak magnetic field, eliminating the intercept term can significantly reduce the proportion of the error value, that is, greatly improve the calculation accuracy in the weak magnetic field. In addition, using the voltage data after intercept processing to calculate the mapping relationship between voltage and magnetic field strength, since the shape and change of the vector magnetic field are relatively complex, the complexity of fitting the voltage of the magnetic sensor with the magnetic field direction and strength at the position to be measured is relatively large. The present invention excludes the intercept term in the relationship between the voltage of the magnetic sensor and the magnetic field from the mapping relationship, reduces the fitting of at least two parameters, can simplify the fitting process of the mapping relationship, reduce the calculation complexity and calculation time, and can quickly complete the fitting of the mapping relationship. Again, the present invention directly fits the signal of the magnetic sensor with the magnetic field at the position to be measured, skips the intermediate calculation process, further reduces the complexity of magnetic field calculation and fitting difficulty, improves the calculation efficiency, and thus reduces the time required for equipment calibration and signal processing during use.

[0083] For the same vector magnetic field generating device, when calculating the magnetic field at different times, since the state of the magnetic sensor itself and the environment it is in may change, therefore, before calculating the magnetic field, it is necessary to correct the magnetic sensor again. Specifically, the correction method is as follows:

[0084] S21: Adjust the vector magnetic field to make the magnetic field strength measured by the magnetic field measuring device 0, and record the output signal of the magnetic sensor;

[0085] S22: According to the output signal of the magnetic sensor when the magnetic field strength at the position to be measured is 0, perform intercept processing on the obtained output signal of the magnetic sensor to obtain the output signal of the magnetic sensor after intercept processing, and use it as the input of the mapping relationship.

[0086] Specifically, in Figure 1 、 Figure 2 shown form,

[0087] S21: Demagnetize the electromagnet to make the magnetic field strength measured by the magnetic field measuring device, i.e., the gaussmeter 300, 0, and record the voltages b 1f 、b 2f of the two Hall sensors after demagnetization is completed;

[0088] S22: Perform intercept processing (V1 - b 1f , V2 - b 2f ) on the obtained Hall voltages (V1, V2) of the Hall sensor, that is, make V1 ＇ = V1 - b 1f 、V2＇ = V2 - b 2f , the Hall voltage (V1 ＇ , V2 ＇ ) after intercept processing is obtained. Substitute (V1 ＇ , V2 ＇ ) into the mapping relationship to calculate the magnetic field at the position to be measured.

[0089] In Figure 3 the form shown,

[0090] S21: Demagnetize the electromagnet so that the magnetic field intensity measured by the magnetic field measuring device, i.e., the gaussmeter 300, is 0, and record the voltages b 1f , b 2f , b 3f of the two Hall sensors after demagnetization is completed;

[0091] S22: Perform intercept processing (V1 - b 1f , V2 - b 2f , V3 - b 3f ) on the Hall voltages (V1, V2, V3) of the obtained Hall sensors, that is, make V1 ＇ = V1 - b 1f , V2 ＇ = V2 - b 2f , V3 ＇ = V3 - b 3f , and the Hall voltages (V1 ＇ , V2 ＇ , V3 ＇ ) after intercept processing are obtained. Substitute (V1 ＇ , V2 ＇ , V3 ＇ ) into the mapping relationship to calculate the magnetic field at the position to be measured.

[0092] By performing the calibration of the magnetic sensor again before calculation, the error of the magnetic sensor is further corrected. In particular, the error of the intercept term in the linear segment of the magnetic sensor is directly eliminated, which can improve the accuracy of vector magnetic field calculation. Especially in the calculation of weak magnetic fields, the accuracy of vector magnetic field calculation can be significantly improved. When combined with the vector magnetic field calculation method of the present invention, by eliminating the error of the intercept term in the linear segment of the magnetic sensor during the fitting and calibration processes, the influence of the intercept term is not included throughout the calculation process of the vector magnetic field, which can improve the accuracy of vector magnetic field calculation, especially the calculation accuracy of weak magnetic fields.

[0093] In addition, the mapping relationship described above can also be a matching relationship between discrete data. Next, taking Figure 3Taking the form shown as an example, the case where the mapping relationship is a matching relationship between discrete data will be described. It can be understood that according to the following description, based on the content recorded in the present invention, it can be extended to Figure 1 , Figure 2 and other related forms of vector magnetic field calculations.

[0094] Figure 3 Figure 8 shows a form of a three-dimensional vector magnetic field. Among them, magnetic sensors 200, such as Hall sensors, are attached to the pole heads 103 of electromagnets 140, 160, and 180; the magnetic field measurement device uses a gaussmeter 300. According to Figure 3 the electromagnet shown, a method for obtaining the mapping relationship in the three-dimensional vector magnetic field will be described:

[0095] In the vector magnetic field, at least two intermediate positions are selected. Here, two intermediate positions are selected, namely the first intermediate position and the second intermediate position;

[0096] For any one of the intermediate positions, the following process is carried out:

[0097] T11: Place the measuring part 301 of the gaussmeter 300 at the first intermediate position in the vector magnetic field, and make the placement direction of the measuring part 301 sensitive to the magnetic field component along the x-axis;

[0098] T12: Traverse the excitation current of the electromagnet at a preset step size, and record the magnetic field value at the measuring part 301 and the Hall voltages (V1, V2, V3) of the corresponding three Hall sensors during the current change process, and save the recorded magnetic field value and the Hall voltages (V1, V2, V3) of the corresponding three Hall sensors;

[0099] T13: Make the placement direction of the measuring part 301 sensitive to the magnetic field component along the y-axis, and carry out T11 - T12 again; make the placement direction of the measuring part 301 sensitive to the magnetic field component along the z-axis, and carry out T11 - T12 again.

[0100] By performing T11 - T14 through two intermediate positions, the corresponding relationships between the magnetic field intensities (H Ax , H Ay , H Az ) in the x, y, and z-axis directions at the first intermediate position A and the Hall voltages (V1, V2, V3) of the three Hall sensors, and the corresponding relationships between the magnetic field intensities (H Bx , H By , H Bz ) in the x, y, and z-axis directions at the second intermediate position B and the Hall voltages (V1, V2, V3) of the three Hall sensors are obtained respectively.

[0101] Next, the calculation of the vector magnetic field will be described.

[0102] The Hall voltage of the collected magnetic sensor 200 is (V 1t , V 2t , V 3t ). In the corresponding relationship obtained in the above steps, search for (V1, V2, V3) that matches (V 1t , V 2t , V 3t ), and then obtain the corresponding (H Ax , H Ay , H Az ), (H Bx , H By , H Bz ); The component of the distance between the first intermediate position A and the second intermediate position B on the x-axis is , the component on the y-axis is , and the component on the z-axis is ; The component of the distance between the position to be measured and the first intermediate position A on the x-axis is , the component on the y-axis is , and the component on the z-axis is , then the magnetic field strength in the upward direction of the x-axis at the position to be measured is ; The magnetic field strength in the upward direction of the y-axis is ; The magnetic field strength in the upward direction of the z-axis is .

[0103] Among them, (V1, V2, V3) that matches (V 1t , V 2t , V 3t ) can be exactly equal, or partially equal and partially similar, or all similar. The specific choice of the approximation degree can be adjusted according to needs. For example, the closest set of data in the recorded corresponding relationship can be used as (V 1t , V 2t , V 3t ) that matches.

[0104] It can be foreseen that when only two magnetic sensors are set, the above mapping relationship and magnetic field calculation can be deformed accordingly. For example, taking the form shown in Figure 2 as an example, magnetic sensors 200, such as Hall sensors, are attached to the pole heads 103 of the electromagnets 110 and 130; the magnetic field measurement device uses a gaussmeter 300. In addition, more than two intermediate positions can be selected, and the magnetic field strength at the position to be measured can be calculated through the positional relationship between multiple intermediate positions and the position to be measured, the signal value output by the current magnetic sensor, and the magnetic field data obtained by searching for the corresponding relationship.

[0105] In the vector magnetic field, at least two intermediate positions are selected. Here, two intermediate positions are chosen, namely the first intermediate position and the second intermediate position;

[0106] For any one of the intermediate positions, the following process is carried out:

[0107] T11: Place the measuring part 301 of the gaussmeter 300 at the first position to be measured in the vector magnetic field, and make the placement direction of the measuring part 301 sensitive to the magnetic field component along the x-axis;

[0108] T12: Traverse the excitation current of the electromagnet in preset step lengths, and record the magnetic field value at the measuring part 301 and the corresponding Hall voltages (V1, V2) of the two Hall sensors during the current change process;

[0109] T13: Make the placement direction of the measuring part 301 sensitive to the magnetic field component along the y-axis, and carry out T11 - T12 again.

[0110] By performing T11 - T13 on the two intermediate positions, the magnetic field strengths (H Ax , H Ay ) in the x and y axis directions at the first intermediate position A and the Hall voltages (V1, V2) of the two Hall sensors, and the magnetic field strengths (H Bx , H By ) in the x and y axis directions at the second intermediate position B and the corresponding relationships between the Hall voltages (V1, V2) of the two Hall sensors are obtained.

[0111] Next, the calculation of the vector magnetic field is described.

[0112] The Hall voltages of the magnetic sensor 200 collected are (V 1t , V 2t ). In the corresponding relationships obtained in the above steps, search for the (V1, V2) that matches (V 1t , V 2t ), and then obtain the corresponding (H Ax , H Ay ), (H Bx , H By ); The component of the distance between the first intermediate position A and the second intermediate position B on the x-axis is , and the component on the y-axis is ; The component of the distance between the position to be measured and the first intermediate position A on the x-axis is , and the component on the y-axis is , then the magnetic field strength in the x-axis upward direction at the position to be measured is ; The magnetic field strength in the y-axis upward direction is .

[0113] Further, when calculating the magnetic field strength, the data with the closest value corresponding to the magnetic sensor is selected from the stored data to participate in the calculation of the magnetic field strength.

[0114] The above content describes the magnetic field calculation in the x-axis and y-axis directions perpendicular to each other. It can be foreseen that the directions of the x-axis and y-axis can be adjusted as needed, for example, making the x-axis and y-axis form an acute angle or an obtuse angle, and the above calculations can still be achieved.

[0115] In the above calculation method, instead of performing function fitting between the magnetic sensor signal and the magnetic field at the point to be measured, data in the database is searched and combined with the position difference at the intermediate position for calculation, without involving function fitting, which greatly saves the time required for function fitting. In addition, the step size of the traversal of the excitation current can be adjusted as needed. For example, when there is sufficient time and high precision requirements, the traversal is performed with a small step size; when time is urgent and general precision requirements are met, the traversal is performed with a larger step size, which can flexibly adjust the balance between the acquisition time and precision of the mapping relationship to meet various detection requirements.

[0116] In addition, the present invention also provides a vector magnetic field calculation system, including: a vector magnetic field module, a magnetic sensor module, and an analysis module. The vector magnetic field module is configured to provide a vector magnetic field, such as Figures 1 to 3 the electromagnet 110-180 shown, and data exchange is performed between the magnetic sensor module and the analysis module. For example, the signal collector 500 and the data analysis device (not shown in the figure) shown in Figures 1 to 2 together serve as the analysis module, or a separate analysis module such as a computer is provided. The magnetic sensor module includes at least two magnetic sensors, and the magnetic sensors are sensitive to the vector magnetic field and the magnetic field sensitive directions form an angle, such as Figures 1 to 3 the magnetic sensor 200 in, and the magnetic field sensitive directions form an angle with each other. The analysis module is configured to be able to output the magnetic field information of the position to be measured according to the data provided by the magnetic sensors. For example, the vector magnetic field calculation method provided by the present invention is run.

[0117] Optionally, the analysis module can also perform correction processing on the output signals of the magnetic sensors. For example, the correction method provided by the present invention is run.

[0118] Again, the present invention also provides a vector magnetic field calculation device, including: an excitation device, a magnetic sensor, an excitation power supply, a sensor power supply, and a data collector. The excitation device includes at least two electromagnets, such as Figures 1 to 3The electromagnets 110 - 180 therein, where an exciting power supply powers the exciting device (not shown in the figure). The magnetic circuits of the electromagnets are arranged at an angle. There are at least two magnetic sensors 200, and the sensitive directions of the magnetic sensors 200 are arranged at an angle and are sensitive to the magnetic field generated by the exciting device. A sensor power supply 400 powers the magnetic sensors 200, and the magnetic sensors 200 are communicatively connected to a signal collector 500. It further includes a data analysis device (not shown in the figure), which is configured to be able to output magnetic field information of a position to be measured according to the data provided by the magnetic sensors 200. For example, the vector magnetic field calculation method provided by the present invention is run. In some cases, the signal collector 500 and the data analysis device can be combined into the same device, such as a data acquisition and analysis device.

[0119] The magnetic sensors 200 are arranged on the magnetic circuits of the electromagnets, and the magnetic sensors 200 are sensitive to the magnetic fields of their respective magnetic circuits. For example, in this application, the magnetic sensors 200 are attached to the magnetic core pole heads 103 of the electromagnets, and can also be arranged on the axial direction of the coils of the electromagnets without magnetic cores, or in other directions that can be sensitive to the magnetic fields at their respective positions.

[0120] The above has shown and described the basic principles, main features and advantages of the present invention. Therefore, the above is only an embodiment of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification is only the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention also includes various equivalent changes and improvements, and these changes and improvements will all fall within the scope of the present invention claimed.

Claims

1. A method for calculating a vector magnetic field, comprising: At least two magnetic sensors are arranged in a vector magnetic field, and the magnetic sensors are sensitive to the vector magnetic field and the magnetic field sensitive directions form an angle; Calculate the magnetic field at the position to be measured according to the mapping relationship between the magnetic sensor and the magnetic field at the position to be measured in the vector magnetic field and the output data of the magnetic sensor; The acquisition method of the mapping relationship includes: S11: Place the measuring part of the magnetic field measuring device at the position to be measured in the vector magnetic field so that the measuring part is sensitive to the vector magnetic field; S12: Adjust the vector magnetic field so that the magnetic field intensity measured by the magnetic field measuring device is 0, and record the output signal of the magnetic sensor; S13: Change the vector magnetic field, and record the data measured by the magnetic field measuring device during the change process and the corresponding output signal of the magnetic sensor; S14: According to the output signal of the magnetic sensor when the magnetic field intensity at the position to be measured is 0, perform intercept processing on the obtained output signal of the magnetic sensor to obtain the output signal of the magnetic sensor after intercept processing; S15: Based on the output signal of the magnetic sensor after intercept processing and the data measured by the magnetic field measuring device, obtain the mapping relationship between the magnetic sensor and the magnetic field at the position to be measured in the vector magnetic field; The acquisition method of the mapping relationship further includes: T11: Place the measuring part of the magnetic field measuring device at at least two intermediate positions of the vector magnetic field so that the measuring part is sensitive to the vector magnetic field, and the position to be measured is located between the two intermediate positions; T12: Change the vector magnetic field, and record the data measured by the magnetic field measuring device during the change process and the corresponding output signal of the magnetic sensor; When calculating the magnetic field at the position to be measured, the position relationship between the position to be measured and the intermediate position is also used.

2. The method for calculating a vector magnetic field according to claim 1, characterized in that: In S11, the measuring part is sensitive to one component of the vector magnetic field; the acquisition method of the mapping relationship further includes: S16: Make the measuring part sensitive to other components of the vector magnetic field, and perform S12 - S15 again respectively.

3. The method for calculating a vector magnetic field according to claim 1, characterized in that: The output signal of the magnetic sensor is in the linear segment.

4. The method for calculating a vector magnetic field according to claim 1, characterized in that: The vector magnetic field is provided by an electromagnet; in S12, the magnetic field intensity measured by the magnetic field measuring device is made 0 through oscillating demagnetization.

5. The method for calculating a vector magnetic field according to claim 4, characterized in that: The current waveform of the oscillating demagnetization is at least one of a square wave, a triangular wave, and a sine wave.

6. The method for calculating a vector magnetic field according to claim 1, characterized in that: The vector magnetic field is provided by an electromagnet; in S13, the vector magnetic field is changed by traversing the excitation current of the electromagnet.

7. The method for calculating a vector magnetic field according to claim 6, characterized in that: Traverse the excitation current with a preset step size.

8. The method for calculating a vector magnetic field according to claim 1, characterized in that: Before calculating the magnetic field at the position to be measured, correct the magnetic sensor.

9. The method for calculating a vector magnetic field according to claim 8, characterized in that: The correction method includes: S21: Adjust the vector magnetic field so that the magnetic field intensity measured by the magnetic field measuring device is 0, and record the output signal of the magnetic sensor; S22: According to the output signal of the magnetic sensor when the magnetic field intensity at the position to be measured is 0, perform intercept processing on the obtained output signal of the magnetic sensor to obtain the output signal of the magnetic sensor after intercept processing, as the input of the mapping relationship.

10. A vector magnetic field calculation system, characterized in that: Includes: A vector magnetic field module, a magnetic sensor module, and an analysis module. The vector magnetic field module is configured to provide a vector magnetic field. Data exchange occurs between the magnetic sensor module and the analysis module. The magnetic sensor module includes at least two magnetic sensors, and the magnetic sensors are sensitive to the vector magnetic field and the magnetic field sensitive directions form an angle. The analysis module is configured to be able to run the vector magnetic field calculation method according to any one of claims 1-9 to output the magnetic field information of the position to be measured based on the data provided by the magnetic sensors.

11. The vector magnetic field calculation system according to claim 10, characterized in that: The analysis module is also capable of correcting the output signals of the magnetic sensors.

12. A vector magnetic field calculation device, comprising: An excitation device, magnetic sensors, an excitation power supply, a sensor power supply, a data collector, and a data analysis device. The excitation device includes at least two electromagnets. The excitation power supply supplies power to the excitation device. The magnetic circuits of the electromagnets are arranged at an angle. There are at least two magnetic sensors, and the sensitive directions of the magnetic sensors are arranged at an angle and are sensitive to the magnetic field generated by the excitation device. The sensor power supply supplies power to the magnetic sensors. The magnetic sensors are communicatively connected to the data collector. The data analysis device is configured to be able to run in the form of the vector magnetic field calculation method according to any one of claims 1-9.

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