A device and method for measuring the distortion of the pulsed magnetic field of an impact magnet

Abstract

The application discloses a device for measuring the magnetic field distortion of a pulsed magnet, which comprises an arrayed measuring coil assembly and an analog integrator; the arrayed measuring coil assembly comprises multiple layers of PCB circuit boards which are placed in an upper-lower overlapping mode; each layer of the PCB circuit boards is engraved with N groups of coils which cover the field region of the pulsed magnet; the coils of different layers of the PCB circuit boards adopt the same spiral direction and are connected with each other through through holes; the analog integrator comprises a primary signal integrator for processing an induced voltage primary signal and a differential signal integrator for processing a differential signal; a single coil signal is connected to the primary signal integrator; the wires of different groups are reversely connected with each other, and the differential signal is connected to the differential integrator; and a corresponding measuring method is also disclosed.

Description

Technical Field

[0001] This invention belongs to the field of magnetic field distortion measurement, specifically relating to a device and method for measuring the magnetic field distortion of an impact magnet pulse. Background Technology

[0002] An impact magnet is a magnet that is excited by an electric current and whose magnetic field exhibits pulse characteristics in the time dimension during operation. It is widely used in various accelerator beam transport lines. By periodically switching on the current through the impact magnet, a pulsed magnetic field is generated, which deflects the beam particles accordingly, thereby realizing the switching function of the beam transport line.

[0003] During the process of exciting a pulsed magnetic field by an impact magnet, the current can reach hundreds of amperes, and the current rise time is on the scale of a few microseconds to hundreds of microseconds. Therefore, the law of electromagnetic induction will cause the magnetic field excitation to lag behind the current rise, thus producing distortion of the magnetic field on both time and space scales, which will affect the function of the impact magnet in deflecting particles. Therefore, it is necessary to measure and study the magnetic field distortion during the current rise process.

[0004] Because the rise time of the impact magnet is short and the peak current is large, there are certain differences in the waveform and amplitude of the excitation current between different pulses. Its repeatability is difficult to meet the requirements of distortion measurement. Therefore, it is necessary to measure the distortion of the pulse magnetic field within a single current pulse to reduce the influence of the excitation current repeatability on the results. In the existing technology, there is still a lack of a device that can measure the distortion of the pulse magnetic field of the impact magnet. In addition, the problem of error accumulation and difficulty in elimination caused by multiple acquisitions of digital signals and discrete summation is also present. Summary of the Invention

[0005] To address the deficiencies or problems existing in the prior art, this invention provides a device and method for measuring the distortion of the pulsed magnetic field of an impact magnet; by connecting different coils in reverse and integrating their differential signals, a refined representation of the magnetic field differences at different locations can be achieved, and finally, the influence of magnetic field distortion on the pulsed magnetic field excitation can be analyzed.

[0006] The technical solution adopted in this invention is: a device for measuring the pulse magnetic field distortion of an impact magnet, comprising an array-type measuring coil assembly and an analog integrator; the array-type measuring coil comprises multiple layers of PCB circuit boards stacked vertically; each layer of PCB circuit board is etched with N groups of coils covering the good field area of ​​the impact magnet, where 9≥N≥5, the coils of different layers of PCB circuit boards adopt the same helical direction, and the coils of different layers are connected through through holes; the analog integrator is a primary signal integrator for processing the original induced voltage signal and a differential signal integrator for processing the differential signal, the signal of a single coil is connected to the primary signal integrator, and the different groups of wires are connected in reverse so that their signals are differentially divided before being connected to the differential integrator.

[0007] Furthermore, the number of the multi-layered, overlapping PCB circuit boards is 5-10.

[0008] Furthermore, all of the analog integrators are RC integrators.

[0009] Furthermore, the N sets of coils etched on each PCB layer are arranged at equal intervals.

[0010] Furthermore, the coil lead-out method adopts a scheme in which two wires are arranged in overlapping layers.

[0011] Furthermore, the analog integrator employs balancing resistors to reduce the impact of zero drift in the operational amplifier.

[0012] Furthermore, the analog integrator uses a zero-drift adjustment sliding resistor to manually adjust the noise amplification effect on zero drift.

[0013] Furthermore, the RC integrator includes an input resistor, a bridging capacitor, a balancing resistor, an operational amplifier, and a zero-drift adjustment sliding resistor; the zero-drift adjustment sliding resistor is used to adjust the zero drift of the operational amplifier, especially for differential signal integrators with larger amplification factors, and the resistance value is preferably in the range of 0-1MΩ.

[0014] As another aspect of the present invention, a method for measuring the distortion of the pulse magnetic field of an impact magnet is also disclosed, comprising the following steps:

[0015] (1) Set up the experimental platform: fix the impact magnet and the stepper motor on the experimental platform, fix the multi-layer PCB circuit board stacked on top of the stepper motor, connect N sets of coils to the analog integrator, and turn on the power of the analog integrator; the signal of a single coil is connected to the original signal integrator, and the original signal of the pulse magnetic field is obtained after integration. The different sets of wires are connected in reverse so that their signals are differentially connected to the differential integrator.

[0016] (2) The impact magnet power cabinet triggers the signal, and the pulse current excites the pulse magnetic field;

[0017] (3) The measuring coil generates an induced voltage, and the original signal and differential signal of the induced voltage are respectively input to the original signal integrator and the differential signal integrator;

[0018] (4) After the original signal integrator and the differential signal integrator complete the integration of the induced voltage, the waveform and amplitude of the output voltage are measured by the oscilloscope to obtain the differential signal at different positions of the pulse magnetic field. By comparing the current signal, the original magnetic field signal and the differential magnetic field signal, the magnetic field distortion of the impact magnet in time and space is obtained to evaluate the magnetic field distortion.

[0019] In summary, compared with the prior art, the above-described technical solutions conceived by this invention can achieve the following beneficial effects:

[0020] (1) The device for measuring the magnetic field distortion of an impact magnet pulse provided by the present invention can better evaluate the magnetic field distortion. By reversing the coils at different positions (equivalent to taking the difference of the signal), the difference between the two can be obtained directly in one measurement, without having to record the difference in two separate measurements. This avoids the problem of error accumulation and difficulty in elimination caused by multiple acquisitions of digital signals for discrete summation (its zero drift is negligible relative to the measurement signal itself).

[0021] (2) The device for measuring the pulse magnetic field distortion of an impact magnet provided by the present invention connects different coils in reverse and integrates their differential signals to achieve a refined display of the magnetic field differences at different positions, and finally analyzes the influence of magnetic field distortion on pulse magnetic field excitation. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of an embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram of the pulse magnetic field distortion measurement device in an embodiment of the present invention;

[0024] Figure 3 This is a circuit design diagram of the analog integrator in an embodiment of the present invention;

[0025] Figure 4 The waveforms of the induced voltage signal and the integrated voltage signal are shown in the embodiments of the present invention. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0027] Please refer to Figures 1-3 A device for measuring the distortion of a pulsed magnetic field of an impact magnet includes an array of measuring coils and an analog integrator. The array of measuring coils comprises multiple layers of overlapping PCB circuit boards; the multi-layer design increases the induced voltage generated by the pulsed magnetic field. Each PCB circuit board is etched with N groups of coils covering the good field region of the impact magnet (the good field region refers to the area where the magnetic field distribution meets the design requirements (non-uniformity less than 1%), which is the main location where the impact magnet functions), where 9 ≥ N ≥ 5. Figure 1In this preferred scheme, N is set to 7. The 7 groups represent a trade-off between two conditions: the spacing between coils cannot be too large (otherwise, there won't be enough sampling locations to represent the field well), nor can it be too small (otherwise, the signal amplitude will be too small, making it more sensitive to noise). Coils on different PCB layers use the same helical direction and are connected between coils on different layers via copper vias. The analog integrator consists of a primary signal integrator for processing the original induced voltage signal and a differential signal integrator for processing the differential signal. A single coil signal is input to the primary signal integrator, and after integration, the original signal of the pulsed magnetic field is obtained. Different groups of wires are connected in reverse to differentiate their signals before inputting them to the differential integrator. After integration, the differential signal at different positions of the pulsed magnetic field is obtained. By comparing the current signal, the original magnetic field signal, and the differential magnetic field signal, the magnetic field distortion of the impact magnet on both temporal and spatial scales is obtained. For example, by connecting the coil 4 at the middle position in reverse with the other coils, the difference in induced voltage signal between a specific position and the center position under a pulsed magnetic field can be obtained. The specific connection method is as follows: the array coil is led out through the pin and connected to the input terminal of the original signal integrator, and at the same time, it is connected in reverse with the center coil and connected to the input terminal of the differential signal integrator.

[0028] The following example illustrates the reverse connection described above. For instance, the positive terminals of coils A and B are connected together, and their negative terminals are connected together. After this series connection, if coil A generates 5V and coil B generates 4V, the signal after the reverse connection will be the difference of 1V between them.

[0029] To prevent the voltage amplitude from being too small after integration of a differential signal with a small amplitude, making it difficult to measure accurately, its time constant should be more than two orders of magnitude smaller than that of the original signal integrator. Preferably, the parameters of the original signal integrator are input resistance R = 1000Ω and bridging capacitor C = 1μF, and the parameters of the differential signal integrator are input resistance R = 100Ω and bridging capacitor C = 0.02μF.

[0030] As a preferred embodiment, the number of PCB circuit boards stacked on top of each other in the multi-layered arrangement is 5-10.

[0031] All analog integrators are RC integrators. They include an input resistor, a bridging capacitor, a balancing resistor, an operational amplifier, and a zero-drift adjustment sliding resistor. The input resistor and bridging capacitor are the main functional components of the RC integrator, realizing the integration function of the input induced voltage signal. For the original signal integrator, R = 1000Ω and C = 1μF are preferred; for the differential signal integrator, R = 100Ω and C = 0.02μF are preferred. The operational amplifier is powered by a battery to ensure stable power supply voltage and improve integration accuracy.

[0032] The analog integrator uses balancing resistors to reduce the impact of zero drift in the operational amplifier.

[0033] The analog integrator uses a zero-drift adjustment sliding resistor to manually adjust the noise amplification effect on zero drift.

[0034] The balancing resistor is used to balance the zero-point drift of the operational amplifier, so its resistance value is the same as the input resistance, and Ro = 100Ω is selected. The operational amplifier is the OPA192 precision operational amplifier manufactured by Texas Instruments, which features low offset voltage, low bias current, and low noise.

[0035] As a preferred option, N sets of coils are equidistantly arranged on each PCB board layer, with a coil wire width of 0.1mm, a measuring coil length of 20mm, and a width of 10mm.

[0036] As a preferred option, after the coil is led out, two wires are arranged overlapping in different layers (see reference). Figure 1 (Note) to avoid the induced voltage at other locations affecting the coil terminal voltage.

[0037] The RC integrator includes an input resistor, a bridging capacitor, a balancing resistor, an operational amplifier, and a zero-drift adjustment sliding resistor. The zero-drift adjustment sliding resistor is used to adjust the zero drift of the operational amplifier, especially for differential signal integrators with larger amplification factors, and the resistance value is preferably in the range of 0-1MΩ.

[0038] As another aspect of the present invention, based on the above-described device for measuring the pulse magnetic field distortion of an impact magnet, a method for measuring the pulse magnetic field distortion of an impact magnet is also provided, comprising the following steps:

[0039] (1) Set up the experimental platform: fix the impact magnet and the stepper motor on the experimental platform, fix the multi-layer PCB circuit board stacked on top of the stepper motor, connect N sets of coils to the analog integrator, and turn on the power of the analog integrator; the signal of a single coil is connected to the original signal integrator, and the original signal of the pulse magnetic field is obtained after integration. The different sets of wires are connected in reverse so that their signals are differentially connected to the differential integrator.

[0040] (2) The impact magnet power cabinet triggers the signal, and the pulse current excites the pulse magnetic field;

[0041] (3) The measuring coil generates an induced voltage, and the original signal and differential signal of the induced voltage are respectively input to the original signal integrator and the differential signal integrator;

[0042] (4) After the original signal integrator and the differential signal integrator complete the integration of the induced voltage, the waveform and amplitude of the output voltage are measured by the oscilloscope to obtain the differential signal at different positions of the pulse magnetic field. By comparing the current signal, the original magnetic field signal and the differential magnetic field signal, the magnetic field distortion of the impact magnet in time and space is obtained to evaluate the magnetic field distortion.

[0043] The results are as follows Figure 4 As shown in the figure, it can be seen that the device for measuring the pulse magnetic field distortion of the impact magnet of this application can eliminate the effect of operational amplifier zero drift accumulation.

[0044] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the structural relationships and principles of the invention. Various changes and modifications can be made to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed.

Claims

1. A device for measuring the distortion of a pulsed magnetic field from an impact magnet, characterized in that, The system includes an array-type measuring coil assembly and an analog integrator. The array-type measuring coil comprises multiple layers of PCB circuit boards stacked vertically. The multi-layer design increases the induced voltage generated by the pulsed magnetic field. Each PCB circuit board has N sets of coils etched to cover the good field range of the impact magnet, where 9 ≥ N ≥ 5. The coils on different PCB circuit boards use the same helical direction and are connected between coils on different layers through through-holes. The analog integrator is a primary signal integrator for processing the original induced voltage signal and a differential signal integrator for processing the differential signal. The signal of a single coil is connected to the primary signal integrator, and the different sets of wires are connected in reverse to make their signals differential before being connected to the differential integrator. The N sets of coils etched on each PCB circuit board are arranged at equal intervals. After the coils are led out, two wires are arranged in overlapping layers.

2. The device for measuring the pulse magnetic field distortion of an impact magnet according to claim 1, characterized in that: The number of PCB circuit boards stacked on top of each other in the multi-layered arrangement is 5 to 10.

3. The device for measuring the pulse magnetic field distortion of an impact magnet according to claim 1, characterized in that: All the analog integrators used are RC integrators.

4. The device for measuring the pulse magnetic field distortion of an impact magnet according to claim 1, characterized in that: The analog integrator uses balancing resistors to reduce the impact of zero drift in the operational amplifier.

5. The device for measuring the pulse magnetic field distortion of an impact magnet according to claim 1, characterized in that: The analog integrator uses a zero-drift adjustment sliding resistor to manually adjust the noise amplification effect on zero drift.

6. The device for measuring the pulse magnetic field distortion of an impact magnet according to claim 3, characterized in that: The RC integrator includes an input resistor, a bridging capacitor, a balancing resistor, an operational amplifier, and a zero-drift adjustable sliding resistor; The zero-drift adjustment sliding resistor is used to adjust the zero drift of the operational amplifier. For differential signal integrators with larger amplification factors, the resistance range is 0-1MΩ.

7. The measurement method of the device for measuring the pulse magnetic field distortion of an impact magnet according to claim 1, characterized in that: The steps include the following: (1) Set up the experimental platform: fix the impact magnet and the stepper motor on the experimental platform, fix the multi-layer PCB circuit board stacked on top of the stepper motor, connect N sets of coils to the analog integrator, and turn on the power of the analog integrator; the signal of a single coil is connected to the original signal integrator, and the original signal of the pulse magnetic field is obtained after integration. The different sets of wires are connected in reverse so that their signals are differentially connected to the differential integrator. (2) The impact magnet power cabinet triggers the signal, and the pulse current excites the pulse magnetic field; (3) The measuring coil generates an induced voltage, and the original signal and differential signal of the induced voltage are respectively input to the original signal integrator and the differential signal integrator; (4) After the original signal integrator and the differential signal integrator complete the integration of the induced voltage, the waveform and amplitude of the output voltage are measured by the oscilloscope to obtain the differential signal at different positions of the pulse magnetic field. By comparing the current signal, the original magnetic field signal and the differential magnetic field signal, the magnetic field distortion of the impact magnet in time and space is obtained to evaluate the magnetic field distortion.

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