A method for detecting a quench of a low-temperature superconducting magnet based on a strain signal

Abstract

The application provides a low-temperature superconducting magnet quench detection method based on strain signals, which uses the strain signal data of the superconducting magnet in a preset time period before the detection time to obtain a first determination time and a second determination time in sequence through serial logic, and judges whether the superconducting magnet quenches according to the first determination time and the second determination time, and obtains the quench time of the superconducting magnet in the case of quenching of the superconducting magnet. Through the measurement of physical signals, the application can realize quench detection of multi-coil superconducting magnets and single-coil superconducting magnets, avoid measurement delay, improve detection speed, reduce detection cost and space requirements of detection sensors, and meanwhile, physical signal acquisition and transmission are more reliable, applicable to long-distance transmission, and remote control can be realized. The application can solve the technical problem that the existing superconducting magnet quench detection method cannot detect the quench time of the magnet in time.

Description

Technical Field

[0001] This invention relates to the field of quench detection technology for low-temperature superconducting magnets, and in particular to a method for quench detection of low-temperature superconducting magnets based on strain signals. Background Technology

[0002] Superconducting wires made of cryogenic metals exhibit zero resistance under extremely low temperatures, playing a crucial role in technical and engineering applications requiring high current and strong magnetic fields. By applying high-current excitation to a superconducting coil wound from superconducting wires, a superconducting magnet with strong magnetic field properties can be obtained.

[0003] Superconducting magnets, with their ability to provide strong magnetic fields and forces, have been widely used in medical equipment, maglev transportation, and military applications. Superconducting magnets used in maglev transportation often operate in highly dynamic environments with strong vibrations and high electromagnetic excitation. High-dynamic superconducting magnets are inherently prone to quenching risks. Once a superconducting magnet quenches, it loses its superconducting state and its strong electromagnetic force, severely impacting the stable operation of itself and surrounding equipment. Therefore, effectively and rapidly detecting the quenching moment of a high-dynamic single-coil cryogenic superconducting magnet and quickly shutting down the operating equipment is crucial for the safe operation of the equipment.

[0004] Currently, there are three main methods for measuring the quench in superconducting magnets:

[0005] (1) Voltage measurement of superconducting magnets: When a superconducting magnet loses quench, its quench voltage can be measured. Therefore, it can be determined whether it has lost quench by voltage measurement.

[0006] (2) Magnetic field measurement of superconducting magnets: After a superconducting magnet loses quench, the strong magnetic field it generates will drop rapidly. Therefore, magnetic field measurement can be used to determine whether it has lost quench.

[0007] (3) Temperature measurement of the superconducting magnet. When the superconducting magnet loses quench, it will release energy and generate a lot of heat, and the coil temperature will rise significantly. Thus, the temperature can be used to determine whether the coil has lost quench.

[0008] However, all three methods mentioned above have certain limitations, as they cannot detect the quenching moment of the superconducting magnet in a timely manner. The specific drawbacks are as follows:

[0009] (1) Voltage measurement

[0010] Voltage measurement methods can quickly detect quench voltage in superconducting magnets with multiple coils connected in series. However, for single-coil superconducting magnets, because the voltage signal line is short-circuited by the superconducting switch, the quench voltage can only be detected after the quench point is transmitted to the superconducting switch and the switch is also in a quench state. Therefore, for highly dynamic single-coil superconducting magnets, voltage signal measurement is sometimes untimely or even fails to detect quench voltage.

[0011] (2) Magnetic field measurement

[0012] Magnetic field measurement methods can meet the quench detection requirements of most superconducting magnets. However, for highly dynamic superconducting magnets, there is often limited space outside the magnet to install Hall sensors, transmitters, and their signal transmission cables. In addition, after a superconducting magnet loses quench, its magnetic field decreases slowly in the initial stage, which cannot adequately meet the requirements for rapid and timely quench detection.

[0013] (3) Temperature measurement

[0014] Temperature measurement is unaffected by whether the superconducting magnet is a single coil or whether it is in a high-dynamic environment. However, temperature measurement has two drawbacks: First, quenching of a superconducting magnet is often triggered by a single point and then spreads to the entire coil. Temperature measurement can only measure a few points on the magnet. Therefore, when the superconducting magnet coil quenches at a location far from the temperature measurement point, the temperature measurement method has very poor timeliness for quench detection. Second, the temperature sensor is bonded to the superconducting coil. The temperature rise of the superconducting coil after the superconducting magnet quenches, the temperature conduction to the temperature sensor, and the temperature sensor's measurement sensitivity all have a certain delay, which also leads to poor timeliness of temperature measurement. Summary of the Invention

[0015] This invention provides a method for detecting quenching in low-temperature superconducting magnets based on strain signals, which can solve the technical problem that existing superconducting magnet quenching detection methods cannot detect the moment of quenching in a timely manner.

[0016] According to one aspect of the present invention, a method for detecting quenching in a low-temperature superconducting magnet based on strain signals is provided, the method comprising:

[0017] S10, at the current time T i As the detection time;

[0018] S20. Acquire strain signal data of the superconducting magnet within a preset time period before the detection time;

[0019] S30. Based on the strain signal data of the superconducting magnet within a preset time period before the detection time, obtain the frequency components of the superconducting magnet at each moment within the preset time period before the detection time.

[0020] S40. Calculate the energy of the superconducting magnet at each time point whose frequency is less than the preset frequency, and obtain the ratio of the energy of the superconducting magnet at each time point whose frequency is less than the preset frequency to the total energy of all frequencies in the superconducting magnet at the corresponding time point.

[0021] S50. Determine whether there is at least one ratio greater than a preset percentage among the ratios of the energy with frequencies lower than a preset frequency in the frequency components of the superconducting magnet at each time point to the total energy of all frequencies in the frequency components of the superconducting magnet at the corresponding time point. If so, if there is only one ratio greater than the preset percentage, then the time T corresponding to the ratio greater than the preset percentage is... k As the first determination time, if there are multiple ratios greater than a preset percentage, the earliest time T among the multiple times corresponding to the multiple ratios greater than the preset percentage is selected. k This is the first decision point, and the process proceeds to S60; otherwise, the next decision point is T. i+1 As the detection point, proceed to S20;

[0022] S60. Perform low-pass filtering on the strain signal data of the superconducting magnet within a preset time period before the detection time to obtain the low-pass filtered signal of the superconducting magnet.

[0023] S70. Obtain the maximum value and root mean square of the low-pass filtered signal of the superconducting magnet;

[0024] S80. Determine whether the ratio of the maximum value to the root mean square of the low-pass filter signal of the superconducting magnet is greater than or equal to a preset threshold. If so, set the time T corresponding to the maximum value of the low-pass filter signal of the superconducting magnet to... j As the second decision point, proceed to S90; otherwise, proceed to the next decision point T. i+1 As the detection point, proceed to S20;

[0025] S90. Determine whether the absolute value of the difference between the first determination time and the second determination time is less than a preset time. If so, determine that the superconducting magnet has lost quench, and obtain the quench time of the superconducting magnet based on the first determination time and the second determination time. Otherwise, proceed to the next time T. i+1 As the detection point, proceed to S20.

[0026] Preferably, in S20, acquiring the strain signal data of the superconducting magnet within a preset time period before the detection time includes: acquiring the strain signal data from T... i -△T time to T i The strain signal data of the superconducting magnet within a time period, wherein the value of ΔT ranges from 10 to 50 ms.

[0027] Preferably, in S30, obtaining the frequency components of the superconducting magnet at each moment within the preset time period before the detection time based on the strain signal data of the superconducting magnet within the preset time period before the detection time includes: performing discrete wavelet transform on the strain signal data of the superconducting magnet within the preset time period before the detection time to obtain the frequency components of the superconducting magnet at each moment within the preset time period before the detection time.

[0028] Preferably, in S90, the quenching time of the superconducting magnet is obtained by the following formula:

[0029] T Qch =(T k +T j ) / 2;

[0030] In the formula, T Qch T is the quench moment of the superconducting magnet. k For the first decision moment, T j This is the second decision-making moment;

[0031] In S90, the preset time ranges from 50 to 100 µs.

[0032] Preferably, in S40, the preset frequency ranges from 10 to 50 Hz; in S50, the preset percentage ranges from 50 to 90%; and in S80, the preset threshold ranges from 10 to 20.

[0033] According to another aspect of the present invention, a method for detecting quenching in a low-temperature superconducting magnet based on strain signals is provided, the method comprising:

[0034] S10, at the current time T i As the detection time;

[0035] S20. Acquire strain signal data of the superconducting magnet within a preset time period before the detection time;

[0036] S30. Perform low-pass filtering on the strain signal data of the superconducting magnet within a preset time period before the detection time to obtain the low-pass filtered signal of the superconducting magnet.

[0037] S40. Obtain the maximum value and root mean square of the low-pass filtered signal of the superconducting magnet;

[0038] S50. Determine whether the ratio of the maximum value to the root mean square of the low-pass filter signal of the superconducting magnet is greater than or equal to a preset threshold. If so, set the time T corresponding to the maximum value of the low-pass filter signal of the superconducting magnet to... j As the second decision point, proceed to S60; otherwise, proceed to the next decision point T. i+1 As the detection point, proceed to S20;

[0039] S60. Based on the strain signal data of the superconducting magnet within a preset time period before the detection time, obtain the frequency components of the superconducting magnet at each moment within the preset time period before the detection time.

[0040] S70. Calculate the energy with a frequency lower than the preset frequency in the frequency components of the superconducting magnet at each time moment, and obtain the ratio of the energy with a frequency lower than the preset frequency in the frequency components of the superconducting magnet at each time moment to the total energy of all frequencies in the frequency components of the superconducting magnet at the corresponding time moment.

[0041] S80. Determine whether there is at least one ratio greater than a preset percentage among the ratios of the energy with frequencies lower than a preset frequency in the frequency components of the superconducting magnet at each time point to the total energy of all frequencies in the frequency components of the superconducting magnet at the corresponding time point. If so, if there is only one ratio greater than the preset percentage, then the time T corresponding to the ratio greater than the preset percentage is... k As the first determination time, if there are multiple ratios greater than a preset percentage, the earliest time T among the multiple times corresponding to the multiple ratios greater than the preset percentage is selected. k This is the first decision point, and the process proceeds to S90; otherwise, the next decision point is T. i+1 As the detection point, proceed to S20;

[0042] S90. Determine whether the absolute value of the difference between the first determination time and the second determination time is less than a preset time. If so, determine that the superconducting magnet has lost quench, and obtain the quench time of the superconducting magnet based on the first determination time and the second determination time. Otherwise, proceed to the next time T. i+1 As the detection point, proceed to S20.

[0043] Preferably, in S20, acquiring the strain signal data of the superconducting magnet within a preset time period before the detection time includes: acquiring the strain signal data from T... i -△T time to T i The strain signal data of the superconducting magnet within a time period, wherein the value of ΔT ranges from 10 to 50 ms.

[0044] Preferably, in S60, obtaining the frequency components of the superconducting magnet at each moment within the preset time period before the detection time based on the strain signal data of the superconducting magnet within the preset time period before the detection time includes: performing discrete wavelet transform on the strain signal data of the superconducting magnet within the preset time period before the detection time to obtain the frequency components of the superconducting magnet at each moment within the preset time period before the detection time.

[0045] Preferably, in S90, the quenching time of the superconducting magnet is obtained by the following formula:

[0046] TQch =(T k +T j ) / 2;

[0047] In the formula, T Qch T is the quench moment of the superconducting magnet. k For the first decision moment, T j This is the second decision-making moment;

[0048] In S90, the preset time ranges from 50 to 100 µs.

[0049] Preferably, in S50, the preset threshold value ranges from 10 to 20; in S70, the preset frequency value ranges from 10 to 50 Hz; and in S80, the preset percentage value ranges from 50 to 90%.

[0050] By applying the technical solution of this invention, strain signal data of a superconducting magnet within a preset time period before the detection time is used to sequentially acquire a first determination time and a second determination time through serial logic. The invention then determines whether the superconducting magnet has lost quench based on these two determination times, and if so, acquires the quench time. This invention, through the measurement of physical signals, can detect quench failure in both multi-coil and single-coil superconducting magnets, avoiding measurement delays, increasing detection speed, reducing detection costs and sensor space requirements, and is applicable to small or compact superconducting magnets. Furthermore, the physical signal acquisition and transmission are more reliable, enabling long-distance transmission and remote control. The use of serial logic to sequentially acquire the first and second determination times improves detection accuracy. Attached Figure Description

[0051] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the embodiments of the invention and illustrate the principles of the invention together with the textual description. It is obvious that the drawings described below are merely some embodiments of the invention, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0052] Figure 1 A flowchart of a low-temperature superconducting magnet quench detection method based on strain signals according to an embodiment of the present invention is shown;

[0053] Figure 2 A flowchart of a low-temperature superconducting magnet quench detection method based on strain signals according to another embodiment of the present invention is shown;

[0054] Figure 3A schematic diagram of a low-temperature superconducting magnet quench detection method based on strain signals according to an embodiment of the present invention is shown. Detailed Implementation

[0055] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0056] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0057] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0058] like Figure 1 As shown, this invention provides a method for detecting quenching in low-temperature superconducting magnets based on strain signals, the method comprising:

[0059] S10, at the current time T i As the detection time;

[0060] S20. Acquire strain signal data of the superconducting magnet within a preset time period before the detection time;

[0061] S30. Based on the strain signal data of the superconducting magnet within a preset time period before the detection time, obtain the frequency components of the superconducting magnet at each moment within the preset time period before the detection time.

[0062] S40. Calculate the energy of the superconducting magnet at each time point whose frequency is less than the preset frequency, and obtain the ratio of the energy of the superconducting magnet at each time point whose frequency is less than the preset frequency to the total energy of all frequencies in the superconducting magnet at the corresponding time point.

[0063] S50. Determine whether there is at least one ratio greater than a preset percentage among the ratios of the energy with frequencies lower than a preset frequency in the frequency components of the superconducting magnet at each time point to the total energy of all frequencies in the frequency components of the superconducting magnet at the corresponding time point. If so, if there is only one ratio greater than the preset percentage, then the time T corresponding to the ratio greater than the preset percentage is... k As the first determination time, if there are multiple ratios greater than a preset percentage, the earliest time T among the multiple times corresponding to the multiple ratios greater than the preset percentage is selected. k As the first decision moment, proceed to S60; otherwise, proceed to the next moment T. i+1 As the detection point, proceed to S20;

[0064] S60. Perform low-pass filtering on the strain signal data of the superconducting magnet within a preset time period before the detection time to obtain the low-pass filtered signal of the superconducting magnet.

[0065] S70. Obtain the maximum value and root mean square of the low-pass filtered signal of the superconducting magnet;

[0066] S80. Determine whether the ratio of the maximum value to the root mean square of the low-pass filter signal of the superconducting magnet is greater than or equal to a preset threshold. If so, set the time T corresponding to the maximum value of the low-pass filter signal of the superconducting magnet to... j As the second decision point, proceed to S90; otherwise, proceed to the next decision point T. i+1 As the detection point, proceed to S20;

[0067] S90. Determine whether the absolute value of the difference between the first determination time and the second determination time is less than a preset time. If so, determine that the superconducting magnet has lost quench, and obtain the quench time of the superconducting magnet based on the first determination time and the second determination time. Otherwise, proceed to the next time T. i+1 As the detection point, proceed to S20.

[0068] This invention utilizes strain signal data from a superconducting magnet within a preset time period prior to the detection time to sequentially acquire a first determination time and a second determination time via serial logic. Based on these two determination times, it determines whether the superconducting magnet has lost quench. If the superconducting magnet has lost quench, it acquires the quench time. This invention, through the measurement of physical signals, can detect quench in both multi-coil and single-coil superconducting magnets, avoiding measurement delays, increasing detection speed, reducing detection costs and sensor space requirements, and is applicable to small or compact superconducting magnets. Furthermore, the physical signal acquisition and transmission are more reliable, suitable for long-distance transmission and remote control. The use of serial logic to sequentially acquire the first and second determination times improves detection accuracy.

[0069] According to one embodiment of the present invention, in S20, acquiring strain signal data of the superconducting magnet within a preset time period prior to the detection time includes: acquiring strain signal data from T... i -△T time to T i The strain signal data of the superconducting magnet within a time period, wherein the value of ΔT ranges from 10 to 50 ms.

[0070] By setting the range of values ​​for △T as described above, we avoid inaccurate measurement results due to excessively large values, and also avoid reduced measurement speed due to excessively small values.

[0071] According to an embodiment of the present invention, in S30, obtaining the frequency components of the superconducting magnet corresponding to each moment within the preset time period before the detection time based on the strain signal data of the superconducting magnet within the preset time period before the detection time includes: performing discrete wavelet transform on the strain signal data of the superconducting magnet within the preset time period before the detection time to obtain the frequency components of the superconducting magnet corresponding to each moment within the preset time period before the detection time.

[0072] According to one embodiment of the present invention, in S40, the preset frequency ranges from 10 to 50 Hz. In S40, if one frequency in the frequency components of the superconducting magnet at each moment is less than the preset frequency, the ratio of the energy corresponding to that frequency to the total energy of all frequencies is obtained; if multiple frequencies in the frequency components of the superconducting magnet at each moment are less than the preset frequency, the ratio of the energy corresponding to each frequency less than the preset frequency to the total energy of all frequencies is obtained.

[0073] By setting the range of preset frequencies as described above, inaccurate measurement results due to excessively small values ​​are avoided, as are misjudgments due to excessively large values.

[0074] According to one embodiment of the present invention, in S50, the preset percentage ranges from 50% to 90%.

[0075] By setting the range of preset percentage values ​​as described above, inaccurate measurement results due to excessively large values ​​are avoided, as are misjudgments due to excessively small values.

[0076] According to one embodiment of the present invention, in S80, the preset threshold value ranges from 10 to 20.

[0077] By setting the range of the preset threshold as described above, inaccurate measurement results due to excessively large values ​​are avoided, as are misjudgments due to excessively small values.

[0078] According to one embodiment of the present invention, in S90, the quenching time of the superconducting magnet is obtained by the following formula:

[0079] T Qch =(T k +T j ) / 2;

[0080] In the formula, T Qch T is the quench moment of the superconducting magnet. k For the first decision moment, T j This is the second decision-making moment;

[0081] In S90, the preset time ranges from 50 to 100 µs.

[0082] like Figure 2 As shown, the present invention also provides a method for detecting quenching in low-temperature superconducting magnets based on strain signals, the method comprising:

[0083] S10, at the current time T i As the detection time;

[0084] S20. Acquire strain signal data of the superconducting magnet within a preset time period before the detection time;

[0085] S30. Perform low-pass filtering on the strain signal data of the superconducting magnet within a preset time period before the detection time to obtain the low-pass filtered signal of the superconducting magnet.

[0086] S40. Obtain the maximum value and root mean square of the low-pass filtered signal of the superconducting magnet;

[0087] S50. Determine whether the ratio of the maximum value to the root mean square of the low-pass filter signal of the superconducting magnet is greater than or equal to a preset threshold. If so, set the time T corresponding to the maximum value of the low-pass filter signal of the superconducting magnet to... j As the second decision point, proceed to S60; otherwise, proceed to the next decision point T. i+1 As the detection point, proceed to S20;

[0088] S60. Based on the strain signal data of the superconducting magnet within a preset time period before the detection time, obtain the frequency components of the superconducting magnet at each moment within the preset time period before the detection time.

[0089] S70. Calculate the energy with a frequency lower than the preset frequency in the frequency components of the superconducting magnet at each time moment, and obtain the ratio of the energy with a frequency lower than the preset frequency in the frequency components of the superconducting magnet at each time moment to the total energy of all frequencies in the frequency components of the superconducting magnet at the corresponding time moment.

[0090] S80. Determine whether there is at least one ratio greater than a preset percentage among the ratios of the energy with frequencies lower than a preset frequency in the frequency components of the superconducting magnet at each time point to the total energy of all frequencies in the frequency components of the superconducting magnet at the corresponding time point. If so, if there is only one ratio greater than the preset percentage, then the time T corresponding to the ratio greater than the preset percentage is... k As the first determination time, if there are multiple ratios greater than a preset percentage, the earliest time T among the multiple times corresponding to the multiple ratios greater than the preset percentage is selected. k This is the first decision point, and the process proceeds to S90; otherwise, the next decision point is T. i+1 As the detection point, proceed to S20;

[0091] S90. Determine whether the absolute value of the difference between the first determination time and the second determination time is less than a preset time. If so, determine that the superconducting magnet has lost quench, and obtain the quench time of the superconducting magnet based on the first determination time and the second determination time. Otherwise, proceed to the next time T. i+1 As the detection point, proceed to S20.

[0092] This invention utilizes strain signal data from a superconducting magnet within a preset time period prior to the detection time to sequentially acquire a first determination time and a second determination time via serial logic. Based on these two determination times, it determines whether the superconducting magnet has lost quench. If the superconducting magnet has lost quench, it acquires the quench time. This invention, through the measurement of physical signals, can detect quench in both multi-coil and single-coil superconducting magnets, avoiding measurement delays, increasing detection speed, reducing detection costs and sensor space requirements, and is applicable to small or compact superconducting magnets. Furthermore, the physical signal acquisition and transmission are more reliable, suitable for long-distance transmission and remote control. The use of serial logic to sequentially acquire the first and second determination times improves detection accuracy.

[0093] According to one embodiment of the present invention, in S20, acquiring strain signal data of the superconducting magnet within a preset time period prior to the detection time includes: acquiring strain signal data from T... i-△T time to T i The strain signal data of the superconducting magnet within a time period, wherein the value of ΔT ranges from 10 to 50 ms.

[0094] By setting the range of values ​​for △T as described above, we avoid inaccurate measurement results due to excessively large values, and also avoid reduced measurement speed due to excessively small values.

[0095] According to one embodiment of the present invention, in S50, the preset threshold value ranges from 10 to 20.

[0096] By setting the range of the preset threshold as described above, inaccurate measurement results due to excessively large values ​​are avoided, as are misjudgments due to excessively small values.

[0097] According to an embodiment of the present invention, in S60, obtaining the frequency components of the superconducting magnet corresponding to each moment within the preset time period before the detection time based on the strain signal data of the superconducting magnet within the preset time period before the detection time includes: performing discrete wavelet transform on the strain signal data of the superconducting magnet within the preset time period before the detection time to obtain the frequency components of the superconducting magnet corresponding to each moment within the preset time period before the detection time.

[0098] According to one embodiment of the present invention, in S70, the preset frequency ranges from 10 to 50 Hz. In S70, if one frequency in the frequency components of the superconducting magnet at each moment is less than the preset frequency, the ratio of the energy corresponding to that frequency to the total energy of all frequencies is obtained; if multiple frequencies in the frequency components of the superconducting magnet at each moment are less than the preset frequency, the ratio of the energy corresponding to each frequency less than the preset frequency to the total energy of all frequencies is obtained.

[0099] By setting the range of preset frequencies as described above, inaccurate measurement results due to excessively small values ​​are avoided, as are misjudgments due to excessively large values.

[0100] According to one embodiment of the present invention, in S80, the preset percentage ranges from 50% to 90%.

[0101] By setting the range of preset percentage values ​​as described above, inaccurate measurement results due to excessively large values ​​are avoided, as are misjudgments due to excessively small values.

[0102] According to one embodiment of the present invention, in S90, the quenching time of the superconducting magnet is obtained by the following formula:

[0103] T Qch =(T k +T j ) / 2;

[0104] In the formula, T Qch T is the quench moment of the superconducting magnet. k For the first decision moment, T j This is the second decision-making moment;

[0105] In S90, the preset time ranges from 50 to 100 µs.

[0106] The method of the present invention will be described in detail below using a high-dynamic single-coil cryogenic superconducting magnet as an example.

[0107] In this embodiment, the high-dynamic single-coil cryogenic superconducting magnet includes an inner Dewar, an outer Dewar, and a superconducting coil. The inner Dewar is disposed inside the outer Dewar, and the inner Dewar is filled with liquid helium. The superconducting coil is completely immersed in liquid helium to ensure that it always maintains a cryogenic environment and state. After the superconducting coil is energized and becomes a superconducting magnet, the magnetic field generated by the coil interacts with the current-carrying wire itself. This interaction causes the entire coil to be subjected to an outward tensile force, resulting in stretching and significant strain. The strain of the superconducting coil due to excitation changes significantly with the excitation current. By measuring the strain of the superconducting coil, the excitation state of the coil can be indirectly measured, thereby determining whether the superconducting magnet has lost its quench.

[0108] like Figure 3 As shown, when a superconducting magnet loses quench, the superconducting coil generates resistance, the current decreases, and the magnetic field decreases with the current. Consequently, the force between the magnetic field and the current is significantly reduced, ultimately leading to a decrease in the strain of the superconducting coil itself. By installing a strain sensor on the surface of the superconducting coil, the strain on the surface of the superconducting coil is detected to obtain a strain signal. Then, the strain signal is processed using the method of this invention to obtain the quench moment of the superconducting magnet.

[0109] Compared with the prior art, the present invention has the following beneficial effects:

[0110] (1) This method is not limited by the number of coils in the superconducting magnet and can be used to measure both single-coil and multi-coil superconducting magnets.

[0111] (2) This method is not limited by the slow temperature conduction after the superconducting magnet loses quench, and can be quickly detected after local quench;

[0112] (3) This method is not limited by the external space of the superconducting magnet, and the detection sensor can be built into the superconducting magnet.

[0113] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0114] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0115] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0116] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for detecting quenching in low-temperature superconducting magnets based on strain signals, characterized in that, The method includes: S10, at the current time T i As the detection time; S20. Acquire strain signal data of the superconducting magnet within a preset time period before the detection time; S30. Based on the strain signal data of the superconducting magnet within a preset time period before the detection time, obtain the frequency components of the superconducting magnet at each moment within the preset time period before the detection time. S40. Calculate the energy of the superconducting magnet at each time point whose frequency is less than the preset frequency, and obtain the ratio of the energy of the superconducting magnet at each time point whose frequency is less than the preset frequency to the total energy of all frequencies in the superconducting magnet at the corresponding time point. S50. Determine whether there is at least one ratio greater than a preset percentage among the ratios of the energy with frequencies lower than a preset frequency in the frequency components of the superconducting magnet at each time point to the total energy of all frequencies in the frequency components of the superconducting magnet at the corresponding time point. If so, if there is only one ratio greater than the preset percentage, then the time T corresponding to the ratio greater than the preset percentage is... k As the first determination time, if there are multiple ratios greater than a preset percentage, the earliest time T among the multiple times corresponding to the multiple ratios greater than the preset percentage is selected. k This is the first decision point, and the process proceeds to S60; otherwise, the next decision point is T. i+1 As the detection point, proceed to S20; S60. Perform low-pass filtering on the strain signal data of the superconducting magnet within a preset time period before the detection time to obtain the low-pass filtered signal of the superconducting magnet. S70. Obtain the maximum value and root mean square of the low-pass filtered signal of the superconducting magnet; S80. Determine whether the ratio of the maximum value to the root mean square of the low-pass filter signal of the superconducting magnet is greater than or equal to a preset threshold. If so, set the time T corresponding to the maximum value of the low-pass filter signal of the superconducting magnet to... j As the second decision point, proceed to S90; otherwise, proceed to the next decision point T. i+1 As the detection point, proceed to S20; S90. Determine whether the absolute value of the difference between the first determination time and the second determination time is less than a preset time. If so, determine that the superconducting magnet has lost quench, and obtain the quench time of the superconducting magnet based on the first determination time and the second determination time. Otherwise, proceed to the next time T. i+1 As the detection point, proceed to S20.

2. The method according to claim 1, characterized in that, In S20, acquiring the strain signal data of the superconducting magnet within a preset time period prior to the detection time includes: acquiring the strain signal data from T... i -△T time to T i The strain signal data of the superconducting magnet within a time period, wherein the value of ΔT ranges from 10 to 50 ms.

3. The method according to claim 1 or 2, characterized in that, In S30, obtaining the frequency components of the superconducting magnet at each moment within the preset time period before the detection time based on the strain signal data of the superconducting magnet within the preset time period before the detection time includes: performing discrete wavelet transform on the strain signal data of the superconducting magnet within the preset time period before the detection time to obtain the frequency components of the superconducting magnet at each moment within the preset time period before the detection time.

4. The method according to claim 1 or 2, characterized in that, In S90, the quenching time of the superconducting magnet is obtained by the following formula: T Qch =(T k +T j ) / 2; In the formula, T Qch T is the quench moment of the superconducting magnet. k For the first decision moment, T j This is the second decision-making moment; In S90, the preset time ranges from 50 to 100 µs.

5. The method according to claim 1, characterized in that, In S40, the preset frequency ranges from 10 to 50 Hz; in S50, the preset percentage ranges from 50 to 90%; and in S80, the preset threshold ranges from 10 to 20.

6. A method for detecting quenching in low-temperature superconducting magnets based on strain signals, characterized in that, The method includes: S10, at the current time T i As the detection time; S20. Acquire strain signal data of the superconducting magnet within a preset time period before the detection time; S30. Perform low-pass filtering on the strain signal data of the superconducting magnet within a preset time period before the detection time to obtain the low-pass filtered signal of the superconducting magnet. S40. Obtain the maximum value and root mean square of the low-pass filtered signal of the superconducting magnet; S50. Determine whether the ratio of the maximum value to the root mean square of the low-pass filter signal of the superconducting magnet is greater than or equal to a preset threshold. If so, set the time T corresponding to the maximum value of the low-pass filter signal of the superconducting magnet to... j As the second decision point, proceed to S60; otherwise, proceed to the next decision point T. i+1 As the detection point, proceed to S20; S60. Based on the strain signal data of the superconducting magnet within a preset time period before the detection time, obtain the frequency components of the superconducting magnet at each moment within the preset time period before the detection time. S70. Calculate the energy with a frequency lower than the preset frequency in the frequency components of the superconducting magnet at each time moment, and obtain the ratio of the energy with a frequency lower than the preset frequency in the frequency components of the superconducting magnet at each time moment to the total energy of all frequencies in the frequency components of the superconducting magnet at the corresponding time moment. S80. Determine whether there is at least one ratio greater than a preset percentage among the ratios of the energy with frequencies lower than a preset frequency in the frequency components of the superconducting magnet at each time point to the total energy of all frequencies in the frequency components of the superconducting magnet at the corresponding time point. If so, if there is only one ratio greater than the preset percentage, then the time T corresponding to the ratio greater than the preset percentage is... k As the first determination time, if there are multiple ratios greater than a preset percentage, the earliest time T among the multiple times corresponding to the multiple ratios greater than the preset percentage is selected. k This is the first decision point, and the process proceeds to S90; otherwise, the next decision point is T. i+1 As the detection point, proceed to S20; S90. Determine whether the absolute value of the difference between the first determination time and the second determination time is less than a preset time. If so, determine that the superconducting magnet has lost quench, and obtain the quench time of the superconducting magnet based on the first determination time and the second determination time. Otherwise, proceed to the next time T. i+1 As the detection point, proceed to S20.

7. The method according to claim 6, characterized in that, In S20, acquiring the strain signal data of the superconducting magnet within a preset time period prior to the detection time includes: acquiring the strain signal data from T... i -△T time to T i The strain signal data of the superconducting magnet within a time period, wherein the value of ΔT ranges from 10 to 50 ms.

8. The method according to claim 6 or 7, characterized in that, In S60, obtaining the frequency components of the superconducting magnet at each moment within the preset time period before the detection time based on the strain signal data of the superconducting magnet within the preset time period before the detection time includes: performing discrete wavelet transform on the strain signal data of the superconducting magnet within the preset time period before the detection time to obtain the frequency components of the superconducting magnet at each moment within the preset time period before the detection time.

9. The method according to claim 6 or 7, characterized in that, In S90, the quenching time of the superconducting magnet is obtained by the following formula: T Qch =(T k +T j ) / 2; In the formula, T Qch T is the quench moment of the superconducting magnet. k For the first decision moment, T j This is the second decision-making moment; In S90, the preset time ranges from 50 to 100 µs.

10. The method according to claim 6 or 7, characterized in that, In S50, the preset threshold value ranges from 10 to 20; in S70, the preset frequency value ranges from 10 to 50 Hz; and in S80, the preset percentage value ranges from 50 to 90%.

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